[Zope-Checkins] CVS: Zope3/lib/python/Transaction - Exceptions.py:1.1.2.1 IDataManager.py:1.1.2.1 ITransaction.py:1.1.2.1 __init__.py:1.1.2.1 _defaultTransaction.py:1.1.2.1
Jim Fulton
jim@zope.com
Sun, 25 Nov 2001 19:16:06 -0500
Update of /cvs-repository/Zope3/lib/python/Transaction
In directory cvs.zope.org:/tmp/cvs-serv13352
Added Files:
Tag: Zope-3x-branch
Exceptions.py IDataManager.py ITransaction.py __init__.py
_defaultTransaction.py
Log Message:
Factored transactions into separate package.
=== Added File Zope3/lib/python/Transaction/Exceptions.py ===
##############################################################################
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 1.1 (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.
##############################################################################
class TransactionError(Exception):
"""An error occured due to normal transaction processing
"""
class ConflictError(TransactionError):
"""Two transactions tried to modify the same object at once
This transaction should be resubmitted.
"""
=== Added File Zope3/lib/python/Transaction/IDataManager.py ===
##############################################################################
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 1.1 (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.
##############################################################################
# Hack to overcome absense of Interface package
try:
from Interface import Interface
except ImportError:
class Interface: pass
class IDataManager(Interface):
"""Data management interface for storing objects transactionally
This is currently implemented by ZODB database connections.
"""
# This needs to be filled out. :)
=== Added File Zope3/lib/python/Transaction/ITransaction.py ===
##############################################################################
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 1.1 (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.
##############################################################################
# Hack to overcome absense of Interface package
try:
from Interface import Interface
except ImportError:
class Interface: pass
class ITransaction(Interface):
"""Transaction objects
Application code typically gets these by calling
get_transaction().
"""
def abort(subtransaction=0):
"""Abort the current transaction
If subtransaction is true, then only abort the current subtransaction.
"""
def begin(info=None, subtransaction=0):
"""Begin a transaction
If info is specified, it must be a string and will be used to
initialize the transaction description.
If subtransaction is true, then begin subtransaction.
"""
def commit(subtransaction=0):
"""Commit a transaction
If subtransaction is true, then only abort the current subtransaction.
"""
def register(object):
"""Register the object with the current transaction.
The object may have a '_p_jar' attribute. If it has this
attribute then the attribute value may be 'None', or an object
that implements the IDataManager interface. If the value is
'None', then the object will not affect the current
transaction.
If the object doesn't have a '_p_jar' attribute, then the
object must implement the IDataManager interface itself.
"""
def note(text):
"""Add the text to the transaction description
If there previous description isn't empty, a blank line is
added before the new text.
"""
def setUser(user_name, path="/"):
"""Set the transaction user name.
The user is actually set to the path followed by a space and
the user name.
"""
def setExtendedInfo(name, value):
"""Set extended information
"""
=== Added File Zope3/lib/python/Transaction/__init__.py ===
##############################################################################
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 1.1 (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.
##############################################################################
def get_transaction():
return get_transaction_hook()
from _defaultTransaction import get_transaction as get_transaction_hook
from _defaultTransaction import Transaction
=== Added File Zope3/lib/python/Transaction/_defaultTransaction.py ===
##############################################################################
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 1.1 (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.
##############################################################################
"""Transaction management
$Id: _defaultTransaction.py,v 1.1.2.1 2001/11/26 00:16:06 jim Exp $"""
__version__='$Revision: 1.1.2.1 $'[11:-2]
import time, sys, struct
from struct import pack
from string import split, strip, join
from zLOG import LOG, ERROR, PANIC
from Exceptions import ConflictError, TransactionError
# Flag indicating whether certain errors have occurred.
hosed=0
class Transaction:
'Simple transaction objects for single-threaded applications.'
user=''
description=''
_connections=None
_extension=None
_sub=None # This is a subtrasaction flag
# The _non_st_objects variable is either None or a list
# of jars that do not support subtransactions. This is used to
# manage non-subtransaction-supporting jars during subtransaction
# commits and aborts to ensure that they are correctly committed
# or aborted in the "outside" transaction.
_non_st_objects=None
def __init__(self, id=None):
self._id=id
self._objects=[]
self._append=self._objects.append
def _init(self):
self._objects=[]
self._append=self._objects.append
self.user=self.description=''
if self._connections:
for c in self._connections.values(): c.close()
del self._connections
def sub(self):
# Create a manually managed subtransaction for internal use
r=self.__class__()
r.user=self.user
r.description=self.description
r._extension=self._extension
return r
def __str__(self): return "%.3f\t%s" % (self._id or 0, self.user)
def __del__(self):
if self._objects: self.abort(freeme=0)
def abort(self, subtransaction=0, freeme=1):
'''Abort the transaction.
This is called from the application. This means that we haven\'t
entered two-phase commit yet, so no tpc_ messages are sent.
'''
if subtransaction and (self._non_st_objects is not None):
raise TransactionError, (
"""Attempted to abort a sub-transaction, but a participating
data manager doesn't support partial abort.
""")
t = None
subj = self._sub
subjars = ()
if not subtransaction:
# Must add in any non-subtransaction supporting objects that
# may have been stowed away from previous subtransaction
# commits.
if self._non_st_objects is not None:
self._objects.extend(self._non_st_objects)
self._non_st_objects = None
if subj is not None:
# Abort of top-level transaction after commiting
# subtransactions.
subjars = subj.values()
self._sub = None
try:
# Abort the objects
for o in self._objects:
try:
j = getattr(o, '_p_jar', o)
if j is not None:
j.abort(o, self)
except:
if t is None:
t, v, tb = sys.exc_info()
# Ugh, we need to abort work done in sub-transactions.
while subjars:
j = subjars.pop()
j.abort_sub(self) # This should never fail
if t is not None:
raise t, v, tb
finally:
if t is not None:
del tb # don't keep traceback in local variable
del self._objects[:] # Clear registered
if not subtransaction and freeme:
if self._id is not None:
free_transaction()
else:
self._init()
def begin(self, info=None, subtransaction=None):
'''Begin a new transaction.
This aborts any transaction in progres.
'''
if self._objects: self.abort(subtransaction, 0)
if info:
info=split(info,'\t')
self.user=strip(info[0])
self.description=strip(join(info[1:],'\t'))
def commit(self, subtransaction=None):
'Finalize the transaction'
global hosed
objects=self._objects
jars={}
jarsv = None
subj=self._sub
subjars=()
if subtransaction:
if subj is None: self._sub=subj={}
else:
if subj is not None:
if objects:
# Do an implicit sub-transaction commit:
self.commit(1)
objects=[]
subjars=subj.values()
self._sub=None
# If not a subtransaction, then we need to add any non-
# subtransaction-supporting objects that may have been
# stowed away during subtransaction commits to _objects.
if (subtransaction is None) and (self._non_st_objects is not None):
append=objects.append
for object in self._non_st_objects:
append(object)
self._non_st_objects = None
t=v=tb=None
if (objects or subjars) and hosed:
# Something really bad happened and we don't
# trust the system state.
raise TransactionError, (
"""A serious error, which was probably a system error,
occurred in a previous database transaction. This
application may be in an invalid state and must be
restarted before database updates can be allowed.
Beware though that if the error was due to a serious
system problem, such as a disk full condition, then
the application may not come up until you deal with
the system problem. See your application log for
information on the error that lead to this problem.
""")
try:
# It's important that:
#
# - Every object in self._objects is either committed
# or aborted.
#
# - For each object that is committed
# we call tpc_begin on it's jar at least once
#
# - For every jar for which we've called tpc_begin on,
# we either call tpc_abort or tpc_finish. It is OK
# to call these multiple times, as the storage is
# required to ignore these calls if tpc_begin has not
# been called.
ncommitted=0
try:
for o in objects:
j=getattr(o, '_p_jar', o)
if j is not None:
i=id(j)
if not jars.has_key(i):
jars[i]=j
if subtransaction:
# If a jar does not support subtransactions,
# we need to save it away to be committed in
# the outer transaction.
try: j.tpc_begin(self, subtransaction)
except TypeError:
j.tpc_begin(self)
if hasattr(j, 'commit_sub'):
subj[i]=j
else:
if self._non_st_objects is None:
self._non_st_objects = []
self._non_st_objects.append(o)
continue
else:
j.tpc_begin(self)
j.commit(o,self)
ncommitted=ncommitted+1
# Commit work done in subtransactions
while subjars:
j=subjars.pop()
i=id(j)
if not jars.has_key(i):
jars[i]=j
j.commit_sub(self)
jarsv = jars.values()
for jar in jarsv:
if not subtransaction:
try: jar=jar.tpc_vote
except: pass
else: jar(self) # last chance to bail
try:
# Try to finish one jar, since we may be able to
# recover if the first one fails.
if jarsv:
jarsv[-1].tpc_finish(self) # This should never fail
jarsv.pop() # It didn't, so it's taken care of.
except:
# Bug if it does, we need to keep track of it
LOG('ZODB', ERROR,
"A storage error occurred in the last phase of a "
"two-phase commit. This shouldn\'t happen. ",
error=sys.exc_info())
raise
try:
while jarsv:
jarsv[-1].tpc_finish(self) # This should never fail
jarsv.pop() # It didn't, so it's taken care of.
except:
# Bug if it does, we need to yell FIRE!
# Someone finished, so don't allow any more
# work without at least a restart!
hosed=1
LOG('ZODB', PANIC,
"A storage error occurred in the last phase of a "
"two-phase commit. This shouldn\'t happen. "
"The application may be in a hosed state, so "
"transactions will not be allowed to commit "
"until the site/storage is reset by a restart. ",
error=sys.exc_info())
raise
except:
t,v,tb=sys.exc_info()
# Ugh, we got an got an error during commit, so we
# have to clean up.
# First, we have to abort any uncommitted objects.
for o in objects[ncommitted:]:
try:
j=getattr(o, '_p_jar', o)
if j is not None: j.abort(o, self)
except: pass
# Then, we unwind TPC for the jars that began it.
if jarsv is None:
jarsv = jars.values()
for j in jarsv:
try: j.tpc_abort(self) # This should never fail
except:
LOG('ZODB', ERROR,
"A storage error occured during object abort "
"This shouldn\'t happen. ",
error=sys.exc_info())
# Ugh, we need to abort work done in sub-transactions.
while subjars:
j=subjars.pop()
j.abort_sub(self) # This should never fail
raise t,v,tb
finally:
tb=None
del objects[:] # clear registered
if not subtransaction and self._id is not None: free_transaction()
def register(self,object):
'Register the given object for transaction control.'
self._append(object)
def note(self, text):
if self.description:
self.description = "%s\n\n%s" % (self.description, strip(text))
else:
self.description = strip(text)
def setUser(self, user_name, path='/'):
self.user="%s %s" % (path, user_name)
def setExtendedInfo(self, name, value):
ext=self._extension
if ext is None:
ext=self._extension={}
ext[name]=value
############################################################################
# install get_transaction:
try:
import thread
except:
_t=Transaction(None)
def get_transaction(_t=_t): return _t
def free_transaction(_t=_t): _t.__init__()
else:
_t={}
def get_transaction(_id=thread.get_ident, _t=_t, get=_t.get, None=None):
id=_id()
t=get(id, None)
if t is None: _t[id]=t=Transaction(id)
return t
def free_transaction(_id=thread.get_ident, _t=_t):
id=_id()
try: del _t[id]
except KeyError: pass
del thread
del _t