Source Code for Module ZenUtils.PBUtil

  1  ########################################################################### 
  2  # 
  3  # This program is part of Zenoss Core, an open source monitoring platform. 
  4  # Copyright (C) 2007, Zenoss Inc. 
  5  # 
  6  # This program is free software; you can redistribute it and/or modify it 
  7  # under the terms of the GNU General Public License version 2 as published by 
  8  # the Free Software Foundation. 
  9  # 
 10  # For complete information please visit: http://www.zenoss.com/oss/ 
 11  # 
 12  ########################################################################### 
 13   
 14  # taken from r1.10 of buildbot.sf.net/buildbot/pbutil.py 
 15   
 16  # flumotion has nearly the same code 
 17   
 18  """Base classes handy for use with PB clients. 
 19  """ 
 20   
 21  from twisted.spread import pb 
 22   
 23  from twisted.spread.pb import PBClientFactory 
 24  from twisted.internet import protocol 
 25  from twisted.python import log 
 26   
 27 -class ReconnectingPBClientFactory(PBClientFactory, 
 28                                    protocol.ReconnectingClientFactory): 
 29      """Reconnecting client factory for PB brokers. 
 30   
 31      Like PBClientFactory, but if the connection fails or is lost, the factory 
 32      will attempt to reconnect. 
 33   
 34      Instead of using f.getRootObject (which gives a Deferred that can only 
 35      be fired once), override the gotRootObject method. 
 36   
 37      Instead of using the newcred f.login (which is also one-shot), call 
 38      f.startLogin() with the credentials and client, and override the 
 39      gotPerspective method. 
 40   
 41      Instead of using the oldcred f.getPerspective (also one-shot), call 
 42      f.startGettingPerspective() with the same arguments, and override 
 43      gotPerspective. 
 44   
 45      gotRootObject and gotPerspective will be called each time the object is 
 46      received (once per successful connection attempt). You will probably want 
 47      to use obj.notifyOnDisconnect to find out when the connection is lost. 
 48   
 49      If an authorization error occurs, failedToGetPerspective() will be 
 50      invoked. 
 51   
 52      To use me, subclass, then hand an instance to a connector (like 
 53      TCPClient). 
 54      """ 
 55   
 56 -    def __init__(self): 
 57          PBClientFactory.__init__(self) 
 58          self._doingLogin = False 
 59          self._doingGetPerspective = False 
 60   
 61 -    def clientConnectionFailed(self, connector, reason): 
 62          PBClientFactory.clientConnectionFailed(self, connector, reason) 
 63          # Twisted-1.3 erroneously abandons the connection on non-UserErrors. 
 64          # To avoid this bug, don't upcall, and implement the correct version 
 65          # of the method here. 
 66          if self.continueTrying: 
 67              self.connector = connector 
 68              self.retry() 
 69   
 70 -    def clientConnectionLost(self, connector, reason): 
 71          PBClientFactory.clientConnectionLost(self, connector, reason, 
 72                                               reconnecting=True) 
 73          RCF = protocol.ReconnectingClientFactory 
 74          RCF.clientConnectionLost(self, connector, reason) 
 75   
 76 -    def clientConnectionMade(self, broker): 
 77          self.resetDelay() 
 78          PBClientFactory.clientConnectionMade(self, broker) 
 79          if self._doingLogin: 
 80              self.doLogin(self._root) 
 81          if self._doingGetPerspective: 
 82              self.doGetPerspective(self._root) 
 83          self.gotRootObject(self._root) 
 84   
 85 -    def __getstate__(self): 
 86          # this should get folded into ReconnectingClientFactory 
 87          d = self.__dict__.copy() 
 88          d['connector'] = None 
 89          d['_callID'] = None 
 90          return d 
 91   
 92      # oldcred methods 
 93   
 94 -    def getPerspective(self, *args): 
 95          raise RuntimeError, "getPerspective is one-shot: use startGettingPerspective instead" 
 96   
 97 -    def startGettingPerspective(self, username, password, serviceName, 
 98                                  perspectiveName=None, client=None): 
 99          self._doingGetPerspective = True 
100          if perspectiveName == None: 
101              perspectiveName = username 
102          self._oldcredArgs = (username, password, serviceName, 
103                               perspectiveName, client) 
104   
105 -    def doGetPerspective(self, root): 
106          # oldcred getPerspective() 
107          (username, password, 
108           serviceName, perspectiveName, client) = self._oldcredArgs 
109          d = self._cbAuthIdentity(root, username, password) 
110          d.addCallback(self._cbGetPerspective, 
111                        serviceName, perspectiveName, client) 
112          d.addCallbacks(self.gotPerspective, self.failedToGetPerspective) 
113   
114   
115      # newcred methods 
116   
117 -    def login(self, *args): 
118          raise RuntimeError, "login is one-shot: use startLogin instead" 
119   
120 -    def startLogin(self, credentials, client=None): 
121          self._credentials = credentials 
122          self._client = client 
123          self._doingLogin = True 
124   
125 -    def doLogin(self, root): 
126          # newcred login() 
127          d = self._cbSendUsername(root, self._credentials.username, 
128                                   self._credentials.password, self._client) 
129          d.addCallbacks(self.gotPerspective, self.failedToGetPerspective) 
130          return d 
131   
132   
133      # methods to override 
134   
135 -    def gotPerspective(self, perspective): 
136          """The remote avatar or perspective (obtained each time this factory 
137          connects) is now available.""" 
138          pass 
139   
140 -    def gotRootObject(self, root): 
141          """The remote root object (obtained each time this factory connects) 
142          is now available. This method will be called each time the connection 
143          is established and the object reference is retrieved.""" 
144          pass 
145   
146 -    def failedToGetPerspective(self, why): 
147          """The login process failed, most likely because of an authorization 
148          failure (bad password), but it is also possible that we lost the new 
149          connection before we managed to send our credentials. 
150          """ 
151          log.msg("ReconnectingPBClientFactory.failedToGetPerspective") 
152          if why.check(pb.PBConnectionLost): 
153              log.msg("we lost the brand-new connection") 
154              # retrying might help here, let clientConnectionLost decide 
155              return 
156          # probably authorization 
157          self.stopTrying() # logging in harder won't help 
158          log.err(why) 
159