Refactor BalancedMetricResolver to allow HDFS and FILE backing, add callbacks for major events, begin working on tests

Refactor BalancedMetricResolver, allow FILE or HDFS persister, add callbacks for events, begin working on testing

Fixes

analytics/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>timely-analytics</artifactId>
   <!--
@@ -68,6 +68,7 @@
     <pluginManagement>
       <plugins>
         <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-compiler-plugin</artifactId>
           <configuration>
             <compilerId>jdt</compilerId>
@@ -76,7 +77,7 @@
             <dependency>
               <groupId>org.eclipse.tycho</groupId>
               <artifactId>tycho-compiler-jdt</artifactId>
-              <version>0.21.0</version>
+              <version>1.4.0</version>
             </dependency>
           </dependencies>
         </plugin>

analytics/src/main/java/timely/analytics/flink/SummarizationJob.java

@@ -67,7 +67,7 @@ public class SummarizationJob {
         })
         .name("Metric Windows")
         .addSink(
-    		new SocketClientSink<MetricHistogram>(jp.getTimelyHostname(), jp.getTimelyTcpPort(),
+            new SocketClientSink<MetricHistogram>(jp.getTimelyHostname(), jp.getTimelyTcpPort(),
                     new MetricHistogram(), 2, true) {
 
                 private final Logger LOG = LoggerFactory

balancer/bin/timely-balancer.sh

@@ -32,7 +32,7 @@ $JAVA_HOME/bin/jar xf ${LIB_DIR}/netty-all*.jar META-INF/native/libnetty_transpo
 popd
 
 export CLASSPATH="${CONF_DIR}:${LIB_DIR}/*:${HADOOP_CONF_DIR}"
-JVM_ARGS="-Xmx1G -Xms1G -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS}" -Dlog4j.configurationFile=${CONF_DIR}/log4j2-spring.xml
+JVM_ARGS="-Xmx1G -Xms1G -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS} -Dlog4j.configurationFile=${CONF_DIR}/log4j2-spring.xml"
 JVM_ARGS="${JVM_ARGS} -DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector"
 JVM_ARGS="${JVM_ARGS} -Djava.library.path=${NATIVE_DIR}"
 

balancer/conf/timely-balancer.yml

@@ -111,6 +111,7 @@ timely-balancer:
     flush-interval-seconds: 30
     scanner-read-ahead: 1
     subscription-batch-size: 5000
+    incomingBufferSize: 50000000
     wsClientPool:
       minIdlePerKey: 0
       maxIdlePerKey: 40

balancer/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>timely-balancer</artifactId>
   <dependencies>
@@ -108,6 +108,10 @@
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-minicluster</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.glassfish.tyrus</groupId>
+      <artifactId>tyrus-client</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
@@ -162,7 +166,6 @@
     <dependency>
       <groupId>io.netty</groupId>
       <artifactId>netty-tcnative-boringssl-static</artifactId>
-      <version>${version.netty-tcnative}</version>
       <scope>runtime</scope>
     </dependency>
     <dependency>

balancer/src/main/java/timely/balancer/ArrivalRate.java

@@ -1,7 +1,7 @@
 package timely.balancer;
 
-import java.util.Timer;
-import java.util.TimerTask;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
 
 import com.google.common.util.concurrent.AtomicDouble;
@@ -20,38 +20,26 @@ public class ArrivalRate {
     private AtomicDouble longTermRate = new AtomicDouble(0);
     private AtomicLong longTermLastReset = new AtomicLong(0);
 
-    public ArrivalRate(Timer timer) {
+    public ArrivalRate(ScheduledExecutorService arrivalRateExecutor) {
         long now = System.currentTimeMillis();
         shortTermLastReset.set(now);
         mediumTermLastReset.set(now);
         longTermLastReset.set(now);
 
         // 2 minute
-        timer.schedule(new TimerTask() {
-
-            @Override
-            public void run() {
-                resetShort();
-            }
-        }, 120000, 120000);
+        arrivalRateExecutor.scheduleAtFixedRate(() -> {
+            resetShort();
+        }, 2, 2, TimeUnit.MINUTES);
 
         // 5 minute
-        timer.schedule(new TimerTask() {
-
-            @Override
-            public void run() {
-                resetMedium();
-            }
-        }, 300000, 300000);
+        arrivalRateExecutor.scheduleAtFixedRate(() -> {
+            resetMedium();
+        }, 5, 5, TimeUnit.MINUTES);
 
         // 15 minute
-        timer.schedule(new TimerTask() {
-
-            @Override
-            public void run() {
-                resetLong();
-            }
-        }, 900000, 900000);
+        arrivalRateExecutor.scheduleAtFixedRate(() -> {
+            resetLong();
+        }, 15, 15, TimeUnit.MINUTES);
     }
 
     private void resetShort() {

balancer/src/main/java/timely/balancer/Balancer.java

@@ -25,6 +25,7 @@ import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.WriteBufferWaterMark;
 import io.netty.channel.epoll.EpollChannelOption;
 import io.netty.channel.epoll.EpollDatagramChannel;
 import io.netty.channel.epoll.EpollEventLoopGroup;
@@ -56,6 +57,7 @@ import io.netty.handler.stream.ChunkedWriteHandler;
 import io.netty.handler.timeout.IdleStateHandler;
 import io.netty.util.NettyRuntime;
 import io.netty.util.internal.SystemPropertyUtil;
+import org.apache.accumulo.core.conf.AccumuloConfiguration;
 import org.apache.curator.RetryPolicy;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.CuratorFrameworkFactory;
@@ -75,7 +77,7 @@ import timely.balancer.connection.http.HttpClientPool;
 import timely.balancer.connection.tcp.TcpClientPool;
 import timely.balancer.connection.udp.UdpClientPool;
 import timely.balancer.connection.ws.WsClientPool;
-import timely.balancer.healthcheck.HealthChecker;
+import timely.balancer.healthcheck.TcpHealthChecker;
 import timely.balancer.netty.http.HttpRelayHandler;
 import timely.balancer.netty.tcp.TcpRelayHandler;
 import timely.balancer.netty.udp.UdpRelayHandler;
@@ -143,8 +145,11 @@ public class Balancer {
         this.balancerConfig = balancerConf;
     }
 
-    protected static ConfigurableApplicationContext initializeConfiguration(String[] args) {
-        return new SpringApplicationBuilder(SpringBootstrap.class).web(WebApplicationType.NONE).run(args);
+    protected static ConfigurableApplicationContext initializeContext(String[] args) {
+        SpringApplicationBuilder builder = new SpringApplicationBuilder(SpringBootstrap.class);
+        builder.web(WebApplicationType.NONE);
+        builder.registerShutdownHook(false);
+        return builder.run(args);
     }
 
     private void shutdownHook() {
@@ -176,8 +181,9 @@ public class Balancer {
             channelFutures.add(wsChannelHandle.close());
         }
 
+        int udpChannel = 1;
         for (Channel c : udpChannelHandleList) {
-            LOG.info("Closing udpChannelHandle");
+            LOG.info("Closing udpChannelHandle #" + udpChannel++);
             channelFutures.add(c.close());
         }
 
@@ -186,14 +192,13 @@ public class Balancer {
             try {
                 f.get();
             } catch (final Exception e) {
-                LOG.error("Error while shutting down channel: {}", f.channel().config());
-                LOG.error("{}", e.getMessage());
-                e.printStackTrace();
+                LOG.error("Channel:" + f.channel().config() + " -> " + e.getMessage(), e);
             }
         });
 
-        Integer quietPeriod = balancerConfig.getServer().getShutdownQuietPeriod();
+        int quietPeriod = balancerConfig.getServer().getShutdownQuietPeriod();
         List<Future<?>> groupFutures = new ArrayList<>();
+
         if (tcpBossGroup != null) {
             LOG.info("Shutting down tcpBossGroup");
             groupFutures.add(tcpBossGroup.shutdownGracefully(quietPeriod, 10, TimeUnit.SECONDS));
@@ -238,9 +243,7 @@ public class Balancer {
             try {
                 f.get();
             } catch (final Exception e) {
-                LOG.error("Error while shutting down group: {}", f.toString());
-                LOG.error("{}", e.getMessage());
-                e.printStackTrace();
+                LOG.error("Group:" + f.toString() + " -> " + e.getMessage(), e);
             }
         });
 
@@ -251,14 +254,29 @@ public class Balancer {
             LOG.error("Error closing WebSocketRequestDecoder during shutdown", e);
         }
 
+        if (this.metricResolver != null) {
+            try {
+                LOG.info("Closing metricResolver");
+                this.metricResolver.stop();
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
+        }
+
+        if (curatorFramework != null) {
+            try {
+                LOG.info("Closing curatorFramework");
+                curatorFramework.close();
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
+        }
+
         if (applicationContext != null) {
             LOG.info("Closing applicationContext");
             applicationContext.close();
         }
 
-        if (curatorFramework != null) {
-            curatorFramework.close();
-        }
         this.shutdown = true;
         LOG.info("Server shut down.");
     }
@@ -359,7 +377,9 @@ public class Balancer {
 
         // start curator framework
         RetryPolicy retryPolicy = new RetryForever(1000);
-        curatorFramework = CuratorFrameworkFactory.newClient(balancerConfig.getZooKeeper().getServers(), 30000, 1000,
+        int timeout = Long.valueOf(AccumuloConfiguration.getTimeInMillis(balancerConfig.getZooKeeper().getTimeout()))
+                .intValue();
+        curatorFramework = CuratorFrameworkFactory.newClient(balancerConfig.getZooKeeper().getServers(), timeout, 10000,
                 retryPolicy);
         curatorFramework.start();
         ensureZkPaths(curatorFramework, zkPaths);
@@ -397,8 +417,9 @@ public class Balancer {
         for (int x = 0; x < balancerConfig.getServer().getNumTcpPools(); x++) {
             tcpClientPools.add(new TcpClientPool(this.balancerConfig));
         }
-        HealthChecker healthChecker = new HealthChecker(this.balancerConfig, tcpClientPools.get(0));
+        TcpHealthChecker healthChecker = new TcpHealthChecker(this.balancerConfig, tcpClientPools.get(0));
         this.metricResolver = new BalancedMetricResolver(curatorFramework, this.balancerConfig, healthChecker);
+        this.metricResolver.start();
 
         final ServerBootstrap tcpServer = new ServerBootstrap();
         tcpServer.group(tcpBossGroup, tcpWorkerGroup);
@@ -450,10 +471,9 @@ public class Balancer {
         wsServer.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
         wsServer.option(ChannelOption.SO_BACKLOG, 128);
         wsServer.option(ChannelOption.SO_KEEPALIVE, true);
-        /* Not sure if next three lines are necessary */
+        /* Not sure if next two lines are necessary */
         wsServer.option(ChannelOption.SO_SNDBUF, 1048576);
-        wsServer.option(ChannelOption.WRITE_BUFFER_HIGH_WATER_MARK, 838860);
-        wsServer.option(ChannelOption.WRITE_BUFFER_LOW_WATER_MARK, 620145);
+        wsServer.option(ChannelOption.WRITE_BUFFER_WATER_MARK, new WriteBufferWaterMark(620145, 838860));
         wsChannelHandle = wsServer.bind(wsIp, wsPort).sync().channel();
         final String wsAddress = ((InetSocketAddress) wsChannelHandle.localAddress()).getAddress().getHostAddress();
 
@@ -478,12 +498,12 @@ public class Balancer {
 
     public static void main(String[] args) throws Exception {
 
-        Balancer.applicationContext = Balancer.initializeConfiguration(args);
-        BalancerConfiguration balancerConf = applicationContext.getBean(BalancerConfiguration.class);
+        Balancer.applicationContext = Balancer.initializeContext(args);
+        BalancerConfiguration balancerConf = Balancer.applicationContext.getBean(BalancerConfiguration.class);
 
-        Balancer b = new Balancer(balancerConf);
+        Balancer balancer = new Balancer(balancerConf);
         try {
-            b.run();
+            balancer.run();
             LATCH.await();
         } catch (final InterruptedException e) {
             LOG.info("Server shutting down.");
@@ -491,7 +511,7 @@ public class Balancer {
             LOG.error("Error running server.", e);
         } finally {
             try {
-                b.shutdown();
+                balancer.shutdown();
             } catch (Exception e) {
                 System.exit(1);
             }
@@ -515,11 +535,13 @@ public class Balancer {
                 ch.pipeline().addLast("chunker", new ChunkedWriteHandler());
                 ch.pipeline().addLast("queryDecoder", new timely.netty.http.HttpRequestDecoder(
                         balancerConfig.getSecurity(), balancerConfig.getHttp()));
-                ch.pipeline().addLast("fileServer", new HttpStaticFileServerHandler());
+                ch.pipeline().addLast("fileServer", new HttpStaticFileServerHandler().setIgnoreSslHandshakeErrors(
+                        balancerConfig.getSecurity().getServerSsl().isUseGeneratedKeypair()));
                 ch.pipeline().addLast("login",
                         new X509LoginRequestHandler(balancerConfig.getSecurity(), balancerConfig.getHttp()));
                 ch.pipeline().addLast("httpRelay", new HttpRelayHandler(metricResolver, httpClientPool));
-                ch.pipeline().addLast("error", new TimelyExceptionHandler());
+                ch.pipeline().addLast("error", new TimelyExceptionHandler().setIgnoreSslHandshakeErrors(
+                        balancerConfig.getSecurity().getServerSsl().isUseGeneratedKeypair()));
             }
         };
     }
@@ -567,7 +589,7 @@ public class Balancer {
                 ch.pipeline().addLast("idle-handler",
                         new IdleStateHandler(balancerConfig.getWebsocket().getTimeout(), 0, 0));
                 ch.pipeline().addLast("ws-protocol",
-                        new WebSocketServerProtocolHandler(WS_PATH, null, true, 65536, true));
+                        new WebSocketServerProtocolHandler(WS_PATH, null, true, 65536, false, true));
                 ch.pipeline().addLast("wsDecoder", new WebSocketRequestDecoder(balancerConfig.getSecurity()));
                 ch.pipeline().addLast("httpRelay", new WsRelayHandler(balancerConfig, metricResolver, wsClientPool));
                 ch.pipeline().addLast("error", new WSTimelyExceptionHandler());

balancer/src/main/java/timely/balancer/configuration/BalancerConfiguration.java

@@ -49,6 +49,16 @@ public class BalancerConfiguration {
 
     private int serverSuccessesBeforeUp = 3;
 
+    private String metricAssignmentPersisterType = "HDFS";
+
+    private long balanceDelay = 900000;
+
+    private long balancePeriod = 900000;
+
+    private long persistDelay = 10000;
+
+    private long persistPeriod = 60000;
+
     public ZooKeeper getZooKeeper() {
         return zooKeeper;
     }
@@ -120,4 +130,44 @@ public class BalancerConfiguration {
     public void setServerSuccessesBeforeUp(int serverSuccessesBeforeUp) {
         this.serverSuccessesBeforeUp = serverSuccessesBeforeUp;
     }
+
+    public String getMetricAssignmentPersisterType() {
+        return metricAssignmentPersisterType;
+    }
+
+    public void setMetricAssignmentPersisterType(String metricAssignmentPersisterType) {
+        this.metricAssignmentPersisterType = metricAssignmentPersisterType;
+    }
+
+    public void setBalanceDelay(long balanceDelay) {
+        this.balanceDelay = balanceDelay;
+    }
+
+    public long getBalanceDelay() {
+        return balanceDelay;
+    }
+
+    public void setBalancePeriod(long balancePeriod) {
+        this.balancePeriod = balancePeriod;
+    }
+
+    public long getBalancePeriod() {
+        return balancePeriod;
+    }
+
+    public void setPersistDelay(long persistDelay) {
+        this.persistDelay = persistDelay;
+    }
+
+    public long getPersistDelay() {
+        return persistDelay;
+    }
+
+    public void setPersistPeriod(long persistPeriod) {
+        this.persistPeriod = persistPeriod;
+    }
+
+    public long getPersistPeriod() {
+        return persistPeriod;
+    }
 }

balancer/src/main/java/timely/balancer/configuration/BalancerHttp.java

@@ -3,6 +3,7 @@ package timely.balancer.configuration;
 import javax.validation.Valid;
 
 import org.apache.commons.pool2.impl.GenericKeyedObjectPoolConfig;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 import timely.configuration.Http;
 
@@ -10,9 +11,9 @@ public class BalancerHttp extends Http {
 
     @Valid
     @NestedConfigurationProperty
-    private GenericKeyedObjectPoolConfig httpClientPool = new GenericKeyedObjectPoolConfig();
+    private GenericKeyedObjectPoolConfig<CloseableHttpClient> httpClientPool = new GenericKeyedObjectPoolConfig<>();
 
-    public GenericKeyedObjectPoolConfig getHttpClientPool() {
+    public GenericKeyedObjectPoolConfig<CloseableHttpClient> getHttpClientPool() {
         return httpClientPool;
     }
 }

balancer/src/main/java/timely/balancer/configuration/BalancerServer.java

@@ -4,27 +4,29 @@ import javax.validation.Valid;
 
 import org.apache.commons.pool2.impl.GenericKeyedObjectPoolConfig;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
+import timely.client.tcp.TcpClient;
+import timely.client.udp.UdpClient;
 import timely.configuration.Server;
 
 public class BalancerServer extends Server {
 
     @Valid
     @NestedConfigurationProperty
-    private GenericKeyedObjectPoolConfig udpClientPool = new GenericKeyedObjectPoolConfig();
+    private GenericKeyedObjectPoolConfig<UdpClient> udpClientPool = new GenericKeyedObjectPoolConfig<>();
 
     @Valid
     @NestedConfigurationProperty
-    private GenericKeyedObjectPoolConfig tcpClientPool = new GenericKeyedObjectPoolConfig();
+    private GenericKeyedObjectPoolConfig<TcpClient> tcpClientPool = new GenericKeyedObjectPoolConfig<>();
 
     private int numTcpPools = 1;
 
     private int tcpBufferSize = -1;
 
-    public GenericKeyedObjectPoolConfig getUdpClientPool() {
+    public GenericKeyedObjectPoolConfig<UdpClient> getUdpClientPool() {
         return udpClientPool;
     }
 
-    public GenericKeyedObjectPoolConfig getTcpClientPool() {
+    public GenericKeyedObjectPoolConfig<TcpClient> getTcpClientPool() {
         return tcpClientPool;
     }
 

balancer/src/main/java/timely/balancer/configuration/BalancerWebsocket.java

@@ -4,15 +4,26 @@ import javax.validation.Valid;
 
 import org.apache.commons.pool2.impl.GenericKeyedObjectPoolConfig;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
+import timely.client.websocket.subscription.WebSocketSubscriptionClient;
 import timely.configuration.Websocket;
 
 public class BalancerWebsocket extends Websocket {
 
     @Valid
     @NestedConfigurationProperty
-    private GenericKeyedObjectPoolConfig wsClientPool = new GenericKeyedObjectPoolConfig();
+    private GenericKeyedObjectPoolConfig<WebSocketSubscriptionClient> wsClientPool = new GenericKeyedObjectPoolConfig<>();
 
-    public GenericKeyedObjectPoolConfig getWsClientPool() {
+    public GenericKeyedObjectPoolConfig<WebSocketSubscriptionClient> getWsClientPool() {
         return wsClientPool;
     }
+
+    public int incomingBufferSize = 50000000;
+
+    public int getIncomingBufferSize() {
+        return incomingBufferSize;
+    }
+
+    public void setIncomingBufferSize(int incomingBufferSize) {
+        this.incomingBufferSize = incomingBufferSize;
+    }
 }

balancer/src/main/java/timely/balancer/configuration/ZooKeeper.java

@@ -1,9 +1,14 @@
 package timely.balancer.configuration;
 
+import javax.validation.constraints.NotBlank;
+
 public class ZooKeeper {
 
     private String servers;
 
+    @NotBlank
+    private String timeout = "120s";
+
     public String getServers() {
         return servers;
     }
@@ -11,4 +16,12 @@ public class ZooKeeper {
     public void setServers(String servers) {
         this.servers = servers;
     }
+
+    public String getTimeout() {
+        return timeout;
+    }
+
+    public void setTimeout(String timeout) {
+        this.timeout = timeout;
+    }
 }

balancer/src/main/java/timely/balancer/connection/TimelyBalancedHost.java

@@ -1,7 +1,5 @@
 package timely.balancer.connection;
 
-import java.util.Timer;
-
 import org.apache.commons.lang3.builder.EqualsBuilder;
 import org.apache.commons.lang3.builder.HashCodeBuilder;
 import org.apache.commons.lang3.builder.ToStringBuilder;
@@ -13,7 +11,6 @@ import timely.balancer.configuration.BalancerConfiguration;
 public class TimelyBalancedHost {
 
     private static final Logger LOG = LoggerFactory.getLogger(TimelyBalancedHost.class);
-    static private Timer arrivalRateTimer = new Timer("ArrivalRateTimerTBH", true);
 
     private String host;
     private int tcpPort;
@@ -24,34 +21,29 @@ public class TimelyBalancedHost {
     private BalancerConfiguration balancerConfig;
     private int failures = 0;
     private int successes = 0;
-    private ArrivalRate arrivalRate = new ArrivalRate(arrivalRateTimer);
+    private ArrivalRate arrivalRate = null;
 
-    public TimelyBalancedHost() {
+    private TimelyBalancedHost() {
 
     }
 
-    public TimelyBalancedHost(String host, int tcpPort, int httpPort, int wsPort, int udpPort) {
+    private TimelyBalancedHost(String host, int tcpPort, int httpPort, int wsPort, int udpPort,
+            ArrivalRate arrivalRate) {
         this.host = host;
         this.tcpPort = tcpPort;
         this.httpPort = httpPort;
         this.wsPort = wsPort;
         this.udpPort = udpPort;
+        this.arrivalRate = arrivalRate;
     }
 
-    public TimelyBalancedHost(String host, int basePort) {
-        this.host = host;
-        this.tcpPort = basePort;
-        this.httpPort = basePort + 1;
-        this.wsPort = basePort + 2;
-        this.udpPort = basePort + 3;
-    }
-
-    static public TimelyBalancedHost of(String host, int tcpPort, int httpPort, int wsPort, int udpPort) {
-        return new TimelyBalancedHost(host, tcpPort, httpPort, wsPort, udpPort);
+    static public TimelyBalancedHost of(String host, int tcpPort, int httpPort, int wsPort, int udpPort,
+            ArrivalRate arrivalRate) {
+        return new TimelyBalancedHost(host, tcpPort, httpPort, wsPort, udpPort, arrivalRate);
     }
 
     static public TimelyBalancedHost of(String host, int basePort) {
-        return new TimelyBalancedHost(host, basePort);
+        return new TimelyBalancedHost(host, basePort, basePort + 1, basePort + 2, basePort + 3, null);
     }
 
     public void setBalancerConfig(BalancerConfiguration balancerConfig) {
@@ -141,11 +133,17 @@ public class TimelyBalancedHost {
     }
 
     public void arrived() {
-        arrivalRate.arrived();
+        if (this.arrivalRate != null) {
+            this.arrivalRate.arrived();
+        }
     }
 
     public double getArrivalRate() {
-        return arrivalRate.getRate();
+        if (this.arrivalRate == null) {
+            return 0;
+        } else {
+            return this.arrivalRate.getRate();
+        }
     }
 
     @Override
@@ -186,4 +184,11 @@ public class TimelyBalancedHost {
         builder.append(isUp);
         return builder.toString();
     }
+
+    public static String toStringShort(TimelyBalancedHost tbh) {
+        if (tbh == null) {
+            return null;
+        }
+        return tbh.host + ":" + tbh.tcpPort;
+    }
 }

balancer/src/main/java/timely/balancer/connection/http/HttpClientPool.java

@@ -4,16 +4,12 @@ import javax.net.ssl.SSLContext;
 
 import org.apache.commons.pool2.impl.GenericKeyedObjectPool;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import timely.balancer.configuration.BalancerHttp;
 import timely.balancer.configuration.BalancerSecurity;
 import timely.balancer.connection.TimelyBalancedHost;
 
 public class HttpClientPool extends GenericKeyedObjectPool<TimelyBalancedHost, CloseableHttpClient> {
 
-    private static final Logger LOG = LoggerFactory.getLogger(HttpClientPool.class);
-
     public HttpClientPool(BalancerSecurity balancerSecurity, BalancerHttp http, SSLContext sslContext) {
         super(new HttpClientFactory(balancerSecurity, sslContext), http.getHttpClientPool());
     }

balancer/src/main/java/timely/balancer/connection/ws/WsClientFactory.java

@@ -22,7 +22,7 @@ public class WsClientFactory implements KeyedPooledObjectFactory<TimelyBalancedH
     @Override
     public PooledObject<WebSocketSubscriptionClient> makeObject(TimelyBalancedHost k) throws Exception {
 
-        int bufferSize = balancerConfig.getWebsocket().getSubscriptionBatchSize() * 500;
+        int bufferSize = balancerConfig.getWebsocket().getIncomingBufferSize();
         WebSocketSubscriptionClient client = new WebSocketSubscriptionClient(sslContext, k.getHost(), k.getHttpPort(),
                 k.getWsPort(), balancerConfig.getSecurity().getClientSsl().isUseClientCert(),
                 balancerConfig.isLoginRequired(), "", "",

balancer/src/main/java/timely/balancer/healthcheck/HealthChecker.java

@@ -1,53 +1,12 @@
 package timely.balancer.healthcheck;
 
-import java.util.ArrayList;
 import java.util.List;
-import java.util.Timer;
-import java.util.TimerTask;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-import timely.balancer.configuration.BalancerConfiguration;
 import timely.balancer.connection.TimelyBalancedHost;
-import timely.balancer.connection.tcp.TcpClientPool;
 
-public class HealthChecker {
+public interface HealthChecker {
 
-    private static final Logger LOG = LoggerFactory.getLogger(HealthChecker.class);
-    private List<TimelyBalancedHost> timelyHosts = new ArrayList<>();
-    private Timer timer;
-    final private TCPServerHealthCheck tcpServerHealthCheck;
-    private TimerTask check = new TimerTask() {
+    public void setTimelyHosts(List<TimelyBalancedHost> timelyHosts);
 
-        @Override
-        public void run() {
-            synchronized (timelyHosts) {
-                for (TimelyBalancedHost h : timelyHosts) {
-                    try {
-                        if (tcpServerHealthCheck.isServerHealthy(h)) {
-                            h.reportSuccess();
-                        } else {
-                            h.reportFailure();
-                        }
-                    } catch (Exception e) {
-                        LOG.error(e.getMessage(), e);
-                        h.reportFailure();
-                    }
-                }
-            }
-        }
-    };
-
-    public HealthChecker(BalancerConfiguration config, TcpClientPool tcpClientPool) {
-        this.tcpServerHealthCheck = new TCPServerHealthCheck(tcpClientPool);
-        this.timer = new Timer("HealthCheckerThread", true);
-        this.timer.scheduleAtFixedRate(check, 0, config.getCheckServerHealthInterval());
-    }
-
-    public void setTimelyHosts(List<TimelyBalancedHost> timelyHosts) {
-        synchronized (timelyHosts) {
-            this.timelyHosts.clear();
-            this.timelyHosts.addAll(timelyHosts);
-        }
-    }
+    public void close() throws Exception;
 }

balancer/src/main/java/timely/balancer/healthcheck/TcpHealthChecker.java

@@ -0,0 +1,62 @@
+package timely.balancer.healthcheck;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import timely.balancer.configuration.BalancerConfiguration;
+import timely.balancer.connection.TimelyBalancedHost;
+import timely.balancer.connection.tcp.TcpClientPool;
+
+public class TcpHealthChecker implements HealthChecker {
+
+    private static final Logger LOG = LoggerFactory.getLogger(TcpHealthChecker.class);
+    private List<TimelyBalancedHost> timelyHosts = new ArrayList<>();
+    private ScheduledExecutorService executorService = Executors.newScheduledThreadPool(1);
+    final private TCPServerHealthCheck tcpServerHealthCheck;
+
+    public TcpHealthChecker(BalancerConfiguration config, TcpClientPool tcpClientPool) {
+        this.tcpServerHealthCheck = new TCPServerHealthCheck(tcpClientPool);
+        this.executorService.scheduleAtFixedRate(() -> {
+            synchronized (timelyHosts) {
+                for (TimelyBalancedHost h : timelyHosts) {
+                    try {
+                        if (tcpServerHealthCheck.isServerHealthy(h)) {
+                            h.reportSuccess();
+                        } else {
+                            h.reportFailure();
+                        }
+                    } catch (Exception e) {
+                        LOG.error(e.getMessage(), e);
+                        h.reportFailure();
+                    }
+                }
+            }
+        }, 0, config.getCheckServerHealthInterval(), TimeUnit.MILLISECONDS);
+    }
+
+    @Override
+    public void setTimelyHosts(List<TimelyBalancedHost> timelyHosts) {
+        synchronized (timelyHosts) {
+            this.timelyHosts.clear();
+            this.timelyHosts.addAll(timelyHosts);
+        }
+    }
+
+    public void close() throws Exception {
+        this.executorService.shutdown();
+        try {
+            this.executorService.awaitTermination(5, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+
+        } finally {
+            if (!this.executorService.isTerminated()) {
+                this.executorService.shutdownNow();
+            }
+        }
+    }
+}

balancer/src/main/java/timely/balancer/netty/http/HttpRelayHandler.java

@@ -1,6 +1,6 @@
 package timely.balancer.netty.http;
 
-import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_LENGTH;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
 
 import java.io.ByteArrayOutputStream;
 import java.net.URLEncoder;
@@ -67,7 +67,7 @@ public class HttpRelayHandler extends SimpleChannelInboundHandler<HttpRequest> i
         try {
             try {
                 request = msg.getHttpRequest();
-                String originalURI = request.getUri();
+                String originalURI = request.uri();
                 originalURI = encodeURI(originalURI);
 
                 String metric = null;
@@ -101,7 +101,7 @@ public class HttpRelayHandler extends SimpleChannelInboundHandler<HttpRequest> i
 
                 List<Header> relayedHeaderList = new ArrayList<>();
                 for (Map.Entry<String, String> h : headers.entries()) {
-                    if (!h.getKey().equals(CONTENT_LENGTH)) {
+                    if (!h.getKey().equals(CONTENT_LENGTH.toString())) {
                         relayedHeaderList.add(new BasicHeader(h.getKey(), h.getValue()));
                     }
                 }
@@ -109,14 +109,14 @@ public class HttpRelayHandler extends SimpleChannelInboundHandler<HttpRequest> i
                 relayedHeaderList.toArray(headerArray);
 
                 String relayURI = "https://" + k.getHost() + ":" + k.getHttpPort() + originalURI;
-                if (request.getMethod().equals(HttpMethod.GET)) {
+                if (request.method().equals(HttpMethod.GET)) {
                     HttpUriRequest relayedRequest = new HttpGet(relayURI);
                     if (headerArray.length > 0) {
                         relayedRequest.setHeaders(headerArray);
                     }
                     relayedResponse = client.execute(relayedRequest);
 
-                } else if (request.getMethod().equals(HttpMethod.POST)) {
+                } else if (request.method().equals(HttpMethod.POST)) {
                     HttpPost relayedRequest = new HttpPost(relayURI);
 
                     String content = request.content().toString(StandardCharsets.UTF_8);
@@ -170,7 +170,7 @@ public class HttpRelayHandler extends SimpleChannelInboundHandler<HttpRequest> i
             if (client != null && k != null) {
                 httpClientPool.returnObject(k, client);
             } else {
-                LOG.error("NOT RETURNING CONNECTION! " + msg.getHttpRequest().getUri());
+                LOG.error("NOT RETURNING CONNECTION! " + msg.getHttpRequest().uri());
             }
         }
     }

balancer/src/main/java/timely/balancer/netty/ws/WsClientHandler.java

@@ -45,7 +45,7 @@ public class WsClientHandler extends ClientHandler {
             Multimap<String, String> proxyRequestHeaders = HashMultimap.create();
             ProxiedEntityUtils.addProxyHeaders(proxyRequestHeaders, token.getClientCert());
             for (String s : proxyRequestHeaders.keySet()) {
-                headers.put(s, new ArrayList(proxyRequestHeaders.get(s)));
+                headers.put(s, new ArrayList<>(proxyRequestHeaders.get(s)));
             }
         }
 
@@ -53,7 +53,7 @@ public class WsClientHandler extends ClientHandler {
         for (String s : originalRequestHeaders.keySet()) {
             if (!headers.containsKey(s)) {
                 // add pre-existing values if key does not exist in proxyRequest
-                headers.put(s, new ArrayList(originalRequestHeaders.get(s)));
+                headers.put(s, new ArrayList<>(originalRequestHeaders.get(s)));
             }
         }
     }

balancer/src/main/java/timely/balancer/resolver/BalancedMetricResolver.java

@@ -4,10 +4,14 @@ import static timely.Server.SERVICE_DISCOVERY_PATH;
 import static timely.balancer.Balancer.ASSIGNMENTS_LAST_UPDATED_PATH;
 import static timely.balancer.Balancer.ASSIGNMENTS_LOCK_PATH;
 import static timely.balancer.Balancer.LEADER_LATCH_PATH;
+import static timely.balancer.resolver.eventing.MetricAssignedEvent.Reason.ASSIGN_FALLBACK_SEQUENTIAL;
+import static timely.balancer.resolver.eventing.MetricAssignedEvent.Reason.ASSIGN_ROUND_ROBIN;
+import static timely.balancer.resolver.eventing.MetricAssignedEvent.Reason.HOST_DOWN_ROUND_ROBIN;
+import static timely.balancer.resolver.eventing.MetricAssignedEvent.Reason.HOST_REMOVED;
+import static timely.balancer.resolver.eventing.MetricAssignedEvent.Reason.REBALANCE;
 import static timely.store.cache.DataStoreCache.NON_CACHED_METRICS;
 import static timely.store.cache.DataStoreCache.NON_CACHED_METRICS_LOCK_PATH;
 
-import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -19,21 +23,18 @@ import java.util.List;
 import java.util.Map;
 import java.util.Random;
 import java.util.Set;
-import java.util.Timer;
-import java.util.TimerTask;
 import java.util.TreeMap;
 import java.util.TreeSet;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
-import com.csvreader.CsvReader;
-import com.csvreader.CsvWriter;
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.lang3.SerializationUtils;
 import org.apache.curator.framework.CuratorFramework;
-import org.apache.curator.framework.recipes.atomic.DistributedAtomicLong;
 import org.apache.curator.framework.recipes.atomic.DistributedAtomicValue;
 import org.apache.curator.framework.recipes.cache.TreeCache;
 import org.apache.curator.framework.recipes.cache.TreeCacheEvent;
@@ -48,11 +49,6 @@ import org.apache.curator.x.discovery.ServiceDiscovery;
 import org.apache.curator.x.discovery.ServiceDiscoveryBuilder;
 import org.apache.curator.x.discovery.ServiceInstance;
 import org.apache.curator.x.discovery.details.ServiceCacheListener;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.fs.FSDataInputStream;
-import org.apache.hadoop.fs.FSDataOutputStream;
-import org.apache.hadoop.fs.FileSystem;
-import org.apache.hadoop.fs.Path;
 import org.apache.zookeeper.CreateMode;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -61,69 +57,74 @@ import timely.balancer.ArrivalRate;
 import timely.balancer.configuration.BalancerConfiguration;
 import timely.balancer.connection.TimelyBalancedHost;
 import timely.balancer.healthcheck.HealthChecker;
+import timely.balancer.resolver.eventing.MetricAssignedCallback;
+import timely.balancer.resolver.eventing.MetricAssignedEvent;
+import timely.balancer.resolver.eventing.MetricBalanceCallback;
+import timely.balancer.resolver.eventing.MetricBalanceEvent;
+import timely.balancer.resolver.eventing.MetricHostCallback;
+import timely.balancer.resolver.eventing.MetricHostEvent;
 
 public class BalancedMetricResolver implements MetricResolver {
 
     private static final Logger LOG = LoggerFactory.getLogger(BalancedMetricResolver.class);
     private Map<String, TimelyBalancedHost> metricToHostMap = new TreeMap<>();
+    private Set<String> unassignedMetrics = new HashSet<>();
     private Map<String, ArrivalRate> metricMap = new HashMap<>();
     private ReentrantReadWriteLock balancerLock = new ReentrantReadWriteLock();
     private List<TimelyBalancedHost> serverList = new ArrayList<>();
     private Random r = new Random();
-    final private HealthChecker healthChecker;
-    private Timer timer = new Timer("RebalanceTimer", true);
-    private Timer arrivalRateTimer = new Timer("ArrivalRateTimerResolver", true);
+    private final HealthChecker healthChecker;
+    private ScheduledExecutorService assignmentExecutor = Executors.newScheduledThreadPool(2);
+    private ScheduledExecutorService arrivalRateExecutor = Executors.newScheduledThreadPool(2);
     private int roundRobinCounter = 0;
     private Set<String> nonCachedMetrics = new HashSet<>();
     private DistributedAtomicValue nonCachedMetricsIP;
     private ReentrantReadWriteLock nonCachedMetricsLocalLock = new ReentrantReadWriteLock();
     private InterProcessReadWriteLock nonCachedMetricsIPRWLock;
-    private BalancerConfiguration balancerConfig;
+    private AtomicLong assignmentsLastUpdatedLocal = new AtomicLong(0);
     private LeaderLatch leaderLatch;
     private AtomicBoolean isLeader = new AtomicBoolean(false);
     private InterProcessReadWriteLock assignmentsIPRWLock;
-    private DistributedAtomicLong assignmentsLastUpdatedInHdfs;
-    private AtomicLong assignmentsLastUpdatedLocal = new AtomicLong(0);
+    private MetricAssignmentPerister assignmentPerister;
 
-    private enum BalanceType {
-        HIGH_LOW, HIGH_AVG, AVG_LOW
+    final private BalancerConfiguration balancerConfig;
+    final private CuratorFramework curatorFramework;
+
+    private List<MetricAssignedCallback> metricAssignedCallbacks = new ArrayList<>();
+    private List<MetricBalanceCallback> metricBalanceCallbacks = new ArrayList<>();
+    private List<MetricHostCallback> metricHostCallbacks = new ArrayList<>();
+
+    public enum BalanceType {
+        HIGH_LOW, HIGH_AVG, AVG_LOW;
     }
 
     public BalancedMetricResolver(CuratorFramework curatorFramework, BalancerConfiguration balancerConfig,
             HealthChecker healthChecker) {
+        this.curatorFramework = curatorFramework;
         this.balancerConfig = balancerConfig;
         this.healthChecker = healthChecker;
+    }
 
+    public void start() {
         assignmentsIPRWLock = new InterProcessReadWriteLock(curatorFramework, ASSIGNMENTS_LOCK_PATH);
         testIPRWLock(curatorFramework, assignmentsIPRWLock, ASSIGNMENTS_LOCK_PATH);
+
+        this.assignmentPerister = new MetricAssignmentPerister(this, balancerConfig, metricToHostMap, nonCachedMetrics,
+                curatorFramework, assignmentsIPRWLock, nonCachedMetricsLocalLock, assignmentsLastUpdatedLocal,
+                balancerLock);
+
         startLeaderLatch(curatorFramework);
         startServiceListener(curatorFramework);
-        assignmentsLastUpdatedInHdfs = new DistributedAtomicLong(curatorFramework, ASSIGNMENTS_LAST_UPDATED_PATH,
-                new RetryForever(1000));
 
-        TreeCacheListener assignmentListener = new TreeCacheListener() {
-
-            @Override
-            public void childEvent(CuratorFramework curatorFramework, TreeCacheEvent event) throws Exception {
-                LOG.debug("Handling assignments event {}. assignmentsLastUpdatedInHdfs:{}", event.getType().toString(),
-                        new Date(assignmentsLastUpdatedInHdfs.get().postValue()));
-                if (event.getType().equals(TreeCacheEvent.Type.NODE_UPDATED)) {
-                    long lastLocalUpdate = assignmentsLastUpdatedLocal.get();
-                    long lastHdfsUpdate = assignmentsLastUpdatedInHdfs.get().postValue();
-                    if (lastHdfsUpdate > lastLocalUpdate) {
-                        LOG.debug("Reading assignments from hdfs lastHdfsUpdate ({}) > lastLocalUpdate ({})",
-                                new Date(lastHdfsUpdate), new Date(lastLocalUpdate));
-                        readAssignmentsFromHdfs();
-                    } else {
-                        LOG.debug("Not reading assignments from hdfs lastHdfsUpdate ({}) <= lastLocalUpdate ({})",
-                                new Date(lastHdfsUpdate), new Date(lastLocalUpdate));
-                    }
-                }
+        TreeCacheListener assignmentListener = (curatorFramework1, event) -> {
+            LOG.debug("Handling assignments event {}. assignmentsLastUpdated:{}", event.getType().toString(),
+                    new Date(assignmentPerister.getAssignmentsLastUpdatedByLeader()));
+            if (event.getType().equals(TreeCacheEvent.Type.NODE_UPDATED)) {
+                assignmentPerister.readAssignments(true);
             }
         };
 
-        try {
-            TreeCache assignmentTreeCache = new TreeCache(curatorFramework, ASSIGNMENTS_LAST_UPDATED_PATH);
+        try (TreeCache assignmentTreeCache = new TreeCache(curatorFramework, ASSIGNMENTS_LAST_UPDATED_PATH)) {
             assignmentTreeCache.getListenable().addListener(assignmentListener);
             assignmentTreeCache.start();
         } catch (Exception e) {
@@ -144,8 +145,7 @@ public class BalancedMetricResolver implements MetricResolver {
             }
         };
 
-        try {
-            TreeCache nonCachedMetricsTreeCache = new TreeCache(curatorFramework, NON_CACHED_METRICS);
+        try (TreeCache nonCachedMetricsTreeCache = new TreeCache(curatorFramework, NON_CACHED_METRICS)) {
             nonCachedMetricsTreeCache.getListenable().addListener(nonCachedMetricsListener);
             nonCachedMetricsTreeCache.start();
         } catch (Exception e) {
@@ -160,55 +160,55 @@ public class BalancedMetricResolver implements MetricResolver {
         }
         readNonCachedMetricsIP();
 
-        readAssignmentsFromHdfs();
+        assignmentPerister.readAssignments(false);
 
-        timer.schedule(new TimerTask() {
-
-            @Override
-            public void run() {
-                if (isLeader.get()) {
-                    try {
-                        balance();
-                    } catch (Exception e) {
-                        LOG.error(e.getMessage(), e);
-                    }
-                }
-            }
-        }, 900000, 900000);
-
-        timer.schedule(new TimerTask() {
-
-            @Override
-            public void run() {
+        assignmentExecutor.scheduleAtFixedRate(() -> {
+            if (isLeader.get()) {
                 try {
-                    if (isLeader.get()) {
-                        long lastLocalUpdate = assignmentsLastUpdatedLocal.get();
-                        long lastHdfsUpdate = assignmentsLastUpdatedInHdfs.get().postValue();
-                        if (lastLocalUpdate > lastHdfsUpdate) {
-                            LOG.debug("Writing assignments to hdfs lastLocalUpdate ({}) > lastHdfsUpdate ({})",
-                                    new Date(lastLocalUpdate), new Date(lastHdfsUpdate));
-                            writeAssigmentsToHdfs();
-                        }
-                    }
+                    balance();
                 } catch (Exception e) {
                     LOG.error(e.getMessage(), e);
                 }
             }
-        }, 10000, 60000);
+        }, balancerConfig.getBalanceDelay(), balancerConfig.getBalancePeriod(), TimeUnit.MILLISECONDS);
+
+        assignmentExecutor.scheduleAtFixedRate(() -> {
+            try {
+                if (isLeader.get()) {
+                    long lastLocalUpdate = assignmentsLastUpdatedLocal.get();
+                    long lastUpdateByLeader = assignmentPerister.getAssignmentsLastUpdatedByLeader();
+                    if (lastLocalUpdate > lastUpdateByLeader) {
+                        LOG.debug("Leader writing assignments lastLocalUpdate ({}) > lastUpdateByLeader ({})",
+                                new Date(lastLocalUpdate), new Date(lastUpdateByLeader));
+                        assignmentPerister.writeAssignments();
+                    } else {
+                        LOG.trace("Leader not writing assignments lastLocalUpdate ({}) <= lastUpdateByLeader ({})",
+                                new Date(lastLocalUpdate), new Date(lastUpdateByLeader));
+                    }
+                } else {
+                    assignmentPerister.readAssignments(true);
+                }
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
+        }, balancerConfig.getPersistDelay(), balancerConfig.getPersistPeriod(), TimeUnit.MILLISECONDS);
     }
 
     private void readNonCachedMetricsIP() {
 
         Set<String> currentNonCachedMetricsDistributed = new TreeSet<>();
         try {
-            nonCachedMetricsIPRWLock.readLock().acquire();
+            boolean acquired = false;
+            while (!acquired) {
+                acquired = nonCachedMetricsIPRWLock.readLock().acquire(60, TimeUnit.SECONDS);
+            }
             byte[] currentNonCachedMetricsDistributedBytes = nonCachedMetricsIP.get().postValue();
             if (currentNonCachedMetricsDistributedBytes != null) {
                 try {
                     currentNonCachedMetricsDistributed = SerializationUtils
                             .deserialize(currentNonCachedMetricsDistributedBytes);
                 } catch (Exception e) {
-                    LOG.error(e.getMessage());
+                    LOG.error(e.getMessage(), e);
                     currentNonCachedMetricsDistributed = new TreeSet<>();
                 }
             }
@@ -249,7 +249,7 @@ public class BalancedMetricResolver implements MetricResolver {
                 public void isLeader() {
                     LOG.info("this balancer is the leader");
                     isLeader.set(true);
-                    writeAssigmentsToHdfs();
+                    assignmentPerister.writeAssignments();
                 }
 
                 @Override
@@ -265,28 +265,29 @@ public class BalancedMetricResolver implements MetricResolver {
 
     private void startServiceListener(CuratorFramework curatorFramework) {
         try {
-            ServiceDiscovery discovery = ServiceDiscoveryBuilder.builder(ServerDetails.class).client(curatorFramework)
-                    .basePath(SERVICE_DISCOVERY_PATH).build();
+            ServiceDiscovery<ServerDetails> discovery = ServiceDiscoveryBuilder.builder(ServerDetails.class)
+                    .client(curatorFramework).basePath(SERVICE_DISCOVERY_PATH).build();
             discovery.start();
-            Collection<ServiceInstance> instances = discovery.queryForInstances("timely-server");
+            Collection<ServiceInstance<ServerDetails>> instances = discovery.queryForInstances("timely-server");
 
             balancerLock.writeLock().lock();
             try {
-                for (ServiceInstance si : instances) {
-                    ServerDetails pl = (ServerDetails) si.getPayload();
+                for (ServiceInstance<ServerDetails> si : instances) {
+                    ServerDetails pl = si.getPayload();
                     TimelyBalancedHost tbh = TimelyBalancedHost.of(pl.getHost(), pl.getTcpPort(), pl.getHttpPort(),
-                            pl.getWsPort(), pl.getUdpPort());
-                    LOG.info("adding service {} host:{} tcpPort:{} httpPort:{} wsPort:{} udpPort:{}", si.getId(),
-                            pl.getHost(), pl.getTcpPort(), pl.getHttpPort(), pl.getWsPort(), pl.getUdpPort());
+                            pl.getWsPort(), pl.getUdpPort(), new ArrivalRate(arrivalRateExecutor));
+                    LOG.info("adding service {} host:{}", si.getId(), TimelyBalancedHost.toStringShort(tbh));
                     tbh.setBalancerConfig(balancerConfig);
                     serverList.add(tbh);
+                    metricHostEvent(tbh, MetricHostEvent.ActionType.ADDED);
                 }
                 healthChecker.setTimelyHosts(serverList);
             } finally {
                 balancerLock.writeLock().unlock();
             }
 
-            final ServiceCache serviceCache = discovery.serviceCacheBuilder().name("timely-server").build();
+            final ServiceCache<ServerDetails> serviceCache = discovery.serviceCacheBuilder().name("timely-server")
+                    .build();
             ServiceCacheListener listener = new ServiceCacheListener() {
 
                 @Override
@@ -294,12 +295,13 @@ public class BalancedMetricResolver implements MetricResolver {
                     boolean rebalanceNeeded = false;
                     balancerLock.writeLock().lock();
                     try {
-                        List<ServiceInstance> instances = serviceCache.getInstances();
+                        List<ServiceInstance<ServerDetails>> instances = serviceCache.getInstances();
                         Set<TimelyBalancedHost> availableHosts = new HashSet<>();
-                        for (ServiceInstance si : instances) {
+                        for (ServiceInstance<ServerDetails> si : instances) {
                             ServerDetails pl = (ServerDetails) si.getPayload();
                             TimelyBalancedHost tbh = TimelyBalancedHost.of(pl.getHost(), pl.getTcpPort(),
-                                    pl.getHttpPort(), pl.getWsPort(), pl.getUdpPort());
+                                    pl.getHttpPort(), pl.getWsPort(), pl.getUdpPort(),
+                                    new ArrivalRate(arrivalRateExecutor));
                             tbh.setBalancerConfig(balancerConfig);
                             availableHosts.add(tbh);
                         }
@@ -313,9 +315,8 @@ public class BalancedMetricResolver implements MetricResolver {
                                 availableHosts.remove(h);
                             } else {
                                 itr.remove();
-                                LOG.info("removing service {}:{} host:{} tcpPort:{} httpPort:{} wsPort:{} udpPort:{}",
-                                        h.getHost(), h.getTcpPort(), h.getHost(), h.getTcpPort(), h.getHttpPort(),
-                                        h.getWsPort(), h.getUdpPort());
+                                metricHostEvent(h, MetricHostEvent.ActionType.REMOVED);
+                                LOG.info("removing service {}", TimelyBalancedHost.toStringShort(h));
                                 for (Map.Entry<String, TimelyBalancedHost> e : metricToHostMap.entrySet()) {
                                     if (e.getValue().equals(h)) {
                                         reassignMetrics.add(e.getKey());
@@ -327,28 +328,33 @@ public class BalancedMetricResolver implements MetricResolver {
 
                         // add new hosts that were not previously known
                         for (TimelyBalancedHost h : availableHosts) {
-                            LOG.info("adding service {}:{} host:{} tcpPort:{} httpPort:{} wsPort:{} udpPort:{}",
-                                    h.getHost(), h.getTcpPort(), h.getHost(), h.getTcpPort(), h.getHttpPort(),
-                                    h.getWsPort(), h.getUdpPort());
+                            LOG.info("adding service {}", TimelyBalancedHost.toStringShort(h));
                             serverList.add(h);
+                            metricHostEvent(h, MetricHostEvent.ActionType.ADDED);
                             rebalanceNeeded = true;
                         }
                         healthChecker.setTimelyHosts(serverList);
-
+                        if (!availableHosts.isEmpty()) {
+                            reassignMetrics.addAll(unassignedMetrics);
+                            unassignedMetrics.clear();
+                        }
                         if (isLeader.get()) {
                             for (String s : reassignMetrics) {
                                 TimelyBalancedHost h = getRoundRobinHost(null);
-                                assignMetric(s, h);
-                                LOG.debug("Assigned server removed.  Assigning {} to server {}:{}", s, h.getTcpPort());
+                                assignMetric(s, h, HOST_REMOVED);
+                                LOG.debug("Assigned server removed.  Assigning {} to server {}", s,
+                                        TimelyBalancedHost.toStringShort(h));
                             }
-                            writeAssigmentsToHdfs();
                         }
 
                     } finally {
                         balancerLock.writeLock().unlock();
                     }
-                    if (isLeader.get() && rebalanceNeeded) {
-                        balance();
+                    if (isLeader.get()) {
+                        if (rebalanceNeeded) {
+                            balance();
+                        }
+                        assignmentPerister.writeAssignments();
                     }
                 }
 
@@ -408,7 +414,7 @@ public class BalancedMetricResolver implements MetricResolver {
         return tbh;
     }
 
-    private TimelyBalancedHost getRoundRobinHost(TimelyBalancedHost notThisOne) {
+    protected TimelyBalancedHost getRoundRobinHost(TimelyBalancedHost notThisOne) {
         TimelyBalancedHost tbh = null;
         balancerLock.readLock().lock();
         try {
@@ -530,8 +536,10 @@ public class BalancedMetricResolver implements MetricResolver {
 
         int numReassigned = 0;
         if (isLeader.get()) {
+            metricBalanceEvent(MetricBalanceEvent.ProgressType.BEGIN, balanceType, 0);
             balancerLock.writeLock().lock();
             try {
+                metricBalanceEvent(MetricBalanceEvent.ProgressType.BALANCER_LOCK_ACQUIRED, balanceType, 0);
                 Map<String, ArrivalRate> tempMetricMap = new HashMap<>();
                 tempMetricMap.putAll(metricMap);
 
@@ -561,8 +569,8 @@ public class BalancedMetricResolver implements MetricResolver {
                         }
                     }
 
-                    LOG.trace("focusHost {}:{} desiredChange:{} rateSortedMetrics.size():{}", h.getHost(),
-                            h.getTcpPort(), desiredChange, rateSortedMetrics.size());
+                    LOG.trace("focusHost {} desiredChange:{} rateSortedMetrics.size():{}",
+                            TimelyBalancedHost.toStringShort(h), desiredChange, rateSortedMetrics.size());
 
                     boolean doneWithHost = false;
                     while (!doneWithHost) {
@@ -591,7 +599,7 @@ public class BalancedMetricResolver implements MetricResolver {
                                 } else {
                                     String metric = e.getValue();
                                     Double metricRate = e.getKey();
-                                    assignMetric(metric, candidateHost);
+                                    assignMetric(metric, candidateHost, REBALANCE);
                                     numReassigned++;
                                     calculatedRates.put(candidateHost, calculatedRates.get(candidateHost) + metricRate);
                                     calculatedRates.put(h, calculatedRates.get(h) - metricRate);
@@ -600,9 +608,9 @@ public class BalancedMetricResolver implements MetricResolver {
                                     itr.remove();
                                     tempMetricMap.remove(metric);
                                     LOG.info(
-                                            "rebalancing: reassigning metric:{} rate:{} from server {}:{} to {}:{} remaining delta {}",
-                                            metric, metricRate, h.getHost(), h.getTcpPort(), candidateHost.getHost(),
-                                            candidateHost.getTcpPort(), desiredChange);
+                                            "rebalancing: reassigning metric:{} rate:{} from server {} to {} remaining delta {}",
+                                            metric, metricRate, TimelyBalancedHost.toStringShort(h),
+                                            TimelyBalancedHost.toStringShort(candidateHost), desiredChange);
                                 }
                             }
                         }
@@ -625,6 +633,7 @@ public class BalancedMetricResolver implements MetricResolver {
                 }
             } finally {
                 balancerLock.writeLock().unlock();
+                metricBalanceEvent(MetricBalanceEvent.ProgressType.END, balanceType, numReassigned);
             }
         }
         return numReassigned;
@@ -642,7 +651,10 @@ public class BalancedMetricResolver implements MetricResolver {
                 }
 
                 try {
-                    nonCachedMetricsIPRWLock.writeLock().acquire();
+                    boolean acquired = false;
+                    while (!acquired) {
+                        acquired = nonCachedMetricsIPRWLock.writeLock().acquire(60, TimeUnit.SECONDS);
+                    }
                     byte[] currentNonCachedMetricsDistributedBytes = nonCachedMetricsIP.get().postValue();
                     Set<String> currentNonCachedMetricsIP;
                     if (currentNonCachedMetricsDistributedBytes == null) {
@@ -689,12 +701,12 @@ public class BalancedMetricResolver implements MetricResolver {
             try {
                 lock.writeLock().release();
             } catch (Exception e3) {
-                LOG.error(e3.getMessage());
+                LOG.error(e3.getMessage(), e3);
             }
         }
     }
 
-    private boolean shouldCache(String metricName) {
+    protected boolean shouldCache(String metricName) {
 
         if (StringUtils.isBlank(metricName)) {
             return false;
@@ -743,7 +755,7 @@ public class BalancedMetricResolver implements MetricResolver {
             if (chooseMetricSpecificHost) {
                 ArrivalRate rate = metricMap.get(metric);
                 if (rate == null) {
-                    rate = new ArrivalRate(arrivalRateTimer);
+                    rate = new ArrivalRate(arrivalRateExecutor);
                     if (!balancerLock.isWriteLockedByCurrentThread()) {
                         balancerLock.readLock().unlock();
                         balancerLock.writeLock().lock();
@@ -756,7 +768,7 @@ public class BalancedMetricResolver implements MetricResolver {
             }
 
             if (StringUtils.isBlank(metric)) {
-                tbh = getRandomHost(null);
+                tbh = getRoundRobinHost(null);
             } else {
                 tbh = metricToHostMap.get(metric);
                 if (tbh == null) {
@@ -765,17 +777,17 @@ public class BalancedMetricResolver implements MetricResolver {
                         balancerLock.readLock().unlock();
                         balancerLock.writeLock().lock();
                     }
-                    assignMetric(metric, tbh);
+                    assignMetric(metric, tbh, ASSIGN_ROUND_ROBIN);
                 } else if (!tbh.isUp()) {
                     TimelyBalancedHost oldTbh = tbh;
-                    tbh = getLeastUsedHost();
-                    LOG.debug("rebalancing from host that is down: reassigning metric {} from server {}:{} to {}:{}",
-                            metric, oldTbh.getHost(), oldTbh.getTcpPort(), tbh.getHost(), tbh.getTcpPort());
+                    tbh = getRoundRobinHost(oldTbh);
+                    LOG.debug("rebalancing from host that is down: reassigning metric {} from server {} to {}", metric,
+                            TimelyBalancedHost.toStringShort(oldTbh), TimelyBalancedHost.toStringShort(tbh));
                     if (!balancerLock.isWriteLockedByCurrentThread()) {
                         balancerLock.readLock().unlock();
                         balancerLock.writeLock().lock();
                     }
-                    assignMetric(metric, tbh);
+                    assignMetric(metric, tbh, HOST_DOWN_ROUND_ROBIN);
                 }
             }
 
@@ -792,7 +804,7 @@ public class BalancedMetricResolver implements MetricResolver {
                         balancerLock.readLock().unlock();
                         balancerLock.writeLock().lock();
                     }
-                    assignMetric(metric, tbh);
+                    assignMetric(metric, tbh, ASSIGN_FALLBACK_SEQUENTIAL);
                 }
             }
         } finally {
@@ -821,20 +833,23 @@ public class BalancedMetricResolver implements MetricResolver {
                 metric = null;
             }
 
-            if (tbh == null || !tbh.isUp()) {
-                for (int x = 0; tbh == null && x < serverList.size(); x++) {
-                    tbh = serverList.get(Math.abs(r.nextInt() & Integer.MAX_VALUE) % serverList.size());
-                    if (!tbh.isUp()) {
-                        tbh = null;
-                    }
+            if (tbh == null) {
+                tbh = getRoundRobinHost(null);
+                if (!balancerLock.isWriteLockedByCurrentThread()) {
+                    balancerLock.readLock().unlock();
+                    balancerLock.writeLock().lock();
                 }
-                if (tbh != null && StringUtils.isNotBlank(metric)) {
-                    if (!balancerLock.isWriteLockedByCurrentThread()) {
-                        balancerLock.readLock().unlock();
-                        balancerLock.writeLock().lock();
-                    }
-                    assignMetric(metric, tbh);
+                assignMetric(metric, tbh, ASSIGN_ROUND_ROBIN);
+            } else if (!tbh.isUp()) {
+                TimelyBalancedHost oldTbh = tbh;
+                tbh = getRoundRobinHost(oldTbh);
+                LOG.debug("rebalancing from host that is down: reassigning metric {} from server {} to {}", metric,
+                        TimelyBalancedHost.toStringShort(oldTbh), TimelyBalancedHost.toStringShort(tbh));
+                if (!balancerLock.isWriteLockedByCurrentThread()) {
+                    balancerLock.readLock().unlock();
+                    balancerLock.writeLock().lock();
                 }
+                assignMetric(metric, tbh, HOST_DOWN_ROUND_ROBIN);
             }
 
             // if all else fails
@@ -850,7 +865,7 @@ public class BalancedMetricResolver implements MetricResolver {
                         balancerLock.readLock().unlock();
                         balancerLock.writeLock().lock();
                     }
-                    assignMetric(metric, tbh);
+                    assignMetric(metric, tbh, ASSIGN_FALLBACK_SEQUENTIAL);
                 }
             }
         } finally {
@@ -863,7 +878,7 @@ public class BalancedMetricResolver implements MetricResolver {
         return tbh;
     }
 
-    private TimelyBalancedHost findHost(String host, int tcpPort) {
+    protected TimelyBalancedHost findHost(String host, int tcpPort) {
         TimelyBalancedHost tbh = null;
         for (TimelyBalancedHost h : serverList) {
             if (h.getHost().equals(host) && h.getTcpPort() == tcpPort) {
@@ -874,144 +889,100 @@ public class BalancedMetricResolver implements MetricResolver {
         return tbh;
     }
 
-    private void readAssignmentsFromHdfs() {
-
-        Map<String, TimelyBalancedHost> assignedMetricToHostMap = new TreeMap<>();
-        try {
-            assignmentsIPRWLock.readLock().acquire();
-            balancerLock.writeLock().lock();
-            Configuration configuration = new Configuration();
-            FileSystem fs = FileSystem.get(configuration);
-            Path assignmentFile = new Path(balancerConfig.getAssignmentFile());
-            FSDataInputStream iStream = fs.open(assignmentFile);
-
-            CsvReader reader = new CsvReader(iStream, ',', Charset.forName("UTF-8"));
-            reader.setUseTextQualifier(false);
-
-            // skip the headers
-            boolean success = true;
-            success = reader.readHeaders();
-
-            while (success) {
-                success = reader.readRecord();
-                String[] nextLine = reader.getValues();
-                if (nextLine.length >= 3) {
-                    String metric = nextLine[0];
-                    String host = nextLine[1];
-                    int tcpPort = Integer.parseInt(nextLine[2]);
-                    TimelyBalancedHost tbh = findHost(host, tcpPort);
-                    if (tbh == null) {
-                        tbh = getRoundRobinHost(null);
-                    } else {
-                        LOG.trace("Found assigment: {} to {}:{}", metric, host, tcpPort);
-                    }
-                    assignedMetricToHostMap.put(metric, tbh);
-                }
-            }
-
-            metricToHostMap.clear();
-            for (Map.Entry<String, TimelyBalancedHost> e : assignedMetricToHostMap.entrySet()) {
-                if (shouldCache(e.getKey())) {
-                    metricToHostMap.put(e.getKey(), e.getValue());
-                }
-            }
-
-            nonCachedMetricsLocalLock.readLock().lock();
-            try {
-                Iterator<Map.Entry<String, TimelyBalancedHost>> itr = metricToHostMap.entrySet().iterator();
-                while (itr.hasNext()) {
-                    Map.Entry<String, TimelyBalancedHost> e = itr.next();
-                    if (nonCachedMetrics.contains(e.getKey())) {
-                        itr.remove();
-                    }
-                }
-            } finally {
-                nonCachedMetricsLocalLock.readLock().unlock();
-            }
-            assignmentsLastUpdatedLocal.set(assignmentsLastUpdatedInHdfs.get().postValue());
-            LOG.info("Read {} assignments from hdfs lastHdfsUpdate = lastLocalUpdate ({})", metricToHostMap.size(),
-                    new Date(assignmentsLastUpdatedLocal.get()));
-        } catch (Exception e) {
-            LOG.error(e.getMessage(), e);
-        } finally {
-            balancerLock.writeLock().unlock();
-            try {
-                assignmentsIPRWLock.readLock().release();
-            } catch (Exception e) {
-                LOG.error(e.getMessage(), e);
-            }
-        }
-    }
-
-    private void writeAssigmentsToHdfs() {
-
-        CsvWriter writer = null;
-        try {
-            assignmentsIPRWLock.writeLock().acquire();
-            balancerLock.readLock().lock();
-            nonCachedMetricsLocalLock.readLock().lock();
-            try {
-                if (!metricToHostMap.isEmpty()) {
-                    Configuration configuration = new Configuration();
-                    FileSystem fs = FileSystem.get(configuration);
-                    Path assignmentFile = new Path(balancerConfig.getAssignmentFile());
-                    if (!fs.exists(assignmentFile.getParent())) {
-                        fs.mkdirs(assignmentFile.getParent());
-                    }
-                    FSDataOutputStream oStream = fs.create(assignmentFile, true);
-                    writer = new CsvWriter(oStream, ',', Charset.forName("UTF-8"));
-                    writer.setUseTextQualifier(false);
-                    writer.write("metric");
-                    writer.write("host");
-                    writer.write("tcpPort");
-                    writer.endRecord();
-                    for (Map.Entry<String, TimelyBalancedHost> e : metricToHostMap.entrySet()) {
-                        if (!nonCachedMetrics.contains(e.getKey())) {
-                            writer.write(e.getKey());
-                            writer.write(e.getValue().getHost());
-                            writer.write(Integer.toString(e.getValue().getTcpPort()));
-                            writer.endRecord();
-                            LOG.trace("Saving assigment: {} to {}:{}", e.getKey(), e.getValue().getHost(),
-                                    e.getValue().getTcpPort());
-                        }
-                    }
-
-                    long now = System.currentTimeMillis();
-                    assignmentsLastUpdatedLocal.set(now);
-                    assignmentsLastUpdatedInHdfs.trySet(now);
-                    if (!assignmentsLastUpdatedInHdfs.get().succeeded()) {
-                        assignmentsLastUpdatedInHdfs.forceSet(now);
-                    }
-                    LOG.debug("Wrote {} assignments to hdfs lastHdfsUpdate = lastLocalUpdate ({})",
-                            metricToHostMap.size(), new Date(assignmentsLastUpdatedLocal.get()));
-                }
-            } finally {
-                nonCachedMetricsLocalLock.readLock().unlock();
-                balancerLock.readLock().unlock();
-            }
-        } catch (Exception e) {
-            LOG.error(e.getMessage(), e);
-        } finally {
-            if (writer != null) {
-                writer.close();
-            }
-            try {
-                assignmentsIPRWLock.writeLock().release();
-            } catch (Exception e) {
-                LOG.error(e.getMessage(), e);
-            }
-        }
-    }
-
-    private void assignMetric(String metric, TimelyBalancedHost tbh) {
+    private void assignMetric(String metric, TimelyBalancedHost tbh, MetricAssignedEvent.Reason reason) {
         if (isLeader.get()) {
-            balancerLock.writeLock().lock();
-            try {
-                metricToHostMap.put(metric, tbh);
-                assignmentsLastUpdatedLocal.set(System.currentTimeMillis());
-            } finally {
-                balancerLock.writeLock().unlock();
+            if (StringUtils.isNotBlank(metric) && tbh != null) {
+                balancerLock.writeLock().lock();
+                try {
+                    metricAssignedEvent(metric, metricToHostMap.get(metric), tbh, reason);
+                    metricToHostMap.put(metric, tbh);
+                    assignmentsLastUpdatedLocal.set(System.currentTimeMillis());
+                } finally {
+                    balancerLock.writeLock().unlock();
+                }
+            } else {
+                unassignedMetrics.add(metric);
+                // Exception e = new IllegalStateException("Bad assignment metric:" + metric + "
+                // host:" + tbh);
+                LOG.warn("Bad assignment metric:" + metric + " host:" + tbh);
             }
         }
     }
+
+    public void registerCallback(MetricAssignedCallback callback) {
+        this.metricAssignedCallbacks.add(callback);
+    }
+
+    public void registerCallback(MetricBalanceCallback callback) {
+        this.metricBalanceCallbacks.add(callback);
+    }
+
+    public void registerCallback(MetricHostCallback callback) {
+        this.metricHostCallbacks.add(callback);
+    }
+
+    protected void metricAssignedEvent(String metric, TimelyBalancedHost losing, TimelyBalancedHost gaining,
+            MetricAssignedEvent.Reason reason) {
+        if (!metricAssignedCallbacks.isEmpty()) {
+            MetricAssignedEvent event = new MetricAssignedEvent(metric, losing, gaining, reason);
+            for (MetricAssignedCallback callback : metricAssignedCallbacks) {
+                callback.onEvent(event);
+            }
+        }
+    }
+
+    protected void metricBalanceEvent(MetricBalanceEvent.ProgressType progressType,
+            BalancedMetricResolver.BalanceType balanceType, long numReassigned) {
+        if (!metricBalanceCallbacks.isEmpty()) {
+            MetricBalanceEvent event = new MetricBalanceEvent(progressType, balanceType, numReassigned);
+            for (MetricBalanceCallback callback : metricBalanceCallbacks) {
+                callback.onEvent(event);
+            }
+        }
+    }
+
+    protected void metricHostEvent(TimelyBalancedHost host, MetricHostEvent.ActionType actionType) {
+        if (!metricHostCallbacks.isEmpty()) {
+            MetricHostEvent event = new MetricHostEvent(host, actionType);
+            for (MetricHostCallback callback : metricHostCallbacks) {
+                callback.onEvent(event);
+            }
+        }
+    }
+
+    protected void writeAssignments(Map<String, TimelyBalancedHost> metricToHostMap) {
+        assignmentPerister.writeAssignments(metricToHostMap);
+    }
+
+    @Override
+    public void stop() {
+
+        this.assignmentExecutor.shutdown();
+        try {
+            this.assignmentExecutor.awaitTermination(5, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+
+        } finally {
+            if (!this.assignmentExecutor.isTerminated()) {
+                this.assignmentExecutor.shutdownNow();
+            }
+        }
+
+        this.arrivalRateExecutor.shutdown();
+        try {
+            this.arrivalRateExecutor.awaitTermination(5, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+
+        } finally {
+            if (!this.arrivalRateExecutor.isTerminated()) {
+                this.arrivalRateExecutor.shutdownNow();
+            }
+        }
+
+        try {
+            this.healthChecker.close();
+        } catch (Exception e) {
+            LOG.error(e.getMessage(), e);
+        }
+    }
 }

balancer/src/main/java/timely/balancer/resolver/MetricAssignmentPerister.java

@@ -0,0 +1,320 @@
+package timely.balancer.resolver;
+
+import static timely.balancer.Balancer.ASSIGNMENTS_LAST_UPDATED_PATH;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.charset.Charset;
+import java.util.Date;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import com.csvreader.CsvReader;
+import com.csvreader.CsvWriter;
+import org.apache.commons.lang.StringUtils;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.recipes.atomic.DistributedAtomicLong;
+import org.apache.curator.framework.recipes.locks.InterProcessReadWriteLock;
+import org.apache.curator.retry.RetryForever;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import timely.balancer.configuration.BalancerConfiguration;
+import timely.balancer.connection.TimelyBalancedHost;
+import timely.balancer.resolver.eventing.MetricAssignedEvent;
+
+public class MetricAssignmentPerister {
+
+    private final Logger LOG = LoggerFactory.getLogger(getClass());
+
+    private enum PeristerType {
+        HDFS, FILE
+    }
+
+    // passed in through constructor
+    BalancedMetricResolver balancedMetricResolver;
+    private BalancerConfiguration balancerConfig;
+    private Map<String, TimelyBalancedHost> metricToHostMap;
+    private Set<String> nonCachedMetrics;
+    private InterProcessReadWriteLock assignmentsIPRWLock;
+    private ReentrantReadWriteLock nonCachedMetricsLocalLock;
+    private ReentrantReadWriteLock balancerLock;
+    private AtomicLong assignmentsLastUpdatedLocal;
+
+    // local
+    private DistributedAtomicLong assignmentsLastUpdatedInHdfs;
+
+    public MetricAssignmentPerister(BalancedMetricResolver balancedMetricResolver, BalancerConfiguration balancerConfig,
+            Map<String, TimelyBalancedHost> metricToHostMap, Set<String> nonCachedMetrics,
+            CuratorFramework curatorFramework, InterProcessReadWriteLock assignmentsIPRWLock,
+            ReentrantReadWriteLock nonCachedMetricsLocalLock, AtomicLong assignmentsLastUpdatedLocal,
+            ReentrantReadWriteLock balancerLock) {
+
+        this.balancedMetricResolver = balancedMetricResolver;
+        this.balancerConfig = balancerConfig;
+        this.metricToHostMap = metricToHostMap;
+        this.nonCachedMetrics = nonCachedMetrics;
+        this.assignmentsIPRWLock = assignmentsIPRWLock;
+        this.nonCachedMetricsLocalLock = nonCachedMetricsLocalLock;
+        this.assignmentsLastUpdatedLocal = assignmentsLastUpdatedLocal;
+        this.balancerLock = balancerLock;
+        assignmentsLastUpdatedInHdfs = new DistributedAtomicLong(curatorFramework, ASSIGNMENTS_LAST_UPDATED_PATH,
+                new RetryForever(1000));
+    }
+
+    public long getAssignmentsLastUpdatedByLeader() throws Exception {
+        return assignmentsLastUpdatedInHdfs.get().postValue();
+    }
+
+    public void readAssignments(boolean checkIfNecessary) {
+
+        try {
+            long lastLocalUpdate = assignmentsLastUpdatedLocal.get();
+            long lastHdfsUpdate = assignmentsLastUpdatedInHdfs.get().postValue();
+            if (checkIfNecessary) {
+                if (lastHdfsUpdate <= lastLocalUpdate) {
+                    LOG.debug("Not reading assignments from storage lastStorageUpdate ({}) <= lastLocalUpdate ({})",
+                            new Date(lastHdfsUpdate), new Date(lastLocalUpdate));
+                    return;
+                }
+            }
+            LOG.debug("Reading assignments from storage lastStorageUpdate ({}) > lastLocalUpdate ({})",
+                    new Date(lastHdfsUpdate), new Date(lastLocalUpdate));
+        } catch (Exception e) {
+            LOG.error(e.getMessage(), e);
+        }
+
+        // proceed with reading from storage
+
+        try (InputStream inputStream = getInputStream(balancerConfig)) {
+            boolean acquired = false;
+            while (!acquired) {
+                acquired = assignmentsIPRWLock.readLock().acquire(60, TimeUnit.SECONDS);
+            }
+            balancerLock.writeLock().lock();
+            // get potential new list from implementation
+            Map<String, TimelyBalancedHost> assignedMetricToHostMap = readFromStream(inputStream);
+            metricToHostMap.clear();
+            for (Map.Entry<String, TimelyBalancedHost> e : assignedMetricToHostMap.entrySet()) {
+                if (StringUtils.isNotBlank(e.getKey()) && e.getValue() != null) {
+                    if (balancedMetricResolver.shouldCache(e.getKey())) {
+                        balancedMetricResolver.metricAssignedEvent(e.getKey(), null, e.getValue(),
+                                MetricAssignedEvent.Reason.ASSIGN_FILE);
+                        metricToHostMap.put(e.getKey(), e.getValue());
+                    }
+                } else {
+                    Exception e1 = new IllegalStateException(
+                            "Bad assignment metric:" + e.getKey() + " host:" + e.getValue());
+                    LOG.warn(e1.getMessage(), e1);
+                }
+            }
+            nonCachedMetricsLocalLock.readLock().lock();
+            try {
+                Iterator<Map.Entry<String, TimelyBalancedHost>> itr = metricToHostMap.entrySet().iterator();
+                while (itr.hasNext()) {
+                    Map.Entry<String, TimelyBalancedHost> e = itr.next();
+                    if (nonCachedMetrics.contains(e.getKey())) {
+                        itr.remove();
+                    }
+                }
+            } finally {
+                nonCachedMetricsLocalLock.readLock().unlock();
+            }
+            assignmentsLastUpdatedLocal.set(assignmentsLastUpdatedInHdfs.get().postValue());
+            LOG.info("Read {} assignments from storage lastStorageUpdate = lastLocalUpdate ({})",
+                    metricToHostMap.size(), new Date(assignmentsLastUpdatedLocal.get()));
+        } catch (FileNotFoundException e) {
+            createAssignmentFile();
+            metricToHostMap.clear();
+        } catch (Exception e) {
+            LOG.error(e.getMessage(), e);
+        } finally {
+            balancerLock.writeLock().unlock();
+            try {
+                assignmentsIPRWLock.readLock().release();
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
+        }
+    }
+
+    public void writeAssignments() {
+        writeAssignments(metricToHostMap);
+    }
+
+    protected void writeAssignments(Map<String, TimelyBalancedHost> metricToHostMap) {
+
+        try {
+            boolean acquired = false;
+            while (!acquired) {
+                acquired = assignmentsIPRWLock.writeLock().acquire(60, TimeUnit.SECONDS);
+            }
+            balancerLock.readLock().lock();
+            nonCachedMetricsLocalLock.readLock().lock();
+            try (OutputStream outputStream = getOutputStream(balancerConfig)) {
+                if (!metricToHostMap.isEmpty()) {
+                    writeToStream(outputStream);
+                    long now = System.currentTimeMillis();
+                    assignmentsLastUpdatedLocal.set(now);
+                    assignmentsLastUpdatedInHdfs.trySet(now);
+                    if (!assignmentsLastUpdatedInHdfs.get().succeeded()) {
+                        assignmentsLastUpdatedInHdfs.forceSet(now);
+                    }
+                    LOG.debug("Wrote {} assignments to storage lastStorageUpdate = lastLocalUpdate ({})",
+                            metricToHostMap.size(), new Date(assignmentsLastUpdatedLocal.get()));
+                }
+            } finally {
+                nonCachedMetricsLocalLock.readLock().unlock();
+                balancerLock.readLock().unlock();
+            }
+        } catch (Exception e) {
+            LOG.error(e.getMessage(), e);
+        } finally {
+            try {
+                assignmentsIPRWLock.writeLock().release();
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
+        }
+    }
+
+    public Map<String, TimelyBalancedHost> readFromStream(InputStream inputStream) throws IOException {
+        Map<String, TimelyBalancedHost> assignedMetricToHostMap = new TreeMap<>();
+        try {
+            CsvReader reader = new CsvReader(inputStream, ',', Charset.forName("UTF-8"));
+            reader.setUseTextQualifier(false);
+
+            // skip the headers
+            boolean success = true;
+            success = reader.readHeaders();
+
+            while (success) {
+                success = reader.readRecord();
+                String[] nextLine = reader.getValues();
+                if (nextLine.length >= 3) {
+                    String metric = nextLine[0];
+                    String host = nextLine[1];
+                    int tcpPort = Integer.parseInt(nextLine[2]);
+                    TimelyBalancedHost tbh = balancedMetricResolver.findHost(host, tcpPort);
+                    if (tbh == null) {
+                        tbh = balancedMetricResolver.getRoundRobinHost(null);
+                    } else {
+                        LOG.trace("Found assigment: {} to {}:{}", metric, host, tcpPort);
+                    }
+                    assignedMetricToHostMap.put(metric, tbh);
+                }
+            }
+        } catch (IOException e) {
+            LOG.error(e.getMessage(), e);
+            throw e;
+        }
+        return assignedMetricToHostMap;
+    }
+
+    private void writeToStream(OutputStream outputStream) throws IOException {
+
+        CsvWriter writer = null;
+        try {
+            writer = new CsvWriter(outputStream, ',', Charset.forName("UTF-8"));
+            writer.setUseTextQualifier(false);
+            writer.write("metric");
+            writer.write("host");
+            writer.write("tcpPort");
+            writer.endRecord();
+            for (Map.Entry<String, TimelyBalancedHost> e : metricToHostMap.entrySet()) {
+                if (!nonCachedMetrics.contains(e.getKey())) {
+                    writer.write(e.getKey());
+                    writer.write(e.getValue().getHost());
+                    writer.write(Integer.toString(e.getValue().getTcpPort()));
+                    writer.endRecord();
+                    LOG.trace("Saving assigment: {} to {}:{}", e.getKey(), e.getValue().getHost(),
+                            e.getValue().getTcpPort());
+                }
+            }
+        } finally {
+            if (writer != null) {
+                writer.close();
+            }
+        }
+    }
+
+    public void createAssignmentFile() {
+        LOG.info("Creating assignment file: " + balancerConfig.getAssignmentFile());
+        PeristerType peristerType = PeristerType.valueOf(balancerConfig.getMetricAssignmentPersisterType());
+        switch (peristerType) {
+            case HDFS:
+                try {
+                    Configuration configuration = new Configuration();
+                    FileSystem fs = FileSystem.get(configuration);
+                    Path assignmentFile = new Path(balancerConfig.getAssignmentFile());
+                    fs.create(assignmentFile);
+                } catch (Exception e) {
+                    LOG.error(e.getMessage(), e);
+                }
+                break;
+            case FILE:
+                try {
+                    File assignmentFile = new File(balancerConfig.getAssignmentFile());
+                    String parentPath = assignmentFile.getParent();
+                    File directory = new File(parentPath);
+                    if (!directory.exists()) {
+
+                        directory.mkdirs();
+                    }
+                    if (!assignmentFile.exists()) {
+                        assignmentFile.createNewFile();
+                    }
+                } catch (Exception e) {
+                    LOG.error(e.getMessage(), e);
+                }
+                break;
+        }
+    }
+
+    public InputStream getInputStream(BalancerConfiguration balancerConfiguration) throws Exception {
+        PeristerType peristerType = PeristerType.valueOf(balancerConfiguration.getMetricAssignmentPersisterType());
+        switch (peristerType) {
+            case HDFS:
+                Configuration configuration = new Configuration();
+                FileSystem fs = FileSystem.get(configuration);
+                Path assignmentFile = new Path(balancerConfiguration.getAssignmentFile());
+                return fs.open(assignmentFile);
+            case FILE:
+                return new FileInputStream(new File(balancerConfiguration.getAssignmentFile()));
+            default:
+                throw new IllegalArgumentException(
+                        "Unknown metricPersisterType " + balancerConfiguration.getMetricAssignmentPersisterType());
+        }
+    }
+
+    public OutputStream getOutputStream(BalancerConfiguration balancerConfiguration) throws IOException {
+        PeristerType peristerType = PeristerType.valueOf(balancerConfiguration.getMetricAssignmentPersisterType());
+        switch (peristerType) {
+            case HDFS:
+                Configuration configuration = new Configuration();
+                FileSystem fs = FileSystem.get(configuration);
+                Path assignmentFile = new Path(balancerConfiguration.getAssignmentFile());
+                if (!fs.exists(assignmentFile.getParent())) {
+                    fs.mkdirs(assignmentFile.getParent());
+                }
+                return fs.create(assignmentFile, true);
+            case FILE:
+                return new FileOutputStream(new File(balancerConfiguration.getAssignmentFile()));
+            default:
+                throw new IllegalArgumentException(
+                        "Unknown metricPersisterType " + balancerConfiguration.getMetricAssignmentPersisterType());
+        }
+    }
+}

balancer/src/main/java/timely/balancer/resolver/MetricResolver.java

@@ -7,4 +7,9 @@ public interface MetricResolver {
     public TimelyBalancedHost getHostPortKeyIngest(String metric);
 
     public TimelyBalancedHost getHostPortKey(String metric);
+
+    public void start();
+
+    public void stop();
+
 }

balancer/src/main/java/timely/balancer/resolver/eventing/MetricAssignedCallback.java

@@ -0,0 +1,7 @@
+package timely.balancer.resolver.eventing;
+
+public abstract class MetricAssignedCallback {
+
+    public abstract void onEvent(MetricAssignedEvent event);
+
+}

balancer/src/main/java/timely/balancer/resolver/eventing/MetricAssignedEvent.java

@@ -0,0 +1,39 @@
+package timely.balancer.resolver.eventing;
+
+import timely.balancer.connection.TimelyBalancedHost;
+
+public class MetricAssignedEvent {
+
+    public enum Reason {
+        ASSIGN_ROUND_ROBIN, HOST_DOWN_ROUND_ROBIN, ASSIGN_FALLBACK_SEQUENTIAL, HOST_REMOVED, REBALANCE, ASSIGN_FILE
+    }
+
+    private final String metric;
+    private final TimelyBalancedHost losingHost;
+    private final TimelyBalancedHost gainingHost;
+    private final Reason reason;
+
+    public MetricAssignedEvent(String metric, TimelyBalancedHost losingHost, TimelyBalancedHost gainingHost,
+            Reason reason) {
+        this.metric = metric;
+        this.losingHost = losingHost;
+        this.gainingHost = gainingHost;
+        this.reason = reason;
+    }
+
+    public String getMetric() {
+        return metric;
+    }
+
+    public TimelyBalancedHost getLosingHost() {
+        return losingHost;
+    }
+
+    public TimelyBalancedHost getGainingHost() {
+        return gainingHost;
+    }
+
+    public Reason getReason() {
+        return reason;
+    }
+}

balancer/src/main/java/timely/balancer/resolver/eventing/MetricBalanceCallback.java

@@ -0,0 +1,7 @@
+package timely.balancer.resolver.eventing;
+
+public abstract class MetricBalanceCallback {
+
+    public abstract void onEvent(MetricBalanceEvent event);
+
+}

balancer/src/main/java/timely/balancer/resolver/eventing/MetricBalanceEvent.java

@@ -0,0 +1,33 @@
+package timely.balancer.resolver.eventing;
+
+import timely.balancer.resolver.BalancedMetricResolver;
+
+public class MetricBalanceEvent {
+
+    public enum ProgressType {
+        BEGIN, BALANCER_LOCK_ACQUIRED, END
+    }
+
+    private final ProgressType progressType;
+    private final BalancedMetricResolver.BalanceType balanceType;
+    private final Long numRessigned;
+
+    public MetricBalanceEvent(ProgressType progressType, BalancedMetricResolver.BalanceType balanceType,
+            long numReassigned) {
+        this.progressType = progressType;
+        this.balanceType = balanceType;
+        this.numRessigned = numReassigned;
+    }
+
+    public BalancedMetricResolver.BalanceType getBalanceType() {
+        return balanceType;
+    }
+
+    public ProgressType getProgressType() {
+        return progressType;
+    }
+
+    public Long getNumRessigned() {
+        return numRessigned;
+    }
+}

balancer/src/main/java/timely/balancer/resolver/eventing/MetricHostCallback.java

@@ -0,0 +1,7 @@
+package timely.balancer.resolver.eventing;
+
+public abstract class MetricHostCallback {
+
+    public abstract void onEvent(MetricHostEvent event);
+
+}

balancer/src/main/java/timely/balancer/resolver/eventing/MetricHostEvent.java

@@ -0,0 +1,26 @@
+package timely.balancer.resolver.eventing;
+
+import timely.balancer.connection.TimelyBalancedHost;
+
+public class MetricHostEvent {
+
+    public enum ActionType {
+        ADDED, REMOVED, SUCCESS, FAILURE
+    }
+
+    private final TimelyBalancedHost timelyBalancedHost;
+    private final ActionType actionType;
+
+    public MetricHostEvent(TimelyBalancedHost timelyBalancedHost, ActionType actionType) {
+        this.timelyBalancedHost = timelyBalancedHost;
+        this.actionType = actionType;
+    }
+
+    public TimelyBalancedHost getTimelyBalancedHost() {
+        return timelyBalancedHost;
+    }
+
+    public ActionType getActionType() {
+        return actionType;
+    }
+}

balancer/src/main/spotbugs/excludes.xml

@@ -10,4 +10,9 @@
     <Method name="getBuf" />
     <Bug pattern="EI_EXPOSE_REP" />
   </Match>
+  <Match>
+    <Class name="timely.balancer.resolver.MetricAssignmentPerister" />
+    <Method name="createAssignmentFile" />
+    <Bug pattern="RV_RETURN_VALUE_IGNORED_BAD_PRACTICE" />
+  </Match>
 </FindBugsFilter>

balancer/src/test/java/timely/balancer/resolver/ServiceRegistry.java

@@ -0,0 +1,76 @@
+package timely.balancer.resolver;
+
+import static timely.Server.SERVICE_DISCOVERY_PATH;
+
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.x.discovery.ServiceDiscovery;
+import org.apache.curator.x.discovery.ServiceDiscoveryBuilder;
+import org.apache.curator.x.discovery.ServiceInstance;
+import org.apache.curator.x.discovery.ServiceInstanceBuilder;
+import org.apache.zookeeper.data.Stat;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import timely.ServerDetails;
+import timely.balancer.connection.TimelyBalancedHost;
+
+public class ServiceRegistry {
+
+    private static final Logger LOG = LoggerFactory.getLogger(ServiceRegistry.class);
+
+    public static void registerService(CuratorFramework curatorFramework, TimelyBalancedHost tbh) {
+        try {
+            try {
+                Stat stat = curatorFramework.checkExists().forPath(SERVICE_DISCOVERY_PATH);
+                if (stat == null) {
+                    curatorFramework.create().creatingParentContainersIfNeeded().forPath(SERVICE_DISCOVERY_PATH);
+                }
+            } catch (Exception e) {
+                LOG.error(e.getMessage());
+            }
+
+            ServiceInstance<ServerDetails> serviceInstance = serviceInstance(tbh);
+            ServiceDiscovery<ServerDetails> discovery = ServiceDiscoveryBuilder.builder(ServerDetails.class)
+                    .client(curatorFramework).basePath(SERVICE_DISCOVERY_PATH).build();
+            discovery.start();
+            discovery.registerService(serviceInstance);
+        } catch (Exception e) {
+            LOG.error(e.getMessage());
+        }
+    }
+
+    public static void unregisterService(CuratorFramework curatorFramework, TimelyBalancedHost tbh) {
+        try {
+            try {
+                Stat stat = curatorFramework.checkExists().forPath(SERVICE_DISCOVERY_PATH);
+                if (stat == null) {
+                    curatorFramework.create().creatingParentContainersIfNeeded().forPath(SERVICE_DISCOVERY_PATH);
+                }
+            } catch (Exception e) {
+                LOG.error(e.getMessage());
+            }
+
+            ServiceInstance<ServerDetails> serviceInstance = serviceInstance(tbh);
+            ServiceDiscovery<ServerDetails> discovery = ServiceDiscoveryBuilder.builder(ServerDetails.class)
+                    .client(curatorFramework).basePath(SERVICE_DISCOVERY_PATH).build();
+            discovery.start();
+            discovery.unregisterService(serviceInstance);
+        } catch (Exception e) {
+            LOG.error(e.getMessage());
+        }
+    }
+
+    private static ServiceInstance<ServerDetails> serviceInstance(TimelyBalancedHost config) throws Exception {
+        ServerDetails serverDetails = new ServerDetails();
+        serverDetails.setHost(config.getHost());
+        serverDetails.setTcpPort(config.getTcpPort());
+        serverDetails.setHttpPort(config.getHttpPort());
+        serverDetails.setWsPort(config.getWsPort());
+        serverDetails.setUdpPort(config.getUdpPort());
+
+        ServiceInstanceBuilder<ServerDetails> builder = ServiceInstance.builder();
+        String serviceName = config.getHost() + ":" + config.getTcpPort();
+        ServiceInstance<ServerDetails> serviceInstance = builder.id(serviceName).name("timely-server")
+                .address(config.getHost()).port(config.getTcpPort()).payload(serverDetails).build();
+        return serviceInstance;
+    }
+}

balancer/src/test/java/timely/balancer/resolver/TestBalancedMetricResolver.java

@@ -0,0 +1,270 @@
+package timely.balancer.resolver;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.Random;
+import java.util.UUID;
+
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.CuratorFrameworkFactory;
+import org.apache.curator.retry.RetryNTimes;
+import org.apache.zookeeper.server.ServerConfig;
+import org.apache.zookeeper.server.ZooKeeperServerMain;
+import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.util.SocketUtils;
+import timely.balancer.configuration.BalancerConfiguration;
+import timely.balancer.connection.TimelyBalancedHost;
+import timely.balancer.resolver.eventing.MetricAssignedCallback;
+import timely.balancer.resolver.eventing.MetricAssignedEvent;
+import timely.balancer.resolver.eventing.MetricBalanceCallback;
+import timely.balancer.resolver.eventing.MetricBalanceEvent;
+import timely.balancer.resolver.eventing.MetricHostCallback;
+import timely.balancer.resolver.eventing.MetricHostEvent;
+
+public class TestBalancedMetricResolver {
+
+    private final Logger LOG = LoggerFactory.getLogger(getClass());
+    private CuratorFramework curatorFramework;
+    private SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd HHmmss.SSS");
+    private Random r = new Random(System.currentTimeMillis());
+    private List<TimelyBalancedHost> timelyHosts;
+    private Map<MetricAssignedEvent, Integer> metricBalanceEventCounter = new HashMap<>();
+
+    @Before
+    public void startup() {
+        QuorumPeerConfig currentConfig = createZookeeper();
+        InetSocketAddress address = currentConfig.getClientPortAddress();
+        String zkServer = address.getHostName() + ":" + address.getPort();
+        curatorFramework = CuratorFrameworkFactory.newClient(zkServer, 1000, 5000, new RetryNTimes(2, 50));
+        curatorFramework.start();
+        timelyHosts = new ArrayList<>();
+    }
+
+    @After
+    public void shutdown() {
+        curatorFramework.close();
+    }
+
+    private QuorumPeerConfig createZookeeper() {
+        Properties startupProperties = new Properties();
+        File file = new File(System.getProperty("java.io.tmpdir") + File.separator + UUID.randomUUID());
+        file.deleteOnExit();
+        startupProperties.setProperty("dataDir", file.getAbsolutePath());
+        startupProperties.setProperty("clientPort", String.valueOf(SocketUtils.findAvailableTcpPort(3000, 4000)));
+        QuorumPeerConfig quorumConfiguration = new QuorumPeerConfig();
+
+        try {
+            quorumConfiguration.parseProperties(startupProperties);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+
+        ZooKeeperServerMain zooKeeperServer = new ZooKeeperServerMain();
+        final ServerConfig configuration = new ServerConfig();
+        configuration.readFrom(quorumConfiguration);
+
+        new Thread() {
+
+            public void run() {
+                try {
+                    zooKeeperServer.runFromConfig(configuration);
+                } catch (IOException e) {
+                    LOG.error("ZooKeeper Failed", e);
+                }
+            }
+        }.start();
+
+        return quorumConfiguration;
+    }
+
+    private BalancerConfiguration getBalancerConfiguration() {
+        BalancerConfiguration balancerConfiguration = new BalancerConfiguration();
+        balancerConfiguration.setMetricAssignmentPersisterType("FILE");
+        File file = new File(System.getProperty("java.io.tmpdir") + File.separator + UUID.randomUUID());
+        file.deleteOnExit();
+        balancerConfiguration.setAssignmentFile(file.getAbsolutePath());
+        balancerConfiguration.setBalanceDelay(0);
+        balancerConfiguration.setBalancePeriod(1000);
+        balancerConfiguration.setPersistDelay(0);
+        balancerConfiguration.setPersistDelay(1000);
+        balancerConfiguration.setCheckServerHealthInterval(10);
+        return balancerConfiguration;
+    }
+
+    private void createTimelyHosts(BalancerConfiguration balancerConfiguration, int numHosts) {
+        for (int port = 1000, x = 0; x < numHosts; x++, port += 10) {
+            TimelyBalancedHost tbh = TimelyBalancedHost.of("localhost", port);
+            tbh.setBalancerConfig(balancerConfiguration);
+            timelyHosts.add(tbh);
+            ServiceRegistry.registerService(curatorFramework, tbh);
+        }
+    }
+
+    private void registerCallbacks(BalancedMetricResolver resolver) {
+        resolver.registerCallback(new MetricAssignedCallback() {
+
+            @Override
+            public void onEvent(MetricAssignedEvent event) {
+                LOG.debug(String.format("%s metric:%s lose:%s:%d gain:%s:%d reason:%s",
+                        event.getClass().getSimpleName(), event.getMetric(),
+                        event.getLosingHost() == null ? null : event.getLosingHost().getHost(),
+                        event.getLosingHost() == null ? null : event.getLosingHost().getTcpPort(),
+                        event.getGainingHost().getHost(), event.getGainingHost().getTcpPort(), event.getReason()));
+            }
+        });
+
+        resolver.registerCallback(new MetricHostCallback() {
+
+            @Override
+            public void onEvent(MetricHostEvent event) {
+                LOG.debug(String.format("%s host:%s:%d type:%s", event.getClass().getSimpleName(),
+                        event.getTimelyBalancedHost().getHost(), event.getTimelyBalancedHost().getTcpPort(),
+                        event.getActionType()));
+            }
+        });
+
+        resolver.registerCallback(new MetricBalanceCallback() {
+
+            @Override
+            public void onEvent(MetricBalanceEvent event) {
+                LOG.debug(String.format("%s type:%s progress:%s reassigned:%d", event.getClass().getSimpleName(),
+                        event.getBalanceType(), event.getProgressType(), event.getNumRessigned()));
+            }
+        });
+    }
+
+    private TimelyBalancedHost randomServerDown(TestHealthChecker healthChecker, int numHosts) {
+        TimelyBalancedHost tbh = timelyHosts.get(r.nextInt(numHosts));
+        LOG.debug("Marking server down:" + TimelyBalancedHost.toStringShort(tbh));
+        healthChecker.serverDown(tbh);
+        return tbh;
+    }
+
+    private TimelyBalancedHost randomServerToggle(TestHealthChecker healthChecker, int numHosts) {
+        TimelyBalancedHost tbh = timelyHosts.get(r.nextInt(numHosts));
+        LOG.debug("Marking server " + (tbh.isUp() ? "down:" : "up:") + TimelyBalancedHost.toStringShort(tbh));
+        healthChecker.serverToggle(tbh);
+        return tbh;
+    }
+
+    private TimelyBalancedHost randomServerUnregister(int numHosts) {
+        TimelyBalancedHost tbh = timelyHosts.get(r.nextInt(numHosts));
+        LOG.debug("Unregistering:" + TimelyBalancedHost.toStringShort(tbh));
+        ServiceRegistry.unregisterService(curatorFramework, tbh);
+        return tbh;
+    }
+
+    @Test
+    public void test1() {
+        LOG.debug("Configure test");
+        int numHosts = 10;
+        BalancerConfiguration balancerConfiguration = getBalancerConfiguration();
+        createTimelyHosts(balancerConfiguration, numHosts);
+        TestHealthChecker healthChecker = new TestHealthChecker(balancerConfiguration, timelyHosts);
+        BalancedMetricResolver balancedMetricResolver = new BalancedMetricResolver(curatorFramework,
+                balancerConfiguration, healthChecker);
+        registerCallbacks(balancedMetricResolver);
+        LOG.debug("Start balancedMetricResolver");
+        balancedMetricResolver.start();
+        long now = System.currentTimeMillis();
+        int numMetrics = 100;
+        for (int x = 0; x < numMetrics; x++) {
+            balancedMetricResolver.getHostPortKeyIngest(String.format("metric%03d", x));
+        }
+
+        LOG.debug("Begin monitoring");
+        long cycle = 0;
+        List<TimelyBalancedHost> serversUnregistered = new ArrayList<>();
+        while (System.currentTimeMillis() < now + 15000) {
+            try {
+                Thread.sleep(100);
+                for (int x = 0; x < 10000; x++) {
+                    int mNum = r.nextInt(numMetrics);
+                    balancedMetricResolver.getHostPortKeyIngest(String.format("metric%03d", mNum));
+                }
+                // if (cycle % 100 == 0) {
+                // randomServerDown(healthChecker, numHosts);
+                // }
+                // if (cycle % 2 == 0) {
+                // randomServerToggle(healthChecker, numHosts);
+                // }
+                if (cycle % 100 == 0) {
+                    serversUnregistered.add(randomServerUnregister(numHosts));
+                }
+                if (cycle % 500 == 0) {
+                    serversUnregistered.stream().forEach(tbh -> ServiceRegistry.registerService(curatorFramework, tbh));
+                    serversUnregistered.clear();
+                }
+
+            } catch (InterruptedException e) {
+
+            }
+            cycle++;
+        }
+        LOG.debug("Stop balancedMetricResolver");
+        balancedMetricResolver.stop();
+    }
+
+    @Test
+    public void test2() {
+        LOG.debug("Configure test");
+        int numHosts = 10;
+        BalancerConfiguration balancerConfiguration = getBalancerConfiguration();
+        createTimelyHosts(balancerConfiguration, numHosts);
+        TestHealthChecker healthChecker = new TestHealthChecker(balancerConfiguration, timelyHosts);
+        BalancedMetricResolver balancedMetricResolver = new BalancedMetricResolver(curatorFramework,
+                balancerConfiguration, healthChecker);
+        registerCallbacks(balancedMetricResolver);
+        LOG.debug("Start balancedMetricResolver");
+        balancedMetricResolver.start();
+        long now = System.currentTimeMillis();
+        int numMetrics = 100;
+        for (int x = 0; x < numMetrics; x++) {
+            balancedMetricResolver.getHostPortKeyIngest(String.format("metric%03d", x));
+        }
+
+        LOG.debug("Begin monitoring");
+        long cycle = 0;
+        List<TimelyBalancedHost> serversUnregistered = new ArrayList<>();
+        while (System.currentTimeMillis() < now + 15000) {
+            try {
+                Thread.sleep(100);
+                for (int x = 0; x < 10000; x++) {
+                    int mNum = r.nextInt(numMetrics);
+                    balancedMetricResolver.getHostPortKeyIngest(String.format("metric%03d", mNum));
+                }
+                // if (cycle % 100 == 0) {
+                // randomServerDown(healthChecker, numHosts);
+                // }
+                // if (cycle % 2 == 0) {
+                // randomServerToggle(healthChecker, numHosts);
+                // }
+                if (cycle % 100 == 0) {
+                    serversUnregistered.add(randomServerUnregister(numHosts));
+                }
+                if (cycle % 500 == 0) {
+                    serversUnregistered.stream().forEach(tbh -> ServiceRegistry.registerService(curatorFramework, tbh));
+                    serversUnregistered.clear();
+                }
+
+            } catch (InterruptedException e) {
+
+            }
+            cycle++;
+        }
+        LOG.debug("Stop balancedMetricResolver");
+        balancedMetricResolver.stop();
+    }
+}

balancer/src/test/java/timely/balancer/resolver/TestHealthChecker.java

@@ -0,0 +1,89 @@
+package timely.balancer.resolver;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import timely.balancer.configuration.BalancerConfiguration;
+import timely.balancer.connection.TimelyBalancedHost;
+import timely.balancer.healthcheck.HealthChecker;
+import timely.balancer.healthcheck.TcpHealthChecker;
+
+public class TestHealthChecker implements HealthChecker {
+
+    private final Logger LOG = LoggerFactory.getLogger(TcpHealthChecker.class);
+    private List<TimelyBalancedHost> timelyHosts = new ArrayList<>();
+    private Map<TimelyBalancedHost, Boolean> serverUpMap = Collections.synchronizedMap(new HashMap<>());
+    private ScheduledExecutorService executorService = Executors.newScheduledThreadPool(1);
+
+    public TestHealthChecker(BalancerConfiguration config, List<TimelyBalancedHost> timelyHosts) {
+        setTimelyHosts(timelyHosts);
+        this.executorService.scheduleAtFixedRate(() -> {
+            synchronized (timelyHosts) {
+                for (TimelyBalancedHost h : timelyHosts) {
+                    try {
+                        if (TestHealthChecker.this.isServerHealthy(h)) {
+                            h.reportSuccess();
+                        } else {
+                            h.reportFailure();
+                        }
+                    } catch (Exception e) {
+                        LOG.error(e.getMessage(), e);
+                        h.reportFailure();
+                    }
+                }
+            }
+        }, 0, config.getCheckServerHealthInterval(), TimeUnit.MILLISECONDS);
+    }
+
+    @Override
+    public void setTimelyHosts(List<TimelyBalancedHost> timelyHosts) {
+        synchronized (timelyHosts) {
+            this.timelyHosts.clear();
+            this.timelyHosts.addAll(timelyHosts);
+            for (TimelyBalancedHost h : timelyHosts) {
+                serverUpMap.put(h, true);
+            }
+        }
+
+    }
+
+    public boolean isServerHealthy(TimelyBalancedHost h) {
+        return serverUpMap.get(h);
+    }
+
+    public void serverUp(TimelyBalancedHost h) {
+        serverUpMap.put(h, true);
+    }
+
+    public void serverDown(TimelyBalancedHost h) {
+        serverUpMap.put(h, false);
+    }
+
+    public void serverToggle(TimelyBalancedHost h) {
+        synchronized (serverUpMap) {
+            serverUpMap.put(h, !serverUpMap.get(h));
+        }
+    }
+
+    @Override
+    public void close() throws Exception {
+        this.executorService.shutdown();
+        try {
+            this.executorService.awaitTermination(5, TimeUnit.SECONDS);
+        } catch (InterruptedException e) {
+
+        } finally {
+            if (!this.executorService.isTerminated()) {
+                this.executorService.shutdownNow();
+            }
+        }
+    }
+}

balancer/src/test/resources/log4j2.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Configuration status="WARN">
+  <Appenders>
+    <Console name="CONSOLE" target="SYSTEM_OUT">
+      <PatternLayout pattern="%d{yyyyMMdd HHmmss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
+    </Console>
+  </Appenders>
+  <Loggers>
+    <Logger name="org.apache.accumulo.core.client.impl.ThriftTransportPool" level="OFF" additivity="false" />
+    <Logger name="org.apache.accumulo.fate.zookeeper.ZooCache" level="OFF" additivity="false" />
+    <Logger name="org.apache.zookeeper" level="OFF" additivity="false" />
+    <Logger name="timely.balancer.resolver" level="TRACE" additivity="true" />
+    <Logger name="timely.balancer.resolver.TestBalancedMetricResolver" level="DEBUG" additivity="true" />
+    <Root level="ERROR">
+      <AppenderRef ref="CONSOLE"/>
+    </Root>
+  </Loggers>
+</Configuration>

client/pom.xml

@@ -4,12 +4,13 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>timely-client</artifactId>
   <properties>
     <!-- PEP 440 compliant version gets substituted into src/main/python/template/setup.py -->
-    <python.client.version>1.2.3</python.client.version>
+    <!-- use .dev0 instead of -SNAPSHOT -->
+    <python.client.version>1.2.8.dev0</python.client.version>
   </properties>
   <dependencies>
     <dependency>

client/src/main/java/timely/client/tcp/TcpClient.java

@@ -1,7 +1,8 @@
 package timely.client.tcp;
 
+import java.io.BufferedWriter;
 import java.io.IOException;
-import java.io.PrintWriter;
+import java.io.OutputStreamWriter;
 import java.net.Socket;
 
 import org.slf4j.Logger;
@@ -14,7 +15,7 @@ public class TcpClient implements AutoCloseable {
     private final String host;
     private final int port;
     private Socket sock = null;
-    private PrintWriter out = null;
+    private BufferedWriter out = null;
     private long connectTime = 0L;
     private long backoff = 2000;
     private int bufferSize = -1;
@@ -47,7 +48,6 @@ public class TcpClient implements AutoCloseable {
      * 
      * @param metric
      *            newline terminated string representation of Timely metric
-     * @throws IOException
      */
     public synchronized void write(String metric) throws IOException {
         if (connect() != 0) {
@@ -60,7 +60,7 @@ public class TcpClient implements AutoCloseable {
         }
     }
 
-    public synchronized void flush() {
+    public synchronized void flush() throws IOException {
         if (null != out) {
             out.flush();
             writesSinceFlush = 0;
@@ -94,12 +94,12 @@ public class TcpClient implements AutoCloseable {
     }
 
     private synchronized int connect() {
-        if (null == sock || !sock.isConnected() || out.checkError()) {
+        if (null == sock || !sock.isConnected()) {
             if (System.currentTimeMillis() > (connectTime + backoff)) {
                 try {
                     connectTime = System.currentTimeMillis();
                     sock = new Socket(host, port);
-                    out = new PrintWriter(sock.getOutputStream(), false);
+                    out = new BufferedWriter(new OutputStreamWriter(sock.getOutputStream()));
                     backoff = 2000;
                     LOG.trace("Connected to Timely at {}:{}", host, port);
                 } catch (IOException e) {

client/src/main/java/timely/model/ObjectSizeOf.java

@@ -62,7 +62,6 @@ public interface ObjectSizeOf {
          * ObjectSizeOf interface and if implemented on the object will use that.
          * Otherwise it will do a simple navigation of the fields using reflection.
          *
-         * @param o
          * @return an approximation of the object size
          */
         public static long getObjectSize(Object o, boolean useSizeInBytesMethod, boolean debug) {

client/src/main/java/timely/model/Tag.java

@@ -77,8 +77,6 @@ public class Tag implements Comparable<Tag>, Serializable {
 
     /**
      * Joins key and value into key=value
-     * 
-     * @return
      */
     public String join() {
         return tagParser.combine(this);

client/src/main/java/timely/model/parse/TagListParser.java

@@ -47,7 +47,6 @@ public class TagListParser implements Parser<List<Tag>>, Combiner<Collection<Tag
      * An alternative combiner for a map of string to string instead of a list of
      * tags
      * 
-     * @param tags
      * @return string representation
      */
     public String combine(Map<String, String> tags) {

client/src/main/spotbugs/excludes.xml

@@ -5,4 +5,9 @@
     <Method name="connect" />
     <Class name="timely.client.tcp.TcpClient"/>
   </Match>
+  <Match>
+    <!-- Must ignore these everywhere, because of a javac byte code generation bug -->
+    <!-- https://github.com/spotbugs/spotbugs/issues/756 -->
+    <Bug pattern="RCN_REDUNDANT_NULLCHECK_WOULD_HAVE_BEEN_A_NPE" />
+  </Match>
 </FindBugsFilter>

client/src/test/java/timely/api/SerializationTest.java

@@ -47,9 +47,9 @@ public class SerializationTest {
         testSerialization(remove);
     }
 
-    @SuppressWarnings("unchecked")
     private <T> void testSerialization(T o) throws Exception {
         String ser = mapper.writeValueAsString(o);
+        @SuppressWarnings("unchecked")
         T des = mapper.readValue(ser, (Class<T>) o.getClass());
         Assert.assertEquals(o, des);
     }

collectd-nsq-plugin/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>collectd-nsq-plugin</artifactId>
   <dependencies>

collectd-nsq-plugin/src/main/java/timely/collectd/plugin/PooledCloseableHttpClientFactory.java

@@ -10,7 +10,7 @@ import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.collectd.api.OConfigItem;
 
-public class PooledCloseableHttpClientFactory implements PooledObjectFactory {
+public class PooledCloseableHttpClientFactory implements PooledObjectFactory<CloseableHttpClient> {
 
     private int connectionRequestTimeout = 10000; // 10 seconds in milliseconds
     private int connectTimeout = 30000; // 30 seconds in milliseconds
@@ -43,19 +43,19 @@ public class PooledCloseableHttpClientFactory implements PooledObjectFactory {
     }
 
     @Override
-    public PooledObject makeObject() throws Exception {
+    public PooledObject<CloseableHttpClient> makeObject() throws Exception {
         RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(connectionRequestTimeout)
                 .setConnectTimeout(connectTimeout).setSocketTimeout(socketTimeout).build();
         HttpClientBuilder builder = HttpClientBuilder.create();
         builder.setDefaultRequestConfig(requestConfig);
         builder.setConnectionTimeToLive(connectionTimeToLive, TimeUnit.MILLISECONDS);
-        return new DefaultPooledObject(builder.build());
+        return new DefaultPooledObject<>(builder.build());
     }
 
     @Override
-    public void destroyObject(PooledObject pooledObject) throws Exception {
+    public void destroyObject(PooledObject<CloseableHttpClient> pooledObject) throws Exception {
         try {
-            ((CloseableHttpClient) pooledObject.getObject()).close();
+            pooledObject.getObject().close();
         } catch (Exception e) {
             // do nothing
         } finally {
@@ -65,17 +65,17 @@ public class PooledCloseableHttpClientFactory implements PooledObjectFactory {
     }
 
     @Override
-    public boolean validateObject(PooledObject pooledObject) {
+    public boolean validateObject(PooledObject<CloseableHttpClient> pooledObject) {
         return pooledObject.getObject() != null;
     }
 
     @Override
-    public void activateObject(PooledObject pooledObject) throws Exception {
+    public void activateObject(PooledObject<CloseableHttpClient> pooledObject) throws Exception {
         // do nothing
     }
 
     @Override
-    public void passivateObject(PooledObject pooledObject) throws Exception {
+    public void passivateObject(PooledObject<CloseableHttpClient> pooledObject) throws Exception {
         // do nothing
     }
 

collectd-nsq-plugin/src/main/java/timely/collectd/plugin/WriteNSQPlugin.java

@@ -47,6 +47,7 @@ public class WriteNSQPlugin extends CollectDPluginParent
         Collectd.registerWrite(WriteNSQPlugin.class.getName(), this);
     }
 
+    @Override
     public int write(ValueList vl) {
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         DataOutputStream out = new DataOutputStream(baos);
@@ -110,15 +111,17 @@ public class WriteNSQPlugin extends CollectDPluginParent
         }
     }
 
+    @Override
     public int shutdown() {
         Collectd.logInfo("Shutting down connection to NSQ at " + host + ":" + port);
         clientPool.close();
         return 0;
     }
 
+    @Override
     public int config(OConfigItem config) {
         super.config(config);
-        GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
+        GenericObjectPoolConfig<CloseableHttpClient> poolConfig = new GenericObjectPoolConfig<>();
         // use max size for maxTotal and maxIdle
         // no need to activate or passivate
         poolConfig.setMaxTotal(POOL_MAX_SIZE);
@@ -156,7 +159,7 @@ public class WriteNSQPlugin extends CollectDPluginParent
             Collectd.logError("NSQ host, port, and topic must be configured");
             return -1;
         }
-        this.clientPool = new GenericObjectPool(pooledCloseableHttpClientFactory, poolConfig);
+        this.clientPool = new GenericObjectPool<>(pooledCloseableHttpClientFactory, poolConfig);
         this.endpoint = "http://" + host + ":" + port + "/mpub?topic=" + topic;
         return 0;
     }

collectd-plugin-parent/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>collectd-plugin-parent</artifactId>
   <dependencies>

collectd-timely-plugin/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>collectd-timely-plugin</artifactId>
   <dependencies>

collectd-timely-plugin/src/main/java/timely/collectd/plugin/PooledSocketFactory.java

@@ -8,7 +8,7 @@ import org.apache.commons.pool2.impl.DefaultPooledObject;
 import org.collectd.api.Collectd;
 import org.collectd.api.OConfigItem;
 
-public class PooledSocketFactory implements PooledObjectFactory {
+public class PooledSocketFactory implements PooledObjectFactory<Socket> {
 
     private String host = null;
     private int port = 0;
@@ -81,12 +81,12 @@ public class PooledSocketFactory implements PooledObjectFactory {
     }
 
     @Override
-    public PooledObject makeObject() throws Exception {
-        return new DefaultPooledObject(connect());
+    public PooledObject<Socket> makeObject() throws Exception {
+        return new DefaultPooledObject<>(connect());
     }
 
     @Override
-    public void destroyObject(PooledObject pooledObject) throws Exception {
+    public void destroyObject(PooledObject<Socket> pooledObject) throws Exception {
         try {
             Collectd.logDebug("Shutting down connection to Timely at " + host + ":" + port);
             Socket socket = (Socket) pooledObject.getObject();
@@ -103,7 +103,7 @@ public class PooledSocketFactory implements PooledObjectFactory {
     }
 
     @Override
-    public boolean validateObject(PooledObject pooledObject) {
+    public boolean validateObject(PooledObject<Socket> pooledObject) {
         if (connectionTimeToLive > -1) {
             if (System.currentTimeMillis() > pooledObject.getCreateTime() + connectionTimeToLive) {
                 return false;
@@ -114,12 +114,12 @@ public class PooledSocketFactory implements PooledObjectFactory {
     }
 
     @Override
-    public void activateObject(PooledObject pooledObject) throws Exception {
+    public void activateObject(PooledObject<Socket> pooledObject) throws Exception {
         // do nothing
     }
 
     @Override
-    public void passivateObject(PooledObject pooledObject) throws Exception {
+    public void passivateObject(PooledObject<Socket> pooledObject) throws Exception {
         // do nothing
     }
 }

collectd-timely-plugin/src/main/java/timely/collectd/plugin/WriteTimelyPlugin.java

@@ -86,13 +86,13 @@ public class WriteTimelyPlugin extends CollectDPluginParent
         PooledSocketFactory socketFactory = new PooledSocketFactory();
         retval = socketFactory.config(config);
         if (retval == 0) {
-            GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();
+            GenericObjectPoolConfig<Socket> poolConfig = new GenericObjectPoolConfig<>();
             // use max size for maxTotal and maxIdle
             // no need to activate and passivate
             poolConfig.setMaxTotal(POOL_MAX_SIZE);
             poolConfig.setMaxIdle(POOL_MAX_SIZE);
             poolConfig.setTestOnReturn(true);
-            socketPool = new GenericObjectPool(socketFactory, poolConfig);
+            socketPool = new GenericObjectPool<>(socketFactory, poolConfig);
         }
         return retval;
     }

common/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>timely-common</artifactId>
   <dependencies>

grafana-auth/bin/grafana-auth.sh

@@ -32,7 +32,7 @@ $JAVA_HOME/bin/jar xf ${LIB_DIR}/netty-all*.jar META-INF/native/libnetty_transpo
 popd
 
 export CLASSPATH="${CONF_DIR}:${LIB_DIR}/*:${HADOOP_CONF_DIR}"
-JVM_ARGS="-Xmx1G -Xms1G -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS}"
+JVM_ARGS="-Xmx1G -Xms1G -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS} Dlog4j.configurationFile=${CONF_DIR}/log4j2-spring.xml"
 JVM_ARGS="${JVM_ARGS} -DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector"
 JVM_ARGS="${JVM_ARGS} -Djava.library.path=${NATIVE_DIR}"
 

grafana-auth/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>grafana-auth</artifactId>
   <dependencies>
@@ -166,7 +166,6 @@
     <dependency>
       <groupId>io.netty</groupId>
       <artifactId>netty-tcnative-boringssl-static</artifactId>
-      <version>${version.netty-tcnative}</version>
       <scope>runtime</scope>
     </dependency>
     <dependency>

grafana-auth/src/main/java/timely/grafana/auth/GrafanaAuth.java

@@ -81,8 +81,11 @@ public class GrafanaAuth {
         this.grafanaAuthConfig = grafanaAuthConfig;
     }
 
-    protected static ConfigurableApplicationContext initializeConfiguration(String[] args) {
-        return new SpringApplicationBuilder(SpringBootstrap.class).web(WebApplicationType.NONE).run(args);
+    protected static ConfigurableApplicationContext initializeContext(String[] args) {
+        SpringApplicationBuilder builder = new SpringApplicationBuilder(SpringBootstrap.class);
+        builder.web(WebApplicationType.NONE);
+        builder.registerShutdownHook(false);
+        return builder.run(args);
     }
 
     private void shutdownHook() {
@@ -109,13 +112,11 @@ public class GrafanaAuth {
             try {
                 f.get();
             } catch (final Exception e) {
-                LOG.error("Error while shutting down channel: {}", f.channel().config());
-                LOG.error("{}", e.getMessage());
-                e.printStackTrace();
+                LOG.error("Channel:" + f.channel().config() + " -> " + e.getMessage(), e);
             }
         });
 
-        Integer quietPeriod = grafanaAuthConfig.getShutdownQuietPeriod();
+        int quietPeriod = grafanaAuthConfig.getShutdownQuietPeriod();
         List<Future<?>> groupFutures = new ArrayList<>();
 
         if (httpBossGroup != null) {
@@ -132,9 +133,7 @@ public class GrafanaAuth {
             try {
                 f.get();
             } catch (final Exception e) {
-                LOG.error("Error while shutting down group: {}", f.toString());
-                LOG.error("{}", e.getMessage());
-                e.printStackTrace();
+                LOG.error("Group:" + f.toString() + " -> " + e.getMessage(), e);
             }
         });
 
@@ -272,12 +271,13 @@ public class GrafanaAuth {
 
     public static void main(String[] args) throws Exception {
 
-        GrafanaAuth.applicationContext = GrafanaAuth.initializeConfiguration(args);
-        GrafanaAuthConfiguration balancerConf = applicationContext.getBean(GrafanaAuthConfiguration.class);
+        GrafanaAuth.applicationContext = GrafanaAuth.initializeContext(args);
+        GrafanaAuthConfiguration grafanaAuthConf = GrafanaAuth.applicationContext
+                .getBean(GrafanaAuthConfiguration.class);
 
-        GrafanaAuth b = new GrafanaAuth(balancerConf);
+        GrafanaAuth grafanaAuth = new GrafanaAuth(grafanaAuthConf);
         try {
-            b.run();
+            grafanaAuth.run();
             LATCH.await();
         } catch (final InterruptedException e) {
             LOG.info("Server shutting down.");
@@ -285,7 +285,7 @@ public class GrafanaAuth {
             LOG.error("Error running server.", e);
         } finally {
             try {
-                b.shutdown();
+                grafanaAuth.shutdown();
             } catch (Exception e) {
                 System.exit(1);
             }
@@ -314,7 +314,8 @@ public class GrafanaAuth {
                 ch.pipeline().addLast("fileServer", new HttpStaticFileServerHandler());
                 ch.pipeline().addLast("login", new X509LoginRequestHandler(config.getSecurity(), config.getHttp()));
                 ch.pipeline().addLast("httpRelay", new GrafanaRelayHandler(config, httpClientPool));
-                ch.pipeline().addLast("error", new TimelyExceptionHandler());
+                ch.pipeline().addLast("error", new TimelyExceptionHandler()
+                        .setIgnoreSslHandshakeErrors(config.getSecurity().getServerSsl().isUseGeneratedKeypair()));
             }
         };
     }

grafana-auth/src/main/java/timely/grafana/auth/configuration/GrafanaAuthConfiguration.java

@@ -43,8 +43,6 @@ public class GrafanaAuthConfiguration {
     /**
      * Time to wait (in seconds) for connections to finish and to make sure no new
      * connections happen before shutting down Netty event loop groups.
-     *
-     * @return
      */
     public int getShutdownQuietPeriod() {
         return this.shutdownQuietPeriod;

grafana-auth/src/main/java/timely/grafana/auth/netty/http/GrafanaRelayHandler.java

@@ -1,6 +1,6 @@
 package timely.grafana.auth.netty.http;
 
-import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_LENGTH;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
 
 import java.io.ByteArrayOutputStream;
 import java.net.URLEncoder;
@@ -71,7 +71,7 @@ public class GrafanaRelayHandler extends SimpleChannelInboundHandler<HttpRequest
         try {
             try {
                 request = msg.getHttpRequest();
-                String originalURI = request.getUri();
+                String originalURI = request.uri();
                 originalURI = encodeURI(originalURI);
 
                 if (msg instanceof GrafanaRequest) {
@@ -87,42 +87,42 @@ public class GrafanaRelayHandler extends SimpleChannelInboundHandler<HttpRequest
                 String protocol = config.getGrafana().getProtocol();
                 String host = config.getGrafana().getHost();
                 Integer port = config.getGrafana().getPort();
-                k = TimelyBalancedHost.of(host, -1, port, -1, -1);
+                k = TimelyBalancedHost.of(host, -1, port, -1, -1, null);
                 client = httpClientPool.borrowObject(k);
                 Multimap<String, String> headers = HttpHeaderUtils.toMultimap(request.headers());
 
                 // If incoming user sets these headers, do not relay them
-                headers.removeAll("X-WEBAUTH-USER");
-                headers.removeAll("X-WEBAUTH-NAME");
+                headers.removeAll("x-webauth-user");
+                headers.removeAll("x-webauth-name");
                 TimelyPrincipal principal = token.getTimelyPrincipal();
                 TimelyUser user = principal.getPrimaryUser();
                 String subjectDn = user.getDn().subjectDN();
                 String userName = DnUtils.getCommonName(subjectDn);
                 String loginName = DnUtils.getShortName(subjectDn);
-                headers.put("X-WEBAUTH-USER", loginName);
-                headers.put("X-WEBAUTH-NAME", userName);
+                headers.put("x-webauth-user", loginName);
+                headers.put("x-webauth-name", userName);
                 List<Header> relayedHeaderList = new ArrayList<>();
                 for (Map.Entry<String, String> h : headers.entries()) {
-                    if (!h.getKey().equals(CONTENT_LENGTH)) {
+                    if (!h.getKey().equals(CONTENT_LENGTH.toString())) {
                         relayedHeaderList.add(new BasicHeader(h.getKey(), h.getValue()));
                     }
                 }
                 Header[] headerArray = new Header[relayedHeaderList.size()];
                 relayedHeaderList.toArray(headerArray);
                 relayURI = protocol + "://" + host + ":" + port + originalURI;
-                if (request.getMethod().equals(HttpMethod.HEAD)) {
+                if (request.method().equals(HttpMethod.HEAD)) {
                     HttpHead relayedRequest = new HttpHead(relayURI);
                     if (headerArray.length > 0) {
                         relayedRequest.setHeaders(headerArray);
                     }
                     relayedResponse = client.execute(relayedRequest);
-                } else if (request.getMethod().equals(HttpMethod.GET)) {
+                } else if (request.method().equals(HttpMethod.GET)) {
                     HttpGet relayedRequest = new HttpGet(relayURI);
                     if (headerArray.length > 0) {
                         relayedRequest.setHeaders(headerArray);
                     }
                     relayedResponse = client.execute(relayedRequest);
-                } else if (request.getMethod().equals(HttpMethod.POST)) {
+                } else if (request.method().equals(HttpMethod.POST)) {
                     HttpPost relayedRequest = new HttpPost(relayURI);
                     String content = request.content().toString(StandardCharsets.UTF_8);
                     StringEntity entity = new StringEntity(content);
@@ -131,7 +131,7 @@ public class GrafanaRelayHandler extends SimpleChannelInboundHandler<HttpRequest
                         relayedRequest.setHeaders(headerArray);
                     }
                     relayedResponse = client.execute(relayedRequest);
-                } else if (request.getMethod().equals(HttpMethod.PUT)) {
+                } else if (request.method().equals(HttpMethod.PUT)) {
                     HttpPut relayedRequest = new HttpPut(relayURI);
                     String content = request.content().toString(StandardCharsets.UTF_8);
                     StringEntity entity = new StringEntity(content);
@@ -140,13 +140,13 @@ public class GrafanaRelayHandler extends SimpleChannelInboundHandler<HttpRequest
                         relayedRequest.setHeaders(headerArray);
                     }
                     relayedResponse = client.execute(relayedRequest);
-                } else if (request.getMethod().equals(HttpMethod.DELETE)) {
+                } else if (request.method().equals(HttpMethod.DELETE)) {
                     HttpDelete relayedRequest = new HttpDelete(relayURI);
                     if (headerArray.length > 0) {
                         relayedRequest.setHeaders(headerArray);
                     }
                     relayedResponse = client.execute(relayedRequest);
-                } else if (request.getMethod().equals(HttpMethod.OPTIONS)) {
+                } else if (request.method().equals(HttpMethod.OPTIONS)) {
                     HttpOptions relayedRequest = new HttpOptions(relayURI);
                     if (headerArray.length > 0) {
                         relayedRequest.setHeaders(headerArray);
@@ -199,7 +199,7 @@ public class GrafanaRelayHandler extends SimpleChannelInboundHandler<HttpRequest
             if (client != null && k != null) {
                 httpClientPool.returnObject(k, client);
             } else {
-                LOG.error("NOT RETURNING CONNECTION! " + msg.getHttpRequest().getUri());
+                LOG.error("NOT RETURNING CONNECTION! " + msg.getHttpRequest().uri());
             }
         }
     }

grafana-auth/src/main/java/timely/grafana/auth/netty/http/GrafanaRequestDecoder.java

@@ -8,7 +8,7 @@ import com.google.common.collect.Multimap;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToMessageDecoder;
 import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.QueryStringDecoder;
 import io.netty.handler.codec.http.cookie.ServerCookieDecoder;
 import org.apache.commons.lang3.StringUtils;
@@ -47,7 +47,7 @@ public class GrafanaRequestDecoder extends MessageToMessageDecoder<FullHttpReque
 
     public static String getSessionId(FullHttpRequest msg) {
         Multimap<String, String> headers = HttpHeaderUtils.toMultimap(msg.headers());
-        Collection<String> cookies = headers.get(Names.COOKIE);
+        Collection<String> cookies = headers.get(HttpHeaderNames.COOKIE.toString());
         final StringBuilder buf = new StringBuilder();
         cookies.forEach(h -> {
             ServerCookieDecoder.STRICT.decode(h).forEach(c -> {
@@ -70,7 +70,7 @@ public class GrafanaRequestDecoder extends MessageToMessageDecoder<FullHttpReque
 
         LOG.trace(LOG_RECEIVED_REQUEST, msg);
 
-        final String uri = msg.getUri();
+        final String uri = msg.uri();
         final QueryStringDecoder decoder = new QueryStringDecoder(uri);
         if (decoder.path().equals(nonSecureRedirectAddress)) {
             out.add(new StrictTransportResponse());

grafana/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>timely-app</artifactId>
   <packaging>pom</packaging>

grafana/timely-app/dist/datasource/datasource.js

@@ -509,7 +509,7 @@ System.register(['lodash', 'angular', '../../../app/core/utils/datemath'], funct
                 } else {
                   return target.metric === metricData.metric && _.every(target.tags, function (tagV, tagK) {
                     interpolatedTagValue = this.templateSrv.replace(tagV, options.scopedVars, 'pipe');
-                    return metricData.tags[tagK] === interpolatedTagValue || interpolatedTagValue === "*";
+                    return metricData.tags[tagK] === interpolatedTagValue || interpolatedTagValue === ".*";
                   }.bind(this));
                 }
               }.bind(this));

grafana/timely-app/dist/datasource/datasource.js.map

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grafana/timely-app/dist/plugin.json

@@ -23,8 +23,8 @@
       {"name": "Project site", "url": "https://github.com/NationalSecurityAgency/timely"},
       {"name": "License & Terms", "url": "https://raw.githubusercontent.com/NationalSecurityAgency/timely/master/LICENSE"}
     ],
-    "version": "1.2.3",
-    "updated": "2019-04-18"
+    "version": "1.2.8-SNAPSHOT",
+    "updated": "2020-02-21"
   },
 
   "includes": [

grafana/timely-app/package.json

@@ -1,7 +1,7 @@
 {
   "name": "timely-app",
   "private": true,
-  "version": "1.2.3",
+  "version": "1.2.8-SNAPSHOT",
   "description": "",
   "main": "index.js",
   "scripts": {

grafana/timely-app/plugin.json

@@ -23,8 +23,8 @@
       {"name": "Project site", "url": "https://github.com/NationalSecurityAgency/timely"},
       {"name": "License & Terms", "url": "https://raw.githubusercontent.com/NationalSecurityAgency/timely/master/LICENSE"}
     ],
-    "version": "1.2.3",
-    "updated": "2019-04-18"
+    "version": "1.2.8-SNAPSHOT",
+    "updated": "2020-02-21"
   },
 
   "includes": [

grafana/timely-app/src/datasource/datasource.js

@@ -446,7 +446,7 @@ export class TimelyDatasource {
         } else {
           return target.metric === metricData.metric && _.every(target.tags, function(tagV, tagK) {
                 interpolatedTagValue = this.templateSrv.replace(tagV, options.scopedVars, 'pipe');
-                return metricData.tags[tagK] === interpolatedTagValue || interpolatedTagValue === "*";
+                return metricData.tags[tagK] === interpolatedTagValue || interpolatedTagValue === ".*";
               }.bind(this));
         }
       }.bind(this));

pom.xml

@@ -3,7 +3,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>timely</groupId>
   <artifactId>timely</artifactId>
-  <version>1.2.3</version>
+  <version>1.2.8-SNAPSHOT</version>
   <packaging>pom</packaging>
   <name>Timely</name>
   <description>A secure and scalable time series database based on Apache Accumulo</description>
@@ -41,7 +41,7 @@
     <os.detection.classifierWithLikes>fedora</os.detection.classifierWithLikes>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-    <version.accumulo>1.9.2</version.accumulo>
+    <version.accumulo>1.9.3</version.accumulo>
     <version.buildnumber-maven>1.4</version.buildnumber-maven>
     <version.caffeine>2.6.2</version.caffeine>
     <version.collectd>5.7.1</version.collectd>
@@ -50,37 +50,39 @@
     <version.commons-pool2>2.6.1</version.commons-pool2>
     <version.curator>4.1.0</version.curator>
     <version.disruptor>3.4.2</version.disruptor>
+    <version.easymock>4.0.2</version.easymock>
     <version.eclipse-lifecycle>1.0.0</version.eclipse-lifecycle>
     <version.fast-classpath-scanner>3.1.13</version.fast-classpath-scanner>
     <version.flink>1.1.4</version.flink>
     <version.google-flatbuffers>1.10.0</version.google-flatbuffers>
     <version.guava>27.1-jre</version.guava>
-    <version.hadoop>2.7.3</version.hadoop>
+    <version.hadoop>2.7.7</version.hadoop>
     <version.httpcomponents>4.5.6</version.httpcomponents>
-    <version.impsort>1.2.0</version.impsort>
-    <version.jackson>2.9.8</version.jackson>
-    <version.jacoco>0.7.6.201602180812</version.jacoco>
+    <version.impsort>1.3.0</version.impsort>
+    <version.jackson>2.10.0</version.jackson>
+    <version.jackson.databind>2.10.0</version.jackson.databind>
+    <version.jacoco>0.8.4</version.jacoco>
     <version.javacsv>2.0</version.javacsv>
     <version.javassist>3.24.1-GA</version.javassist>
     <version.jcip-annotations>1.0</version.jcip-annotations>
     <version.jsoup>1.11.3</version.jsoup>
     <version.junit>4.12</version.junit>
     <version.log4j>2.11.2</version.log4j>
-    <version.maven-assembly>2.6</version.maven-assembly>
-    <version.maven-build-helper>1.12</version.maven-build-helper>
-    <version.maven-compiler>3.3</version.maven-compiler>
-    <version.maven-dependency>2.10</version.maven-dependency>
-    <version.maven-jar>3.0.1</version.maven-jar>
-    <version.maven-pmd>3.6</version.maven-pmd>
-    <version.maven-rpm>2.1.4</version.maven-rpm>
-    <version.maven-shade>2.4.2</version.maven-shade>
-    <version.maven-surefire>2.19.1</version.maven-surefire>
-    <version.netty>4.1.35.Final</version.netty>
+    <version.maven-assembly>3.1.1</version.maven-assembly>
+    <version.maven-build-helper>3.0.0</version.maven-build-helper>
+    <version.maven-compiler>3.8.1</version.maven-compiler>
+    <version.maven-dependency>3.1.1</version.maven-dependency>
+    <version.maven-jar>3.1.2</version.maven-jar>
+    <version.maven-pmd>3.12.0</version.maven-pmd>
+    <version.maven-rpm>2.2.0</version.maven-rpm>
+    <version.maven-shade>3.2.1</version.maven-shade>
+    <version.maven-surefire>3.0.0-M3</version.maven-surefire>
+    <version.netty>4.1.42.Final</version.netty>
     <version.netty-tcnative>2.0.25.Final</version.netty-tcnative>
     <version.os-maven>1.5.0.Final</version.os-maven>
     <version.powermock>1.6.4</version.powermock>
     <version.slf4j>1.7.26</version.slf4j>
-    <version.spotbugs-maven>3.1.7</version.spotbugs-maven>
+    <version.spotbugs-maven>3.1.12.1</version.spotbugs-maven>
     <version.spring-boot>2.1.3.RELEASE</version.spring-boot>
     <version.tyrus>1.15</version.tyrus>
   </properties>
@@ -99,7 +101,7 @@
       <dependency>
         <groupId>com.fasterxml.jackson.core</groupId>
         <artifactId>jackson-databind</artifactId>
-        <version>${version.jackson}</version>
+        <version>${version.jackson.databind}</version>
       </dependency>
       <dependency>
         <groupId>com.fasterxml.jackson.datatype</groupId>
@@ -146,6 +148,11 @@
         <artifactId>netty-all</artifactId>
         <version>${version.netty}</version>
       </dependency>
+      <dependency>
+        <groupId>io.netty</groupId>
+        <artifactId>netty-tcnative-boringssl-static</artifactId>
+        <version>${version.netty-tcnative}</version>
+      </dependency>
       <dependency>
         <groupId>net.sourceforge.javacsv</groupId>
         <artifactId>javacsv</artifactId>
@@ -391,6 +398,12 @@
         <version>${version.jcip-annotations}</version>
         <scope>test</scope>
       </dependency>
+      <dependency>
+        <groupId>org.easymock</groupId>
+        <artifactId>easymock</artifactId>
+        <version>${version.easymock}</version>
+        <scope>test</scope>
+      </dependency>
       <dependency>
         <groupId>org.powermock</groupId>
         <artifactId>powermock-easymock-release-full</artifactId>
@@ -406,7 +419,7 @@
         <plugin>
           <groupId>net.revelc.code.formatter</groupId>
           <artifactId>formatter-maven-plugin</artifactId>
-          <version>2.8.0</version>
+          <version>2.10.0</version>
           <configuration>
             <compilerCompliance>${maven.compiler.source}</compilerCompliance>
             <compilerSource>${maven.compiler.source}</compilerSource>
@@ -424,7 +437,7 @@
         <plugin>
           <groupId>com.github.ekryd.sortpom</groupId>
           <artifactId>sortpom-maven-plugin</artifactId>
-          <version>2.8.0</version>
+          <version>2.10.0</version>
           <configuration>
             <predefinedSortOrder>recommended_2008_06</predefinedSortOrder>
             <createBackupFile>false</createBackupFile>
@@ -456,7 +469,7 @@
           <artifactId>maven-failsafe-plugin</artifactId>
           <version>${version.maven-surefire}</version>
           <configuration>
-            <argLine>${failsafeArgLine} -Djava.library.path=${project.build.directory}/native/META-INF/native/libnetty-tcnative_linux_x86_64.so -Dzookeeper.sasl.client=false</argLine>
+            <argLine>${failsafeArgLine} -Djava.library.path=${project.build.directory}/native/META-INF/native/libnetty_tcnative_linux_x86_64.so -Dzookeeper.sasl.client=false</argLine>
             <includes>
               <include>**/*.java</include>
             </includes>
@@ -568,7 +581,7 @@
             <configuration>
               <rules>
                 <requireMavenVersion>
-                  <version>3.0.5</version>
+                  <version>3.5.0</version>
                 </requireMavenVersion>
                 <requireJavaVersion>
                   <version>[${maven.compiler.target},)</version>
@@ -739,6 +752,9 @@
           <name>m2e.version</name>
         </property>
       </activation>
+      <properties>
+        <maven.compiler.release>8</maven.compiler.release>
+      </properties>
       <build>
         <pluginManagement>
           <plugins>
@@ -799,5 +815,14 @@
         </pluginManagement>
       </build>
     </profile>
+    <profile>
+      <id>jdk-release-flag</id>
+      <activation>
+        <jdk>[9,)</jdk>
+      </activation>
+      <properties>
+        <maven.compiler.release>8</maven.compiler.release>
+      </properties>
+    </profile>
   </profiles>
 </project>

server/bin/get-tablet-summary.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+if [[ `uname` == "Darwin" ]]; then
+        THIS_SCRIPT=`python -c 'import os,sys; print os.path.realpath(sys.argv[1])' $0`
+else
+        THIS_SCRIPT=`readlink -f $0`
+fi
+
+THIS_DIR="${THIS_SCRIPT%/*}"
+BASE_DIR=${THIS_DIR}/..
+CONF_DIR="${BASE_DIR}/conf"
+LIB_DIR="${BASE_DIR}/lib"
+
+export CLASSPATH="${CONF_DIR}:${LIB_DIR}/*"
+JVM_ARGS="-Xmx1024m -Xms128m"
+JVM_ARGS="${JVM_ARGS} -Dlogging.config=${CONF_DIR}/log4j2-error-console.xml"
+JVM_ARGS="${JVM_ARGS} -Dlog4j.configurationFile=${CONF_DIR}/log4j2-error-console.xml"
+JVM_ARGS="${JVM_ARGS} -DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector"
+
+echo "$JAVA_HOME/bin/java ${JVM_ARGS} timely.store.compaction.util.TabletMetadataConsole --spring.config.name=timely"
+$JAVA_HOME/bin/java ${JVM_ARGS} timely.store.compaction.util.TabletMetadataConsole --spring.config.name=timely

server/bin/timely-server.sh

@@ -32,7 +32,7 @@ $JAVA_HOME/bin/jar xf ${LIB_DIR}/netty-all*.jar META-INF/native/libnetty_transpo
 popd
 
 export CLASSPATH="${CONF_DIR}:${LIB_DIR}/*:${HADOOP_CONF_DIR}"
-JVM_ARGS="-Xmx256m -Xms256m -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS}" -Dlog4j.configurationFile=${CONF_DIR}/log4j2-spring.xml
+JVM_ARGS="-Xmx256m -Xms256m -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS} -Dlog4j.configurationFile=${CONF_DIR}/log4j2-spring.xml"
 JVM_ARGS="${JVM_ARGS} -DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector"
 JVM_ARGS="${JVM_ARGS} -Djava.library.path=${NATIVE_DIR}"
 

server/bin/timely-standalone.sh

@@ -32,7 +32,7 @@ $JAVA_HOME/bin/jar xf ${LIB_DIR}/netty-all*.jar META-INF/native/libnetty_transpo
 popd
 
 export CLASSPATH="${CONF_DIR}:${LIB_DIR}/*:${HADOOP_CONF_DIR}"
-JVM_ARGS="-Xmx256m -Xms256m -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS}" -Dlog4j.configurationFile=${CONF_DIR}/log4j2-spring.xml
+JVM_ARGS="-Xmx256m -Xms256m -Dio.netty.eventLoopThreads=${NUM_SERVER_THREADS} -Dlog4j.configurationFile=${CONF_DIR}/log4j2-spring.xml"
 JVM_ARGS="${JVM_ARGS} -DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector"
 JVM_ARGS="${JVM_ARGS} -Djava.library.path=${NATIVE_DIR}"
 # for debugging

server/conf/timely-docker.yml

@@ -22,7 +22,7 @@ timely:
     cache-refresh-minutes: 5
     allow-anonymous-http-access: true
     allow-anonymous-ws-access: true
-    ssl:
+    server-ssl:
       certificate-file: /timely-server-src/server/pki/timely.csr
       key-file: /timely-server-src/server/pki/timely-pkcs8.key
       key-password: password

server/conf/timely-standalone.yml

@@ -3,6 +3,8 @@ timely:
   meta-table: timely.meta
   metric-age-off-days:
     default: 7
+  cache:
+    enabled: false
   metrics-report-ignored-tags:
   accumulo:
     instance-name: TimelyStandalone
@@ -22,7 +24,7 @@ timely:
     cache-refresh-minutes: 5
     allow-anonymous-http-access: true
     allow-anonymous-ws-access: true
-    ssl:
+    server-ssl:
       certificate-file:
       key-file:
       key-password: timely

server/conf/timely.yml

@@ -27,7 +27,7 @@ timely:
     cache-refresh-minutes: 5
     allow-anonymous-http-access: true
     allow-anonymous-ws-access: true
-    serverSsl:
+    server-ssl:
       certificate-file:
       key-file:
       key-password:

server/pom.xml

@@ -4,7 +4,7 @@
   <parent>
     <groupId>timely</groupId>
     <artifactId>timely</artifactId>
-    <version>1.2.3</version>
+    <version>1.2.8-SNAPSHOT</version>
   </parent>
   <artifactId>timely-server</artifactId>
   <dependencies>
@@ -108,6 +108,10 @@
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-minicluster</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.glassfish.tyrus</groupId>
+      <artifactId>tyrus-client</artifactId>
+    </dependency>
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
@@ -150,7 +154,6 @@
     <dependency>
       <groupId>io.netty</groupId>
       <artifactId>netty-tcnative-boringssl-static</artifactId>
-      <version>${version.netty-tcnative}</version>
       <scope>runtime</scope>
     </dependency>
     <dependency>
@@ -178,11 +181,22 @@
       <artifactId>junit</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.easymock</groupId>
+      <artifactId>easymock</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.jsoup</groupId>
       <artifactId>jsoup</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.powermock</groupId>
+      <artifactId>powermock-easymock-release-full</artifactId>
+      <classifier>full</classifier>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-test-autoconfigure</artifactId>

server/src/main/java/timely/Server.java

@@ -24,6 +24,7 @@ import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.WriteBufferWaterMark;
 import io.netty.channel.epoll.EpollChannelOption;
 import io.netty.channel.epoll.EpollDatagramChannel;
 import io.netty.channel.epoll.EpollEventLoopGroup;
@@ -44,6 +45,7 @@ import io.netty.handler.codec.http.HttpRequestDecoder;
 import io.netty.handler.codec.http.HttpResponseEncoder;
 import io.netty.handler.codec.http.HttpServerCodec;
 import io.netty.handler.codec.http.cors.CorsConfig;
+import io.netty.handler.codec.http.cors.CorsConfigBuilder;
 import io.netty.handler.codec.http.cors.CorsHandler;
 import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
 import io.netty.handler.logging.LoggingHandler;
@@ -58,6 +60,7 @@ import io.netty.handler.stream.ChunkedWriteHandler;
 import io.netty.handler.timeout.IdleStateHandler;
 import io.netty.util.NettyRuntime;
 import io.netty.util.internal.SystemPropertyUtil;
+import org.apache.accumulo.core.conf.AccumuloConfiguration;
 import org.apache.curator.RetryPolicy;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.CuratorFrameworkFactory;
@@ -73,7 +76,6 @@ import org.slf4j.LoggerFactory;
 import org.springframework.boot.WebApplicationType;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.context.ConfigurableApplicationContext;
-import timely.api.response.TimelyException;
 import timely.auth.AuthCache;
 import timely.auth.VisibilityCache;
 import timely.configuration.Configuration;
@@ -209,13 +211,13 @@ public class Server {
             payload.setWsPort(config.getWebsocket().getPort());
             payload.setUdpPort(config.getServer().getUdpPort());
 
-            ServiceInstanceBuilder builder = ServiceInstance.builder();
+            ServiceInstanceBuilder<ServerDetails> builder = ServiceInstance.builder();
             String serviceName = host + ":" + config.getServer().getTcpPort();
-            ServiceInstance serviceInstance = builder.id(serviceName).name("timely-server")
+            ServiceInstance<ServerDetails> serviceInstance = builder.id(serviceName).name("timely-server")
                     .address(config.getServer().getIp()).port(config.getServer().getTcpPort()).payload(payload).build();
 
-            ServiceDiscovery discovery = ServiceDiscoveryBuilder.builder(ServerDetails.class).client(curatorFramework)
-                    .basePath(SERVICE_DISCOVERY_PATH).build();
+            ServiceDiscovery<ServerDetails> discovery = ServiceDiscoveryBuilder.builder(ServerDetails.class)
+                    .client(curatorFramework).basePath(SERVICE_DISCOVERY_PATH).build();
             discovery.start();
             discovery.registerService(serviceInstance);
 
@@ -231,11 +233,12 @@ public class Server {
 
     public static void main(String[] args) throws Exception {
 
-        Configuration conf = initializeConfiguration(args);
+        Server.applicationContext = initializeContext(args);
+        Configuration conf = Server.applicationContext.getBean(Configuration.class);
 
-        Server s = new Server(conf);
+        Server server = new Server(conf);
         try {
-            s.run();
+            server.run();
             LATCH.await();
         } catch (final InterruptedException e) {
             LOG.info("Server shutting down.");
@@ -243,16 +246,18 @@ public class Server {
             LOG.error("Error running server.", e);
         } finally {
             try {
-                s.shutdown();
+                server.shutdown();
             } catch (Exception e) {
                 System.exit(1);
             }
         }
     }
 
-    protected static Configuration initializeConfiguration(String[] args) {
-        applicationContext = new SpringApplicationBuilder(SpringBootstrap.class).web(WebApplicationType.NONE).run(args);
-        return applicationContext.getBean(Configuration.class);
+    protected static ConfigurableApplicationContext initializeContext(String[] args) {
+        SpringApplicationBuilder builder = new SpringApplicationBuilder(SpringBootstrap.class);
+        builder.web(WebApplicationType.NONE);
+        builder.registerShutdownHook(false);
+        return builder.run(args);
     }
 
     private void shutdownHook() {
@@ -267,6 +272,8 @@ public class Server {
     }
 
     public void shutdown() {
+        LOG.warn("Server shutdown 1");
+
         List<ChannelFuture> channelFutures = new ArrayList<>();
 
         if (tcpChannelHandle != null) {
@@ -284,8 +291,9 @@ public class Server {
             channelFutures.add(wsChannelHandle.close());
         }
 
+        int udpChannel = 1;
         for (Channel c : udpChannelHandleList) {
-            LOG.info("Closing udpChannelHandle");
+            LOG.info("Closing udpChannelHandle #" + udpChannel++);
             channelFutures.add(c.close());
         }
 
@@ -294,14 +302,15 @@ public class Server {
             try {
                 f.get();
             } catch (final Exception e) {
-                LOG.error("Error while shutting down channel: {}", f.channel().config());
-                LOG.error("{}", e.getMessage());
-                e.printStackTrace();
+                LOG.error("Channel:" + f.channel().config() + " -> " + e.getMessage(), e);
             }
         });
 
-        Integer quietPeriod = config.getServer().getShutdownQuietPeriod();
+        LOG.warn("Server shutdown 2");
+
+        int quietPeriod = config.getServer().getShutdownQuietPeriod();
         List<Future<?>> groupFutures = new ArrayList<>();
+
         if (tcpBossGroup != null) {
             LOG.info("Shutting down tcpBossGroup");
             groupFutures.add(tcpBossGroup.shutdownGracefully(quietPeriod, 10, TimeUnit.SECONDS));
@@ -337,6 +346,8 @@ public class Server {
             groupFutures.add(udpBossGroup.shutdownGracefully(quietPeriod, 10, TimeUnit.SECONDS));
         }
 
+        LOG.warn("Server shutdown 3");
+
         if (udpWorkerGroup != null) {
             LOG.info("Shutting down udpWorkerGroup");
             groupFutures.add(udpWorkerGroup.shutdownGracefully(quietPeriod, 10, TimeUnit.SECONDS));
@@ -346,41 +357,70 @@ public class Server {
             try {
                 f.get();
             } catch (final Exception e) {
-                LOG.error("Error while shutting down group: {}", f.toString());
-                LOG.error("{}", e.getMessage());
-                e.printStackTrace();
+                LOG.error("Group:" + f.toString() + " -> " + e.getMessage(), e);
             }
         });
 
-        try {
-            LOG.info("Flushing datastore.");
-            dataStore.flush();
-        } catch (TimelyException e) {
-            LOG.error("Error flushing to server during shutdown", e);
-        }
+        LOG.warn("Server shutdown 4");
 
         try {
-            LOG.info("Closing MetaCacheFactory");
+            LOG.info("Closing dataStore");
+            dataStore.close();
+        } catch (Exception e) {
+            LOG.error(e.getMessage(), e);
+        }
+
+        LOG.warn("Server shutdown 5");
+
+        if (dataStoreCache != null) {
+            try {
+                LOG.info("Closing dataStoreCache");
+                dataStoreCache.close();
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
+        }
+
+        LOG.warn("Server shutdown 6");
+
+        try {
+            LOG.info("Closing metaCacheFactory");
             MetaCacheFactory.close();
         } catch (Exception e) {
-            LOG.error("Error closing MetaCacheFactory during shutdown", e);
+            LOG.error(e.getMessage(), e);
         }
 
+        LOG.warn("Server shutdown 7");
+
         try {
-            LOG.info("Closing WebSocketRequestDecoder");
+            LOG.info("Closing webSocketRequestDecoder subscriptions");
             WebSocketRequestDecoder.close();
         } catch (Exception e) {
-            LOG.error("Error closing WebSocketRequestDecoder during shutdown", e);
+            LOG.error(e.getMessage(), e);
         }
 
+        LOG.warn("Server shutdown 8");
+
         if (curatorFramework != null) {
-            curatorFramework.close();
+            try {
+                LOG.info("Closing curatorFramework");
+                curatorFramework.close();
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
         }
 
+        LOG.warn("Server shutdown 9");
+
         if (applicationContext != null) {
-            LOG.info("Closing applicationContext");
-            applicationContext.close();
+            try {
+                LOG.info("Closing applicationContext");
+                applicationContext.close();
+            } catch (Exception e) {
+                LOG.error(e.getMessage(), e);
+            }
         }
+        LOG.warn("Server shutdown 10");
         this.shutdown = true;
         LOG.info("Server shut down.");
     }
@@ -415,7 +455,9 @@ public class Server {
     public void run() throws Exception {
 
         RetryPolicy retryPolicy = new RetryForever(1000);
-        curatorFramework = CuratorFrameworkFactory.newClient(config.getAccumulo().getZookeepers(), 30000, 10000,
+        int timeout = Long.valueOf(AccumuloConfiguration.getTimeInMillis(config.getAccumulo().getZookeeperTimeout()))
+                .intValue();
+        curatorFramework = CuratorFrameworkFactory.newClient(config.getAccumulo().getZookeepers(), timeout, 10000,
                 retryPolicy);
         curatorFramework.start();
         ensureZkPaths(curatorFramework, zkPaths);
@@ -508,10 +550,9 @@ public class Server {
         wsServer.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
         wsServer.option(ChannelOption.SO_BACKLOG, 128);
         wsServer.option(ChannelOption.SO_KEEPALIVE, true);
-        /* Not sure if next three lines are necessary */
+        /* Not sure if next two lines are necessary */
         wsServer.option(ChannelOption.SO_SNDBUF, 1048576);
-        wsServer.option(ChannelOption.WRITE_BUFFER_HIGH_WATER_MARK, 838860);
-        wsServer.option(ChannelOption.WRITE_BUFFER_LOW_WATER_MARK, 620145);
+        wsServer.option(ChannelOption.WRITE_BUFFER_WATER_MARK, new WriteBufferWaterMark(620145, 838860));
         wsChannelHandle = wsServer.bind(wsIp, wsPort).sync().channel();
         final String wsAddress = ((InetSocketAddress) wsChannelHandle.localAddress()).getAddress().getHostAddress();
 
@@ -543,7 +584,7 @@ public class Server {
         if (generate) {
             LOG.warn("Using generated self signed server certificate");
             Date begin = new Date();
-            Date end = new Date(begin.getTime() + 86400000);
+            Date end = new Date(begin.getTime() + TimeUnit.DAYS.toMillis(7));
             SelfSignedCertificate ssc = new SelfSignedCertificate("localhost", begin, end);
             ssl = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey());
         } else {
@@ -591,11 +632,11 @@ public class Server {
                 ch.pipeline().addLast("aggregator", new HttpObjectAggregator(65536));
                 ch.pipeline().addLast("chunker", new ChunkedWriteHandler());
                 final Cors corsCfg = config.getHttp().getCors();
-                final CorsConfig.Builder ccb;
+                final CorsConfigBuilder ccb;
                 if (corsCfg.isAllowAnyOrigin()) {
-                    ccb = new CorsConfig.Builder();
+                    ccb = CorsConfigBuilder.forAnyOrigin();
                 } else {
-                    ccb = new CorsConfig.Builder(corsCfg.getAllowedOrigins().stream().toArray(String[]::new));
+                    ccb = CorsConfigBuilder.forOrigins(corsCfg.getAllowedOrigins().stream().toArray(String[]::new));
                 }
                 if (corsCfg.isAllowNullOrigin()) {
                     ccb.allowNullOrigin();
@@ -610,7 +651,8 @@ public class Server {
                 ch.pipeline().addLast("cors", new CorsHandler(cors));
                 ch.pipeline().addLast("queryDecoder",
                         new timely.netty.http.HttpRequestDecoder(config.getSecurity(), config.getHttp()));
-                ch.pipeline().addLast("fileServer", new HttpStaticFileServerHandler());
+                ch.pipeline().addLast("fileServer", new HttpStaticFileServerHandler()
+                        .setIgnoreSslHandshakeErrors(config.getSecurity().getServerSsl().isUseGeneratedKeypair()));
                 ch.pipeline().addLast("strict", new StrictTransportHandler(config));
                 ch.pipeline().addLast("login", new X509LoginRequestHandler(config.getSecurity(), config.getHttp()));
                 ch.pipeline().addLast("doLogin",
@@ -623,7 +665,9 @@ public class Server {
                 ch.pipeline().addLast("version", new HttpVersionRequestHandler());
                 ch.pipeline().addLast("cache", new HttpCacheRequestHandler(dataStoreCache));
                 ch.pipeline().addLast("put", new HttpMetricPutHandler(dataStore));
-                ch.pipeline().addLast("error", new TimelyExceptionHandler());
+                ch.pipeline().addLast("error", new TimelyExceptionHandler()
+                        .setIgnoreSslHandshakeErrors(config.getSecurity().getServerSsl().isUseGeneratedKeypair()));
+
             }
         };
     }
@@ -668,7 +712,7 @@ public class Server {
                 ch.pipeline().addLast("sessionExtractor", new WebSocketFullRequestHandler());
                 ch.pipeline().addLast("idle-handler", new IdleStateHandler(conf.getWebsocket().getTimeout(), 0, 0));
                 ch.pipeline().addLast("ws-protocol",
-                        new WebSocketServerProtocolHandler(WS_PATH, null, true, 65536, true));
+                        new WebSocketServerProtocolHandler(WS_PATH, null, true, 65536, false, true));
                 ch.pipeline().addLast("wsDecoder", new WebSocketRequestDecoder(config.getSecurity()));
                 ch.pipeline().addLast("aggregators", new WSAggregatorsRequestHandler());
                 ch.pipeline().addLast("metrics", new WSMetricsRequestHandler(config));

server/src/main/java/timely/StandaloneServer.java

@@ -52,7 +52,8 @@ public class StandaloneServer extends Server {
             System.exit(1);
         }
 
-        Configuration conf = initializeConfiguration(args);
+        StandaloneServer.applicationContext = initializeContext(args);
+        Configuration conf = StandaloneServer.applicationContext.getBean(Configuration.class);
 
         File accumuloDir = new File(tmp, "accumulo");
         MiniAccumuloConfig macConfig = new MiniAccumuloConfig(accumuloDir, "secret");

server/src/main/java/timely/adapter/accumulo/MetaAdapter.java

@@ -0,0 +1,39 @@
+package timely.adapter.accumulo;
+
+import org.apache.accumulo.core.data.Key;
+import timely.api.model.Meta;
+import timely.model.Metric;
+
+/**
+ * Creates Accumulo data structures from {@link Metric}
+ */
+public class MetaAdapter {
+
+    public static Key createMetricKey(String metricName, Long timestamp) {
+        return new Key(Meta.METRIC_PREFIX + metricName, "", "", timestamp);
+    }
+
+    public static Key createTagKey(String metricName, String tagName, Long timestamp) {
+        return new Key(Meta.TAG_PREFIX + metricName, tagName, "", timestamp);
+    }
+
+    public static Key createValueKey(String metricName, String tagName, String tagValue, Long timestamp) {
+        return new Key(Meta.VALUE_PREFIX + metricName, tagName, tagValue, timestamp);
+    }
+
+    public static Meta parse(Key key) {
+        String row = key.getRow().toString();
+        if (row.startsWith(Meta.METRIC_PREFIX)) {
+            return Meta.parse(key, null, Meta.METRIC_PREFIX);
+        } else if (row.startsWith(Meta.TAG_PREFIX)) {
+            return Meta.parse(key, null, Meta.TAG_PREFIX);
+        } else if (row.startsWith(Meta.VALUE_PREFIX)) {
+            return Meta.parse(key, null, Meta.VALUE_PREFIX);
+        }
+        throw new IllegalStateException("Invalid key in meta " + key.toString());
+    }
+
+    public static String decodeRowKey(Key key) {
+        return parse(key).getMetric();
+    }
+}

server/src/main/java/timely/api/model/Meta.java

@@ -5,6 +5,10 @@ import java.util.List;
 
 import org.apache.accumulo.core.data.Key;
 import org.apache.accumulo.core.data.Value;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.commons.lang3.builder.CompareToBuilder;
+import org.apache.commons.lang3.builder.EqualsBuilder;
+import org.apache.commons.lang3.builder.HashCodeBuilder;
 
 public class Meta implements Comparable<Meta> {
 
@@ -49,14 +53,44 @@ public class Meta implements Comparable<Meta> {
 
     public List<Key> toKeys() {
         List<Key> keys = new ArrayList<>();
-        keys.add(new Key(METRIC_PREFIX + metric));
-        keys.add(new Key(TAG_PREFIX + metric, tagKey));
-        keys.add(new Key(VALUE_PREFIX + metric, tagKey, tagValue));
+        if (StringUtils.isNotBlank(metric)) {
+            keys.add(new Key(METRIC_PREFIX + metric));
+        }
+        if (StringUtils.isNotBlank(tagKey)) {
+            keys.add(new Key(TAG_PREFIX + metric, tagKey));
+        }
+        if (StringUtils.isNotBlank(tagKey) && StringUtils.isNotBlank(tagValue)) {
+            keys.add(new Key(VALUE_PREFIX + metric, tagKey, tagValue));
+        }
         return keys;
     }
 
-    public static Meta parse(Key k, Value v) {
-        return Meta.parse(k, v, METRIC_PREFIX);
+    public static String prefix(Key key) {
+        String row = key.getRow().toString();
+        if (row.startsWith(Meta.METRIC_PREFIX)) {
+            return Meta.METRIC_PREFIX;
+        } else if (row.startsWith(Meta.TAG_PREFIX)) {
+            return Meta.TAG_PREFIX;
+        } else if (row.startsWith(Meta.VALUE_PREFIX)) {
+            return Meta.VALUE_PREFIX;
+        }
+        throw new IllegalStateException("Invalid key in meta " + key.toString());
+    }
+
+    public static Meta parse(Key key) {
+        return parse(key, null);
+    }
+
+    public static Meta parse(Key key, Value value) {
+        String row = key.getRow().toString();
+        if (row.startsWith(Meta.METRIC_PREFIX)) {
+            return Meta.parse(key, value, Meta.METRIC_PREFIX);
+        } else if (row.startsWith(Meta.TAG_PREFIX)) {
+            return Meta.parse(key, value, Meta.TAG_PREFIX);
+        } else if (row.startsWith(Meta.VALUE_PREFIX)) {
+            return Meta.parse(key, value, Meta.VALUE_PREFIX);
+        }
+        throw new IllegalStateException("Invalid key in meta " + key.toString());
     }
 
     public static Meta parse(Key k, Value v, String prefix) {
@@ -73,39 +107,25 @@ public class Meta implements Comparable<Meta> {
 
     @Override
     public int hashCode() {
-        final int prime = 31;
-        int result = 1;
-        result = prime * result + ((metric == null) ? 0 : metric.hashCode());
-        result = prime * result + ((tagKey == null) ? 0 : tagKey.hashCode());
-        result = prime * result + ((tagValue == null) ? 0 : tagValue.hashCode());
-        return result;
+        HashCodeBuilder builder = new HashCodeBuilder();
+        builder.append(metric);
+        builder.append(tagKey);
+        builder.append(tagValue);
+        return builder.toHashCode();
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (this == obj)
-            return true;
-        if (obj == null)
+    public boolean equals(Object o) {
+        if (o instanceof Meta) {
+            Meta obj = (Meta) o;
+            EqualsBuilder builder = new EqualsBuilder();
+            builder.append(this.metric, obj.metric);
+            builder.append(this.tagKey, obj.tagKey);
+            builder.append(this.tagValue, obj.tagValue);
+            return builder.isEquals();
+        } else {
             return false;
-        if (getClass() != obj.getClass())
-            return false;
-        Meta other = (Meta) obj;
-        if (metric == null) {
-            if (other.metric != null)
-                return false;
-        } else if (!metric.equals(other.metric))
-            return false;
-        if (tagKey == null) {
-            if (other.tagKey != null)
-                return false;
-        } else if (!tagKey.equals(other.tagKey))
-            return false;
-        if (tagValue == null) {
-            if (other.tagValue != null)
-                return false;
-        } else if (!tagValue.equals(other.tagValue))
-            return false;
-        return true;
+        }
     }
 
     @Override
@@ -115,15 +135,10 @@ public class Meta implements Comparable<Meta> {
 
     @Override
     public int compareTo(Meta o) {
-        int result = metric.compareTo(o.metric);
-        if (result != 0) {
-            return result;
-        }
-        result = tagKey.compareTo(o.tagKey);
-        if (result != 0) {
-            return result;
-        }
-        return tagValue.compareTo(o.tagValue);
+        CompareToBuilder builder = new CompareToBuilder();
+        builder.append(this.metric, o.metric);
+        builder.append(this.tagKey, o.tagKey);
+        builder.append(this.tagValue, o.tagValue);
+        return builder.toComparison();
     }
-
 }

server/src/main/java/timely/api/request/TcpRequest.java

@@ -4,8 +4,6 @@ public interface TcpRequest extends Request {
 
     /**
      * Parse a line of text received and populate this object
-     * 
-     * @param line
      */
     public void parse(String line);
 

server/src/main/java/timely/api/request/UdpRequest.java

@@ -4,8 +4,6 @@ public interface UdpRequest {
 
     /**
      * Parse a line of text received and populate this object
-     * 
-     * @param line
      */
     public void parse(String line);
 

server/src/main/java/timely/api/response/timeseries/MetricsResponse.java

@@ -18,7 +18,7 @@ import com.fasterxml.jackson.databind.node.ObjectNode;
 import io.netty.buffer.Unpooled;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
@@ -129,8 +129,8 @@ public class MetricsResponse {
         }
         FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK,
                 Unpooled.copiedBuffer(buf));
-        response.headers().set(Names.CONTENT_TYPE, responseType);
-        response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+        response.headers().set(HttpHeaderNames.CONTENT_TYPE, responseType);
+        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
         return response;
     }
 
@@ -156,8 +156,10 @@ public class MetricsResponse {
         b.append(TR_END);
         String prevMetric = null;
         StringBuilder tags = new StringBuilder();
+        Map<String, Long> tagMap = new HashMap<>();
         for (Meta m : tree) {
             if (prevMetric != null && !m.getMetric().equals(prevMetric)) {
+                tagMap.clear();
                 b.append(TR_START);
                 b.append(TD_START).append(prevMetric).append(TD_END);
                 b.append(TD_START).append(tags.toString()).append(TD_END);
@@ -168,8 +170,12 @@ public class MetricsResponse {
             if (prevMetric == null) {
                 prevMetric = m.getMetric();
             }
+            long numValues = tagMap.getOrDefault(m.getTagKey(), 0l);
             if (!(this.ignoredTags.contains(m.getTagKey()))) {
-                tags.append(m.getTagKey()).append("=").append(m.getTagValue()).append(" ");
+                if (numValues <= conf.getMetaCache().getMaxTagValues()) {
+                    tags.append(m.getTagKey()).append("=").append(m.getTagValue()).append(" ");
+                    tagMap.put(m.getTagKey(), ++numValues);
+                }
             }
         }
         b.append(TR_START);

server/src/main/java/timely/auth/AuthenticationService.java

@@ -43,9 +43,13 @@ public class AuthenticationService {
         try {
             springContext = new ClassPathXmlApplicationContext("security.xml");
             authManager = springContext.getBean("authenticationManager", AuthenticationManager.class);
-            requiredRoles = springContext.getBean("requiredRoles", List.class);
+            @SuppressWarnings("unchecked")
+            List<String> uncheckedRoles = springContext.getBean("requiredRoles", List.class);
+            requiredRoles = uncheckedRoles;
             requiredRoles.removeIf(String::isEmpty);
-            requiredAuths = springContext.getBean("requiredAuths", List.class);
+            @SuppressWarnings("unchecked")
+            List<String> uncheckedAuths = springContext.getBean("requiredAuths", List.class);
+            requiredAuths = uncheckedAuths;
             requiredAuths.removeIf(String::isEmpty);
         } catch (BeansException e) {
             throw new ServiceConfigurationError("Error setting up Authentication objects: " + e.getMessage(),

server/src/main/java/timely/auth/ScannerBaseDelegate.java

@@ -16,8 +16,6 @@ import org.apache.accumulo.core.data.Value;
 import org.apache.accumulo.core.data.thrift.IterInfo;
 import org.apache.accumulo.core.security.Authorizations;
 import org.apache.hadoop.io.Text;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * A simple wrapper around a {@link ScannerBase} that overrides the methods that
@@ -27,7 +25,6 @@ import org.slf4j.LoggerFactory;
  */
 public class ScannerBaseDelegate implements ScannerBase {
 
-    private static final Logger log = LoggerFactory.getLogger(ScannerBaseDelegate.class);
     private static final String SYSTEM_ITERATOR_NAME_PREFIX = "sys_";
 
     protected final ScannerBase delegate;
@@ -139,10 +136,11 @@ public class ScannerBaseDelegate implements ScannerBase {
     @Override
     public void clearScanIterators() {
         if (delegate instanceof ScannerOptions) {
-            ScannerOptionsHelper opts = new ScannerOptionsHelper((ScannerOptions) delegate);
-            for (IteratorSetting iteratorSetting : opts.getIterators()) {
-                if (!iteratorSetting.getName().startsWith(SYSTEM_ITERATOR_NAME_PREFIX)) {
-                    delegate.removeScanIterator(iteratorSetting.getName());
+            try (ScannerOptionsHelper opts = new ScannerOptionsHelper((ScannerOptions) delegate)) {
+                for (IteratorSetting iteratorSetting : opts.getIterators()) {
+                    if (!iteratorSetting.getName().startsWith(SYSTEM_ITERATOR_NAME_PREFIX)) {
+                        delegate.removeScanIterator(iteratorSetting.getName());
+                    }
                 }
             }
         } else {

server/src/main/java/timely/auth/SubjectIssuerDNPair.java

@@ -13,6 +13,7 @@ import timely.auth.util.ProxiedEntityUtils;
  */
 public class SubjectIssuerDNPair implements Serializable {
 
+    private static final long serialVersionUID = 1L;
     private final String subjectDN;
     private final String issuerDN;
 

server/src/main/java/timely/auth/TimelyPrincipal.java

@@ -29,6 +29,7 @@ import timely.auth.util.DnUtils;
 @XmlAccessorType(XmlAccessType.NONE)
 public class TimelyPrincipal implements Principal, Serializable {
 
+    private static final long serialVersionUID = 1L;
     private final String username;
     private final TimelyUser primaryUser;
     @XmlElement
@@ -103,7 +104,7 @@ public class TimelyPrincipal implements Principal, Serializable {
 
     public Set<String> getProxyServers() {
 
-        // @formatter:off
+    // @formatter:off
         Set<String> proxyServers = getProxiedUsers().stream()
                 .filter(u -> u.getUserType() == TimelyUser.UserType.SERVER)
                 .map(TimelyUser::getDn)

server/src/main/java/timely/auth/TimelyUser.java

@@ -20,6 +20,8 @@ import timely.auth.util.DnUtils;
  */
 public class TimelyUser implements Serializable {
 
+    private static final long serialVersionUID = 1L;
+
     public enum UserType {
         USER, SERVER
     }

server/src/main/java/timely/auth/util/HttpHeaderUtils.java

@@ -13,7 +13,9 @@ public class HttpHeaderUtils {
         Multimap<String, String> headerMultimap = HashMultimap.create();
         if (headers != null) {
             for (Map.Entry<String, String> e : headers.entries()) {
-                headerMultimap.put(e.getKey(), e.getValue());
+                // lower case for HTTP/2 compatibility; even for HTTP/1, these were always
+                // case-insensitive
+                headerMultimap.put(e.getKey().toLowerCase(), e.getValue());
             }
         }
         return headerMultimap;
@@ -22,6 +24,9 @@ public class HttpHeaderUtils {
     public static String getSingleHeader(Multimap<String, String> headers, String headerName, boolean enforceOneValue)
             throws IllegalArgumentException {
         String value = null;
+        // lower case for HTTP/2 compatibility; even for HTTP/1, these were always
+        // case-insensitive
+        headerName = headerName.toLowerCase();
         Collection<String> values = (headers == null) ? null : headers.get(headerName);
         if (values != null && !values.isEmpty()) {
             if (values.size() > 1 && enforceOneValue) {

server/src/main/java/timely/configuration/Accumulo.java

@@ -1,8 +1,8 @@
 package timely.configuration;
 
 import javax.validation.Valid;
+import javax.validation.constraints.NotBlank;
 
-import org.hibernate.validator.constraints.NotBlank;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 
 public class Accumulo {
@@ -12,6 +12,8 @@ public class Accumulo {
     @NotBlank
     private String instanceName;
     @NotBlank
+    private String zookeeperTimeout = "120s";
+    @NotBlank
     private String username;
     @NotBlank
     private String password;
@@ -46,6 +48,14 @@ public class Accumulo {
         this.instanceName = instanceName;
     }
 
+    public String getZookeeperTimeout() {
+        return zookeeperTimeout;
+    }
+
+    public void setZookeeperTimeout(String zookeeperTimeout) {
+        this.zookeeperTimeout = zookeeperTimeout;
+    }
+
     public String getUsername() {
         return username;
     }

server/src/main/java/timely/configuration/Cache.java

@@ -13,6 +13,7 @@ public class Cache {
     private List<String> nonCachedMetrics = new ArrayList<>();
     private long maxUniqueTagSets = 50000;
     private long flushInterval = 5000;
+    private long staleCacheExpiration = 1800000;
 
     public HashMap<String, Integer> getMetricAgeOffHours() {
         return metricAgeOffHours;
@@ -57,4 +58,12 @@ public class Cache {
     public void setFlushInterval(long flushInterval) {
         this.flushInterval = flushInterval;
     }
+
+    public long getStaleCacheExpiration() {
+        return staleCacheExpiration;
+    }
+
+    public void setStaleCacheExpiration(long staleCacheExpiration) {
+        this.staleCacheExpiration = staleCacheExpiration;
+    }
 }

server/src/main/java/timely/configuration/Http.java

@@ -1,9 +1,9 @@
 package timely.configuration;
 
 import javax.validation.Valid;
+import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.NotNull;
 
-import org.hibernate.validator.constraints.NotBlank;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 
 public class Http {

server/src/main/java/timely/configuration/Server.java

@@ -1,9 +1,8 @@
 package timely.configuration;
 
+import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.NotNull;
 
-import org.hibernate.validator.constraints.NotBlank;
-
 public class Server {
 
     @NotBlank
@@ -42,8 +41,6 @@ public class Server {
     /**
      * Time to wait (in seconds) for connections to finish and to make sure no new
      * connections happen before shutting down Netty event loop groups.
-     *
-     * @return
      */
     public int getShutdownQuietPeriod() {
         return this.shutdownQuietPeriod;

server/src/main/java/timely/configuration/Websocket.java

@@ -1,9 +1,8 @@
 package timely.configuration;
 
+import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.NotNull;
 
-import org.hibernate.validator.constraints.NotBlank;
-
 public class Websocket {
 
     @NotBlank

server/src/main/java/timely/netty/http/HttpCacheRequestHandler.java

@@ -5,7 +5,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import timely.api.request.CacheRequest;
@@ -35,8 +35,8 @@ public class HttpCacheRequestHandler extends SimpleChannelInboundHandler<CacheRe
         }
         FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK,
                 Unpooled.copiedBuffer(buf));
-        response.headers().set(Names.CONTENT_TYPE, Constants.JSON_TYPE);
-        response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+        response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.JSON_TYPE);
+        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
         sendResponse(ctx, response);
     }
 

server/src/main/java/timely/netty/http/HttpMetricPutHandler.java

@@ -5,7 +5,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import org.slf4j.Logger;
@@ -35,8 +35,8 @@ public class HttpMetricPutHandler extends SimpleChannelInboundHandler<MetricRequ
         }
         FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK,
                 Unpooled.EMPTY_BUFFER);
-        response.headers().set(Names.CONTENT_TYPE, Constants.JSON_TYPE);
-        response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+        response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.JSON_TYPE);
+        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
         sendResponse(ctx, response);
     }
 

server/src/main/java/timely/netty/http/HttpRequestDecoder.java

@@ -10,7 +10,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToMessageDecoder;
 import io.netty.handler.codec.http.FullHttpRequest;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpMethod;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.QueryStringDecoder;
@@ -52,7 +52,7 @@ public class HttpRequestDecoder extends MessageToMessageDecoder<FullHttpRequest>
 
     public static String getSessionId(FullHttpRequest msg) {
         Multimap<String, String> headers = HttpHeaderUtils.toMultimap(msg.headers());
-        Collection<String> cookies = headers.get(Names.COOKIE);
+        Collection<String> cookies = headers.get(HttpHeaderNames.COOKIE.toString());
         final StringBuilder buf = new StringBuilder();
         cookies.forEach(h -> {
             ServerCookieDecoder.STRICT.decode(h).forEach(c -> {
@@ -75,7 +75,7 @@ public class HttpRequestDecoder extends MessageToMessageDecoder<FullHttpRequest>
 
         LOG.trace(LOG_RECEIVED_REQUEST, msg);
 
-        final String uri = msg.getUri();
+        final String uri = msg.uri();
         final QueryStringDecoder decoder = new QueryStringDecoder(uri);
         if (decoder.path().equals(nonSecureRedirectAddress)) {
             out.add(new StrictTransportResponse());
@@ -87,10 +87,10 @@ public class HttpRequestDecoder extends MessageToMessageDecoder<FullHttpRequest>
 
         HttpRequest request;
         try {
-            if (msg.getMethod().equals(HttpMethod.GET)) {
+            if (msg.method().equals(HttpMethod.GET)) {
                 HttpGetRequest get = AnnotationResolver.getClassForHttpGet(decoder.path());
                 request = get.parseQueryParameters(decoder);
-            } else if (msg.getMethod().equals(HttpMethod.POST)) {
+            } else if (msg.method().equals(HttpMethod.POST)) {
                 HttpPostRequest post = AnnotationResolver.getClassForHttpPost(decoder.path());
                 String content = "";
                 ByteBuf body = msg.content();
@@ -101,8 +101,9 @@ public class HttpRequestDecoder extends MessageToMessageDecoder<FullHttpRequest>
             } else {
                 TimelyException e = new TimelyException(HttpResponseStatus.METHOD_NOT_ALLOWED.code(),
                         "unhandled method type", "");
-                e.addResponseHeader(Names.ALLOW, HttpMethod.GET.name() + "," + HttpMethod.POST.name());
-                LOG.warn("Unhandled HTTP request type {}", msg.getMethod());
+                e.addResponseHeader(HttpHeaderNames.ALLOW.toString(),
+                        HttpMethod.GET.name() + "," + HttpMethod.POST.name());
+                LOG.warn("Unhandled HTTP request type {}", msg.method());
                 throw e;
             }
             if (request instanceof AuthenticatedRequest) {

server/src/main/java/timely/netty/http/HttpStaticFileServerHandler.java

@@ -15,14 +15,14 @@
  */
 package timely.netty.http;
 
-import static io.netty.handler.codec.http.HttpHeaders.Names.CACHE_CONTROL;
-import static io.netty.handler.codec.http.HttpHeaders.Names.CONNECTION;
-import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE;
-import static io.netty.handler.codec.http.HttpHeaders.Names.DATE;
-import static io.netty.handler.codec.http.HttpHeaders.Names.EXPIRES;
-import static io.netty.handler.codec.http.HttpHeaders.Names.IF_MODIFIED_SINCE;
-import static io.netty.handler.codec.http.HttpHeaders.Names.LAST_MODIFIED;
-import static io.netty.handler.codec.http.HttpHeaders.Names.LOCATION;
+import static io.netty.handler.codec.http.HttpHeaderNames.CACHE_CONTROL;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONNECTION;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
+import static io.netty.handler.codec.http.HttpHeaderNames.DATE;
+import static io.netty.handler.codec.http.HttpHeaderNames.EXPIRES;
+import static io.netty.handler.codec.http.HttpHeaderNames.IF_MODIFIED_SINCE;
+import static io.netty.handler.codec.http.HttpHeaderNames.LAST_MODIFIED;
+import static io.netty.handler.codec.http.HttpHeaderNames.LOCATION;
 import static io.netty.handler.codec.http.HttpMethod.GET;
 import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
 import static io.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN;
@@ -48,6 +48,7 @@ import java.util.TimeZone;
 import java.util.regex.Pattern;
 
 import javax.activation.MimetypesFileTypeMap;
+import javax.net.ssl.SSLHandshakeException;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -59,9 +60,10 @@ import io.netty.handler.codec.http.DefaultHttpResponse;
 import io.netty.handler.codec.http.FullHttpRequest;
 import io.netty.handler.codec.http.FullHttpResponse;
 import io.netty.handler.codec.http.HttpChunkedInput;
-import io.netty.handler.codec.http.HttpHeaders;
+import io.netty.handler.codec.http.HttpHeaderValues;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.handler.codec.http.HttpUtil;
 import io.netty.handler.stream.ChunkedFile;
 import io.netty.util.CharsetUtil;
 import io.netty.util.internal.SystemPropertyUtil;
@@ -94,7 +96,7 @@ import timely.netty.Constants;
  * Request #1 Headers
  * ===================
  * GET /file1.txt HTTP/1.1
- * 
+ *
  * Response #1 Headers
  * ===================
  * HTTP/1.1 200 OK
@@ -102,12 +104,12 @@ import timely.netty.Constants;
  * Last-Modified:      Wed, 30 Jun 2010 21:36:48 GMT
  * Expires:            Tue, 01 Mar 2012 22:44:26 GMT
  * Cache-Control:      private, max-age=31536000
- * 
+ *
  * Request #2 Headers
  * ===================
  * GET /file1.txt HTTP/1.1
  * If-Modified-Since:  Wed, 30 Jun 2010 21:36:48 GMT
- * 
+ *
  * Response #2 Headers
  * ===================
  * HTTP/1.1 304 Not Modified
@@ -122,20 +124,21 @@ public class HttpStaticFileServerHandler extends SimpleChannelInboundHandler<Ful
     public static final String HTTP_DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz";
     public static final String HTTP_DATE_GMT_TIMEZONE = "GMT";
     public static final int HTTP_CACHE_SECONDS = 60;
+    private boolean ignoreSslHandshakeErrors = false;
 
     @Override
     public void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
-        if (!request.getDecoderResult().isSuccess()) {
+        if (!request.decoderResult().isSuccess()) {
             sendError(ctx, BAD_REQUEST);
             return;
         }
 
-        if (request.getMethod() != GET) {
+        if (request.method() != GET) {
             sendError(ctx, METHOD_NOT_ALLOWED);
             return;
         }
 
-        String uri = request.getUri();
+        String uri = request.uri();
         if (uri.startsWith("/favicon.ico")) {
             uri = uri.replaceFirst("\\/", "/webapp/");
         }
@@ -201,12 +204,12 @@ public class HttpStaticFileServerHandler extends SimpleChannelInboundHandler<Ful
         long fileLength = raf.length();
 
         HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
-        HttpHeaders.setContentLength(response, fileLength);
+        HttpUtil.setContentLength(response, fileLength);
         setContentTypeHeader(response, file);
         setDateAndCacheHeaders(response, file);
-        HttpHeaders.setTransferEncodingChunked(response);
-        if (HttpHeaders.isKeepAlive(request)) {
-            response.headers().set(CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
+        HttpUtil.setTransferEncodingChunked(response, true);
+        if (HttpUtil.isKeepAlive(request)) {
+            response.headers().set(CONNECTION, HttpHeaderValues.KEEP_ALIVE);
         }
 
         // Write the initial line and the header.
@@ -220,6 +223,10 @@ public class HttpStaticFileServerHandler extends SimpleChannelInboundHandler<Ful
 
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
+        // ignore SSLHandshakeException when using a self-signed server certificate
+        if (ignoreSslHandshakeErrors && cause.getCause() instanceof SSLHandshakeException) {
+            return;
+        }
         LOG.error("Error serving file", cause);
         if (ctx.channel().isActive()) {
             sendError(ctx, INTERNAL_SERVER_ERROR);
@@ -378,4 +385,9 @@ public class HttpStaticFileServerHandler extends SimpleChannelInboundHandler<Ful
         MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
         response.headers().set(CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath()));
     }
+
+    public HttpStaticFileServerHandler setIgnoreSslHandshakeErrors(boolean ignoreSslHandshakeErrors) {
+        this.ignoreSslHandshakeErrors = ignoreSslHandshakeErrors;
+        return this;
+    }
 }

server/src/main/java/timely/netty/http/HttpVersionRequestHandler.java

@@ -7,7 +7,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import timely.api.request.VersionRequest;
@@ -20,8 +20,8 @@ public class HttpVersionRequestHandler extends SimpleChannelInboundHandler<Versi
     protected void channelRead0(ChannelHandlerContext ctx, VersionRequest v) throws Exception {
         FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK,
                 Unpooled.copiedBuffer(VersionRequest.VERSION.getBytes(StandardCharsets.UTF_8)));
-        response.headers().set(Names.CONTENT_TYPE, Constants.TEXT_TYPE);
-        response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+        response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.TEXT_TYPE);
+        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
         sendResponse(ctx, response);
     }
 

server/src/main/java/timely/netty/http/NonSslRedirectHandler.java

@@ -6,7 +6,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseEncoder;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
@@ -51,7 +51,7 @@ public class NonSslRedirectHandler extends OptionalSslHandler implements TimelyH
                 LOG.trace("Received non-SSL request, returning redirect");
                 FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,
                         HttpResponseStatus.MOVED_PERMANENTLY, Unpooled.EMPTY_BUFFER);
-                response.headers().set(Names.LOCATION, redirectAddress);
+                response.headers().set(HttpHeaderNames.LOCATION, redirectAddress);
                 LOG.trace(Constants.LOG_RETURNING_RESPONSE, response);
                 encoder.write(ctx, response, ctx.voidPromise());
                 ctx.flush();

server/src/main/java/timely/netty/http/TimelyExceptionHandler.java

@@ -1,5 +1,7 @@
 package timely.netty.http;
 
+import javax.net.ssl.SSLHandshakeException;
+
 import io.netty.channel.ChannelHandler.Sharable;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
@@ -12,6 +14,7 @@ import timely.api.response.TimelyException;
 public class TimelyExceptionHandler extends SimpleChannelInboundHandler<TimelyException> implements TimelyHttpHandler {
 
     private static final Logger LOG = LoggerFactory.getLogger(TimelyExceptionHandler.class);
+    private boolean ignoreSslHandshakeErrors = false;
 
     @Override
     protected void channelRead0(ChannelHandlerContext ctx, TimelyException msg) throws Exception {
@@ -20,6 +23,10 @@ public class TimelyExceptionHandler extends SimpleChannelInboundHandler<TimelyEx
 
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
+        // ignore SSLHandshakeException when using a self-signed server certificate
+        if (ignoreSslHandshakeErrors && cause.getCause() instanceof SSLHandshakeException) {
+            return;
+        }
         LOG.error("Unhandled exception in pipeline", cause);
         if (cause instanceof TimelyException) {
             this.sendHttpError(ctx, (TimelyException) cause);
@@ -32,4 +39,8 @@ public class TimelyExceptionHandler extends SimpleChannelInboundHandler<TimelyEx
         }
     }
 
+    public TimelyExceptionHandler setIgnoreSslHandshakeErrors(boolean ignoreSslHandshakeErrors) {
+        this.ignoreSslHandshakeErrors = ignoreSslHandshakeErrors;
+        return this;
+    }
 }

server/src/main/java/timely/netty/http/TimelyHttpHandler.java

@@ -6,7 +6,7 @@ import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import org.slf4j.Logger;
@@ -25,8 +25,8 @@ public interface TimelyHttpHandler {
                 .writeValueAsBytes("ResponseCode: " + e.getCode() + " Message: " + e.getMessage());
         FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,
                 HttpResponseStatus.valueOf(e.getCode()), Unpooled.copiedBuffer(buf));
-        response.headers().set(Names.CONTENT_TYPE, Constants.JSON_TYPE);
-        response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+        response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.JSON_TYPE);
+        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
         e.getResponseHeaders().entrySet().forEach(entry -> response.headers().set(entry.getKey(), entry.getValue()));
         // Send the error response
         sendResponse(ctx, response);

server/src/main/java/timely/netty/http/auth/TimelyAuthenticationToken.java

@@ -17,9 +17,10 @@ import timely.auth.util.HttpHeaderUtils;
 
 public class TimelyAuthenticationToken extends PreAuthenticatedAuthenticationToken {
 
+    private static final long serialVersionUID = 1L;
     private static final Logger LOG = LoggerFactory.getLogger(TimelyAuthenticationToken.class);
-    public static final String PROXIED_ENTITIES_HEADER = "X-ProxiedEntitiesChain";
-    public static final String PROXIED_ISSUERS_HEADER = "X-ProxiedIssuersChain";
+    public static final String PROXIED_ENTITIES_HEADER = "x-proxiedentitieschain";
+    public static final String PROXIED_ISSUERS_HEADER = "x-proxiedissuerschain";
 
     private Multimap<String, String> httpHeaders = null;
     private X509Certificate clientCert = null;

server/src/main/java/timely/netty/http/auth/TimelyLoginRequestHandler.java

@@ -8,7 +8,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import io.netty.handler.codec.http.cookie.DefaultCookie;
@@ -43,22 +43,22 @@ public abstract class TimelyLoginRequestHandler<T> extends SimpleChannelInboundH
                     principal.getPrimaryUser().getDn().subjectDN());
             String sessionIdEncoded = URLEncoder.encode(sessionId, StandardCharsets.UTF_8.name());
             FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
-            response.headers().set(Names.CONTENT_TYPE, Constants.JSON_TYPE);
-            response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+            response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.JSON_TYPE);
+            response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
             DefaultCookie cookie = new DefaultCookie(Constants.COOKIE_NAME, sessionIdEncoded);
             cookie.setDomain(domain);
             cookie.setMaxAge(maxAge);
             cookie.setPath("/");
             cookie.setHttpOnly(true);
             cookie.setSecure(true);
-            response.headers().set(Names.SET_COOKIE, ServerCookieEncoder.STRICT.encode(cookie));
+            response.headers().set(HttpHeaderNames.SET_COOKIE, ServerCookieEncoder.STRICT.encode(cookie));
             sendResponse(ctx, response);
         } catch (Exception e) {
             LOG.error("Login failure", e);
             FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,
                     HttpResponseStatus.UNAUTHORIZED);
-            response.headers().set(Names.CONTENT_TYPE, Constants.JSON_TYPE);
-            response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+            response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.JSON_TYPE);
+            response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
             sendResponse(ctx, response);
         }
 

server/src/main/java/timely/netty/http/timeseries/HttpAggregatorsRequestHandler.java

@@ -5,7 +5,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import timely.api.request.timeseries.AggregatorsRequest;
@@ -22,8 +22,8 @@ public class HttpAggregatorsRequestHandler extends SimpleChannelInboundHandler<A
         byte[] buf = JsonUtil.getObjectMapper().writeValueAsBytes(AggregatorsResponse.RESPONSE);
         FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK,
                 Unpooled.copiedBuffer(buf));
-        response.headers().set(Names.CONTENT_TYPE, Constants.JSON_TYPE);
-        response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+        response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.JSON_TYPE);
+        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
         sendResponse(ctx, response);
     }
 

server/src/main/java/timely/netty/http/timeseries/HttpMetricsRequestHandler.java

@@ -2,7 +2,7 @@ package timely.netty.http.timeseries;
 
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import timely.api.request.timeseries.MetricsRequest;
 import timely.api.response.timeseries.MetricsResponse;
 import timely.configuration.Configuration;
@@ -20,7 +20,7 @@ public class HttpMetricsRequestHandler extends SimpleChannelInboundHandler<Metri
     @Override
     protected void channelRead0(ChannelHandlerContext ctx, MetricsRequest msg) throws Exception {
         MetricsResponse r = new MetricsResponse(conf);
-        String acceptHeader = msg.getRequestHeader(Names.ACCEPT);
+        String acceptHeader = msg.getRequestHeader(HttpHeaderNames.ACCEPT.toString());
         sendResponse(ctx, r.toHttpResponse(acceptHeader));
     }
 

server/src/main/java/timely/netty/http/timeseries/HttpQueryRequestHandler.java

@@ -5,7 +5,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.handler.codec.http.DefaultFullHttpResponse;
 import io.netty.handler.codec.http.FullHttpResponse;
-import io.netty.handler.codec.http.HttpHeaders.Names;
+import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponseStatus;
 import io.netty.handler.codec.http.HttpVersion;
 import org.slf4j.Logger;
@@ -42,8 +42,8 @@ public class HttpQueryRequestHandler extends SimpleChannelInboundHandler<QueryRe
         }
         FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK,
                 Unpooled.copiedBuffer(buf));
-        response.headers().set(Names.CONTENT_TYPE, Constants.JSON_TYPE);
-        response.headers().set(Names.CONTENT_LENGTH, response.content().readableBytes());
+        response.headers().set(HttpHeaderNames.CONTENT_TYPE, Constants.JSON_TYPE);
+        response.headers().set(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
         sendResponse(ctx, response);
     }