root / lib / locking.py @ a01225a6
History | View | Annotate | Download (52.5 kB)
1 | 162c1c1f | Guido Trotter | #
|
---|---|---|---|
2 | 162c1c1f | Guido Trotter | #
|
3 | 162c1c1f | Guido Trotter | |
4 | 7f93570a | Iustin Pop | # Copyright (C) 2006, 2007, 2008, 2009, 2010 Google Inc.
|
5 | 162c1c1f | Guido Trotter | #
|
6 | 162c1c1f | Guido Trotter | # This program is free software; you can redistribute it and/or modify
|
7 | 162c1c1f | Guido Trotter | # it under the terms of the GNU General Public License as published by
|
8 | 162c1c1f | Guido Trotter | # the Free Software Foundation; either version 2 of the License, or
|
9 | 162c1c1f | Guido Trotter | # (at your option) any later version.
|
10 | 162c1c1f | Guido Trotter | #
|
11 | 162c1c1f | Guido Trotter | # This program is distributed in the hope that it will be useful, but
|
12 | 162c1c1f | Guido Trotter | # WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 | 162c1c1f | Guido Trotter | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
14 | 162c1c1f | Guido Trotter | # General Public License for more details.
|
15 | 162c1c1f | Guido Trotter | #
|
16 | 162c1c1f | Guido Trotter | # You should have received a copy of the GNU General Public License
|
17 | 162c1c1f | Guido Trotter | # along with this program; if not, write to the Free Software
|
18 | 162c1c1f | Guido Trotter | # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
19 | 162c1c1f | Guido Trotter | # 02110-1301, USA.
|
20 | 162c1c1f | Guido Trotter | |
21 | 162c1c1f | Guido Trotter | """Module implementing the Ganeti locking code."""
|
22 | 162c1c1f | Guido Trotter | |
23 | c70d2d9b | Iustin Pop | # pylint: disable-msg=W0212
|
24 | c70d2d9b | Iustin Pop | |
25 | c70d2d9b | Iustin Pop | # W0212 since e.g. LockSet methods use (a lot) the internals of
|
26 | c70d2d9b | Iustin Pop | # SharedLock
|
27 | 162c1c1f | Guido Trotter | |
28 | d76167a5 | Michael Hanselmann | import os |
29 | d76167a5 | Michael Hanselmann | import select |
30 | 162c1c1f | Guido Trotter | import threading |
31 | d76167a5 | Michael Hanselmann | import errno |
32 | 19b9ba9a | Michael Hanselmann | import weakref |
33 | 19b9ba9a | Michael Hanselmann | import logging |
34 | 887c7aa6 | Michael Hanselmann | import heapq |
35 | 24d16f76 | Michael Hanselmann | import operator |
36 | e4e35357 | Michael Hanselmann | import itertools |
37 | 84e344d4 | Michael Hanselmann | |
38 | a95fd5d7 | Guido Trotter | from ganeti import errors |
39 | 7ee7c0c7 | Guido Trotter | from ganeti import utils |
40 | cea881e5 | Michael Hanselmann | from ganeti import compat |
41 | 24d16f76 | Michael Hanselmann | from ganeti import query |
42 | 162c1c1f | Guido Trotter | |
43 | 162c1c1f | Guido Trotter | |
44 | c31825f7 | Michael Hanselmann | _EXCLUSIVE_TEXT = "exclusive"
|
45 | c31825f7 | Michael Hanselmann | _SHARED_TEXT = "shared"
|
46 | 24d16f76 | Michael Hanselmann | _DELETED_TEXT = "deleted"
|
47 | c31825f7 | Michael Hanselmann | |
48 | 887c7aa6 | Michael Hanselmann | _DEFAULT_PRIORITY = 0
|
49 | 887c7aa6 | Michael Hanselmann | |
50 | c31825f7 | Michael Hanselmann | |
51 | dbb11e8b | Guido Trotter | def ssynchronized(mylock, shared=0): |
52 | 42a999d1 | Guido Trotter | """Shared Synchronization decorator.
|
53 | 42a999d1 | Guido Trotter |
|
54 | 42a999d1 | Guido Trotter | Calls the function holding the given lock, either in exclusive or shared
|
55 | 42a999d1 | Guido Trotter | mode. It requires the passed lock to be a SharedLock (or support its
|
56 | 42a999d1 | Guido Trotter | semantics).
|
57 | 42a999d1 | Guido Trotter |
|
58 | dbb11e8b | Guido Trotter | @type mylock: lockable object or string
|
59 | dbb11e8b | Guido Trotter | @param mylock: lock to acquire or class member name of the lock to acquire
|
60 | dbb11e8b | Guido Trotter |
|
61 | 42a999d1 | Guido Trotter | """
|
62 | 42a999d1 | Guido Trotter | def wrap(fn): |
63 | 42a999d1 | Guido Trotter | def sync_function(*args, **kwargs): |
64 | dbb11e8b | Guido Trotter | if isinstance(mylock, basestring): |
65 | dbb11e8b | Guido Trotter | assert args, "cannot ssynchronize on non-class method: self not found" |
66 | dbb11e8b | Guido Trotter | # args[0] is "self"
|
67 | dbb11e8b | Guido Trotter | lock = getattr(args[0], mylock) |
68 | dbb11e8b | Guido Trotter | else:
|
69 | dbb11e8b | Guido Trotter | lock = mylock |
70 | 42a999d1 | Guido Trotter | lock.acquire(shared=shared) |
71 | 42a999d1 | Guido Trotter | try:
|
72 | 42a999d1 | Guido Trotter | return fn(*args, **kwargs)
|
73 | 42a999d1 | Guido Trotter | finally:
|
74 | 42a999d1 | Guido Trotter | lock.release() |
75 | 42a999d1 | Guido Trotter | return sync_function
|
76 | 42a999d1 | Guido Trotter | return wrap
|
77 | 42a999d1 | Guido Trotter | |
78 | 42a999d1 | Guido Trotter | |
79 | 34cb5617 | Guido Trotter | class _SingleNotifyPipeConditionWaiter(object): |
80 | 34cb5617 | Guido Trotter | """Helper class for SingleNotifyPipeCondition
|
81 | d76167a5 | Michael Hanselmann |
|
82 | d76167a5 | Michael Hanselmann | """
|
83 | d76167a5 | Michael Hanselmann | __slots__ = [ |
84 | d76167a5 | Michael Hanselmann | "_fd",
|
85 | d76167a5 | Michael Hanselmann | "_poller",
|
86 | d76167a5 | Michael Hanselmann | ] |
87 | d76167a5 | Michael Hanselmann | |
88 | 34cb5617 | Guido Trotter | def __init__(self, poller, fd): |
89 | 34cb5617 | Guido Trotter | """Constructor for _SingleNotifyPipeConditionWaiter
|
90 | d76167a5 | Michael Hanselmann |
|
91 | d76167a5 | Michael Hanselmann | @type poller: select.poll
|
92 | d76167a5 | Michael Hanselmann | @param poller: Poller object
|
93 | d76167a5 | Michael Hanselmann | @type fd: int
|
94 | d76167a5 | Michael Hanselmann | @param fd: File descriptor to wait for
|
95 | d76167a5 | Michael Hanselmann |
|
96 | d76167a5 | Michael Hanselmann | """
|
97 | d76167a5 | Michael Hanselmann | object.__init__(self) |
98 | d76167a5 | Michael Hanselmann | self._poller = poller
|
99 | d76167a5 | Michael Hanselmann | self._fd = fd
|
100 | d76167a5 | Michael Hanselmann | |
101 | d76167a5 | Michael Hanselmann | def __call__(self, timeout): |
102 | d76167a5 | Michael Hanselmann | """Wait for something to happen on the pipe.
|
103 | d76167a5 | Michael Hanselmann |
|
104 | d76167a5 | Michael Hanselmann | @type timeout: float or None
|
105 | d76167a5 | Michael Hanselmann | @param timeout: Timeout for waiting (can be None)
|
106 | d76167a5 | Michael Hanselmann |
|
107 | d76167a5 | Michael Hanselmann | """
|
108 | 557838c1 | René Nussbaumer | running_timeout = utils.RunningTimeout(timeout, True)
|
109 | f4e673fb | Michael Hanselmann | |
110 | f4e673fb | Michael Hanselmann | while True: |
111 | f4e673fb | Michael Hanselmann | remaining_time = running_timeout.Remaining() |
112 | f4e673fb | Michael Hanselmann | |
113 | b44b0141 | Michael Hanselmann | if remaining_time is not None: |
114 | b44b0141 | Michael Hanselmann | if remaining_time < 0.0: |
115 | b44b0141 | Michael Hanselmann | break
|
116 | d76167a5 | Michael Hanselmann | |
117 | 413b7472 | Michael Hanselmann | # Our calculation uses seconds, poll() wants milliseconds
|
118 | b44b0141 | Michael Hanselmann | remaining_time *= 1000
|
119 | d76167a5 | Michael Hanselmann | |
120 | d76167a5 | Michael Hanselmann | try:
|
121 | d76167a5 | Michael Hanselmann | result = self._poller.poll(remaining_time)
|
122 | d76167a5 | Michael Hanselmann | except EnvironmentError, err: |
123 | d76167a5 | Michael Hanselmann | if err.errno != errno.EINTR:
|
124 | d76167a5 | Michael Hanselmann | raise
|
125 | d76167a5 | Michael Hanselmann | result = None
|
126 | d76167a5 | Michael Hanselmann | |
127 | d76167a5 | Michael Hanselmann | # Check whether we were notified
|
128 | d76167a5 | Michael Hanselmann | if result and result[0][0] == self._fd: |
129 | d76167a5 | Michael Hanselmann | break
|
130 | d76167a5 | Michael Hanselmann | |
131 | d76167a5 | Michael Hanselmann | |
132 | 2419060d | Guido Trotter | class _BaseCondition(object): |
133 | 2419060d | Guido Trotter | """Base class containing common code for conditions.
|
134 | 2419060d | Guido Trotter |
|
135 | 2419060d | Guido Trotter | Some of this code is taken from python's threading module.
|
136 | 2419060d | Guido Trotter |
|
137 | 2419060d | Guido Trotter | """
|
138 | 2419060d | Guido Trotter | __slots__ = [ |
139 | 2419060d | Guido Trotter | "_lock",
|
140 | 2419060d | Guido Trotter | "acquire",
|
141 | 2419060d | Guido Trotter | "release",
|
142 | 7f890059 | Guido Trotter | "_is_owned",
|
143 | 7f890059 | Guido Trotter | "_acquire_restore",
|
144 | 7f890059 | Guido Trotter | "_release_save",
|
145 | 2419060d | Guido Trotter | ] |
146 | 2419060d | Guido Trotter | |
147 | 2419060d | Guido Trotter | def __init__(self, lock): |
148 | 2419060d | Guido Trotter | """Constructor for _BaseCondition.
|
149 | 2419060d | Guido Trotter |
|
150 | 69b99987 | Michael Hanselmann | @type lock: threading.Lock
|
151 | 2419060d | Guido Trotter | @param lock: condition base lock
|
152 | 2419060d | Guido Trotter |
|
153 | 2419060d | Guido Trotter | """
|
154 | 2419060d | Guido Trotter | object.__init__(self) |
155 | 2419060d | Guido Trotter | |
156 | 7f890059 | Guido Trotter | try:
|
157 | 7f890059 | Guido Trotter | self._release_save = lock._release_save
|
158 | 7f890059 | Guido Trotter | except AttributeError: |
159 | 7f890059 | Guido Trotter | self._release_save = self._base_release_save |
160 | 7f890059 | Guido Trotter | try:
|
161 | 7f890059 | Guido Trotter | self._acquire_restore = lock._acquire_restore
|
162 | 7f890059 | Guido Trotter | except AttributeError: |
163 | 7f890059 | Guido Trotter | self._acquire_restore = self._base_acquire_restore |
164 | 7f890059 | Guido Trotter | try:
|
165 | 7f890059 | Guido Trotter | self._is_owned = lock._is_owned
|
166 | 7f890059 | Guido Trotter | except AttributeError: |
167 | 7f890059 | Guido Trotter | self._is_owned = self._base_is_owned |
168 | 2419060d | Guido Trotter | |
169 | 2419060d | Guido Trotter | self._lock = lock
|
170 | 2419060d | Guido Trotter | |
171 | 2419060d | Guido Trotter | # Export the lock's acquire() and release() methods
|
172 | 2419060d | Guido Trotter | self.acquire = lock.acquire
|
173 | 2419060d | Guido Trotter | self.release = lock.release
|
174 | 2419060d | Guido Trotter | |
175 | 7f890059 | Guido Trotter | def _base_is_owned(self): |
176 | 2419060d | Guido Trotter | """Check whether lock is owned by current thread.
|
177 | 2419060d | Guido Trotter |
|
178 | 2419060d | Guido Trotter | """
|
179 | 2419060d | Guido Trotter | if self._lock.acquire(0): |
180 | 2419060d | Guido Trotter | self._lock.release()
|
181 | 2419060d | Guido Trotter | return False |
182 | 2419060d | Guido Trotter | return True |
183 | 2419060d | Guido Trotter | |
184 | 7f890059 | Guido Trotter | def _base_release_save(self): |
185 | 7f890059 | Guido Trotter | self._lock.release()
|
186 | 7f890059 | Guido Trotter | |
187 | 7f890059 | Guido Trotter | def _base_acquire_restore(self, _): |
188 | 7f890059 | Guido Trotter | self._lock.acquire()
|
189 | 7f890059 | Guido Trotter | |
190 | 2419060d | Guido Trotter | def _check_owned(self): |
191 | 2419060d | Guido Trotter | """Raise an exception if the current thread doesn't own the lock.
|
192 | 2419060d | Guido Trotter |
|
193 | 2419060d | Guido Trotter | """
|
194 | 2419060d | Guido Trotter | if not self._is_owned(): |
195 | 2419060d | Guido Trotter | raise RuntimeError("cannot work with un-aquired lock") |
196 | 2419060d | Guido Trotter | |
197 | 2419060d | Guido Trotter | |
198 | 34cb5617 | Guido Trotter | class SingleNotifyPipeCondition(_BaseCondition): |
199 | 34cb5617 | Guido Trotter | """Condition which can only be notified once.
|
200 | d76167a5 | Michael Hanselmann |
|
201 | 34cb5617 | Guido Trotter | This condition class uses pipes and poll, internally, to be able to wait for
|
202 | 34cb5617 | Guido Trotter | notification with a timeout, without resorting to polling. It is almost
|
203 | 34cb5617 | Guido Trotter | compatible with Python's threading.Condition, with the following differences:
|
204 | 34cb5617 | Guido Trotter | - notifyAll can only be called once, and no wait can happen after that
|
205 | 34cb5617 | Guido Trotter | - notify is not supported, only notifyAll
|
206 | d76167a5 | Michael Hanselmann |
|
207 | d76167a5 | Michael Hanselmann | """
|
208 | 34cb5617 | Guido Trotter | |
209 | 154b9580 | Balazs Lecz | __slots__ = [ |
210 | d76167a5 | Michael Hanselmann | "_poller",
|
211 | d76167a5 | Michael Hanselmann | "_read_fd",
|
212 | d76167a5 | Michael Hanselmann | "_write_fd",
|
213 | d76167a5 | Michael Hanselmann | "_nwaiters",
|
214 | 34cb5617 | Guido Trotter | "_notified",
|
215 | d76167a5 | Michael Hanselmann | ] |
216 | d76167a5 | Michael Hanselmann | |
217 | 34cb5617 | Guido Trotter | _waiter_class = _SingleNotifyPipeConditionWaiter |
218 | d76167a5 | Michael Hanselmann | |
219 | 34cb5617 | Guido Trotter | def __init__(self, lock): |
220 | 34cb5617 | Guido Trotter | """Constructor for SingleNotifyPipeCondition
|
221 | d76167a5 | Michael Hanselmann |
|
222 | d76167a5 | Michael Hanselmann | """
|
223 | 34cb5617 | Guido Trotter | _BaseCondition.__init__(self, lock)
|
224 | d76167a5 | Michael Hanselmann | self._nwaiters = 0 |
225 | 34cb5617 | Guido Trotter | self._notified = False |
226 | 34cb5617 | Guido Trotter | self._read_fd = None |
227 | 34cb5617 | Guido Trotter | self._write_fd = None |
228 | 34cb5617 | Guido Trotter | self._poller = None |
229 | d76167a5 | Michael Hanselmann | |
230 | 34cb5617 | Guido Trotter | def _check_unnotified(self): |
231 | 69b99987 | Michael Hanselmann | """Throws an exception if already notified.
|
232 | 69b99987 | Michael Hanselmann |
|
233 | 69b99987 | Michael Hanselmann | """
|
234 | 34cb5617 | Guido Trotter | if self._notified: |
235 | 34cb5617 | Guido Trotter | raise RuntimeError("cannot use already notified condition") |
236 | d76167a5 | Michael Hanselmann | |
237 | 34cb5617 | Guido Trotter | def _Cleanup(self): |
238 | 34cb5617 | Guido Trotter | """Cleanup open file descriptors, if any.
|
239 | d76167a5 | Michael Hanselmann |
|
240 | d76167a5 | Michael Hanselmann | """
|
241 | 34cb5617 | Guido Trotter | if self._read_fd is not None: |
242 | 34cb5617 | Guido Trotter | os.close(self._read_fd)
|
243 | 34cb5617 | Guido Trotter | self._read_fd = None |
244 | d76167a5 | Michael Hanselmann | |
245 | 34cb5617 | Guido Trotter | if self._write_fd is not None: |
246 | 34cb5617 | Guido Trotter | os.close(self._write_fd)
|
247 | 34cb5617 | Guido Trotter | self._write_fd = None |
248 | 34cb5617 | Guido Trotter | self._poller = None |
249 | d76167a5 | Michael Hanselmann | |
250 | 83f2d5f6 | Michael Hanselmann | def wait(self, timeout): |
251 | 34cb5617 | Guido Trotter | """Wait for a notification.
|
252 | d76167a5 | Michael Hanselmann |
|
253 | 34cb5617 | Guido Trotter | @type timeout: float or None
|
254 | 34cb5617 | Guido Trotter | @param timeout: Waiting timeout (can be None)
|
255 | d76167a5 | Michael Hanselmann |
|
256 | d76167a5 | Michael Hanselmann | """
|
257 | 34cb5617 | Guido Trotter | self._check_owned()
|
258 | 34cb5617 | Guido Trotter | self._check_unnotified()
|
259 | d76167a5 | Michael Hanselmann | |
260 | 34cb5617 | Guido Trotter | self._nwaiters += 1 |
261 | 34cb5617 | Guido Trotter | try:
|
262 | 34cb5617 | Guido Trotter | if self._poller is None: |
263 | 34cb5617 | Guido Trotter | (self._read_fd, self._write_fd) = os.pipe() |
264 | 34cb5617 | Guido Trotter | self._poller = select.poll()
|
265 | 34cb5617 | Guido Trotter | self._poller.register(self._read_fd, select.POLLHUP) |
266 | d76167a5 | Michael Hanselmann | |
267 | 34cb5617 | Guido Trotter | wait_fn = self._waiter_class(self._poller, self._read_fd) |
268 | 7f890059 | Guido Trotter | state = self._release_save()
|
269 | 34cb5617 | Guido Trotter | try:
|
270 | 34cb5617 | Guido Trotter | # Wait for notification
|
271 | 34cb5617 | Guido Trotter | wait_fn(timeout) |
272 | 34cb5617 | Guido Trotter | finally:
|
273 | 34cb5617 | Guido Trotter | # Re-acquire lock
|
274 | 7f890059 | Guido Trotter | self._acquire_restore(state)
|
275 | 34cb5617 | Guido Trotter | finally:
|
276 | 34cb5617 | Guido Trotter | self._nwaiters -= 1 |
277 | 34cb5617 | Guido Trotter | if self._nwaiters == 0: |
278 | 34cb5617 | Guido Trotter | self._Cleanup()
|
279 | d76167a5 | Michael Hanselmann | |
280 | 7260cfbe | Iustin Pop | def notifyAll(self): # pylint: disable-msg=C0103 |
281 | d76167a5 | Michael Hanselmann | """Close the writing side of the pipe to notify all waiters.
|
282 | d76167a5 | Michael Hanselmann |
|
283 | d76167a5 | Michael Hanselmann | """
|
284 | 34cb5617 | Guido Trotter | self._check_owned()
|
285 | 34cb5617 | Guido Trotter | self._check_unnotified()
|
286 | 34cb5617 | Guido Trotter | self._notified = True |
287 | d76167a5 | Michael Hanselmann | if self._write_fd is not None: |
288 | d76167a5 | Michael Hanselmann | os.close(self._write_fd)
|
289 | d76167a5 | Michael Hanselmann | self._write_fd = None |
290 | d76167a5 | Michael Hanselmann | |
291 | d76167a5 | Michael Hanselmann | |
292 | 34cb5617 | Guido Trotter | class PipeCondition(_BaseCondition): |
293 | 48dabc6a | Michael Hanselmann | """Group-only non-polling condition with counters.
|
294 | 48dabc6a | Michael Hanselmann |
|
295 | 48dabc6a | Michael Hanselmann | This condition class uses pipes and poll, internally, to be able to wait for
|
296 | 48dabc6a | Michael Hanselmann | notification with a timeout, without resorting to polling. It is almost
|
297 | 48dabc6a | Michael Hanselmann | compatible with Python's threading.Condition, but only supports notifyAll and
|
298 | 48dabc6a | Michael Hanselmann | non-recursive locks. As an additional features it's able to report whether
|
299 | 48dabc6a | Michael Hanselmann | there are any waiting threads.
|
300 | 48dabc6a | Michael Hanselmann |
|
301 | 48dabc6a | Michael Hanselmann | """
|
302 | 154b9580 | Balazs Lecz | __slots__ = [ |
303 | c31825f7 | Michael Hanselmann | "_waiters",
|
304 | 34cb5617 | Guido Trotter | "_single_condition",
|
305 | 48dabc6a | Michael Hanselmann | ] |
306 | 48dabc6a | Michael Hanselmann | |
307 | 34cb5617 | Guido Trotter | _single_condition_class = SingleNotifyPipeCondition |
308 | 48dabc6a | Michael Hanselmann | |
309 | 48dabc6a | Michael Hanselmann | def __init__(self, lock): |
310 | 48dabc6a | Michael Hanselmann | """Initializes this class.
|
311 | 48dabc6a | Michael Hanselmann |
|
312 | 48dabc6a | Michael Hanselmann | """
|
313 | 2419060d | Guido Trotter | _BaseCondition.__init__(self, lock)
|
314 | c31825f7 | Michael Hanselmann | self._waiters = set() |
315 | 34cb5617 | Guido Trotter | self._single_condition = self._single_condition_class(self._lock) |
316 | 48dabc6a | Michael Hanselmann | |
317 | 83f2d5f6 | Michael Hanselmann | def wait(self, timeout): |
318 | 48dabc6a | Michael Hanselmann | """Wait for a notification.
|
319 | 48dabc6a | Michael Hanselmann |
|
320 | 48dabc6a | Michael Hanselmann | @type timeout: float or None
|
321 | 48dabc6a | Michael Hanselmann | @param timeout: Waiting timeout (can be None)
|
322 | 48dabc6a | Michael Hanselmann |
|
323 | 48dabc6a | Michael Hanselmann | """
|
324 | 48dabc6a | Michael Hanselmann | self._check_owned()
|
325 | 48dabc6a | Michael Hanselmann | |
326 | 48dabc6a | Michael Hanselmann | # Keep local reference to the pipe. It could be replaced by another thread
|
327 | 48dabc6a | Michael Hanselmann | # notifying while we're waiting.
|
328 | c31825f7 | Michael Hanselmann | cond = self._single_condition
|
329 | 48dabc6a | Michael Hanselmann | |
330 | c31825f7 | Michael Hanselmann | self._waiters.add(threading.currentThread())
|
331 | 48dabc6a | Michael Hanselmann | try:
|
332 | c31825f7 | Michael Hanselmann | cond.wait(timeout) |
333 | 48dabc6a | Michael Hanselmann | finally:
|
334 | c31825f7 | Michael Hanselmann | self._check_owned()
|
335 | c31825f7 | Michael Hanselmann | self._waiters.remove(threading.currentThread())
|
336 | 48dabc6a | Michael Hanselmann | |
337 | 7260cfbe | Iustin Pop | def notifyAll(self): # pylint: disable-msg=C0103 |
338 | 48dabc6a | Michael Hanselmann | """Notify all currently waiting threads.
|
339 | 48dabc6a | Michael Hanselmann |
|
340 | 48dabc6a | Michael Hanselmann | """
|
341 | 48dabc6a | Michael Hanselmann | self._check_owned()
|
342 | 34cb5617 | Guido Trotter | self._single_condition.notifyAll()
|
343 | 34cb5617 | Guido Trotter | self._single_condition = self._single_condition_class(self._lock) |
344 | 48dabc6a | Michael Hanselmann | |
345 | c31825f7 | Michael Hanselmann | def get_waiting(self): |
346 | c31825f7 | Michael Hanselmann | """Returns a list of all waiting threads.
|
347 | c31825f7 | Michael Hanselmann |
|
348 | c31825f7 | Michael Hanselmann | """
|
349 | c31825f7 | Michael Hanselmann | self._check_owned()
|
350 | c31825f7 | Michael Hanselmann | |
351 | c31825f7 | Michael Hanselmann | return self._waiters |
352 | c31825f7 | Michael Hanselmann | |
353 | 48dabc6a | Michael Hanselmann | def has_waiting(self): |
354 | 48dabc6a | Michael Hanselmann | """Returns whether there are active waiters.
|
355 | 48dabc6a | Michael Hanselmann |
|
356 | 48dabc6a | Michael Hanselmann | """
|
357 | 48dabc6a | Michael Hanselmann | self._check_owned()
|
358 | 48dabc6a | Michael Hanselmann | |
359 | c31825f7 | Michael Hanselmann | return bool(self._waiters) |
360 | 48dabc6a | Michael Hanselmann | |
361 | 48dabc6a | Michael Hanselmann | |
362 | 887c7aa6 | Michael Hanselmann | class _PipeConditionWithMode(PipeCondition): |
363 | 887c7aa6 | Michael Hanselmann | __slots__ = [ |
364 | 887c7aa6 | Michael Hanselmann | "shared",
|
365 | 887c7aa6 | Michael Hanselmann | ] |
366 | 887c7aa6 | Michael Hanselmann | |
367 | 887c7aa6 | Michael Hanselmann | def __init__(self, lock, shared): |
368 | 887c7aa6 | Michael Hanselmann | """Initializes this class.
|
369 | 887c7aa6 | Michael Hanselmann |
|
370 | 887c7aa6 | Michael Hanselmann | """
|
371 | 887c7aa6 | Michael Hanselmann | self.shared = shared
|
372 | 887c7aa6 | Michael Hanselmann | PipeCondition.__init__(self, lock)
|
373 | 887c7aa6 | Michael Hanselmann | |
374 | 887c7aa6 | Michael Hanselmann | |
375 | 84e344d4 | Michael Hanselmann | class SharedLock(object): |
376 | 162c1c1f | Guido Trotter | """Implements a shared lock.
|
377 | 162c1c1f | Guido Trotter |
|
378 | 05ad571c | Michael Hanselmann | Multiple threads can acquire the lock in a shared way by calling
|
379 | 05ad571c | Michael Hanselmann | C{acquire(shared=1)}. In order to acquire the lock in an exclusive way
|
380 | 05ad571c | Michael Hanselmann | threads can call C{acquire(shared=0)}.
|
381 | 162c1c1f | Guido Trotter |
|
382 | 887c7aa6 | Michael Hanselmann | Notes on data structures: C{__pending} contains a priority queue (heapq) of
|
383 | 887c7aa6 | Michael Hanselmann | all pending acquires: C{[(priority1: prioqueue1), (priority2: prioqueue2),
|
384 | 887c7aa6 | Michael Hanselmann | ...]}. Each per-priority queue contains a normal in-order list of conditions
|
385 | 887c7aa6 | Michael Hanselmann | to be notified when the lock can be acquired. Shared locks are grouped
|
386 | 887c7aa6 | Michael Hanselmann | together by priority and the condition for them is stored in
|
387 | 887c7aa6 | Michael Hanselmann | C{__pending_shared} if it already exists. C{__pending_by_prio} keeps
|
388 | 887c7aa6 | Michael Hanselmann | references for the per-priority queues indexed by priority for faster access.
|
389 | 162c1c1f | Guido Trotter |
|
390 | 7f93570a | Iustin Pop | @type name: string
|
391 | 7f93570a | Iustin Pop | @ivar name: the name of the lock
|
392 | 7f93570a | Iustin Pop |
|
393 | 162c1c1f | Guido Trotter | """
|
394 | 84e344d4 | Michael Hanselmann | __slots__ = [ |
395 | 19b9ba9a | Michael Hanselmann | "__weakref__",
|
396 | 84e344d4 | Michael Hanselmann | "__deleted",
|
397 | 84e344d4 | Michael Hanselmann | "__exc",
|
398 | 84e344d4 | Michael Hanselmann | "__lock",
|
399 | 84e344d4 | Michael Hanselmann | "__pending",
|
400 | 887c7aa6 | Michael Hanselmann | "__pending_by_prio",
|
401 | 887c7aa6 | Michael Hanselmann | "__pending_shared",
|
402 | 84e344d4 | Michael Hanselmann | "__shr",
|
403 | 7f93570a | Iustin Pop | "name",
|
404 | 84e344d4 | Michael Hanselmann | ] |
405 | 84e344d4 | Michael Hanselmann | |
406 | 887c7aa6 | Michael Hanselmann | __condition_class = _PipeConditionWithMode |
407 | 84e344d4 | Michael Hanselmann | |
408 | 19b9ba9a | Michael Hanselmann | def __init__(self, name, monitor=None): |
409 | 84e344d4 | Michael Hanselmann | """Construct a new SharedLock.
|
410 | 84e344d4 | Michael Hanselmann |
|
411 | 7f93570a | Iustin Pop | @param name: the name of the lock
|
412 | 19b9ba9a | Michael Hanselmann | @type monitor: L{LockMonitor}
|
413 | 19b9ba9a | Michael Hanselmann | @param monitor: Lock monitor with which to register
|
414 | 7f93570a | Iustin Pop |
|
415 | 84e344d4 | Michael Hanselmann | """
|
416 | 84e344d4 | Michael Hanselmann | object.__init__(self) |
417 | 84e344d4 | Michael Hanselmann | |
418 | 7f93570a | Iustin Pop | self.name = name
|
419 | 7f93570a | Iustin Pop | |
420 | 84e344d4 | Michael Hanselmann | # Internal lock
|
421 | 162c1c1f | Guido Trotter | self.__lock = threading.Lock()
|
422 | 162c1c1f | Guido Trotter | |
423 | 84e344d4 | Michael Hanselmann | # Queue containing waiting acquires
|
424 | 84e344d4 | Michael Hanselmann | self.__pending = []
|
425 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio = {}
|
426 | 887c7aa6 | Michael Hanselmann | self.__pending_shared = {}
|
427 | 84e344d4 | Michael Hanselmann | |
428 | 84e344d4 | Michael Hanselmann | # Current lock holders
|
429 | 162c1c1f | Guido Trotter | self.__shr = set() |
430 | 162c1c1f | Guido Trotter | self.__exc = None |
431 | 162c1c1f | Guido Trotter | |
432 | a95fd5d7 | Guido Trotter | # is this lock in the deleted state?
|
433 | a95fd5d7 | Guido Trotter | self.__deleted = False |
434 | a95fd5d7 | Guido Trotter | |
435 | 19b9ba9a | Michael Hanselmann | # Register with lock monitor
|
436 | 19b9ba9a | Michael Hanselmann | if monitor:
|
437 | 19b9ba9a | Michael Hanselmann | monitor.RegisterLock(self)
|
438 | 19b9ba9a | Michael Hanselmann | |
439 | 24d16f76 | Michael Hanselmann | def GetInfo(self, requested): |
440 | 19b9ba9a | Michael Hanselmann | """Retrieves information for querying locks.
|
441 | 19b9ba9a | Michael Hanselmann |
|
442 | 24d16f76 | Michael Hanselmann | @type requested: set
|
443 | 24d16f76 | Michael Hanselmann | @param requested: Requested information, see C{query.LQ_*}
|
444 | 19b9ba9a | Michael Hanselmann |
|
445 | 19b9ba9a | Michael Hanselmann | """
|
446 | 19b9ba9a | Michael Hanselmann | self.__lock.acquire()
|
447 | 19b9ba9a | Michael Hanselmann | try:
|
448 | 19b9ba9a | Michael Hanselmann | # Note: to avoid unintentional race conditions, no references to
|
449 | 19b9ba9a | Michael Hanselmann | # modifiable objects should be returned unless they were created in this
|
450 | 19b9ba9a | Michael Hanselmann | # function.
|
451 | 24d16f76 | Michael Hanselmann | mode = None
|
452 | 24d16f76 | Michael Hanselmann | owner_names = None
|
453 | 24d16f76 | Michael Hanselmann | |
454 | 24d16f76 | Michael Hanselmann | if query.LQ_MODE in requested: |
455 | 24d16f76 | Michael Hanselmann | if self.__deleted: |
456 | 24d16f76 | Michael Hanselmann | mode = _DELETED_TEXT |
457 | 24d16f76 | Michael Hanselmann | assert not (self.__exc or self.__shr) |
458 | 24d16f76 | Michael Hanselmann | elif self.__exc: |
459 | 24d16f76 | Michael Hanselmann | mode = _EXCLUSIVE_TEXT |
460 | 24d16f76 | Michael Hanselmann | elif self.__shr: |
461 | 24d16f76 | Michael Hanselmann | mode = _SHARED_TEXT |
462 | 24d16f76 | Michael Hanselmann | |
463 | 24d16f76 | Michael Hanselmann | # Current owner(s) are wanted
|
464 | 24d16f76 | Michael Hanselmann | if query.LQ_OWNER in requested: |
465 | 24d16f76 | Michael Hanselmann | if self.__exc: |
466 | 24d16f76 | Michael Hanselmann | owner = [self.__exc]
|
467 | 19b9ba9a | Michael Hanselmann | else:
|
468 | 24d16f76 | Michael Hanselmann | owner = self.__shr
|
469 | 24d16f76 | Michael Hanselmann | |
470 | 24d16f76 | Michael Hanselmann | if owner:
|
471 | 24d16f76 | Michael Hanselmann | assert not self.__deleted |
472 | 24d16f76 | Michael Hanselmann | owner_names = [i.getName() for i in owner] |
473 | 19b9ba9a | Michael Hanselmann | |
474 | 24d16f76 | Michael Hanselmann | # Pending acquires are wanted
|
475 | 24d16f76 | Michael Hanselmann | if query.LQ_PENDING in requested: |
476 | 24d16f76 | Michael Hanselmann | pending = [] |
477 | 24d16f76 | Michael Hanselmann | |
478 | 24d16f76 | Michael Hanselmann | # Sorting instead of copying and using heaq functions for simplicity
|
479 | 24d16f76 | Michael Hanselmann | for (_, prioqueue) in sorted(self.__pending): |
480 | 24d16f76 | Michael Hanselmann | for cond in prioqueue: |
481 | 24d16f76 | Michael Hanselmann | if cond.shared:
|
482 | 24d16f76 | Michael Hanselmann | pendmode = _SHARED_TEXT |
483 | 24d16f76 | Michael Hanselmann | else:
|
484 | 24d16f76 | Michael Hanselmann | pendmode = _EXCLUSIVE_TEXT |
485 | 24d16f76 | Michael Hanselmann | |
486 | 24d16f76 | Michael Hanselmann | # List of names will be sorted in L{query._GetLockPending}
|
487 | 24d16f76 | Michael Hanselmann | pending.append((pendmode, [i.getName() |
488 | 24d16f76 | Michael Hanselmann | for i in cond.get_waiting()])) |
489 | 24d16f76 | Michael Hanselmann | else:
|
490 | 24d16f76 | Michael Hanselmann | pending = None
|
491 | 24d16f76 | Michael Hanselmann | |
492 | 24d16f76 | Michael Hanselmann | return (self.name, mode, owner_names, pending) |
493 | 19b9ba9a | Michael Hanselmann | finally:
|
494 | 19b9ba9a | Michael Hanselmann | self.__lock.release()
|
495 | 19b9ba9a | Michael Hanselmann | |
496 | 84e344d4 | Michael Hanselmann | def __check_deleted(self): |
497 | 84e344d4 | Michael Hanselmann | """Raises an exception if the lock has been deleted.
|
498 | 84e344d4 | Michael Hanselmann |
|
499 | 84e344d4 | Michael Hanselmann | """
|
500 | 84e344d4 | Michael Hanselmann | if self.__deleted: |
501 | 7f93570a | Iustin Pop | raise errors.LockError("Deleted lock %s" % self.name) |
502 | 84e344d4 | Michael Hanselmann | |
503 | 162c1c1f | Guido Trotter | def __is_sharer(self): |
504 | 84e344d4 | Michael Hanselmann | """Is the current thread sharing the lock at this time?
|
505 | 84e344d4 | Michael Hanselmann |
|
506 | 84e344d4 | Michael Hanselmann | """
|
507 | 162c1c1f | Guido Trotter | return threading.currentThread() in self.__shr |
508 | 162c1c1f | Guido Trotter | |
509 | 162c1c1f | Guido Trotter | def __is_exclusive(self): |
510 | 84e344d4 | Michael Hanselmann | """Is the current thread holding the lock exclusively at this time?
|
511 | 84e344d4 | Michael Hanselmann |
|
512 | 84e344d4 | Michael Hanselmann | """
|
513 | 162c1c1f | Guido Trotter | return threading.currentThread() == self.__exc |
514 | 162c1c1f | Guido Trotter | |
515 | 162c1c1f | Guido Trotter | def __is_owned(self, shared=-1): |
516 | 162c1c1f | Guido Trotter | """Is the current thread somehow owning the lock at this time?
|
517 | 162c1c1f | Guido Trotter |
|
518 | 162c1c1f | Guido Trotter | This is a private version of the function, which presumes you're holding
|
519 | 162c1c1f | Guido Trotter | the internal lock.
|
520 | 162c1c1f | Guido Trotter |
|
521 | 162c1c1f | Guido Trotter | """
|
522 | 162c1c1f | Guido Trotter | if shared < 0: |
523 | 162c1c1f | Guido Trotter | return self.__is_sharer() or self.__is_exclusive() |
524 | 162c1c1f | Guido Trotter | elif shared:
|
525 | 162c1c1f | Guido Trotter | return self.__is_sharer() |
526 | 162c1c1f | Guido Trotter | else:
|
527 | 162c1c1f | Guido Trotter | return self.__is_exclusive() |
528 | 162c1c1f | Guido Trotter | |
529 | 162c1c1f | Guido Trotter | def _is_owned(self, shared=-1): |
530 | 162c1c1f | Guido Trotter | """Is the current thread somehow owning the lock at this time?
|
531 | 162c1c1f | Guido Trotter |
|
532 | c41eea6e | Iustin Pop | @param shared:
|
533 | c41eea6e | Iustin Pop | - < 0: check for any type of ownership (default)
|
534 | c41eea6e | Iustin Pop | - 0: check for exclusive ownership
|
535 | c41eea6e | Iustin Pop | - > 0: check for shared ownership
|
536 | 162c1c1f | Guido Trotter |
|
537 | 162c1c1f | Guido Trotter | """
|
538 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
539 | 162c1c1f | Guido Trotter | try:
|
540 | 84e344d4 | Michael Hanselmann | return self.__is_owned(shared=shared) |
541 | 162c1c1f | Guido Trotter | finally:
|
542 | 162c1c1f | Guido Trotter | self.__lock.release()
|
543 | 162c1c1f | Guido Trotter | |
544 | 84e344d4 | Michael Hanselmann | def _count_pending(self): |
545 | 84e344d4 | Michael Hanselmann | """Returns the number of pending acquires.
|
546 | a95fd5d7 | Guido Trotter |
|
547 | 84e344d4 | Michael Hanselmann | @rtype: int
|
548 | a95fd5d7 | Guido Trotter |
|
549 | a95fd5d7 | Guido Trotter | """
|
550 | 84e344d4 | Michael Hanselmann | self.__lock.acquire()
|
551 | 84e344d4 | Michael Hanselmann | try:
|
552 | 887c7aa6 | Michael Hanselmann | return sum(len(prioqueue) for (_, prioqueue) in self.__pending) |
553 | 887c7aa6 | Michael Hanselmann | finally:
|
554 | 887c7aa6 | Michael Hanselmann | self.__lock.release()
|
555 | 887c7aa6 | Michael Hanselmann | |
556 | 887c7aa6 | Michael Hanselmann | def _check_empty(self): |
557 | 887c7aa6 | Michael Hanselmann | """Checks whether there are any pending acquires.
|
558 | 887c7aa6 | Michael Hanselmann |
|
559 | 887c7aa6 | Michael Hanselmann | @rtype: bool
|
560 | 887c7aa6 | Michael Hanselmann |
|
561 | 887c7aa6 | Michael Hanselmann | """
|
562 | 887c7aa6 | Michael Hanselmann | self.__lock.acquire()
|
563 | 887c7aa6 | Michael Hanselmann | try:
|
564 | 887c7aa6 | Michael Hanselmann | # Order is important: __find_first_pending_queue modifies __pending
|
565 | 113359fe | Michael Hanselmann | (_, prioqueue) = self.__find_first_pending_queue()
|
566 | 113359fe | Michael Hanselmann | |
567 | 113359fe | Michael Hanselmann | return not (prioqueue or |
568 | 887c7aa6 | Michael Hanselmann | self.__pending or |
569 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio or |
570 | 887c7aa6 | Michael Hanselmann | self.__pending_shared)
|
571 | 84e344d4 | Michael Hanselmann | finally:
|
572 | 84e344d4 | Michael Hanselmann | self.__lock.release()
|
573 | a95fd5d7 | Guido Trotter | |
574 | 84e344d4 | Michael Hanselmann | def __do_acquire(self, shared): |
575 | 84e344d4 | Michael Hanselmann | """Actually acquire the lock.
|
576 | 84e344d4 | Michael Hanselmann |
|
577 | 84e344d4 | Michael Hanselmann | """
|
578 | 84e344d4 | Michael Hanselmann | if shared:
|
579 | 84e344d4 | Michael Hanselmann | self.__shr.add(threading.currentThread())
|
580 | 84e344d4 | Michael Hanselmann | else:
|
581 | 84e344d4 | Michael Hanselmann | self.__exc = threading.currentThread()
|
582 | a95fd5d7 | Guido Trotter | |
583 | 84e344d4 | Michael Hanselmann | def __can_acquire(self, shared): |
584 | 84e344d4 | Michael Hanselmann | """Determine whether lock can be acquired.
|
585 | a95fd5d7 | Guido Trotter |
|
586 | a95fd5d7 | Guido Trotter | """
|
587 | 84e344d4 | Michael Hanselmann | if shared:
|
588 | 84e344d4 | Michael Hanselmann | return self.__exc is None |
589 | 84e344d4 | Michael Hanselmann | else:
|
590 | 84e344d4 | Michael Hanselmann | return len(self.__shr) == 0 and self.__exc is None |
591 | a95fd5d7 | Guido Trotter | |
592 | 887c7aa6 | Michael Hanselmann | def __find_first_pending_queue(self): |
593 | 887c7aa6 | Michael Hanselmann | """Tries to find the topmost queued entry with pending acquires.
|
594 | 887c7aa6 | Michael Hanselmann |
|
595 | 887c7aa6 | Michael Hanselmann | Removes empty entries while going through the list.
|
596 | 887c7aa6 | Michael Hanselmann |
|
597 | 887c7aa6 | Michael Hanselmann | """
|
598 | 887c7aa6 | Michael Hanselmann | while self.__pending: |
599 | 887c7aa6 | Michael Hanselmann | (priority, prioqueue) = self.__pending[0] |
600 | 887c7aa6 | Michael Hanselmann | |
601 | 887c7aa6 | Michael Hanselmann | if prioqueue:
|
602 | 113359fe | Michael Hanselmann | return (priority, prioqueue)
|
603 | 887c7aa6 | Michael Hanselmann | |
604 | 113359fe | Michael Hanselmann | # Remove empty queue
|
605 | 113359fe | Michael Hanselmann | heapq.heappop(self.__pending)
|
606 | 113359fe | Michael Hanselmann | del self.__pending_by_prio[priority] |
607 | 113359fe | Michael Hanselmann | assert priority not in self.__pending_shared |
608 | 113359fe | Michael Hanselmann | |
609 | 113359fe | Michael Hanselmann | return (None, None) |
610 | 887c7aa6 | Michael Hanselmann | |
611 | 84e344d4 | Michael Hanselmann | def __is_on_top(self, cond): |
612 | 84e344d4 | Michael Hanselmann | """Checks whether the passed condition is on top of the queue.
|
613 | a95fd5d7 | Guido Trotter |
|
614 | 84e344d4 | Michael Hanselmann | The caller must make sure the queue isn't empty.
|
615 | a95fd5d7 | Guido Trotter |
|
616 | 84e344d4 | Michael Hanselmann | """
|
617 | 113359fe | Michael Hanselmann | (_, prioqueue) = self.__find_first_pending_queue()
|
618 | 113359fe | Michael Hanselmann | |
619 | 113359fe | Michael Hanselmann | return cond == prioqueue[0] |
620 | 4d686df8 | Guido Trotter | |
621 | 887c7aa6 | Michael Hanselmann | def __acquire_unlocked(self, shared, timeout, priority): |
622 | 84e344d4 | Michael Hanselmann | """Acquire a shared lock.
|
623 | 9216a9f7 | Michael Hanselmann |
|
624 | 84e344d4 | Michael Hanselmann | @param shared: whether to acquire in shared mode; by default an
|
625 | 84e344d4 | Michael Hanselmann | exclusive lock will be acquired
|
626 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
627 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
628 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
629 | 9216a9f7 | Michael Hanselmann |
|
630 | 9216a9f7 | Michael Hanselmann | """
|
631 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
632 | 9216a9f7 | Michael Hanselmann | |
633 | 84e344d4 | Michael Hanselmann | # We cannot acquire the lock if we already have it
|
634 | 7f93570a | Iustin Pop | assert not self.__is_owned(), ("double acquire() on a non-recursive lock" |
635 | 7f93570a | Iustin Pop | " %s" % self.name) |
636 | 84e344d4 | Michael Hanselmann | |
637 | 887c7aa6 | Michael Hanselmann | # Remove empty entries from queue
|
638 | 887c7aa6 | Michael Hanselmann | self.__find_first_pending_queue()
|
639 | 887c7aa6 | Michael Hanselmann | |
640 | 84e344d4 | Michael Hanselmann | # Check whether someone else holds the lock or there are pending acquires.
|
641 | 84e344d4 | Michael Hanselmann | if not self.__pending and self.__can_acquire(shared): |
642 | 84e344d4 | Michael Hanselmann | # Apparently not, can acquire lock directly.
|
643 | 84e344d4 | Michael Hanselmann | self.__do_acquire(shared)
|
644 | 84e344d4 | Michael Hanselmann | return True |
645 | 9216a9f7 | Michael Hanselmann | |
646 | 887c7aa6 | Michael Hanselmann | prioqueue = self.__pending_by_prio.get(priority, None) |
647 | 9216a9f7 | Michael Hanselmann | |
648 | 887c7aa6 | Michael Hanselmann | if shared:
|
649 | 887c7aa6 | Michael Hanselmann | # Try to re-use condition for shared acquire
|
650 | 887c7aa6 | Michael Hanselmann | wait_condition = self.__pending_shared.get(priority, None) |
651 | 887c7aa6 | Michael Hanselmann | assert (wait_condition is None or |
652 | 887c7aa6 | Michael Hanselmann | (wait_condition.shared and wait_condition in prioqueue)) |
653 | 84e344d4 | Michael Hanselmann | else:
|
654 | 887c7aa6 | Michael Hanselmann | wait_condition = None
|
655 | 887c7aa6 | Michael Hanselmann | |
656 | 887c7aa6 | Michael Hanselmann | if wait_condition is None: |
657 | 887c7aa6 | Michael Hanselmann | if prioqueue is None: |
658 | 887c7aa6 | Michael Hanselmann | assert priority not in self.__pending_by_prio |
659 | 887c7aa6 | Michael Hanselmann | |
660 | 887c7aa6 | Michael Hanselmann | prioqueue = [] |
661 | 887c7aa6 | Michael Hanselmann | heapq.heappush(self.__pending, (priority, prioqueue))
|
662 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio[priority] = prioqueue
|
663 | 887c7aa6 | Michael Hanselmann | |
664 | 887c7aa6 | Michael Hanselmann | wait_condition = self.__condition_class(self.__lock, shared) |
665 | 887c7aa6 | Michael Hanselmann | prioqueue.append(wait_condition) |
666 | 887c7aa6 | Michael Hanselmann | |
667 | 887c7aa6 | Michael Hanselmann | if shared:
|
668 | 887c7aa6 | Michael Hanselmann | # Keep reference for further shared acquires on same priority. This is
|
669 | 887c7aa6 | Michael Hanselmann | # better than trying to find it in the list of pending acquires.
|
670 | 887c7aa6 | Michael Hanselmann | assert priority not in self.__pending_shared |
671 | 887c7aa6 | Michael Hanselmann | self.__pending_shared[priority] = wait_condition
|
672 | 84e344d4 | Michael Hanselmann | |
673 | 84e344d4 | Michael Hanselmann | try:
|
674 | 84e344d4 | Michael Hanselmann | # Wait until we become the topmost acquire in the queue or the timeout
|
675 | 84e344d4 | Michael Hanselmann | # expires.
|
676 | 887c7aa6 | Michael Hanselmann | # TODO: Decrease timeout with spurious notifications
|
677 | 84e344d4 | Michael Hanselmann | while not (self.__is_on_top(wait_condition) and |
678 | 84e344d4 | Michael Hanselmann | self.__can_acquire(shared)):
|
679 | 84e344d4 | Michael Hanselmann | # Wait for notification
|
680 | 84e344d4 | Michael Hanselmann | wait_condition.wait(timeout) |
681 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
682 | 84e344d4 | Michael Hanselmann | |
683 | 84e344d4 | Michael Hanselmann | # A lot of code assumes blocking acquires always succeed. Loop
|
684 | 84e344d4 | Michael Hanselmann | # internally for that case.
|
685 | 84e344d4 | Michael Hanselmann | if timeout is not None: |
686 | 84e344d4 | Michael Hanselmann | break
|
687 | 84e344d4 | Michael Hanselmann | |
688 | 84e344d4 | Michael Hanselmann | if self.__is_on_top(wait_condition) and self.__can_acquire(shared): |
689 | 84e344d4 | Michael Hanselmann | self.__do_acquire(shared)
|
690 | 84e344d4 | Michael Hanselmann | return True |
691 | 9216a9f7 | Michael Hanselmann | finally:
|
692 | 84e344d4 | Michael Hanselmann | # Remove condition from queue if there are no more waiters
|
693 | 887c7aa6 | Michael Hanselmann | if not wait_condition.has_waiting(): |
694 | 887c7aa6 | Michael Hanselmann | prioqueue.remove(wait_condition) |
695 | 887c7aa6 | Michael Hanselmann | if wait_condition.shared:
|
696 | 113359fe | Michael Hanselmann | # Remove from list of shared acquires if it wasn't while releasing
|
697 | 113359fe | Michael Hanselmann | # (e.g. on lock deletion)
|
698 | 113359fe | Michael Hanselmann | self.__pending_shared.pop(priority, None) |
699 | 9216a9f7 | Michael Hanselmann | |
700 | 84e344d4 | Michael Hanselmann | return False |
701 | 9216a9f7 | Michael Hanselmann | |
702 | 7100c2fa | Michael Hanselmann | def acquire(self, shared=0, timeout=None, priority=None, |
703 | 887c7aa6 | Michael Hanselmann | test_notify=None):
|
704 | 162c1c1f | Guido Trotter | """Acquire a shared lock.
|
705 | 162c1c1f | Guido Trotter |
|
706 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
707 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default an
|
708 | c41eea6e | Iustin Pop | exclusive lock will be acquired
|
709 | 84e344d4 | Michael Hanselmann | @type timeout: float
|
710 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
711 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
712 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
713 | 008b92fa | Michael Hanselmann | @type test_notify: callable or None
|
714 | 008b92fa | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
715 | 162c1c1f | Guido Trotter |
|
716 | 162c1c1f | Guido Trotter | """
|
717 | 7100c2fa | Michael Hanselmann | if priority is None: |
718 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
719 | 7100c2fa | Michael Hanselmann | |
720 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
721 | 162c1c1f | Guido Trotter | try:
|
722 | 008b92fa | Michael Hanselmann | # We already got the lock, notify now
|
723 | 008b92fa | Michael Hanselmann | if __debug__ and callable(test_notify): |
724 | 008b92fa | Michael Hanselmann | test_notify() |
725 | 008b92fa | Michael Hanselmann | |
726 | 887c7aa6 | Michael Hanselmann | return self.__acquire_unlocked(shared, timeout, priority) |
727 | 162c1c1f | Guido Trotter | finally:
|
728 | 162c1c1f | Guido Trotter | self.__lock.release()
|
729 | 162c1c1f | Guido Trotter | |
730 | 3dbe3ddf | Michael Hanselmann | def downgrade(self): |
731 | 3dbe3ddf | Michael Hanselmann | """Changes the lock mode from exclusive to shared.
|
732 | 3dbe3ddf | Michael Hanselmann |
|
733 | 3dbe3ddf | Michael Hanselmann | Pending acquires in shared mode on the same priority will go ahead.
|
734 | 3dbe3ddf | Michael Hanselmann |
|
735 | 3dbe3ddf | Michael Hanselmann | """
|
736 | 3dbe3ddf | Michael Hanselmann | self.__lock.acquire()
|
737 | 3dbe3ddf | Michael Hanselmann | try:
|
738 | 3dbe3ddf | Michael Hanselmann | assert self.__is_owned(), "Lock must be owned" |
739 | 3dbe3ddf | Michael Hanselmann | |
740 | 3dbe3ddf | Michael Hanselmann | if self.__is_exclusive(): |
741 | 3dbe3ddf | Michael Hanselmann | # Do nothing if the lock is already acquired in shared mode
|
742 | 3dbe3ddf | Michael Hanselmann | self.__exc = None |
743 | 3dbe3ddf | Michael Hanselmann | self.__do_acquire(1) |
744 | 3dbe3ddf | Michael Hanselmann | |
745 | 3dbe3ddf | Michael Hanselmann | # Important: pending shared acquires should only jump ahead if there
|
746 | 3dbe3ddf | Michael Hanselmann | # was a transition from exclusive to shared, otherwise an owner of a
|
747 | 3dbe3ddf | Michael Hanselmann | # shared lock can keep calling this function to push incoming shared
|
748 | 3dbe3ddf | Michael Hanselmann | # acquires
|
749 | 3dbe3ddf | Michael Hanselmann | (priority, prioqueue) = self.__find_first_pending_queue()
|
750 | 3dbe3ddf | Michael Hanselmann | if prioqueue:
|
751 | 3dbe3ddf | Michael Hanselmann | # Is there a pending shared acquire on this priority?
|
752 | 3dbe3ddf | Michael Hanselmann | cond = self.__pending_shared.pop(priority, None) |
753 | 3dbe3ddf | Michael Hanselmann | if cond:
|
754 | 3dbe3ddf | Michael Hanselmann | assert cond.shared
|
755 | 3dbe3ddf | Michael Hanselmann | assert cond in prioqueue |
756 | 3dbe3ddf | Michael Hanselmann | |
757 | 3dbe3ddf | Michael Hanselmann | # Ensure shared acquire is on top of queue
|
758 | 3dbe3ddf | Michael Hanselmann | if len(prioqueue) > 1: |
759 | 3dbe3ddf | Michael Hanselmann | prioqueue.remove(cond) |
760 | 3dbe3ddf | Michael Hanselmann | prioqueue.insert(0, cond)
|
761 | 3dbe3ddf | Michael Hanselmann | |
762 | 3dbe3ddf | Michael Hanselmann | # Notify
|
763 | 3dbe3ddf | Michael Hanselmann | cond.notifyAll() |
764 | 3dbe3ddf | Michael Hanselmann | |
765 | 3dbe3ddf | Michael Hanselmann | assert not self.__is_exclusive() |
766 | 3dbe3ddf | Michael Hanselmann | assert self.__is_sharer() |
767 | 3dbe3ddf | Michael Hanselmann | |
768 | 3dbe3ddf | Michael Hanselmann | return True |
769 | 3dbe3ddf | Michael Hanselmann | finally:
|
770 | 3dbe3ddf | Michael Hanselmann | self.__lock.release()
|
771 | 3dbe3ddf | Michael Hanselmann | |
772 | 162c1c1f | Guido Trotter | def release(self): |
773 | 162c1c1f | Guido Trotter | """Release a Shared Lock.
|
774 | 162c1c1f | Guido Trotter |
|
775 | 162c1c1f | Guido Trotter | You must have acquired the lock, either in shared or in exclusive mode,
|
776 | 162c1c1f | Guido Trotter | before calling this function.
|
777 | 162c1c1f | Guido Trotter |
|
778 | 162c1c1f | Guido Trotter | """
|
779 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
780 | 162c1c1f | Guido Trotter | try:
|
781 | 84e344d4 | Michael Hanselmann | assert self.__is_exclusive() or self.__is_sharer(), \ |
782 | 84e344d4 | Michael Hanselmann | "Cannot release non-owned lock"
|
783 | 84e344d4 | Michael Hanselmann | |
784 | 162c1c1f | Guido Trotter | # Autodetect release type
|
785 | 162c1c1f | Guido Trotter | if self.__is_exclusive(): |
786 | 162c1c1f | Guido Trotter | self.__exc = None |
787 | 84e344d4 | Michael Hanselmann | else:
|
788 | 162c1c1f | Guido Trotter | self.__shr.remove(threading.currentThread())
|
789 | 162c1c1f | Guido Trotter | |
790 | 84e344d4 | Michael Hanselmann | # Notify topmost condition in queue
|
791 | 113359fe | Michael Hanselmann | (priority, prioqueue) = self.__find_first_pending_queue()
|
792 | 887c7aa6 | Michael Hanselmann | if prioqueue:
|
793 | 113359fe | Michael Hanselmann | cond = prioqueue[0]
|
794 | 113359fe | Michael Hanselmann | cond.notifyAll() |
795 | 113359fe | Michael Hanselmann | if cond.shared:
|
796 | 113359fe | Michael Hanselmann | # Prevent further shared acquires from sneaking in while waiters are
|
797 | 113359fe | Michael Hanselmann | # notified
|
798 | 113359fe | Michael Hanselmann | self.__pending_shared.pop(priority, None) |
799 | 162c1c1f | Guido Trotter | |
800 | 162c1c1f | Guido Trotter | finally:
|
801 | 162c1c1f | Guido Trotter | self.__lock.release()
|
802 | 162c1c1f | Guido Trotter | |
803 | 7100c2fa | Michael Hanselmann | def delete(self, timeout=None, priority=None): |
804 | a95fd5d7 | Guido Trotter | """Delete a Shared Lock.
|
805 | a95fd5d7 | Guido Trotter |
|
806 | a95fd5d7 | Guido Trotter | This operation will declare the lock for removal. First the lock will be
|
807 | a95fd5d7 | Guido Trotter | acquired in exclusive mode if you don't already own it, then the lock
|
808 | a95fd5d7 | Guido Trotter | will be put in a state where any future and pending acquire() fail.
|
809 | a95fd5d7 | Guido Trotter |
|
810 | 84e344d4 | Michael Hanselmann | @type timeout: float
|
811 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
812 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
813 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
814 | a95fd5d7 | Guido Trotter |
|
815 | a95fd5d7 | Guido Trotter | """
|
816 | 7100c2fa | Michael Hanselmann | if priority is None: |
817 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
818 | 7100c2fa | Michael Hanselmann | |
819 | a95fd5d7 | Guido Trotter | self.__lock.acquire()
|
820 | a95fd5d7 | Guido Trotter | try:
|
821 | 84e344d4 | Michael Hanselmann | assert not self.__is_sharer(), "Cannot delete() a lock while sharing it" |
822 | 84e344d4 | Michael Hanselmann | |
823 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
824 | a95fd5d7 | Guido Trotter | |
825 | 84e344d4 | Michael Hanselmann | # The caller is allowed to hold the lock exclusively already.
|
826 | 84e344d4 | Michael Hanselmann | acquired = self.__is_exclusive()
|
827 | a95fd5d7 | Guido Trotter | |
828 | 84e344d4 | Michael Hanselmann | if not acquired: |
829 | 887c7aa6 | Michael Hanselmann | acquired = self.__acquire_unlocked(0, timeout, priority) |
830 | a66bd91b | Michael Hanselmann | |
831 | a66bd91b | Michael Hanselmann | assert self.__is_exclusive() and not self.__is_sharer(), \ |
832 | a66bd91b | Michael Hanselmann | "Lock wasn't acquired in exclusive mode"
|
833 | 84e344d4 | Michael Hanselmann | |
834 | 84e344d4 | Michael Hanselmann | if acquired:
|
835 | 84e344d4 | Michael Hanselmann | self.__deleted = True |
836 | 84e344d4 | Michael Hanselmann | self.__exc = None |
837 | a95fd5d7 | Guido Trotter | |
838 | 19b9ba9a | Michael Hanselmann | assert not (self.__exc or self.__shr), "Found owner during deletion" |
839 | 19b9ba9a | Michael Hanselmann | |
840 | 84e344d4 | Michael Hanselmann | # Notify all acquires. They'll throw an error.
|
841 | 887c7aa6 | Michael Hanselmann | for (_, prioqueue) in self.__pending: |
842 | 887c7aa6 | Michael Hanselmann | for cond in prioqueue: |
843 | 887c7aa6 | Michael Hanselmann | cond.notifyAll() |
844 | 887c7aa6 | Michael Hanselmann | |
845 | 887c7aa6 | Michael Hanselmann | assert self.__deleted |
846 | a95fd5d7 | Guido Trotter | |
847 | 84e344d4 | Michael Hanselmann | return acquired
|
848 | a95fd5d7 | Guido Trotter | finally:
|
849 | a95fd5d7 | Guido Trotter | self.__lock.release()
|
850 | a95fd5d7 | Guido Trotter | |
851 | 1a4e32d0 | Guido Trotter | def _release_save(self): |
852 | 1a4e32d0 | Guido Trotter | shared = self.__is_sharer()
|
853 | 1a4e32d0 | Guido Trotter | self.release()
|
854 | 1a4e32d0 | Guido Trotter | return shared
|
855 | 1a4e32d0 | Guido Trotter | |
856 | 1a4e32d0 | Guido Trotter | def _acquire_restore(self, shared): |
857 | 1a4e32d0 | Guido Trotter | self.acquire(shared=shared)
|
858 | 1a4e32d0 | Guido Trotter | |
859 | aaae9bc0 | Guido Trotter | |
860 | f12eadb3 | Iustin Pop | # Whenever we want to acquire a full LockSet we pass None as the value
|
861 | 5bbd3f7f | Michael Hanselmann | # to acquire. Hide this behind this nicely named constant.
|
862 | e310b019 | Guido Trotter | ALL_SET = None
|
863 | e310b019 | Guido Trotter | |
864 | e310b019 | Guido Trotter | |
865 | 5aab242c | Michael Hanselmann | class _AcquireTimeout(Exception): |
866 | 5aab242c | Michael Hanselmann | """Internal exception to abort an acquire on a timeout.
|
867 | 5aab242c | Michael Hanselmann |
|
868 | 5aab242c | Michael Hanselmann | """
|
869 | 5aab242c | Michael Hanselmann | |
870 | 5aab242c | Michael Hanselmann | |
871 | aaae9bc0 | Guido Trotter | class LockSet: |
872 | aaae9bc0 | Guido Trotter | """Implements a set of locks.
|
873 | aaae9bc0 | Guido Trotter |
|
874 | aaae9bc0 | Guido Trotter | This abstraction implements a set of shared locks for the same resource type,
|
875 | aaae9bc0 | Guido Trotter | distinguished by name. The user can lock a subset of the resources and the
|
876 | aaae9bc0 | Guido Trotter | LockSet will take care of acquiring the locks always in the same order, thus
|
877 | aaae9bc0 | Guido Trotter | preventing deadlock.
|
878 | aaae9bc0 | Guido Trotter |
|
879 | aaae9bc0 | Guido Trotter | All the locks needed in the same set must be acquired together, though.
|
880 | aaae9bc0 | Guido Trotter |
|
881 | 7f93570a | Iustin Pop | @type name: string
|
882 | 7f93570a | Iustin Pop | @ivar name: the name of the lockset
|
883 | 7f93570a | Iustin Pop |
|
884 | aaae9bc0 | Guido Trotter | """
|
885 | 19b9ba9a | Michael Hanselmann | def __init__(self, members, name, monitor=None): |
886 | aaae9bc0 | Guido Trotter | """Constructs a new LockSet.
|
887 | aaae9bc0 | Guido Trotter |
|
888 | ec44d893 | Guido Trotter | @type members: list of strings
|
889 | c41eea6e | Iustin Pop | @param members: initial members of the set
|
890 | 19b9ba9a | Michael Hanselmann | @type monitor: L{LockMonitor}
|
891 | 19b9ba9a | Michael Hanselmann | @param monitor: Lock monitor with which to register member locks
|
892 | aaae9bc0 | Guido Trotter |
|
893 | aaae9bc0 | Guido Trotter | """
|
894 | 7f93570a | Iustin Pop | assert members is not None, "members parameter is not a list" |
895 | 7f93570a | Iustin Pop | self.name = name
|
896 | 7f93570a | Iustin Pop | |
897 | 19b9ba9a | Michael Hanselmann | # Lock monitor
|
898 | 19b9ba9a | Michael Hanselmann | self.__monitor = monitor
|
899 | 19b9ba9a | Michael Hanselmann | |
900 | c307ee34 | Michael Hanselmann | # Used internally to guarantee coherency
|
901 | c307ee34 | Michael Hanselmann | self.__lock = SharedLock(self._GetLockName("[lockset]"), monitor=monitor) |
902 | aaae9bc0 | Guido Trotter | |
903 | aaae9bc0 | Guido Trotter | # The lockdict indexes the relationship name -> lock
|
904 | aaae9bc0 | Guido Trotter | # The order-of-locking is implied by the alphabetical order of names
|
905 | aaae9bc0 | Guido Trotter | self.__lockdict = {}
|
906 | aaae9bc0 | Guido Trotter | |
907 | 7f93570a | Iustin Pop | for mname in members: |
908 | 19b9ba9a | Michael Hanselmann | self.__lockdict[mname] = SharedLock(self._GetLockName(mname), |
909 | 19b9ba9a | Michael Hanselmann | monitor=monitor) |
910 | aaae9bc0 | Guido Trotter | |
911 | aaae9bc0 | Guido Trotter | # The owner dict contains the set of locks each thread owns. For
|
912 | aaae9bc0 | Guido Trotter | # performance each thread can access its own key without a global lock on
|
913 | aaae9bc0 | Guido Trotter | # this structure. It is paramount though that *no* other type of access is
|
914 | aaae9bc0 | Guido Trotter | # done to this structure (eg. no looping over its keys). *_owner helper
|
915 | aaae9bc0 | Guido Trotter | # function are defined to guarantee access is correct, but in general never
|
916 | aaae9bc0 | Guido Trotter | # do anything different than __owners[threading.currentThread()], or there
|
917 | aaae9bc0 | Guido Trotter | # will be trouble.
|
918 | aaae9bc0 | Guido Trotter | self.__owners = {}
|
919 | aaae9bc0 | Guido Trotter | |
920 | 4fb780d1 | Michael Hanselmann | def _GetLockName(self, mname): |
921 | 4fb780d1 | Michael Hanselmann | """Returns the name for a member lock.
|
922 | 4fb780d1 | Michael Hanselmann |
|
923 | 4fb780d1 | Michael Hanselmann | """
|
924 | 4fb780d1 | Michael Hanselmann | return "%s/%s" % (self.name, mname) |
925 | 4fb780d1 | Michael Hanselmann | |
926 | 3dbe3ddf | Michael Hanselmann | def _get_lock(self): |
927 | 3dbe3ddf | Michael Hanselmann | """Returns the lockset-internal lock.
|
928 | 3dbe3ddf | Michael Hanselmann |
|
929 | 3dbe3ddf | Michael Hanselmann | """
|
930 | 3dbe3ddf | Michael Hanselmann | return self.__lock |
931 | 3dbe3ddf | Michael Hanselmann | |
932 | 3dbe3ddf | Michael Hanselmann | def _get_lockdict(self): |
933 | 3dbe3ddf | Michael Hanselmann | """Returns the lockset-internal lock dictionary.
|
934 | 3dbe3ddf | Michael Hanselmann |
|
935 | 3dbe3ddf | Michael Hanselmann | Accessing this structure is only safe in single-thread usage or when the
|
936 | 3dbe3ddf | Michael Hanselmann | lockset-internal lock is held.
|
937 | 3dbe3ddf | Michael Hanselmann |
|
938 | 3dbe3ddf | Michael Hanselmann | """
|
939 | 3dbe3ddf | Michael Hanselmann | return self.__lockdict |
940 | 3dbe3ddf | Michael Hanselmann | |
941 | aaae9bc0 | Guido Trotter | def _is_owned(self): |
942 | aaae9bc0 | Guido Trotter | """Is the current thread a current level owner?"""
|
943 | aaae9bc0 | Guido Trotter | return threading.currentThread() in self.__owners |
944 | aaae9bc0 | Guido Trotter | |
945 | b2dabfd6 | Guido Trotter | def _add_owned(self, name=None): |
946 | aaae9bc0 | Guido Trotter | """Note the current thread owns the given lock"""
|
947 | b2dabfd6 | Guido Trotter | if name is None: |
948 | b2dabfd6 | Guido Trotter | if not self._is_owned(): |
949 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()] = set() |
950 | aaae9bc0 | Guido Trotter | else:
|
951 | b2dabfd6 | Guido Trotter | if self._is_owned(): |
952 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()].add(name)
|
953 | b2dabfd6 | Guido Trotter | else:
|
954 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()] = set([name]) |
955 | b2dabfd6 | Guido Trotter | |
956 | b2dabfd6 | Guido Trotter | def _del_owned(self, name=None): |
957 | aaae9bc0 | Guido Trotter | """Note the current thread owns the given lock"""
|
958 | aaae9bc0 | Guido Trotter | |
959 | e4335b5b | Michael Hanselmann | assert not (name is None and self.__lock._is_owned()), \ |
960 | e4335b5b | Michael Hanselmann | "Cannot hold internal lock when deleting owner status"
|
961 | e4335b5b | Michael Hanselmann | |
962 | b2dabfd6 | Guido Trotter | if name is not None: |
963 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()].remove(name)
|
964 | b2dabfd6 | Guido Trotter | |
965 | b2dabfd6 | Guido Trotter | # Only remove the key if we don't hold the set-lock as well
|
966 | b2dabfd6 | Guido Trotter | if (not self.__lock._is_owned() and |
967 | b2dabfd6 | Guido Trotter | not self.__owners[threading.currentThread()]): |
968 | aaae9bc0 | Guido Trotter | del self.__owners[threading.currentThread()] |
969 | aaae9bc0 | Guido Trotter | |
970 | aaae9bc0 | Guido Trotter | def _list_owned(self): |
971 | aaae9bc0 | Guido Trotter | """Get the set of resource names owned by the current thread"""
|
972 | aaae9bc0 | Guido Trotter | if self._is_owned(): |
973 | aaae9bc0 | Guido Trotter | return self.__owners[threading.currentThread()].copy() |
974 | aaae9bc0 | Guido Trotter | else:
|
975 | aaae9bc0 | Guido Trotter | return set() |
976 | aaae9bc0 | Guido Trotter | |
977 | 5aab242c | Michael Hanselmann | def _release_and_delete_owned(self): |
978 | 5aab242c | Michael Hanselmann | """Release and delete all resources owned by the current thread"""
|
979 | 5aab242c | Michael Hanselmann | for lname in self._list_owned(): |
980 | 56452af7 | Michael Hanselmann | lock = self.__lockdict[lname]
|
981 | 56452af7 | Michael Hanselmann | if lock._is_owned():
|
982 | 56452af7 | Michael Hanselmann | lock.release() |
983 | 5aab242c | Michael Hanselmann | self._del_owned(name=lname)
|
984 | 5aab242c | Michael Hanselmann | |
985 | aaae9bc0 | Guido Trotter | def __names(self): |
986 | aaae9bc0 | Guido Trotter | """Return the current set of names.
|
987 | aaae9bc0 | Guido Trotter |
|
988 | aaae9bc0 | Guido Trotter | Only call this function while holding __lock and don't iterate on the
|
989 | aaae9bc0 | Guido Trotter | result after releasing the lock.
|
990 | aaae9bc0 | Guido Trotter |
|
991 | aaae9bc0 | Guido Trotter | """
|
992 | 0cf257c5 | Guido Trotter | return self.__lockdict.keys() |
993 | aaae9bc0 | Guido Trotter | |
994 | aaae9bc0 | Guido Trotter | def _names(self): |
995 | aaae9bc0 | Guido Trotter | """Return a copy of the current set of elements.
|
996 | aaae9bc0 | Guido Trotter |
|
997 | aaae9bc0 | Guido Trotter | Used only for debugging purposes.
|
998 | cdb08f44 | Michael Hanselmann |
|
999 | aaae9bc0 | Guido Trotter | """
|
1000 | d4803c24 | Guido Trotter | # If we don't already own the set-level lock acquired
|
1001 | d4803c24 | Guido Trotter | # we'll get it and note we need to release it later.
|
1002 | d4803c24 | Guido Trotter | release_lock = False
|
1003 | d4803c24 | Guido Trotter | if not self.__lock._is_owned(): |
1004 | d4803c24 | Guido Trotter | release_lock = True
|
1005 | d4803c24 | Guido Trotter | self.__lock.acquire(shared=1) |
1006 | aaae9bc0 | Guido Trotter | try:
|
1007 | aaae9bc0 | Guido Trotter | result = self.__names()
|
1008 | aaae9bc0 | Guido Trotter | finally:
|
1009 | d4803c24 | Guido Trotter | if release_lock:
|
1010 | d4803c24 | Guido Trotter | self.__lock.release()
|
1011 | 0cf257c5 | Guido Trotter | return set(result) |
1012 | aaae9bc0 | Guido Trotter | |
1013 | 7100c2fa | Michael Hanselmann | def acquire(self, names, timeout=None, shared=0, priority=None, |
1014 | 887c7aa6 | Michael Hanselmann | test_notify=None):
|
1015 | aaae9bc0 | Guido Trotter | """Acquire a set of resource locks.
|
1016 | aaae9bc0 | Guido Trotter |
|
1017 | ec44d893 | Guido Trotter | @type names: list of strings (or string)
|
1018 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be acquired
|
1019 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1020 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1021 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default an
|
1022 | c41eea6e | Iustin Pop | exclusive lock will be acquired
|
1023 | 5aab242c | Michael Hanselmann | @type timeout: float or None
|
1024 | 5e0a6daf | Michael Hanselmann | @param timeout: Maximum time to acquire all locks
|
1025 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
1026 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring locks
|
1027 | 5aab242c | Michael Hanselmann | @type test_notify: callable or None
|
1028 | 5aab242c | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
1029 | aaae9bc0 | Guido Trotter |
|
1030 | 5aab242c | Michael Hanselmann | @return: Set of all locks successfully acquired or None in case of timeout
|
1031 | aaae9bc0 | Guido Trotter |
|
1032 | c41eea6e | Iustin Pop | @raise errors.LockError: when any lock we try to acquire has
|
1033 | c41eea6e | Iustin Pop | been deleted before we succeed. In this case none of the
|
1034 | c41eea6e | Iustin Pop | locks requested will be acquired.
|
1035 | aaae9bc0 | Guido Trotter |
|
1036 | aaae9bc0 | Guido Trotter | """
|
1037 | 5aab242c | Michael Hanselmann | assert timeout is None or timeout >= 0.0 |
1038 | aaae9bc0 | Guido Trotter | |
1039 | aaae9bc0 | Guido Trotter | # Check we don't already own locks at this level
|
1040 | 7f93570a | Iustin Pop | assert not self._is_owned(), ("Cannot acquire locks in the same set twice" |
1041 | 7f93570a | Iustin Pop | " (lockset %s)" % self.name) |
1042 | aaae9bc0 | Guido Trotter | |
1043 | 7100c2fa | Michael Hanselmann | if priority is None: |
1044 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
1045 | 7100c2fa | Michael Hanselmann | |
1046 | 5aab242c | Michael Hanselmann | # We need to keep track of how long we spent waiting for a lock. The
|
1047 | 5aab242c | Michael Hanselmann | # timeout passed to this function is over all lock acquires.
|
1048 | 557838c1 | René Nussbaumer | running_timeout = utils.RunningTimeout(timeout, False)
|
1049 | 5aab242c | Michael Hanselmann | |
1050 | 806e20fd | Guido Trotter | try:
|
1051 | 76e2f08a | Michael Hanselmann | if names is not None: |
1052 | 5aab242c | Michael Hanselmann | # Support passing in a single resource to acquire rather than many
|
1053 | 5aab242c | Michael Hanselmann | if isinstance(names, basestring): |
1054 | 5aab242c | Michael Hanselmann | names = [names] |
1055 | 5aab242c | Michael Hanselmann | |
1056 | 887c7aa6 | Michael Hanselmann | return self.__acquire_inner(names, False, shared, priority, |
1057 | 7e8841bd | Michael Hanselmann | running_timeout.Remaining, test_notify) |
1058 | 76e2f08a | Michael Hanselmann | |
1059 | 76e2f08a | Michael Hanselmann | else:
|
1060 | 76e2f08a | Michael Hanselmann | # If no names are given acquire the whole set by not letting new names
|
1061 | 76e2f08a | Michael Hanselmann | # being added before we release, and getting the current list of names.
|
1062 | 76e2f08a | Michael Hanselmann | # Some of them may then be deleted later, but we'll cope with this.
|
1063 | 76e2f08a | Michael Hanselmann | #
|
1064 | 76e2f08a | Michael Hanselmann | # We'd like to acquire this lock in a shared way, as it's nice if
|
1065 | 887c7aa6 | Michael Hanselmann | # everybody else can use the instances at the same time. If we are
|
1066 | 76e2f08a | Michael Hanselmann | # acquiring them exclusively though they won't be able to do this
|
1067 | 76e2f08a | Michael Hanselmann | # anyway, though, so we'll get the list lock exclusively as well in
|
1068 | 76e2f08a | Michael Hanselmann | # order to be able to do add() on the set while owning it.
|
1069 | 887c7aa6 | Michael Hanselmann | if not self.__lock.acquire(shared=shared, priority=priority, |
1070 | 7e8841bd | Michael Hanselmann | timeout=running_timeout.Remaining()): |
1071 | 76e2f08a | Michael Hanselmann | raise _AcquireTimeout()
|
1072 | 76e2f08a | Michael Hanselmann | try:
|
1073 | 76e2f08a | Michael Hanselmann | # note we own the set-lock
|
1074 | 76e2f08a | Michael Hanselmann | self._add_owned()
|
1075 | 76e2f08a | Michael Hanselmann | |
1076 | 887c7aa6 | Michael Hanselmann | return self.__acquire_inner(self.__names(), True, shared, priority, |
1077 | 7e8841bd | Michael Hanselmann | running_timeout.Remaining, test_notify) |
1078 | 76e2f08a | Michael Hanselmann | except:
|
1079 | 76e2f08a | Michael Hanselmann | # We shouldn't have problems adding the lock to the owners list, but
|
1080 | 76e2f08a | Michael Hanselmann | # if we did we'll try to release this lock and re-raise exception.
|
1081 | 76e2f08a | Michael Hanselmann | # Of course something is going to be really wrong, after this.
|
1082 | 5aab242c | Michael Hanselmann | self.__lock.release()
|
1083 | 76e2f08a | Michael Hanselmann | self._del_owned()
|
1084 | 76e2f08a | Michael Hanselmann | raise
|
1085 | 5aab242c | Michael Hanselmann | |
1086 | 5aab242c | Michael Hanselmann | except _AcquireTimeout:
|
1087 | 5aab242c | Michael Hanselmann | return None |
1088 | aaae9bc0 | Guido Trotter | |
1089 | 887c7aa6 | Michael Hanselmann | def __acquire_inner(self, names, want_all, shared, priority, |
1090 | 887c7aa6 | Michael Hanselmann | timeout_fn, test_notify): |
1091 | 7e8841bd | Michael Hanselmann | """Inner logic for acquiring a number of locks.
|
1092 | 7e8841bd | Michael Hanselmann |
|
1093 | 7e8841bd | Michael Hanselmann | @param names: Names of the locks to be acquired
|
1094 | 7e8841bd | Michael Hanselmann | @param want_all: Whether all locks in the set should be acquired
|
1095 | 7e8841bd | Michael Hanselmann | @param shared: Whether to acquire in shared mode
|
1096 | 7e8841bd | Michael Hanselmann | @param timeout_fn: Function returning remaining timeout
|
1097 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring locks
|
1098 | 7e8841bd | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
1099 | 76e2f08a | Michael Hanselmann |
|
1100 | 76e2f08a | Michael Hanselmann | """
|
1101 | 76e2f08a | Michael Hanselmann | acquire_list = [] |
1102 | 76e2f08a | Michael Hanselmann | |
1103 | 76e2f08a | Michael Hanselmann | # First we look the locks up on __lockdict. We have no way of being sure
|
1104 | 76e2f08a | Michael Hanselmann | # they will still be there after, but this makes it a lot faster should
|
1105 | 71e1863e | Michael Hanselmann | # just one of them be the already wrong. Using a sorted sequence to prevent
|
1106 | 71e1863e | Michael Hanselmann | # deadlocks.
|
1107 | 71e1863e | Michael Hanselmann | for lname in sorted(utils.UniqueSequence(names)): |
1108 | 76e2f08a | Michael Hanselmann | try:
|
1109 | 76e2f08a | Michael Hanselmann | lock = self.__lockdict[lname] # raises KeyError if lock is not there |
1110 | 76e2f08a | Michael Hanselmann | except KeyError: |
1111 | 76e2f08a | Michael Hanselmann | if want_all:
|
1112 | 76e2f08a | Michael Hanselmann | # We are acquiring all the set, it doesn't matter if this particular
|
1113 | 76e2f08a | Michael Hanselmann | # element is not there anymore.
|
1114 | 76e2f08a | Michael Hanselmann | continue
|
1115 | 76e2f08a | Michael Hanselmann | |
1116 | e1137eb6 | Michael Hanselmann | raise errors.LockError("Non-existing lock %s in set %s (it may have" |
1117 | e1137eb6 | Michael Hanselmann | " been removed)" % (lname, self.name)) |
1118 | 76e2f08a | Michael Hanselmann | |
1119 | 9b154270 | Michael Hanselmann | acquire_list.append((lname, lock)) |
1120 | 9b154270 | Michael Hanselmann | |
1121 | 76e2f08a | Michael Hanselmann | # This will hold the locknames we effectively acquired.
|
1122 | 76e2f08a | Michael Hanselmann | acquired = set()
|
1123 | 76e2f08a | Michael Hanselmann | |
1124 | 76e2f08a | Michael Hanselmann | try:
|
1125 | 76e2f08a | Michael Hanselmann | # Now acquire_list contains a sorted list of resources and locks we
|
1126 | 76e2f08a | Michael Hanselmann | # want. In order to get them we loop on this (private) list and
|
1127 | 76e2f08a | Michael Hanselmann | # acquire() them. We gave no real guarantee they will still exist till
|
1128 | 76e2f08a | Michael Hanselmann | # this is done but .acquire() itself is safe and will alert us if the
|
1129 | 76e2f08a | Michael Hanselmann | # lock gets deleted.
|
1130 | 76e2f08a | Michael Hanselmann | for (lname, lock) in acquire_list: |
1131 | 76e2f08a | Michael Hanselmann | if __debug__ and callable(test_notify): |
1132 | 76e2f08a | Michael Hanselmann | test_notify_fn = lambda: test_notify(lname)
|
1133 | 76e2f08a | Michael Hanselmann | else:
|
1134 | 76e2f08a | Michael Hanselmann | test_notify_fn = None
|
1135 | 76e2f08a | Michael Hanselmann | |
1136 | 76e2f08a | Michael Hanselmann | timeout = timeout_fn() |
1137 | 76e2f08a | Michael Hanselmann | |
1138 | 76e2f08a | Michael Hanselmann | try:
|
1139 | 76e2f08a | Michael Hanselmann | # raises LockError if the lock was deleted
|
1140 | 76e2f08a | Michael Hanselmann | acq_success = lock.acquire(shared=shared, timeout=timeout, |
1141 | 887c7aa6 | Michael Hanselmann | priority=priority, |
1142 | 76e2f08a | Michael Hanselmann | test_notify=test_notify_fn) |
1143 | 76e2f08a | Michael Hanselmann | except errors.LockError:
|
1144 | 76e2f08a | Michael Hanselmann | if want_all:
|
1145 | 76e2f08a | Michael Hanselmann | # We are acquiring all the set, it doesn't matter if this
|
1146 | 76e2f08a | Michael Hanselmann | # particular element is not there anymore.
|
1147 | 76e2f08a | Michael Hanselmann | continue
|
1148 | 76e2f08a | Michael Hanselmann | |
1149 | e1137eb6 | Michael Hanselmann | raise errors.LockError("Non-existing lock %s in set %s (it may" |
1150 | e1137eb6 | Michael Hanselmann | " have been removed)" % (lname, self.name)) |
1151 | 76e2f08a | Michael Hanselmann | |
1152 | 76e2f08a | Michael Hanselmann | if not acq_success: |
1153 | 76e2f08a | Michael Hanselmann | # Couldn't get lock or timeout occurred
|
1154 | 76e2f08a | Michael Hanselmann | if timeout is None: |
1155 | 76e2f08a | Michael Hanselmann | # This shouldn't happen as SharedLock.acquire(timeout=None) is
|
1156 | 76e2f08a | Michael Hanselmann | # blocking.
|
1157 | 7f93570a | Iustin Pop | raise errors.LockError("Failed to get lock %s (set %s)" % |
1158 | 7f93570a | Iustin Pop | (lname, self.name))
|
1159 | 76e2f08a | Michael Hanselmann | |
1160 | 76e2f08a | Michael Hanselmann | raise _AcquireTimeout()
|
1161 | 76e2f08a | Michael Hanselmann | |
1162 | 76e2f08a | Michael Hanselmann | try:
|
1163 | 76e2f08a | Michael Hanselmann | # now the lock cannot be deleted, we have it!
|
1164 | 76e2f08a | Michael Hanselmann | self._add_owned(name=lname)
|
1165 | 76e2f08a | Michael Hanselmann | acquired.add(lname) |
1166 | 76e2f08a | Michael Hanselmann | |
1167 | 76e2f08a | Michael Hanselmann | except:
|
1168 | 76e2f08a | Michael Hanselmann | # We shouldn't have problems adding the lock to the owners list, but
|
1169 | 76e2f08a | Michael Hanselmann | # if we did we'll try to release this lock and re-raise exception.
|
1170 | 76e2f08a | Michael Hanselmann | # Of course something is going to be really wrong after this.
|
1171 | 76e2f08a | Michael Hanselmann | if lock._is_owned():
|
1172 | 76e2f08a | Michael Hanselmann | lock.release() |
1173 | 76e2f08a | Michael Hanselmann | raise
|
1174 | 76e2f08a | Michael Hanselmann | |
1175 | 76e2f08a | Michael Hanselmann | except:
|
1176 | 76e2f08a | Michael Hanselmann | # Release all owned locks
|
1177 | 76e2f08a | Michael Hanselmann | self._release_and_delete_owned()
|
1178 | 76e2f08a | Michael Hanselmann | raise
|
1179 | 76e2f08a | Michael Hanselmann | |
1180 | 0cc00929 | Guido Trotter | return acquired
|
1181 | aaae9bc0 | Guido Trotter | |
1182 | 3dbe3ddf | Michael Hanselmann | def downgrade(self, names=None): |
1183 | 3dbe3ddf | Michael Hanselmann | """Downgrade a set of resource locks from exclusive to shared mode.
|
1184 | 3dbe3ddf | Michael Hanselmann |
|
1185 | 3dbe3ddf | Michael Hanselmann | The locks must have been acquired in exclusive mode.
|
1186 | 3dbe3ddf | Michael Hanselmann |
|
1187 | 3dbe3ddf | Michael Hanselmann | """
|
1188 | 3dbe3ddf | Michael Hanselmann | assert self._is_owned(), ("downgrade on lockset %s while not owning any" |
1189 | 3dbe3ddf | Michael Hanselmann | " lock" % self.name) |
1190 | 3dbe3ddf | Michael Hanselmann | |
1191 | 3dbe3ddf | Michael Hanselmann | # Support passing in a single resource to downgrade rather than many
|
1192 | 3dbe3ddf | Michael Hanselmann | if isinstance(names, basestring): |
1193 | 3dbe3ddf | Michael Hanselmann | names = [names] |
1194 | 3dbe3ddf | Michael Hanselmann | |
1195 | 3dbe3ddf | Michael Hanselmann | owned = self._list_owned()
|
1196 | 3dbe3ddf | Michael Hanselmann | |
1197 | 3dbe3ddf | Michael Hanselmann | if names is None: |
1198 | 3dbe3ddf | Michael Hanselmann | names = owned |
1199 | 3dbe3ddf | Michael Hanselmann | else:
|
1200 | 3dbe3ddf | Michael Hanselmann | names = set(names)
|
1201 | 3dbe3ddf | Michael Hanselmann | assert owned.issuperset(names), \
|
1202 | 3dbe3ddf | Michael Hanselmann | ("downgrade() on unheld resources %s (set %s)" %
|
1203 | 3dbe3ddf | Michael Hanselmann | (names.difference(owned), self.name))
|
1204 | 3dbe3ddf | Michael Hanselmann | |
1205 | 3dbe3ddf | Michael Hanselmann | for lockname in names: |
1206 | 3dbe3ddf | Michael Hanselmann | self.__lockdict[lockname].downgrade()
|
1207 | 3dbe3ddf | Michael Hanselmann | |
1208 | 3dbe3ddf | Michael Hanselmann | # Do we own the lockset in exclusive mode?
|
1209 | 3dbe3ddf | Michael Hanselmann | if self.__lock._is_owned(shared=0): |
1210 | 3dbe3ddf | Michael Hanselmann | # Have all locks been downgraded?
|
1211 | 3dbe3ddf | Michael Hanselmann | if not compat.any(lock._is_owned(shared=0) |
1212 | 3dbe3ddf | Michael Hanselmann | for lock in self.__lockdict.values()): |
1213 | 3dbe3ddf | Michael Hanselmann | self.__lock.downgrade()
|
1214 | 3dbe3ddf | Michael Hanselmann | assert self.__lock._is_owned(shared=1) |
1215 | 3dbe3ddf | Michael Hanselmann | |
1216 | 3dbe3ddf | Michael Hanselmann | return True |
1217 | 3dbe3ddf | Michael Hanselmann | |
1218 | aaae9bc0 | Guido Trotter | def release(self, names=None): |
1219 | aaae9bc0 | Guido Trotter | """Release a set of resource locks, at the same level.
|
1220 | aaae9bc0 | Guido Trotter |
|
1221 | aaae9bc0 | Guido Trotter | You must have acquired the locks, either in shared or in exclusive mode,
|
1222 | aaae9bc0 | Guido Trotter | before releasing them.
|
1223 | aaae9bc0 | Guido Trotter |
|
1224 | ec44d893 | Guido Trotter | @type names: list of strings, or None
|
1225 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be released
|
1226 | c41eea6e | Iustin Pop | (defaults to all the locks acquired at that level).
|
1227 | aaae9bc0 | Guido Trotter |
|
1228 | aaae9bc0 | Guido Trotter | """
|
1229 | 7f93570a | Iustin Pop | assert self._is_owned(), ("release() on lock set %s while not owner" % |
1230 | 7f93570a | Iustin Pop | self.name)
|
1231 | aaae9bc0 | Guido Trotter | |
1232 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to release rather than many
|
1233 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1234 | aaae9bc0 | Guido Trotter | names = [names] |
1235 | aaae9bc0 | Guido Trotter | |
1236 | aaae9bc0 | Guido Trotter | if names is None: |
1237 | aaae9bc0 | Guido Trotter | names = self._list_owned()
|
1238 | aaae9bc0 | Guido Trotter | else:
|
1239 | aaae9bc0 | Guido Trotter | names = set(names)
|
1240 | aaae9bc0 | Guido Trotter | assert self._list_owned().issuperset(names), ( |
1241 | 7f93570a | Iustin Pop | "release() on unheld resources %s (set %s)" %
|
1242 | 7f93570a | Iustin Pop | (names.difference(self._list_owned()), self.name)) |
1243 | aaae9bc0 | Guido Trotter | |
1244 | 3b7ed473 | Guido Trotter | # First of all let's release the "all elements" lock, if set.
|
1245 | 3b7ed473 | Guido Trotter | # After this 'add' can work again
|
1246 | 3b7ed473 | Guido Trotter | if self.__lock._is_owned(): |
1247 | 3b7ed473 | Guido Trotter | self.__lock.release()
|
1248 | b2dabfd6 | Guido Trotter | self._del_owned()
|
1249 | 3b7ed473 | Guido Trotter | |
1250 | aaae9bc0 | Guido Trotter | for lockname in names: |
1251 | aaae9bc0 | Guido Trotter | # If we are sure the lock doesn't leave __lockdict without being
|
1252 | aaae9bc0 | Guido Trotter | # exclusively held we can do this...
|
1253 | aaae9bc0 | Guido Trotter | self.__lockdict[lockname].release()
|
1254 | b2dabfd6 | Guido Trotter | self._del_owned(name=lockname)
|
1255 | aaae9bc0 | Guido Trotter | |
1256 | aaae9bc0 | Guido Trotter | def add(self, names, acquired=0, shared=0): |
1257 | aaae9bc0 | Guido Trotter | """Add a new set of elements to the set
|
1258 | aaae9bc0 | Guido Trotter |
|
1259 | ec44d893 | Guido Trotter | @type names: list of strings
|
1260 | c41eea6e | Iustin Pop | @param names: names of the new elements to add
|
1261 | ec44d893 | Guido Trotter | @type acquired: integer (0/1) used as a boolean
|
1262 | c41eea6e | Iustin Pop | @param acquired: pre-acquire the new resource?
|
1263 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1264 | c41eea6e | Iustin Pop | @param shared: is the pre-acquisition shared?
|
1265 | aaae9bc0 | Guido Trotter |
|
1266 | aaae9bc0 | Guido Trotter | """
|
1267 | d2aff862 | Guido Trotter | # Check we don't already own locks at this level
|
1268 | d2aff862 | Guido Trotter | assert not self._is_owned() or self.__lock._is_owned(shared=0), \ |
1269 | 7f93570a | Iustin Pop | ("Cannot add locks if the set %s is only partially owned, or shared" %
|
1270 | 7f93570a | Iustin Pop | self.name)
|
1271 | 3b7ed473 | Guido Trotter | |
1272 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to add rather than many
|
1273 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1274 | aaae9bc0 | Guido Trotter | names = [names] |
1275 | aaae9bc0 | Guido Trotter | |
1276 | ab62526c | Guido Trotter | # If we don't already own the set-level lock acquired in an exclusive way
|
1277 | 3b7ed473 | Guido Trotter | # we'll get it and note we need to release it later.
|
1278 | 3b7ed473 | Guido Trotter | release_lock = False
|
1279 | 3b7ed473 | Guido Trotter | if not self.__lock._is_owned(): |
1280 | 3b7ed473 | Guido Trotter | release_lock = True
|
1281 | 3b7ed473 | Guido Trotter | self.__lock.acquire()
|
1282 | 3b7ed473 | Guido Trotter | |
1283 | aaae9bc0 | Guido Trotter | try:
|
1284 | 0cf257c5 | Guido Trotter | invalid_names = set(self.__names()).intersection(names) |
1285 | aaae9bc0 | Guido Trotter | if invalid_names:
|
1286 | aaae9bc0 | Guido Trotter | # This must be an explicit raise, not an assert, because assert is
|
1287 | aaae9bc0 | Guido Trotter | # turned off when using optimization, and this can happen because of
|
1288 | aaae9bc0 | Guido Trotter | # concurrency even if the user doesn't want it.
|
1289 | 7f93570a | Iustin Pop | raise errors.LockError("duplicate add(%s) on lockset %s" % |
1290 | 7f93570a | Iustin Pop | (invalid_names, self.name))
|
1291 | aaae9bc0 | Guido Trotter | |
1292 | aaae9bc0 | Guido Trotter | for lockname in names: |
1293 | 19b9ba9a | Michael Hanselmann | lock = SharedLock(self._GetLockName(lockname), monitor=self.__monitor) |
1294 | aaae9bc0 | Guido Trotter | |
1295 | aaae9bc0 | Guido Trotter | if acquired:
|
1296 | 887c7aa6 | Michael Hanselmann | # No need for priority or timeout here as this lock has just been
|
1297 | 887c7aa6 | Michael Hanselmann | # created
|
1298 | aaae9bc0 | Guido Trotter | lock.acquire(shared=shared) |
1299 | aaae9bc0 | Guido Trotter | # now the lock cannot be deleted, we have it!
|
1300 | aaae9bc0 | Guido Trotter | try:
|
1301 | b2dabfd6 | Guido Trotter | self._add_owned(name=lockname)
|
1302 | aaae9bc0 | Guido Trotter | except:
|
1303 | aaae9bc0 | Guido Trotter | # We shouldn't have problems adding the lock to the owners list,
|
1304 | aaae9bc0 | Guido Trotter | # but if we did we'll try to release this lock and re-raise
|
1305 | aaae9bc0 | Guido Trotter | # exception. Of course something is going to be really wrong,
|
1306 | aaae9bc0 | Guido Trotter | # after this. On the other hand the lock hasn't been added to the
|
1307 | aaae9bc0 | Guido Trotter | # __lockdict yet so no other threads should be pending on it. This
|
1308 | aaae9bc0 | Guido Trotter | # release is just a safety measure.
|
1309 | aaae9bc0 | Guido Trotter | lock.release() |
1310 | aaae9bc0 | Guido Trotter | raise
|
1311 | aaae9bc0 | Guido Trotter | |
1312 | aaae9bc0 | Guido Trotter | self.__lockdict[lockname] = lock
|
1313 | aaae9bc0 | Guido Trotter | |
1314 | aaae9bc0 | Guido Trotter | finally:
|
1315 | 3b7ed473 | Guido Trotter | # Only release __lock if we were not holding it previously.
|
1316 | 3b7ed473 | Guido Trotter | if release_lock:
|
1317 | 3b7ed473 | Guido Trotter | self.__lock.release()
|
1318 | aaae9bc0 | Guido Trotter | |
1319 | aaae9bc0 | Guido Trotter | return True |
1320 | aaae9bc0 | Guido Trotter | |
1321 | 5e0a6daf | Michael Hanselmann | def remove(self, names): |
1322 | aaae9bc0 | Guido Trotter | """Remove elements from the lock set.
|
1323 | aaae9bc0 | Guido Trotter |
|
1324 | aaae9bc0 | Guido Trotter | You can either not hold anything in the lockset or already hold a superset
|
1325 | aaae9bc0 | Guido Trotter | of the elements you want to delete, exclusively.
|
1326 | aaae9bc0 | Guido Trotter |
|
1327 | ec44d893 | Guido Trotter | @type names: list of strings
|
1328 | c41eea6e | Iustin Pop | @param names: names of the resource to remove.
|
1329 | aaae9bc0 | Guido Trotter |
|
1330 | 5aab242c | Michael Hanselmann | @return: a list of locks which we removed; the list is always
|
1331 | c41eea6e | Iustin Pop | equal to the names list if we were holding all the locks
|
1332 | c41eea6e | Iustin Pop | exclusively
|
1333 | aaae9bc0 | Guido Trotter |
|
1334 | aaae9bc0 | Guido Trotter | """
|
1335 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to remove rather than many
|
1336 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1337 | aaae9bc0 | Guido Trotter | names = [names] |
1338 | aaae9bc0 | Guido Trotter | |
1339 | aaae9bc0 | Guido Trotter | # If we own any subset of this lock it must be a superset of what we want
|
1340 | aaae9bc0 | Guido Trotter | # to delete. The ownership must also be exclusive, but that will be checked
|
1341 | aaae9bc0 | Guido Trotter | # by the lock itself.
|
1342 | aaae9bc0 | Guido Trotter | assert not self._is_owned() or self._list_owned().issuperset(names), ( |
1343 | 7f93570a | Iustin Pop | "remove() on acquired lockset %s while not owning all elements" %
|
1344 | 7f93570a | Iustin Pop | self.name)
|
1345 | aaae9bc0 | Guido Trotter | |
1346 | 3f404fc5 | Guido Trotter | removed = [] |
1347 | aaae9bc0 | Guido Trotter | |
1348 | aaae9bc0 | Guido Trotter | for lname in names: |
1349 | aaae9bc0 | Guido Trotter | # Calling delete() acquires the lock exclusively if we don't already own
|
1350 | aaae9bc0 | Guido Trotter | # it, and causes all pending and subsequent lock acquires to fail. It's
|
1351 | aaae9bc0 | Guido Trotter | # fine to call it out of order because delete() also implies release(),
|
1352 | aaae9bc0 | Guido Trotter | # and the assertion above guarantees that if we either already hold
|
1353 | aaae9bc0 | Guido Trotter | # everything we want to delete, or we hold none.
|
1354 | aaae9bc0 | Guido Trotter | try:
|
1355 | aaae9bc0 | Guido Trotter | self.__lockdict[lname].delete()
|
1356 | 3f404fc5 | Guido Trotter | removed.append(lname) |
1357 | aaae9bc0 | Guido Trotter | except (KeyError, errors.LockError): |
1358 | aaae9bc0 | Guido Trotter | # This cannot happen if we were already holding it, verify:
|
1359 | 7f93570a | Iustin Pop | assert not self._is_owned(), ("remove failed while holding lockset %s" |
1360 | 7f93570a | Iustin Pop | % self.name)
|
1361 | aaae9bc0 | Guido Trotter | else:
|
1362 | aaae9bc0 | Guido Trotter | # If no LockError was raised we are the ones who deleted the lock.
|
1363 | aaae9bc0 | Guido Trotter | # This means we can safely remove it from lockdict, as any further or
|
1364 | aaae9bc0 | Guido Trotter | # pending delete() or acquire() will fail (and nobody can have the lock
|
1365 | aaae9bc0 | Guido Trotter | # since before our call to delete()).
|
1366 | aaae9bc0 | Guido Trotter | #
|
1367 | aaae9bc0 | Guido Trotter | # This is done in an else clause because if the exception was thrown
|
1368 | aaae9bc0 | Guido Trotter | # it's the job of the one who actually deleted it.
|
1369 | aaae9bc0 | Guido Trotter | del self.__lockdict[lname] |
1370 | aaae9bc0 | Guido Trotter | # And let's remove it from our private list if we owned it.
|
1371 | aaae9bc0 | Guido Trotter | if self._is_owned(): |
1372 | b2dabfd6 | Guido Trotter | self._del_owned(name=lname)
|
1373 | aaae9bc0 | Guido Trotter | |
1374 | 3f404fc5 | Guido Trotter | return removed
|
1375 | aaae9bc0 | Guido Trotter | |
1376 | 7ee7c0c7 | Guido Trotter | |
1377 | 7ee7c0c7 | Guido Trotter | # Locking levels, must be acquired in increasing order.
|
1378 | 7ee7c0c7 | Guido Trotter | # Current rules are:
|
1379 | 7ee7c0c7 | Guido Trotter | # - at level LEVEL_CLUSTER resides the Big Ganeti Lock (BGL) which must be
|
1380 | 7ee7c0c7 | Guido Trotter | # acquired before performing any operation, either in shared or in exclusive
|
1381 | 7ee7c0c7 | Guido Trotter | # mode. acquiring the BGL in exclusive mode is discouraged and should be
|
1382 | 7ee7c0c7 | Guido Trotter | # avoided.
|
1383 | 7ee7c0c7 | Guido Trotter | # - at levels LEVEL_NODE and LEVEL_INSTANCE reside node and instance locks.
|
1384 | 7ee7c0c7 | Guido Trotter | # If you need more than one node, or more than one instance, acquire them at
|
1385 | 7ee7c0c7 | Guido Trotter | # the same time.
|
1386 | 7ee7c0c7 | Guido Trotter | LEVEL_CLUSTER = 0
|
1387 | 04e1bfaf | Guido Trotter | LEVEL_INSTANCE = 1
|
1388 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP = 2
|
1389 | 819ca990 | Guido Trotter | LEVEL_NODE = 3
|
1390 | 7ee7c0c7 | Guido Trotter | |
1391 | 7ee7c0c7 | Guido Trotter | LEVELS = [LEVEL_CLUSTER, |
1392 | 04e1bfaf | Guido Trotter | LEVEL_INSTANCE, |
1393 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP, |
1394 | 04e1bfaf | Guido Trotter | LEVEL_NODE] |
1395 | 7ee7c0c7 | Guido Trotter | |
1396 | 7ee7c0c7 | Guido Trotter | # Lock levels which are modifiable
|
1397 | 819ca990 | Guido Trotter | LEVELS_MOD = [LEVEL_NODE, LEVEL_NODEGROUP, LEVEL_INSTANCE] |
1398 | 7ee7c0c7 | Guido Trotter | |
1399 | ea205dbc | Michael Hanselmann | LEVEL_NAMES = { |
1400 | ea205dbc | Michael Hanselmann | LEVEL_CLUSTER: "cluster",
|
1401 | ea205dbc | Michael Hanselmann | LEVEL_INSTANCE: "instance",
|
1402 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP: "nodegroup",
|
1403 | ea205dbc | Michael Hanselmann | LEVEL_NODE: "node",
|
1404 | ea205dbc | Michael Hanselmann | } |
1405 | ea205dbc | Michael Hanselmann | |
1406 | 08a6c581 | Guido Trotter | # Constant for the big ganeti lock
|
1407 | 7ee7c0c7 | Guido Trotter | BGL = 'BGL'
|
1408 | 7ee7c0c7 | Guido Trotter | |
1409 | 7ee7c0c7 | Guido Trotter | |
1410 | 7ee7c0c7 | Guido Trotter | class GanetiLockManager: |
1411 | 7ee7c0c7 | Guido Trotter | """The Ganeti Locking Library
|
1412 | 7ee7c0c7 | Guido Trotter |
|
1413 | 5bbd3f7f | Michael Hanselmann | The purpose of this small library is to manage locking for ganeti clusters
|
1414 | 7ee7c0c7 | Guido Trotter | in a central place, while at the same time doing dynamic checks against
|
1415 | 7ee7c0c7 | Guido Trotter | possible deadlocks. It will also make it easier to transition to a different
|
1416 | 7ee7c0c7 | Guido Trotter | lock type should we migrate away from python threads.
|
1417 | 7ee7c0c7 | Guido Trotter |
|
1418 | 7ee7c0c7 | Guido Trotter | """
|
1419 | 7ee7c0c7 | Guido Trotter | _instance = None
|
1420 | 7ee7c0c7 | Guido Trotter | |
1421 | 819ca990 | Guido Trotter | def __init__(self, nodes, nodegroups, instances): |
1422 | 7ee7c0c7 | Guido Trotter | """Constructs a new GanetiLockManager object.
|
1423 | 7ee7c0c7 | Guido Trotter |
|
1424 | 4e07ec8c | Guido Trotter | There should be only a GanetiLockManager object at any time, so this
|
1425 | 4e07ec8c | Guido Trotter | function raises an error if this is not the case.
|
1426 | 7ee7c0c7 | Guido Trotter |
|
1427 | c41eea6e | Iustin Pop | @param nodes: list of node names
|
1428 | 819ca990 | Guido Trotter | @param nodegroups: list of nodegroup uuids
|
1429 | c41eea6e | Iustin Pop | @param instances: list of instance names
|
1430 | 7ee7c0c7 | Guido Trotter |
|
1431 | 7ee7c0c7 | Guido Trotter | """
|
1432 | c41eea6e | Iustin Pop | assert self.__class__._instance is None, \ |
1433 | c41eea6e | Iustin Pop | "double GanetiLockManager instance"
|
1434 | c41eea6e | Iustin Pop | |
1435 | 7ee7c0c7 | Guido Trotter | self.__class__._instance = self |
1436 | 7ee7c0c7 | Guido Trotter | |
1437 | 19b9ba9a | Michael Hanselmann | self._monitor = LockMonitor()
|
1438 | 19b9ba9a | Michael Hanselmann | |
1439 | 7ee7c0c7 | Guido Trotter | # The keyring contains all the locks, at their level and in the correct
|
1440 | 7ee7c0c7 | Guido Trotter | # locking order.
|
1441 | 7ee7c0c7 | Guido Trotter | self.__keyring = {
|
1442 | 19b9ba9a | Michael Hanselmann | LEVEL_CLUSTER: LockSet([BGL], "BGL", monitor=self._monitor), |
1443 | 19b9ba9a | Michael Hanselmann | LEVEL_NODE: LockSet(nodes, "nodes", monitor=self._monitor), |
1444 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP: LockSet(nodegroups, "nodegroups", monitor=self._monitor), |
1445 | 19b9ba9a | Michael Hanselmann | LEVEL_INSTANCE: LockSet(instances, "instances",
|
1446 | 19b9ba9a | Michael Hanselmann | monitor=self._monitor),
|
1447 | 19b9ba9a | Michael Hanselmann | } |
1448 | 19b9ba9a | Michael Hanselmann | |
1449 | 24d16f76 | Michael Hanselmann | def QueryLocks(self, fields): |
1450 | 19b9ba9a | Michael Hanselmann | """Queries information from all locks.
|
1451 | 19b9ba9a | Michael Hanselmann |
|
1452 | 19b9ba9a | Michael Hanselmann | See L{LockMonitor.QueryLocks}.
|
1453 | 19b9ba9a | Michael Hanselmann |
|
1454 | 19b9ba9a | Michael Hanselmann | """
|
1455 | 24d16f76 | Michael Hanselmann | return self._monitor.QueryLocks(fields) |
1456 | 24d16f76 | Michael Hanselmann | |
1457 | 24d16f76 | Michael Hanselmann | def OldStyleQueryLocks(self, fields): |
1458 | 24d16f76 | Michael Hanselmann | """Queries information from all locks, returning old-style data.
|
1459 | 24d16f76 | Michael Hanselmann |
|
1460 | 24d16f76 | Michael Hanselmann | See L{LockMonitor.OldStyleQueryLocks}.
|
1461 | 24d16f76 | Michael Hanselmann |
|
1462 | 24d16f76 | Michael Hanselmann | """
|
1463 | 24d16f76 | Michael Hanselmann | return self._monitor.OldStyleQueryLocks(fields) |
1464 | 7ee7c0c7 | Guido Trotter | |
1465 | 7ee7c0c7 | Guido Trotter | def _names(self, level): |
1466 | 7ee7c0c7 | Guido Trotter | """List the lock names at the given level.
|
1467 | 7ee7c0c7 | Guido Trotter |
|
1468 | c41eea6e | Iustin Pop | This can be used for debugging/testing purposes.
|
1469 | c41eea6e | Iustin Pop |
|
1470 | c41eea6e | Iustin Pop | @param level: the level whose list of locks to get
|
1471 | 7ee7c0c7 | Guido Trotter |
|
1472 | 7ee7c0c7 | Guido Trotter | """
|
1473 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1474 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level]._names() |
1475 | 7ee7c0c7 | Guido Trotter | |
1476 | 7ee7c0c7 | Guido Trotter | def _is_owned(self, level): |
1477 | 7ee7c0c7 | Guido Trotter | """Check whether we are owning locks at the given level
|
1478 | 7ee7c0c7 | Guido Trotter |
|
1479 | 7ee7c0c7 | Guido Trotter | """
|
1480 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level]._is_owned() |
1481 | 7ee7c0c7 | Guido Trotter | |
1482 | d4f4b3e7 | Guido Trotter | is_owned = _is_owned |
1483 | d4f4b3e7 | Guido Trotter | |
1484 | 7ee7c0c7 | Guido Trotter | def _list_owned(self, level): |
1485 | 7ee7c0c7 | Guido Trotter | """Get the set of owned locks at the given level
|
1486 | 7ee7c0c7 | Guido Trotter |
|
1487 | 7ee7c0c7 | Guido Trotter | """
|
1488 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level]._list_owned() |
1489 | 7ee7c0c7 | Guido Trotter | |
1490 | 07cba1bc | Michael Hanselmann | list_owned = _list_owned |
1491 | 07cba1bc | Michael Hanselmann | |
1492 | 7ee7c0c7 | Guido Trotter | def _upper_owned(self, level): |
1493 | 7ee7c0c7 | Guido Trotter | """Check that we don't own any lock at a level greater than the given one.
|
1494 | 7ee7c0c7 | Guido Trotter |
|
1495 | 7ee7c0c7 | Guido Trotter | """
|
1496 | 7ee7c0c7 | Guido Trotter | # This way of checking only works if LEVELS[i] = i, which we check for in
|
1497 | 7ee7c0c7 | Guido Trotter | # the test cases.
|
1498 | cea881e5 | Michael Hanselmann | return compat.any((self._is_owned(l) for l in LEVELS[level + 1:])) |
1499 | 7ee7c0c7 | Guido Trotter | |
1500 | fe267188 | Iustin Pop | def _BGL_owned(self): # pylint: disable-msg=C0103 |
1501 | 7ee7c0c7 | Guido Trotter | """Check if the current thread owns the BGL.
|
1502 | 7ee7c0c7 | Guido Trotter |
|
1503 | 7ee7c0c7 | Guido Trotter | Both an exclusive or a shared acquisition work.
|
1504 | 7ee7c0c7 | Guido Trotter |
|
1505 | 7ee7c0c7 | Guido Trotter | """
|
1506 | 7ee7c0c7 | Guido Trotter | return BGL in self.__keyring[LEVEL_CLUSTER]._list_owned() |
1507 | 7ee7c0c7 | Guido Trotter | |
1508 | c70d2d9b | Iustin Pop | @staticmethod
|
1509 | c70d2d9b | Iustin Pop | def _contains_BGL(level, names): # pylint: disable-msg=C0103 |
1510 | c41eea6e | Iustin Pop | """Check if the level contains the BGL.
|
1511 | c41eea6e | Iustin Pop |
|
1512 | c41eea6e | Iustin Pop | Check if acting on the given level and set of names will change
|
1513 | c41eea6e | Iustin Pop | the status of the Big Ganeti Lock.
|
1514 | 7ee7c0c7 | Guido Trotter |
|
1515 | 7ee7c0c7 | Guido Trotter | """
|
1516 | 7ee7c0c7 | Guido Trotter | return level == LEVEL_CLUSTER and (names is None or BGL in names) |
1517 | 7ee7c0c7 | Guido Trotter | |
1518 | b30d95b6 | Michael Hanselmann | def acquire(self, level, names, timeout=None, shared=0, priority=None): |
1519 | 7ee7c0c7 | Guido Trotter | """Acquire a set of resource locks, at the same level.
|
1520 | 7ee7c0c7 | Guido Trotter |
|
1521 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS
|
1522 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be acquired
|
1523 | ec44d893 | Guido Trotter | @type names: list of strings (or string)
|
1524 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be acquired
|
1525 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1526 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1527 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default
|
1528 | c41eea6e | Iustin Pop | an exclusive lock will be acquired
|
1529 | 5e0a6daf | Michael Hanselmann | @type timeout: float
|
1530 | 5e0a6daf | Michael Hanselmann | @param timeout: Maximum time to acquire all locks
|
1531 | b30d95b6 | Michael Hanselmann | @type priority: integer
|
1532 | b30d95b6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
1533 | 7ee7c0c7 | Guido Trotter |
|
1534 | 7ee7c0c7 | Guido Trotter | """
|
1535 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1536 | 7ee7c0c7 | Guido Trotter | |
1537 | 7ee7c0c7 | Guido Trotter | # Check that we are either acquiring the Big Ganeti Lock or we already own
|
1538 | 7ee7c0c7 | Guido Trotter | # it. Some "legacy" opcodes need to be sure they are run non-concurrently
|
1539 | 7ee7c0c7 | Guido Trotter | # so even if we've migrated we need to at least share the BGL to be
|
1540 | 7ee7c0c7 | Guido Trotter | # compatible with them. Of course if we own the BGL exclusively there's no
|
1541 | 7ee7c0c7 | Guido Trotter | # point in acquiring any other lock, unless perhaps we are half way through
|
1542 | 7ee7c0c7 | Guido Trotter | # the migration of the current opcode.
|
1543 | 7ee7c0c7 | Guido Trotter | assert (self._contains_BGL(level, names) or self._BGL_owned()), ( |
1544 | 7ee7c0c7 | Guido Trotter | "You must own the Big Ganeti Lock before acquiring any other")
|
1545 | 7ee7c0c7 | Guido Trotter | |
1546 | 7ee7c0c7 | Guido Trotter | # Check we don't own locks at the same or upper levels.
|
1547 | 21a6c826 | Guido Trotter | assert not self._upper_owned(level), ("Cannot acquire locks at a level" |
1548 | 7ee7c0c7 | Guido Trotter | " while owning some at a greater one")
|
1549 | 7ee7c0c7 | Guido Trotter | |
1550 | 7ee7c0c7 | Guido Trotter | # Acquire the locks in the set.
|
1551 | b30d95b6 | Michael Hanselmann | return self.__keyring[level].acquire(names, shared=shared, timeout=timeout, |
1552 | b30d95b6 | Michael Hanselmann | priority=priority) |
1553 | 7ee7c0c7 | Guido Trotter | |
1554 | 3dbe3ddf | Michael Hanselmann | def downgrade(self, level, names=None): |
1555 | 3dbe3ddf | Michael Hanselmann | """Downgrade a set of resource locks from exclusive to shared mode.
|
1556 | 3dbe3ddf | Michael Hanselmann |
|
1557 | 3dbe3ddf | Michael Hanselmann | You must have acquired the locks in exclusive mode.
|
1558 | 3dbe3ddf | Michael Hanselmann |
|
1559 | 3dbe3ddf | Michael Hanselmann | @type level: member of locking.LEVELS
|
1560 | 3dbe3ddf | Michael Hanselmann | @param level: the level at which the locks shall be downgraded
|
1561 | 3dbe3ddf | Michael Hanselmann | @type names: list of strings, or None
|
1562 | 3dbe3ddf | Michael Hanselmann | @param names: the names of the locks which shall be downgraded
|
1563 | 3dbe3ddf | Michael Hanselmann | (defaults to all the locks acquired at the level)
|
1564 | 3dbe3ddf | Michael Hanselmann |
|
1565 | 3dbe3ddf | Michael Hanselmann | """
|
1566 | 3dbe3ddf | Michael Hanselmann | assert level in LEVELS, "Invalid locking level %s" % level |
1567 | 3dbe3ddf | Michael Hanselmann | |
1568 | 3dbe3ddf | Michael Hanselmann | return self.__keyring[level].downgrade(names=names) |
1569 | 3dbe3ddf | Michael Hanselmann | |
1570 | 7ee7c0c7 | Guido Trotter | def release(self, level, names=None): |
1571 | 7ee7c0c7 | Guido Trotter | """Release a set of resource locks, at the same level.
|
1572 | 7ee7c0c7 | Guido Trotter |
|
1573 | c41eea6e | Iustin Pop | You must have acquired the locks, either in shared or in exclusive
|
1574 | c41eea6e | Iustin Pop | mode, before releasing them.
|
1575 | 7ee7c0c7 | Guido Trotter |
|
1576 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS
|
1577 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be released
|
1578 | ec44d893 | Guido Trotter | @type names: list of strings, or None
|
1579 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be released
|
1580 | c41eea6e | Iustin Pop | (defaults to all the locks acquired at that level)
|
1581 | 7ee7c0c7 | Guido Trotter |
|
1582 | 7ee7c0c7 | Guido Trotter | """
|
1583 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1584 | 7ee7c0c7 | Guido Trotter | assert (not self._contains_BGL(level, names) or |
1585 | 7ee7c0c7 | Guido Trotter | not self._upper_owned(LEVEL_CLUSTER)), ( |
1586 | 7ee7c0c7 | Guido Trotter | "Cannot release the Big Ganeti Lock while holding something"
|
1587 | e4335b5b | Michael Hanselmann | " at upper levels (%r)" %
|
1588 | 1f864b60 | Iustin Pop | (utils.CommaJoin(["%s=%r" % (LEVEL_NAMES[i], self._list_owned(i)) |
1589 | 1f864b60 | Iustin Pop | for i in self.__keyring.keys()]), )) |
1590 | 7ee7c0c7 | Guido Trotter | |
1591 | 7ee7c0c7 | Guido Trotter | # Release will complain if we don't own the locks already
|
1592 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level].release(names) |
1593 | 7ee7c0c7 | Guido Trotter | |
1594 | 7ee7c0c7 | Guido Trotter | def add(self, level, names, acquired=0, shared=0): |
1595 | 7ee7c0c7 | Guido Trotter | """Add locks at the specified level.
|
1596 | 7ee7c0c7 | Guido Trotter |
|
1597 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS_MOD
|
1598 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be added
|
1599 | ec44d893 | Guido Trotter | @type names: list of strings
|
1600 | c41eea6e | Iustin Pop | @param names: names of the locks to acquire
|
1601 | ec44d893 | Guido Trotter | @type acquired: integer (0/1) used as a boolean
|
1602 | c41eea6e | Iustin Pop | @param acquired: whether to acquire the newly added locks
|
1603 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1604 | c41eea6e | Iustin Pop | @param shared: whether the acquisition will be shared
|
1605 | c41eea6e | Iustin Pop |
|
1606 | 7ee7c0c7 | Guido Trotter | """
|
1607 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS_MOD, "Invalid or immutable level %s" % level |
1608 | 7ee7c0c7 | Guido Trotter | assert self._BGL_owned(), ("You must own the BGL before performing other" |
1609 | 7ee7c0c7 | Guido Trotter | " operations")
|
1610 | 7ee7c0c7 | Guido Trotter | assert not self._upper_owned(level), ("Cannot add locks at a level" |
1611 | 7ee7c0c7 | Guido Trotter | " while owning some at a greater one")
|
1612 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level].add(names, acquired=acquired, shared=shared) |
1613 | 7ee7c0c7 | Guido Trotter | |
1614 | 5e0a6daf | Michael Hanselmann | def remove(self, level, names): |
1615 | 7ee7c0c7 | Guido Trotter | """Remove locks from the specified level.
|
1616 | 7ee7c0c7 | Guido Trotter |
|
1617 | c41eea6e | Iustin Pop | You must either already own the locks you are trying to remove
|
1618 | c41eea6e | Iustin Pop | exclusively or not own any lock at an upper level.
|
1619 | 7ee7c0c7 | Guido Trotter |
|
1620 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS_MOD
|
1621 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be removed
|
1622 | ec44d893 | Guido Trotter | @type names: list of strings
|
1623 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be removed
|
1624 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1625 | 7ee7c0c7 | Guido Trotter |
|
1626 | 7ee7c0c7 | Guido Trotter | """
|
1627 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS_MOD, "Invalid or immutable level %s" % level |
1628 | 7ee7c0c7 | Guido Trotter | assert self._BGL_owned(), ("You must own the BGL before performing other" |
1629 | 7ee7c0c7 | Guido Trotter | " operations")
|
1630 | f12eadb3 | Iustin Pop | # Check we either own the level or don't own anything from here
|
1631 | f12eadb3 | Iustin Pop | # up. LockSet.remove() will check the case in which we don't own
|
1632 | f12eadb3 | Iustin Pop | # all the needed resources, or we have a shared ownership.
|
1633 | 7ee7c0c7 | Guido Trotter | assert self._is_owned(level) or not self._upper_owned(level), ( |
1634 | 7ee7c0c7 | Guido Trotter | "Cannot remove locks at a level while not owning it or"
|
1635 | 7ee7c0c7 | Guido Trotter | " owning some at a greater one")
|
1636 | 5e0a6daf | Michael Hanselmann | return self.__keyring[level].remove(names) |
1637 | 19b9ba9a | Michael Hanselmann | |
1638 | 19b9ba9a | Michael Hanselmann | |
1639 | e4e35357 | Michael Hanselmann | def _MonitorSortKey((num, item)): |
1640 | e4e35357 | Michael Hanselmann | """Sorting key function.
|
1641 | e4e35357 | Michael Hanselmann |
|
1642 | e4e35357 | Michael Hanselmann | Sort by name, then by incoming order.
|
1643 | e4e35357 | Michael Hanselmann |
|
1644 | e4e35357 | Michael Hanselmann | """
|
1645 | e4e35357 | Michael Hanselmann | (name, _, _, _) = item |
1646 | e4e35357 | Michael Hanselmann | |
1647 | e4e35357 | Michael Hanselmann | return (utils.NiceSortKey(name), num)
|
1648 | e4e35357 | Michael Hanselmann | |
1649 | e4e35357 | Michael Hanselmann | |
1650 | 19b9ba9a | Michael Hanselmann | class LockMonitor(object): |
1651 | 19b9ba9a | Michael Hanselmann | _LOCK_ATTR = "_lock"
|
1652 | 19b9ba9a | Michael Hanselmann | |
1653 | 19b9ba9a | Michael Hanselmann | def __init__(self): |
1654 | 19b9ba9a | Michael Hanselmann | """Initializes this class.
|
1655 | 19b9ba9a | Michael Hanselmann |
|
1656 | 19b9ba9a | Michael Hanselmann | """
|
1657 | 19b9ba9a | Michael Hanselmann | self._lock = SharedLock("LockMonitor") |
1658 | 19b9ba9a | Michael Hanselmann | |
1659 | e4e35357 | Michael Hanselmann | # Counter for stable sorting
|
1660 | e4e35357 | Michael Hanselmann | self._counter = itertools.count(0) |
1661 | e4e35357 | Michael Hanselmann | |
1662 | 19b9ba9a | Michael Hanselmann | # Tracked locks. Weak references are used to avoid issues with circular
|
1663 | 19b9ba9a | Michael Hanselmann | # references and deletion.
|
1664 | 19b9ba9a | Michael Hanselmann | self._locks = weakref.WeakKeyDictionary()
|
1665 | 19b9ba9a | Michael Hanselmann | |
1666 | 19b9ba9a | Michael Hanselmann | @ssynchronized(_LOCK_ATTR)
|
1667 | 19b9ba9a | Michael Hanselmann | def RegisterLock(self, lock): |
1668 | 19b9ba9a | Michael Hanselmann | """Registers a new lock.
|
1669 | 19b9ba9a | Michael Hanselmann |
|
1670 | 19b9ba9a | Michael Hanselmann | """
|
1671 | 19b9ba9a | Michael Hanselmann | logging.debug("Registering lock %s", lock.name)
|
1672 | 19b9ba9a | Michael Hanselmann | assert lock not in self._locks, "Duplicate lock registration" |
1673 | e4e35357 | Michael Hanselmann | |
1674 | e4e35357 | Michael Hanselmann | # There used to be a check for duplicate names here. As it turned out, when
|
1675 | e4e35357 | Michael Hanselmann | # a lock is re-created with the same name in a very short timeframe, the
|
1676 | e4e35357 | Michael Hanselmann | # previous instance might not yet be removed from the weakref dictionary.
|
1677 | e4e35357 | Michael Hanselmann | # By keeping track of the order of incoming registrations, a stable sort
|
1678 | e4e35357 | Michael Hanselmann | # ordering can still be guaranteed.
|
1679 | e4e35357 | Michael Hanselmann | |
1680 | e4e35357 | Michael Hanselmann | self._locks[lock] = self._counter.next() |
1681 | 19b9ba9a | Michael Hanselmann | |
1682 | 19b9ba9a | Michael Hanselmann | @ssynchronized(_LOCK_ATTR)
|
1683 | 24d16f76 | Michael Hanselmann | def _GetLockInfo(self, requested): |
1684 | 19b9ba9a | Michael Hanselmann | """Get information from all locks while the monitor lock is held.
|
1685 | 19b9ba9a | Michael Hanselmann |
|
1686 | 19b9ba9a | Michael Hanselmann | """
|
1687 | e4e35357 | Michael Hanselmann | return [(num, lock.GetInfo(requested)) for lock, num in self._locks.items()] |
1688 | 19b9ba9a | Michael Hanselmann | |
1689 | 24d16f76 | Michael Hanselmann | def _Query(self, fields): |
1690 | 24d16f76 | Michael Hanselmann | """Queries information from all locks.
|
1691 | 19b9ba9a | Michael Hanselmann |
|
1692 | 24d16f76 | Michael Hanselmann | @type fields: list of strings
|
1693 | 24d16f76 | Michael Hanselmann | @param fields: List of fields to return
|
1694 | 24d16f76 | Michael Hanselmann |
|
1695 | 24d16f76 | Michael Hanselmann | """
|
1696 | 24d16f76 | Michael Hanselmann | qobj = query.Query(query.LOCK_FIELDS, fields) |
1697 | 24d16f76 | Michael Hanselmann | |
1698 | e4e35357 | Michael Hanselmann | # Get all data with internal lock held and then sort by name and incoming
|
1699 | e4e35357 | Michael Hanselmann | # order
|
1700 | e4e35357 | Michael Hanselmann | lockinfo = sorted(self._GetLockInfo(qobj.RequestedData()), |
1701 | e4e35357 | Michael Hanselmann | key=_MonitorSortKey) |
1702 | 24d16f76 | Michael Hanselmann | |
1703 | e4e35357 | Michael Hanselmann | # Extract lock information and build query data
|
1704 | e4e35357 | Michael Hanselmann | return (qobj, query.LockQueryData(map(operator.itemgetter(1), lockinfo))) |
1705 | 19b9ba9a | Michael Hanselmann | |
1706 | 24d16f76 | Michael Hanselmann | def QueryLocks(self, fields): |
1707 | 19b9ba9a | Michael Hanselmann | """Queries information from all locks.
|
1708 | 19b9ba9a | Michael Hanselmann |
|
1709 | 19b9ba9a | Michael Hanselmann | @type fields: list of strings
|
1710 | 19b9ba9a | Michael Hanselmann | @param fields: List of fields to return
|
1711 | 19b9ba9a | Michael Hanselmann |
|
1712 | 19b9ba9a | Michael Hanselmann | """
|
1713 | 24d16f76 | Michael Hanselmann | (qobj, ctx) = self._Query(fields)
|
1714 | 19b9ba9a | Michael Hanselmann | |
1715 | 24d16f76 | Michael Hanselmann | # Prepare query response
|
1716 | 24d16f76 | Michael Hanselmann | return query.GetQueryResponse(qobj, ctx)
|
1717 | 24d16f76 | Michael Hanselmann | |
1718 | 24d16f76 | Michael Hanselmann | def OldStyleQueryLocks(self, fields): |
1719 | 24d16f76 | Michael Hanselmann | """Queries information from all locks, returning old-style data.
|
1720 | 24d16f76 | Michael Hanselmann |
|
1721 | 24d16f76 | Michael Hanselmann | @type fields: list of strings
|
1722 | 24d16f76 | Michael Hanselmann | @param fields: List of fields to return
|
1723 | 24d16f76 | Michael Hanselmann |
|
1724 | 24d16f76 | Michael Hanselmann | """
|
1725 | 24d16f76 | Michael Hanselmann | (qobj, ctx) = self._Query(fields)
|
1726 | 19b9ba9a | Michael Hanselmann | |
1727 | 24d16f76 | Michael Hanselmann | return qobj.OldStyleQuery(ctx) |