Merge "Remove all 'lock_utils' now that fasteners provides equivalents"

8 files changed, 16 insertions, 508 deletions

diff --git a/doc/source/utils.rst b/doc/source/utils.rst
index 6949ccf..ac0dd5c 100644
--- a/doc/source/utils.rst
+++ b/doc/source/utils.rst
@@ -33,11 +33,6 @@ Kombu
 
 .. automodule:: taskflow.utils.kombu_utils
 
-Locks
-~~~~~
-
-.. automodule:: taskflow.utils.lock_utils
-
 Miscellaneous
 ~~~~~~~~~~~~~
 
diff --git a/taskflow/conductors/base.py b/taskflow/conductors/base.py
index 7a6b8ce..6e46fff 100644
--- a/taskflow/conductors/base.py
+++ b/taskflow/conductors/base.py
@@ -15,11 +15,11 @@
 import abc
 import threading
 
+import fasteners
 import six
 
 from taskflow import engines
 from taskflow import exceptions as excp
-from taskflow.utils import lock_utils
 
 
 @six.add_metaclass(abc.ABCMeta)
@@ -109,13 +109,13 @@ class Conductor(object):
         #                listener factories over the jobboard
         return []
 
-    @lock_utils.locked
+    @fasteners.locked
     def connect(self):
         """Ensures the jobboard is connected (noop if it is already)."""
         if not self._jobboard.connected:
             self._jobboard.connect()
 
-    @lock_utils.locked
+    @fasteners.locked
     def close(self):
         """Closes the contained jobboard, disallowing further use."""
         self._jobboard.close()
diff --git a/taskflow/engines/action_engine/compiler.py b/taskflow/engines/action_engine/compiler.py
index ff86de2..dc6c24e 100644
--- a/taskflow/engines/action_engine/compiler.py
+++ b/taskflow/engines/action_engine/compiler.py
@@ -17,13 +17,14 @@
 import collections
 import threading
 
+import fasteners
+
 from taskflow import exceptions as exc
 from taskflow import flow
 from taskflow import logging
 from taskflow import task
 from taskflow.types import graph as gr
 from taskflow.types import tree as tr
-from taskflow.utils import lock_utils
 from taskflow.utils import misc
 
 LOG = logging.getLogger(__name__)
@@ -423,7 +424,7 @@ class PatternCompiler(object):
                 # Indent it so that it's slightly offset from the above line.
                 LOG.blather("  %s", line)
 
-    @lock_utils.locked
+    @fasteners.locked
     def compile(self):
         """Compiles the contained item into a compiled equivalent."""
         if self._compilation is None:
diff --git a/taskflow/engines/action_engine/engine.py b/taskflow/engines/action_engine/engine.py
index 3dda912..124b8a5 100644
--- a/taskflow/engines/action_engine/engine.py
+++ b/taskflow/engines/action_engine/engine.py
@@ -19,6 +19,7 @@ import contextlib
 import threading
 
 from concurrent import futures
+import fasteners
 import networkx as nx
 from oslo_utils import excutils
 from oslo_utils import strutils
@@ -33,7 +34,6 @@ from taskflow import logging
 from taskflow import states
 from taskflow import storage
 from taskflow.types import failure
-from taskflow.utils import lock_utils
 from taskflow.utils import misc
 
 LOG = logging.getLogger(__name__)
@@ -133,7 +133,7 @@ class ActionEngine(base.Engine):
                                scope_fetcher=_scope_fetcher)
 
     def run(self):
-        with lock_utils.try_lock(self._lock) as was_locked:
+        with fasteners.try_lock(self._lock) as was_locked:
             if not was_locked:
                 raise exc.ExecutionFailure("Engine currently locked, please"
                                            " try again later")
@@ -222,7 +222,7 @@ class ActionEngine(base.Engine):
                                               node.inject,
                                               transient=transient)
 
-    @lock_utils.locked
+    @fasteners.locked
     def validate(self):
         self._check('validate', True, True)
         # At this point we can check to ensure all dependencies are either
@@ -266,7 +266,7 @@ class ActionEngine(base.Engine):
                                               sorted(missing),
                                               cause=last_cause)
 
-    @lock_utils.locked
+    @fasteners.locked
     def prepare(self):
         self._check('prepare', True, False)
         if not self._storage_ensured:
@@ -286,7 +286,7 @@ class ActionEngine(base.Engine):
     def _compiler(self):
         return self._compiler_factory(self._flow)
 
-    @lock_utils.locked
+    @fasteners.locked
     def compile(self):
         if self._compiled:
             return
diff --git a/taskflow/engines/worker_based/protocol.py b/taskflow/engines/worker_based/protocol.py
index 867f536..cbb61eb 100644
--- a/taskflow/engines/worker_based/protocol.py
+++ b/taskflow/engines/worker_based/protocol.py
@@ -19,6 +19,7 @@ import collections
 import threading
 
 from concurrent import futures
+import fasteners
 from oslo_utils import reflection
 from oslo_utils import timeutils
 import six
@@ -28,7 +29,6 @@ from taskflow import exceptions as excp
 from taskflow import logging
 from taskflow.types import failure as ft
 from taskflow.types import timing as tt
-from taskflow.utils import lock_utils
 from taskflow.utils import schema_utils as su
 
 # NOTE(skudriashev): This is protocol states and events, which are not
@@ -336,7 +336,7 @@ class Request(Message):
                         new_state, exc_info=True)
         return moved
 
-    @lock_utils.locked
+    @fasteners.locked
     def transition(self, new_state):
         """Transitions the request to a new state.
 
diff --git a/taskflow/jobs/backends/impl_zookeeper.py b/taskflow/jobs/backends/impl_zookeeper.py
index 246416f..d92c2ba 100644
--- a/taskflow/jobs/backends/impl_zookeeper.py
+++ b/taskflow/jobs/backends/impl_zookeeper.py
@@ -21,6 +21,7 @@ import sys
 import threading
 
 from concurrent import futures
+import fasteners
 from kazoo import exceptions as k_exceptions
 from kazoo.protocol import paths as k_paths
 from kazoo.recipe import watchers
@@ -35,7 +36,6 @@ from taskflow import logging
 from taskflow import states
 from taskflow.types import timing as tt
 from taskflow.utils import kazoo_utils
-from taskflow.utils import lock_utils
 from taskflow.utils import misc
 
 LOG = logging.getLogger(__name__)
@@ -762,7 +762,7 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
     def connected(self):
         return self._connected and self._client.connected
 
-    @lock_utils.locked(lock='_open_close_lock')
+    @fasteners.locked(lock='_open_close_lock')
     def close(self):
         if self._owned:
             LOG.debug("Stopping client")
@@ -776,7 +776,7 @@ class ZookeeperJobBoard(base.NotifyingJobBoard):
         LOG.debug("Stopped & cleared local state")
         self._connected = False
 
-    @lock_utils.locked(lock='_open_close_lock')
+    @fasteners.locked(lock='_open_close_lock')
     def connect(self, timeout=10.0):
 
         def try_clean():
diff --git a/taskflow/tests/unit/test_utils_lock_utils.py b/taskflow/tests/unit/test_utils_lock_utils.py
deleted file mode 100644
index 0c8213e..0000000
--- a/taskflow/tests/unit/test_utils_lock_utils.py
+++ /dev/null
@@ -1,281 +0,0 @@
-# -*- coding: utf-8 -*-
-
-#    Copyright (C) 2014 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 threading
-import time
-
-from taskflow import test
-from taskflow.test import mock
-from taskflow.utils import lock_utils
-from taskflow.utils import misc
-from taskflow.utils import threading_utils
-
-# NOTE(harlowja): Sleep a little so now() can not be the same (which will
-# cause false positives when our overlap detection code runs). If there are
-# real overlaps then they will still exist.
-NAPPY_TIME = 0.05
-
-# We will spend this amount of time doing some "fake" work.
-WORK_TIMES = [(0.01 + x / 100.0) for x in range(0, 5)]
-
-# Try to use a more accurate time for overlap detection (one that should
-# never go backwards and cause false positives during overlap detection...).
-now = misc.find_monotonic(allow_time_time=True)
-
-
-def _find_overlaps(times, start, end):
-    overlaps = 0
-    for (s, e) in times:
-        if s >= start and e <= end:
-            overlaps += 1
-    return overlaps
-
-
-class MultilockTest(test.TestCase):
-    THREAD_COUNT = 20
-
-    def test_empty_error(self):
-        self.assertRaises(ValueError,
-                          lock_utils.MultiLock, [])
-        self.assertRaises(ValueError,
-                          lock_utils.MultiLock, ())
-        self.assertRaises(ValueError,
-                          lock_utils.MultiLock, iter([]))
-
-    def test_creation(self):
-        locks = []
-        for _i in range(0, 10):
-            locks.append(threading.Lock())
-        n_lock = lock_utils.MultiLock(locks)
-        self.assertEqual(0, n_lock.obtained)
-        self.assertEqual(len(locks), len(n_lock))
-
-    def test_acquired(self):
-        lock1 = threading.Lock()
-        lock2 = threading.Lock()
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-        self.assertTrue(n_lock.acquire())
-        try:
-            self.assertTrue(lock1.locked())
-            self.assertTrue(lock2.locked())
-        finally:
-            n_lock.release()
-        self.assertFalse(lock1.locked())
-        self.assertFalse(lock2.locked())
-
-    def test_acquired_context_manager(self):
-        lock1 = threading.Lock()
-        n_lock = lock_utils.MultiLock([lock1])
-        with n_lock as gotten:
-            self.assertTrue(gotten)
-            self.assertTrue(lock1.locked())
-        self.assertFalse(lock1.locked())
-        self.assertEqual(0, n_lock.obtained)
-
-    def test_partial_acquired(self):
-        lock1 = threading.Lock()
-        lock2 = mock.create_autospec(threading.Lock())
-        lock2.acquire.return_value = False
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-        with n_lock as gotten:
-            self.assertFalse(gotten)
-            self.assertTrue(lock1.locked())
-            self.assertEqual(1, n_lock.obtained)
-            self.assertEqual(2, len(n_lock))
-        self.assertEqual(0, n_lock.obtained)
-
-    def test_partial_acquired_failure(self):
-        lock1 = threading.Lock()
-        lock2 = mock.create_autospec(threading.Lock())
-        lock2.acquire.side_effect = RuntimeError("Broke")
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-        self.assertRaises(threading.ThreadError, n_lock.acquire)
-        self.assertEqual(1, n_lock.obtained)
-        n_lock.release()
-
-    def test_release_failure(self):
-        lock1 = threading.Lock()
-        lock2 = mock.create_autospec(threading.Lock())
-        lock2.acquire.return_value = True
-        lock2.release.side_effect = RuntimeError("Broke")
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-        self.assertTrue(n_lock.acquire())
-        self.assertEqual(2, n_lock.obtained)
-        self.assertRaises(threading.ThreadError, n_lock.release)
-        self.assertEqual(2, n_lock.obtained)
-        lock2.release.side_effect = None
-        n_lock.release()
-        self.assertEqual(0, n_lock.obtained)
-
-    def test_release_partial_failure(self):
-        lock1 = threading.Lock()
-        lock2 = mock.create_autospec(threading.Lock())
-        lock2.acquire.return_value = True
-        lock2.release.side_effect = RuntimeError("Broke")
-        lock3 = threading.Lock()
-        n_lock = lock_utils.MultiLock((lock1, lock2, lock3))
-        self.assertTrue(n_lock.acquire())
-        self.assertEqual(3, n_lock.obtained)
-        self.assertRaises(threading.ThreadError, n_lock.release)
-        self.assertEqual(2, n_lock.obtained)
-        lock2.release.side_effect = None
-        n_lock.release()
-        self.assertEqual(0, n_lock.obtained)
-
-    def test_acquired_pass(self):
-        activated = collections.deque()
-        acquires = collections.deque()
-        lock1 = threading.Lock()
-        lock2 = threading.Lock()
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-
-        def critical_section():
-            start = now()
-            time.sleep(NAPPY_TIME)
-            end = now()
-            activated.append((start, end))
-
-        def run():
-            with n_lock as gotten:
-                acquires.append(gotten)
-                critical_section()
-
-        threads = []
-        for _i in range(0, self.THREAD_COUNT):
-            t = threading_utils.daemon_thread(run)
-            threads.append(t)
-            t.start()
-        while threads:
-            t = threads.pop()
-            t.join()
-
-        self.assertEqual(self.THREAD_COUNT, len(acquires))
-        self.assertTrue(all(acquires))
-        for (start, end) in activated:
-            self.assertEqual(1, _find_overlaps(activated, start, end))
-        self.assertFalse(lock1.locked())
-        self.assertFalse(lock2.locked())
-
-    def test_acquired_fail(self):
-        activated = collections.deque()
-        acquires = collections.deque()
-        lock1 = threading.Lock()
-        lock2 = threading.Lock()
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-
-        def run():
-            with n_lock as gotten:
-                acquires.append(gotten)
-                start = now()
-                time.sleep(NAPPY_TIME)
-                end = now()
-                activated.append((start, end))
-
-        def run_fail():
-            try:
-                with n_lock as gotten:
-                    acquires.append(gotten)
-                    raise RuntimeError()
-            except RuntimeError:
-                pass
-
-        threads = []
-        for i in range(0, self.THREAD_COUNT):
-            if i % 2 == 1:
-                target = run_fail
-            else:
-                target = run
-            t = threading_utils.daemon_thread(target)
-            threads.append(t)
-            t.start()
-        while threads:
-            t = threads.pop()
-            t.join()
-
-        self.assertEqual(self.THREAD_COUNT, len(acquires))
-        self.assertTrue(all(acquires))
-        for (start, end) in activated:
-            self.assertEqual(1, _find_overlaps(activated, start, end))
-        self.assertFalse(lock1.locked())
-        self.assertFalse(lock2.locked())
-
-    def test_double_acquire_single(self):
-        activated = collections.deque()
-        acquires = []
-
-        def run():
-            start = now()
-            time.sleep(NAPPY_TIME)
-            end = now()
-            activated.append((start, end))
-
-        lock1 = threading.RLock()
-        lock2 = threading.RLock()
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-        with n_lock as gotten:
-            acquires.append(gotten)
-            run()
-            with n_lock as gotten:
-                acquires.append(gotten)
-                run()
-            run()
-
-        self.assertTrue(all(acquires))
-        self.assertEqual(2, len(acquires))
-        for (start, end) in activated:
-            self.assertEqual(1, _find_overlaps(activated, start, end))
-
-    def test_double_acquire_many(self):
-        activated = collections.deque()
-        acquires = collections.deque()
-        n_lock = lock_utils.MultiLock((threading.RLock(), threading.RLock()))
-
-        def critical_section():
-            start = now()
-            time.sleep(NAPPY_TIME)
-            end = now()
-            activated.append((start, end))
-
-        def run():
-            with n_lock as gotten:
-                acquires.append(gotten)
-                critical_section()
-                with n_lock as gotten:
-                    acquires.append(gotten)
-                    critical_section()
-                critical_section()
-
-        threads = []
-        for i in range(0, self.THREAD_COUNT):
-            t = threading_utils.daemon_thread(run)
-            threads.append(t)
-            t.start()
-        while threads:
-            t = threads.pop()
-            t.join()
-
-        self.assertTrue(all(acquires))
-        self.assertEqual(self.THREAD_COUNT * 2, len(acquires))
-        self.assertEqual(self.THREAD_COUNT * 3, len(activated))
-        for (start, end) in activated:
-            self.assertEqual(1, _find_overlaps(activated, start, end))
-
-    def test_no_acquire_release(self):
-        lock1 = threading.Lock()
-        lock2 = threading.Lock()
-        n_lock = lock_utils.MultiLock((lock1, lock2))
-        self.assertRaises(threading.ThreadError, n_lock.release)
diff --git a/taskflow/utils/lock_utils.py b/taskflow/utils/lock_utils.py
deleted file mode 100644
index 7b1b026..0000000
--- a/taskflow/utils/lock_utils.py
+++ /dev/null
@@ -1,207 +0,0 @@
-# Copyright 2011 OpenStack Foundation.
-# 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.
-
-# This is a modified version of what was in oslo-incubator lockutils.py from
-# commit 5039a610355e5265fb9fbd1f4023e8160750f32e but this one does not depend
-# on oslo.cfg or the very large oslo-incubator oslo logging module (which also
-# pulls in oslo.cfg) and is reduced to only what taskflow currently wants to
-# use from that code.
-
-import contextlib
-import threading
-
-import six
-
-from taskflow import logging
-from taskflow.utils import misc
-
-LOG = logging.getLogger(__name__)
-
-
-@contextlib.contextmanager
-def try_lock(lock):
-    """Attempts to acquire a lock, and auto releases if acquired (on exit)."""
-    # NOTE(harlowja): the keyword argument for 'blocking' does not work
-    # in py2.x and only is fixed in py3.x (this adjustment is documented
-    # and/or debated in http://bugs.python.org/issue10789); so we'll just
-    # stick to the format that works in both (oddly the keyword argument
-    # works in py2.x but only with reentrant locks).
-    was_locked = lock.acquire(False)
-    try:
-        yield was_locked
-    finally:
-        if was_locked:
-            lock.release()
-
-
-def locked(*args, **kwargs):
-    """A locking decorator.
-
-    It will look for a provided attribute (typically a lock or a list
-    of locks) on the first argument of the function decorated (typically this
-    is the 'self' object) and before executing the decorated function it
-    activates the given lock or list of locks as a context manager,
-    automatically releasing that lock on exit.
-
-    NOTE(harlowja): if no attribute name is provided then by default the
-    attribute named '_lock' is looked for (this attribute is expected to be
-    the lock/list of locks object/s) in the instance object this decorator
-    is attached to.
-    """
-
-    def decorator(f):
-        attr_name = kwargs.get('lock', '_lock')
-
-        @six.wraps(f)
-        def wrapper(self, *args, **kwargs):
-            attr_value = getattr(self, attr_name)
-            if isinstance(attr_value, (tuple, list)):
-                lock = MultiLock(attr_value)
-            else:
-                lock = attr_value
-            with lock:
-                return f(self, *args, **kwargs)
-
-        return wrapper
-
-    # This is needed to handle when the decorator has args or the decorator
-    # doesn't have args, python is rather weird here...
-    if kwargs or not args:
-        return decorator
-    else:
-        if len(args) == 1:
-            return decorator(args[0])
-        else:
-            return decorator
-
-
-class MultiLock(object):
-    """A class which attempts to obtain & release many locks at once.
-
-    It is typically useful as a context manager around many locks (instead of
-    having to nest individual lock context managers, which can become pretty
-    awkward looking).
-
-    NOTE(harlowja): The locks that will be obtained will be in the order the
-    locks are given in the constructor, they will be acquired in order and
-    released in reverse order (so ordering matters).
-    """
-
-    def __init__(self, locks):
-        if not isinstance(locks, tuple):
-            locks = tuple(locks)
-        if len(locks) <= 0:
-            raise ValueError("Zero locks requested")
-        self._locks = locks
-        self._local = threading.local()
-
-    @property
-    def _lock_stacks(self):
-        # This is weird, but this is how thread locals work (in that each
-        # thread will need to check if it has already created the attribute and
-        # if not then create it and set it to the thread local variable...)
-        #
-        # This isn't done in the constructor since the constructor is only
-        # activated by one of the many threads that could use this object,
-        # and that means that the attribute will only exist for that one
-        # thread.
-        try:
-            return self._local.stacks
-        except AttributeError:
-            self._local.stacks = []
-            return self._local.stacks
-
-    def __enter__(self):
-        return self.acquire()
-
-    @property
-    def obtained(self):
-        """Returns how many locks were last acquired/obtained."""
-        try:
-            return self._lock_stacks[-1]
-        except IndexError:
-            return 0
-
-    def __len__(self):
-        return len(self._locks)
-
-    def acquire(self):
-        """This will attempt to acquire all the locks given in the constructor.
-
-        If all the locks can not be acquired (and say only X of Y locks could
-        be acquired then this will return false to signify that not all the
-        locks were able to be acquired, you can later use the :attr:`.obtained`
-        property to determine how many were obtained during the last
-        acquisition attempt).
-
-        NOTE(harlowja): When not all locks were acquired it is still required
-        to release since under partial acquisition the acquired locks
-        must still be released. For example if 4 out of 5 locks were acquired
-        this will return false, but the user **must** still release those
-        other 4 to avoid causing locking issues...
-        """
-        gotten = 0
-        for lock in self._locks:
-            try:
-                acked = lock.acquire()
-            except (threading.ThreadError, RuntimeError) as e:
-                # If we have already gotten some set of the desired locks
-                # make sure we track that and ensure that we later release them
-                # instead of losing them.
-                if gotten:
-                    self._lock_stacks.append(gotten)
-                raise threading.ThreadError(
-                    "Unable to acquire lock %s/%s due to '%s'"
-                    % (gotten + 1, len(self._locks), e))
-            else:
-                if not acked:
-                    break
-                else:
-                    gotten += 1
-        if gotten:
-            self._lock_stacks.append(gotten)
-        return gotten == len(self._locks)
-
-    def __exit__(self, type, value, traceback):
-        self.release()
-
-    def release(self):
-        """Releases any past acquired locks (partial or otherwise)."""
-        height = len(self._lock_stacks)
-        if not height:
-            # Raise the same error type as the threading.Lock raises so that
-            # it matches the behavior of the built-in class (it's odd though
-            # that the threading.RLock raises a runtime error on this same
-            # method instead...)
-            raise threading.ThreadError('Release attempted on unlocked lock')
-        # Cleans off one level of the stack (this is done so that if there
-        # are multiple __enter__() and __exit__() pairs active that this will
-        # only remove one level (the last one), and not all levels...
-        for left in misc.countdown_iter(self._lock_stacks[-1]):
-            lock_idx = left - 1
-            lock = self._locks[lock_idx]
-            try:
-                lock.release()
-            except (threading.ThreadError, RuntimeError) as e:
-                # Ensure that we adjust the lock stack under failure so that
-                # if release is attempted again that we do not try to release
-                # the locks we already released...
-                self._lock_stacks[-1] = left
-                raise threading.ThreadError(
-                    "Unable to release lock %s/%s due to '%s'"
-                    % (left, len(self._locks), e))
-        # At the end only clear it off, so that under partial failure we don't
-        # lose any locks...
-        self._lock_stacks.pop()