Add methods for cleaning up after forking

Relates to #141

cassandra/connection.py

@@ -187,6 +187,14 @@ class Connection(object):
         """
         pass
 
+    @classmethod
+    def handle_fork(self):
+        """
+        Called after a forking.  This should cleanup any remaining reactor state
+        from the parent process.
+        """
+        pass
+
     def close(self):
         raise NotImplementedError()
 

cassandra/io/asyncorereactor.py

@@ -146,6 +146,12 @@ class AsyncoreConnection(Connection, asyncore.dispatcher):
         if not cls._loop:
             cls._loop = AsyncoreLoop()
 
+    @classmethod
+    def handle_fork(cls):
+        if cls._loop:
+            cls._loop._cleanup()
+            cls._loop = None
+
     @classmethod
     def factory(cls, *args, **kwargs):
         timeout = kwargs.pop('timeout', 5.0)

cassandra/io/libevreactor.py

@@ -227,6 +227,12 @@ class LibevConnection(Connection):
         if not cls._libevloop:
             cls._libevloop = LibevLoop()
 
+    @classmethod
+    def handle_fork(cls):
+        if cls._libevloop:
+            cls._libevloop._cleanup()
+            cls._libevloop = None
+
     @classmethod
     def factory(cls, *args, **kwargs):
         timeout = kwargs.pop('timeout', 5.0)