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1 | 162c1c1f | Guido Trotter | #
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2 | 162c1c1f | Guido Trotter | #
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3 | 162c1c1f | Guido Trotter | |
4 | 5ae4945a | Iustin Pop | # Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Google Inc.
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5 | 162c1c1f | Guido Trotter | #
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6 | 162c1c1f | Guido Trotter | # This program is free software; you can redistribute it and/or modify
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7 | 162c1c1f | Guido Trotter | # it under the terms of the GNU General Public License as published by
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8 | 162c1c1f | Guido Trotter | # the Free Software Foundation; either version 2 of the License, or
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9 | 162c1c1f | Guido Trotter | # (at your option) any later version.
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10 | 162c1c1f | Guido Trotter | #
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11 | 162c1c1f | Guido Trotter | # This program is distributed in the hope that it will be useful, but
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12 | 162c1c1f | Guido Trotter | # WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | 162c1c1f | Guido Trotter | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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14 | 162c1c1f | Guido Trotter | # General Public License for more details.
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15 | 162c1c1f | Guido Trotter | #
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16 | 162c1c1f | Guido Trotter | # You should have received a copy of the GNU General Public License
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17 | 162c1c1f | Guido Trotter | # along with this program; if not, write to the Free Software
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18 | 162c1c1f | Guido Trotter | # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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19 | 162c1c1f | Guido Trotter | # 02110-1301, USA.
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20 | 162c1c1f | Guido Trotter | |
21 | 162c1c1f | Guido Trotter | """Module implementing the Ganeti locking code."""
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22 | 162c1c1f | Guido Trotter | |
23 | b459a848 | Andrea Spadaccini | # pylint: disable=W0212
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24 | c70d2d9b | Iustin Pop | |
25 | c70d2d9b | Iustin Pop | # W0212 since e.g. LockSet methods use (a lot) the internals of
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26 | c70d2d9b | Iustin Pop | # SharedLock
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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 | e4e35357 | Michael Hanselmann | import itertools |
36 | 8d7d8b57 | Michael Hanselmann | import time |
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"
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45 | c31825f7 | Michael Hanselmann | _SHARED_TEXT = "shared"
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46 | 24d16f76 | Michael Hanselmann | _DELETED_TEXT = "deleted"
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47 | c31825f7 | Michael Hanselmann | |
48 | 887c7aa6 | Michael Hanselmann | _DEFAULT_PRIORITY = 0
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49 | 887c7aa6 | Michael Hanselmann | |
50 | 03c5291c | Michael Hanselmann | #: Minimum timeout required to consider scheduling a pending acquisition
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51 | 03c5291c | Michael Hanselmann | #: (seconds)
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52 | 03c5291c | Michael Hanselmann | _LOCK_ACQUIRE_MIN_TIMEOUT = (1.0 / 1000) |
53 | 03c5291c | Michael Hanselmann | |
54 | c31825f7 | Michael Hanselmann | |
55 | dbb11e8b | Guido Trotter | def ssynchronized(mylock, shared=0): |
56 | 42a999d1 | Guido Trotter | """Shared Synchronization decorator.
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57 | 42a999d1 | Guido Trotter |
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58 | 42a999d1 | Guido Trotter | Calls the function holding the given lock, either in exclusive or shared
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59 | 42a999d1 | Guido Trotter | mode. It requires the passed lock to be a SharedLock (or support its
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60 | 42a999d1 | Guido Trotter | semantics).
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61 | 42a999d1 | Guido Trotter |
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62 | dbb11e8b | Guido Trotter | @type mylock: lockable object or string
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63 | dbb11e8b | Guido Trotter | @param mylock: lock to acquire or class member name of the lock to acquire
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64 | dbb11e8b | Guido Trotter |
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65 | 42a999d1 | Guido Trotter | """
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66 | 42a999d1 | Guido Trotter | def wrap(fn): |
67 | 42a999d1 | Guido Trotter | def sync_function(*args, **kwargs): |
68 | dbb11e8b | Guido Trotter | if isinstance(mylock, basestring): |
69 | dbb11e8b | Guido Trotter | assert args, "cannot ssynchronize on non-class method: self not found" |
70 | dbb11e8b | Guido Trotter | # args[0] is "self"
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71 | dbb11e8b | Guido Trotter | lock = getattr(args[0], mylock) |
72 | dbb11e8b | Guido Trotter | else:
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73 | dbb11e8b | Guido Trotter | lock = mylock |
74 | 42a999d1 | Guido Trotter | lock.acquire(shared=shared) |
75 | 42a999d1 | Guido Trotter | try:
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76 | 42a999d1 | Guido Trotter | return fn(*args, **kwargs)
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77 | 42a999d1 | Guido Trotter | finally:
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78 | 42a999d1 | Guido Trotter | lock.release() |
79 | 42a999d1 | Guido Trotter | return sync_function
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80 | 42a999d1 | Guido Trotter | return wrap
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81 | 42a999d1 | Guido Trotter | |
82 | 42a999d1 | Guido Trotter | |
83 | 34cb5617 | Guido Trotter | class _SingleNotifyPipeConditionWaiter(object): |
84 | 34cb5617 | Guido Trotter | """Helper class for SingleNotifyPipeCondition
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85 | d76167a5 | Michael Hanselmann |
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86 | d76167a5 | Michael Hanselmann | """
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87 | d76167a5 | Michael Hanselmann | __slots__ = [ |
88 | d76167a5 | Michael Hanselmann | "_fd",
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89 | d76167a5 | Michael Hanselmann | "_poller",
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90 | d76167a5 | Michael Hanselmann | ] |
91 | d76167a5 | Michael Hanselmann | |
92 | 34cb5617 | Guido Trotter | def __init__(self, poller, fd): |
93 | 34cb5617 | Guido Trotter | """Constructor for _SingleNotifyPipeConditionWaiter
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94 | d76167a5 | Michael Hanselmann |
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95 | d76167a5 | Michael Hanselmann | @type poller: select.poll
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96 | d76167a5 | Michael Hanselmann | @param poller: Poller object
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97 | d76167a5 | Michael Hanselmann | @type fd: int
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98 | d76167a5 | Michael Hanselmann | @param fd: File descriptor to wait for
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99 | d76167a5 | Michael Hanselmann |
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100 | d76167a5 | Michael Hanselmann | """
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101 | d76167a5 | Michael Hanselmann | object.__init__(self) |
102 | d76167a5 | Michael Hanselmann | self._poller = poller
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103 | d76167a5 | Michael Hanselmann | self._fd = fd
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104 | d76167a5 | Michael Hanselmann | |
105 | d76167a5 | Michael Hanselmann | def __call__(self, timeout): |
106 | d76167a5 | Michael Hanselmann | """Wait for something to happen on the pipe.
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107 | d76167a5 | Michael Hanselmann |
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108 | d76167a5 | Michael Hanselmann | @type timeout: float or None
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109 | d76167a5 | Michael Hanselmann | @param timeout: Timeout for waiting (can be None)
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110 | d76167a5 | Michael Hanselmann |
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111 | d76167a5 | Michael Hanselmann | """
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112 | 557838c1 | Renรฉ Nussbaumer | running_timeout = utils.RunningTimeout(timeout, True)
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113 | f4e673fb | Michael Hanselmann | |
114 | f4e673fb | Michael Hanselmann | while True: |
115 | f4e673fb | Michael Hanselmann | remaining_time = running_timeout.Remaining() |
116 | f4e673fb | Michael Hanselmann | |
117 | b44b0141 | Michael Hanselmann | if remaining_time is not None: |
118 | b44b0141 | Michael Hanselmann | if remaining_time < 0.0: |
119 | b44b0141 | Michael Hanselmann | break
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120 | d76167a5 | Michael Hanselmann | |
121 | 413b7472 | Michael Hanselmann | # Our calculation uses seconds, poll() wants milliseconds
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122 | b44b0141 | Michael Hanselmann | remaining_time *= 1000
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123 | d76167a5 | Michael Hanselmann | |
124 | d76167a5 | Michael Hanselmann | try:
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125 | d76167a5 | Michael Hanselmann | result = self._poller.poll(remaining_time)
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126 | d76167a5 | Michael Hanselmann | except EnvironmentError, err: |
127 | d76167a5 | Michael Hanselmann | if err.errno != errno.EINTR:
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128 | d76167a5 | Michael Hanselmann | raise
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129 | d76167a5 | Michael Hanselmann | result = None
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130 | d76167a5 | Michael Hanselmann | |
131 | d76167a5 | Michael Hanselmann | # Check whether we were notified
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132 | d76167a5 | Michael Hanselmann | if result and result[0][0] == self._fd: |
133 | d76167a5 | Michael Hanselmann | break
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134 | d76167a5 | Michael Hanselmann | |
135 | d76167a5 | Michael Hanselmann | |
136 | 2419060d | Guido Trotter | class _BaseCondition(object): |
137 | 2419060d | Guido Trotter | """Base class containing common code for conditions.
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138 | 2419060d | Guido Trotter |
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139 | 2419060d | Guido Trotter | Some of this code is taken from python's threading module.
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140 | 2419060d | Guido Trotter |
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141 | 2419060d | Guido Trotter | """
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142 | 2419060d | Guido Trotter | __slots__ = [ |
143 | 2419060d | Guido Trotter | "_lock",
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144 | 2419060d | Guido Trotter | "acquire",
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145 | 2419060d | Guido Trotter | "release",
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146 | 7f890059 | Guido Trotter | "_is_owned",
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147 | 7f890059 | Guido Trotter | "_acquire_restore",
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148 | 7f890059 | Guido Trotter | "_release_save",
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149 | 2419060d | Guido Trotter | ] |
150 | 2419060d | Guido Trotter | |
151 | 2419060d | Guido Trotter | def __init__(self, lock): |
152 | 2419060d | Guido Trotter | """Constructor for _BaseCondition.
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153 | 2419060d | Guido Trotter |
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154 | 69b99987 | Michael Hanselmann | @type lock: threading.Lock
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155 | 2419060d | Guido Trotter | @param lock: condition base lock
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156 | 2419060d | Guido Trotter |
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157 | 2419060d | Guido Trotter | """
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158 | 2419060d | Guido Trotter | object.__init__(self) |
159 | 2419060d | Guido Trotter | |
160 | 7f890059 | Guido Trotter | try:
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161 | 7f890059 | Guido Trotter | self._release_save = lock._release_save
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162 | 7f890059 | Guido Trotter | except AttributeError: |
163 | 7f890059 | Guido Trotter | self._release_save = self._base_release_save |
164 | 7f890059 | Guido Trotter | try:
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165 | 7f890059 | Guido Trotter | self._acquire_restore = lock._acquire_restore
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166 | 7f890059 | Guido Trotter | except AttributeError: |
167 | 7f890059 | Guido Trotter | self._acquire_restore = self._base_acquire_restore |
168 | 7f890059 | Guido Trotter | try:
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169 | ee2b99e3 | Michael Hanselmann | self._is_owned = lock.is_owned
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170 | 7f890059 | Guido Trotter | except AttributeError: |
171 | 7f890059 | Guido Trotter | self._is_owned = self._base_is_owned |
172 | 2419060d | Guido Trotter | |
173 | 2419060d | Guido Trotter | self._lock = lock
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174 | 2419060d | Guido Trotter | |
175 | 2419060d | Guido Trotter | # Export the lock's acquire() and release() methods
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176 | 2419060d | Guido Trotter | self.acquire = lock.acquire
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177 | 2419060d | Guido Trotter | self.release = lock.release
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178 | 2419060d | Guido Trotter | |
179 | 7f890059 | Guido Trotter | def _base_is_owned(self): |
180 | 2419060d | Guido Trotter | """Check whether lock is owned by current thread.
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181 | 2419060d | Guido Trotter |
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182 | 2419060d | Guido Trotter | """
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183 | 2419060d | Guido Trotter | if self._lock.acquire(0): |
184 | 2419060d | Guido Trotter | self._lock.release()
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185 | 2419060d | Guido Trotter | return False |
186 | 2419060d | Guido Trotter | return True |
187 | 2419060d | Guido Trotter | |
188 | 7f890059 | Guido Trotter | def _base_release_save(self): |
189 | 7f890059 | Guido Trotter | self._lock.release()
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190 | 7f890059 | Guido Trotter | |
191 | 7f890059 | Guido Trotter | def _base_acquire_restore(self, _): |
192 | 7f890059 | Guido Trotter | self._lock.acquire()
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193 | 7f890059 | Guido Trotter | |
194 | 2419060d | Guido Trotter | def _check_owned(self): |
195 | 2419060d | Guido Trotter | """Raise an exception if the current thread doesn't own the lock.
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196 | 2419060d | Guido Trotter |
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197 | 2419060d | Guido Trotter | """
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198 | 2419060d | Guido Trotter | if not self._is_owned(): |
199 | 2419060d | Guido Trotter | raise RuntimeError("cannot work with un-aquired lock") |
200 | 2419060d | Guido Trotter | |
201 | 2419060d | Guido Trotter | |
202 | 34cb5617 | Guido Trotter | class SingleNotifyPipeCondition(_BaseCondition): |
203 | 34cb5617 | Guido Trotter | """Condition which can only be notified once.
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204 | d76167a5 | Michael Hanselmann |
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205 | 34cb5617 | Guido Trotter | This condition class uses pipes and poll, internally, to be able to wait for
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206 | 34cb5617 | Guido Trotter | notification with a timeout, without resorting to polling. It is almost
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207 | 34cb5617 | Guido Trotter | compatible with Python's threading.Condition, with the following differences:
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208 | 34cb5617 | Guido Trotter | - notifyAll can only be called once, and no wait can happen after that
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209 | 34cb5617 | Guido Trotter | - notify is not supported, only notifyAll
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210 | d76167a5 | Michael Hanselmann |
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211 | d76167a5 | Michael Hanselmann | """
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212 | 34cb5617 | Guido Trotter | |
213 | 154b9580 | Balazs Lecz | __slots__ = [ |
214 | d76167a5 | Michael Hanselmann | "_poller",
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215 | d76167a5 | Michael Hanselmann | "_read_fd",
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216 | d76167a5 | Michael Hanselmann | "_write_fd",
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217 | d76167a5 | Michael Hanselmann | "_nwaiters",
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218 | 34cb5617 | Guido Trotter | "_notified",
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219 | d76167a5 | Michael Hanselmann | ] |
220 | d76167a5 | Michael Hanselmann | |
221 | 34cb5617 | Guido Trotter | _waiter_class = _SingleNotifyPipeConditionWaiter |
222 | d76167a5 | Michael Hanselmann | |
223 | 34cb5617 | Guido Trotter | def __init__(self, lock): |
224 | 34cb5617 | Guido Trotter | """Constructor for SingleNotifyPipeCondition
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225 | d76167a5 | Michael Hanselmann |
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226 | d76167a5 | Michael Hanselmann | """
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227 | 34cb5617 | Guido Trotter | _BaseCondition.__init__(self, lock)
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228 | d76167a5 | Michael Hanselmann | self._nwaiters = 0 |
229 | 34cb5617 | Guido Trotter | self._notified = False |
230 | 34cb5617 | Guido Trotter | self._read_fd = None |
231 | 34cb5617 | Guido Trotter | self._write_fd = None |
232 | 34cb5617 | Guido Trotter | self._poller = None |
233 | d76167a5 | Michael Hanselmann | |
234 | 34cb5617 | Guido Trotter | def _check_unnotified(self): |
235 | 69b99987 | Michael Hanselmann | """Throws an exception if already notified.
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236 | 69b99987 | Michael Hanselmann |
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237 | 69b99987 | Michael Hanselmann | """
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238 | 34cb5617 | Guido Trotter | if self._notified: |
239 | 34cb5617 | Guido Trotter | raise RuntimeError("cannot use already notified condition") |
240 | d76167a5 | Michael Hanselmann | |
241 | 34cb5617 | Guido Trotter | def _Cleanup(self): |
242 | 34cb5617 | Guido Trotter | """Cleanup open file descriptors, if any.
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243 | d76167a5 | Michael Hanselmann |
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244 | d76167a5 | Michael Hanselmann | """
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245 | 34cb5617 | Guido Trotter | if self._read_fd is not None: |
246 | 34cb5617 | Guido Trotter | os.close(self._read_fd)
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247 | 34cb5617 | Guido Trotter | self._read_fd = None |
248 | d76167a5 | Michael Hanselmann | |
249 | 34cb5617 | Guido Trotter | if self._write_fd is not None: |
250 | 34cb5617 | Guido Trotter | os.close(self._write_fd)
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251 | 34cb5617 | Guido Trotter | self._write_fd = None |
252 | 34cb5617 | Guido Trotter | self._poller = None |
253 | d76167a5 | Michael Hanselmann | |
254 | 83f2d5f6 | Michael Hanselmann | def wait(self, timeout): |
255 | 34cb5617 | Guido Trotter | """Wait for a notification.
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256 | d76167a5 | Michael Hanselmann |
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257 | 34cb5617 | Guido Trotter | @type timeout: float or None
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258 | 34cb5617 | Guido Trotter | @param timeout: Waiting timeout (can be None)
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259 | d76167a5 | Michael Hanselmann |
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260 | d76167a5 | Michael Hanselmann | """
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261 | 34cb5617 | Guido Trotter | self._check_owned()
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262 | 34cb5617 | Guido Trotter | self._check_unnotified()
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263 | d76167a5 | Michael Hanselmann | |
264 | 34cb5617 | Guido Trotter | self._nwaiters += 1 |
265 | 34cb5617 | Guido Trotter | try:
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266 | 34cb5617 | Guido Trotter | if self._poller is None: |
267 | 34cb5617 | Guido Trotter | (self._read_fd, self._write_fd) = os.pipe() |
268 | 34cb5617 | Guido Trotter | self._poller = select.poll()
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269 | 34cb5617 | Guido Trotter | self._poller.register(self._read_fd, select.POLLHUP) |
270 | d76167a5 | Michael Hanselmann | |
271 | 34cb5617 | Guido Trotter | wait_fn = self._waiter_class(self._poller, self._read_fd) |
272 | 7f890059 | Guido Trotter | state = self._release_save()
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273 | 34cb5617 | Guido Trotter | try:
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274 | 34cb5617 | Guido Trotter | # Wait for notification
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275 | 34cb5617 | Guido Trotter | wait_fn(timeout) |
276 | 34cb5617 | Guido Trotter | finally:
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277 | 34cb5617 | Guido Trotter | # Re-acquire lock
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278 | 7f890059 | Guido Trotter | self._acquire_restore(state)
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279 | 34cb5617 | Guido Trotter | finally:
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280 | 34cb5617 | Guido Trotter | self._nwaiters -= 1 |
281 | 34cb5617 | Guido Trotter | if self._nwaiters == 0: |
282 | 34cb5617 | Guido Trotter | self._Cleanup()
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283 | d76167a5 | Michael Hanselmann | |
284 | b459a848 | Andrea Spadaccini | def notifyAll(self): # pylint: disable=C0103 |
285 | d76167a5 | Michael Hanselmann | """Close the writing side of the pipe to notify all waiters.
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286 | d76167a5 | Michael Hanselmann |
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287 | d76167a5 | Michael Hanselmann | """
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288 | 34cb5617 | Guido Trotter | self._check_owned()
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289 | 34cb5617 | Guido Trotter | self._check_unnotified()
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290 | 34cb5617 | Guido Trotter | self._notified = True |
291 | d76167a5 | Michael Hanselmann | if self._write_fd is not None: |
292 | d76167a5 | Michael Hanselmann | os.close(self._write_fd)
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293 | d76167a5 | Michael Hanselmann | self._write_fd = None |
294 | d76167a5 | Michael Hanselmann | |
295 | d76167a5 | Michael Hanselmann | |
296 | 34cb5617 | Guido Trotter | class PipeCondition(_BaseCondition): |
297 | 48dabc6a | Michael Hanselmann | """Group-only non-polling condition with counters.
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298 | 48dabc6a | Michael Hanselmann |
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299 | 48dabc6a | Michael Hanselmann | This condition class uses pipes and poll, internally, to be able to wait for
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300 | 48dabc6a | Michael Hanselmann | notification with a timeout, without resorting to polling. It is almost
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301 | 48dabc6a | Michael Hanselmann | compatible with Python's threading.Condition, but only supports notifyAll and
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302 | 48dabc6a | Michael Hanselmann | non-recursive locks. As an additional features it's able to report whether
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303 | 48dabc6a | Michael Hanselmann | there are any waiting threads.
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304 | 48dabc6a | Michael Hanselmann |
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305 | 48dabc6a | Michael Hanselmann | """
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306 | 154b9580 | Balazs Lecz | __slots__ = [ |
307 | c31825f7 | Michael Hanselmann | "_waiters",
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308 | 34cb5617 | Guido Trotter | "_single_condition",
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309 | 48dabc6a | Michael Hanselmann | ] |
310 | 48dabc6a | Michael Hanselmann | |
311 | 34cb5617 | Guido Trotter | _single_condition_class = SingleNotifyPipeCondition |
312 | 48dabc6a | Michael Hanselmann | |
313 | 48dabc6a | Michael Hanselmann | def __init__(self, lock): |
314 | 48dabc6a | Michael Hanselmann | """Initializes this class.
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315 | 48dabc6a | Michael Hanselmann |
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316 | 48dabc6a | Michael Hanselmann | """
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317 | 2419060d | Guido Trotter | _BaseCondition.__init__(self, lock)
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318 | c31825f7 | Michael Hanselmann | self._waiters = set() |
319 | 34cb5617 | Guido Trotter | self._single_condition = self._single_condition_class(self._lock) |
320 | 48dabc6a | Michael Hanselmann | |
321 | 83f2d5f6 | Michael Hanselmann | def wait(self, timeout): |
322 | 48dabc6a | Michael Hanselmann | """Wait for a notification.
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323 | 48dabc6a | Michael Hanselmann |
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324 | 48dabc6a | Michael Hanselmann | @type timeout: float or None
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325 | 48dabc6a | Michael Hanselmann | @param timeout: Waiting timeout (can be None)
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326 | 48dabc6a | Michael Hanselmann |
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327 | 48dabc6a | Michael Hanselmann | """
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328 | 48dabc6a | Michael Hanselmann | self._check_owned()
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329 | 48dabc6a | Michael Hanselmann | |
330 | 48dabc6a | Michael Hanselmann | # Keep local reference to the pipe. It could be replaced by another thread
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331 | 48dabc6a | Michael Hanselmann | # notifying while we're waiting.
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332 | c31825f7 | Michael Hanselmann | cond = self._single_condition
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333 | 48dabc6a | Michael Hanselmann | |
334 | c31825f7 | Michael Hanselmann | self._waiters.add(threading.currentThread())
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335 | 48dabc6a | Michael Hanselmann | try:
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336 | c31825f7 | Michael Hanselmann | cond.wait(timeout) |
337 | 48dabc6a | Michael Hanselmann | finally:
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338 | c31825f7 | Michael Hanselmann | self._check_owned()
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339 | c31825f7 | Michael Hanselmann | self._waiters.remove(threading.currentThread())
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340 | 48dabc6a | Michael Hanselmann | |
341 | b459a848 | Andrea Spadaccini | def notifyAll(self): # pylint: disable=C0103 |
342 | 48dabc6a | Michael Hanselmann | """Notify all currently waiting threads.
|
343 | 48dabc6a | Michael Hanselmann |
|
344 | 48dabc6a | Michael Hanselmann | """
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345 | 48dabc6a | Michael Hanselmann | self._check_owned()
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346 | 34cb5617 | Guido Trotter | self._single_condition.notifyAll()
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347 | 34cb5617 | Guido Trotter | self._single_condition = self._single_condition_class(self._lock) |
348 | 48dabc6a | Michael Hanselmann | |
349 | c31825f7 | Michael Hanselmann | def get_waiting(self): |
350 | c31825f7 | Michael Hanselmann | """Returns a list of all waiting threads.
|
351 | c31825f7 | Michael Hanselmann |
|
352 | c31825f7 | Michael Hanselmann | """
|
353 | c31825f7 | Michael Hanselmann | self._check_owned()
|
354 | c31825f7 | Michael Hanselmann | |
355 | c31825f7 | Michael Hanselmann | return self._waiters |
356 | c31825f7 | Michael Hanselmann | |
357 | 48dabc6a | Michael Hanselmann | def has_waiting(self): |
358 | 48dabc6a | Michael Hanselmann | """Returns whether there are active waiters.
|
359 | 48dabc6a | Michael Hanselmann |
|
360 | 48dabc6a | Michael Hanselmann | """
|
361 | 48dabc6a | Michael Hanselmann | self._check_owned()
|
362 | 48dabc6a | Michael Hanselmann | |
363 | c31825f7 | Michael Hanselmann | return bool(self._waiters) |
364 | 48dabc6a | Michael Hanselmann | |
365 | 20699809 | Michael Hanselmann | def __repr__(self): |
366 | 20699809 | Michael Hanselmann | return ("<%s.%s waiters=%s at %#x>" % |
367 | 20699809 | Michael Hanselmann | (self.__class__.__module__, self.__class__.__name__, |
368 | 20699809 | Michael Hanselmann | self._waiters, id(self))) |
369 | 20699809 | Michael Hanselmann | |
370 | 48dabc6a | Michael Hanselmann | |
371 | 887c7aa6 | Michael Hanselmann | class _PipeConditionWithMode(PipeCondition): |
372 | 887c7aa6 | Michael Hanselmann | __slots__ = [ |
373 | 887c7aa6 | Michael Hanselmann | "shared",
|
374 | 887c7aa6 | Michael Hanselmann | ] |
375 | 887c7aa6 | Michael Hanselmann | |
376 | 887c7aa6 | Michael Hanselmann | def __init__(self, lock, shared): |
377 | 887c7aa6 | Michael Hanselmann | """Initializes this class.
|
378 | 887c7aa6 | Michael Hanselmann |
|
379 | 887c7aa6 | Michael Hanselmann | """
|
380 | 887c7aa6 | Michael Hanselmann | self.shared = shared
|
381 | 887c7aa6 | Michael Hanselmann | PipeCondition.__init__(self, lock)
|
382 | 887c7aa6 | Michael Hanselmann | |
383 | 887c7aa6 | Michael Hanselmann | |
384 | 84e344d4 | Michael Hanselmann | class SharedLock(object): |
385 | 162c1c1f | Guido Trotter | """Implements a shared lock.
|
386 | 162c1c1f | Guido Trotter |
|
387 | 05ad571c | Michael Hanselmann | Multiple threads can acquire the lock in a shared way by calling
|
388 | 05ad571c | Michael Hanselmann | C{acquire(shared=1)}. In order to acquire the lock in an exclusive way
|
389 | 05ad571c | Michael Hanselmann | threads can call C{acquire(shared=0)}.
|
390 | 162c1c1f | Guido Trotter |
|
391 | 887c7aa6 | Michael Hanselmann | Notes on data structures: C{__pending} contains a priority queue (heapq) of
|
392 | 887c7aa6 | Michael Hanselmann | all pending acquires: C{[(priority1: prioqueue1), (priority2: prioqueue2),
|
393 | 887c7aa6 | Michael Hanselmann | ...]}. Each per-priority queue contains a normal in-order list of conditions
|
394 | 887c7aa6 | Michael Hanselmann | to be notified when the lock can be acquired. Shared locks are grouped
|
395 | 887c7aa6 | Michael Hanselmann | together by priority and the condition for them is stored in
|
396 | 887c7aa6 | Michael Hanselmann | C{__pending_shared} if it already exists. C{__pending_by_prio} keeps
|
397 | 887c7aa6 | Michael Hanselmann | references for the per-priority queues indexed by priority for faster access.
|
398 | 162c1c1f | Guido Trotter |
|
399 | 7f93570a | Iustin Pop | @type name: string
|
400 | 7f93570a | Iustin Pop | @ivar name: the name of the lock
|
401 | 7f93570a | Iustin Pop |
|
402 | 162c1c1f | Guido Trotter | """
|
403 | 84e344d4 | Michael Hanselmann | __slots__ = [ |
404 | 19b9ba9a | Michael Hanselmann | "__weakref__",
|
405 | 84e344d4 | Michael Hanselmann | "__deleted",
|
406 | 84e344d4 | Michael Hanselmann | "__exc",
|
407 | 84e344d4 | Michael Hanselmann | "__lock",
|
408 | 84e344d4 | Michael Hanselmann | "__pending",
|
409 | 887c7aa6 | Michael Hanselmann | "__pending_by_prio",
|
410 | 887c7aa6 | Michael Hanselmann | "__pending_shared",
|
411 | 84e344d4 | Michael Hanselmann | "__shr",
|
412 | 8d7d8b57 | Michael Hanselmann | "__time_fn",
|
413 | 7f93570a | Iustin Pop | "name",
|
414 | 84e344d4 | Michael Hanselmann | ] |
415 | 84e344d4 | Michael Hanselmann | |
416 | 887c7aa6 | Michael Hanselmann | __condition_class = _PipeConditionWithMode |
417 | 84e344d4 | Michael Hanselmann | |
418 | 8d7d8b57 | Michael Hanselmann | def __init__(self, name, monitor=None, _time_fn=time.time): |
419 | 84e344d4 | Michael Hanselmann | """Construct a new SharedLock.
|
420 | 84e344d4 | Michael Hanselmann |
|
421 | 7f93570a | Iustin Pop | @param name: the name of the lock
|
422 | 19b9ba9a | Michael Hanselmann | @type monitor: L{LockMonitor}
|
423 | 19b9ba9a | Michael Hanselmann | @param monitor: Lock monitor with which to register
|
424 | 7f93570a | Iustin Pop |
|
425 | 84e344d4 | Michael Hanselmann | """
|
426 | 84e344d4 | Michael Hanselmann | object.__init__(self) |
427 | 84e344d4 | Michael Hanselmann | |
428 | 7f93570a | Iustin Pop | self.name = name
|
429 | 7f93570a | Iustin Pop | |
430 | 8d7d8b57 | Michael Hanselmann | # Used for unittesting
|
431 | 8d7d8b57 | Michael Hanselmann | self.__time_fn = _time_fn
|
432 | 8d7d8b57 | Michael Hanselmann | |
433 | 84e344d4 | Michael Hanselmann | # Internal lock
|
434 | 162c1c1f | Guido Trotter | self.__lock = threading.Lock()
|
435 | 162c1c1f | Guido Trotter | |
436 | 84e344d4 | Michael Hanselmann | # Queue containing waiting acquires
|
437 | 84e344d4 | Michael Hanselmann | self.__pending = []
|
438 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio = {}
|
439 | 887c7aa6 | Michael Hanselmann | self.__pending_shared = {}
|
440 | 84e344d4 | Michael Hanselmann | |
441 | 84e344d4 | Michael Hanselmann | # Current lock holders
|
442 | 162c1c1f | Guido Trotter | self.__shr = set() |
443 | 162c1c1f | Guido Trotter | self.__exc = None |
444 | 162c1c1f | Guido Trotter | |
445 | a95fd5d7 | Guido Trotter | # is this lock in the deleted state?
|
446 | a95fd5d7 | Guido Trotter | self.__deleted = False |
447 | a95fd5d7 | Guido Trotter | |
448 | 19b9ba9a | Michael Hanselmann | # Register with lock monitor
|
449 | 19b9ba9a | Michael Hanselmann | if monitor:
|
450 | 44b4eddc | Michael Hanselmann | logging.debug("Adding lock %s to monitor", name)
|
451 | 19b9ba9a | Michael Hanselmann | monitor.RegisterLock(self)
|
452 | 19b9ba9a | Michael Hanselmann | |
453 | 20699809 | Michael Hanselmann | def __repr__(self): |
454 | 20699809 | Michael Hanselmann | return ("<%s.%s name=%s at %#x>" % |
455 | 20699809 | Michael Hanselmann | (self.__class__.__module__, self.__class__.__name__, |
456 | 20699809 | Michael Hanselmann | self.name, id(self))) |
457 | 20699809 | Michael Hanselmann | |
458 | 44b4eddc | Michael Hanselmann | def GetLockInfo(self, requested): |
459 | 19b9ba9a | Michael Hanselmann | """Retrieves information for querying locks.
|
460 | 19b9ba9a | Michael Hanselmann |
|
461 | 24d16f76 | Michael Hanselmann | @type requested: set
|
462 | 24d16f76 | Michael Hanselmann | @param requested: Requested information, see C{query.LQ_*}
|
463 | 19b9ba9a | Michael Hanselmann |
|
464 | 19b9ba9a | Michael Hanselmann | """
|
465 | 19b9ba9a | Michael Hanselmann | self.__lock.acquire()
|
466 | 19b9ba9a | Michael Hanselmann | try:
|
467 | 19b9ba9a | Michael Hanselmann | # Note: to avoid unintentional race conditions, no references to
|
468 | 19b9ba9a | Michael Hanselmann | # modifiable objects should be returned unless they were created in this
|
469 | 19b9ba9a | Michael Hanselmann | # function.
|
470 | 24d16f76 | Michael Hanselmann | mode = None
|
471 | 24d16f76 | Michael Hanselmann | owner_names = None
|
472 | 24d16f76 | Michael Hanselmann | |
473 | 24d16f76 | Michael Hanselmann | if query.LQ_MODE in requested: |
474 | 24d16f76 | Michael Hanselmann | if self.__deleted: |
475 | 24d16f76 | Michael Hanselmann | mode = _DELETED_TEXT |
476 | 24d16f76 | Michael Hanselmann | assert not (self.__exc or self.__shr) |
477 | 24d16f76 | Michael Hanselmann | elif self.__exc: |
478 | 24d16f76 | Michael Hanselmann | mode = _EXCLUSIVE_TEXT |
479 | 24d16f76 | Michael Hanselmann | elif self.__shr: |
480 | 24d16f76 | Michael Hanselmann | mode = _SHARED_TEXT |
481 | 24d16f76 | Michael Hanselmann | |
482 | 24d16f76 | Michael Hanselmann | # Current owner(s) are wanted
|
483 | 24d16f76 | Michael Hanselmann | if query.LQ_OWNER in requested: |
484 | 24d16f76 | Michael Hanselmann | if self.__exc: |
485 | 24d16f76 | Michael Hanselmann | owner = [self.__exc]
|
486 | 19b9ba9a | Michael Hanselmann | else:
|
487 | 24d16f76 | Michael Hanselmann | owner = self.__shr
|
488 | 24d16f76 | Michael Hanselmann | |
489 | 24d16f76 | Michael Hanselmann | if owner:
|
490 | 24d16f76 | Michael Hanselmann | assert not self.__deleted |
491 | 24d16f76 | Michael Hanselmann | owner_names = [i.getName() for i in owner] |
492 | 19b9ba9a | Michael Hanselmann | |
493 | 24d16f76 | Michael Hanselmann | # Pending acquires are wanted
|
494 | 24d16f76 | Michael Hanselmann | if query.LQ_PENDING in requested: |
495 | 24d16f76 | Michael Hanselmann | pending = [] |
496 | 24d16f76 | Michael Hanselmann | |
497 | 24d16f76 | Michael Hanselmann | # Sorting instead of copying and using heaq functions for simplicity
|
498 | 24d16f76 | Michael Hanselmann | for (_, prioqueue) in sorted(self.__pending): |
499 | 24d16f76 | Michael Hanselmann | for cond in prioqueue: |
500 | 24d16f76 | Michael Hanselmann | if cond.shared:
|
501 | 24d16f76 | Michael Hanselmann | pendmode = _SHARED_TEXT |
502 | 24d16f76 | Michael Hanselmann | else:
|
503 | 24d16f76 | Michael Hanselmann | pendmode = _EXCLUSIVE_TEXT |
504 | 24d16f76 | Michael Hanselmann | |
505 | 24d16f76 | Michael Hanselmann | # List of names will be sorted in L{query._GetLockPending}
|
506 | 24d16f76 | Michael Hanselmann | pending.append((pendmode, [i.getName() |
507 | 24d16f76 | Michael Hanselmann | for i in cond.get_waiting()])) |
508 | 24d16f76 | Michael Hanselmann | else:
|
509 | 24d16f76 | Michael Hanselmann | pending = None
|
510 | 24d16f76 | Michael Hanselmann | |
511 | 44b4eddc | Michael Hanselmann | return [(self.name, mode, owner_names, pending)] |
512 | 19b9ba9a | Michael Hanselmann | finally:
|
513 | 19b9ba9a | Michael Hanselmann | self.__lock.release()
|
514 | 19b9ba9a | Michael Hanselmann | |
515 | 84e344d4 | Michael Hanselmann | def __check_deleted(self): |
516 | 84e344d4 | Michael Hanselmann | """Raises an exception if the lock has been deleted.
|
517 | 84e344d4 | Michael Hanselmann |
|
518 | 84e344d4 | Michael Hanselmann | """
|
519 | 84e344d4 | Michael Hanselmann | if self.__deleted: |
520 | 7f93570a | Iustin Pop | raise errors.LockError("Deleted lock %s" % self.name) |
521 | 84e344d4 | Michael Hanselmann | |
522 | 162c1c1f | Guido Trotter | def __is_sharer(self): |
523 | 84e344d4 | Michael Hanselmann | """Is the current thread sharing the lock at this time?
|
524 | 84e344d4 | Michael Hanselmann |
|
525 | 84e344d4 | Michael Hanselmann | """
|
526 | 162c1c1f | Guido Trotter | return threading.currentThread() in self.__shr |
527 | 162c1c1f | Guido Trotter | |
528 | 162c1c1f | Guido Trotter | def __is_exclusive(self): |
529 | 84e344d4 | Michael Hanselmann | """Is the current thread holding the lock exclusively at this time?
|
530 | 84e344d4 | Michael Hanselmann |
|
531 | 84e344d4 | Michael Hanselmann | """
|
532 | 162c1c1f | Guido Trotter | return threading.currentThread() == self.__exc |
533 | 162c1c1f | Guido Trotter | |
534 | 162c1c1f | Guido Trotter | def __is_owned(self, shared=-1): |
535 | 162c1c1f | Guido Trotter | """Is the current thread somehow owning the lock at this time?
|
536 | 162c1c1f | Guido Trotter |
|
537 | 162c1c1f | Guido Trotter | This is a private version of the function, which presumes you're holding
|
538 | 162c1c1f | Guido Trotter | the internal lock.
|
539 | 162c1c1f | Guido Trotter |
|
540 | 162c1c1f | Guido Trotter | """
|
541 | 162c1c1f | Guido Trotter | if shared < 0: |
542 | 162c1c1f | Guido Trotter | return self.__is_sharer() or self.__is_exclusive() |
543 | 162c1c1f | Guido Trotter | elif shared:
|
544 | 162c1c1f | Guido Trotter | return self.__is_sharer() |
545 | 162c1c1f | Guido Trotter | else:
|
546 | 162c1c1f | Guido Trotter | return self.__is_exclusive() |
547 | 162c1c1f | Guido Trotter | |
548 | ee2b99e3 | Michael Hanselmann | def is_owned(self, shared=-1): |
549 | 162c1c1f | Guido Trotter | """Is the current thread somehow owning the lock at this time?
|
550 | 162c1c1f | Guido Trotter |
|
551 | c41eea6e | Iustin Pop | @param shared:
|
552 | c41eea6e | Iustin Pop | - < 0: check for any type of ownership (default)
|
553 | c41eea6e | Iustin Pop | - 0: check for exclusive ownership
|
554 | c41eea6e | Iustin Pop | - > 0: check for shared ownership
|
555 | 162c1c1f | Guido Trotter |
|
556 | 162c1c1f | Guido Trotter | """
|
557 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
558 | 162c1c1f | Guido Trotter | try:
|
559 | 84e344d4 | Michael Hanselmann | return self.__is_owned(shared=shared) |
560 | 162c1c1f | Guido Trotter | finally:
|
561 | 162c1c1f | Guido Trotter | self.__lock.release()
|
562 | 162c1c1f | Guido Trotter | |
563 | ee2b99e3 | Michael Hanselmann | #: Necessary to remain compatible with threading.Condition, which tries to
|
564 | ee2b99e3 | Michael Hanselmann | #: retrieve a locks' "_is_owned" attribute
|
565 | ee2b99e3 | Michael Hanselmann | _is_owned = is_owned |
566 | fdfe88b1 | Michael Hanselmann | |
567 | 84e344d4 | Michael Hanselmann | def _count_pending(self): |
568 | 84e344d4 | Michael Hanselmann | """Returns the number of pending acquires.
|
569 | a95fd5d7 | Guido Trotter |
|
570 | 84e344d4 | Michael Hanselmann | @rtype: int
|
571 | a95fd5d7 | Guido Trotter |
|
572 | a95fd5d7 | Guido Trotter | """
|
573 | 84e344d4 | Michael Hanselmann | self.__lock.acquire()
|
574 | 84e344d4 | Michael Hanselmann | try:
|
575 | 887c7aa6 | Michael Hanselmann | return sum(len(prioqueue) for (_, prioqueue) in self.__pending) |
576 | 887c7aa6 | Michael Hanselmann | finally:
|
577 | 887c7aa6 | Michael Hanselmann | self.__lock.release()
|
578 | 887c7aa6 | Michael Hanselmann | |
579 | 887c7aa6 | Michael Hanselmann | def _check_empty(self): |
580 | 887c7aa6 | Michael Hanselmann | """Checks whether there are any pending acquires.
|
581 | 887c7aa6 | Michael Hanselmann |
|
582 | 887c7aa6 | Michael Hanselmann | @rtype: bool
|
583 | 887c7aa6 | Michael Hanselmann |
|
584 | 887c7aa6 | Michael Hanselmann | """
|
585 | 887c7aa6 | Michael Hanselmann | self.__lock.acquire()
|
586 | 887c7aa6 | Michael Hanselmann | try:
|
587 | 887c7aa6 | Michael Hanselmann | # Order is important: __find_first_pending_queue modifies __pending
|
588 | 113359fe | Michael Hanselmann | (_, prioqueue) = self.__find_first_pending_queue()
|
589 | 113359fe | Michael Hanselmann | |
590 | 113359fe | Michael Hanselmann | return not (prioqueue or |
591 | 887c7aa6 | Michael Hanselmann | self.__pending or |
592 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio or |
593 | 887c7aa6 | Michael Hanselmann | self.__pending_shared)
|
594 | 84e344d4 | Michael Hanselmann | finally:
|
595 | 84e344d4 | Michael Hanselmann | self.__lock.release()
|
596 | a95fd5d7 | Guido Trotter | |
597 | 84e344d4 | Michael Hanselmann | def __do_acquire(self, shared): |
598 | 84e344d4 | Michael Hanselmann | """Actually acquire the lock.
|
599 | 84e344d4 | Michael Hanselmann |
|
600 | 84e344d4 | Michael Hanselmann | """
|
601 | 84e344d4 | Michael Hanselmann | if shared:
|
602 | 84e344d4 | Michael Hanselmann | self.__shr.add(threading.currentThread())
|
603 | 84e344d4 | Michael Hanselmann | else:
|
604 | 84e344d4 | Michael Hanselmann | self.__exc = threading.currentThread()
|
605 | a95fd5d7 | Guido Trotter | |
606 | 84e344d4 | Michael Hanselmann | def __can_acquire(self, shared): |
607 | 84e344d4 | Michael Hanselmann | """Determine whether lock can be acquired.
|
608 | a95fd5d7 | Guido Trotter |
|
609 | a95fd5d7 | Guido Trotter | """
|
610 | 84e344d4 | Michael Hanselmann | if shared:
|
611 | 84e344d4 | Michael Hanselmann | return self.__exc is None |
612 | 84e344d4 | Michael Hanselmann | else:
|
613 | 84e344d4 | Michael Hanselmann | return len(self.__shr) == 0 and self.__exc is None |
614 | a95fd5d7 | Guido Trotter | |
615 | 887c7aa6 | Michael Hanselmann | def __find_first_pending_queue(self): |
616 | 887c7aa6 | Michael Hanselmann | """Tries to find the topmost queued entry with pending acquires.
|
617 | 887c7aa6 | Michael Hanselmann |
|
618 | 887c7aa6 | Michael Hanselmann | Removes empty entries while going through the list.
|
619 | 887c7aa6 | Michael Hanselmann |
|
620 | 887c7aa6 | Michael Hanselmann | """
|
621 | 887c7aa6 | Michael Hanselmann | while self.__pending: |
622 | 887c7aa6 | Michael Hanselmann | (priority, prioqueue) = self.__pending[0] |
623 | 887c7aa6 | Michael Hanselmann | |
624 | 887c7aa6 | Michael Hanselmann | if prioqueue:
|
625 | 113359fe | Michael Hanselmann | return (priority, prioqueue)
|
626 | 887c7aa6 | Michael Hanselmann | |
627 | 113359fe | Michael Hanselmann | # Remove empty queue
|
628 | 113359fe | Michael Hanselmann | heapq.heappop(self.__pending)
|
629 | 113359fe | Michael Hanselmann | del self.__pending_by_prio[priority] |
630 | 113359fe | Michael Hanselmann | assert priority not in self.__pending_shared |
631 | 113359fe | Michael Hanselmann | |
632 | 113359fe | Michael Hanselmann | return (None, None) |
633 | 887c7aa6 | Michael Hanselmann | |
634 | 84e344d4 | Michael Hanselmann | def __is_on_top(self, cond): |
635 | 84e344d4 | Michael Hanselmann | """Checks whether the passed condition is on top of the queue.
|
636 | a95fd5d7 | Guido Trotter |
|
637 | 84e344d4 | Michael Hanselmann | The caller must make sure the queue isn't empty.
|
638 | a95fd5d7 | Guido Trotter |
|
639 | 84e344d4 | Michael Hanselmann | """
|
640 | 113359fe | Michael Hanselmann | (_, prioqueue) = self.__find_first_pending_queue()
|
641 | 113359fe | Michael Hanselmann | |
642 | 113359fe | Michael Hanselmann | return cond == prioqueue[0] |
643 | 4d686df8 | Guido Trotter | |
644 | 887c7aa6 | Michael Hanselmann | def __acquire_unlocked(self, shared, timeout, priority): |
645 | 84e344d4 | Michael Hanselmann | """Acquire a shared lock.
|
646 | 9216a9f7 | Michael Hanselmann |
|
647 | 84e344d4 | Michael Hanselmann | @param shared: whether to acquire in shared mode; by default an
|
648 | 84e344d4 | Michael Hanselmann | exclusive lock will be acquired
|
649 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
650 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
651 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
652 | 9216a9f7 | Michael Hanselmann |
|
653 | 9216a9f7 | Michael Hanselmann | """
|
654 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
655 | 9216a9f7 | Michael Hanselmann | |
656 | 84e344d4 | Michael Hanselmann | # We cannot acquire the lock if we already have it
|
657 | 7f93570a | Iustin Pop | assert not self.__is_owned(), ("double acquire() on a non-recursive lock" |
658 | 7f93570a | Iustin Pop | " %s" % self.name) |
659 | 84e344d4 | Michael Hanselmann | |
660 | 887c7aa6 | Michael Hanselmann | # Remove empty entries from queue
|
661 | 887c7aa6 | Michael Hanselmann | self.__find_first_pending_queue()
|
662 | 887c7aa6 | Michael Hanselmann | |
663 | 84e344d4 | Michael Hanselmann | # Check whether someone else holds the lock or there are pending acquires.
|
664 | 84e344d4 | Michael Hanselmann | if not self.__pending and self.__can_acquire(shared): |
665 | 84e344d4 | Michael Hanselmann | # Apparently not, can acquire lock directly.
|
666 | 84e344d4 | Michael Hanselmann | self.__do_acquire(shared)
|
667 | 84e344d4 | Michael Hanselmann | return True |
668 | 9216a9f7 | Michael Hanselmann | |
669 | 03c5291c | Michael Hanselmann | # The lock couldn't be acquired right away, so if a timeout is given and is
|
670 | 03c5291c | Michael Hanselmann | # considered too short, return right away as scheduling a pending
|
671 | 03c5291c | Michael Hanselmann | # acquisition is quite expensive
|
672 | 03c5291c | Michael Hanselmann | if timeout is not None and timeout < _LOCK_ACQUIRE_MIN_TIMEOUT: |
673 | 03c5291c | Michael Hanselmann | return False |
674 | 03c5291c | Michael Hanselmann | |
675 | 887c7aa6 | Michael Hanselmann | prioqueue = self.__pending_by_prio.get(priority, None) |
676 | 9216a9f7 | Michael Hanselmann | |
677 | 887c7aa6 | Michael Hanselmann | if shared:
|
678 | 887c7aa6 | Michael Hanselmann | # Try to re-use condition for shared acquire
|
679 | 887c7aa6 | Michael Hanselmann | wait_condition = self.__pending_shared.get(priority, None) |
680 | 887c7aa6 | Michael Hanselmann | assert (wait_condition is None or |
681 | 887c7aa6 | Michael Hanselmann | (wait_condition.shared and wait_condition in prioqueue)) |
682 | 84e344d4 | Michael Hanselmann | else:
|
683 | 887c7aa6 | Michael Hanselmann | wait_condition = None
|
684 | 887c7aa6 | Michael Hanselmann | |
685 | 887c7aa6 | Michael Hanselmann | if wait_condition is None: |
686 | 887c7aa6 | Michael Hanselmann | if prioqueue is None: |
687 | 887c7aa6 | Michael Hanselmann | assert priority not in self.__pending_by_prio |
688 | 887c7aa6 | Michael Hanselmann | |
689 | 887c7aa6 | Michael Hanselmann | prioqueue = [] |
690 | 887c7aa6 | Michael Hanselmann | heapq.heappush(self.__pending, (priority, prioqueue))
|
691 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio[priority] = prioqueue
|
692 | 887c7aa6 | Michael Hanselmann | |
693 | 887c7aa6 | Michael Hanselmann | wait_condition = self.__condition_class(self.__lock, shared) |
694 | 887c7aa6 | Michael Hanselmann | prioqueue.append(wait_condition) |
695 | 887c7aa6 | Michael Hanselmann | |
696 | 887c7aa6 | Michael Hanselmann | if shared:
|
697 | 887c7aa6 | Michael Hanselmann | # Keep reference for further shared acquires on same priority. This is
|
698 | 887c7aa6 | Michael Hanselmann | # better than trying to find it in the list of pending acquires.
|
699 | 887c7aa6 | Michael Hanselmann | assert priority not in self.__pending_shared |
700 | 887c7aa6 | Michael Hanselmann | self.__pending_shared[priority] = wait_condition
|
701 | 84e344d4 | Michael Hanselmann | |
702 | 8d7d8b57 | Michael Hanselmann | wait_start = self.__time_fn()
|
703 | 8d7d8b57 | Michael Hanselmann | acquired = False
|
704 | 8d7d8b57 | Michael Hanselmann | |
705 | 84e344d4 | Michael Hanselmann | try:
|
706 | 84e344d4 | Michael Hanselmann | # Wait until we become the topmost acquire in the queue or the timeout
|
707 | 84e344d4 | Michael Hanselmann | # expires.
|
708 | 8d7d8b57 | Michael Hanselmann | while True: |
709 | 8d7d8b57 | Michael Hanselmann | if self.__is_on_top(wait_condition) and self.__can_acquire(shared): |
710 | 8d7d8b57 | Michael Hanselmann | self.__do_acquire(shared)
|
711 | 8d7d8b57 | Michael Hanselmann | acquired = True
|
712 | 8d7d8b57 | Michael Hanselmann | break
|
713 | 84e344d4 | Michael Hanselmann | |
714 | 8d7d8b57 | Michael Hanselmann | # A lot of code assumes blocking acquires always succeed, therefore we
|
715 | 8d7d8b57 | Michael Hanselmann | # can never return False for a blocking acquire
|
716 | 8d7d8b57 | Michael Hanselmann | if (timeout is not None and |
717 | 8d7d8b57 | Michael Hanselmann | utils.TimeoutExpired(wait_start, timeout, _time_fn=self.__time_fn)):
|
718 | 84e344d4 | Michael Hanselmann | break
|
719 | 84e344d4 | Michael Hanselmann | |
720 | 8d7d8b57 | Michael Hanselmann | # Wait for notification
|
721 | 8d7d8b57 | Michael Hanselmann | wait_condition.wait(timeout) |
722 | 8d7d8b57 | Michael Hanselmann | self.__check_deleted()
|
723 | 9216a9f7 | Michael Hanselmann | finally:
|
724 | 84e344d4 | Michael Hanselmann | # Remove condition from queue if there are no more waiters
|
725 | 887c7aa6 | Michael Hanselmann | if not wait_condition.has_waiting(): |
726 | 887c7aa6 | Michael Hanselmann | prioqueue.remove(wait_condition) |
727 | 887c7aa6 | Michael Hanselmann | if wait_condition.shared:
|
728 | 113359fe | Michael Hanselmann | # Remove from list of shared acquires if it wasn't while releasing
|
729 | 113359fe | Michael Hanselmann | # (e.g. on lock deletion)
|
730 | 113359fe | Michael Hanselmann | self.__pending_shared.pop(priority, None) |
731 | 9216a9f7 | Michael Hanselmann | |
732 | 8d7d8b57 | Michael Hanselmann | return acquired
|
733 | 9216a9f7 | Michael Hanselmann | |
734 | 7100c2fa | Michael Hanselmann | def acquire(self, shared=0, timeout=None, priority=None, |
735 | 887c7aa6 | Michael Hanselmann | test_notify=None):
|
736 | 162c1c1f | Guido Trotter | """Acquire a shared lock.
|
737 | 162c1c1f | Guido Trotter |
|
738 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
739 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default an
|
740 | c41eea6e | Iustin Pop | exclusive lock will be acquired
|
741 | 84e344d4 | Michael Hanselmann | @type timeout: float
|
742 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
743 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
744 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
745 | 008b92fa | Michael Hanselmann | @type test_notify: callable or None
|
746 | 008b92fa | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
747 | 162c1c1f | Guido Trotter |
|
748 | 162c1c1f | Guido Trotter | """
|
749 | 7100c2fa | Michael Hanselmann | if priority is None: |
750 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
751 | 7100c2fa | Michael Hanselmann | |
752 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
753 | 162c1c1f | Guido Trotter | try:
|
754 | 008b92fa | Michael Hanselmann | # We already got the lock, notify now
|
755 | 008b92fa | Michael Hanselmann | if __debug__ and callable(test_notify): |
756 | 008b92fa | Michael Hanselmann | test_notify() |
757 | 008b92fa | Michael Hanselmann | |
758 | 887c7aa6 | Michael Hanselmann | return self.__acquire_unlocked(shared, timeout, priority) |
759 | 162c1c1f | Guido Trotter | finally:
|
760 | 162c1c1f | Guido Trotter | self.__lock.release()
|
761 | 162c1c1f | Guido Trotter | |
762 | 3dbe3ddf | Michael Hanselmann | def downgrade(self): |
763 | 3dbe3ddf | Michael Hanselmann | """Changes the lock mode from exclusive to shared.
|
764 | 3dbe3ddf | Michael Hanselmann |
|
765 | 3dbe3ddf | Michael Hanselmann | Pending acquires in shared mode on the same priority will go ahead.
|
766 | 3dbe3ddf | Michael Hanselmann |
|
767 | 3dbe3ddf | Michael Hanselmann | """
|
768 | 3dbe3ddf | Michael Hanselmann | self.__lock.acquire()
|
769 | 3dbe3ddf | Michael Hanselmann | try:
|
770 | 3dbe3ddf | Michael Hanselmann | assert self.__is_owned(), "Lock must be owned" |
771 | 3dbe3ddf | Michael Hanselmann | |
772 | 3dbe3ddf | Michael Hanselmann | if self.__is_exclusive(): |
773 | 3dbe3ddf | Michael Hanselmann | # Do nothing if the lock is already acquired in shared mode
|
774 | 3dbe3ddf | Michael Hanselmann | self.__exc = None |
775 | 3dbe3ddf | Michael Hanselmann | self.__do_acquire(1) |
776 | 3dbe3ddf | Michael Hanselmann | |
777 | 3dbe3ddf | Michael Hanselmann | # Important: pending shared acquires should only jump ahead if there
|
778 | 3dbe3ddf | Michael Hanselmann | # was a transition from exclusive to shared, otherwise an owner of a
|
779 | 3dbe3ddf | Michael Hanselmann | # shared lock can keep calling this function to push incoming shared
|
780 | 3dbe3ddf | Michael Hanselmann | # acquires
|
781 | 3dbe3ddf | Michael Hanselmann | (priority, prioqueue) = self.__find_first_pending_queue()
|
782 | 3dbe3ddf | Michael Hanselmann | if prioqueue:
|
783 | 3dbe3ddf | Michael Hanselmann | # Is there a pending shared acquire on this priority?
|
784 | 3dbe3ddf | Michael Hanselmann | cond = self.__pending_shared.pop(priority, None) |
785 | 3dbe3ddf | Michael Hanselmann | if cond:
|
786 | 3dbe3ddf | Michael Hanselmann | assert cond.shared
|
787 | 3dbe3ddf | Michael Hanselmann | assert cond in prioqueue |
788 | 3dbe3ddf | Michael Hanselmann | |
789 | 3dbe3ddf | Michael Hanselmann | # Ensure shared acquire is on top of queue
|
790 | 3dbe3ddf | Michael Hanselmann | if len(prioqueue) > 1: |
791 | 3dbe3ddf | Michael Hanselmann | prioqueue.remove(cond) |
792 | 3dbe3ddf | Michael Hanselmann | prioqueue.insert(0, cond)
|
793 | 3dbe3ddf | Michael Hanselmann | |
794 | 3dbe3ddf | Michael Hanselmann | # Notify
|
795 | 3dbe3ddf | Michael Hanselmann | cond.notifyAll() |
796 | 3dbe3ddf | Michael Hanselmann | |
797 | 3dbe3ddf | Michael Hanselmann | assert not self.__is_exclusive() |
798 | 3dbe3ddf | Michael Hanselmann | assert self.__is_sharer() |
799 | 3dbe3ddf | Michael Hanselmann | |
800 | 3dbe3ddf | Michael Hanselmann | return True |
801 | 3dbe3ddf | Michael Hanselmann | finally:
|
802 | 3dbe3ddf | Michael Hanselmann | self.__lock.release()
|
803 | 3dbe3ddf | Michael Hanselmann | |
804 | 162c1c1f | Guido Trotter | def release(self): |
805 | 162c1c1f | Guido Trotter | """Release a Shared Lock.
|
806 | 162c1c1f | Guido Trotter |
|
807 | 162c1c1f | Guido Trotter | You must have acquired the lock, either in shared or in exclusive mode,
|
808 | 162c1c1f | Guido Trotter | before calling this function.
|
809 | 162c1c1f | Guido Trotter |
|
810 | 162c1c1f | Guido Trotter | """
|
811 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
812 | 162c1c1f | Guido Trotter | try:
|
813 | 84e344d4 | Michael Hanselmann | assert self.__is_exclusive() or self.__is_sharer(), \ |
814 | 84e344d4 | Michael Hanselmann | "Cannot release non-owned lock"
|
815 | 84e344d4 | Michael Hanselmann | |
816 | 162c1c1f | Guido Trotter | # Autodetect release type
|
817 | 162c1c1f | Guido Trotter | if self.__is_exclusive(): |
818 | 162c1c1f | Guido Trotter | self.__exc = None |
819 | 70567db0 | Michael Hanselmann | notify = True
|
820 | 84e344d4 | Michael Hanselmann | else:
|
821 | 162c1c1f | Guido Trotter | self.__shr.remove(threading.currentThread())
|
822 | 70567db0 | Michael Hanselmann | notify = not self.__shr |
823 | 162c1c1f | Guido Trotter | |
824 | 70567db0 | Michael Hanselmann | # Notify topmost condition in queue if there are no owners left (for
|
825 | 70567db0 | Michael Hanselmann | # shared locks)
|
826 | 70567db0 | Michael Hanselmann | if notify:
|
827 | 70567db0 | Michael Hanselmann | self.__notify_topmost()
|
828 | 8d7d8b57 | Michael Hanselmann | finally:
|
829 | 8d7d8b57 | Michael Hanselmann | self.__lock.release()
|
830 | 8d7d8b57 | Michael Hanselmann | |
831 | 8d7d8b57 | Michael Hanselmann | def __notify_topmost(self): |
832 | 8d7d8b57 | Michael Hanselmann | """Notifies topmost condition in queue of pending acquires.
|
833 | 8d7d8b57 | Michael Hanselmann |
|
834 | 8d7d8b57 | Michael Hanselmann | """
|
835 | 8d7d8b57 | Michael Hanselmann | (priority, prioqueue) = self.__find_first_pending_queue()
|
836 | 8d7d8b57 | Michael Hanselmann | if prioqueue:
|
837 | 8d7d8b57 | Michael Hanselmann | cond = prioqueue[0]
|
838 | 8d7d8b57 | Michael Hanselmann | cond.notifyAll() |
839 | 8d7d8b57 | Michael Hanselmann | if cond.shared:
|
840 | 8d7d8b57 | Michael Hanselmann | # Prevent further shared acquires from sneaking in while waiters are
|
841 | 8d7d8b57 | Michael Hanselmann | # notified
|
842 | 8d7d8b57 | Michael Hanselmann | self.__pending_shared.pop(priority, None) |
843 | 8d7d8b57 | Michael Hanselmann | |
844 | 8d7d8b57 | Michael Hanselmann | def _notify_topmost(self): |
845 | 8d7d8b57 | Michael Hanselmann | """Exported version of L{__notify_topmost}.
|
846 | 162c1c1f | Guido Trotter |
|
847 | 8d7d8b57 | Michael Hanselmann | """
|
848 | 8d7d8b57 | Michael Hanselmann | self.__lock.acquire()
|
849 | 8d7d8b57 | Michael Hanselmann | try:
|
850 | 8d7d8b57 | Michael Hanselmann | return self.__notify_topmost() |
851 | 162c1c1f | Guido Trotter | finally:
|
852 | 162c1c1f | Guido Trotter | self.__lock.release()
|
853 | 162c1c1f | Guido Trotter | |
854 | 7100c2fa | Michael Hanselmann | def delete(self, timeout=None, priority=None): |
855 | a95fd5d7 | Guido Trotter | """Delete a Shared Lock.
|
856 | a95fd5d7 | Guido Trotter |
|
857 | a95fd5d7 | Guido Trotter | This operation will declare the lock for removal. First the lock will be
|
858 | a95fd5d7 | Guido Trotter | acquired in exclusive mode if you don't already own it, then the lock
|
859 | a95fd5d7 | Guido Trotter | will be put in a state where any future and pending acquire() fail.
|
860 | a95fd5d7 | Guido Trotter |
|
861 | 84e344d4 | Michael Hanselmann | @type timeout: float
|
862 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
863 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
864 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
865 | a95fd5d7 | Guido Trotter |
|
866 | a95fd5d7 | Guido Trotter | """
|
867 | 7100c2fa | Michael Hanselmann | if priority is None: |
868 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
869 | 7100c2fa | Michael Hanselmann | |
870 | a95fd5d7 | Guido Trotter | self.__lock.acquire()
|
871 | a95fd5d7 | Guido Trotter | try:
|
872 | 84e344d4 | Michael Hanselmann | assert not self.__is_sharer(), "Cannot delete() a lock while sharing it" |
873 | 84e344d4 | Michael Hanselmann | |
874 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
875 | a95fd5d7 | Guido Trotter | |
876 | 84e344d4 | Michael Hanselmann | # The caller is allowed to hold the lock exclusively already.
|
877 | 84e344d4 | Michael Hanselmann | acquired = self.__is_exclusive()
|
878 | a95fd5d7 | Guido Trotter | |
879 | 84e344d4 | Michael Hanselmann | if not acquired: |
880 | 887c7aa6 | Michael Hanselmann | acquired = self.__acquire_unlocked(0, timeout, priority) |
881 | a66bd91b | Michael Hanselmann | |
882 | 26082b7e | Michael Hanselmann | if acquired:
|
883 | a66bd91b | Michael Hanselmann | assert self.__is_exclusive() and not self.__is_sharer(), \ |
884 | a66bd91b | Michael Hanselmann | "Lock wasn't acquired in exclusive mode"
|
885 | 84e344d4 | Michael Hanselmann | |
886 | 84e344d4 | Michael Hanselmann | self.__deleted = True |
887 | 84e344d4 | Michael Hanselmann | self.__exc = None |
888 | a95fd5d7 | Guido Trotter | |
889 | 19b9ba9a | Michael Hanselmann | assert not (self.__exc or self.__shr), "Found owner during deletion" |
890 | 19b9ba9a | Michael Hanselmann | |
891 | 84e344d4 | Michael Hanselmann | # Notify all acquires. They'll throw an error.
|
892 | 887c7aa6 | Michael Hanselmann | for (_, prioqueue) in self.__pending: |
893 | 887c7aa6 | Michael Hanselmann | for cond in prioqueue: |
894 | 887c7aa6 | Michael Hanselmann | cond.notifyAll() |
895 | 887c7aa6 | Michael Hanselmann | |
896 | 887c7aa6 | Michael Hanselmann | assert self.__deleted |
897 | a95fd5d7 | Guido Trotter | |
898 | 84e344d4 | Michael Hanselmann | return acquired
|
899 | a95fd5d7 | Guido Trotter | finally:
|
900 | a95fd5d7 | Guido Trotter | self.__lock.release()
|
901 | a95fd5d7 | Guido Trotter | |
902 | 1a4e32d0 | Guido Trotter | def _release_save(self): |
903 | 1a4e32d0 | Guido Trotter | shared = self.__is_sharer()
|
904 | 1a4e32d0 | Guido Trotter | self.release()
|
905 | 1a4e32d0 | Guido Trotter | return shared
|
906 | 1a4e32d0 | Guido Trotter | |
907 | 1a4e32d0 | Guido Trotter | def _acquire_restore(self, shared): |
908 | 1a4e32d0 | Guido Trotter | self.acquire(shared=shared)
|
909 | 1a4e32d0 | Guido Trotter | |
910 | aaae9bc0 | Guido Trotter | |
911 | f12eadb3 | Iustin Pop | # Whenever we want to acquire a full LockSet we pass None as the value
|
912 | 5bbd3f7f | Michael Hanselmann | # to acquire. Hide this behind this nicely named constant.
|
913 | e310b019 | Guido Trotter | ALL_SET = None
|
914 | e310b019 | Guido Trotter | |
915 | e310b019 | Guido Trotter | |
916 | 5aab242c | Michael Hanselmann | class _AcquireTimeout(Exception): |
917 | 5aab242c | Michael Hanselmann | """Internal exception to abort an acquire on a timeout.
|
918 | 5aab242c | Michael Hanselmann |
|
919 | 5aab242c | Michael Hanselmann | """
|
920 | 5aab242c | Michael Hanselmann | |
921 | 5aab242c | Michael Hanselmann | |
922 | aaae9bc0 | Guido Trotter | class LockSet: |
923 | aaae9bc0 | Guido Trotter | """Implements a set of locks.
|
924 | aaae9bc0 | Guido Trotter |
|
925 | aaae9bc0 | Guido Trotter | This abstraction implements a set of shared locks for the same resource type,
|
926 | aaae9bc0 | Guido Trotter | distinguished by name. The user can lock a subset of the resources and the
|
927 | aaae9bc0 | Guido Trotter | LockSet will take care of acquiring the locks always in the same order, thus
|
928 | aaae9bc0 | Guido Trotter | preventing deadlock.
|
929 | aaae9bc0 | Guido Trotter |
|
930 | aaae9bc0 | Guido Trotter | All the locks needed in the same set must be acquired together, though.
|
931 | aaae9bc0 | Guido Trotter |
|
932 | 7f93570a | Iustin Pop | @type name: string
|
933 | 7f93570a | Iustin Pop | @ivar name: the name of the lockset
|
934 | 7f93570a | Iustin Pop |
|
935 | aaae9bc0 | Guido Trotter | """
|
936 | 19b9ba9a | Michael Hanselmann | def __init__(self, members, name, monitor=None): |
937 | aaae9bc0 | Guido Trotter | """Constructs a new LockSet.
|
938 | aaae9bc0 | Guido Trotter |
|
939 | ec44d893 | Guido Trotter | @type members: list of strings
|
940 | c41eea6e | Iustin Pop | @param members: initial members of the set
|
941 | 19b9ba9a | Michael Hanselmann | @type monitor: L{LockMonitor}
|
942 | 19b9ba9a | Michael Hanselmann | @param monitor: Lock monitor with which to register member locks
|
943 | aaae9bc0 | Guido Trotter |
|
944 | aaae9bc0 | Guido Trotter | """
|
945 | 7f93570a | Iustin Pop | assert members is not None, "members parameter is not a list" |
946 | 7f93570a | Iustin Pop | self.name = name
|
947 | 7f93570a | Iustin Pop | |
948 | 19b9ba9a | Michael Hanselmann | # Lock monitor
|
949 | 19b9ba9a | Michael Hanselmann | self.__monitor = monitor
|
950 | 19b9ba9a | Michael Hanselmann | |
951 | c307ee34 | Michael Hanselmann | # Used internally to guarantee coherency
|
952 | c307ee34 | Michael Hanselmann | self.__lock = SharedLock(self._GetLockName("[lockset]"), monitor=monitor) |
953 | aaae9bc0 | Guido Trotter | |
954 | aaae9bc0 | Guido Trotter | # The lockdict indexes the relationship name -> lock
|
955 | aaae9bc0 | Guido Trotter | # The order-of-locking is implied by the alphabetical order of names
|
956 | aaae9bc0 | Guido Trotter | self.__lockdict = {}
|
957 | aaae9bc0 | Guido Trotter | |
958 | 7f93570a | Iustin Pop | for mname in members: |
959 | 19b9ba9a | Michael Hanselmann | self.__lockdict[mname] = SharedLock(self._GetLockName(mname), |
960 | 19b9ba9a | Michael Hanselmann | monitor=monitor) |
961 | aaae9bc0 | Guido Trotter | |
962 | aaae9bc0 | Guido Trotter | # The owner dict contains the set of locks each thread owns. For
|
963 | aaae9bc0 | Guido Trotter | # performance each thread can access its own key without a global lock on
|
964 | aaae9bc0 | Guido Trotter | # this structure. It is paramount though that *no* other type of access is
|
965 | aaae9bc0 | Guido Trotter | # done to this structure (eg. no looping over its keys). *_owner helper
|
966 | aaae9bc0 | Guido Trotter | # function are defined to guarantee access is correct, but in general never
|
967 | aaae9bc0 | Guido Trotter | # do anything different than __owners[threading.currentThread()], or there
|
968 | aaae9bc0 | Guido Trotter | # will be trouble.
|
969 | aaae9bc0 | Guido Trotter | self.__owners = {}
|
970 | aaae9bc0 | Guido Trotter | |
971 | 4fb780d1 | Michael Hanselmann | def _GetLockName(self, mname): |
972 | 4fb780d1 | Michael Hanselmann | """Returns the name for a member lock.
|
973 | 4fb780d1 | Michael Hanselmann |
|
974 | 4fb780d1 | Michael Hanselmann | """
|
975 | 4fb780d1 | Michael Hanselmann | return "%s/%s" % (self.name, mname) |
976 | 4fb780d1 | Michael Hanselmann | |
977 | 3dbe3ddf | Michael Hanselmann | def _get_lock(self): |
978 | 3dbe3ddf | Michael Hanselmann | """Returns the lockset-internal lock.
|
979 | 3dbe3ddf | Michael Hanselmann |
|
980 | 3dbe3ddf | Michael Hanselmann | """
|
981 | 3dbe3ddf | Michael Hanselmann | return self.__lock |
982 | 3dbe3ddf | Michael Hanselmann | |
983 | 3dbe3ddf | Michael Hanselmann | def _get_lockdict(self): |
984 | 3dbe3ddf | Michael Hanselmann | """Returns the lockset-internal lock dictionary.
|
985 | 3dbe3ddf | Michael Hanselmann |
|
986 | 3dbe3ddf | Michael Hanselmann | Accessing this structure is only safe in single-thread usage or when the
|
987 | 3dbe3ddf | Michael Hanselmann | lockset-internal lock is held.
|
988 | 3dbe3ddf | Michael Hanselmann |
|
989 | 3dbe3ddf | Michael Hanselmann | """
|
990 | 3dbe3ddf | Michael Hanselmann | return self.__lockdict |
991 | 3dbe3ddf | Michael Hanselmann | |
992 | ee2b99e3 | Michael Hanselmann | def is_owned(self): |
993 | c6a622cf | Michael Hanselmann | """Is the current thread a current level owner?
|
994 | c6a622cf | Michael Hanselmann |
|
995 | c6a622cf | Michael Hanselmann | @note: Use L{check_owned} to check if a specific lock is held
|
996 | c6a622cf | Michael Hanselmann |
|
997 | c6a622cf | Michael Hanselmann | """
|
998 | aaae9bc0 | Guido Trotter | return threading.currentThread() in self.__owners |
999 | aaae9bc0 | Guido Trotter | |
1000 | c6a622cf | Michael Hanselmann | def check_owned(self, names, shared=-1): |
1001 | c6a622cf | Michael Hanselmann | """Check if locks are owned in a specific mode.
|
1002 | c6a622cf | Michael Hanselmann |
|
1003 | c6a622cf | Michael Hanselmann | @type names: sequence or string
|
1004 | c6a622cf | Michael Hanselmann | @param names: Lock names (or a single lock name)
|
1005 | c6a622cf | Michael Hanselmann | @param shared: See L{SharedLock.is_owned}
|
1006 | c6a622cf | Michael Hanselmann | @rtype: bool
|
1007 | c6a622cf | Michael Hanselmann | @note: Use L{is_owned} to check if the current thread holds I{any} lock and
|
1008 | c6a622cf | Michael Hanselmann | L{list_owned} to get the names of all owned locks
|
1009 | c6a622cf | Michael Hanselmann |
|
1010 | c6a622cf | Michael Hanselmann | """
|
1011 | c6a622cf | Michael Hanselmann | if isinstance(names, basestring): |
1012 | c6a622cf | Michael Hanselmann | names = [names] |
1013 | c6a622cf | Michael Hanselmann | |
1014 | c6a622cf | Michael Hanselmann | # Avoid check if no locks are owned anyway
|
1015 | c6a622cf | Michael Hanselmann | if names and self.is_owned(): |
1016 | c6a622cf | Michael Hanselmann | candidates = [] |
1017 | c6a622cf | Michael Hanselmann | |
1018 | c6a622cf | Michael Hanselmann | # Gather references to all locks (in case they're deleted in the meantime)
|
1019 | c6a622cf | Michael Hanselmann | for lname in names: |
1020 | c6a622cf | Michael Hanselmann | try:
|
1021 | c6a622cf | Michael Hanselmann | lock = self.__lockdict[lname]
|
1022 | c6a622cf | Michael Hanselmann | except KeyError: |
1023 | c6a622cf | Michael Hanselmann | raise errors.LockError("Non-existing lock '%s' in set '%s' (it may" |
1024 | c6a622cf | Michael Hanselmann | " have been removed)" % (lname, self.name)) |
1025 | c6a622cf | Michael Hanselmann | else:
|
1026 | c6a622cf | Michael Hanselmann | candidates.append(lock) |
1027 | c6a622cf | Michael Hanselmann | |
1028 | c6a622cf | Michael Hanselmann | return compat.all(lock.is_owned(shared=shared) for lock in candidates) |
1029 | c6a622cf | Michael Hanselmann | else:
|
1030 | c6a622cf | Michael Hanselmann | return False |
1031 | c6a622cf | Michael Hanselmann | |
1032 | b2dabfd6 | Guido Trotter | def _add_owned(self, name=None): |
1033 | aaae9bc0 | Guido Trotter | """Note the current thread owns the given lock"""
|
1034 | b2dabfd6 | Guido Trotter | if name is None: |
1035 | ee2b99e3 | Michael Hanselmann | if not self.is_owned(): |
1036 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()] = set() |
1037 | aaae9bc0 | Guido Trotter | else:
|
1038 | ee2b99e3 | Michael Hanselmann | if self.is_owned(): |
1039 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()].add(name)
|
1040 | b2dabfd6 | Guido Trotter | else:
|
1041 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()] = set([name]) |
1042 | b2dabfd6 | Guido Trotter | |
1043 | b2dabfd6 | Guido Trotter | def _del_owned(self, name=None): |
1044 | aaae9bc0 | Guido Trotter | """Note the current thread owns the given lock"""
|
1045 | aaae9bc0 | Guido Trotter | |
1046 | ee2b99e3 | Michael Hanselmann | assert not (name is None and self.__lock.is_owned()), \ |
1047 | e4335b5b | Michael Hanselmann | "Cannot hold internal lock when deleting owner status"
|
1048 | e4335b5b | Michael Hanselmann | |
1049 | b2dabfd6 | Guido Trotter | if name is not None: |
1050 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()].remove(name)
|
1051 | b2dabfd6 | Guido Trotter | |
1052 | b2dabfd6 | Guido Trotter | # Only remove the key if we don't hold the set-lock as well
|
1053 | ee2b99e3 | Michael Hanselmann | if (not self.__lock.is_owned() and |
1054 | b2dabfd6 | Guido Trotter | not self.__owners[threading.currentThread()]): |
1055 | aaae9bc0 | Guido Trotter | del self.__owners[threading.currentThread()] |
1056 | aaae9bc0 | Guido Trotter | |
1057 | ee2b99e3 | Michael Hanselmann | def list_owned(self): |
1058 | aaae9bc0 | Guido Trotter | """Get the set of resource names owned by the current thread"""
|
1059 | ee2b99e3 | Michael Hanselmann | if self.is_owned(): |
1060 | aaae9bc0 | Guido Trotter | return self.__owners[threading.currentThread()].copy() |
1061 | aaae9bc0 | Guido Trotter | else:
|
1062 | aaae9bc0 | Guido Trotter | return set() |
1063 | aaae9bc0 | Guido Trotter | |
1064 | 5aab242c | Michael Hanselmann | def _release_and_delete_owned(self): |
1065 | 5aab242c | Michael Hanselmann | """Release and delete all resources owned by the current thread"""
|
1066 | ee2b99e3 | Michael Hanselmann | for lname in self.list_owned(): |
1067 | 56452af7 | Michael Hanselmann | lock = self.__lockdict[lname]
|
1068 | ee2b99e3 | Michael Hanselmann | if lock.is_owned():
|
1069 | 56452af7 | Michael Hanselmann | lock.release() |
1070 | 5aab242c | Michael Hanselmann | self._del_owned(name=lname)
|
1071 | 5aab242c | Michael Hanselmann | |
1072 | aaae9bc0 | Guido Trotter | def __names(self): |
1073 | aaae9bc0 | Guido Trotter | """Return the current set of names.
|
1074 | aaae9bc0 | Guido Trotter |
|
1075 | aaae9bc0 | Guido Trotter | Only call this function while holding __lock and don't iterate on the
|
1076 | aaae9bc0 | Guido Trotter | result after releasing the lock.
|
1077 | aaae9bc0 | Guido Trotter |
|
1078 | aaae9bc0 | Guido Trotter | """
|
1079 | 0cf257c5 | Guido Trotter | return self.__lockdict.keys() |
1080 | aaae9bc0 | Guido Trotter | |
1081 | aaae9bc0 | Guido Trotter | def _names(self): |
1082 | aaae9bc0 | Guido Trotter | """Return a copy of the current set of elements.
|
1083 | aaae9bc0 | Guido Trotter |
|
1084 | aaae9bc0 | Guido Trotter | Used only for debugging purposes.
|
1085 | cdb08f44 | Michael Hanselmann |
|
1086 | aaae9bc0 | Guido Trotter | """
|
1087 | d4803c24 | Guido Trotter | # If we don't already own the set-level lock acquired
|
1088 | d4803c24 | Guido Trotter | # we'll get it and note we need to release it later.
|
1089 | d4803c24 | Guido Trotter | release_lock = False
|
1090 | ee2b99e3 | Michael Hanselmann | if not self.__lock.is_owned(): |
1091 | d4803c24 | Guido Trotter | release_lock = True
|
1092 | d4803c24 | Guido Trotter | self.__lock.acquire(shared=1) |
1093 | aaae9bc0 | Guido Trotter | try:
|
1094 | aaae9bc0 | Guido Trotter | result = self.__names()
|
1095 | aaae9bc0 | Guido Trotter | finally:
|
1096 | d4803c24 | Guido Trotter | if release_lock:
|
1097 | d4803c24 | Guido Trotter | self.__lock.release()
|
1098 | 0cf257c5 | Guido Trotter | return set(result) |
1099 | aaae9bc0 | Guido Trotter | |
1100 | 7100c2fa | Michael Hanselmann | def acquire(self, names, timeout=None, shared=0, priority=None, |
1101 | 887c7aa6 | Michael Hanselmann | test_notify=None):
|
1102 | aaae9bc0 | Guido Trotter | """Acquire a set of resource locks.
|
1103 | aaae9bc0 | Guido Trotter |
|
1104 | ec44d893 | Guido Trotter | @type names: list of strings (or string)
|
1105 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be acquired
|
1106 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1107 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1108 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default an
|
1109 | c41eea6e | Iustin Pop | exclusive lock will be acquired
|
1110 | 5aab242c | Michael Hanselmann | @type timeout: float or None
|
1111 | 5e0a6daf | Michael Hanselmann | @param timeout: Maximum time to acquire all locks
|
1112 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
1113 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring locks
|
1114 | 5aab242c | Michael Hanselmann | @type test_notify: callable or None
|
1115 | 5aab242c | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
1116 | aaae9bc0 | Guido Trotter |
|
1117 | 5aab242c | Michael Hanselmann | @return: Set of all locks successfully acquired or None in case of timeout
|
1118 | aaae9bc0 | Guido Trotter |
|
1119 | c41eea6e | Iustin Pop | @raise errors.LockError: when any lock we try to acquire has
|
1120 | c41eea6e | Iustin Pop | been deleted before we succeed. In this case none of the
|
1121 | c41eea6e | Iustin Pop | locks requested will be acquired.
|
1122 | aaae9bc0 | Guido Trotter |
|
1123 | aaae9bc0 | Guido Trotter | """
|
1124 | 5aab242c | Michael Hanselmann | assert timeout is None or timeout >= 0.0 |
1125 | aaae9bc0 | Guido Trotter | |
1126 | aaae9bc0 | Guido Trotter | # Check we don't already own locks at this level
|
1127 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned(), ("Cannot acquire locks in the same set twice" |
1128 | ee2b99e3 | Michael Hanselmann | " (lockset %s)" % self.name) |
1129 | aaae9bc0 | Guido Trotter | |
1130 | 7100c2fa | Michael Hanselmann | if priority is None: |
1131 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
1132 | 7100c2fa | Michael Hanselmann | |
1133 | 5aab242c | Michael Hanselmann | # We need to keep track of how long we spent waiting for a lock. The
|
1134 | 5aab242c | Michael Hanselmann | # timeout passed to this function is over all lock acquires.
|
1135 | 557838c1 | Renรฉ Nussbaumer | running_timeout = utils.RunningTimeout(timeout, False)
|
1136 | 5aab242c | Michael Hanselmann | |
1137 | 806e20fd | Guido Trotter | try:
|
1138 | 76e2f08a | Michael Hanselmann | if names is not None: |
1139 | 5aab242c | Michael Hanselmann | # Support passing in a single resource to acquire rather than many
|
1140 | 5aab242c | Michael Hanselmann | if isinstance(names, basestring): |
1141 | 5aab242c | Michael Hanselmann | names = [names] |
1142 | 5aab242c | Michael Hanselmann | |
1143 | 887c7aa6 | Michael Hanselmann | return self.__acquire_inner(names, False, shared, priority, |
1144 | 7e8841bd | Michael Hanselmann | running_timeout.Remaining, test_notify) |
1145 | 76e2f08a | Michael Hanselmann | |
1146 | 76e2f08a | Michael Hanselmann | else:
|
1147 | 76e2f08a | Michael Hanselmann | # If no names are given acquire the whole set by not letting new names
|
1148 | 76e2f08a | Michael Hanselmann | # being added before we release, and getting the current list of names.
|
1149 | 76e2f08a | Michael Hanselmann | # Some of them may then be deleted later, but we'll cope with this.
|
1150 | 76e2f08a | Michael Hanselmann | #
|
1151 | 76e2f08a | Michael Hanselmann | # We'd like to acquire this lock in a shared way, as it's nice if
|
1152 | 887c7aa6 | Michael Hanselmann | # everybody else can use the instances at the same time. If we are
|
1153 | 76e2f08a | Michael Hanselmann | # acquiring them exclusively though they won't be able to do this
|
1154 | 76e2f08a | Michael Hanselmann | # anyway, though, so we'll get the list lock exclusively as well in
|
1155 | 76e2f08a | Michael Hanselmann | # order to be able to do add() on the set while owning it.
|
1156 | 887c7aa6 | Michael Hanselmann | if not self.__lock.acquire(shared=shared, priority=priority, |
1157 | 7e8841bd | Michael Hanselmann | timeout=running_timeout.Remaining()): |
1158 | 76e2f08a | Michael Hanselmann | raise _AcquireTimeout()
|
1159 | 76e2f08a | Michael Hanselmann | try:
|
1160 | 76e2f08a | Michael Hanselmann | # note we own the set-lock
|
1161 | 76e2f08a | Michael Hanselmann | self._add_owned()
|
1162 | 76e2f08a | Michael Hanselmann | |
1163 | 887c7aa6 | Michael Hanselmann | return self.__acquire_inner(self.__names(), True, shared, priority, |
1164 | 7e8841bd | Michael Hanselmann | running_timeout.Remaining, test_notify) |
1165 | 76e2f08a | Michael Hanselmann | except:
|
1166 | 76e2f08a | Michael Hanselmann | # We shouldn't have problems adding the lock to the owners list, but
|
1167 | 76e2f08a | Michael Hanselmann | # if we did we'll try to release this lock and re-raise exception.
|
1168 | 76e2f08a | Michael Hanselmann | # Of course something is going to be really wrong, after this.
|
1169 | 5aab242c | Michael Hanselmann | self.__lock.release()
|
1170 | 76e2f08a | Michael Hanselmann | self._del_owned()
|
1171 | 76e2f08a | Michael Hanselmann | raise
|
1172 | 5aab242c | Michael Hanselmann | |
1173 | 5aab242c | Michael Hanselmann | except _AcquireTimeout:
|
1174 | 5aab242c | Michael Hanselmann | return None |
1175 | aaae9bc0 | Guido Trotter | |
1176 | 887c7aa6 | Michael Hanselmann | def __acquire_inner(self, names, want_all, shared, priority, |
1177 | 887c7aa6 | Michael Hanselmann | timeout_fn, test_notify): |
1178 | 7e8841bd | Michael Hanselmann | """Inner logic for acquiring a number of locks.
|
1179 | 7e8841bd | Michael Hanselmann |
|
1180 | 7e8841bd | Michael Hanselmann | @param names: Names of the locks to be acquired
|
1181 | 7e8841bd | Michael Hanselmann | @param want_all: Whether all locks in the set should be acquired
|
1182 | 7e8841bd | Michael Hanselmann | @param shared: Whether to acquire in shared mode
|
1183 | 7e8841bd | Michael Hanselmann | @param timeout_fn: Function returning remaining timeout
|
1184 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring locks
|
1185 | 7e8841bd | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
1186 | 76e2f08a | Michael Hanselmann |
|
1187 | 76e2f08a | Michael Hanselmann | """
|
1188 | 76e2f08a | Michael Hanselmann | acquire_list = [] |
1189 | 76e2f08a | Michael Hanselmann | |
1190 | 76e2f08a | Michael Hanselmann | # First we look the locks up on __lockdict. We have no way of being sure
|
1191 | 76e2f08a | Michael Hanselmann | # they will still be there after, but this makes it a lot faster should
|
1192 | 71e1863e | Michael Hanselmann | # just one of them be the already wrong. Using a sorted sequence to prevent
|
1193 | 71e1863e | Michael Hanselmann | # deadlocks.
|
1194 | 71e1863e | Michael Hanselmann | for lname in sorted(utils.UniqueSequence(names)): |
1195 | 76e2f08a | Michael Hanselmann | try:
|
1196 | 76e2f08a | Michael Hanselmann | lock = self.__lockdict[lname] # raises KeyError if lock is not there |
1197 | 76e2f08a | Michael Hanselmann | except KeyError: |
1198 | 76e2f08a | Michael Hanselmann | if want_all:
|
1199 | 76e2f08a | Michael Hanselmann | # We are acquiring all the set, it doesn't matter if this particular
|
1200 | 76e2f08a | Michael Hanselmann | # element is not there anymore.
|
1201 | 76e2f08a | Michael Hanselmann | continue
|
1202 | 76e2f08a | Michael Hanselmann | |
1203 | e1137eb6 | Michael Hanselmann | raise errors.LockError("Non-existing lock %s in set %s (it may have" |
1204 | e1137eb6 | Michael Hanselmann | " been removed)" % (lname, self.name)) |
1205 | 76e2f08a | Michael Hanselmann | |
1206 | 9b154270 | Michael Hanselmann | acquire_list.append((lname, lock)) |
1207 | 9b154270 | Michael Hanselmann | |
1208 | 76e2f08a | Michael Hanselmann | # This will hold the locknames we effectively acquired.
|
1209 | 76e2f08a | Michael Hanselmann | acquired = set()
|
1210 | 76e2f08a | Michael Hanselmann | |
1211 | 76e2f08a | Michael Hanselmann | try:
|
1212 | 76e2f08a | Michael Hanselmann | # Now acquire_list contains a sorted list of resources and locks we
|
1213 | 76e2f08a | Michael Hanselmann | # want. In order to get them we loop on this (private) list and
|
1214 | 76e2f08a | Michael Hanselmann | # acquire() them. We gave no real guarantee they will still exist till
|
1215 | 76e2f08a | Michael Hanselmann | # this is done but .acquire() itself is safe and will alert us if the
|
1216 | 76e2f08a | Michael Hanselmann | # lock gets deleted.
|
1217 | 76e2f08a | Michael Hanselmann | for (lname, lock) in acquire_list: |
1218 | 76e2f08a | Michael Hanselmann | if __debug__ and callable(test_notify): |
1219 | 76e2f08a | Michael Hanselmann | test_notify_fn = lambda: test_notify(lname)
|
1220 | 76e2f08a | Michael Hanselmann | else:
|
1221 | 76e2f08a | Michael Hanselmann | test_notify_fn = None
|
1222 | 76e2f08a | Michael Hanselmann | |
1223 | 76e2f08a | Michael Hanselmann | timeout = timeout_fn() |
1224 | 76e2f08a | Michael Hanselmann | |
1225 | 76e2f08a | Michael Hanselmann | try:
|
1226 | 76e2f08a | Michael Hanselmann | # raises LockError if the lock was deleted
|
1227 | 76e2f08a | Michael Hanselmann | acq_success = lock.acquire(shared=shared, timeout=timeout, |
1228 | 887c7aa6 | Michael Hanselmann | priority=priority, |
1229 | 76e2f08a | Michael Hanselmann | test_notify=test_notify_fn) |
1230 | 76e2f08a | Michael Hanselmann | except errors.LockError:
|
1231 | 76e2f08a | Michael Hanselmann | if want_all:
|
1232 | 76e2f08a | Michael Hanselmann | # We are acquiring all the set, it doesn't matter if this
|
1233 | 76e2f08a | Michael Hanselmann | # particular element is not there anymore.
|
1234 | 76e2f08a | Michael Hanselmann | continue
|
1235 | 76e2f08a | Michael Hanselmann | |
1236 | e1137eb6 | Michael Hanselmann | raise errors.LockError("Non-existing lock %s in set %s (it may" |
1237 | e1137eb6 | Michael Hanselmann | " have been removed)" % (lname, self.name)) |
1238 | 76e2f08a | Michael Hanselmann | |
1239 | 76e2f08a | Michael Hanselmann | if not acq_success: |
1240 | 76e2f08a | Michael Hanselmann | # Couldn't get lock or timeout occurred
|
1241 | 76e2f08a | Michael Hanselmann | if timeout is None: |
1242 | 76e2f08a | Michael Hanselmann | # This shouldn't happen as SharedLock.acquire(timeout=None) is
|
1243 | 76e2f08a | Michael Hanselmann | # blocking.
|
1244 | 7f93570a | Iustin Pop | raise errors.LockError("Failed to get lock %s (set %s)" % |
1245 | 7f93570a | Iustin Pop | (lname, self.name))
|
1246 | 76e2f08a | Michael Hanselmann | |
1247 | 76e2f08a | Michael Hanselmann | raise _AcquireTimeout()
|
1248 | 76e2f08a | Michael Hanselmann | |
1249 | 76e2f08a | Michael Hanselmann | try:
|
1250 | 76e2f08a | Michael Hanselmann | # now the lock cannot be deleted, we have it!
|
1251 | 76e2f08a | Michael Hanselmann | self._add_owned(name=lname)
|
1252 | 76e2f08a | Michael Hanselmann | acquired.add(lname) |
1253 | 76e2f08a | Michael Hanselmann | |
1254 | 76e2f08a | Michael Hanselmann | except:
|
1255 | 76e2f08a | Michael Hanselmann | # We shouldn't have problems adding the lock to the owners list, but
|
1256 | 76e2f08a | Michael Hanselmann | # if we did we'll try to release this lock and re-raise exception.
|
1257 | 76e2f08a | Michael Hanselmann | # Of course something is going to be really wrong after this.
|
1258 | ee2b99e3 | Michael Hanselmann | if lock.is_owned():
|
1259 | 76e2f08a | Michael Hanselmann | lock.release() |
1260 | 76e2f08a | Michael Hanselmann | raise
|
1261 | 76e2f08a | Michael Hanselmann | |
1262 | 76e2f08a | Michael Hanselmann | except:
|
1263 | 76e2f08a | Michael Hanselmann | # Release all owned locks
|
1264 | 76e2f08a | Michael Hanselmann | self._release_and_delete_owned()
|
1265 | 76e2f08a | Michael Hanselmann | raise
|
1266 | 76e2f08a | Michael Hanselmann | |
1267 | 0cc00929 | Guido Trotter | return acquired
|
1268 | aaae9bc0 | Guido Trotter | |
1269 | 3dbe3ddf | Michael Hanselmann | def downgrade(self, names=None): |
1270 | 3dbe3ddf | Michael Hanselmann | """Downgrade a set of resource locks from exclusive to shared mode.
|
1271 | 3dbe3ddf | Michael Hanselmann |
|
1272 | 3dbe3ddf | Michael Hanselmann | The locks must have been acquired in exclusive mode.
|
1273 | 3dbe3ddf | Michael Hanselmann |
|
1274 | 3dbe3ddf | Michael Hanselmann | """
|
1275 | ee2b99e3 | Michael Hanselmann | assert self.is_owned(), ("downgrade on lockset %s while not owning any" |
1276 | ee2b99e3 | Michael Hanselmann | " lock" % self.name) |
1277 | 3dbe3ddf | Michael Hanselmann | |
1278 | 3dbe3ddf | Michael Hanselmann | # Support passing in a single resource to downgrade rather than many
|
1279 | 3dbe3ddf | Michael Hanselmann | if isinstance(names, basestring): |
1280 | 3dbe3ddf | Michael Hanselmann | names = [names] |
1281 | 3dbe3ddf | Michael Hanselmann | |
1282 | ee2b99e3 | Michael Hanselmann | owned = self.list_owned()
|
1283 | 3dbe3ddf | Michael Hanselmann | |
1284 | 3dbe3ddf | Michael Hanselmann | if names is None: |
1285 | 3dbe3ddf | Michael Hanselmann | names = owned |
1286 | 3dbe3ddf | Michael Hanselmann | else:
|
1287 | 3dbe3ddf | Michael Hanselmann | names = set(names)
|
1288 | 3dbe3ddf | Michael Hanselmann | assert owned.issuperset(names), \
|
1289 | 3dbe3ddf | Michael Hanselmann | ("downgrade() on unheld resources %s (set %s)" %
|
1290 | 3dbe3ddf | Michael Hanselmann | (names.difference(owned), self.name))
|
1291 | 3dbe3ddf | Michael Hanselmann | |
1292 | 3dbe3ddf | Michael Hanselmann | for lockname in names: |
1293 | 3dbe3ddf | Michael Hanselmann | self.__lockdict[lockname].downgrade()
|
1294 | 3dbe3ddf | Michael Hanselmann | |
1295 | 3dbe3ddf | Michael Hanselmann | # Do we own the lockset in exclusive mode?
|
1296 | ee2b99e3 | Michael Hanselmann | if self.__lock.is_owned(shared=0): |
1297 | 3dbe3ddf | Michael Hanselmann | # Have all locks been downgraded?
|
1298 | ee2b99e3 | Michael Hanselmann | if not compat.any(lock.is_owned(shared=0) |
1299 | 3dbe3ddf | Michael Hanselmann | for lock in self.__lockdict.values()): |
1300 | 3dbe3ddf | Michael Hanselmann | self.__lock.downgrade()
|
1301 | ee2b99e3 | Michael Hanselmann | assert self.__lock.is_owned(shared=1) |
1302 | 3dbe3ddf | Michael Hanselmann | |
1303 | 3dbe3ddf | Michael Hanselmann | return True |
1304 | 3dbe3ddf | Michael Hanselmann | |
1305 | aaae9bc0 | Guido Trotter | def release(self, names=None): |
1306 | aaae9bc0 | Guido Trotter | """Release a set of resource locks, at the same level.
|
1307 | aaae9bc0 | Guido Trotter |
|
1308 | aaae9bc0 | Guido Trotter | You must have acquired the locks, either in shared or in exclusive mode,
|
1309 | aaae9bc0 | Guido Trotter | before releasing them.
|
1310 | aaae9bc0 | Guido Trotter |
|
1311 | ec44d893 | Guido Trotter | @type names: list of strings, or None
|
1312 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be released
|
1313 | c41eea6e | Iustin Pop | (defaults to all the locks acquired at that level).
|
1314 | aaae9bc0 | Guido Trotter |
|
1315 | aaae9bc0 | Guido Trotter | """
|
1316 | ee2b99e3 | Michael Hanselmann | assert self.is_owned(), ("release() on lock set %s while not owner" % |
1317 | ee2b99e3 | Michael Hanselmann | self.name)
|
1318 | aaae9bc0 | Guido Trotter | |
1319 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to release rather than many
|
1320 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1321 | aaae9bc0 | Guido Trotter | names = [names] |
1322 | aaae9bc0 | Guido Trotter | |
1323 | aaae9bc0 | Guido Trotter | if names is None: |
1324 | ee2b99e3 | Michael Hanselmann | names = self.list_owned()
|
1325 | aaae9bc0 | Guido Trotter | else:
|
1326 | aaae9bc0 | Guido Trotter | names = set(names)
|
1327 | ee2b99e3 | Michael Hanselmann | assert self.list_owned().issuperset(names), ( |
1328 | 7f93570a | Iustin Pop | "release() on unheld resources %s (set %s)" %
|
1329 | ee2b99e3 | Michael Hanselmann | (names.difference(self.list_owned()), self.name)) |
1330 | aaae9bc0 | Guido Trotter | |
1331 | 3b7ed473 | Guido Trotter | # First of all let's release the "all elements" lock, if set.
|
1332 | 3b7ed473 | Guido Trotter | # After this 'add' can work again
|
1333 | ee2b99e3 | Michael Hanselmann | if self.__lock.is_owned(): |
1334 | 3b7ed473 | Guido Trotter | self.__lock.release()
|
1335 | b2dabfd6 | Guido Trotter | self._del_owned()
|
1336 | 3b7ed473 | Guido Trotter | |
1337 | aaae9bc0 | Guido Trotter | for lockname in names: |
1338 | aaae9bc0 | Guido Trotter | # If we are sure the lock doesn't leave __lockdict without being
|
1339 | aaae9bc0 | Guido Trotter | # exclusively held we can do this...
|
1340 | aaae9bc0 | Guido Trotter | self.__lockdict[lockname].release()
|
1341 | b2dabfd6 | Guido Trotter | self._del_owned(name=lockname)
|
1342 | aaae9bc0 | Guido Trotter | |
1343 | aaae9bc0 | Guido Trotter | def add(self, names, acquired=0, shared=0): |
1344 | aaae9bc0 | Guido Trotter | """Add a new set of elements to the set
|
1345 | aaae9bc0 | Guido Trotter |
|
1346 | ec44d893 | Guido Trotter | @type names: list of strings
|
1347 | c41eea6e | Iustin Pop | @param names: names of the new elements to add
|
1348 | ec44d893 | Guido Trotter | @type acquired: integer (0/1) used as a boolean
|
1349 | c41eea6e | Iustin Pop | @param acquired: pre-acquire the new resource?
|
1350 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1351 | c41eea6e | Iustin Pop | @param shared: is the pre-acquisition shared?
|
1352 | aaae9bc0 | Guido Trotter |
|
1353 | aaae9bc0 | Guido Trotter | """
|
1354 | d2aff862 | Guido Trotter | # Check we don't already own locks at this level
|
1355 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned() or self.__lock.is_owned(shared=0), \ |
1356 | 7f93570a | Iustin Pop | ("Cannot add locks if the set %s is only partially owned, or shared" %
|
1357 | 7f93570a | Iustin Pop | self.name)
|
1358 | 3b7ed473 | Guido Trotter | |
1359 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to add rather than many
|
1360 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1361 | aaae9bc0 | Guido Trotter | names = [names] |
1362 | aaae9bc0 | Guido Trotter | |
1363 | ab62526c | Guido Trotter | # If we don't already own the set-level lock acquired in an exclusive way
|
1364 | 3b7ed473 | Guido Trotter | # we'll get it and note we need to release it later.
|
1365 | 3b7ed473 | Guido Trotter | release_lock = False
|
1366 | ee2b99e3 | Michael Hanselmann | if not self.__lock.is_owned(): |
1367 | 3b7ed473 | Guido Trotter | release_lock = True
|
1368 | 3b7ed473 | Guido Trotter | self.__lock.acquire()
|
1369 | 3b7ed473 | Guido Trotter | |
1370 | aaae9bc0 | Guido Trotter | try:
|
1371 | 0cf257c5 | Guido Trotter | invalid_names = set(self.__names()).intersection(names) |
1372 | aaae9bc0 | Guido Trotter | if invalid_names:
|
1373 | aaae9bc0 | Guido Trotter | # This must be an explicit raise, not an assert, because assert is
|
1374 | aaae9bc0 | Guido Trotter | # turned off when using optimization, and this can happen because of
|
1375 | aaae9bc0 | Guido Trotter | # concurrency even if the user doesn't want it.
|
1376 | 7f93570a | Iustin Pop | raise errors.LockError("duplicate add(%s) on lockset %s" % |
1377 | 7f93570a | Iustin Pop | (invalid_names, self.name))
|
1378 | aaae9bc0 | Guido Trotter | |
1379 | aaae9bc0 | Guido Trotter | for lockname in names: |
1380 | 19b9ba9a | Michael Hanselmann | lock = SharedLock(self._GetLockName(lockname), monitor=self.__monitor) |
1381 | aaae9bc0 | Guido Trotter | |
1382 | aaae9bc0 | Guido Trotter | if acquired:
|
1383 | 887c7aa6 | Michael Hanselmann | # No need for priority or timeout here as this lock has just been
|
1384 | 887c7aa6 | Michael Hanselmann | # created
|
1385 | aaae9bc0 | Guido Trotter | lock.acquire(shared=shared) |
1386 | aaae9bc0 | Guido Trotter | # now the lock cannot be deleted, we have it!
|
1387 | aaae9bc0 | Guido Trotter | try:
|
1388 | b2dabfd6 | Guido Trotter | self._add_owned(name=lockname)
|
1389 | aaae9bc0 | Guido Trotter | except:
|
1390 | aaae9bc0 | Guido Trotter | # We shouldn't have problems adding the lock to the owners list,
|
1391 | aaae9bc0 | Guido Trotter | # but if we did we'll try to release this lock and re-raise
|
1392 | aaae9bc0 | Guido Trotter | # exception. Of course something is going to be really wrong,
|
1393 | aaae9bc0 | Guido Trotter | # after this. On the other hand the lock hasn't been added to the
|
1394 | aaae9bc0 | Guido Trotter | # __lockdict yet so no other threads should be pending on it. This
|
1395 | aaae9bc0 | Guido Trotter | # release is just a safety measure.
|
1396 | aaae9bc0 | Guido Trotter | lock.release() |
1397 | aaae9bc0 | Guido Trotter | raise
|
1398 | aaae9bc0 | Guido Trotter | |
1399 | aaae9bc0 | Guido Trotter | self.__lockdict[lockname] = lock
|
1400 | aaae9bc0 | Guido Trotter | |
1401 | aaae9bc0 | Guido Trotter | finally:
|
1402 | 3b7ed473 | Guido Trotter | # Only release __lock if we were not holding it previously.
|
1403 | 3b7ed473 | Guido Trotter | if release_lock:
|
1404 | 3b7ed473 | Guido Trotter | self.__lock.release()
|
1405 | aaae9bc0 | Guido Trotter | |
1406 | aaae9bc0 | Guido Trotter | return True |
1407 | aaae9bc0 | Guido Trotter | |
1408 | 5e0a6daf | Michael Hanselmann | def remove(self, names): |
1409 | aaae9bc0 | Guido Trotter | """Remove elements from the lock set.
|
1410 | aaae9bc0 | Guido Trotter |
|
1411 | aaae9bc0 | Guido Trotter | You can either not hold anything in the lockset or already hold a superset
|
1412 | aaae9bc0 | Guido Trotter | of the elements you want to delete, exclusively.
|
1413 | aaae9bc0 | Guido Trotter |
|
1414 | ec44d893 | Guido Trotter | @type names: list of strings
|
1415 | c41eea6e | Iustin Pop | @param names: names of the resource to remove.
|
1416 | aaae9bc0 | Guido Trotter |
|
1417 | 5aab242c | Michael Hanselmann | @return: a list of locks which we removed; the list is always
|
1418 | c41eea6e | Iustin Pop | equal to the names list if we were holding all the locks
|
1419 | c41eea6e | Iustin Pop | exclusively
|
1420 | aaae9bc0 | Guido Trotter |
|
1421 | aaae9bc0 | Guido Trotter | """
|
1422 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to remove rather than many
|
1423 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1424 | aaae9bc0 | Guido Trotter | names = [names] |
1425 | aaae9bc0 | Guido Trotter | |
1426 | aaae9bc0 | Guido Trotter | # If we own any subset of this lock it must be a superset of what we want
|
1427 | aaae9bc0 | Guido Trotter | # to delete. The ownership must also be exclusive, but that will be checked
|
1428 | aaae9bc0 | Guido Trotter | # by the lock itself.
|
1429 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned() or self.list_owned().issuperset(names), ( |
1430 | 7f93570a | Iustin Pop | "remove() on acquired lockset %s while not owning all elements" %
|
1431 | 7f93570a | Iustin Pop | self.name)
|
1432 | aaae9bc0 | Guido Trotter | |
1433 | 3f404fc5 | Guido Trotter | removed = [] |
1434 | aaae9bc0 | Guido Trotter | |
1435 | aaae9bc0 | Guido Trotter | for lname in names: |
1436 | aaae9bc0 | Guido Trotter | # Calling delete() acquires the lock exclusively if we don't already own
|
1437 | aaae9bc0 | Guido Trotter | # it, and causes all pending and subsequent lock acquires to fail. It's
|
1438 | aaae9bc0 | Guido Trotter | # fine to call it out of order because delete() also implies release(),
|
1439 | aaae9bc0 | Guido Trotter | # and the assertion above guarantees that if we either already hold
|
1440 | aaae9bc0 | Guido Trotter | # everything we want to delete, or we hold none.
|
1441 | aaae9bc0 | Guido Trotter | try:
|
1442 | aaae9bc0 | Guido Trotter | self.__lockdict[lname].delete()
|
1443 | 3f404fc5 | Guido Trotter | removed.append(lname) |
1444 | aaae9bc0 | Guido Trotter | except (KeyError, errors.LockError): |
1445 | aaae9bc0 | Guido Trotter | # This cannot happen if we were already holding it, verify:
|
1446 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned(), ("remove failed while holding lockset %s" % |
1447 | ee2b99e3 | Michael Hanselmann | self.name)
|
1448 | aaae9bc0 | Guido Trotter | else:
|
1449 | aaae9bc0 | Guido Trotter | # If no LockError was raised we are the ones who deleted the lock.
|
1450 | aaae9bc0 | Guido Trotter | # This means we can safely remove it from lockdict, as any further or
|
1451 | aaae9bc0 | Guido Trotter | # pending delete() or acquire() will fail (and nobody can have the lock
|
1452 | aaae9bc0 | Guido Trotter | # since before our call to delete()).
|
1453 | aaae9bc0 | Guido Trotter | #
|
1454 | aaae9bc0 | Guido Trotter | # This is done in an else clause because if the exception was thrown
|
1455 | aaae9bc0 | Guido Trotter | # it's the job of the one who actually deleted it.
|
1456 | aaae9bc0 | Guido Trotter | del self.__lockdict[lname] |
1457 | aaae9bc0 | Guido Trotter | # And let's remove it from our private list if we owned it.
|
1458 | ee2b99e3 | Michael Hanselmann | if self.is_owned(): |
1459 | b2dabfd6 | Guido Trotter | self._del_owned(name=lname)
|
1460 | aaae9bc0 | Guido Trotter | |
1461 | 3f404fc5 | Guido Trotter | return removed
|
1462 | aaae9bc0 | Guido Trotter | |
1463 | 7ee7c0c7 | Guido Trotter | |
1464 | 7ee7c0c7 | Guido Trotter | # Locking levels, must be acquired in increasing order.
|
1465 | 7ee7c0c7 | Guido Trotter | # Current rules are:
|
1466 | 7ee7c0c7 | Guido Trotter | # - at level LEVEL_CLUSTER resides the Big Ganeti Lock (BGL) which must be
|
1467 | 7ee7c0c7 | Guido Trotter | # acquired before performing any operation, either in shared or in exclusive
|
1468 | 7ee7c0c7 | Guido Trotter | # mode. acquiring the BGL in exclusive mode is discouraged and should be
|
1469 | 7ee7c0c7 | Guido Trotter | # avoided.
|
1470 | 7ee7c0c7 | Guido Trotter | # - at levels LEVEL_NODE and LEVEL_INSTANCE reside node and instance locks.
|
1471 | 7ee7c0c7 | Guido Trotter | # If you need more than one node, or more than one instance, acquire them at
|
1472 | 7ee7c0c7 | Guido Trotter | # the same time.
|
1473 | 7ee7c0c7 | Guido Trotter | LEVEL_CLUSTER = 0
|
1474 | 04e1bfaf | Guido Trotter | LEVEL_INSTANCE = 1
|
1475 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP = 2
|
1476 | 819ca990 | Guido Trotter | LEVEL_NODE = 3
|
1477 | e02ee261 | Helga Velroyen | #: Level for node resources, used for operations with possibly high impact on
|
1478 | e02ee261 | Helga Velroyen | #: the node's disks.
|
1479 | 4e070776 | Michael Hanselmann | LEVEL_NODE_RES = 4
|
1480 | 7ee7c0c7 | Guido Trotter | |
1481 | 4e070776 | Michael Hanselmann | LEVELS = [ |
1482 | 4e070776 | Michael Hanselmann | LEVEL_CLUSTER, |
1483 | 4e070776 | Michael Hanselmann | LEVEL_INSTANCE, |
1484 | 4e070776 | Michael Hanselmann | LEVEL_NODEGROUP, |
1485 | 4e070776 | Michael Hanselmann | LEVEL_NODE, |
1486 | 4e070776 | Michael Hanselmann | LEVEL_NODE_RES, |
1487 | 4e070776 | Michael Hanselmann | ] |
1488 | 7ee7c0c7 | Guido Trotter | |
1489 | 7ee7c0c7 | Guido Trotter | # Lock levels which are modifiable
|
1490 | 4e070776 | Michael Hanselmann | LEVELS_MOD = frozenset([
|
1491 | 4e070776 | Michael Hanselmann | LEVEL_NODE_RES, |
1492 | 4e070776 | Michael Hanselmann | LEVEL_NODE, |
1493 | 4e070776 | Michael Hanselmann | LEVEL_NODEGROUP, |
1494 | 4e070776 | Michael Hanselmann | LEVEL_INSTANCE, |
1495 | 4e070776 | Michael Hanselmann | ]) |
1496 | 7ee7c0c7 | Guido Trotter | |
1497 | 5d7a899e | Michael Hanselmann | #: Lock level names (make sure to use singular form)
|
1498 | ea205dbc | Michael Hanselmann | LEVEL_NAMES = { |
1499 | ea205dbc | Michael Hanselmann | LEVEL_CLUSTER: "cluster",
|
1500 | ea205dbc | Michael Hanselmann | LEVEL_INSTANCE: "instance",
|
1501 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP: "nodegroup",
|
1502 | ea205dbc | Michael Hanselmann | LEVEL_NODE: "node",
|
1503 | 5d7a899e | Michael Hanselmann | LEVEL_NODE_RES: "node-res",
|
1504 | ea205dbc | Michael Hanselmann | } |
1505 | ea205dbc | Michael Hanselmann | |
1506 | 08a6c581 | Guido Trotter | # Constant for the big ganeti lock
|
1507 | 3ccb3a64 | Michael Hanselmann | BGL = "BGL"
|
1508 | 7ee7c0c7 | Guido Trotter | |
1509 | 7ee7c0c7 | Guido Trotter | |
1510 | 7ee7c0c7 | Guido Trotter | class GanetiLockManager: |
1511 | 7ee7c0c7 | Guido Trotter | """The Ganeti Locking Library
|
1512 | 7ee7c0c7 | Guido Trotter |
|
1513 | 5bbd3f7f | Michael Hanselmann | The purpose of this small library is to manage locking for ganeti clusters
|
1514 | 7ee7c0c7 | Guido Trotter | in a central place, while at the same time doing dynamic checks against
|
1515 | 7ee7c0c7 | Guido Trotter | possible deadlocks. It will also make it easier to transition to a different
|
1516 | 7ee7c0c7 | Guido Trotter | lock type should we migrate away from python threads.
|
1517 | 7ee7c0c7 | Guido Trotter |
|
1518 | 7ee7c0c7 | Guido Trotter | """
|
1519 | 7ee7c0c7 | Guido Trotter | _instance = None
|
1520 | 7ee7c0c7 | Guido Trotter | |
1521 | 819ca990 | Guido Trotter | def __init__(self, nodes, nodegroups, instances): |
1522 | 7ee7c0c7 | Guido Trotter | """Constructs a new GanetiLockManager object.
|
1523 | 7ee7c0c7 | Guido Trotter |
|
1524 | 4e07ec8c | Guido Trotter | There should be only a GanetiLockManager object at any time, so this
|
1525 | 4e07ec8c | Guido Trotter | function raises an error if this is not the case.
|
1526 | 7ee7c0c7 | Guido Trotter |
|
1527 | c41eea6e | Iustin Pop | @param nodes: list of node names
|
1528 | 819ca990 | Guido Trotter | @param nodegroups: list of nodegroup uuids
|
1529 | c41eea6e | Iustin Pop | @param instances: list of instance names
|
1530 | 7ee7c0c7 | Guido Trotter |
|
1531 | 7ee7c0c7 | Guido Trotter | """
|
1532 | c41eea6e | Iustin Pop | assert self.__class__._instance is None, \ |
1533 | c41eea6e | Iustin Pop | "double GanetiLockManager instance"
|
1534 | c41eea6e | Iustin Pop | |
1535 | 7ee7c0c7 | Guido Trotter | self.__class__._instance = self |
1536 | 7ee7c0c7 | Guido Trotter | |
1537 | 19b9ba9a | Michael Hanselmann | self._monitor = LockMonitor()
|
1538 | 19b9ba9a | Michael Hanselmann | |
1539 | 7ee7c0c7 | Guido Trotter | # The keyring contains all the locks, at their level and in the correct
|
1540 | 7ee7c0c7 | Guido Trotter | # locking order.
|
1541 | 7ee7c0c7 | Guido Trotter | self.__keyring = {
|
1542 | 5d7a899e | Michael Hanselmann | LEVEL_CLUSTER: LockSet([BGL], "cluster", monitor=self._monitor), |
1543 | 5d7a899e | Michael Hanselmann | LEVEL_NODE: LockSet(nodes, "node", monitor=self._monitor), |
1544 | 5d7a899e | Michael Hanselmann | LEVEL_NODE_RES: LockSet(nodes, "node-res", monitor=self._monitor), |
1545 | 5d7a899e | Michael Hanselmann | LEVEL_NODEGROUP: LockSet(nodegroups, "nodegroup", monitor=self._monitor), |
1546 | 5d7a899e | Michael Hanselmann | LEVEL_INSTANCE: LockSet(instances, "instance",
|
1547 | 19b9ba9a | Michael Hanselmann | monitor=self._monitor),
|
1548 | 19b9ba9a | Michael Hanselmann | } |
1549 | 19b9ba9a | Michael Hanselmann | |
1550 | 5d7a899e | Michael Hanselmann | assert compat.all(ls.name == LEVEL_NAMES[level]
|
1551 | 5d7a899e | Michael Hanselmann | for (level, ls) in self.__keyring.items()) |
1552 | 5d7a899e | Michael Hanselmann | |
1553 | 4c03b2b5 | Michael Hanselmann | def AddToLockMonitor(self, provider): |
1554 | 4c03b2b5 | Michael Hanselmann | """Registers a new lock with the monitor.
|
1555 | 4c03b2b5 | Michael Hanselmann |
|
1556 | 4c03b2b5 | Michael Hanselmann | See L{LockMonitor.RegisterLock}.
|
1557 | 4c03b2b5 | Michael Hanselmann |
|
1558 | 4c03b2b5 | Michael Hanselmann | """
|
1559 | 4c03b2b5 | Michael Hanselmann | return self._monitor.RegisterLock(provider) |
1560 | 4c03b2b5 | Michael Hanselmann | |
1561 | 24d16f76 | Michael Hanselmann | def QueryLocks(self, fields): |
1562 | 19b9ba9a | Michael Hanselmann | """Queries information from all locks.
|
1563 | 19b9ba9a | Michael Hanselmann |
|
1564 | 19b9ba9a | Michael Hanselmann | See L{LockMonitor.QueryLocks}.
|
1565 | 19b9ba9a | Michael Hanselmann |
|
1566 | 19b9ba9a | Michael Hanselmann | """
|
1567 | 24d16f76 | Michael Hanselmann | return self._monitor.QueryLocks(fields) |
1568 | 24d16f76 | Michael Hanselmann | |
1569 | 7ee7c0c7 | Guido Trotter | def _names(self, level): |
1570 | 7ee7c0c7 | Guido Trotter | """List the lock names at the given level.
|
1571 | 7ee7c0c7 | Guido Trotter |
|
1572 | c41eea6e | Iustin Pop | This can be used for debugging/testing purposes.
|
1573 | c41eea6e | Iustin Pop |
|
1574 | c41eea6e | Iustin Pop | @param level: the level whose list of locks to get
|
1575 | 7ee7c0c7 | Guido Trotter |
|
1576 | 7ee7c0c7 | Guido Trotter | """
|
1577 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1578 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level]._names() |
1579 | 7ee7c0c7 | Guido Trotter | |
1580 | ee2b99e3 | Michael Hanselmann | def is_owned(self, level): |
1581 | 7ee7c0c7 | Guido Trotter | """Check whether we are owning locks at the given level
|
1582 | 7ee7c0c7 | Guido Trotter |
|
1583 | 7ee7c0c7 | Guido Trotter | """
|
1584 | ee2b99e3 | Michael Hanselmann | return self.__keyring[level].is_owned() |
1585 | 7ee7c0c7 | Guido Trotter | |
1586 | ee2b99e3 | Michael Hanselmann | def list_owned(self, level): |
1587 | 7ee7c0c7 | Guido Trotter | """Get the set of owned locks at the given level
|
1588 | 7ee7c0c7 | Guido Trotter |
|
1589 | 7ee7c0c7 | Guido Trotter | """
|
1590 | ee2b99e3 | Michael Hanselmann | return self.__keyring[level].list_owned() |
1591 | 07cba1bc | Michael Hanselmann | |
1592 | c6a622cf | Michael Hanselmann | def check_owned(self, level, names, shared=-1): |
1593 | c6a622cf | Michael Hanselmann | """Check if locks at a certain level are owned in a specific mode.
|
1594 | c6a622cf | Michael Hanselmann |
|
1595 | c6a622cf | Michael Hanselmann | @see: L{LockSet.check_owned}
|
1596 | c6a622cf | Michael Hanselmann |
|
1597 | c6a622cf | Michael Hanselmann | """
|
1598 | c6a622cf | Michael Hanselmann | return self.__keyring[level].check_owned(names, shared=shared) |
1599 | c6a622cf | Michael Hanselmann | |
1600 | 7ee7c0c7 | Guido Trotter | def _upper_owned(self, level): |
1601 | 7ee7c0c7 | Guido Trotter | """Check that we don't own any lock at a level greater than the given one.
|
1602 | 7ee7c0c7 | Guido Trotter |
|
1603 | 7ee7c0c7 | Guido Trotter | """
|
1604 | 7ee7c0c7 | Guido Trotter | # This way of checking only works if LEVELS[i] = i, which we check for in
|
1605 | 7ee7c0c7 | Guido Trotter | # the test cases.
|
1606 | ee2b99e3 | Michael Hanselmann | return compat.any((self.is_owned(l) for l in LEVELS[level + 1:])) |
1607 | 7ee7c0c7 | Guido Trotter | |
1608 | b459a848 | Andrea Spadaccini | def _BGL_owned(self): # pylint: disable=C0103 |
1609 | 7ee7c0c7 | Guido Trotter | """Check if the current thread owns the BGL.
|
1610 | 7ee7c0c7 | Guido Trotter |
|
1611 | 7ee7c0c7 | Guido Trotter | Both an exclusive or a shared acquisition work.
|
1612 | 7ee7c0c7 | Guido Trotter |
|
1613 | 7ee7c0c7 | Guido Trotter | """
|
1614 | ee2b99e3 | Michael Hanselmann | return BGL in self.__keyring[LEVEL_CLUSTER].list_owned() |
1615 | 7ee7c0c7 | Guido Trotter | |
1616 | c70d2d9b | Iustin Pop | @staticmethod
|
1617 | b459a848 | Andrea Spadaccini | def _contains_BGL(level, names): # pylint: disable=C0103 |
1618 | c41eea6e | Iustin Pop | """Check if the level contains the BGL.
|
1619 | c41eea6e | Iustin Pop |
|
1620 | c41eea6e | Iustin Pop | Check if acting on the given level and set of names will change
|
1621 | c41eea6e | Iustin Pop | the status of the Big Ganeti Lock.
|
1622 | 7ee7c0c7 | Guido Trotter |
|
1623 | 7ee7c0c7 | Guido Trotter | """
|
1624 | 7ee7c0c7 | Guido Trotter | return level == LEVEL_CLUSTER and (names is None or BGL in names) |
1625 | 7ee7c0c7 | Guido Trotter | |
1626 | b30d95b6 | Michael Hanselmann | def acquire(self, level, names, timeout=None, shared=0, priority=None): |
1627 | 7ee7c0c7 | Guido Trotter | """Acquire a set of resource locks, at the same level.
|
1628 | 7ee7c0c7 | Guido Trotter |
|
1629 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS
|
1630 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be acquired
|
1631 | ec44d893 | Guido Trotter | @type names: list of strings (or string)
|
1632 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be acquired
|
1633 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1634 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1635 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default
|
1636 | c41eea6e | Iustin Pop | an exclusive lock will be acquired
|
1637 | 5e0a6daf | Michael Hanselmann | @type timeout: float
|
1638 | 5e0a6daf | Michael Hanselmann | @param timeout: Maximum time to acquire all locks
|
1639 | b30d95b6 | Michael Hanselmann | @type priority: integer
|
1640 | b30d95b6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
1641 | 7ee7c0c7 | Guido Trotter |
|
1642 | 7ee7c0c7 | Guido Trotter | """
|
1643 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1644 | 7ee7c0c7 | Guido Trotter | |
1645 | 7ee7c0c7 | Guido Trotter | # Check that we are either acquiring the Big Ganeti Lock or we already own
|
1646 | 7ee7c0c7 | Guido Trotter | # it. Some "legacy" opcodes need to be sure they are run non-concurrently
|
1647 | 7ee7c0c7 | Guido Trotter | # so even if we've migrated we need to at least share the BGL to be
|
1648 | 7ee7c0c7 | Guido Trotter | # compatible with them. Of course if we own the BGL exclusively there's no
|
1649 | 7ee7c0c7 | Guido Trotter | # point in acquiring any other lock, unless perhaps we are half way through
|
1650 | 7ee7c0c7 | Guido Trotter | # the migration of the current opcode.
|
1651 | 7ee7c0c7 | Guido Trotter | assert (self._contains_BGL(level, names) or self._BGL_owned()), ( |
1652 | 5ae4945a | Iustin Pop | "You must own the Big Ganeti Lock before acquiring any other")
|
1653 | 7ee7c0c7 | Guido Trotter | |
1654 | 7ee7c0c7 | Guido Trotter | # Check we don't own locks at the same or upper levels.
|
1655 | 21a6c826 | Guido Trotter | assert not self._upper_owned(level), ("Cannot acquire locks at a level" |
1656 | 5ae4945a | Iustin Pop | " while owning some at a greater one")
|
1657 | 7ee7c0c7 | Guido Trotter | |
1658 | 7ee7c0c7 | Guido Trotter | # Acquire the locks in the set.
|
1659 | b30d95b6 | Michael Hanselmann | return self.__keyring[level].acquire(names, shared=shared, timeout=timeout, |
1660 | b30d95b6 | Michael Hanselmann | priority=priority) |
1661 | 7ee7c0c7 | Guido Trotter | |
1662 | 3dbe3ddf | Michael Hanselmann | def downgrade(self, level, names=None): |
1663 | 3dbe3ddf | Michael Hanselmann | """Downgrade a set of resource locks from exclusive to shared mode.
|
1664 | 3dbe3ddf | Michael Hanselmann |
|
1665 | 3dbe3ddf | Michael Hanselmann | You must have acquired the locks in exclusive mode.
|
1666 | 3dbe3ddf | Michael Hanselmann |
|
1667 | 3dbe3ddf | Michael Hanselmann | @type level: member of locking.LEVELS
|
1668 | 3dbe3ddf | Michael Hanselmann | @param level: the level at which the locks shall be downgraded
|
1669 | 3dbe3ddf | Michael Hanselmann | @type names: list of strings, or None
|
1670 | 3dbe3ddf | Michael Hanselmann | @param names: the names of the locks which shall be downgraded
|
1671 | 3dbe3ddf | Michael Hanselmann | (defaults to all the locks acquired at the level)
|
1672 | 3dbe3ddf | Michael Hanselmann |
|
1673 | 3dbe3ddf | Michael Hanselmann | """
|
1674 | 3dbe3ddf | Michael Hanselmann | assert level in LEVELS, "Invalid locking level %s" % level |
1675 | 3dbe3ddf | Michael Hanselmann | |
1676 | 3dbe3ddf | Michael Hanselmann | return self.__keyring[level].downgrade(names=names) |
1677 | 3dbe3ddf | Michael Hanselmann | |
1678 | 7ee7c0c7 | Guido Trotter | def release(self, level, names=None): |
1679 | 7ee7c0c7 | Guido Trotter | """Release a set of resource locks, at the same level.
|
1680 | 7ee7c0c7 | Guido Trotter |
|
1681 | c41eea6e | Iustin Pop | You must have acquired the locks, either in shared or in exclusive
|
1682 | c41eea6e | Iustin Pop | mode, before releasing them.
|
1683 | 7ee7c0c7 | Guido Trotter |
|
1684 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS
|
1685 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be released
|
1686 | ec44d893 | Guido Trotter | @type names: list of strings, or None
|
1687 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be released
|
1688 | c41eea6e | Iustin Pop | (defaults to all the locks acquired at that level)
|
1689 | 7ee7c0c7 | Guido Trotter |
|
1690 | 7ee7c0c7 | Guido Trotter | """
|
1691 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1692 | 7ee7c0c7 | Guido Trotter | assert (not self._contains_BGL(level, names) or |
1693 | 7ee7c0c7 | Guido Trotter | not self._upper_owned(LEVEL_CLUSTER)), ( |
1694 | 5ae4945a | Iustin Pop | "Cannot release the Big Ganeti Lock while holding something"
|
1695 | 5ae4945a | Iustin Pop | " at upper levels (%r)" %
|
1696 | 5ae4945a | Iustin Pop | (utils.CommaJoin(["%s=%r" % (LEVEL_NAMES[i], self.list_owned(i)) |
1697 | 5ae4945a | Iustin Pop | for i in self.__keyring.keys()]), )) |
1698 | 7ee7c0c7 | Guido Trotter | |
1699 | 7ee7c0c7 | Guido Trotter | # Release will complain if we don't own the locks already
|
1700 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level].release(names) |
1701 | 7ee7c0c7 | Guido Trotter | |
1702 | 7ee7c0c7 | Guido Trotter | def add(self, level, names, acquired=0, shared=0): |
1703 | 7ee7c0c7 | Guido Trotter | """Add locks at the specified level.
|
1704 | 7ee7c0c7 | Guido Trotter |
|
1705 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS_MOD
|
1706 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be added
|
1707 | ec44d893 | Guido Trotter | @type names: list of strings
|
1708 | c41eea6e | Iustin Pop | @param names: names of the locks to acquire
|
1709 | ec44d893 | Guido Trotter | @type acquired: integer (0/1) used as a boolean
|
1710 | c41eea6e | Iustin Pop | @param acquired: whether to acquire the newly added locks
|
1711 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1712 | c41eea6e | Iustin Pop | @param shared: whether the acquisition will be shared
|
1713 | c41eea6e | Iustin Pop |
|
1714 | 7ee7c0c7 | Guido Trotter | """
|
1715 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS_MOD, "Invalid or immutable level %s" % level |
1716 | 7ee7c0c7 | Guido Trotter | assert self._BGL_owned(), ("You must own the BGL before performing other" |
1717 | 5ae4945a | Iustin Pop | " operations")
|
1718 | 7ee7c0c7 | Guido Trotter | assert not self._upper_owned(level), ("Cannot add locks at a level" |
1719 | 5ae4945a | Iustin Pop | " while owning some at a greater one")
|
1720 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level].add(names, acquired=acquired, shared=shared) |
1721 | 7ee7c0c7 | Guido Trotter | |
1722 | 5e0a6daf | Michael Hanselmann | def remove(self, level, names): |
1723 | 7ee7c0c7 | Guido Trotter | """Remove locks from the specified level.
|
1724 | 7ee7c0c7 | Guido Trotter |
|
1725 | c41eea6e | Iustin Pop | You must either already own the locks you are trying to remove
|
1726 | c41eea6e | Iustin Pop | exclusively or not own any lock at an upper level.
|
1727 | 7ee7c0c7 | Guido Trotter |
|
1728 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS_MOD
|
1729 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be removed
|
1730 | ec44d893 | Guido Trotter | @type names: list of strings
|
1731 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be removed
|
1732 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1733 | 7ee7c0c7 | Guido Trotter |
|
1734 | 7ee7c0c7 | Guido Trotter | """
|
1735 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS_MOD, "Invalid or immutable level %s" % level |
1736 | 7ee7c0c7 | Guido Trotter | assert self._BGL_owned(), ("You must own the BGL before performing other" |
1737 | 5ae4945a | Iustin Pop | " operations")
|
1738 | f12eadb3 | Iustin Pop | # Check we either own the level or don't own anything from here
|
1739 | f12eadb3 | Iustin Pop | # up. LockSet.remove() will check the case in which we don't own
|
1740 | f12eadb3 | Iustin Pop | # all the needed resources, or we have a shared ownership.
|
1741 | ee2b99e3 | Michael Hanselmann | assert self.is_owned(level) or not self._upper_owned(level), ( |
1742 | 7ee7c0c7 | Guido Trotter | "Cannot remove locks at a level while not owning it or"
|
1743 | 7ee7c0c7 | Guido Trotter | " owning some at a greater one")
|
1744 | 5e0a6daf | Michael Hanselmann | return self.__keyring[level].remove(names) |
1745 | 19b9ba9a | Michael Hanselmann | |
1746 | 19b9ba9a | Michael Hanselmann | |
1747 | 44b4eddc | Michael Hanselmann | def _MonitorSortKey((item, idx, num)): |
1748 | e4e35357 | Michael Hanselmann | """Sorting key function.
|
1749 | e4e35357 | Michael Hanselmann |
|
1750 | 44b4eddc | Michael Hanselmann | Sort by name, registration order and then order of information. This provides
|
1751 | 44b4eddc | Michael Hanselmann | a stable sort order over different providers, even if they return the same
|
1752 | 44b4eddc | Michael Hanselmann | name.
|
1753 | e4e35357 | Michael Hanselmann |
|
1754 | e4e35357 | Michael Hanselmann | """
|
1755 | e4e35357 | Michael Hanselmann | (name, _, _, _) = item |
1756 | e4e35357 | Michael Hanselmann | |
1757 | 44b4eddc | Michael Hanselmann | return (utils.NiceSortKey(name), num, idx)
|
1758 | e4e35357 | Michael Hanselmann | |
1759 | e4e35357 | Michael Hanselmann | |
1760 | 19b9ba9a | Michael Hanselmann | class LockMonitor(object): |
1761 | 19b9ba9a | Michael Hanselmann | _LOCK_ATTR = "_lock"
|
1762 | 19b9ba9a | Michael Hanselmann | |
1763 | 19b9ba9a | Michael Hanselmann | def __init__(self): |
1764 | 19b9ba9a | Michael Hanselmann | """Initializes this class.
|
1765 | 19b9ba9a | Michael Hanselmann |
|
1766 | 19b9ba9a | Michael Hanselmann | """
|
1767 | 19b9ba9a | Michael Hanselmann | self._lock = SharedLock("LockMonitor") |
1768 | 19b9ba9a | Michael Hanselmann | |
1769 | e4e35357 | Michael Hanselmann | # Counter for stable sorting
|
1770 | e4e35357 | Michael Hanselmann | self._counter = itertools.count(0) |
1771 | e4e35357 | Michael Hanselmann | |
1772 | 19b9ba9a | Michael Hanselmann | # Tracked locks. Weak references are used to avoid issues with circular
|
1773 | 19b9ba9a | Michael Hanselmann | # references and deletion.
|
1774 | 19b9ba9a | Michael Hanselmann | self._locks = weakref.WeakKeyDictionary()
|
1775 | 19b9ba9a | Michael Hanselmann | |
1776 | 19b9ba9a | Michael Hanselmann | @ssynchronized(_LOCK_ATTR)
|
1777 | 44b4eddc | Michael Hanselmann | def RegisterLock(self, provider): |
1778 | 19b9ba9a | Michael Hanselmann | """Registers a new lock.
|
1779 | 19b9ba9a | Michael Hanselmann |
|
1780 | 44b4eddc | Michael Hanselmann | @param provider: Object with a callable method named C{GetLockInfo}, taking
|
1781 | 44b4eddc | Michael Hanselmann | a single C{set} containing the requested information items
|
1782 | 44b4eddc | Michael Hanselmann | @note: It would be nicer to only receive the function generating the
|
1783 | 44b4eddc | Michael Hanselmann | requested information but, as it turns out, weak references to bound
|
1784 | 44b4eddc | Michael Hanselmann | methods (e.g. C{self.GetLockInfo}) are tricky; there are several
|
1785 | 44b4eddc | Michael Hanselmann | workarounds, but none of the ones I found works properly in combination
|
1786 | 44b4eddc | Michael Hanselmann | with a standard C{WeakKeyDictionary}
|
1787 | 44b4eddc | Michael Hanselmann |
|
1788 | 19b9ba9a | Michael Hanselmann | """
|
1789 | 44b4eddc | Michael Hanselmann | assert provider not in self._locks, "Duplicate registration" |
1790 | e4e35357 | Michael Hanselmann | |
1791 | e4e35357 | Michael Hanselmann | # There used to be a check for duplicate names here. As it turned out, when
|
1792 | e4e35357 | Michael Hanselmann | # a lock is re-created with the same name in a very short timeframe, the
|
1793 | e4e35357 | Michael Hanselmann | # previous instance might not yet be removed from the weakref dictionary.
|
1794 | e4e35357 | Michael Hanselmann | # By keeping track of the order of incoming registrations, a stable sort
|
1795 | e4e35357 | Michael Hanselmann | # ordering can still be guaranteed.
|
1796 | e4e35357 | Michael Hanselmann | |
1797 | 44b4eddc | Michael Hanselmann | self._locks[provider] = self._counter.next() |
1798 | 19b9ba9a | Michael Hanselmann | |
1799 | 24d16f76 | Michael Hanselmann | def _GetLockInfo(self, requested): |
1800 | 44b4eddc | Michael Hanselmann | """Get information from all locks.
|
1801 | 19b9ba9a | Michael Hanselmann |
|
1802 | 19b9ba9a | Michael Hanselmann | """
|
1803 | 44b4eddc | Michael Hanselmann | # Must hold lock while getting consistent list of tracked items
|
1804 | 44b4eddc | Michael Hanselmann | self._lock.acquire(shared=1) |
1805 | 44b4eddc | Michael Hanselmann | try:
|
1806 | 44b4eddc | Michael Hanselmann | items = self._locks.items()
|
1807 | 44b4eddc | Michael Hanselmann | finally:
|
1808 | 44b4eddc | Michael Hanselmann | self._lock.release()
|
1809 | 44b4eddc | Michael Hanselmann | |
1810 | 44b4eddc | Michael Hanselmann | return [(info, idx, num)
|
1811 | 44b4eddc | Michael Hanselmann | for (provider, num) in items |
1812 | 44b4eddc | Michael Hanselmann | for (idx, info) in enumerate(provider.GetLockInfo(requested))] |
1813 | 19b9ba9a | Michael Hanselmann | |
1814 | 24d16f76 | Michael Hanselmann | def _Query(self, fields): |
1815 | 24d16f76 | Michael Hanselmann | """Queries information from all locks.
|
1816 | 19b9ba9a | Michael Hanselmann |
|
1817 | 24d16f76 | Michael Hanselmann | @type fields: list of strings
|
1818 | 24d16f76 | Michael Hanselmann | @param fields: List of fields to return
|
1819 | 24d16f76 | Michael Hanselmann |
|
1820 | 24d16f76 | Michael Hanselmann | """
|
1821 | 24d16f76 | Michael Hanselmann | qobj = query.Query(query.LOCK_FIELDS, fields) |
1822 | 24d16f76 | Michael Hanselmann | |
1823 | e4e35357 | Michael Hanselmann | # Get all data with internal lock held and then sort by name and incoming
|
1824 | e4e35357 | Michael Hanselmann | # order
|
1825 | e4e35357 | Michael Hanselmann | lockinfo = sorted(self._GetLockInfo(qobj.RequestedData()), |
1826 | e4e35357 | Michael Hanselmann | key=_MonitorSortKey) |
1827 | 24d16f76 | Michael Hanselmann | |
1828 | e4e35357 | Michael Hanselmann | # Extract lock information and build query data
|
1829 | eb62069e | Iustin Pop | return (qobj, query.LockQueryData(map(compat.fst, lockinfo))) |
1830 | 19b9ba9a | Michael Hanselmann | |
1831 | 24d16f76 | Michael Hanselmann | def QueryLocks(self, fields): |
1832 | 19b9ba9a | Michael Hanselmann | """Queries information from all locks.
|
1833 | 19b9ba9a | Michael Hanselmann |
|
1834 | 19b9ba9a | Michael Hanselmann | @type fields: list of strings
|
1835 | 19b9ba9a | Michael Hanselmann | @param fields: List of fields to return
|
1836 | 19b9ba9a | Michael Hanselmann |
|
1837 | 19b9ba9a | Michael Hanselmann | """
|
1838 | 24d16f76 | Michael Hanselmann | (qobj, ctx) = self._Query(fields)
|
1839 | 19b9ba9a | Michael Hanselmann | |
1840 | 24d16f76 | Michael Hanselmann | # Prepare query response
|
1841 | 24d16f76 | Michael Hanselmann | return query.GetQueryResponse(qobj, ctx) |