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Python 2.6 one, since the intention is to keep an unified 2.x/3.x codebase. The Python code is automatically translated using "2to3". Please, do not update this code in Python 3.0 by hand. Update the 2.6 one and then do "2to3".
83 lines
2.9 KiB
Python
83 lines
2.9 KiB
Python
#------------------------------------------------------------------------
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#
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# Copyright (C) 2000 Autonomous Zone Industries
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#
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# License: This is free software. You may use this software for any
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# purpose including modification/redistribution, so long as
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# this header remains intact and that you do not claim any
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# rights of ownership or authorship of this software. This
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# software has been tested, but no warranty is expressed or
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# implied.
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#
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# Author: Gregory P. Smith <greg@krypto.org>
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#
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# Note: I don't know how useful this is in reality since when a
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# DBLockDeadlockError happens the current transaction is supposed to be
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# aborted. If it doesn't then when the operation is attempted again
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# the deadlock is still happening...
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# --Robin
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#
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#------------------------------------------------------------------------
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#
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# import the time.sleep function in a namespace safe way to allow
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# "from bsddb.dbutils import *"
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#
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from time import sleep as _sleep
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import sys
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absolute_import = (sys.version_info[0] >= 3)
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if absolute_import :
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# Because this syntaxis is not valid before Python 2.5
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exec("from . import db")
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else :
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from . import db
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# always sleep at least N seconds between retrys
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_deadlock_MinSleepTime = 1.0/128
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# never sleep more than N seconds between retrys
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_deadlock_MaxSleepTime = 3.14159
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# Assign a file object to this for a "sleeping" message to be written to it
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# each retry
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_deadlock_VerboseFile = None
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def DeadlockWrap(function, *_args, **_kwargs):
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"""DeadlockWrap(function, *_args, **_kwargs) - automatically retries
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function in case of a database deadlock.
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This is a function intended to be used to wrap database calls such
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that they perform retrys with exponentially backing off sleeps in
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between when a DBLockDeadlockError exception is raised.
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A 'max_retries' parameter may optionally be passed to prevent it
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from retrying forever (in which case the exception will be reraised).
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d = DB(...)
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d.open(...)
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DeadlockWrap(d.put, "foo", data="bar") # set key "foo" to "bar"
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"""
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sleeptime = _deadlock_MinSleepTime
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max_retries = _kwargs.get('max_retries', -1)
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if 'max_retries' in _kwargs:
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del _kwargs['max_retries']
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while True:
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try:
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return function(*_args, **_kwargs)
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except db.DBLockDeadlockError:
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if _deadlock_VerboseFile:
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_deadlock_VerboseFile.write(
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'dbutils.DeadlockWrap: sleeping %1.3f\n' % sleeptime)
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_sleep(sleeptime)
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# exponential backoff in the sleep time
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sleeptime *= 2
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if sleeptime > _deadlock_MaxSleepTime:
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sleeptime = _deadlock_MaxSleepTime
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max_retries -= 1
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if max_retries == -1:
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raise
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#------------------------------------------------------------------------
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