gecko-dev/services/metrics/providermanager.jsm

562 lines
18 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef MERGED_COMPARTMENT
"use strict";
this.EXPORTED_SYMBOLS = ["ProviderManager"];
const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
Cu.import("resource://gre/modules/services/metrics/dataprovider.jsm");
#endif
Cu.import("resource://gre/modules/Promise.jsm");
Cu.import("resource://gre/modules/Task.jsm");
Cu.import("resource://gre/modules/Log.jsm");
Cu.import("resource://services-common/utils.js");
/**
* Handles and coordinates the collection of metrics data from providers.
*
* This provides an interface for managing `Metrics.Provider` instances. It
* provides APIs for bulk collection of data.
*/
this.ProviderManager = function (storage) {
this._log = Log.repository.getLogger("Services.Metrics.ProviderManager");
this._providers = new Map();
this._storage = storage;
this._providerInitQueue = [];
this._providerInitializing = false;
this._pullOnlyProviders = {};
this._pullOnlyProvidersRegisterCount = 0;
this._pullOnlyProvidersState = this.PULL_ONLY_NOT_REGISTERED;
this._pullOnlyProvidersCurrentPromise = null;
// Callback to allow customization of providers after they are constructed
// but before they call out into their initialization code.
this.onProviderInit = null;
}
this.ProviderManager.prototype = Object.freeze({
PULL_ONLY_NOT_REGISTERED: "none",
PULL_ONLY_REGISTERING: "registering",
PULL_ONLY_UNREGISTERING: "unregistering",
PULL_ONLY_REGISTERED: "registered",
get providers() {
let providers = [];
for (let [name, entry] of this._providers) {
providers.push(entry.provider);
}
return providers;
},
/**
* Obtain a provider from its name.
*/
getProvider: function (name) {
let provider = this._providers.get(name);
if (!provider) {
return null;
}
return provider.provider;
},
/**
* Registers providers from a category manager category.
*
* This examines the specified category entries and registers found
* providers.
*
* Category entries are essentially JS modules and the name of the symbol
* within that module that is a `Metrics.Provider` instance.
*
* The category entry name is the name of the JS type for the provider. The
* value is the resource:// URI to import which makes this type available.
*
* Example entry:
*
* FooProvider resource://gre/modules/foo.jsm
*
* One can register entries in the application's .manifest file. e.g.
*
* category healthreport-js-provider-default FooProvider resource://gre/modules/foo.jsm
* category healthreport-js-provider-nightly EyeballProvider resource://gre/modules/eyeball.jsm
*
* Then to load them:
*
* let reporter = getHealthReporter("healthreport.");
* reporter.registerProvidersFromCategoryManager("healthreport-js-provider-default");
*
* If the category has no defined members, this call has no effect, and no error is raised.
*
* @param category
* (string) Name of category from which to query and load.
* @param providerDiagnostic
* (function) Optional, called with the name of the provider currently being initialized.
* @return a newly spawned Task.
*/
registerProvidersFromCategoryManager: function (category, providerDiagnostic) {
this._log.info("Registering providers from category: " + category);
let cm = Cc["@mozilla.org/categorymanager;1"]
.getService(Ci.nsICategoryManager);
let promiseList = [];
let enumerator = cm.enumerateCategory(category);
while (enumerator.hasMoreElements()) {
let entry = enumerator.getNext()
.QueryInterface(Ci.nsISupportsCString)
.toString();
let uri = cm.getCategoryEntry(category, entry);
this._log.info("Attempting to load provider from category manager: " +
entry + " from " + uri);
try {
let ns = {};
Cu.import(uri, ns);
let promise = this.registerProviderFromType(ns[entry]);
if (promise) {
promiseList.push({name: entry, promise: promise});
}
} catch (ex) {
this._recordProviderError(entry,
"Error registering provider from category manager",
ex);
continue;
}
}
return Task.spawn(function* wait() {
for (let entry of promiseList) {
if (providerDiagnostic) {
providerDiagnostic(entry.name);
}
yield entry.promise;
}
});
},
/**
* Registers a `MetricsProvider` with this manager.
*
* Once a `MetricsProvider` is registered, data will be collected from it
* whenever we collect data.
*
* The returned value is a promise that will be resolved once registration
* is complete.
*
* Providers are initialized as part of registration by calling
* provider.init().
*
* @param provider
* (Metrics.Provider) The provider instance to register.
*
* @return Promise<null>
*/
registerProvider: function (provider) {
// We should perform an instanceof check here. However, due to merged
// compartments, the Provider type may belong to one of two JSMs
// isinstance gets confused depending on which module Provider comes
// from. Some code references Provider from dataprovider.jsm; others from
// Metrics.jsm.
if (!provider.name) {
throw new Error("Provider is not valid: does not have a name.");
}
if (this._providers.has(provider.name)) {
return CommonUtils.laterTickResolvingPromise();
}
let deferred = Promise.defer();
this._providerInitQueue.push([provider, deferred]);
if (this._providerInitQueue.length == 1) {
this._popAndInitProvider();
}
return deferred.promise;
},
/**
* Registers a provider from its constructor function.
*
* If the provider is pull-only, it will be stashed away and
* initialized later. Null will be returned.
*
* If it is not pull-only, it will be initialized immediately and a
* promise will be returned. The promise will be resolved when the
* provider has finished initializing.
*/
registerProviderFromType: function (type) {
let proto = type.prototype;
if (proto.pullOnly) {
this._log.info("Provider is pull-only. Deferring initialization: " +
proto.name);
this._pullOnlyProviders[proto.name] = type;
return null;
}
let provider = this._initProviderFromType(type);
return this.registerProvider(provider);
},
/**
* Initializes a provider from its type.
*
* This is how a constructor function should be turned into a provider
* instance.
*
* A side-effect is the provider is registered with the manager.
*/
_initProviderFromType: function (type) {
let provider = new type();
if (this.onProviderInit) {
this.onProviderInit(provider);
}
return provider;
},
/**
* Remove a named provider from the manager.
*
* It is the caller's responsibility to shut down the provider
* instance.
*/
unregisterProvider: function (name) {
this._providers.delete(name);
},
/**
* Ensure that pull-only providers are registered.
*/
ensurePullOnlyProvidersRegistered: function () {
let state = this._pullOnlyProvidersState;
this._pullOnlyProvidersRegisterCount++;
if (state == this.PULL_ONLY_REGISTERED) {
this._log.debug("Requested pull-only provider registration and " +
"providers are already registered.");
return CommonUtils.laterTickResolvingPromise();
}
// If we're in the process of registering, chain off that request.
if (state == this.PULL_ONLY_REGISTERING) {
this._log.debug("Requested pull-only provider registration and " +
"registration is already in progress.");
return this._pullOnlyProvidersCurrentPromise;
}
this._log.debug("Pull-only provider registration requested.");
// A side-effect of setting this is that an active unregistration will
// effectively short circuit and finish as soon as the in-flight
// unregistration (if any) finishes.
this._pullOnlyProvidersState = this.PULL_ONLY_REGISTERING;
let inFlightPromise = this._pullOnlyProvidersCurrentPromise;
this._pullOnlyProvidersCurrentPromise =
Task.spawn(function registerPullProviders() {
if (inFlightPromise) {
this._log.debug("Waiting for in-flight pull-only provider activity " +
"to finish before registering.");
try {
yield inFlightPromise;
} catch (ex) {
this._log.warn("Error when waiting for existing pull-only promise: " +
CommonUtils.exceptionStr(ex));
}
}
for each (let providerType in this._pullOnlyProviders) {
// Short-circuit if we're no longer registering.
if (this._pullOnlyProvidersState != this.PULL_ONLY_REGISTERING) {
this._log.debug("Aborting pull-only provider registration.");
break;
}
try {
let provider = this._initProviderFromType(providerType);
// This is a no-op if the provider is already registered. So, the
// only overhead is constructing an instance. This should be cheap
// and isn't worth optimizing.
yield this.registerProvider(provider);
} catch (ex) {
this._recordProviderError(providerType.prototype.name,
"Error registering pull-only provider",
ex);
}
}
// It's possible we changed state while registering. Only mark as
// registered if we didn't change state.
if (this._pullOnlyProvidersState == this.PULL_ONLY_REGISTERING) {
this._pullOnlyProvidersState = this.PULL_ONLY_REGISTERED;
this._pullOnlyProvidersCurrentPromise = null;
}
}.bind(this));
return this._pullOnlyProvidersCurrentPromise;
},
ensurePullOnlyProvidersUnregistered: function () {
let state = this._pullOnlyProvidersState;
// If we're not registered, this is a no-op.
if (state == this.PULL_ONLY_NOT_REGISTERED) {
this._log.debug("Requested pull-only provider unregistration but none " +
"are registered.");
return CommonUtils.laterTickResolvingPromise();
}
// If we're currently unregistering, recycle the promise from last time.
if (state == this.PULL_ONLY_UNREGISTERING) {
this._log.debug("Requested pull-only provider unregistration and " +
"unregistration is in progress.");
this._pullOnlyProvidersRegisterCount =
Math.max(0, this._pullOnlyProvidersRegisterCount - 1);
return this._pullOnlyProvidersCurrentPromise;
}
// We ignore this request while multiple entities have requested
// registration because we don't want a request from an "inner,"
// short-lived request to overwrite the desire of the "parent,"
// longer-lived request.
if (this._pullOnlyProvidersRegisterCount > 1) {
this._log.debug("Requested pull-only provider unregistration while " +
"other callers still want them registered. Ignoring.");
this._pullOnlyProvidersRegisterCount--;
return CommonUtils.laterTickResolvingPromise();
}
// We are either fully registered or registering with a single consumer.
// In both cases we are authoritative and can commence unregistration.
this._log.debug("Pull-only providers being unregistered.");
this._pullOnlyProvidersRegisterCount =
Math.max(0, this._pullOnlyProvidersRegisterCount - 1);
this._pullOnlyProvidersState = this.PULL_ONLY_UNREGISTERING;
let inFlightPromise = this._pullOnlyProvidersCurrentPromise;
this._pullOnlyProvidersCurrentPromise =
Task.spawn(function unregisterPullProviders() {
if (inFlightPromise) {
this._log.debug("Waiting for in-flight pull-only provider activity " +
"to complete before unregistering.");
try {
yield inFlightPromise;
} catch (ex) {
this._log.warn("Error when waiting for existing pull-only promise: " +
CommonUtils.exceptionStr(ex));
}
}
for (let provider of this.providers) {
if (this._pullOnlyProvidersState != this.PULL_ONLY_UNREGISTERING) {
return;
}
if (!provider.pullOnly) {
continue;
}
this._log.info("Shutting down pull-only provider: " +
provider.name);
try {
yield provider.shutdown();
} catch (ex) {
this._recordProviderError(provider.name,
"Error when shutting down provider",
ex);
} finally {
this.unregisterProvider(provider.name);
}
}
if (this._pullOnlyProvidersState == this.PULL_ONLY_UNREGISTERING) {
this._pullOnlyProvidersState = this.PULL_ONLY_NOT_REGISTERED;
this._pullOnlyProvidersCurrentPromise = null;
}
}.bind(this));
return this._pullOnlyProvidersCurrentPromise;
},
_popAndInitProvider: function () {
if (!this._providerInitQueue.length || this._providerInitializing) {
return;
}
let [provider, deferred] = this._providerInitQueue.shift();
this._providerInitializing = true;
this._log.info("Initializing provider with storage: " + provider.name);
Task.spawn(function initProvider() {
try {
let result = yield provider.init(this._storage);
this._log.info("Provider successfully initialized: " + provider.name);
this._providers.set(provider.name, {
provider: provider,
constantsCollected: false,
});
deferred.resolve(result);
} catch (ex) {
this._recordProviderError(provider.name, "Failed to initialize", ex);
deferred.reject(ex);
} finally {
this._providerInitializing = false;
this._popAndInitProvider();
}
}.bind(this));
},
/**
* Collects all constant measurements from all providers.
*
* Returns a Promise that will be fulfilled once all data providers have
* provided their constant data. A side-effect of this promise fulfillment
* is that the manager is populated with the obtained collection results.
* The resolved value to the promise is this `ProviderManager` instance.
*
* @param providerDiagnostic
* (function) Optional, called with the name of the provider currently being initialized.
*/
collectConstantData: function (providerDiagnostic=null) {
let entries = [];
for (let [name, entry] of this._providers) {
if (entry.constantsCollected) {
this._log.trace("Provider has already provided constant data: " +
name);
continue;
}
entries.push(entry);
}
let onCollect = function (entry, result) {
entry.constantsCollected = true;
};
return this._callCollectOnProviders(entries, "collectConstantData",
onCollect, providerDiagnostic);
},
/**
* Calls collectDailyData on all providers.
*/
collectDailyData: function (providerDiagnostic=null) {
return this._callCollectOnProviders(this._providers.values(),
"collectDailyData",
null,
providerDiagnostic);
},
_callCollectOnProviders: function (entries, fnProperty, onCollect=null, providerDiagnostic=null) {
let promises = [];
for (let entry of entries) {
let provider = entry.provider;
let collectPromise;
try {
collectPromise = provider[fnProperty].call(provider);
} catch (ex) {
this._recordProviderError(provider.name, "Exception when calling " +
"collect function: " + fnProperty, ex);
continue;
}
if (!collectPromise) {
this._recordProviderError(provider.name, "Does not return a promise " +
"from " + fnProperty + "()");
continue;
}
let promise = collectPromise.then(function onCollected(result) {
if (onCollect) {
try {
onCollect(entry, result);
} catch (ex) {
this._log.warn("onCollect callback threw: " +
CommonUtils.exceptionStr(ex));
}
}
return CommonUtils.laterTickResolvingPromise(result);
});
promises.push([provider.name, promise]);
}
return this._handleCollectionPromises(promises, providerDiagnostic);
},
/**
* Handles promises returned by the collect* functions.
*
* This consumes the data resolved by the promises and returns a new promise
* that will be resolved once all promises have been resolved.
*
* The promise is resolved even if one of the underlying collection
* promises is rejected.
*/
_handleCollectionPromises: function (promises, providerDiagnostic=null) {
return Task.spawn(function waitForPromises() {
for (let [name, promise] of promises) {
if (providerDiagnostic) {
providerDiagnostic(name);
}
try {
yield promise;
this._log.debug("Provider collected successfully: " + name);
} catch (ex) {
this._recordProviderError(name, "Failed to collect", ex);
}
}
throw new Task.Result(this);
}.bind(this));
},
/**
* Record an error that occurred operating on a provider.
*/
_recordProviderError: function (name, msg, ex) {
msg = "Provider error: " + name + ": " + msg;
if (ex) {
msg += ": " + CommonUtils.exceptionStr(ex);
}
this._log.warn(msg);
if (this.onProviderError) {
try {
this.onProviderError(msg);
} catch (callError) {
this._log.warn("Exception when calling onProviderError callback: " +
CommonUtils.exceptionStr(callError));
}
}
},
});