root / lib / locking.py @ 63b4bb1e
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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 | eb62069e | Iustin Pop | # Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 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 | 84e344d4 | Michael Hanselmann | |
37 | a95fd5d7 | Guido Trotter | from ganeti import errors |
38 | 7ee7c0c7 | Guido Trotter | from ganeti import utils |
39 | cea881e5 | Michael Hanselmann | from ganeti import compat |
40 | 24d16f76 | Michael Hanselmann | from ganeti import query |
41 | 162c1c1f | Guido Trotter | |
42 | 162c1c1f | Guido Trotter | |
43 | c31825f7 | Michael Hanselmann | _EXCLUSIVE_TEXT = "exclusive"
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44 | c31825f7 | Michael Hanselmann | _SHARED_TEXT = "shared"
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45 | 24d16f76 | Michael Hanselmann | _DELETED_TEXT = "deleted"
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46 | c31825f7 | Michael Hanselmann | |
47 | 887c7aa6 | Michael Hanselmann | _DEFAULT_PRIORITY = 0
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48 | 887c7aa6 | Michael Hanselmann | |
49 | c31825f7 | Michael Hanselmann | |
50 | dbb11e8b | Guido Trotter | def ssynchronized(mylock, shared=0): |
51 | 42a999d1 | Guido Trotter | """Shared Synchronization decorator.
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52 | 42a999d1 | Guido Trotter |
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53 | 42a999d1 | Guido Trotter | Calls the function holding the given lock, either in exclusive or shared
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54 | 42a999d1 | Guido Trotter | mode. It requires the passed lock to be a SharedLock (or support its
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55 | 42a999d1 | Guido Trotter | semantics).
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56 | 42a999d1 | Guido Trotter |
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57 | dbb11e8b | Guido Trotter | @type mylock: lockable object or string
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58 | dbb11e8b | Guido Trotter | @param mylock: lock to acquire or class member name of the lock to acquire
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59 | dbb11e8b | Guido Trotter |
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60 | 42a999d1 | Guido Trotter | """
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61 | 42a999d1 | Guido Trotter | def wrap(fn): |
62 | 42a999d1 | Guido Trotter | def sync_function(*args, **kwargs): |
63 | dbb11e8b | Guido Trotter | if isinstance(mylock, basestring): |
64 | dbb11e8b | Guido Trotter | assert args, "cannot ssynchronize on non-class method: self not found" |
65 | dbb11e8b | Guido Trotter | # args[0] is "self"
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66 | dbb11e8b | Guido Trotter | lock = getattr(args[0], mylock) |
67 | dbb11e8b | Guido Trotter | else:
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68 | dbb11e8b | Guido Trotter | lock = mylock |
69 | 42a999d1 | Guido Trotter | lock.acquire(shared=shared) |
70 | 42a999d1 | Guido Trotter | try:
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71 | 42a999d1 | Guido Trotter | return fn(*args, **kwargs)
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72 | 42a999d1 | Guido Trotter | finally:
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73 | 42a999d1 | Guido Trotter | lock.release() |
74 | 42a999d1 | Guido Trotter | return sync_function
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75 | 42a999d1 | Guido Trotter | return wrap
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76 | 42a999d1 | Guido Trotter | |
77 | 42a999d1 | Guido Trotter | |
78 | 34cb5617 | Guido Trotter | class _SingleNotifyPipeConditionWaiter(object): |
79 | 34cb5617 | Guido Trotter | """Helper class for SingleNotifyPipeCondition
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80 | d76167a5 | Michael Hanselmann |
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81 | d76167a5 | Michael Hanselmann | """
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82 | d76167a5 | Michael Hanselmann | __slots__ = [ |
83 | d76167a5 | Michael Hanselmann | "_fd",
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84 | d76167a5 | Michael Hanselmann | "_poller",
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85 | d76167a5 | Michael Hanselmann | ] |
86 | d76167a5 | Michael Hanselmann | |
87 | 34cb5617 | Guido Trotter | def __init__(self, poller, fd): |
88 | 34cb5617 | Guido Trotter | """Constructor for _SingleNotifyPipeConditionWaiter
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89 | d76167a5 | Michael Hanselmann |
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90 | d76167a5 | Michael Hanselmann | @type poller: select.poll
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91 | d76167a5 | Michael Hanselmann | @param poller: Poller object
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92 | d76167a5 | Michael Hanselmann | @type fd: int
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93 | d76167a5 | Michael Hanselmann | @param fd: File descriptor to wait for
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94 | d76167a5 | Michael Hanselmann |
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95 | d76167a5 | Michael Hanselmann | """
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96 | d76167a5 | Michael Hanselmann | object.__init__(self) |
97 | d76167a5 | Michael Hanselmann | self._poller = poller
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98 | d76167a5 | Michael Hanselmann | self._fd = fd
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99 | d76167a5 | Michael Hanselmann | |
100 | d76167a5 | Michael Hanselmann | def __call__(self, timeout): |
101 | d76167a5 | Michael Hanselmann | """Wait for something to happen on the pipe.
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102 | d76167a5 | Michael Hanselmann |
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103 | d76167a5 | Michael Hanselmann | @type timeout: float or None
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104 | d76167a5 | Michael Hanselmann | @param timeout: Timeout for waiting (can be None)
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105 | d76167a5 | Michael Hanselmann |
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106 | d76167a5 | Michael Hanselmann | """
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107 | 557838c1 | Renรฉ Nussbaumer | running_timeout = utils.RunningTimeout(timeout, True)
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108 | f4e673fb | Michael Hanselmann | |
109 | f4e673fb | Michael Hanselmann | while True: |
110 | f4e673fb | Michael Hanselmann | remaining_time = running_timeout.Remaining() |
111 | f4e673fb | Michael Hanselmann | |
112 | b44b0141 | Michael Hanselmann | if remaining_time is not None: |
113 | b44b0141 | Michael Hanselmann | if remaining_time < 0.0: |
114 | b44b0141 | Michael Hanselmann | break
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115 | d76167a5 | Michael Hanselmann | |
116 | 413b7472 | Michael Hanselmann | # Our calculation uses seconds, poll() wants milliseconds
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117 | b44b0141 | Michael Hanselmann | remaining_time *= 1000
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118 | d76167a5 | Michael Hanselmann | |
119 | d76167a5 | Michael Hanselmann | try:
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120 | d76167a5 | Michael Hanselmann | result = self._poller.poll(remaining_time)
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121 | d76167a5 | Michael Hanselmann | except EnvironmentError, err: |
122 | d76167a5 | Michael Hanselmann | if err.errno != errno.EINTR:
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123 | d76167a5 | Michael Hanselmann | raise
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124 | d76167a5 | Michael Hanselmann | result = None
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125 | d76167a5 | Michael Hanselmann | |
126 | d76167a5 | Michael Hanselmann | # Check whether we were notified
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127 | d76167a5 | Michael Hanselmann | if result and result[0][0] == self._fd: |
128 | d76167a5 | Michael Hanselmann | break
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129 | d76167a5 | Michael Hanselmann | |
130 | d76167a5 | Michael Hanselmann | |
131 | 2419060d | Guido Trotter | class _BaseCondition(object): |
132 | 2419060d | Guido Trotter | """Base class containing common code for conditions.
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133 | 2419060d | Guido Trotter |
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134 | 2419060d | Guido Trotter | Some of this code is taken from python's threading module.
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135 | 2419060d | Guido Trotter |
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136 | 2419060d | Guido Trotter | """
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137 | 2419060d | Guido Trotter | __slots__ = [ |
138 | 2419060d | Guido Trotter | "_lock",
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139 | 2419060d | Guido Trotter | "acquire",
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140 | 2419060d | Guido Trotter | "release",
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141 | 7f890059 | Guido Trotter | "_is_owned",
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142 | 7f890059 | Guido Trotter | "_acquire_restore",
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143 | 7f890059 | Guido Trotter | "_release_save",
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144 | 2419060d | Guido Trotter | ] |
145 | 2419060d | Guido Trotter | |
146 | 2419060d | Guido Trotter | def __init__(self, lock): |
147 | 2419060d | Guido Trotter | """Constructor for _BaseCondition.
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148 | 2419060d | Guido Trotter |
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149 | 69b99987 | Michael Hanselmann | @type lock: threading.Lock
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150 | 2419060d | Guido Trotter | @param lock: condition base lock
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151 | 2419060d | Guido Trotter |
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152 | 2419060d | Guido Trotter | """
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153 | 2419060d | Guido Trotter | object.__init__(self) |
154 | 2419060d | Guido Trotter | |
155 | 7f890059 | Guido Trotter | try:
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156 | 7f890059 | Guido Trotter | self._release_save = lock._release_save
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157 | 7f890059 | Guido Trotter | except AttributeError: |
158 | 7f890059 | Guido Trotter | self._release_save = self._base_release_save |
159 | 7f890059 | Guido Trotter | try:
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160 | 7f890059 | Guido Trotter | self._acquire_restore = lock._acquire_restore
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161 | 7f890059 | Guido Trotter | except AttributeError: |
162 | 7f890059 | Guido Trotter | self._acquire_restore = self._base_acquire_restore |
163 | 7f890059 | Guido Trotter | try:
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164 | ee2b99e3 | Michael Hanselmann | self._is_owned = lock.is_owned
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165 | 7f890059 | Guido Trotter | except AttributeError: |
166 | 7f890059 | Guido Trotter | self._is_owned = self._base_is_owned |
167 | 2419060d | Guido Trotter | |
168 | 2419060d | Guido Trotter | self._lock = lock
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169 | 2419060d | Guido Trotter | |
170 | 2419060d | Guido Trotter | # Export the lock's acquire() and release() methods
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171 | 2419060d | Guido Trotter | self.acquire = lock.acquire
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172 | 2419060d | Guido Trotter | self.release = lock.release
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173 | 2419060d | Guido Trotter | |
174 | 7f890059 | Guido Trotter | def _base_is_owned(self): |
175 | 2419060d | Guido Trotter | """Check whether lock is owned by current thread.
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176 | 2419060d | Guido Trotter |
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177 | 2419060d | Guido Trotter | """
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178 | 2419060d | Guido Trotter | if self._lock.acquire(0): |
179 | 2419060d | Guido Trotter | self._lock.release()
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180 | 2419060d | Guido Trotter | return False |
181 | 2419060d | Guido Trotter | return True |
182 | 2419060d | Guido Trotter | |
183 | 7f890059 | Guido Trotter | def _base_release_save(self): |
184 | 7f890059 | Guido Trotter | self._lock.release()
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185 | 7f890059 | Guido Trotter | |
186 | 7f890059 | Guido Trotter | def _base_acquire_restore(self, _): |
187 | 7f890059 | Guido Trotter | self._lock.acquire()
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188 | 7f890059 | Guido Trotter | |
189 | 2419060d | Guido Trotter | def _check_owned(self): |
190 | 2419060d | Guido Trotter | """Raise an exception if the current thread doesn't own the lock.
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191 | 2419060d | Guido Trotter |
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192 | 2419060d | Guido Trotter | """
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193 | 2419060d | Guido Trotter | if not self._is_owned(): |
194 | 2419060d | Guido Trotter | raise RuntimeError("cannot work with un-aquired lock") |
195 | 2419060d | Guido Trotter | |
196 | 2419060d | Guido Trotter | |
197 | 34cb5617 | Guido Trotter | class SingleNotifyPipeCondition(_BaseCondition): |
198 | 34cb5617 | Guido Trotter | """Condition which can only be notified once.
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199 | d76167a5 | Michael Hanselmann |
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200 | 34cb5617 | Guido Trotter | This condition class uses pipes and poll, internally, to be able to wait for
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201 | 34cb5617 | Guido Trotter | notification with a timeout, without resorting to polling. It is almost
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202 | 34cb5617 | Guido Trotter | compatible with Python's threading.Condition, with the following differences:
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203 | 34cb5617 | Guido Trotter | - notifyAll can only be called once, and no wait can happen after that
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204 | 34cb5617 | Guido Trotter | - notify is not supported, only notifyAll
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205 | d76167a5 | Michael Hanselmann |
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206 | d76167a5 | Michael Hanselmann | """
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207 | 34cb5617 | Guido Trotter | |
208 | 154b9580 | Balazs Lecz | __slots__ = [ |
209 | d76167a5 | Michael Hanselmann | "_poller",
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210 | d76167a5 | Michael Hanselmann | "_read_fd",
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211 | d76167a5 | Michael Hanselmann | "_write_fd",
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212 | d76167a5 | Michael Hanselmann | "_nwaiters",
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213 | 34cb5617 | Guido Trotter | "_notified",
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214 | d76167a5 | Michael Hanselmann | ] |
215 | d76167a5 | Michael Hanselmann | |
216 | 34cb5617 | Guido Trotter | _waiter_class = _SingleNotifyPipeConditionWaiter |
217 | d76167a5 | Michael Hanselmann | |
218 | 34cb5617 | Guido Trotter | def __init__(self, lock): |
219 | 34cb5617 | Guido Trotter | """Constructor for SingleNotifyPipeCondition
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220 | d76167a5 | Michael Hanselmann |
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221 | d76167a5 | Michael Hanselmann | """
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222 | 34cb5617 | Guido Trotter | _BaseCondition.__init__(self, lock)
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223 | d76167a5 | Michael Hanselmann | self._nwaiters = 0 |
224 | 34cb5617 | Guido Trotter | self._notified = False |
225 | 34cb5617 | Guido Trotter | self._read_fd = None |
226 | 34cb5617 | Guido Trotter | self._write_fd = None |
227 | 34cb5617 | Guido Trotter | self._poller = None |
228 | d76167a5 | Michael Hanselmann | |
229 | 34cb5617 | Guido Trotter | def _check_unnotified(self): |
230 | 69b99987 | Michael Hanselmann | """Throws an exception if already notified.
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231 | 69b99987 | Michael Hanselmann |
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232 | 69b99987 | Michael Hanselmann | """
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233 | 34cb5617 | Guido Trotter | if self._notified: |
234 | 34cb5617 | Guido Trotter | raise RuntimeError("cannot use already notified condition") |
235 | d76167a5 | Michael Hanselmann | |
236 | 34cb5617 | Guido Trotter | def _Cleanup(self): |
237 | 34cb5617 | Guido Trotter | """Cleanup open file descriptors, if any.
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238 | d76167a5 | Michael Hanselmann |
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239 | d76167a5 | Michael Hanselmann | """
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240 | 34cb5617 | Guido Trotter | if self._read_fd is not None: |
241 | 34cb5617 | Guido Trotter | os.close(self._read_fd)
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242 | 34cb5617 | Guido Trotter | self._read_fd = None |
243 | d76167a5 | Michael Hanselmann | |
244 | 34cb5617 | Guido Trotter | if self._write_fd is not None: |
245 | 34cb5617 | Guido Trotter | os.close(self._write_fd)
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246 | 34cb5617 | Guido Trotter | self._write_fd = None |
247 | 34cb5617 | Guido Trotter | self._poller = None |
248 | d76167a5 | Michael Hanselmann | |
249 | 83f2d5f6 | Michael Hanselmann | def wait(self, timeout): |
250 | 34cb5617 | Guido Trotter | """Wait for a notification.
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251 | d76167a5 | Michael Hanselmann |
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252 | 34cb5617 | Guido Trotter | @type timeout: float or None
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253 | 34cb5617 | Guido Trotter | @param timeout: Waiting timeout (can be None)
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254 | d76167a5 | Michael Hanselmann |
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255 | d76167a5 | Michael Hanselmann | """
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256 | 34cb5617 | Guido Trotter | self._check_owned()
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257 | 34cb5617 | Guido Trotter | self._check_unnotified()
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258 | d76167a5 | Michael Hanselmann | |
259 | 34cb5617 | Guido Trotter | self._nwaiters += 1 |
260 | 34cb5617 | Guido Trotter | try:
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261 | 34cb5617 | Guido Trotter | if self._poller is None: |
262 | 34cb5617 | Guido Trotter | (self._read_fd, self._write_fd) = os.pipe() |
263 | 34cb5617 | Guido Trotter | self._poller = select.poll()
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264 | 34cb5617 | Guido Trotter | self._poller.register(self._read_fd, select.POLLHUP) |
265 | d76167a5 | Michael Hanselmann | |
266 | 34cb5617 | Guido Trotter | wait_fn = self._waiter_class(self._poller, self._read_fd) |
267 | 7f890059 | Guido Trotter | state = self._release_save()
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268 | 34cb5617 | Guido Trotter | try:
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269 | 34cb5617 | Guido Trotter | # Wait for notification
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270 | 34cb5617 | Guido Trotter | wait_fn(timeout) |
271 | 34cb5617 | Guido Trotter | finally:
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272 | 34cb5617 | Guido Trotter | # Re-acquire lock
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273 | 7f890059 | Guido Trotter | self._acquire_restore(state)
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274 | 34cb5617 | Guido Trotter | finally:
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275 | 34cb5617 | Guido Trotter | self._nwaiters -= 1 |
276 | 34cb5617 | Guido Trotter | if self._nwaiters == 0: |
277 | 34cb5617 | Guido Trotter | self._Cleanup()
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278 | d76167a5 | Michael Hanselmann | |
279 | b459a848 | Andrea Spadaccini | def notifyAll(self): # pylint: disable=C0103 |
280 | d76167a5 | Michael Hanselmann | """Close the writing side of the pipe to notify all waiters.
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281 | d76167a5 | Michael Hanselmann |
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282 | d76167a5 | Michael Hanselmann | """
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283 | 34cb5617 | Guido Trotter | self._check_owned()
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284 | 34cb5617 | Guido Trotter | self._check_unnotified()
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285 | 34cb5617 | Guido Trotter | self._notified = True |
286 | d76167a5 | Michael Hanselmann | if self._write_fd is not None: |
287 | d76167a5 | Michael Hanselmann | os.close(self._write_fd)
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288 | d76167a5 | Michael Hanselmann | self._write_fd = None |
289 | d76167a5 | Michael Hanselmann | |
290 | d76167a5 | Michael Hanselmann | |
291 | 34cb5617 | Guido Trotter | class PipeCondition(_BaseCondition): |
292 | 48dabc6a | Michael Hanselmann | """Group-only non-polling condition with counters.
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293 | 48dabc6a | Michael Hanselmann |
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294 | 48dabc6a | Michael Hanselmann | This condition class uses pipes and poll, internally, to be able to wait for
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295 | 48dabc6a | Michael Hanselmann | notification with a timeout, without resorting to polling. It is almost
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296 | 48dabc6a | Michael Hanselmann | compatible with Python's threading.Condition, but only supports notifyAll and
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297 | 48dabc6a | Michael Hanselmann | non-recursive locks. As an additional features it's able to report whether
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298 | 48dabc6a | Michael Hanselmann | there are any waiting threads.
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299 | 48dabc6a | Michael Hanselmann |
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300 | 48dabc6a | Michael Hanselmann | """
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301 | 154b9580 | Balazs Lecz | __slots__ = [ |
302 | c31825f7 | Michael Hanselmann | "_waiters",
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303 | 34cb5617 | Guido Trotter | "_single_condition",
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304 | 48dabc6a | Michael Hanselmann | ] |
305 | 48dabc6a | Michael Hanselmann | |
306 | 34cb5617 | Guido Trotter | _single_condition_class = SingleNotifyPipeCondition |
307 | 48dabc6a | Michael Hanselmann | |
308 | 48dabc6a | Michael Hanselmann | def __init__(self, lock): |
309 | 48dabc6a | Michael Hanselmann | """Initializes this class.
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310 | 48dabc6a | Michael Hanselmann |
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311 | 48dabc6a | Michael Hanselmann | """
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312 | 2419060d | Guido Trotter | _BaseCondition.__init__(self, lock)
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313 | c31825f7 | Michael Hanselmann | self._waiters = set() |
314 | 34cb5617 | Guido Trotter | self._single_condition = self._single_condition_class(self._lock) |
315 | 48dabc6a | Michael Hanselmann | |
316 | 83f2d5f6 | Michael Hanselmann | def wait(self, timeout): |
317 | 48dabc6a | Michael Hanselmann | """Wait for a notification.
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318 | 48dabc6a | Michael Hanselmann |
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319 | 48dabc6a | Michael Hanselmann | @type timeout: float or None
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320 | 48dabc6a | Michael Hanselmann | @param timeout: Waiting timeout (can be None)
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321 | 48dabc6a | Michael Hanselmann |
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322 | 48dabc6a | Michael Hanselmann | """
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323 | 48dabc6a | Michael Hanselmann | self._check_owned()
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324 | 48dabc6a | Michael Hanselmann | |
325 | 48dabc6a | Michael Hanselmann | # Keep local reference to the pipe. It could be replaced by another thread
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326 | 48dabc6a | Michael Hanselmann | # notifying while we're waiting.
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327 | c31825f7 | Michael Hanselmann | cond = self._single_condition
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328 | 48dabc6a | Michael Hanselmann | |
329 | c31825f7 | Michael Hanselmann | self._waiters.add(threading.currentThread())
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330 | 48dabc6a | Michael Hanselmann | try:
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331 | c31825f7 | Michael Hanselmann | cond.wait(timeout) |
332 | 48dabc6a | Michael Hanselmann | finally:
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333 | c31825f7 | Michael Hanselmann | self._check_owned()
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334 | c31825f7 | Michael Hanselmann | self._waiters.remove(threading.currentThread())
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335 | 48dabc6a | Michael Hanselmann | |
336 | b459a848 | Andrea Spadaccini | def notifyAll(self): # pylint: disable=C0103 |
337 | 48dabc6a | Michael Hanselmann | """Notify all currently waiting threads.
|
338 | 48dabc6a | Michael Hanselmann |
|
339 | 48dabc6a | Michael Hanselmann | """
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340 | 48dabc6a | Michael Hanselmann | self._check_owned()
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341 | 34cb5617 | Guido Trotter | self._single_condition.notifyAll()
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342 | 34cb5617 | Guido Trotter | self._single_condition = self._single_condition_class(self._lock) |
343 | 48dabc6a | Michael Hanselmann | |
344 | c31825f7 | Michael Hanselmann | def get_waiting(self): |
345 | c31825f7 | Michael Hanselmann | """Returns a list of all waiting threads.
|
346 | c31825f7 | Michael Hanselmann |
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347 | c31825f7 | Michael Hanselmann | """
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348 | c31825f7 | Michael Hanselmann | self._check_owned()
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349 | c31825f7 | Michael Hanselmann | |
350 | c31825f7 | Michael Hanselmann | return self._waiters |
351 | c31825f7 | Michael Hanselmann | |
352 | 48dabc6a | Michael Hanselmann | def has_waiting(self): |
353 | 48dabc6a | Michael Hanselmann | """Returns whether there are active waiters.
|
354 | 48dabc6a | Michael Hanselmann |
|
355 | 48dabc6a | Michael Hanselmann | """
|
356 | 48dabc6a | Michael Hanselmann | self._check_owned()
|
357 | 48dabc6a | Michael Hanselmann | |
358 | c31825f7 | Michael Hanselmann | return bool(self._waiters) |
359 | 48dabc6a | Michael Hanselmann | |
360 | 20699809 | Michael Hanselmann | def __repr__(self): |
361 | 20699809 | Michael Hanselmann | return ("<%s.%s waiters=%s at %#x>" % |
362 | 20699809 | Michael Hanselmann | (self.__class__.__module__, self.__class__.__name__, |
363 | 20699809 | Michael Hanselmann | self._waiters, id(self))) |
364 | 20699809 | Michael Hanselmann | |
365 | 48dabc6a | Michael Hanselmann | |
366 | 887c7aa6 | Michael Hanselmann | class _PipeConditionWithMode(PipeCondition): |
367 | 887c7aa6 | Michael Hanselmann | __slots__ = [ |
368 | 887c7aa6 | Michael Hanselmann | "shared",
|
369 | 887c7aa6 | Michael Hanselmann | ] |
370 | 887c7aa6 | Michael Hanselmann | |
371 | 887c7aa6 | Michael Hanselmann | def __init__(self, lock, shared): |
372 | 887c7aa6 | Michael Hanselmann | """Initializes this class.
|
373 | 887c7aa6 | Michael Hanselmann |
|
374 | 887c7aa6 | Michael Hanselmann | """
|
375 | 887c7aa6 | Michael Hanselmann | self.shared = shared
|
376 | 887c7aa6 | Michael Hanselmann | PipeCondition.__init__(self, lock)
|
377 | 887c7aa6 | Michael Hanselmann | |
378 | 887c7aa6 | Michael Hanselmann | |
379 | 84e344d4 | Michael Hanselmann | class SharedLock(object): |
380 | 162c1c1f | Guido Trotter | """Implements a shared lock.
|
381 | 162c1c1f | Guido Trotter |
|
382 | 05ad571c | Michael Hanselmann | Multiple threads can acquire the lock in a shared way by calling
|
383 | 05ad571c | Michael Hanselmann | C{acquire(shared=1)}. In order to acquire the lock in an exclusive way
|
384 | 05ad571c | Michael Hanselmann | threads can call C{acquire(shared=0)}.
|
385 | 162c1c1f | Guido Trotter |
|
386 | 887c7aa6 | Michael Hanselmann | Notes on data structures: C{__pending} contains a priority queue (heapq) of
|
387 | 887c7aa6 | Michael Hanselmann | all pending acquires: C{[(priority1: prioqueue1), (priority2: prioqueue2),
|
388 | 887c7aa6 | Michael Hanselmann | ...]}. Each per-priority queue contains a normal in-order list of conditions
|
389 | 887c7aa6 | Michael Hanselmann | to be notified when the lock can be acquired. Shared locks are grouped
|
390 | 887c7aa6 | Michael Hanselmann | together by priority and the condition for them is stored in
|
391 | 887c7aa6 | Michael Hanselmann | C{__pending_shared} if it already exists. C{__pending_by_prio} keeps
|
392 | 887c7aa6 | Michael Hanselmann | references for the per-priority queues indexed by priority for faster access.
|
393 | 162c1c1f | Guido Trotter |
|
394 | 7f93570a | Iustin Pop | @type name: string
|
395 | 7f93570a | Iustin Pop | @ivar name: the name of the lock
|
396 | 7f93570a | Iustin Pop |
|
397 | 162c1c1f | Guido Trotter | """
|
398 | 84e344d4 | Michael Hanselmann | __slots__ = [ |
399 | 19b9ba9a | Michael Hanselmann | "__weakref__",
|
400 | 84e344d4 | Michael Hanselmann | "__deleted",
|
401 | 84e344d4 | Michael Hanselmann | "__exc",
|
402 | 84e344d4 | Michael Hanselmann | "__lock",
|
403 | 84e344d4 | Michael Hanselmann | "__pending",
|
404 | 887c7aa6 | Michael Hanselmann | "__pending_by_prio",
|
405 | 887c7aa6 | Michael Hanselmann | "__pending_shared",
|
406 | 84e344d4 | Michael Hanselmann | "__shr",
|
407 | 7f93570a | Iustin Pop | "name",
|
408 | 84e344d4 | Michael Hanselmann | ] |
409 | 84e344d4 | Michael Hanselmann | |
410 | 887c7aa6 | Michael Hanselmann | __condition_class = _PipeConditionWithMode |
411 | 84e344d4 | Michael Hanselmann | |
412 | 19b9ba9a | Michael Hanselmann | def __init__(self, name, monitor=None): |
413 | 84e344d4 | Michael Hanselmann | """Construct a new SharedLock.
|
414 | 84e344d4 | Michael Hanselmann |
|
415 | 7f93570a | Iustin Pop | @param name: the name of the lock
|
416 | 19b9ba9a | Michael Hanselmann | @type monitor: L{LockMonitor}
|
417 | 19b9ba9a | Michael Hanselmann | @param monitor: Lock monitor with which to register
|
418 | 7f93570a | Iustin Pop |
|
419 | 84e344d4 | Michael Hanselmann | """
|
420 | 84e344d4 | Michael Hanselmann | object.__init__(self) |
421 | 84e344d4 | Michael Hanselmann | |
422 | 7f93570a | Iustin Pop | self.name = name
|
423 | 7f93570a | Iustin Pop | |
424 | 84e344d4 | Michael Hanselmann | # Internal lock
|
425 | 162c1c1f | Guido Trotter | self.__lock = threading.Lock()
|
426 | 162c1c1f | Guido Trotter | |
427 | 84e344d4 | Michael Hanselmann | # Queue containing waiting acquires
|
428 | 84e344d4 | Michael Hanselmann | self.__pending = []
|
429 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio = {}
|
430 | 887c7aa6 | Michael Hanselmann | self.__pending_shared = {}
|
431 | 84e344d4 | Michael Hanselmann | |
432 | 84e344d4 | Michael Hanselmann | # Current lock holders
|
433 | 162c1c1f | Guido Trotter | self.__shr = set() |
434 | 162c1c1f | Guido Trotter | self.__exc = None |
435 | 162c1c1f | Guido Trotter | |
436 | a95fd5d7 | Guido Trotter | # is this lock in the deleted state?
|
437 | a95fd5d7 | Guido Trotter | self.__deleted = False |
438 | a95fd5d7 | Guido Trotter | |
439 | 19b9ba9a | Michael Hanselmann | # Register with lock monitor
|
440 | 19b9ba9a | Michael Hanselmann | if monitor:
|
441 | 44b4eddc | Michael Hanselmann | logging.debug("Adding lock %s to monitor", name)
|
442 | 19b9ba9a | Michael Hanselmann | monitor.RegisterLock(self)
|
443 | 19b9ba9a | Michael Hanselmann | |
444 | 20699809 | Michael Hanselmann | def __repr__(self): |
445 | 20699809 | Michael Hanselmann | return ("<%s.%s name=%s at %#x>" % |
446 | 20699809 | Michael Hanselmann | (self.__class__.__module__, self.__class__.__name__, |
447 | 20699809 | Michael Hanselmann | self.name, id(self))) |
448 | 20699809 | Michael Hanselmann | |
449 | 44b4eddc | Michael Hanselmann | def GetLockInfo(self, requested): |
450 | 19b9ba9a | Michael Hanselmann | """Retrieves information for querying locks.
|
451 | 19b9ba9a | Michael Hanselmann |
|
452 | 24d16f76 | Michael Hanselmann | @type requested: set
|
453 | 24d16f76 | Michael Hanselmann | @param requested: Requested information, see C{query.LQ_*}
|
454 | 19b9ba9a | Michael Hanselmann |
|
455 | 19b9ba9a | Michael Hanselmann | """
|
456 | 19b9ba9a | Michael Hanselmann | self.__lock.acquire()
|
457 | 19b9ba9a | Michael Hanselmann | try:
|
458 | 19b9ba9a | Michael Hanselmann | # Note: to avoid unintentional race conditions, no references to
|
459 | 19b9ba9a | Michael Hanselmann | # modifiable objects should be returned unless they were created in this
|
460 | 19b9ba9a | Michael Hanselmann | # function.
|
461 | 24d16f76 | Michael Hanselmann | mode = None
|
462 | 24d16f76 | Michael Hanselmann | owner_names = None
|
463 | 24d16f76 | Michael Hanselmann | |
464 | 24d16f76 | Michael Hanselmann | if query.LQ_MODE in requested: |
465 | 24d16f76 | Michael Hanselmann | if self.__deleted: |
466 | 24d16f76 | Michael Hanselmann | mode = _DELETED_TEXT |
467 | 24d16f76 | Michael Hanselmann | assert not (self.__exc or self.__shr) |
468 | 24d16f76 | Michael Hanselmann | elif self.__exc: |
469 | 24d16f76 | Michael Hanselmann | mode = _EXCLUSIVE_TEXT |
470 | 24d16f76 | Michael Hanselmann | elif self.__shr: |
471 | 24d16f76 | Michael Hanselmann | mode = _SHARED_TEXT |
472 | 24d16f76 | Michael Hanselmann | |
473 | 24d16f76 | Michael Hanselmann | # Current owner(s) are wanted
|
474 | 24d16f76 | Michael Hanselmann | if query.LQ_OWNER in requested: |
475 | 24d16f76 | Michael Hanselmann | if self.__exc: |
476 | 24d16f76 | Michael Hanselmann | owner = [self.__exc]
|
477 | 19b9ba9a | Michael Hanselmann | else:
|
478 | 24d16f76 | Michael Hanselmann | owner = self.__shr
|
479 | 24d16f76 | Michael Hanselmann | |
480 | 24d16f76 | Michael Hanselmann | if owner:
|
481 | 24d16f76 | Michael Hanselmann | assert not self.__deleted |
482 | 24d16f76 | Michael Hanselmann | owner_names = [i.getName() for i in owner] |
483 | 19b9ba9a | Michael Hanselmann | |
484 | 24d16f76 | Michael Hanselmann | # Pending acquires are wanted
|
485 | 24d16f76 | Michael Hanselmann | if query.LQ_PENDING in requested: |
486 | 24d16f76 | Michael Hanselmann | pending = [] |
487 | 24d16f76 | Michael Hanselmann | |
488 | 24d16f76 | Michael Hanselmann | # Sorting instead of copying and using heaq functions for simplicity
|
489 | 24d16f76 | Michael Hanselmann | for (_, prioqueue) in sorted(self.__pending): |
490 | 24d16f76 | Michael Hanselmann | for cond in prioqueue: |
491 | 24d16f76 | Michael Hanselmann | if cond.shared:
|
492 | 24d16f76 | Michael Hanselmann | pendmode = _SHARED_TEXT |
493 | 24d16f76 | Michael Hanselmann | else:
|
494 | 24d16f76 | Michael Hanselmann | pendmode = _EXCLUSIVE_TEXT |
495 | 24d16f76 | Michael Hanselmann | |
496 | 24d16f76 | Michael Hanselmann | # List of names will be sorted in L{query._GetLockPending}
|
497 | 24d16f76 | Michael Hanselmann | pending.append((pendmode, [i.getName() |
498 | 24d16f76 | Michael Hanselmann | for i in cond.get_waiting()])) |
499 | 24d16f76 | Michael Hanselmann | else:
|
500 | 24d16f76 | Michael Hanselmann | pending = None
|
501 | 24d16f76 | Michael Hanselmann | |
502 | 44b4eddc | Michael Hanselmann | return [(self.name, mode, owner_names, pending)] |
503 | 19b9ba9a | Michael Hanselmann | finally:
|
504 | 19b9ba9a | Michael Hanselmann | self.__lock.release()
|
505 | 19b9ba9a | Michael Hanselmann | |
506 | 84e344d4 | Michael Hanselmann | def __check_deleted(self): |
507 | 84e344d4 | Michael Hanselmann | """Raises an exception if the lock has been deleted.
|
508 | 84e344d4 | Michael Hanselmann |
|
509 | 84e344d4 | Michael Hanselmann | """
|
510 | 84e344d4 | Michael Hanselmann | if self.__deleted: |
511 | 7f93570a | Iustin Pop | raise errors.LockError("Deleted lock %s" % self.name) |
512 | 84e344d4 | Michael Hanselmann | |
513 | 162c1c1f | Guido Trotter | def __is_sharer(self): |
514 | 84e344d4 | Michael Hanselmann | """Is the current thread sharing the lock at this time?
|
515 | 84e344d4 | Michael Hanselmann |
|
516 | 84e344d4 | Michael Hanselmann | """
|
517 | 162c1c1f | Guido Trotter | return threading.currentThread() in self.__shr |
518 | 162c1c1f | Guido Trotter | |
519 | 162c1c1f | Guido Trotter | def __is_exclusive(self): |
520 | 84e344d4 | Michael Hanselmann | """Is the current thread holding the lock exclusively at this time?
|
521 | 84e344d4 | Michael Hanselmann |
|
522 | 84e344d4 | Michael Hanselmann | """
|
523 | 162c1c1f | Guido Trotter | return threading.currentThread() == self.__exc |
524 | 162c1c1f | Guido Trotter | |
525 | 162c1c1f | Guido Trotter | def __is_owned(self, shared=-1): |
526 | 162c1c1f | Guido Trotter | """Is the current thread somehow owning the lock at this time?
|
527 | 162c1c1f | Guido Trotter |
|
528 | 162c1c1f | Guido Trotter | This is a private version of the function, which presumes you're holding
|
529 | 162c1c1f | Guido Trotter | the internal lock.
|
530 | 162c1c1f | Guido Trotter |
|
531 | 162c1c1f | Guido Trotter | """
|
532 | 162c1c1f | Guido Trotter | if shared < 0: |
533 | 162c1c1f | Guido Trotter | return self.__is_sharer() or self.__is_exclusive() |
534 | 162c1c1f | Guido Trotter | elif shared:
|
535 | 162c1c1f | Guido Trotter | return self.__is_sharer() |
536 | 162c1c1f | Guido Trotter | else:
|
537 | 162c1c1f | Guido Trotter | return self.__is_exclusive() |
538 | 162c1c1f | Guido Trotter | |
539 | ee2b99e3 | Michael Hanselmann | def is_owned(self, shared=-1): |
540 | 162c1c1f | Guido Trotter | """Is the current thread somehow owning the lock at this time?
|
541 | 162c1c1f | Guido Trotter |
|
542 | c41eea6e | Iustin Pop | @param shared:
|
543 | c41eea6e | Iustin Pop | - < 0: check for any type of ownership (default)
|
544 | c41eea6e | Iustin Pop | - 0: check for exclusive ownership
|
545 | c41eea6e | Iustin Pop | - > 0: check for shared ownership
|
546 | 162c1c1f | Guido Trotter |
|
547 | 162c1c1f | Guido Trotter | """
|
548 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
549 | 162c1c1f | Guido Trotter | try:
|
550 | 84e344d4 | Michael Hanselmann | return self.__is_owned(shared=shared) |
551 | 162c1c1f | Guido Trotter | finally:
|
552 | 162c1c1f | Guido Trotter | self.__lock.release()
|
553 | 162c1c1f | Guido Trotter | |
554 | ee2b99e3 | Michael Hanselmann | #: Necessary to remain compatible with threading.Condition, which tries to
|
555 | ee2b99e3 | Michael Hanselmann | #: retrieve a locks' "_is_owned" attribute
|
556 | ee2b99e3 | Michael Hanselmann | _is_owned = is_owned |
557 | fdfe88b1 | Michael Hanselmann | |
558 | 84e344d4 | Michael Hanselmann | def _count_pending(self): |
559 | 84e344d4 | Michael Hanselmann | """Returns the number of pending acquires.
|
560 | a95fd5d7 | Guido Trotter |
|
561 | 84e344d4 | Michael Hanselmann | @rtype: int
|
562 | a95fd5d7 | Guido Trotter |
|
563 | a95fd5d7 | Guido Trotter | """
|
564 | 84e344d4 | Michael Hanselmann | self.__lock.acquire()
|
565 | 84e344d4 | Michael Hanselmann | try:
|
566 | 887c7aa6 | Michael Hanselmann | return sum(len(prioqueue) for (_, prioqueue) in self.__pending) |
567 | 887c7aa6 | Michael Hanselmann | finally:
|
568 | 887c7aa6 | Michael Hanselmann | self.__lock.release()
|
569 | 887c7aa6 | Michael Hanselmann | |
570 | 887c7aa6 | Michael Hanselmann | def _check_empty(self): |
571 | 887c7aa6 | Michael Hanselmann | """Checks whether there are any pending acquires.
|
572 | 887c7aa6 | Michael Hanselmann |
|
573 | 887c7aa6 | Michael Hanselmann | @rtype: bool
|
574 | 887c7aa6 | Michael Hanselmann |
|
575 | 887c7aa6 | Michael Hanselmann | """
|
576 | 887c7aa6 | Michael Hanselmann | self.__lock.acquire()
|
577 | 887c7aa6 | Michael Hanselmann | try:
|
578 | 887c7aa6 | Michael Hanselmann | # Order is important: __find_first_pending_queue modifies __pending
|
579 | 113359fe | Michael Hanselmann | (_, prioqueue) = self.__find_first_pending_queue()
|
580 | 113359fe | Michael Hanselmann | |
581 | 113359fe | Michael Hanselmann | return not (prioqueue or |
582 | 887c7aa6 | Michael Hanselmann | self.__pending or |
583 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio or |
584 | 887c7aa6 | Michael Hanselmann | self.__pending_shared)
|
585 | 84e344d4 | Michael Hanselmann | finally:
|
586 | 84e344d4 | Michael Hanselmann | self.__lock.release()
|
587 | a95fd5d7 | Guido Trotter | |
588 | 84e344d4 | Michael Hanselmann | def __do_acquire(self, shared): |
589 | 84e344d4 | Michael Hanselmann | """Actually acquire the lock.
|
590 | 84e344d4 | Michael Hanselmann |
|
591 | 84e344d4 | Michael Hanselmann | """
|
592 | 84e344d4 | Michael Hanselmann | if shared:
|
593 | 84e344d4 | Michael Hanselmann | self.__shr.add(threading.currentThread())
|
594 | 84e344d4 | Michael Hanselmann | else:
|
595 | 84e344d4 | Michael Hanselmann | self.__exc = threading.currentThread()
|
596 | a95fd5d7 | Guido Trotter | |
597 | 84e344d4 | Michael Hanselmann | def __can_acquire(self, shared): |
598 | 84e344d4 | Michael Hanselmann | """Determine whether lock can be acquired.
|
599 | a95fd5d7 | Guido Trotter |
|
600 | a95fd5d7 | Guido Trotter | """
|
601 | 84e344d4 | Michael Hanselmann | if shared:
|
602 | 84e344d4 | Michael Hanselmann | return self.__exc is None |
603 | 84e344d4 | Michael Hanselmann | else:
|
604 | 84e344d4 | Michael Hanselmann | return len(self.__shr) == 0 and self.__exc is None |
605 | a95fd5d7 | Guido Trotter | |
606 | 887c7aa6 | Michael Hanselmann | def __find_first_pending_queue(self): |
607 | 887c7aa6 | Michael Hanselmann | """Tries to find the topmost queued entry with pending acquires.
|
608 | 887c7aa6 | Michael Hanselmann |
|
609 | 887c7aa6 | Michael Hanselmann | Removes empty entries while going through the list.
|
610 | 887c7aa6 | Michael Hanselmann |
|
611 | 887c7aa6 | Michael Hanselmann | """
|
612 | 887c7aa6 | Michael Hanselmann | while self.__pending: |
613 | 887c7aa6 | Michael Hanselmann | (priority, prioqueue) = self.__pending[0] |
614 | 887c7aa6 | Michael Hanselmann | |
615 | 887c7aa6 | Michael Hanselmann | if prioqueue:
|
616 | 113359fe | Michael Hanselmann | return (priority, prioqueue)
|
617 | 887c7aa6 | Michael Hanselmann | |
618 | 113359fe | Michael Hanselmann | # Remove empty queue
|
619 | 113359fe | Michael Hanselmann | heapq.heappop(self.__pending)
|
620 | 113359fe | Michael Hanselmann | del self.__pending_by_prio[priority] |
621 | 113359fe | Michael Hanselmann | assert priority not in self.__pending_shared |
622 | 113359fe | Michael Hanselmann | |
623 | 113359fe | Michael Hanselmann | return (None, None) |
624 | 887c7aa6 | Michael Hanselmann | |
625 | 84e344d4 | Michael Hanselmann | def __is_on_top(self, cond): |
626 | 84e344d4 | Michael Hanselmann | """Checks whether the passed condition is on top of the queue.
|
627 | a95fd5d7 | Guido Trotter |
|
628 | 84e344d4 | Michael Hanselmann | The caller must make sure the queue isn't empty.
|
629 | a95fd5d7 | Guido Trotter |
|
630 | 84e344d4 | Michael Hanselmann | """
|
631 | 113359fe | Michael Hanselmann | (_, prioqueue) = self.__find_first_pending_queue()
|
632 | 113359fe | Michael Hanselmann | |
633 | 113359fe | Michael Hanselmann | return cond == prioqueue[0] |
634 | 4d686df8 | Guido Trotter | |
635 | 887c7aa6 | Michael Hanselmann | def __acquire_unlocked(self, shared, timeout, priority): |
636 | 84e344d4 | Michael Hanselmann | """Acquire a shared lock.
|
637 | 9216a9f7 | Michael Hanselmann |
|
638 | 84e344d4 | Michael Hanselmann | @param shared: whether to acquire in shared mode; by default an
|
639 | 84e344d4 | Michael Hanselmann | exclusive lock will be acquired
|
640 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
641 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
642 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
643 | 9216a9f7 | Michael Hanselmann |
|
644 | 9216a9f7 | Michael Hanselmann | """
|
645 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
646 | 9216a9f7 | Michael Hanselmann | |
647 | 84e344d4 | Michael Hanselmann | # We cannot acquire the lock if we already have it
|
648 | 7f93570a | Iustin Pop | assert not self.__is_owned(), ("double acquire() on a non-recursive lock" |
649 | 7f93570a | Iustin Pop | " %s" % self.name) |
650 | 84e344d4 | Michael Hanselmann | |
651 | 887c7aa6 | Michael Hanselmann | # Remove empty entries from queue
|
652 | 887c7aa6 | Michael Hanselmann | self.__find_first_pending_queue()
|
653 | 887c7aa6 | Michael Hanselmann | |
654 | 84e344d4 | Michael Hanselmann | # Check whether someone else holds the lock or there are pending acquires.
|
655 | 84e344d4 | Michael Hanselmann | if not self.__pending and self.__can_acquire(shared): |
656 | 84e344d4 | Michael Hanselmann | # Apparently not, can acquire lock directly.
|
657 | 84e344d4 | Michael Hanselmann | self.__do_acquire(shared)
|
658 | 84e344d4 | Michael Hanselmann | return True |
659 | 9216a9f7 | Michael Hanselmann | |
660 | 887c7aa6 | Michael Hanselmann | prioqueue = self.__pending_by_prio.get(priority, None) |
661 | 9216a9f7 | Michael Hanselmann | |
662 | 887c7aa6 | Michael Hanselmann | if shared:
|
663 | 887c7aa6 | Michael Hanselmann | # Try to re-use condition for shared acquire
|
664 | 887c7aa6 | Michael Hanselmann | wait_condition = self.__pending_shared.get(priority, None) |
665 | 887c7aa6 | Michael Hanselmann | assert (wait_condition is None or |
666 | 887c7aa6 | Michael Hanselmann | (wait_condition.shared and wait_condition in prioqueue)) |
667 | 84e344d4 | Michael Hanselmann | else:
|
668 | 887c7aa6 | Michael Hanselmann | wait_condition = None
|
669 | 887c7aa6 | Michael Hanselmann | |
670 | 887c7aa6 | Michael Hanselmann | if wait_condition is None: |
671 | 887c7aa6 | Michael Hanselmann | if prioqueue is None: |
672 | 887c7aa6 | Michael Hanselmann | assert priority not in self.__pending_by_prio |
673 | 887c7aa6 | Michael Hanselmann | |
674 | 887c7aa6 | Michael Hanselmann | prioqueue = [] |
675 | 887c7aa6 | Michael Hanselmann | heapq.heappush(self.__pending, (priority, prioqueue))
|
676 | 887c7aa6 | Michael Hanselmann | self.__pending_by_prio[priority] = prioqueue
|
677 | 887c7aa6 | Michael Hanselmann | |
678 | 887c7aa6 | Michael Hanselmann | wait_condition = self.__condition_class(self.__lock, shared) |
679 | 887c7aa6 | Michael Hanselmann | prioqueue.append(wait_condition) |
680 | 887c7aa6 | Michael Hanselmann | |
681 | 887c7aa6 | Michael Hanselmann | if shared:
|
682 | 887c7aa6 | Michael Hanselmann | # Keep reference for further shared acquires on same priority. This is
|
683 | 887c7aa6 | Michael Hanselmann | # better than trying to find it in the list of pending acquires.
|
684 | 887c7aa6 | Michael Hanselmann | assert priority not in self.__pending_shared |
685 | 887c7aa6 | Michael Hanselmann | self.__pending_shared[priority] = wait_condition
|
686 | 84e344d4 | Michael Hanselmann | |
687 | 84e344d4 | Michael Hanselmann | try:
|
688 | 84e344d4 | Michael Hanselmann | # Wait until we become the topmost acquire in the queue or the timeout
|
689 | 84e344d4 | Michael Hanselmann | # expires.
|
690 | 887c7aa6 | Michael Hanselmann | # TODO: Decrease timeout with spurious notifications
|
691 | 84e344d4 | Michael Hanselmann | while not (self.__is_on_top(wait_condition) and |
692 | 84e344d4 | Michael Hanselmann | self.__can_acquire(shared)):
|
693 | 84e344d4 | Michael Hanselmann | # Wait for notification
|
694 | 84e344d4 | Michael Hanselmann | wait_condition.wait(timeout) |
695 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
696 | 84e344d4 | Michael Hanselmann | |
697 | 84e344d4 | Michael Hanselmann | # A lot of code assumes blocking acquires always succeed. Loop
|
698 | 84e344d4 | Michael Hanselmann | # internally for that case.
|
699 | 84e344d4 | Michael Hanselmann | if timeout is not None: |
700 | 84e344d4 | Michael Hanselmann | break
|
701 | 84e344d4 | Michael Hanselmann | |
702 | 84e344d4 | Michael Hanselmann | if self.__is_on_top(wait_condition) and self.__can_acquire(shared): |
703 | 84e344d4 | Michael Hanselmann | self.__do_acquire(shared)
|
704 | 84e344d4 | Michael Hanselmann | return True |
705 | 9216a9f7 | Michael Hanselmann | finally:
|
706 | 84e344d4 | Michael Hanselmann | # Remove condition from queue if there are no more waiters
|
707 | 887c7aa6 | Michael Hanselmann | if not wait_condition.has_waiting(): |
708 | 887c7aa6 | Michael Hanselmann | prioqueue.remove(wait_condition) |
709 | 887c7aa6 | Michael Hanselmann | if wait_condition.shared:
|
710 | 113359fe | Michael Hanselmann | # Remove from list of shared acquires if it wasn't while releasing
|
711 | 113359fe | Michael Hanselmann | # (e.g. on lock deletion)
|
712 | 113359fe | Michael Hanselmann | self.__pending_shared.pop(priority, None) |
713 | 9216a9f7 | Michael Hanselmann | |
714 | 84e344d4 | Michael Hanselmann | return False |
715 | 9216a9f7 | Michael Hanselmann | |
716 | 7100c2fa | Michael Hanselmann | def acquire(self, shared=0, timeout=None, priority=None, |
717 | 887c7aa6 | Michael Hanselmann | test_notify=None):
|
718 | 162c1c1f | Guido Trotter | """Acquire a shared lock.
|
719 | 162c1c1f | Guido Trotter |
|
720 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
721 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default an
|
722 | c41eea6e | Iustin Pop | exclusive lock will be acquired
|
723 | 84e344d4 | Michael Hanselmann | @type timeout: float
|
724 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
725 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
726 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
727 | 008b92fa | Michael Hanselmann | @type test_notify: callable or None
|
728 | 008b92fa | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
729 | 162c1c1f | Guido Trotter |
|
730 | 162c1c1f | Guido Trotter | """
|
731 | 7100c2fa | Michael Hanselmann | if priority is None: |
732 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
733 | 7100c2fa | Michael Hanselmann | |
734 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
735 | 162c1c1f | Guido Trotter | try:
|
736 | 008b92fa | Michael Hanselmann | # We already got the lock, notify now
|
737 | 008b92fa | Michael Hanselmann | if __debug__ and callable(test_notify): |
738 | 008b92fa | Michael Hanselmann | test_notify() |
739 | 008b92fa | Michael Hanselmann | |
740 | 887c7aa6 | Michael Hanselmann | return self.__acquire_unlocked(shared, timeout, priority) |
741 | 162c1c1f | Guido Trotter | finally:
|
742 | 162c1c1f | Guido Trotter | self.__lock.release()
|
743 | 162c1c1f | Guido Trotter | |
744 | 3dbe3ddf | Michael Hanselmann | def downgrade(self): |
745 | 3dbe3ddf | Michael Hanselmann | """Changes the lock mode from exclusive to shared.
|
746 | 3dbe3ddf | Michael Hanselmann |
|
747 | 3dbe3ddf | Michael Hanselmann | Pending acquires in shared mode on the same priority will go ahead.
|
748 | 3dbe3ddf | Michael Hanselmann |
|
749 | 3dbe3ddf | Michael Hanselmann | """
|
750 | 3dbe3ddf | Michael Hanselmann | self.__lock.acquire()
|
751 | 3dbe3ddf | Michael Hanselmann | try:
|
752 | 3dbe3ddf | Michael Hanselmann | assert self.__is_owned(), "Lock must be owned" |
753 | 3dbe3ddf | Michael Hanselmann | |
754 | 3dbe3ddf | Michael Hanselmann | if self.__is_exclusive(): |
755 | 3dbe3ddf | Michael Hanselmann | # Do nothing if the lock is already acquired in shared mode
|
756 | 3dbe3ddf | Michael Hanselmann | self.__exc = None |
757 | 3dbe3ddf | Michael Hanselmann | self.__do_acquire(1) |
758 | 3dbe3ddf | Michael Hanselmann | |
759 | 3dbe3ddf | Michael Hanselmann | # Important: pending shared acquires should only jump ahead if there
|
760 | 3dbe3ddf | Michael Hanselmann | # was a transition from exclusive to shared, otherwise an owner of a
|
761 | 3dbe3ddf | Michael Hanselmann | # shared lock can keep calling this function to push incoming shared
|
762 | 3dbe3ddf | Michael Hanselmann | # acquires
|
763 | 3dbe3ddf | Michael Hanselmann | (priority, prioqueue) = self.__find_first_pending_queue()
|
764 | 3dbe3ddf | Michael Hanselmann | if prioqueue:
|
765 | 3dbe3ddf | Michael Hanselmann | # Is there a pending shared acquire on this priority?
|
766 | 3dbe3ddf | Michael Hanselmann | cond = self.__pending_shared.pop(priority, None) |
767 | 3dbe3ddf | Michael Hanselmann | if cond:
|
768 | 3dbe3ddf | Michael Hanselmann | assert cond.shared
|
769 | 3dbe3ddf | Michael Hanselmann | assert cond in prioqueue |
770 | 3dbe3ddf | Michael Hanselmann | |
771 | 3dbe3ddf | Michael Hanselmann | # Ensure shared acquire is on top of queue
|
772 | 3dbe3ddf | Michael Hanselmann | if len(prioqueue) > 1: |
773 | 3dbe3ddf | Michael Hanselmann | prioqueue.remove(cond) |
774 | 3dbe3ddf | Michael Hanselmann | prioqueue.insert(0, cond)
|
775 | 3dbe3ddf | Michael Hanselmann | |
776 | 3dbe3ddf | Michael Hanselmann | # Notify
|
777 | 3dbe3ddf | Michael Hanselmann | cond.notifyAll() |
778 | 3dbe3ddf | Michael Hanselmann | |
779 | 3dbe3ddf | Michael Hanselmann | assert not self.__is_exclusive() |
780 | 3dbe3ddf | Michael Hanselmann | assert self.__is_sharer() |
781 | 3dbe3ddf | Michael Hanselmann | |
782 | 3dbe3ddf | Michael Hanselmann | return True |
783 | 3dbe3ddf | Michael Hanselmann | finally:
|
784 | 3dbe3ddf | Michael Hanselmann | self.__lock.release()
|
785 | 3dbe3ddf | Michael Hanselmann | |
786 | 162c1c1f | Guido Trotter | def release(self): |
787 | 162c1c1f | Guido Trotter | """Release a Shared Lock.
|
788 | 162c1c1f | Guido Trotter |
|
789 | 162c1c1f | Guido Trotter | You must have acquired the lock, either in shared or in exclusive mode,
|
790 | 162c1c1f | Guido Trotter | before calling this function.
|
791 | 162c1c1f | Guido Trotter |
|
792 | 162c1c1f | Guido Trotter | """
|
793 | 162c1c1f | Guido Trotter | self.__lock.acquire()
|
794 | 162c1c1f | Guido Trotter | try:
|
795 | 84e344d4 | Michael Hanselmann | assert self.__is_exclusive() or self.__is_sharer(), \ |
796 | 84e344d4 | Michael Hanselmann | "Cannot release non-owned lock"
|
797 | 84e344d4 | Michael Hanselmann | |
798 | 162c1c1f | Guido Trotter | # Autodetect release type
|
799 | 162c1c1f | Guido Trotter | if self.__is_exclusive(): |
800 | 162c1c1f | Guido Trotter | self.__exc = None |
801 | 84e344d4 | Michael Hanselmann | else:
|
802 | 162c1c1f | Guido Trotter | self.__shr.remove(threading.currentThread())
|
803 | 162c1c1f | Guido Trotter | |
804 | 84e344d4 | Michael Hanselmann | # Notify topmost condition in queue
|
805 | 113359fe | Michael Hanselmann | (priority, prioqueue) = self.__find_first_pending_queue()
|
806 | 887c7aa6 | Michael Hanselmann | if prioqueue:
|
807 | 113359fe | Michael Hanselmann | cond = prioqueue[0]
|
808 | 113359fe | Michael Hanselmann | cond.notifyAll() |
809 | 113359fe | Michael Hanselmann | if cond.shared:
|
810 | 113359fe | Michael Hanselmann | # Prevent further shared acquires from sneaking in while waiters are
|
811 | 113359fe | Michael Hanselmann | # notified
|
812 | 113359fe | Michael Hanselmann | self.__pending_shared.pop(priority, None) |
813 | 162c1c1f | Guido Trotter | |
814 | 162c1c1f | Guido Trotter | finally:
|
815 | 162c1c1f | Guido Trotter | self.__lock.release()
|
816 | 162c1c1f | Guido Trotter | |
817 | 7100c2fa | Michael Hanselmann | def delete(self, timeout=None, priority=None): |
818 | a95fd5d7 | Guido Trotter | """Delete a Shared Lock.
|
819 | a95fd5d7 | Guido Trotter |
|
820 | a95fd5d7 | Guido Trotter | This operation will declare the lock for removal. First the lock will be
|
821 | a95fd5d7 | Guido Trotter | acquired in exclusive mode if you don't already own it, then the lock
|
822 | a95fd5d7 | Guido Trotter | will be put in a state where any future and pending acquire() fail.
|
823 | a95fd5d7 | Guido Trotter |
|
824 | 84e344d4 | Michael Hanselmann | @type timeout: float
|
825 | 84e344d4 | Michael Hanselmann | @param timeout: maximum waiting time before giving up
|
826 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
827 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
828 | a95fd5d7 | Guido Trotter |
|
829 | a95fd5d7 | Guido Trotter | """
|
830 | 7100c2fa | Michael Hanselmann | if priority is None: |
831 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
832 | 7100c2fa | Michael Hanselmann | |
833 | a95fd5d7 | Guido Trotter | self.__lock.acquire()
|
834 | a95fd5d7 | Guido Trotter | try:
|
835 | 84e344d4 | Michael Hanselmann | assert not self.__is_sharer(), "Cannot delete() a lock while sharing it" |
836 | 84e344d4 | Michael Hanselmann | |
837 | 84e344d4 | Michael Hanselmann | self.__check_deleted()
|
838 | a95fd5d7 | Guido Trotter | |
839 | 84e344d4 | Michael Hanselmann | # The caller is allowed to hold the lock exclusively already.
|
840 | 84e344d4 | Michael Hanselmann | acquired = self.__is_exclusive()
|
841 | a95fd5d7 | Guido Trotter | |
842 | 84e344d4 | Michael Hanselmann | if not acquired: |
843 | 887c7aa6 | Michael Hanselmann | acquired = self.__acquire_unlocked(0, timeout, priority) |
844 | a66bd91b | Michael Hanselmann | |
845 | a66bd91b | Michael Hanselmann | assert self.__is_exclusive() and not self.__is_sharer(), \ |
846 | a66bd91b | Michael Hanselmann | "Lock wasn't acquired in exclusive mode"
|
847 | 84e344d4 | Michael Hanselmann | |
848 | 84e344d4 | Michael Hanselmann | if acquired:
|
849 | 84e344d4 | Michael Hanselmann | self.__deleted = True |
850 | 84e344d4 | Michael Hanselmann | self.__exc = None |
851 | a95fd5d7 | Guido Trotter | |
852 | 19b9ba9a | Michael Hanselmann | assert not (self.__exc or self.__shr), "Found owner during deletion" |
853 | 19b9ba9a | Michael Hanselmann | |
854 | 84e344d4 | Michael Hanselmann | # Notify all acquires. They'll throw an error.
|
855 | 887c7aa6 | Michael Hanselmann | for (_, prioqueue) in self.__pending: |
856 | 887c7aa6 | Michael Hanselmann | for cond in prioqueue: |
857 | 887c7aa6 | Michael Hanselmann | cond.notifyAll() |
858 | 887c7aa6 | Michael Hanselmann | |
859 | 887c7aa6 | Michael Hanselmann | assert self.__deleted |
860 | a95fd5d7 | Guido Trotter | |
861 | 84e344d4 | Michael Hanselmann | return acquired
|
862 | a95fd5d7 | Guido Trotter | finally:
|
863 | a95fd5d7 | Guido Trotter | self.__lock.release()
|
864 | a95fd5d7 | Guido Trotter | |
865 | 1a4e32d0 | Guido Trotter | def _release_save(self): |
866 | 1a4e32d0 | Guido Trotter | shared = self.__is_sharer()
|
867 | 1a4e32d0 | Guido Trotter | self.release()
|
868 | 1a4e32d0 | Guido Trotter | return shared
|
869 | 1a4e32d0 | Guido Trotter | |
870 | 1a4e32d0 | Guido Trotter | def _acquire_restore(self, shared): |
871 | 1a4e32d0 | Guido Trotter | self.acquire(shared=shared)
|
872 | 1a4e32d0 | Guido Trotter | |
873 | aaae9bc0 | Guido Trotter | |
874 | f12eadb3 | Iustin Pop | # Whenever we want to acquire a full LockSet we pass None as the value
|
875 | 5bbd3f7f | Michael Hanselmann | # to acquire. Hide this behind this nicely named constant.
|
876 | e310b019 | Guido Trotter | ALL_SET = None
|
877 | e310b019 | Guido Trotter | |
878 | e310b019 | Guido Trotter | |
879 | 5aab242c | Michael Hanselmann | class _AcquireTimeout(Exception): |
880 | 5aab242c | Michael Hanselmann | """Internal exception to abort an acquire on a timeout.
|
881 | 5aab242c | Michael Hanselmann |
|
882 | 5aab242c | Michael Hanselmann | """
|
883 | 5aab242c | Michael Hanselmann | |
884 | 5aab242c | Michael Hanselmann | |
885 | aaae9bc0 | Guido Trotter | class LockSet: |
886 | aaae9bc0 | Guido Trotter | """Implements a set of locks.
|
887 | aaae9bc0 | Guido Trotter |
|
888 | aaae9bc0 | Guido Trotter | This abstraction implements a set of shared locks for the same resource type,
|
889 | aaae9bc0 | Guido Trotter | distinguished by name. The user can lock a subset of the resources and the
|
890 | aaae9bc0 | Guido Trotter | LockSet will take care of acquiring the locks always in the same order, thus
|
891 | aaae9bc0 | Guido Trotter | preventing deadlock.
|
892 | aaae9bc0 | Guido Trotter |
|
893 | aaae9bc0 | Guido Trotter | All the locks needed in the same set must be acquired together, though.
|
894 | aaae9bc0 | Guido Trotter |
|
895 | 7f93570a | Iustin Pop | @type name: string
|
896 | 7f93570a | Iustin Pop | @ivar name: the name of the lockset
|
897 | 7f93570a | Iustin Pop |
|
898 | aaae9bc0 | Guido Trotter | """
|
899 | 19b9ba9a | Michael Hanselmann | def __init__(self, members, name, monitor=None): |
900 | aaae9bc0 | Guido Trotter | """Constructs a new LockSet.
|
901 | aaae9bc0 | Guido Trotter |
|
902 | ec44d893 | Guido Trotter | @type members: list of strings
|
903 | c41eea6e | Iustin Pop | @param members: initial members of the set
|
904 | 19b9ba9a | Michael Hanselmann | @type monitor: L{LockMonitor}
|
905 | 19b9ba9a | Michael Hanselmann | @param monitor: Lock monitor with which to register member locks
|
906 | aaae9bc0 | Guido Trotter |
|
907 | aaae9bc0 | Guido Trotter | """
|
908 | 7f93570a | Iustin Pop | assert members is not None, "members parameter is not a list" |
909 | 7f93570a | Iustin Pop | self.name = name
|
910 | 7f93570a | Iustin Pop | |
911 | 19b9ba9a | Michael Hanselmann | # Lock monitor
|
912 | 19b9ba9a | Michael Hanselmann | self.__monitor = monitor
|
913 | 19b9ba9a | Michael Hanselmann | |
914 | c307ee34 | Michael Hanselmann | # Used internally to guarantee coherency
|
915 | c307ee34 | Michael Hanselmann | self.__lock = SharedLock(self._GetLockName("[lockset]"), monitor=monitor) |
916 | aaae9bc0 | Guido Trotter | |
917 | aaae9bc0 | Guido Trotter | # The lockdict indexes the relationship name -> lock
|
918 | aaae9bc0 | Guido Trotter | # The order-of-locking is implied by the alphabetical order of names
|
919 | aaae9bc0 | Guido Trotter | self.__lockdict = {}
|
920 | aaae9bc0 | Guido Trotter | |
921 | 7f93570a | Iustin Pop | for mname in members: |
922 | 19b9ba9a | Michael Hanselmann | self.__lockdict[mname] = SharedLock(self._GetLockName(mname), |
923 | 19b9ba9a | Michael Hanselmann | monitor=monitor) |
924 | aaae9bc0 | Guido Trotter | |
925 | aaae9bc0 | Guido Trotter | # The owner dict contains the set of locks each thread owns. For
|
926 | aaae9bc0 | Guido Trotter | # performance each thread can access its own key without a global lock on
|
927 | aaae9bc0 | Guido Trotter | # this structure. It is paramount though that *no* other type of access is
|
928 | aaae9bc0 | Guido Trotter | # done to this structure (eg. no looping over its keys). *_owner helper
|
929 | aaae9bc0 | Guido Trotter | # function are defined to guarantee access is correct, but in general never
|
930 | aaae9bc0 | Guido Trotter | # do anything different than __owners[threading.currentThread()], or there
|
931 | aaae9bc0 | Guido Trotter | # will be trouble.
|
932 | aaae9bc0 | Guido Trotter | self.__owners = {}
|
933 | aaae9bc0 | Guido Trotter | |
934 | 4fb780d1 | Michael Hanselmann | def _GetLockName(self, mname): |
935 | 4fb780d1 | Michael Hanselmann | """Returns the name for a member lock.
|
936 | 4fb780d1 | Michael Hanselmann |
|
937 | 4fb780d1 | Michael Hanselmann | """
|
938 | 4fb780d1 | Michael Hanselmann | return "%s/%s" % (self.name, mname) |
939 | 4fb780d1 | Michael Hanselmann | |
940 | 3dbe3ddf | Michael Hanselmann | def _get_lock(self): |
941 | 3dbe3ddf | Michael Hanselmann | """Returns the lockset-internal lock.
|
942 | 3dbe3ddf | Michael Hanselmann |
|
943 | 3dbe3ddf | Michael Hanselmann | """
|
944 | 3dbe3ddf | Michael Hanselmann | return self.__lock |
945 | 3dbe3ddf | Michael Hanselmann | |
946 | 3dbe3ddf | Michael Hanselmann | def _get_lockdict(self): |
947 | 3dbe3ddf | Michael Hanselmann | """Returns the lockset-internal lock dictionary.
|
948 | 3dbe3ddf | Michael Hanselmann |
|
949 | 3dbe3ddf | Michael Hanselmann | Accessing this structure is only safe in single-thread usage or when the
|
950 | 3dbe3ddf | Michael Hanselmann | lockset-internal lock is held.
|
951 | 3dbe3ddf | Michael Hanselmann |
|
952 | 3dbe3ddf | Michael Hanselmann | """
|
953 | 3dbe3ddf | Michael Hanselmann | return self.__lockdict |
954 | 3dbe3ddf | Michael Hanselmann | |
955 | ee2b99e3 | Michael Hanselmann | def is_owned(self): |
956 | c6a622cf | Michael Hanselmann | """Is the current thread a current level owner?
|
957 | c6a622cf | Michael Hanselmann |
|
958 | c6a622cf | Michael Hanselmann | @note: Use L{check_owned} to check if a specific lock is held
|
959 | c6a622cf | Michael Hanselmann |
|
960 | c6a622cf | Michael Hanselmann | """
|
961 | aaae9bc0 | Guido Trotter | return threading.currentThread() in self.__owners |
962 | aaae9bc0 | Guido Trotter | |
963 | c6a622cf | Michael Hanselmann | def check_owned(self, names, shared=-1): |
964 | c6a622cf | Michael Hanselmann | """Check if locks are owned in a specific mode.
|
965 | c6a622cf | Michael Hanselmann |
|
966 | c6a622cf | Michael Hanselmann | @type names: sequence or string
|
967 | c6a622cf | Michael Hanselmann | @param names: Lock names (or a single lock name)
|
968 | c6a622cf | Michael Hanselmann | @param shared: See L{SharedLock.is_owned}
|
969 | c6a622cf | Michael Hanselmann | @rtype: bool
|
970 | c6a622cf | Michael Hanselmann | @note: Use L{is_owned} to check if the current thread holds I{any} lock and
|
971 | c6a622cf | Michael Hanselmann | L{list_owned} to get the names of all owned locks
|
972 | c6a622cf | Michael Hanselmann |
|
973 | c6a622cf | Michael Hanselmann | """
|
974 | c6a622cf | Michael Hanselmann | if isinstance(names, basestring): |
975 | c6a622cf | Michael Hanselmann | names = [names] |
976 | c6a622cf | Michael Hanselmann | |
977 | c6a622cf | Michael Hanselmann | # Avoid check if no locks are owned anyway
|
978 | c6a622cf | Michael Hanselmann | if names and self.is_owned(): |
979 | c6a622cf | Michael Hanselmann | candidates = [] |
980 | c6a622cf | Michael Hanselmann | |
981 | c6a622cf | Michael Hanselmann | # Gather references to all locks (in case they're deleted in the meantime)
|
982 | c6a622cf | Michael Hanselmann | for lname in names: |
983 | c6a622cf | Michael Hanselmann | try:
|
984 | c6a622cf | Michael Hanselmann | lock = self.__lockdict[lname]
|
985 | c6a622cf | Michael Hanselmann | except KeyError: |
986 | c6a622cf | Michael Hanselmann | raise errors.LockError("Non-existing lock '%s' in set '%s' (it may" |
987 | c6a622cf | Michael Hanselmann | " have been removed)" % (lname, self.name)) |
988 | c6a622cf | Michael Hanselmann | else:
|
989 | c6a622cf | Michael Hanselmann | candidates.append(lock) |
990 | c6a622cf | Michael Hanselmann | |
991 | c6a622cf | Michael Hanselmann | return compat.all(lock.is_owned(shared=shared) for lock in candidates) |
992 | c6a622cf | Michael Hanselmann | else:
|
993 | c6a622cf | Michael Hanselmann | return False |
994 | c6a622cf | Michael Hanselmann | |
995 | b2dabfd6 | Guido Trotter | def _add_owned(self, name=None): |
996 | aaae9bc0 | Guido Trotter | """Note the current thread owns the given lock"""
|
997 | b2dabfd6 | Guido Trotter | if name is None: |
998 | ee2b99e3 | Michael Hanselmann | if not self.is_owned(): |
999 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()] = set() |
1000 | aaae9bc0 | Guido Trotter | else:
|
1001 | ee2b99e3 | Michael Hanselmann | if self.is_owned(): |
1002 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()].add(name)
|
1003 | b2dabfd6 | Guido Trotter | else:
|
1004 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()] = set([name]) |
1005 | b2dabfd6 | Guido Trotter | |
1006 | b2dabfd6 | Guido Trotter | def _del_owned(self, name=None): |
1007 | aaae9bc0 | Guido Trotter | """Note the current thread owns the given lock"""
|
1008 | aaae9bc0 | Guido Trotter | |
1009 | ee2b99e3 | Michael Hanselmann | assert not (name is None and self.__lock.is_owned()), \ |
1010 | e4335b5b | Michael Hanselmann | "Cannot hold internal lock when deleting owner status"
|
1011 | e4335b5b | Michael Hanselmann | |
1012 | b2dabfd6 | Guido Trotter | if name is not None: |
1013 | b2dabfd6 | Guido Trotter | self.__owners[threading.currentThread()].remove(name)
|
1014 | b2dabfd6 | Guido Trotter | |
1015 | b2dabfd6 | Guido Trotter | # Only remove the key if we don't hold the set-lock as well
|
1016 | ee2b99e3 | Michael Hanselmann | if (not self.__lock.is_owned() and |
1017 | b2dabfd6 | Guido Trotter | not self.__owners[threading.currentThread()]): |
1018 | aaae9bc0 | Guido Trotter | del self.__owners[threading.currentThread()] |
1019 | aaae9bc0 | Guido Trotter | |
1020 | ee2b99e3 | Michael Hanselmann | def list_owned(self): |
1021 | aaae9bc0 | Guido Trotter | """Get the set of resource names owned by the current thread"""
|
1022 | ee2b99e3 | Michael Hanselmann | if self.is_owned(): |
1023 | aaae9bc0 | Guido Trotter | return self.__owners[threading.currentThread()].copy() |
1024 | aaae9bc0 | Guido Trotter | else:
|
1025 | aaae9bc0 | Guido Trotter | return set() |
1026 | aaae9bc0 | Guido Trotter | |
1027 | 5aab242c | Michael Hanselmann | def _release_and_delete_owned(self): |
1028 | 5aab242c | Michael Hanselmann | """Release and delete all resources owned by the current thread"""
|
1029 | ee2b99e3 | Michael Hanselmann | for lname in self.list_owned(): |
1030 | 56452af7 | Michael Hanselmann | lock = self.__lockdict[lname]
|
1031 | ee2b99e3 | Michael Hanselmann | if lock.is_owned():
|
1032 | 56452af7 | Michael Hanselmann | lock.release() |
1033 | 5aab242c | Michael Hanselmann | self._del_owned(name=lname)
|
1034 | 5aab242c | Michael Hanselmann | |
1035 | aaae9bc0 | Guido Trotter | def __names(self): |
1036 | aaae9bc0 | Guido Trotter | """Return the current set of names.
|
1037 | aaae9bc0 | Guido Trotter |
|
1038 | aaae9bc0 | Guido Trotter | Only call this function while holding __lock and don't iterate on the
|
1039 | aaae9bc0 | Guido Trotter | result after releasing the lock.
|
1040 | aaae9bc0 | Guido Trotter |
|
1041 | aaae9bc0 | Guido Trotter | """
|
1042 | 0cf257c5 | Guido Trotter | return self.__lockdict.keys() |
1043 | aaae9bc0 | Guido Trotter | |
1044 | aaae9bc0 | Guido Trotter | def _names(self): |
1045 | aaae9bc0 | Guido Trotter | """Return a copy of the current set of elements.
|
1046 | aaae9bc0 | Guido Trotter |
|
1047 | aaae9bc0 | Guido Trotter | Used only for debugging purposes.
|
1048 | cdb08f44 | Michael Hanselmann |
|
1049 | aaae9bc0 | Guido Trotter | """
|
1050 | d4803c24 | Guido Trotter | # If we don't already own the set-level lock acquired
|
1051 | d4803c24 | Guido Trotter | # we'll get it and note we need to release it later.
|
1052 | d4803c24 | Guido Trotter | release_lock = False
|
1053 | ee2b99e3 | Michael Hanselmann | if not self.__lock.is_owned(): |
1054 | d4803c24 | Guido Trotter | release_lock = True
|
1055 | d4803c24 | Guido Trotter | self.__lock.acquire(shared=1) |
1056 | aaae9bc0 | Guido Trotter | try:
|
1057 | aaae9bc0 | Guido Trotter | result = self.__names()
|
1058 | aaae9bc0 | Guido Trotter | finally:
|
1059 | d4803c24 | Guido Trotter | if release_lock:
|
1060 | d4803c24 | Guido Trotter | self.__lock.release()
|
1061 | 0cf257c5 | Guido Trotter | return set(result) |
1062 | aaae9bc0 | Guido Trotter | |
1063 | 7100c2fa | Michael Hanselmann | def acquire(self, names, timeout=None, shared=0, priority=None, |
1064 | 887c7aa6 | Michael Hanselmann | test_notify=None):
|
1065 | aaae9bc0 | Guido Trotter | """Acquire a set of resource locks.
|
1066 | aaae9bc0 | Guido Trotter |
|
1067 | ec44d893 | Guido Trotter | @type names: list of strings (or string)
|
1068 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be acquired
|
1069 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1070 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1071 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default an
|
1072 | c41eea6e | Iustin Pop | exclusive lock will be acquired
|
1073 | 5aab242c | Michael Hanselmann | @type timeout: float or None
|
1074 | 5e0a6daf | Michael Hanselmann | @param timeout: Maximum time to acquire all locks
|
1075 | 887c7aa6 | Michael Hanselmann | @type priority: integer
|
1076 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring locks
|
1077 | 5aab242c | Michael Hanselmann | @type test_notify: callable or None
|
1078 | 5aab242c | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
1079 | aaae9bc0 | Guido Trotter |
|
1080 | 5aab242c | Michael Hanselmann | @return: Set of all locks successfully acquired or None in case of timeout
|
1081 | aaae9bc0 | Guido Trotter |
|
1082 | c41eea6e | Iustin Pop | @raise errors.LockError: when any lock we try to acquire has
|
1083 | c41eea6e | Iustin Pop | been deleted before we succeed. In this case none of the
|
1084 | c41eea6e | Iustin Pop | locks requested will be acquired.
|
1085 | aaae9bc0 | Guido Trotter |
|
1086 | aaae9bc0 | Guido Trotter | """
|
1087 | 5aab242c | Michael Hanselmann | assert timeout is None or timeout >= 0.0 |
1088 | aaae9bc0 | Guido Trotter | |
1089 | aaae9bc0 | Guido Trotter | # Check we don't already own locks at this level
|
1090 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned(), ("Cannot acquire locks in the same set twice" |
1091 | ee2b99e3 | Michael Hanselmann | " (lockset %s)" % self.name) |
1092 | aaae9bc0 | Guido Trotter | |
1093 | 7100c2fa | Michael Hanselmann | if priority is None: |
1094 | 7100c2fa | Michael Hanselmann | priority = _DEFAULT_PRIORITY |
1095 | 7100c2fa | Michael Hanselmann | |
1096 | 5aab242c | Michael Hanselmann | # We need to keep track of how long we spent waiting for a lock. The
|
1097 | 5aab242c | Michael Hanselmann | # timeout passed to this function is over all lock acquires.
|
1098 | 557838c1 | Renรฉ Nussbaumer | running_timeout = utils.RunningTimeout(timeout, False)
|
1099 | 5aab242c | Michael Hanselmann | |
1100 | 806e20fd | Guido Trotter | try:
|
1101 | 76e2f08a | Michael Hanselmann | if names is not None: |
1102 | 5aab242c | Michael Hanselmann | # Support passing in a single resource to acquire rather than many
|
1103 | 5aab242c | Michael Hanselmann | if isinstance(names, basestring): |
1104 | 5aab242c | Michael Hanselmann | names = [names] |
1105 | 5aab242c | Michael Hanselmann | |
1106 | 887c7aa6 | Michael Hanselmann | return self.__acquire_inner(names, False, shared, priority, |
1107 | 7e8841bd | Michael Hanselmann | running_timeout.Remaining, test_notify) |
1108 | 76e2f08a | Michael Hanselmann | |
1109 | 76e2f08a | Michael Hanselmann | else:
|
1110 | 76e2f08a | Michael Hanselmann | # If no names are given acquire the whole set by not letting new names
|
1111 | 76e2f08a | Michael Hanselmann | # being added before we release, and getting the current list of names.
|
1112 | 76e2f08a | Michael Hanselmann | # Some of them may then be deleted later, but we'll cope with this.
|
1113 | 76e2f08a | Michael Hanselmann | #
|
1114 | 76e2f08a | Michael Hanselmann | # We'd like to acquire this lock in a shared way, as it's nice if
|
1115 | 887c7aa6 | Michael Hanselmann | # everybody else can use the instances at the same time. If we are
|
1116 | 76e2f08a | Michael Hanselmann | # acquiring them exclusively though they won't be able to do this
|
1117 | 76e2f08a | Michael Hanselmann | # anyway, though, so we'll get the list lock exclusively as well in
|
1118 | 76e2f08a | Michael Hanselmann | # order to be able to do add() on the set while owning it.
|
1119 | 887c7aa6 | Michael Hanselmann | if not self.__lock.acquire(shared=shared, priority=priority, |
1120 | 7e8841bd | Michael Hanselmann | timeout=running_timeout.Remaining()): |
1121 | 76e2f08a | Michael Hanselmann | raise _AcquireTimeout()
|
1122 | 76e2f08a | Michael Hanselmann | try:
|
1123 | 76e2f08a | Michael Hanselmann | # note we own the set-lock
|
1124 | 76e2f08a | Michael Hanselmann | self._add_owned()
|
1125 | 76e2f08a | Michael Hanselmann | |
1126 | 887c7aa6 | Michael Hanselmann | return self.__acquire_inner(self.__names(), True, shared, priority, |
1127 | 7e8841bd | Michael Hanselmann | running_timeout.Remaining, test_notify) |
1128 | 76e2f08a | Michael Hanselmann | except:
|
1129 | 76e2f08a | Michael Hanselmann | # We shouldn't have problems adding the lock to the owners list, but
|
1130 | 76e2f08a | Michael Hanselmann | # if we did we'll try to release this lock and re-raise exception.
|
1131 | 76e2f08a | Michael Hanselmann | # Of course something is going to be really wrong, after this.
|
1132 | 5aab242c | Michael Hanselmann | self.__lock.release()
|
1133 | 76e2f08a | Michael Hanselmann | self._del_owned()
|
1134 | 76e2f08a | Michael Hanselmann | raise
|
1135 | 5aab242c | Michael Hanselmann | |
1136 | 5aab242c | Michael Hanselmann | except _AcquireTimeout:
|
1137 | 5aab242c | Michael Hanselmann | return None |
1138 | aaae9bc0 | Guido Trotter | |
1139 | 887c7aa6 | Michael Hanselmann | def __acquire_inner(self, names, want_all, shared, priority, |
1140 | 887c7aa6 | Michael Hanselmann | timeout_fn, test_notify): |
1141 | 7e8841bd | Michael Hanselmann | """Inner logic for acquiring a number of locks.
|
1142 | 7e8841bd | Michael Hanselmann |
|
1143 | 7e8841bd | Michael Hanselmann | @param names: Names of the locks to be acquired
|
1144 | 7e8841bd | Michael Hanselmann | @param want_all: Whether all locks in the set should be acquired
|
1145 | 7e8841bd | Michael Hanselmann | @param shared: Whether to acquire in shared mode
|
1146 | 7e8841bd | Michael Hanselmann | @param timeout_fn: Function returning remaining timeout
|
1147 | 887c7aa6 | Michael Hanselmann | @param priority: Priority for acquiring locks
|
1148 | 7e8841bd | Michael Hanselmann | @param test_notify: Special callback function for unittesting
|
1149 | 76e2f08a | Michael Hanselmann |
|
1150 | 76e2f08a | Michael Hanselmann | """
|
1151 | 76e2f08a | Michael Hanselmann | acquire_list = [] |
1152 | 76e2f08a | Michael Hanselmann | |
1153 | 76e2f08a | Michael Hanselmann | # First we look the locks up on __lockdict. We have no way of being sure
|
1154 | 76e2f08a | Michael Hanselmann | # they will still be there after, but this makes it a lot faster should
|
1155 | 71e1863e | Michael Hanselmann | # just one of them be the already wrong. Using a sorted sequence to prevent
|
1156 | 71e1863e | Michael Hanselmann | # deadlocks.
|
1157 | 71e1863e | Michael Hanselmann | for lname in sorted(utils.UniqueSequence(names)): |
1158 | 76e2f08a | Michael Hanselmann | try:
|
1159 | 76e2f08a | Michael Hanselmann | lock = self.__lockdict[lname] # raises KeyError if lock is not there |
1160 | 76e2f08a | Michael Hanselmann | except KeyError: |
1161 | 76e2f08a | Michael Hanselmann | if want_all:
|
1162 | 76e2f08a | Michael Hanselmann | # We are acquiring all the set, it doesn't matter if this particular
|
1163 | 76e2f08a | Michael Hanselmann | # element is not there anymore.
|
1164 | 76e2f08a | Michael Hanselmann | continue
|
1165 | 76e2f08a | Michael Hanselmann | |
1166 | e1137eb6 | Michael Hanselmann | raise errors.LockError("Non-existing lock %s in set %s (it may have" |
1167 | e1137eb6 | Michael Hanselmann | " been removed)" % (lname, self.name)) |
1168 | 76e2f08a | Michael Hanselmann | |
1169 | 9b154270 | Michael Hanselmann | acquire_list.append((lname, lock)) |
1170 | 9b154270 | Michael Hanselmann | |
1171 | 76e2f08a | Michael Hanselmann | # This will hold the locknames we effectively acquired.
|
1172 | 76e2f08a | Michael Hanselmann | acquired = set()
|
1173 | 76e2f08a | Michael Hanselmann | |
1174 | 76e2f08a | Michael Hanselmann | try:
|
1175 | 76e2f08a | Michael Hanselmann | # Now acquire_list contains a sorted list of resources and locks we
|
1176 | 76e2f08a | Michael Hanselmann | # want. In order to get them we loop on this (private) list and
|
1177 | 76e2f08a | Michael Hanselmann | # acquire() them. We gave no real guarantee they will still exist till
|
1178 | 76e2f08a | Michael Hanselmann | # this is done but .acquire() itself is safe and will alert us if the
|
1179 | 76e2f08a | Michael Hanselmann | # lock gets deleted.
|
1180 | 76e2f08a | Michael Hanselmann | for (lname, lock) in acquire_list: |
1181 | 76e2f08a | Michael Hanselmann | if __debug__ and callable(test_notify): |
1182 | 76e2f08a | Michael Hanselmann | test_notify_fn = lambda: test_notify(lname)
|
1183 | 76e2f08a | Michael Hanselmann | else:
|
1184 | 76e2f08a | Michael Hanselmann | test_notify_fn = None
|
1185 | 76e2f08a | Michael Hanselmann | |
1186 | 76e2f08a | Michael Hanselmann | timeout = timeout_fn() |
1187 | 76e2f08a | Michael Hanselmann | |
1188 | 76e2f08a | Michael Hanselmann | try:
|
1189 | 76e2f08a | Michael Hanselmann | # raises LockError if the lock was deleted
|
1190 | 76e2f08a | Michael Hanselmann | acq_success = lock.acquire(shared=shared, timeout=timeout, |
1191 | 887c7aa6 | Michael Hanselmann | priority=priority, |
1192 | 76e2f08a | Michael Hanselmann | test_notify=test_notify_fn) |
1193 | 76e2f08a | Michael Hanselmann | except errors.LockError:
|
1194 | 76e2f08a | Michael Hanselmann | if want_all:
|
1195 | 76e2f08a | Michael Hanselmann | # We are acquiring all the set, it doesn't matter if this
|
1196 | 76e2f08a | Michael Hanselmann | # particular element is not there anymore.
|
1197 | 76e2f08a | Michael Hanselmann | continue
|
1198 | 76e2f08a | Michael Hanselmann | |
1199 | e1137eb6 | Michael Hanselmann | raise errors.LockError("Non-existing lock %s in set %s (it may" |
1200 | e1137eb6 | Michael Hanselmann | " have been removed)" % (lname, self.name)) |
1201 | 76e2f08a | Michael Hanselmann | |
1202 | 76e2f08a | Michael Hanselmann | if not acq_success: |
1203 | 76e2f08a | Michael Hanselmann | # Couldn't get lock or timeout occurred
|
1204 | 76e2f08a | Michael Hanselmann | if timeout is None: |
1205 | 76e2f08a | Michael Hanselmann | # This shouldn't happen as SharedLock.acquire(timeout=None) is
|
1206 | 76e2f08a | Michael Hanselmann | # blocking.
|
1207 | 7f93570a | Iustin Pop | raise errors.LockError("Failed to get lock %s (set %s)" % |
1208 | 7f93570a | Iustin Pop | (lname, self.name))
|
1209 | 76e2f08a | Michael Hanselmann | |
1210 | 76e2f08a | Michael Hanselmann | raise _AcquireTimeout()
|
1211 | 76e2f08a | Michael Hanselmann | |
1212 | 76e2f08a | Michael Hanselmann | try:
|
1213 | 76e2f08a | Michael Hanselmann | # now the lock cannot be deleted, we have it!
|
1214 | 76e2f08a | Michael Hanselmann | self._add_owned(name=lname)
|
1215 | 76e2f08a | Michael Hanselmann | acquired.add(lname) |
1216 | 76e2f08a | Michael Hanselmann | |
1217 | 76e2f08a | Michael Hanselmann | except:
|
1218 | 76e2f08a | Michael Hanselmann | # We shouldn't have problems adding the lock to the owners list, but
|
1219 | 76e2f08a | Michael Hanselmann | # if we did we'll try to release this lock and re-raise exception.
|
1220 | 76e2f08a | Michael Hanselmann | # Of course something is going to be really wrong after this.
|
1221 | ee2b99e3 | Michael Hanselmann | if lock.is_owned():
|
1222 | 76e2f08a | Michael Hanselmann | lock.release() |
1223 | 76e2f08a | Michael Hanselmann | raise
|
1224 | 76e2f08a | Michael Hanselmann | |
1225 | 76e2f08a | Michael Hanselmann | except:
|
1226 | 76e2f08a | Michael Hanselmann | # Release all owned locks
|
1227 | 76e2f08a | Michael Hanselmann | self._release_and_delete_owned()
|
1228 | 76e2f08a | Michael Hanselmann | raise
|
1229 | 76e2f08a | Michael Hanselmann | |
1230 | 0cc00929 | Guido Trotter | return acquired
|
1231 | aaae9bc0 | Guido Trotter | |
1232 | 3dbe3ddf | Michael Hanselmann | def downgrade(self, names=None): |
1233 | 3dbe3ddf | Michael Hanselmann | """Downgrade a set of resource locks from exclusive to shared mode.
|
1234 | 3dbe3ddf | Michael Hanselmann |
|
1235 | 3dbe3ddf | Michael Hanselmann | The locks must have been acquired in exclusive mode.
|
1236 | 3dbe3ddf | Michael Hanselmann |
|
1237 | 3dbe3ddf | Michael Hanselmann | """
|
1238 | ee2b99e3 | Michael Hanselmann | assert self.is_owned(), ("downgrade on lockset %s while not owning any" |
1239 | ee2b99e3 | Michael Hanselmann | " lock" % self.name) |
1240 | 3dbe3ddf | Michael Hanselmann | |
1241 | 3dbe3ddf | Michael Hanselmann | # Support passing in a single resource to downgrade rather than many
|
1242 | 3dbe3ddf | Michael Hanselmann | if isinstance(names, basestring): |
1243 | 3dbe3ddf | Michael Hanselmann | names = [names] |
1244 | 3dbe3ddf | Michael Hanselmann | |
1245 | ee2b99e3 | Michael Hanselmann | owned = self.list_owned()
|
1246 | 3dbe3ddf | Michael Hanselmann | |
1247 | 3dbe3ddf | Michael Hanselmann | if names is None: |
1248 | 3dbe3ddf | Michael Hanselmann | names = owned |
1249 | 3dbe3ddf | Michael Hanselmann | else:
|
1250 | 3dbe3ddf | Michael Hanselmann | names = set(names)
|
1251 | 3dbe3ddf | Michael Hanselmann | assert owned.issuperset(names), \
|
1252 | 3dbe3ddf | Michael Hanselmann | ("downgrade() on unheld resources %s (set %s)" %
|
1253 | 3dbe3ddf | Michael Hanselmann | (names.difference(owned), self.name))
|
1254 | 3dbe3ddf | Michael Hanselmann | |
1255 | 3dbe3ddf | Michael Hanselmann | for lockname in names: |
1256 | 3dbe3ddf | Michael Hanselmann | self.__lockdict[lockname].downgrade()
|
1257 | 3dbe3ddf | Michael Hanselmann | |
1258 | 3dbe3ddf | Michael Hanselmann | # Do we own the lockset in exclusive mode?
|
1259 | ee2b99e3 | Michael Hanselmann | if self.__lock.is_owned(shared=0): |
1260 | 3dbe3ddf | Michael Hanselmann | # Have all locks been downgraded?
|
1261 | ee2b99e3 | Michael Hanselmann | if not compat.any(lock.is_owned(shared=0) |
1262 | 3dbe3ddf | Michael Hanselmann | for lock in self.__lockdict.values()): |
1263 | 3dbe3ddf | Michael Hanselmann | self.__lock.downgrade()
|
1264 | ee2b99e3 | Michael Hanselmann | assert self.__lock.is_owned(shared=1) |
1265 | 3dbe3ddf | Michael Hanselmann | |
1266 | 3dbe3ddf | Michael Hanselmann | return True |
1267 | 3dbe3ddf | Michael Hanselmann | |
1268 | aaae9bc0 | Guido Trotter | def release(self, names=None): |
1269 | aaae9bc0 | Guido Trotter | """Release a set of resource locks, at the same level.
|
1270 | aaae9bc0 | Guido Trotter |
|
1271 | aaae9bc0 | Guido Trotter | You must have acquired the locks, either in shared or in exclusive mode,
|
1272 | aaae9bc0 | Guido Trotter | before releasing them.
|
1273 | aaae9bc0 | Guido Trotter |
|
1274 | ec44d893 | Guido Trotter | @type names: list of strings, or None
|
1275 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be released
|
1276 | c41eea6e | Iustin Pop | (defaults to all the locks acquired at that level).
|
1277 | aaae9bc0 | Guido Trotter |
|
1278 | aaae9bc0 | Guido Trotter | """
|
1279 | ee2b99e3 | Michael Hanselmann | assert self.is_owned(), ("release() on lock set %s while not owner" % |
1280 | ee2b99e3 | Michael Hanselmann | self.name)
|
1281 | aaae9bc0 | Guido Trotter | |
1282 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to release rather than many
|
1283 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1284 | aaae9bc0 | Guido Trotter | names = [names] |
1285 | aaae9bc0 | Guido Trotter | |
1286 | aaae9bc0 | Guido Trotter | if names is None: |
1287 | ee2b99e3 | Michael Hanselmann | names = self.list_owned()
|
1288 | aaae9bc0 | Guido Trotter | else:
|
1289 | aaae9bc0 | Guido Trotter | names = set(names)
|
1290 | ee2b99e3 | Michael Hanselmann | assert self.list_owned().issuperset(names), ( |
1291 | 7f93570a | Iustin Pop | "release() on unheld resources %s (set %s)" %
|
1292 | ee2b99e3 | Michael Hanselmann | (names.difference(self.list_owned()), self.name)) |
1293 | aaae9bc0 | Guido Trotter | |
1294 | 3b7ed473 | Guido Trotter | # First of all let's release the "all elements" lock, if set.
|
1295 | 3b7ed473 | Guido Trotter | # After this 'add' can work again
|
1296 | ee2b99e3 | Michael Hanselmann | if self.__lock.is_owned(): |
1297 | 3b7ed473 | Guido Trotter | self.__lock.release()
|
1298 | b2dabfd6 | Guido Trotter | self._del_owned()
|
1299 | 3b7ed473 | Guido Trotter | |
1300 | aaae9bc0 | Guido Trotter | for lockname in names: |
1301 | aaae9bc0 | Guido Trotter | # If we are sure the lock doesn't leave __lockdict without being
|
1302 | aaae9bc0 | Guido Trotter | # exclusively held we can do this...
|
1303 | aaae9bc0 | Guido Trotter | self.__lockdict[lockname].release()
|
1304 | b2dabfd6 | Guido Trotter | self._del_owned(name=lockname)
|
1305 | aaae9bc0 | Guido Trotter | |
1306 | aaae9bc0 | Guido Trotter | def add(self, names, acquired=0, shared=0): |
1307 | aaae9bc0 | Guido Trotter | """Add a new set of elements to the set
|
1308 | aaae9bc0 | Guido Trotter |
|
1309 | ec44d893 | Guido Trotter | @type names: list of strings
|
1310 | c41eea6e | Iustin Pop | @param names: names of the new elements to add
|
1311 | ec44d893 | Guido Trotter | @type acquired: integer (0/1) used as a boolean
|
1312 | c41eea6e | Iustin Pop | @param acquired: pre-acquire the new resource?
|
1313 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1314 | c41eea6e | Iustin Pop | @param shared: is the pre-acquisition shared?
|
1315 | aaae9bc0 | Guido Trotter |
|
1316 | aaae9bc0 | Guido Trotter | """
|
1317 | d2aff862 | Guido Trotter | # Check we don't already own locks at this level
|
1318 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned() or self.__lock.is_owned(shared=0), \ |
1319 | 7f93570a | Iustin Pop | ("Cannot add locks if the set %s is only partially owned, or shared" %
|
1320 | 7f93570a | Iustin Pop | self.name)
|
1321 | 3b7ed473 | Guido Trotter | |
1322 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to add rather than many
|
1323 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1324 | aaae9bc0 | Guido Trotter | names = [names] |
1325 | aaae9bc0 | Guido Trotter | |
1326 | ab62526c | Guido Trotter | # If we don't already own the set-level lock acquired in an exclusive way
|
1327 | 3b7ed473 | Guido Trotter | # we'll get it and note we need to release it later.
|
1328 | 3b7ed473 | Guido Trotter | release_lock = False
|
1329 | ee2b99e3 | Michael Hanselmann | if not self.__lock.is_owned(): |
1330 | 3b7ed473 | Guido Trotter | release_lock = True
|
1331 | 3b7ed473 | Guido Trotter | self.__lock.acquire()
|
1332 | 3b7ed473 | Guido Trotter | |
1333 | aaae9bc0 | Guido Trotter | try:
|
1334 | 0cf257c5 | Guido Trotter | invalid_names = set(self.__names()).intersection(names) |
1335 | aaae9bc0 | Guido Trotter | if invalid_names:
|
1336 | aaae9bc0 | Guido Trotter | # This must be an explicit raise, not an assert, because assert is
|
1337 | aaae9bc0 | Guido Trotter | # turned off when using optimization, and this can happen because of
|
1338 | aaae9bc0 | Guido Trotter | # concurrency even if the user doesn't want it.
|
1339 | 7f93570a | Iustin Pop | raise errors.LockError("duplicate add(%s) on lockset %s" % |
1340 | 7f93570a | Iustin Pop | (invalid_names, self.name))
|
1341 | aaae9bc0 | Guido Trotter | |
1342 | aaae9bc0 | Guido Trotter | for lockname in names: |
1343 | 19b9ba9a | Michael Hanselmann | lock = SharedLock(self._GetLockName(lockname), monitor=self.__monitor) |
1344 | aaae9bc0 | Guido Trotter | |
1345 | aaae9bc0 | Guido Trotter | if acquired:
|
1346 | 887c7aa6 | Michael Hanselmann | # No need for priority or timeout here as this lock has just been
|
1347 | 887c7aa6 | Michael Hanselmann | # created
|
1348 | aaae9bc0 | Guido Trotter | lock.acquire(shared=shared) |
1349 | aaae9bc0 | Guido Trotter | # now the lock cannot be deleted, we have it!
|
1350 | aaae9bc0 | Guido Trotter | try:
|
1351 | b2dabfd6 | Guido Trotter | self._add_owned(name=lockname)
|
1352 | aaae9bc0 | Guido Trotter | except:
|
1353 | aaae9bc0 | Guido Trotter | # We shouldn't have problems adding the lock to the owners list,
|
1354 | aaae9bc0 | Guido Trotter | # but if we did we'll try to release this lock and re-raise
|
1355 | aaae9bc0 | Guido Trotter | # exception. Of course something is going to be really wrong,
|
1356 | aaae9bc0 | Guido Trotter | # after this. On the other hand the lock hasn't been added to the
|
1357 | aaae9bc0 | Guido Trotter | # __lockdict yet so no other threads should be pending on it. This
|
1358 | aaae9bc0 | Guido Trotter | # release is just a safety measure.
|
1359 | aaae9bc0 | Guido Trotter | lock.release() |
1360 | aaae9bc0 | Guido Trotter | raise
|
1361 | aaae9bc0 | Guido Trotter | |
1362 | aaae9bc0 | Guido Trotter | self.__lockdict[lockname] = lock
|
1363 | aaae9bc0 | Guido Trotter | |
1364 | aaae9bc0 | Guido Trotter | finally:
|
1365 | 3b7ed473 | Guido Trotter | # Only release __lock if we were not holding it previously.
|
1366 | 3b7ed473 | Guido Trotter | if release_lock:
|
1367 | 3b7ed473 | Guido Trotter | self.__lock.release()
|
1368 | aaae9bc0 | Guido Trotter | |
1369 | aaae9bc0 | Guido Trotter | return True |
1370 | aaae9bc0 | Guido Trotter | |
1371 | 5e0a6daf | Michael Hanselmann | def remove(self, names): |
1372 | aaae9bc0 | Guido Trotter | """Remove elements from the lock set.
|
1373 | aaae9bc0 | Guido Trotter |
|
1374 | aaae9bc0 | Guido Trotter | You can either not hold anything in the lockset or already hold a superset
|
1375 | aaae9bc0 | Guido Trotter | of the elements you want to delete, exclusively.
|
1376 | aaae9bc0 | Guido Trotter |
|
1377 | ec44d893 | Guido Trotter | @type names: list of strings
|
1378 | c41eea6e | Iustin Pop | @param names: names of the resource to remove.
|
1379 | aaae9bc0 | Guido Trotter |
|
1380 | 5aab242c | Michael Hanselmann | @return: a list of locks which we removed; the list is always
|
1381 | c41eea6e | Iustin Pop | equal to the names list if we were holding all the locks
|
1382 | c41eea6e | Iustin Pop | exclusively
|
1383 | aaae9bc0 | Guido Trotter |
|
1384 | aaae9bc0 | Guido Trotter | """
|
1385 | aaae9bc0 | Guido Trotter | # Support passing in a single resource to remove rather than many
|
1386 | aaae9bc0 | Guido Trotter | if isinstance(names, basestring): |
1387 | aaae9bc0 | Guido Trotter | names = [names] |
1388 | aaae9bc0 | Guido Trotter | |
1389 | aaae9bc0 | Guido Trotter | # If we own any subset of this lock it must be a superset of what we want
|
1390 | aaae9bc0 | Guido Trotter | # to delete. The ownership must also be exclusive, but that will be checked
|
1391 | aaae9bc0 | Guido Trotter | # by the lock itself.
|
1392 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned() or self.list_owned().issuperset(names), ( |
1393 | 7f93570a | Iustin Pop | "remove() on acquired lockset %s while not owning all elements" %
|
1394 | 7f93570a | Iustin Pop | self.name)
|
1395 | aaae9bc0 | Guido Trotter | |
1396 | 3f404fc5 | Guido Trotter | removed = [] |
1397 | aaae9bc0 | Guido Trotter | |
1398 | aaae9bc0 | Guido Trotter | for lname in names: |
1399 | aaae9bc0 | Guido Trotter | # Calling delete() acquires the lock exclusively if we don't already own
|
1400 | aaae9bc0 | Guido Trotter | # it, and causes all pending and subsequent lock acquires to fail. It's
|
1401 | aaae9bc0 | Guido Trotter | # fine to call it out of order because delete() also implies release(),
|
1402 | aaae9bc0 | Guido Trotter | # and the assertion above guarantees that if we either already hold
|
1403 | aaae9bc0 | Guido Trotter | # everything we want to delete, or we hold none.
|
1404 | aaae9bc0 | Guido Trotter | try:
|
1405 | aaae9bc0 | Guido Trotter | self.__lockdict[lname].delete()
|
1406 | 3f404fc5 | Guido Trotter | removed.append(lname) |
1407 | aaae9bc0 | Guido Trotter | except (KeyError, errors.LockError): |
1408 | aaae9bc0 | Guido Trotter | # This cannot happen if we were already holding it, verify:
|
1409 | ee2b99e3 | Michael Hanselmann | assert not self.is_owned(), ("remove failed while holding lockset %s" % |
1410 | ee2b99e3 | Michael Hanselmann | self.name)
|
1411 | aaae9bc0 | Guido Trotter | else:
|
1412 | aaae9bc0 | Guido Trotter | # If no LockError was raised we are the ones who deleted the lock.
|
1413 | aaae9bc0 | Guido Trotter | # This means we can safely remove it from lockdict, as any further or
|
1414 | aaae9bc0 | Guido Trotter | # pending delete() or acquire() will fail (and nobody can have the lock
|
1415 | aaae9bc0 | Guido Trotter | # since before our call to delete()).
|
1416 | aaae9bc0 | Guido Trotter | #
|
1417 | aaae9bc0 | Guido Trotter | # This is done in an else clause because if the exception was thrown
|
1418 | aaae9bc0 | Guido Trotter | # it's the job of the one who actually deleted it.
|
1419 | aaae9bc0 | Guido Trotter | del self.__lockdict[lname] |
1420 | aaae9bc0 | Guido Trotter | # And let's remove it from our private list if we owned it.
|
1421 | ee2b99e3 | Michael Hanselmann | if self.is_owned(): |
1422 | b2dabfd6 | Guido Trotter | self._del_owned(name=lname)
|
1423 | aaae9bc0 | Guido Trotter | |
1424 | 3f404fc5 | Guido Trotter | return removed
|
1425 | aaae9bc0 | Guido Trotter | |
1426 | 7ee7c0c7 | Guido Trotter | |
1427 | 7ee7c0c7 | Guido Trotter | # Locking levels, must be acquired in increasing order.
|
1428 | 7ee7c0c7 | Guido Trotter | # Current rules are:
|
1429 | 7ee7c0c7 | Guido Trotter | # - at level LEVEL_CLUSTER resides the Big Ganeti Lock (BGL) which must be
|
1430 | 7ee7c0c7 | Guido Trotter | # acquired before performing any operation, either in shared or in exclusive
|
1431 | 7ee7c0c7 | Guido Trotter | # mode. acquiring the BGL in exclusive mode is discouraged and should be
|
1432 | 7ee7c0c7 | Guido Trotter | # avoided.
|
1433 | 7ee7c0c7 | Guido Trotter | # - at levels LEVEL_NODE and LEVEL_INSTANCE reside node and instance locks.
|
1434 | 7ee7c0c7 | Guido Trotter | # If you need more than one node, or more than one instance, acquire them at
|
1435 | 7ee7c0c7 | Guido Trotter | # the same time.
|
1436 | 7ee7c0c7 | Guido Trotter | LEVEL_CLUSTER = 0
|
1437 | 04e1bfaf | Guido Trotter | LEVEL_INSTANCE = 1
|
1438 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP = 2
|
1439 | 819ca990 | Guido Trotter | LEVEL_NODE = 3
|
1440 | 4e070776 | Michael Hanselmann | LEVEL_NODE_RES = 4
|
1441 | 7ee7c0c7 | Guido Trotter | |
1442 | 4e070776 | Michael Hanselmann | LEVELS = [ |
1443 | 4e070776 | Michael Hanselmann | LEVEL_CLUSTER, |
1444 | 4e070776 | Michael Hanselmann | LEVEL_INSTANCE, |
1445 | 4e070776 | Michael Hanselmann | LEVEL_NODEGROUP, |
1446 | 4e070776 | Michael Hanselmann | LEVEL_NODE, |
1447 | 4e070776 | Michael Hanselmann | LEVEL_NODE_RES, |
1448 | 4e070776 | Michael Hanselmann | ] |
1449 | 7ee7c0c7 | Guido Trotter | |
1450 | 7ee7c0c7 | Guido Trotter | # Lock levels which are modifiable
|
1451 | 4e070776 | Michael Hanselmann | LEVELS_MOD = frozenset([
|
1452 | 4e070776 | Michael Hanselmann | LEVEL_NODE_RES, |
1453 | 4e070776 | Michael Hanselmann | LEVEL_NODE, |
1454 | 4e070776 | Michael Hanselmann | LEVEL_NODEGROUP, |
1455 | 4e070776 | Michael Hanselmann | LEVEL_INSTANCE, |
1456 | 4e070776 | Michael Hanselmann | ]) |
1457 | 7ee7c0c7 | Guido Trotter | |
1458 | 5d7a899e | Michael Hanselmann | #: Lock level names (make sure to use singular form)
|
1459 | ea205dbc | Michael Hanselmann | LEVEL_NAMES = { |
1460 | ea205dbc | Michael Hanselmann | LEVEL_CLUSTER: "cluster",
|
1461 | ea205dbc | Michael Hanselmann | LEVEL_INSTANCE: "instance",
|
1462 | 819ca990 | Guido Trotter | LEVEL_NODEGROUP: "nodegroup",
|
1463 | ea205dbc | Michael Hanselmann | LEVEL_NODE: "node",
|
1464 | 5d7a899e | Michael Hanselmann | LEVEL_NODE_RES: "node-res",
|
1465 | ea205dbc | Michael Hanselmann | } |
1466 | ea205dbc | Michael Hanselmann | |
1467 | 08a6c581 | Guido Trotter | # Constant for the big ganeti lock
|
1468 | 3ccb3a64 | Michael Hanselmann | BGL = "BGL"
|
1469 | 7ee7c0c7 | Guido Trotter | |
1470 | 7ee7c0c7 | Guido Trotter | |
1471 | 7ee7c0c7 | Guido Trotter | class GanetiLockManager: |
1472 | 7ee7c0c7 | Guido Trotter | """The Ganeti Locking Library
|
1473 | 7ee7c0c7 | Guido Trotter |
|
1474 | 5bbd3f7f | Michael Hanselmann | The purpose of this small library is to manage locking for ganeti clusters
|
1475 | 7ee7c0c7 | Guido Trotter | in a central place, while at the same time doing dynamic checks against
|
1476 | 7ee7c0c7 | Guido Trotter | possible deadlocks. It will also make it easier to transition to a different
|
1477 | 7ee7c0c7 | Guido Trotter | lock type should we migrate away from python threads.
|
1478 | 7ee7c0c7 | Guido Trotter |
|
1479 | 7ee7c0c7 | Guido Trotter | """
|
1480 | 7ee7c0c7 | Guido Trotter | _instance = None
|
1481 | 7ee7c0c7 | Guido Trotter | |
1482 | 819ca990 | Guido Trotter | def __init__(self, nodes, nodegroups, instances): |
1483 | 7ee7c0c7 | Guido Trotter | """Constructs a new GanetiLockManager object.
|
1484 | 7ee7c0c7 | Guido Trotter |
|
1485 | 4e07ec8c | Guido Trotter | There should be only a GanetiLockManager object at any time, so this
|
1486 | 4e07ec8c | Guido Trotter | function raises an error if this is not the case.
|
1487 | 7ee7c0c7 | Guido Trotter |
|
1488 | c41eea6e | Iustin Pop | @param nodes: list of node names
|
1489 | 819ca990 | Guido Trotter | @param nodegroups: list of nodegroup uuids
|
1490 | c41eea6e | Iustin Pop | @param instances: list of instance names
|
1491 | 7ee7c0c7 | Guido Trotter |
|
1492 | 7ee7c0c7 | Guido Trotter | """
|
1493 | c41eea6e | Iustin Pop | assert self.__class__._instance is None, \ |
1494 | c41eea6e | Iustin Pop | "double GanetiLockManager instance"
|
1495 | c41eea6e | Iustin Pop | |
1496 | 7ee7c0c7 | Guido Trotter | self.__class__._instance = self |
1497 | 7ee7c0c7 | Guido Trotter | |
1498 | 19b9ba9a | Michael Hanselmann | self._monitor = LockMonitor()
|
1499 | 19b9ba9a | Michael Hanselmann | |
1500 | 7ee7c0c7 | Guido Trotter | # The keyring contains all the locks, at their level and in the correct
|
1501 | 7ee7c0c7 | Guido Trotter | # locking order.
|
1502 | 7ee7c0c7 | Guido Trotter | self.__keyring = {
|
1503 | 5d7a899e | Michael Hanselmann | LEVEL_CLUSTER: LockSet([BGL], "cluster", monitor=self._monitor), |
1504 | 5d7a899e | Michael Hanselmann | LEVEL_NODE: LockSet(nodes, "node", monitor=self._monitor), |
1505 | 5d7a899e | Michael Hanselmann | LEVEL_NODE_RES: LockSet(nodes, "node-res", monitor=self._monitor), |
1506 | 5d7a899e | Michael Hanselmann | LEVEL_NODEGROUP: LockSet(nodegroups, "nodegroup", monitor=self._monitor), |
1507 | 5d7a899e | Michael Hanselmann | LEVEL_INSTANCE: LockSet(instances, "instance",
|
1508 | 19b9ba9a | Michael Hanselmann | monitor=self._monitor),
|
1509 | 19b9ba9a | Michael Hanselmann | } |
1510 | 19b9ba9a | Michael Hanselmann | |
1511 | 5d7a899e | Michael Hanselmann | assert compat.all(ls.name == LEVEL_NAMES[level]
|
1512 | 5d7a899e | Michael Hanselmann | for (level, ls) in self.__keyring.items()) |
1513 | 5d7a899e | Michael Hanselmann | |
1514 | 4c03b2b5 | Michael Hanselmann | def AddToLockMonitor(self, provider): |
1515 | 4c03b2b5 | Michael Hanselmann | """Registers a new lock with the monitor.
|
1516 | 4c03b2b5 | Michael Hanselmann |
|
1517 | 4c03b2b5 | Michael Hanselmann | See L{LockMonitor.RegisterLock}.
|
1518 | 4c03b2b5 | Michael Hanselmann |
|
1519 | 4c03b2b5 | Michael Hanselmann | """
|
1520 | 4c03b2b5 | Michael Hanselmann | return self._monitor.RegisterLock(provider) |
1521 | 4c03b2b5 | Michael Hanselmann | |
1522 | 24d16f76 | Michael Hanselmann | def QueryLocks(self, fields): |
1523 | 19b9ba9a | Michael Hanselmann | """Queries information from all locks.
|
1524 | 19b9ba9a | Michael Hanselmann |
|
1525 | 19b9ba9a | Michael Hanselmann | See L{LockMonitor.QueryLocks}.
|
1526 | 19b9ba9a | Michael Hanselmann |
|
1527 | 19b9ba9a | Michael Hanselmann | """
|
1528 | 24d16f76 | Michael Hanselmann | return self._monitor.QueryLocks(fields) |
1529 | 24d16f76 | Michael Hanselmann | |
1530 | 24d16f76 | Michael Hanselmann | def OldStyleQueryLocks(self, fields): |
1531 | 24d16f76 | Michael Hanselmann | """Queries information from all locks, returning old-style data.
|
1532 | 24d16f76 | Michael Hanselmann |
|
1533 | 24d16f76 | Michael Hanselmann | See L{LockMonitor.OldStyleQueryLocks}.
|
1534 | 24d16f76 | Michael Hanselmann |
|
1535 | 24d16f76 | Michael Hanselmann | """
|
1536 | 24d16f76 | Michael Hanselmann | return self._monitor.OldStyleQueryLocks(fields) |
1537 | 7ee7c0c7 | Guido Trotter | |
1538 | 7ee7c0c7 | Guido Trotter | def _names(self, level): |
1539 | 7ee7c0c7 | Guido Trotter | """List the lock names at the given level.
|
1540 | 7ee7c0c7 | Guido Trotter |
|
1541 | c41eea6e | Iustin Pop | This can be used for debugging/testing purposes.
|
1542 | c41eea6e | Iustin Pop |
|
1543 | c41eea6e | Iustin Pop | @param level: the level whose list of locks to get
|
1544 | 7ee7c0c7 | Guido Trotter |
|
1545 | 7ee7c0c7 | Guido Trotter | """
|
1546 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1547 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level]._names() |
1548 | 7ee7c0c7 | Guido Trotter | |
1549 | ee2b99e3 | Michael Hanselmann | def is_owned(self, level): |
1550 | 7ee7c0c7 | Guido Trotter | """Check whether we are owning locks at the given level
|
1551 | 7ee7c0c7 | Guido Trotter |
|
1552 | 7ee7c0c7 | Guido Trotter | """
|
1553 | ee2b99e3 | Michael Hanselmann | return self.__keyring[level].is_owned() |
1554 | 7ee7c0c7 | Guido Trotter | |
1555 | ee2b99e3 | Michael Hanselmann | def list_owned(self, level): |
1556 | 7ee7c0c7 | Guido Trotter | """Get the set of owned locks at the given level
|
1557 | 7ee7c0c7 | Guido Trotter |
|
1558 | 7ee7c0c7 | Guido Trotter | """
|
1559 | ee2b99e3 | Michael Hanselmann | return self.__keyring[level].list_owned() |
1560 | 07cba1bc | Michael Hanselmann | |
1561 | c6a622cf | Michael Hanselmann | def check_owned(self, level, names, shared=-1): |
1562 | c6a622cf | Michael Hanselmann | """Check if locks at a certain level are owned in a specific mode.
|
1563 | c6a622cf | Michael Hanselmann |
|
1564 | c6a622cf | Michael Hanselmann | @see: L{LockSet.check_owned}
|
1565 | c6a622cf | Michael Hanselmann |
|
1566 | c6a622cf | Michael Hanselmann | """
|
1567 | c6a622cf | Michael Hanselmann | return self.__keyring[level].check_owned(names, shared=shared) |
1568 | c6a622cf | Michael Hanselmann | |
1569 | 7ee7c0c7 | Guido Trotter | def _upper_owned(self, level): |
1570 | 7ee7c0c7 | Guido Trotter | """Check that we don't own any lock at a level greater than the given one.
|
1571 | 7ee7c0c7 | Guido Trotter |
|
1572 | 7ee7c0c7 | Guido Trotter | """
|
1573 | 7ee7c0c7 | Guido Trotter | # This way of checking only works if LEVELS[i] = i, which we check for in
|
1574 | 7ee7c0c7 | Guido Trotter | # the test cases.
|
1575 | ee2b99e3 | Michael Hanselmann | return compat.any((self.is_owned(l) for l in LEVELS[level + 1:])) |
1576 | 7ee7c0c7 | Guido Trotter | |
1577 | b459a848 | Andrea Spadaccini | def _BGL_owned(self): # pylint: disable=C0103 |
1578 | 7ee7c0c7 | Guido Trotter | """Check if the current thread owns the BGL.
|
1579 | 7ee7c0c7 | Guido Trotter |
|
1580 | 7ee7c0c7 | Guido Trotter | Both an exclusive or a shared acquisition work.
|
1581 | 7ee7c0c7 | Guido Trotter |
|
1582 | 7ee7c0c7 | Guido Trotter | """
|
1583 | ee2b99e3 | Michael Hanselmann | return BGL in self.__keyring[LEVEL_CLUSTER].list_owned() |
1584 | 7ee7c0c7 | Guido Trotter | |
1585 | c70d2d9b | Iustin Pop | @staticmethod
|
1586 | b459a848 | Andrea Spadaccini | def _contains_BGL(level, names): # pylint: disable=C0103 |
1587 | c41eea6e | Iustin Pop | """Check if the level contains the BGL.
|
1588 | c41eea6e | Iustin Pop |
|
1589 | c41eea6e | Iustin Pop | Check if acting on the given level and set of names will change
|
1590 | c41eea6e | Iustin Pop | the status of the Big Ganeti Lock.
|
1591 | 7ee7c0c7 | Guido Trotter |
|
1592 | 7ee7c0c7 | Guido Trotter | """
|
1593 | 7ee7c0c7 | Guido Trotter | return level == LEVEL_CLUSTER and (names is None or BGL in names) |
1594 | 7ee7c0c7 | Guido Trotter | |
1595 | b30d95b6 | Michael Hanselmann | def acquire(self, level, names, timeout=None, shared=0, priority=None): |
1596 | 7ee7c0c7 | Guido Trotter | """Acquire a set of resource locks, at the same level.
|
1597 | 7ee7c0c7 | Guido Trotter |
|
1598 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS
|
1599 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be acquired
|
1600 | ec44d893 | Guido Trotter | @type names: list of strings (or string)
|
1601 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be acquired
|
1602 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1603 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1604 | c41eea6e | Iustin Pop | @param shared: whether to acquire in shared mode; by default
|
1605 | c41eea6e | Iustin Pop | an exclusive lock will be acquired
|
1606 | 5e0a6daf | Michael Hanselmann | @type timeout: float
|
1607 | 5e0a6daf | Michael Hanselmann | @param timeout: Maximum time to acquire all locks
|
1608 | b30d95b6 | Michael Hanselmann | @type priority: integer
|
1609 | b30d95b6 | Michael Hanselmann | @param priority: Priority for acquiring lock
|
1610 | 7ee7c0c7 | Guido Trotter |
|
1611 | 7ee7c0c7 | Guido Trotter | """
|
1612 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1613 | 7ee7c0c7 | Guido Trotter | |
1614 | 7ee7c0c7 | Guido Trotter | # Check that we are either acquiring the Big Ganeti Lock or we already own
|
1615 | 7ee7c0c7 | Guido Trotter | # it. Some "legacy" opcodes need to be sure they are run non-concurrently
|
1616 | 7ee7c0c7 | Guido Trotter | # so even if we've migrated we need to at least share the BGL to be
|
1617 | 7ee7c0c7 | Guido Trotter | # compatible with them. Of course if we own the BGL exclusively there's no
|
1618 | 7ee7c0c7 | Guido Trotter | # point in acquiring any other lock, unless perhaps we are half way through
|
1619 | 7ee7c0c7 | Guido Trotter | # the migration of the current opcode.
|
1620 | 7ee7c0c7 | Guido Trotter | assert (self._contains_BGL(level, names) or self._BGL_owned()), ( |
1621 | 7ee7c0c7 | Guido Trotter | "You must own the Big Ganeti Lock before acquiring any other")
|
1622 | 7ee7c0c7 | Guido Trotter | |
1623 | 7ee7c0c7 | Guido Trotter | # Check we don't own locks at the same or upper levels.
|
1624 | 21a6c826 | Guido Trotter | assert not self._upper_owned(level), ("Cannot acquire locks at a level" |
1625 | 7ee7c0c7 | Guido Trotter | " while owning some at a greater one")
|
1626 | 7ee7c0c7 | Guido Trotter | |
1627 | 7ee7c0c7 | Guido Trotter | # Acquire the locks in the set.
|
1628 | b30d95b6 | Michael Hanselmann | return self.__keyring[level].acquire(names, shared=shared, timeout=timeout, |
1629 | b30d95b6 | Michael Hanselmann | priority=priority) |
1630 | 7ee7c0c7 | Guido Trotter | |
1631 | 3dbe3ddf | Michael Hanselmann | def downgrade(self, level, names=None): |
1632 | 3dbe3ddf | Michael Hanselmann | """Downgrade a set of resource locks from exclusive to shared mode.
|
1633 | 3dbe3ddf | Michael Hanselmann |
|
1634 | 3dbe3ddf | Michael Hanselmann | You must have acquired the locks in exclusive mode.
|
1635 | 3dbe3ddf | Michael Hanselmann |
|
1636 | 3dbe3ddf | Michael Hanselmann | @type level: member of locking.LEVELS
|
1637 | 3dbe3ddf | Michael Hanselmann | @param level: the level at which the locks shall be downgraded
|
1638 | 3dbe3ddf | Michael Hanselmann | @type names: list of strings, or None
|
1639 | 3dbe3ddf | Michael Hanselmann | @param names: the names of the locks which shall be downgraded
|
1640 | 3dbe3ddf | Michael Hanselmann | (defaults to all the locks acquired at the level)
|
1641 | 3dbe3ddf | Michael Hanselmann |
|
1642 | 3dbe3ddf | Michael Hanselmann | """
|
1643 | 3dbe3ddf | Michael Hanselmann | assert level in LEVELS, "Invalid locking level %s" % level |
1644 | 3dbe3ddf | Michael Hanselmann | |
1645 | 3dbe3ddf | Michael Hanselmann | return self.__keyring[level].downgrade(names=names) |
1646 | 3dbe3ddf | Michael Hanselmann | |
1647 | 7ee7c0c7 | Guido Trotter | def release(self, level, names=None): |
1648 | 7ee7c0c7 | Guido Trotter | """Release a set of resource locks, at the same level.
|
1649 | 7ee7c0c7 | Guido Trotter |
|
1650 | c41eea6e | Iustin Pop | You must have acquired the locks, either in shared or in exclusive
|
1651 | c41eea6e | Iustin Pop | mode, before releasing them.
|
1652 | 7ee7c0c7 | Guido Trotter |
|
1653 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS
|
1654 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be released
|
1655 | ec44d893 | Guido Trotter | @type names: list of strings, or None
|
1656 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be released
|
1657 | c41eea6e | Iustin Pop | (defaults to all the locks acquired at that level)
|
1658 | 7ee7c0c7 | Guido Trotter |
|
1659 | 7ee7c0c7 | Guido Trotter | """
|
1660 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS, "Invalid locking level %s" % level |
1661 | 7ee7c0c7 | Guido Trotter | assert (not self._contains_BGL(level, names) or |
1662 | 7ee7c0c7 | Guido Trotter | not self._upper_owned(LEVEL_CLUSTER)), ( |
1663 | 7ee7c0c7 | Guido Trotter | "Cannot release the Big Ganeti Lock while holding something"
|
1664 | e4335b5b | Michael Hanselmann | " at upper levels (%r)" %
|
1665 | ee2b99e3 | Michael Hanselmann | (utils.CommaJoin(["%s=%r" % (LEVEL_NAMES[i], self.list_owned(i)) |
1666 | 1f864b60 | Iustin Pop | for i in self.__keyring.keys()]), )) |
1667 | 7ee7c0c7 | Guido Trotter | |
1668 | 7ee7c0c7 | Guido Trotter | # Release will complain if we don't own the locks already
|
1669 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level].release(names) |
1670 | 7ee7c0c7 | Guido Trotter | |
1671 | 7ee7c0c7 | Guido Trotter | def add(self, level, names, acquired=0, shared=0): |
1672 | 7ee7c0c7 | Guido Trotter | """Add locks at the specified level.
|
1673 | 7ee7c0c7 | Guido Trotter |
|
1674 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS_MOD
|
1675 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be added
|
1676 | ec44d893 | Guido Trotter | @type names: list of strings
|
1677 | c41eea6e | Iustin Pop | @param names: names of the locks to acquire
|
1678 | ec44d893 | Guido Trotter | @type acquired: integer (0/1) used as a boolean
|
1679 | c41eea6e | Iustin Pop | @param acquired: whether to acquire the newly added locks
|
1680 | ec44d893 | Guido Trotter | @type shared: integer (0/1) used as a boolean
|
1681 | c41eea6e | Iustin Pop | @param shared: whether the acquisition will be shared
|
1682 | c41eea6e | Iustin Pop |
|
1683 | 7ee7c0c7 | Guido Trotter | """
|
1684 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS_MOD, "Invalid or immutable level %s" % level |
1685 | 7ee7c0c7 | Guido Trotter | assert self._BGL_owned(), ("You must own the BGL before performing other" |
1686 | 7ee7c0c7 | Guido Trotter | " operations")
|
1687 | 7ee7c0c7 | Guido Trotter | assert not self._upper_owned(level), ("Cannot add locks at a level" |
1688 | 7ee7c0c7 | Guido Trotter | " while owning some at a greater one")
|
1689 | 7ee7c0c7 | Guido Trotter | return self.__keyring[level].add(names, acquired=acquired, shared=shared) |
1690 | 7ee7c0c7 | Guido Trotter | |
1691 | 5e0a6daf | Michael Hanselmann | def remove(self, level, names): |
1692 | 7ee7c0c7 | Guido Trotter | """Remove locks from the specified level.
|
1693 | 7ee7c0c7 | Guido Trotter |
|
1694 | c41eea6e | Iustin Pop | You must either already own the locks you are trying to remove
|
1695 | c41eea6e | Iustin Pop | exclusively or not own any lock at an upper level.
|
1696 | 7ee7c0c7 | Guido Trotter |
|
1697 | ec44d893 | Guido Trotter | @type level: member of locking.LEVELS_MOD
|
1698 | ec44d893 | Guido Trotter | @param level: the level at which the locks shall be removed
|
1699 | ec44d893 | Guido Trotter | @type names: list of strings
|
1700 | c41eea6e | Iustin Pop | @param names: the names of the locks which shall be removed
|
1701 | c41eea6e | Iustin Pop | (special lock names, or instance/node names)
|
1702 | 7ee7c0c7 | Guido Trotter |
|
1703 | 7ee7c0c7 | Guido Trotter | """
|
1704 | 7ee7c0c7 | Guido Trotter | assert level in LEVELS_MOD, "Invalid or immutable level %s" % level |
1705 | 7ee7c0c7 | Guido Trotter | assert self._BGL_owned(), ("You must own the BGL before performing other" |
1706 | 7ee7c0c7 | Guido Trotter | " operations")
|
1707 | f12eadb3 | Iustin Pop | # Check we either own the level or don't own anything from here
|
1708 | f12eadb3 | Iustin Pop | # up. LockSet.remove() will check the case in which we don't own
|
1709 | f12eadb3 | Iustin Pop | # all the needed resources, or we have a shared ownership.
|
1710 | ee2b99e3 | Michael Hanselmann | assert self.is_owned(level) or not self._upper_owned(level), ( |
1711 | 7ee7c0c7 | Guido Trotter | "Cannot remove locks at a level while not owning it or"
|
1712 | 7ee7c0c7 | Guido Trotter | " owning some at a greater one")
|
1713 | 5e0a6daf | Michael Hanselmann | return self.__keyring[level].remove(names) |
1714 | 19b9ba9a | Michael Hanselmann | |
1715 | 19b9ba9a | Michael Hanselmann | |
1716 | 44b4eddc | Michael Hanselmann | def _MonitorSortKey((item, idx, num)): |
1717 | e4e35357 | Michael Hanselmann | """Sorting key function.
|
1718 | e4e35357 | Michael Hanselmann |
|
1719 | 44b4eddc | Michael Hanselmann | Sort by name, registration order and then order of information. This provides
|
1720 | 44b4eddc | Michael Hanselmann | a stable sort order over different providers, even if they return the same
|
1721 | 44b4eddc | Michael Hanselmann | name.
|
1722 | e4e35357 | Michael Hanselmann |
|
1723 | e4e35357 | Michael Hanselmann | """
|
1724 | e4e35357 | Michael Hanselmann | (name, _, _, _) = item |
1725 | e4e35357 | Michael Hanselmann | |
1726 | 44b4eddc | Michael Hanselmann | return (utils.NiceSortKey(name), num, idx)
|
1727 | e4e35357 | Michael Hanselmann | |
1728 | e4e35357 | Michael Hanselmann | |
1729 | 19b9ba9a | Michael Hanselmann | class LockMonitor(object): |
1730 | 19b9ba9a | Michael Hanselmann | _LOCK_ATTR = "_lock"
|
1731 | 19b9ba9a | Michael Hanselmann | |
1732 | 19b9ba9a | Michael Hanselmann | def __init__(self): |
1733 | 19b9ba9a | Michael Hanselmann | """Initializes this class.
|
1734 | 19b9ba9a | Michael Hanselmann |
|
1735 | 19b9ba9a | Michael Hanselmann | """
|
1736 | 19b9ba9a | Michael Hanselmann | self._lock = SharedLock("LockMonitor") |
1737 | 19b9ba9a | Michael Hanselmann | |
1738 | e4e35357 | Michael Hanselmann | # Counter for stable sorting
|
1739 | e4e35357 | Michael Hanselmann | self._counter = itertools.count(0) |
1740 | e4e35357 | Michael Hanselmann | |
1741 | 19b9ba9a | Michael Hanselmann | # Tracked locks. Weak references are used to avoid issues with circular
|
1742 | 19b9ba9a | Michael Hanselmann | # references and deletion.
|
1743 | 19b9ba9a | Michael Hanselmann | self._locks = weakref.WeakKeyDictionary()
|
1744 | 19b9ba9a | Michael Hanselmann | |
1745 | 19b9ba9a | Michael Hanselmann | @ssynchronized(_LOCK_ATTR)
|
1746 | 44b4eddc | Michael Hanselmann | def RegisterLock(self, provider): |
1747 | 19b9ba9a | Michael Hanselmann | """Registers a new lock.
|
1748 | 19b9ba9a | Michael Hanselmann |
|
1749 | 44b4eddc | Michael Hanselmann | @param provider: Object with a callable method named C{GetLockInfo}, taking
|
1750 | 44b4eddc | Michael Hanselmann | a single C{set} containing the requested information items
|
1751 | 44b4eddc | Michael Hanselmann | @note: It would be nicer to only receive the function generating the
|
1752 | 44b4eddc | Michael Hanselmann | requested information but, as it turns out, weak references to bound
|
1753 | 44b4eddc | Michael Hanselmann | methods (e.g. C{self.GetLockInfo}) are tricky; there are several
|
1754 | 44b4eddc | Michael Hanselmann | workarounds, but none of the ones I found works properly in combination
|
1755 | 44b4eddc | Michael Hanselmann | with a standard C{WeakKeyDictionary}
|
1756 | 44b4eddc | Michael Hanselmann |
|
1757 | 19b9ba9a | Michael Hanselmann | """
|
1758 | 44b4eddc | Michael Hanselmann | assert provider not in self._locks, "Duplicate registration" |
1759 | e4e35357 | Michael Hanselmann | |
1760 | e4e35357 | Michael Hanselmann | # There used to be a check for duplicate names here. As it turned out, when
|
1761 | e4e35357 | Michael Hanselmann | # a lock is re-created with the same name in a very short timeframe, the
|
1762 | e4e35357 | Michael Hanselmann | # previous instance might not yet be removed from the weakref dictionary.
|
1763 | e4e35357 | Michael Hanselmann | # By keeping track of the order of incoming registrations, a stable sort
|
1764 | e4e35357 | Michael Hanselmann | # ordering can still be guaranteed.
|
1765 | e4e35357 | Michael Hanselmann | |
1766 | 44b4eddc | Michael Hanselmann | self._locks[provider] = self._counter.next() |
1767 | 19b9ba9a | Michael Hanselmann | |
1768 | 24d16f76 | Michael Hanselmann | def _GetLockInfo(self, requested): |
1769 | 44b4eddc | Michael Hanselmann | """Get information from all locks.
|
1770 | 19b9ba9a | Michael Hanselmann |
|
1771 | 19b9ba9a | Michael Hanselmann | """
|
1772 | 44b4eddc | Michael Hanselmann | # Must hold lock while getting consistent list of tracked items
|
1773 | 44b4eddc | Michael Hanselmann | self._lock.acquire(shared=1) |
1774 | 44b4eddc | Michael Hanselmann | try:
|
1775 | 44b4eddc | Michael Hanselmann | items = self._locks.items()
|
1776 | 44b4eddc | Michael Hanselmann | finally:
|
1777 | 44b4eddc | Michael Hanselmann | self._lock.release()
|
1778 | 44b4eddc | Michael Hanselmann | |
1779 | 44b4eddc | Michael Hanselmann | return [(info, idx, num)
|
1780 | 44b4eddc | Michael Hanselmann | for (provider, num) in items |
1781 | 44b4eddc | Michael Hanselmann | for (idx, info) in enumerate(provider.GetLockInfo(requested))] |
1782 | 19b9ba9a | Michael Hanselmann | |
1783 | 24d16f76 | Michael Hanselmann | def _Query(self, fields): |
1784 | 24d16f76 | Michael Hanselmann | """Queries information from all locks.
|
1785 | 19b9ba9a | Michael Hanselmann |
|
1786 | 24d16f76 | Michael Hanselmann | @type fields: list of strings
|
1787 | 24d16f76 | Michael Hanselmann | @param fields: List of fields to return
|
1788 | 24d16f76 | Michael Hanselmann |
|
1789 | 24d16f76 | Michael Hanselmann | """
|
1790 | 24d16f76 | Michael Hanselmann | qobj = query.Query(query.LOCK_FIELDS, fields) |
1791 | 24d16f76 | Michael Hanselmann | |
1792 | e4e35357 | Michael Hanselmann | # Get all data with internal lock held and then sort by name and incoming
|
1793 | e4e35357 | Michael Hanselmann | # order
|
1794 | e4e35357 | Michael Hanselmann | lockinfo = sorted(self._GetLockInfo(qobj.RequestedData()), |
1795 | e4e35357 | Michael Hanselmann | key=_MonitorSortKey) |
1796 | 24d16f76 | Michael Hanselmann | |
1797 | e4e35357 | Michael Hanselmann | # Extract lock information and build query data
|
1798 | eb62069e | Iustin Pop | return (qobj, query.LockQueryData(map(compat.fst, lockinfo))) |
1799 | 19b9ba9a | Michael Hanselmann | |
1800 | 24d16f76 | Michael Hanselmann | def QueryLocks(self, fields): |
1801 | 19b9ba9a | Michael Hanselmann | """Queries information from all locks.
|
1802 | 19b9ba9a | Michael Hanselmann |
|
1803 | 19b9ba9a | Michael Hanselmann | @type fields: list of strings
|
1804 | 19b9ba9a | Michael Hanselmann | @param fields: List of fields to return
|
1805 | 19b9ba9a | Michael Hanselmann |
|
1806 | 19b9ba9a | Michael Hanselmann | """
|
1807 | 24d16f76 | Michael Hanselmann | (qobj, ctx) = self._Query(fields)
|
1808 | 19b9ba9a | Michael Hanselmann | |
1809 | 24d16f76 | Michael Hanselmann | # Prepare query response
|
1810 | 24d16f76 | Michael Hanselmann | return query.GetQueryResponse(qobj, ctx)
|
1811 | 24d16f76 | Michael Hanselmann | |
1812 | 24d16f76 | Michael Hanselmann | def OldStyleQueryLocks(self, fields): |
1813 | 24d16f76 | Michael Hanselmann | """Queries information from all locks, returning old-style data.
|
1814 | 24d16f76 | Michael Hanselmann |
|
1815 | 24d16f76 | Michael Hanselmann | @type fields: list of strings
|
1816 | 24d16f76 | Michael Hanselmann | @param fields: List of fields to return
|
1817 | 24d16f76 | Michael Hanselmann |
|
1818 | 24d16f76 | Michael Hanselmann | """
|
1819 | 24d16f76 | Michael Hanselmann | (qobj, ctx) = self._Query(fields)
|
1820 | 19b9ba9a | Michael Hanselmann | |
1821 | 24d16f76 | Michael Hanselmann | return qobj.OldStyleQuery(ctx) |