File size: 4,369 Bytes
03c4799 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 | from __future__ import unicode_literals
import os
from threading import Lock
import warnings
from .mmap_dict import mmap_key, MmapedDict
class MutexValue(object):
"""A float protected by a mutex."""
_multiprocess = False
def __init__(self, typ, metric_name, name, labelnames, labelvalues, **kwargs):
self._value = 0.0
self._lock = Lock()
def inc(self, amount):
with self._lock:
self._value += amount
def set(self, value):
with self._lock:
self._value = value
def get(self):
with self._lock:
return self._value
def MultiProcessValue(process_identifier=os.getpid):
"""Returns a MmapedValue class based on a process_identifier function.
The 'process_identifier' function MUST comply with this simple rule:
when called in simultaneously running processes it MUST return distinct values.
Using a different function than the default 'os.getpid' is at your own risk.
"""
files = {}
values = []
pid = {'value': process_identifier()}
# Use a single global lock when in multi-processing mode
# as we presume this means there is no threading going on.
# This avoids the need to also have mutexes in __MmapDict.
lock = Lock()
class MmapedValue(object):
"""A float protected by a mutex backed by a per-process mmaped file."""
_multiprocess = True
def __init__(self, typ, metric_name, name, labelnames, labelvalues, multiprocess_mode='', **kwargs):
self._params = typ, metric_name, name, labelnames, labelvalues, multiprocess_mode
# This deprecation warning can go away in a few releases when removing the compatibility
if 'prometheus_multiproc_dir' in os.environ and 'PROMETHEUS_MULTIPROC_DIR' not in os.environ:
os.environ['PROMETHEUS_MULTIPROC_DIR'] = os.environ['prometheus_multiproc_dir']
warnings.warn("prometheus_multiproc_dir variable has been deprecated in favor of the upper case naming PROMETHEUS_MULTIPROC_DIR", DeprecationWarning)
with lock:
self.__check_for_pid_change()
self.__reset()
values.append(self)
def __reset(self):
typ, metric_name, name, labelnames, labelvalues, multiprocess_mode = self._params
if typ == 'gauge':
file_prefix = typ + '_' + multiprocess_mode
else:
file_prefix = typ
if file_prefix not in files:
filename = os.path.join(
os.environ.get('PROMETHEUS_MULTIPROC_DIR'),
'{0}_{1}.db'.format(file_prefix, pid['value']))
files[file_prefix] = MmapedDict(filename)
self._file = files[file_prefix]
self._key = mmap_key(metric_name, name, labelnames, labelvalues)
self._value = self._file.read_value(self._key)
def __check_for_pid_change(self):
actual_pid = process_identifier()
if pid['value'] != actual_pid:
pid['value'] = actual_pid
# There has been a fork(), reset all the values.
for f in files.values():
f.close()
files.clear()
for value in values:
value.__reset()
def inc(self, amount):
with lock:
self.__check_for_pid_change()
self._value += amount
self._file.write_value(self._key, self._value)
def set(self, value):
with lock:
self.__check_for_pid_change()
self._value = value
self._file.write_value(self._key, self._value)
def get(self):
with lock:
self.__check_for_pid_change()
return self._value
return MmapedValue
def get_value_class():
# Should we enable multi-process mode?
# This needs to be chosen before the first metric is constructed,
# and as that may be in some arbitrary library the user/admin has
# no control over we use an environment variable.
if 'prometheus_multiproc_dir' in os.environ or 'PROMETHEUS_MULTIPROC_DIR' in os.environ:
return MultiProcessValue()
else:
return MutexValue
ValueClass = get_value_class()
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