Cascade IRC connections.

This makes it so that, if we are joining 12 channels as 12 bots, we won't try
to do them all at the same time.  We'll connect to one, and then once that is
started we'll wait 1 second and then start the second connection.  The start of
that one will wait 1 second and trigger the third, etc...

fedmsg/consumers/ircbot.py

@@ -28,6 +28,7 @@
 from fedmsg.meta import _
 
 import copy
+import functools
 import re
 import time
 import pygments
@@ -148,7 +149,7 @@ class Fedmsg2IRCFactory(protocol.ClientFactory):
     protocol = make_irc_client
 
     def __init__(self, channel, nickname, filters,
-                 pretty, terse, short, rate, parent_consumer):
+                 pretty, terse, short, rate, parent_consumer, ready):
         self.channel = channel
         self.nickname = nickname
         self.filters = filters
@@ -157,8 +158,16 @@ def __init__(self, channel, nickname, filters,
         self.short = short
         self.rate = rate
         self.parent_consumer = parent_consumer
+        self.ready = ready
         self.log = logging.getLogger("moksha.hub")
 
+    def startedConnecting(self, connector):
+        if self.ready:
+            # If we're joining 12 channels, join one of them first.  Once
+            # joining, wait one second and start joining the second one.  That
+            # one should trigger joining the third one...
+            reactor.callLater(1, self.ready)
+
     def clientConnectionLost(self, connector, reason):
         if self.parent_consumer.die:
             self.log.info("Lost connection.  Not reconnecting to IRC.")
@@ -196,6 +205,7 @@ def __init__(self, hub):
             return
 
         irc_settings = hub.config.get('irc')
+        callback = None  # Keep track of the last factory we created
         for settings in irc_settings:
             network = settings.get('network', 'irc.freenode.net')
             port = settings.get('port', 6667)
@@ -216,9 +226,22 @@ def __init__(self, hub):
 
             filters = self.compile_filters(settings.get('filters', None))
 
+
             factory = Fedmsg2IRCFactory(
-                channel, nickname, filters, pretty, terse, short, rate, self)
-            reactor.connectTCP(network, port, factory, timeout=timeout)
+                channel, nickname, filters,
+                pretty, terse, short, rate,
+                self, ready=callback,
+            )
+            callback = functools.partial(
+                reactor.connectTCP,
+                network, port, factory,
+                timeout=timeout,
+            )
+
+        # Call only the very last one.
+        # When it is done, it will call the second to last one, which when it
+        # is done will call the third to last one, etc..
+        callback()
 
     def add_irc_client(self, client):
         self.irc_clients.append(client)