From cd048d8530340d4d0d6a5c5b8cbc88ca0ceea1b9 Mon Sep 17 00:00:00 2001
From: Julien Danjou <julien@danjou.info>
Date: Mon, 20 Mar 2017 14:39:18 +0100
Subject: [PATCH] coordination: remove custom Lock object

There's no need to create and manage a custom lock object as tooz locks
are doing exactly the same thing directly. That simplifies even more
the code.

Change-Id: I85493fbf4195f9dea3ea53cd37a741370d6f00ad
---
 cinder/coordination.py                 | 64 +-------------------------
 cinder/tests/unit/test_coordination.py |  4 --
 cinder/volume/manager.py               |  2 +-
 3 files changed, 3 insertions(+), 67 deletions(-)

diff --git a/cinder/coordination.py b/cinder/coordination.py
index 3e4b97babf2..8c42460996f 100644
--- a/cinder/coordination.py
+++ b/cinder/coordination.py
@@ -27,9 +27,7 @@ import itertools
 from oslo_config import cfg
 from oslo_log import log
 from oslo_utils import timeutils
-import six
 from tooz import coordination
-from tooz import locking
 
 from cinder import exception
 from cinder.i18n import _
@@ -180,65 +178,7 @@ class Coordinator(object):
 COORDINATOR = Coordinator(prefix='cinder-')
 
 
-class Lock(locking.Lock):
-    """Lock with dynamic name.
-
-    :param str lock_name: Lock name.
-    :param dict lock_data: Data for lock name formatting.
-    :param coordinator: Coordinator class to use when creating lock.
-        Defaults to the global coordinator.
-
-    Using it like so::
-
-        with Lock('mylock'):
-           ...
-
-    ensures that only one process at a time will execute code in context.
-    Lock name can be formatted using Python format string syntax::
-
-        Lock('foo-{volume.id}, {'volume': ...,})
-
-    Available field names are keys of lock_data.
-    """
-    def __init__(self, lock_name, lock_data=None, coordinator=None):
-        super(Lock, self).__init__(str(id(self)))
-        lock_data = lock_data or {}
-        self.coordinator = coordinator or COORDINATOR
-        self.blocking = True
-        self.lock = self._prepare_lock(lock_name, lock_data)
-
-    def _prepare_lock(self, lock_name, lock_data):
-        if not isinstance(lock_name, six.string_types):
-            raise ValueError(_('Not a valid string: %s') % lock_name)
-        self._name = lock_name.format(**lock_data)
-        return self.coordinator.get_lock(self._name)
-
-    @property
-    def name(self):
-        return self._name
-
-    def acquire(self, blocking=None):
-        """Attempts to acquire lock.
-
-        :param blocking: If True, blocks until the lock is acquired. If False,
-            returns right away. Otherwise, the value is used as a timeout
-            value and the call returns maximum after this number of seconds.
-        :return: returns true if acquired (false if not)
-        :rtype: bool
-        """
-        blocking = self.blocking if blocking is None else blocking
-        return self.lock.acquire(blocking=blocking)
-
-    def release(self):
-        """Attempts to release lock.
-
-        The behavior of releasing a lock which was not acquired in the first
-        place is undefined.
-        """
-        self.lock.release()
-
-
-def synchronized(lock_name, blocking=True, coordinator=None):
+def synchronized(lock_name, blocking=True, coordinator=COORDINATOR):
     """Synchronization decorator.
 
     :param str lock_name: Lock name.
@@ -284,7 +224,7 @@ def synchronized(lock_name, blocking=True, coordinator=None):
     def _synchronized(f, *a, **k):
         call_args = inspect.getcallargs(f, *a, **k)
         call_args['f_name'] = f.__name__
-        lock = Lock(lock_name, call_args, coordinator)
+        lock = coordinator.get_lock(lock_name.format(**call_args))
         t1 = timeutils.now()
         t2 = None
         try:
diff --git a/cinder/tests/unit/test_coordination.py b/cinder/tests/unit/test_coordination.py
index 9e07e2ad967..dcb8617c5bd 100644
--- a/cinder/tests/unit/test_coordination.py
+++ b/cinder/tests/unit/test_coordination.py
@@ -123,10 +123,6 @@ class CoordinatorTestCase(test.TestCase):
 
 @mock.patch.object(coordination.COORDINATOR, 'get_lock')
 class CoordinationTestCase(test.TestCase):
-    def test_lock(self, get_lock):
-        with coordination.Lock('lock'):
-            self.assertTrue(get_lock.called)
-
     def test_synchronized(self, get_lock):
         @coordination.synchronized('lock-{f_name}-{foo.val}-{bar[val]}')
         def func(foo, bar):
diff --git a/cinder/volume/manager.py b/cinder/volume/manager.py
index 014b334f8e9..c5ddea35fcb 100644
--- a/cinder/volume/manager.py
+++ b/cinder/volume/manager.py
@@ -669,7 +669,7 @@ class VolumeManager(manager.CleanableManager,
             if locked_action is None:
                 _run_flow()
             else:
-                with coordination.Lock(locked_action):
+                with coordination.COORDINATOR.get_lock(locked_action):
                     _run_flow()
         finally:
             try: