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import os |
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from threading import Lock |
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import warnings |
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from .mmap_dict import mmap_key, MmapedDict |
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class MutexValue: |
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"""A float protected by a mutex.""" |
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_multiprocess = False |
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def __init__(self, typ, metric_name, name, labelnames, labelvalues, help_text, **kwargs): |
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self._value = 0.0 |
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self._exemplar = None |
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self._lock = Lock() |
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def inc(self, amount): |
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with self._lock: |
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self._value += amount |
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def set(self, value, timestamp=None): |
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with self._lock: |
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self._value = value |
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def set_exemplar(self, exemplar): |
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with self._lock: |
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self._exemplar = exemplar |
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def get(self): |
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with self._lock: |
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return self._value |
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def get_exemplar(self): |
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with self._lock: |
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return self._exemplar |
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def MultiProcessValue(process_identifier=os.getpid): |
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"""Returns a MmapedValue class based on a process_identifier function. |
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The 'process_identifier' function MUST comply with this simple rule: |
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when called in simultaneously running processes it MUST return distinct values. |
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Using a different function than the default 'os.getpid' is at your own risk. |
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""" |
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files = {} |
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values = [] |
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pid = {'value': process_identifier()} |
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lock = Lock() |
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class MmapedValue: |
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"""A float protected by a mutex backed by a per-process mmaped file.""" |
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_multiprocess = True |
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def __init__(self, typ, metric_name, name, labelnames, labelvalues, help_text, multiprocess_mode='', **kwargs): |
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self._params = typ, metric_name, name, labelnames, labelvalues, help_text, multiprocess_mode |
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if 'prometheus_multiproc_dir' in os.environ and 'PROMETHEUS_MULTIPROC_DIR' not in os.environ: |
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os.environ['PROMETHEUS_MULTIPROC_DIR'] = os.environ['prometheus_multiproc_dir'] |
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warnings.warn("prometheus_multiproc_dir variable has been deprecated in favor of the upper case naming PROMETHEUS_MULTIPROC_DIR", DeprecationWarning) |
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with lock: |
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self.__check_for_pid_change() |
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self.__reset() |
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values.append(self) |
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def __reset(self): |
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typ, metric_name, name, labelnames, labelvalues, help_text, multiprocess_mode = self._params |
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if typ == 'gauge': |
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file_prefix = typ + '_' + multiprocess_mode |
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else: |
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file_prefix = typ |
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if file_prefix not in files: |
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filename = os.path.join( |
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os.environ.get('PROMETHEUS_MULTIPROC_DIR'), |
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'{}_{}.db'.format(file_prefix, pid['value'])) |
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files[file_prefix] = MmapedDict(filename) |
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self._file = files[file_prefix] |
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self._key = mmap_key(metric_name, name, labelnames, labelvalues, help_text) |
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self._value, self._timestamp = self._file.read_value(self._key) |
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def __check_for_pid_change(self): |
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actual_pid = process_identifier() |
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if pid['value'] != actual_pid: |
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pid['value'] = actual_pid |
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for f in files.values(): |
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f.close() |
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files.clear() |
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for value in values: |
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value.__reset() |
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def inc(self, amount): |
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with lock: |
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self.__check_for_pid_change() |
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self._value += amount |
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self._timestamp = 0.0 |
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self._file.write_value(self._key, self._value, self._timestamp) |
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def set(self, value, timestamp=None): |
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with lock: |
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self.__check_for_pid_change() |
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self._value = value |
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self._timestamp = timestamp or 0.0 |
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self._file.write_value(self._key, self._value, self._timestamp) |
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def set_exemplar(self, exemplar): |
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return |
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def get(self): |
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with lock: |
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self.__check_for_pid_change() |
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return self._value |
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def get_exemplar(self): |
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return None |
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return MmapedValue |
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def get_value_class(): |
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if 'prometheus_multiproc_dir' in os.environ or 'PROMETHEUS_MULTIPROC_DIR' in os.environ: |
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return MultiProcessValue() |
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else: |
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return MutexValue |
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ValueClass = get_value_class() |
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