gecko-dev/toolkit/components/telemetry/histogram_tools.py
2015-07-02 20:59:36 -04:00

355 lines
13 KiB
Python

# 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/.
import collections
import json
import math
import os
import re
import sys
# histogram_tools.py is used by scripts from a mozilla-central build tree
# and also by outside consumers, such as the telemetry server. We need
# to ensure that importing things works in both contexts. Therefore,
# unconditionally importing things that are local to the build tree, such
# as buildconfig, is a no-no.
try:
import buildconfig
# Need to update sys.path to be able to find usecounters.
sys.path.append(os.path.join(buildconfig.topsrcdir, 'dom/base/'))
except ImportError:
# Must be in an out-of-tree usage scenario. Trust that whoever is
# running this script knows we need the usecounters module and has
# ensured it's in our sys.path.
pass
from collections import OrderedDict
def table_dispatch(kind, table, body):
"""Call body with table[kind] if it exists. Raise an error otherwise."""
if kind in table:
return body(table[kind])
else:
raise BaseException, "don't know how to handle a histogram of kind %s" % kind
class DefinitionException(BaseException):
pass
def check_numeric_limits(dmin, dmax, n_buckets):
if type(dmin) != int:
raise DefinitionException, "minimum is not a number"
if type(dmax) != int:
raise DefinitionException, "maximum is not a number"
if type(n_buckets) != int:
raise DefinitionException, "number of buckets is not a number"
def linear_buckets(dmin, dmax, n_buckets):
check_numeric_limits(dmin, dmax, n_buckets)
ret_array = [0] * n_buckets
dmin = float(dmin)
dmax = float(dmax)
for i in range(1, n_buckets):
linear_range = (dmin * (n_buckets - 1 - i) + dmax * (i - 1)) / (n_buckets - 2)
ret_array[i] = int(linear_range + 0.5)
return ret_array
def exponential_buckets(dmin, dmax, n_buckets):
check_numeric_limits(dmin, dmax, n_buckets)
log_max = math.log(dmax);
bucket_index = 2;
ret_array = [0] * n_buckets
current = dmin
ret_array[1] = current
for bucket_index in range(2, n_buckets):
log_current = math.log(current)
log_ratio = (log_max - log_current) / (n_buckets - bucket_index)
log_next = log_current + log_ratio
next_value = int(math.floor(math.exp(log_next) + 0.5))
if next_value > current:
current = next_value
else:
current = current + 1
ret_array[bucket_index] = current
return ret_array
always_allowed_keys = ['kind', 'description', 'cpp_guard', 'expires_in_version',
'alert_emails', 'keyed', 'releaseChannelCollection']
class Histogram:
"""A class for representing a histogram definition."""
def __init__(self, name, definition):
"""Initialize a histogram named name with the given definition.
definition is a dict-like object that must contain at least the keys:
- 'kind': The kind of histogram. Must be one of 'boolean', 'flag',
'count', 'enumerated', 'linear', or 'exponential'.
- 'description': A textual description of the histogram.
The key 'cpp_guard' is optional; if present, it denotes a preprocessor
symbol that should guard C/C++ definitions associated with the histogram."""
self.check_name(name)
self.verify_attributes(name, definition)
self._name = name
self._description = definition['description']
self._kind = definition['kind']
self._cpp_guard = definition.get('cpp_guard')
self._keyed = definition.get('keyed', False)
self._extended_statistics_ok = definition.get('extended_statistics_ok', False)
self._expiration = definition.get('expires_in_version')
self.compute_bucket_parameters(definition)
table = { 'boolean': 'BOOLEAN',
'flag': 'FLAG',
'count': 'COUNT',
'enumerated': 'LINEAR',
'linear': 'LINEAR',
'exponential': 'EXPONENTIAL' }
table_dispatch(self.kind(), table,
lambda k: self._set_nsITelemetry_kind(k))
datasets = { 'opt-in': 'DATASET_RELEASE_CHANNEL_OPTIN',
'opt-out': 'DATASET_RELEASE_CHANNEL_OPTOUT' }
value = definition.get('releaseChannelCollection', 'opt-in')
if not value in datasets:
raise DefinitionException, "unknown release channel collection policy for " + name
self._dataset = "nsITelemetry::" + datasets[value]
def name(self):
"""Return the name of the histogram."""
return self._name
def description(self):
"""Return the description of the histogram."""
return self._description
def kind(self):
"""Return the kind of the histogram.
Will be one of 'boolean', 'flag', 'count', 'enumerated', 'linear', or 'exponential'."""
return self._kind
def expiration(self):
"""Return the expiration version of the histogram."""
return self._expiration
def nsITelemetry_kind(self):
"""Return the nsITelemetry constant corresponding to the kind of
the histogram."""
return self._nsITelemetry_kind
def _set_nsITelemetry_kind(self, kind):
self._nsITelemetry_kind = "nsITelemetry::HISTOGRAM_%s" % kind
def low(self):
"""Return the lower bound of the histogram. May be a string."""
return self._low
def high(self):
"""Return the high bound of the histogram. May be a string."""
return self._high
def n_buckets(self):
"""Return the number of buckets in the histogram. May be a string."""
return self._n_buckets
def cpp_guard(self):
"""Return the preprocessor symbol that should guard C/C++ definitions
associated with the histogram. Returns None if no guarding is necessary."""
return self._cpp_guard
def keyed(self):
"""Returns True if this a keyed histogram, false otherwise."""
return self._keyed
def dataset(self):
"""Returns the dataset this histogram belongs into."""
return self._dataset
def extended_statistics_ok(self):
"""Return True if gathering extended statistics for this histogram
is enabled."""
return self._extended_statistics_ok
def ranges(self):
"""Return an array of lower bounds for each bucket in the histogram."""
table = { 'boolean': linear_buckets,
'flag': linear_buckets,
'count': linear_buckets,
'enumerated': linear_buckets,
'linear': linear_buckets,
'exponential': exponential_buckets }
return table_dispatch(self.kind(), table,
lambda p: p(self.low(), self.high(), self.n_buckets()))
def compute_bucket_parameters(self, definition):
table = {
'boolean': Histogram.boolean_flag_bucket_parameters,
'flag': Histogram.boolean_flag_bucket_parameters,
'count': Histogram.boolean_flag_bucket_parameters,
'enumerated': Histogram.enumerated_bucket_parameters,
'linear': Histogram.linear_bucket_parameters,
'exponential': Histogram.exponential_bucket_parameters
}
table_dispatch(self.kind(), table,
lambda p: self.set_bucket_parameters(*p(definition)))
def verify_attributes(self, name, definition):
global always_allowed_keys
general_keys = always_allowed_keys + ['low', 'high', 'n_buckets']
table = {
'boolean': always_allowed_keys,
'flag': always_allowed_keys,
'count': always_allowed_keys,
'enumerated': always_allowed_keys + ['n_values'],
'linear': general_keys,
'exponential': general_keys + ['extended_statistics_ok']
}
table_dispatch(definition['kind'], table,
lambda allowed_keys: Histogram.check_keys(name, definition, allowed_keys))
Histogram.check_expiration(name, definition)
def check_name(self, name):
if '#' in name:
raise ValueError, '"#" not permitted for %s' % (name)
@staticmethod
def check_expiration(name, definition):
expiration = definition.get('expires_in_version')
if not expiration:
return
if re.match(r'^[1-9][0-9]*$', expiration):
expiration = expiration + ".0a1"
elif re.match(r'^[1-9][0-9]*\.0$', expiration):
expiration = expiration + "a1"
definition['expires_in_version'] = expiration
@staticmethod
def check_keys(name, definition, allowed_keys):
for key in definition.iterkeys():
if key not in allowed_keys:
raise KeyError, '%s not permitted for %s' % (key, name)
def set_bucket_parameters(self, low, high, n_buckets):
def try_to_coerce_to_number(v):
try:
return eval(v, {})
except:
return v
self._low = try_to_coerce_to_number(low)
self._high = try_to_coerce_to_number(high)
self._n_buckets = try_to_coerce_to_number(n_buckets)
@staticmethod
def boolean_flag_bucket_parameters(definition):
return (1, 2, 3)
@staticmethod
def linear_bucket_parameters(definition):
return (definition.get('low', 1),
definition['high'],
definition['n_buckets'])
@staticmethod
def enumerated_bucket_parameters(definition):
n_values = definition['n_values']
return (1, n_values, "%s+1" % n_values)
@staticmethod
def exponential_bucket_parameters(definition):
return (definition.get('low', 1),
definition['high'],
definition['n_buckets'])
# We support generating histograms from multiple different input files, not
# just Histograms.json. For each file's basename, we have a specific
# routine to parse that file, and return a dictionary mapping histogram
# names to histogram parameters.
def from_Histograms_json(filename):
with open(filename, 'r') as f:
try:
histograms = json.load(f, object_pairs_hook=OrderedDict)
except ValueError, e:
raise BaseException, "error parsing histograms in %s: %s" % (filename, e.message)
return histograms
def from_UseCounters_conf(filename):
return usecounters.generate_histograms(filename)
def from_nsDeprecatedOperationList(filename):
operation_regex = re.compile('^DEPRECATED_OPERATION\\(([^)]+)\\)')
histograms = collections.OrderedDict()
with open(filename, 'r') as f:
for line in f:
match = operation_regex.search(line)
if not match:
continue
op = match.group(1)
def add_counter(context):
name = 'USE_COUNTER_DEPRECATED_%s_%s' % (op, context.upper())
histograms[name] = {
'expires_in_version': 'never',
'kind': 'boolean',
'description': 'Whether a %s used %s' % (context, op)
}
add_counter('document')
add_counter('page')
return histograms
FILENAME_PARSERS = {
'Histograms.json': from_Histograms_json,
'nsDeprecatedOperationList.h': from_nsDeprecatedOperationList,
}
# Similarly to the dance above with buildconfig, usecounters may not be
# available, so handle that gracefully.
try:
import usecounters
FILENAME_PARSERS['UseCounters.conf'] = from_UseCounters_conf
except ImportError:
pass
def from_files(filenames):
"""Return an iterator that provides a sequence of Histograms for
the histograms defined in filenames.
"""
all_histograms = OrderedDict()
for filename in filenames:
parser = FILENAME_PARSERS[os.path.basename(filename)]
histograms = parser(filename)
# OrderedDicts are important, because then the iteration order over
# the parsed histograms is stable, which makes the insertion into
# all_histograms stable, which makes ordering in generated files
# stable, which makes builds more deterministic.
if not isinstance(histograms, OrderedDict):
raise BaseException, "histogram parser didn't provide an OrderedDict"
for (name, definition) in histograms.iteritems():
if all_histograms.has_key(name):
raise DefinitionException, "duplicate histogram name %s" % name
all_histograms[name] = definition
# We require that all USE_COUNTER_* histograms be defined in a contiguous
# block.
use_counter_indices = filter(lambda x: x[1].startswith("USE_COUNTER_"),
enumerate(all_histograms.iterkeys()));
if use_counter_indices:
lower_bound = use_counter_indices[0][0]
upper_bound = use_counter_indices[-1][0]
n_counters = upper_bound - lower_bound + 1
if n_counters != len(use_counter_indices):
raise DefinitionException, "use counter histograms must be defined in a contiguous block"
for (name, definition) in all_histograms.iteritems():
yield Histogram(name, definition)