Source Code for Module buildslave.pbutil

  1   
  2  """Base classes handy for use with PB clients. 
  3  """ 
  4   
  5  from twisted.spread import pb 
  6   
  7  from twisted.spread.pb import PBClientFactory 
  8  from twisted.internet import protocol, reactor 
  9  from twisted.python import log 
 10   
 11 -class ReconnectingPBClientFactory(PBClientFactory, 
 12                                    protocol.ReconnectingClientFactory): 
 13      """Reconnecting client factory for PB brokers. 
 14   
 15      Like PBClientFactory, but if the connection fails or is lost, the factory 
 16      will attempt to reconnect. 
 17   
 18      Instead of using f.getRootObject (which gives a Deferred that can only 
 19      be fired once), override the gotRootObject method. 
 20   
 21      Instead of using the newcred f.login (which is also one-shot), call 
 22      f.startLogin() with the credentials and client, and override the 
 23      gotPerspective method. 
 24   
 25      gotRootObject and gotPerspective will be called each time the object is 
 26      received (once per successful connection attempt). You will probably want 
 27      to use obj.notifyOnDisconnect to find out when the connection is lost. 
 28   
 29      If an authorization error occurs, failedToGetPerspective() will be 
 30      invoked. 
 31   
 32      To use me, subclass, then hand an instance to a connector (like 
 33      TCPClient). 
 34      """ 
 35   
 36      # hung connections wait for a relatively long time, since a busy master may 
 37      # take a while to get back to us. 
 38      hungConnectionTimer = None 
 39      HUNG_CONNECTION_TIMEOUT = 120 
 40   
 41 -    def clientConnectionFailed(self, connector, reason): 
 42          PBClientFactory.clientConnectionFailed(self, connector, reason) 
 43          if self.continueTrying: 
 44              self.connector = connector 
 45              self.retry() 
 46   
 47 -    def clientConnectionLost(self, connector, reason): 
 48          PBClientFactory.clientConnectionLost(self, connector, reason, 
 49                                               reconnecting=True) 
 50          RCF = protocol.ReconnectingClientFactory 
 51          RCF.clientConnectionLost(self, connector, reason) 
 52   
 53 -    def startedConnecting(self, connector): 
 54          self.startHungConnectionTimer(connector) 
 55   
 56 -    def clientConnectionMade(self, broker): 
 57          self.resetDelay() 
 58          PBClientFactory.clientConnectionMade(self, broker) 
 59          self.doLogin(self._root) 
 60          self.gotRootObject(self._root) 
 61   
 62      # newcred methods 
 63   
 64 -    def login(self, *args): 
 65          raise RuntimeError, "login is one-shot: use startLogin instead" 
 66   
 67 -    def startLogin(self, credentials, client=None): 
 68          self._credentials = credentials 
 69          self._client = client 
 70   
 71 -    def doLogin(self, root): 
 72          # newcred login() 
 73          d = self._cbSendUsername(root, self._credentials.username, 
 74                                   self._credentials.password, self._client) 
 75          d.addCallbacks(self.gotPerspective, self.failedToGetPerspective) 
 76   
 77      # timer for hung connections 
 78   
 79 -    def startHungConnectionTimer(self, connector): 
 80          self.stopHungConnectionTimer() 
 81          def hungConnection(): 
 82              log.msg("connection attempt timed out (is the port number correct?)") 
 83              self.hungConnectionTimer = None 
 84              connector.disconnect() 
 85              # (this will trigger the retry) 
 86          self.hungConnectionTimer = reactor.callLater(self.HUNG_CONNECTION_TIMEOUT, hungConnection) 
 87   
 88 -    def stopHungConnectionTimer(self): 
 89          if self.hungConnectionTimer: 
 90              self.hungConnectionTimer.cancel() 
 91          self.hungConnectionTimer = None 
 92   
 93      # methods to override 
 94   
 95 -    def gotPerspective(self, perspective): 
 96          """The remote avatar or perspective (obtained each time this factory 
 97          connects) is now available.""" 
 98          self.stopHungConnectionTimer() 
 99   
100 -    def gotRootObject(self, root): 
101          """The remote root object (obtained each time this factory connects) 
102          is now available. This method will be called each time the connection 
103          is established and the object reference is retrieved.""" 
104          self.stopHungConnectionTimer() 
105   
106 -    def failedToGetPerspective(self, why): 
107          """The login process failed, most likely because of an authorization 
108          failure (bad password), but it is also possible that we lost the new 
109          connection before we managed to send our credentials. 
110          """ 
111          log.msg("ReconnectingPBClientFactory.failedToGetPerspective") 
112          self.stopHungConnectionTimer() 
113          if why.check(pb.PBConnectionLost): 
114              log.msg("we lost the brand-new connection") 
115              # retrying might help here, let clientConnectionLost decide 
116              return 
117          # probably authorization 
118          self.stopTrying() # logging in harder won't help 
119          log.err(why) 
120          reactor.stop() 
121