/usr/lib/python2.7/dist-packages/taskflow/utils/threading_utils.py is in python-taskflow 2.3.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 | # -*- coding: utf-8 -*-
# Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import collections
import multiprocessing
import threading
import six
from six.moves import _thread
from taskflow.utils import misc
def is_alive(thread):
"""Helper to determine if a thread is alive (handles none safely)."""
if not thread:
return False
return thread.is_alive()
def get_ident():
"""Return the 'thread identifier' of the current thread."""
return _thread.get_ident()
def get_optimal_thread_count(default=2):
"""Try to guess optimal thread count for current system."""
try:
return multiprocessing.cpu_count() + 1
except NotImplementedError:
# NOTE(harlowja): apparently may raise so in this case we will
# just setup two threads since it's hard to know what else we
# should do in this situation.
return default
def daemon_thread(target, *args, **kwargs):
"""Makes a daemon thread that calls the given target when started."""
thread = threading.Thread(target=target, args=args, kwargs=kwargs)
# NOTE(skudriashev): When the main thread is terminated unexpectedly
# and thread is still alive - it will prevent main thread from exiting
# unless the daemon property is set to True.
thread.daemon = True
return thread
# Container for thread creator + associated callbacks.
_ThreadBuilder = collections.namedtuple('_ThreadBuilder',
['thread_factory',
'before_start', 'after_start',
'before_join', 'after_join'])
_ThreadBuilder.fields = tuple([
'thread_factory',
'before_start',
'after_start',
'before_join',
'after_join',
])
def no_op(*args, **kwargs):
"""Function that does nothing."""
class ThreadBundle(object):
"""A group/bundle of threads that start/stop together."""
def __init__(self):
self._threads = []
self._lock = threading.Lock()
def bind(self, thread_factory,
before_start=None, after_start=None,
before_join=None, after_join=None):
"""Adds a thread (to-be) into this bundle (with given callbacks).
NOTE(harlowja): callbacks provided should not attempt to call
mutating methods (:meth:`.stop`, :meth:`.start`,
:meth:`.bind` ...) on this object as that will result
in dead-lock since the lock on this object is not
meant to be (and is not) reentrant...
"""
if before_start is None:
before_start = no_op
if after_start is None:
after_start = no_op
if before_join is None:
before_join = no_op
if after_join is None:
after_join = no_op
builder = _ThreadBuilder(thread_factory,
before_start, after_start,
before_join, after_join)
for attr_name in builder.fields:
cb = getattr(builder, attr_name)
if not six.callable(cb):
raise ValueError("Provided callback for argument"
" '%s' must be callable" % attr_name)
with self._lock:
self._threads.append([
builder,
# The built thread.
None,
# Whether the built thread was started (and should have
# ran or still be running).
False,
])
def start(self):
"""Creates & starts all associated threads (that are not running)."""
count = 0
with self._lock:
it = enumerate(self._threads)
for i, (builder, thread, started) in it:
if thread and started:
continue
if not thread:
self._threads[i][1] = thread = builder.thread_factory()
builder.before_start(thread)
thread.start()
count += 1
try:
builder.after_start(thread)
finally:
# Just incase the 'after_start' callback blows up make sure
# we always set this...
self._threads[i][2] = started = True
return count
def stop(self):
"""Stops & joins all associated threads (that have been started)."""
count = 0
with self._lock:
it = misc.reverse_enumerate(self._threads)
for i, (builder, thread, started) in it:
if not thread or not started:
continue
builder.before_join(thread)
thread.join()
count += 1
try:
builder.after_join(thread)
finally:
# Just incase the 'after_join' callback blows up make sure
# we always set/reset these...
self._threads[i][1] = thread = None
self._threads[i][2] = started = False
return count
def __len__(self):
"""Returns how many threads (to-be) are in this bundle."""
return len(self._threads)
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