[Erp5-report] r11669 - /erp5/trunk/products/ERP5Type/Tool/MemcachedTool.py
nobody at svn.erp5.org
nobody at svn.erp5.org
Mon Dec 11 16:34:16 CET 2006
Author: vincent
Date: Mon Dec 11 16:34:14 2006
New Revision: 11669
URL: http://svn.erp5.org?rev=11669&view=rev
Log:
Support multiple memcached servers (not implemented in the web interface yet).
s/dictionnary/dictionary/g
Fix property name begining by _v_ where not needed.
Raise an error if key is not a string.
Raise KeyError in __getattr__ when a None is returned by python-memcached.
Add try/except in _finish to be sure not to raise any error.
Modified:
erp5/trunk/products/ERP5Type/Tool/MemcachedTool.py
Modified: erp5/trunk/products/ERP5Type/Tool/MemcachedTool.py
URL: http://svn.erp5.org/erp5/trunk/products/ERP5Type/Tool/MemcachedTool.py?rev=11669&r1=11668&r2=11669&view=diff
==============================================================================
--- erp5/trunk/products/ERP5Type/Tool/MemcachedTool.py (original)
+++ erp5/trunk/products/ERP5Type/Tool/MemcachedTool.py Mon Dec 11 16:34:14 2006
@@ -34,8 +34,10 @@
if allowMemcachedTool():
import memcache
+ import traceback
from Shared.DC.ZRDB.TM import TM
from Products.PythonScripts.Utility import allow_class
+ from zLOG import LOG
MARKER = tuple()
UPDATE_ACTION = 'update'
@@ -43,7 +45,7 @@
class MemcachedDict(TM):
"""
- Present memcached similarly to a dictionnary (not all method are
+ Present memcached similarly to a dictionary (not all method are
available).
Uses transactions to only update memcached at commit time.
No conflict generation/resolution : last edit wins.
@@ -53,7 +55,7 @@
- make picklable ?
"""
- def __init__(self, server='127.0.0.1:11211'):
+ def __init__(self, server_list=('127.0.0.1:11211', )):
"""
Initialise properties :
memcached_connection
@@ -62,7 +64,7 @@
Dictionnary used as a connection cache with duration limited to
transaction length.
scheduled_action_dict
- Each key in this dictionnary must be handled at transaction commit.
+ Each key in this dictionary must be handled at transaction commit.
Value gives the action to take :
UPDATE_ACTION
Take value from local cache and send it to memcached.
@@ -71,7 +73,7 @@
"""
self.local_cache = {}
self.scheduled_action_dict = {}
- self.memcached_connection = memcache.Client((server, ))
+ self.memcached_connection = memcache.Client(server_list)
def __del__(self):
"""
@@ -86,11 +88,14 @@
Invalidate all local cache to make sure changes donc by other zopes
would not be ignored.
"""
- for key, action in self.scheduled_action_dict.iteritems():
- if action is UPDATE_ACTION:
- self.memcached_connection.set(key, self.local_cache[key], 0)
- elif action is DELETE_ACTION:
- self.memcached_connection.delete(key, 0)
+ try:
+ for key, action in self.scheduled_action_dict.iteritems():
+ if action is UPDATE_ACTION:
+ self.memcached_connection.set(key, self.local_cache[key], 0)
+ elif action is DELETE_ACTION:
+ self.memcached_connection.delete(key, 0)
+ except:
+ LOG('MemcachedDict', 0, 'An exception occured during _finish : %s' % (traceback.format_exc(), ))
self.scheduled_action_dict.clear()
self.local_cache.clear()
@@ -104,8 +109,6 @@
def __getitem__(self, key):
"""
Get an item from local cache, otherwise from memcached.
- Note that because of memcached python client limitations, it never
- raises KeyError.
"""
# We need to register in this function too to be able to flush cache at
# transaction end.
@@ -113,6 +116,8 @@
result = self.local_cache.get(key, MARKER)
if result is MARKER:
result = self.memcached_connection.get(key)
+ if result is None:
+ raise KeyError, 'Key %s not found.' % (key, )
self.local_cache[key] = result
return result
@@ -135,25 +140,28 @@
self.scheduled_action_dict[key] = DELETE_ACTION
self.local_cache[key] = None
- def set(self, key, val, time=0):
+ def set(self, key, value):
"""
Set an item to local cache and schedule update of memcached.
"""
return self.__setitem__(key, value)
- def get(self, key, default=MARKER):
+ def get(self, key, default=None):
"""
Get an item from local cache, otherwise from memcached.
Note that because __getitem__ never raises error, 'default' will never
be used (None will be returned instead).
"""
- return self.__getitem__(key)
+ try:
+ return self.__getitem__(key)
+ except KeyError:
+ return default
class SharedDict:
"""
Class to make possible for multiple "users" to store data in the same
- dictionnary without risking to overwrite other's data.
- Each "user" of the dictionnary must get an instance of this class.
+ dictionary without risking to overwrite other's data.
+ Each "user" of the dictionary must get an instance of this class.
TODO:
- handle persistence ?
@@ -162,53 +170,55 @@
def __init__(self, dictionary, prefix):
"""
dictionary
- Instance of dictionnary to share.
+ Instance of dictionary to share.
prefix
Prefix used by the "user" owning an instance of this class.
"""
- self._v_dictionary = dictionary
+ self._dictionary = dictionary
self.prefix = prefix
def _prefixKey(self, key):
"""
Prefix key with self.prefix .
"""
+ if not isinstance(key, basestring):
+ raise TypeError, 'Key %s is not a string. Only strings are supported as key in SharedDict' % (repr(key), )
return '%s_%s' % (self.prefix, key)
def __getitem__(self, key):
"""
Get item from memcached.
"""
- return self._v_dictionary.__getitem__(self._prefixKey(key))
+ return self._dictionary.__getitem__(self._prefixKey(key))
def __setitem__(self, key, value):
"""
Put item in memcached.
"""
- self._v_dictionary.__setitem__(self._prefixKey(key), value)
+ self._dictionary.__setitem__(self._prefixKey(key), value)
def __delitem__(self, key):
"""
Delete item from memcached.
"""
- self._v_dictionary.__delitem__(self._prefixKey(key))
+ self._dictionary.__delitem__(self._prefixKey(key))
# These are the method names called by zope
__guarded_setitem__ = __setitem__
__guarded_getitem__ = __getitem__
__guarded_delitem__ = __delitem__
- def get(self, key, default=MARKER):
+ def get(self, key, default=None):
"""
Get item from memcached.
"""
- return self.__getitem__(key)
+ return self._dictionary.get(self._prefixKey(key), default)
def set(self, key, value):
"""
Put item in memcached.
"""
- self.__setitem__(key, value)
+ self._dictionary.set(self._prefixKey(key), value)
allow_class(SharedDict)
@@ -232,10 +242,11 @@
Return used memcached dict.
Create it if does not exist.
"""
- dictionary = getattr(self, '_v_memcached_dict', None)
- if dictionary is None:
- dictionary = MemcachedDict(self.getServerAddress())
- setattr(self, '_v_memcached_dict', dictionary)
+ try:
+ dictionary = self._v_memcached_dict
+ except AttributeError:
+ dictionary = MemcachedDict(self.getServerAddressList())
+ self._v_memcached_dict = dictionary
return dictionary
security.declareProtected(Permissions.AccessContentsInformation, 'getMemcacheDict')
@@ -246,31 +257,47 @@
key_prefix
Mendatory argument allowing different tool users from sharing the same
- dictionnary key namespace.
+ dictionary key namespace.
"""
return SharedDict(dictionary=self._getMemcachedDict(), prefix=key_prefix)
security.declareProtected(Permissions.ModifyPortalContent, 'setServerAddress')
def setServerAddress(self, value):
"""
+ Set a memcached server address.
+ """
+ self.setServerAddressList([value, ])
+ self.server_address_list = [value, ]
+ self._v_memcached_dict = None
+
+ security.declareProtected(Permissions.AccessContentsInformation, 'getServerAddress')
+ def getServerAddress(self):
+ """
+ Return server address.
+ """
+ return self.getServerAddressList()[0]
+
+ def getServerAddressList(self):
+ """
+ Get the list of memcached servers to use.
+ Defaults to ['127.0.0.1:11211', ].
+ """
+ return getattr(self, 'server_address_list', ['127.0.0.1:11211', ])
+
+ def setServerAddressList(self, value):
+ """
+ Set the list of memcached servers to use.
+
Upon server address change, force next access to memcached dict to
reconnect to new ip.
-
+
This is safe in multi zope environment, since we modify self which is
persistent. Then all zopes will have to reload this tool instance, and
loose their volatile properties in the process, which will force them
to reconnect to memcached.
"""
- self.server_address = value
- setattr(self, '_v_memcached_dict', None)
-
- security.declareProtected(Permissions.AccessContentsInformation, 'getServerAddress')
- def getServerAddress(self):
- """
- Return server address.
- Defaults to 127.0.0.1:11211 if not set.
- """
- return getattr(self, 'server_address', '127.0.0.1:11211')
+ self.server_address_list = value
+ self._v_memcached_dict = None
else:
@@ -281,20 +308,27 @@
id = "portal_memcached"
meta_type = "ERP5 Memcached Tool"
portal_type = "Memcached Tool"
+ title = "DISABLED"
security = ClassSecurityInfo()
manage_options = ({'label': 'Configure',
'action': 'memcached_tool_configure',
},) + BaseTool.manage_options
- def getMemcachedDict(self, *args, **kw):
+ def failingMethod(self, *args, **kw):
"""
if this function is called and memcachedtool is disabled, fail loudly
with a meaningfull message.
"""
from Products.ERP5Type import memcached_tool_enable_path
- raise NotImplementedError, 'MemcachedTool is disabled. You should ask the'\
- 'server administrator to enable it by creating the file %s' % (memcached_tool_enable_path, )
-
- memcached_tool_configure = getMemcachedDict = setServerAddress = getMemcachedDict
-
+ raise RuntimeError, 'MemcachedTool is disabled. You should ask'\
+ ' the server administrator to enable it by creating the file %s' % \
+ (memcached_tool_enable_path, )
+
+ setServerAddress = failingMethod
+ getServerAddress = failingMethod
+ getServerAddressList = failingMethod
+ setServerAddressList = failingMethod
+ memcached_tool_configure = failingMethod
+ getMemcachedDict = failingMethod
+
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