/usr/share/pyshared/transaction/_manager.py is in python-transaction 1.1.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 | ############################################################################
#
# Copyright (c) 2004 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
############################################################################
"""A TransactionManager controls transaction boundaries.
It coordinates application code and resource managers, so that they
are associated with the right transaction.
"""
from transaction.weakset import WeakSet
from transaction._transaction import Transaction
from transaction.interfaces import TransientError
import threading
# We have to remember sets of synch objects, especially Connections.
# But we don't want mere registration with a transaction manager to
# keep a synch object alive forever; in particular, it's common
# practice not to explicitly close Connection objects, and keeping
# a Connection alive keeps a potentially huge number of other objects
# alive (e.g., the cache, and everything reachable from it too).
# Therefore we use "weak sets" internally.
# Call the ISynchronizer newTransaction() method on every element of
# WeakSet synchs.
# A transaction manager needs to do this whenever begin() is called.
# Since it would be good if tm.get() returned the new transaction while
# newTransaction() is running, calling this has to be delayed until after
# the transaction manager has done whatever it needs to do to make its
# get() return the new txn.
def _new_transaction(txn, synchs):
if synchs:
synchs.map(lambda s: s.newTransaction(txn))
# Important: we must always pass a WeakSet (even if empty) to the Transaction
# constructor: synchronizers are registered with the TM, but the
# ISynchronizer xyzCompletion() methods are called by Transactions without
# consulting the TM, so we need to pass a mutable collection of synchronizers
# so that Transactions "see" synchronizers that get registered after the
# Transaction object is constructed.
class TransactionManager(object):
def __init__(self):
self._txn = None
self._synchs = WeakSet()
def begin(self):
if self._txn is not None:
self._txn.abort()
txn = self._txn = Transaction(self._synchs, self)
_new_transaction(txn, self._synchs)
return txn
__enter__ = lambda self: self.begin()
def get(self):
if self._txn is None:
self._txn = Transaction(self._synchs, self)
return self._txn
def free(self, txn):
assert txn is self._txn
self._txn = None
def registerSynch(self, synch):
self._synchs.add(synch)
def unregisterSynch(self, synch):
self._synchs.remove(synch)
def isDoomed(self):
return self.get().isDoomed()
def doom(self):
return self.get().doom()
def commit(self):
return self.get().commit()
def abort(self):
return self.get().abort()
def __exit__(self, t, v, tb):
if v is None:
self.commit()
else:
self.abort()
def savepoint(self, optimistic=False):
return self.get().savepoint(optimistic)
def attempts(self, number=3):
assert number > 0
while number:
number -= 1
if number:
yield Attempt(self)
else:
yield self
def _retryable(self, error_type, error):
if issubclass(error_type, TransientError):
return True
for dm in self.get()._resources:
should_retry = getattr(dm, 'should_retry', None)
if (should_retry is not None) and should_retry(error):
return True
class ThreadTransactionManager(TransactionManager, threading.local):
"""Thread-aware transaction manager.
Each thread is associated with a unique transaction.
"""
class Attempt(object):
def __init__(self, manager):
self.manager = manager
def __enter__(self):
return self.manager.__enter__()
def __exit__(self, t, v, tb):
if v is None:
self.manager.commit()
else:
retry = self.manager._retryable(t, v)
self.manager.abort()
return retry
|