Add state_change_callback to BrokerConnection

kafka/conn.py

@@ -31,6 +31,7 @@ DEFAULT_KAFKA_PORT = 9092
 
 
 class ConnectionStates(object):
+    DISCONNECTING = '<disconnecting>'
     DISCONNECTED = '<disconnected>'
     CONNECTING = '<connecting>'
     CONNECTED = '<connected>'
@@ -49,6 +50,7 @@ class BrokerConnection(object):
         'receive_buffer_bytes': None,
         'send_buffer_bytes': None,
         'api_version': (0, 8, 2),  # default to most restrictive
+        'state_change_callback': lambda conn: True,
     }
 
     def __init__(self, host, port, afi, **configs):
@@ -87,6 +89,7 @@ class BrokerConnection(object):
             self._sock.setblocking(False)
             self.state = ConnectionStates.CONNECTING
             self.last_attempt = time.time()
+            self.config['state_change_callback'](self)
 
         if self.state is ConnectionStates.CONNECTING:
             # in non-blocking mode, use repeated calls to socket.connect_ex
@@ -101,6 +104,7 @@ class BrokerConnection(object):
             if not ret or ret == errno.EISCONN:
                 log.debug('%s: established TCP connection', str(self))
                 self.state = ConnectionStates.CONNECTED
+                self.config['state_change_callback'](self)
 
             # Connection failed
             # WSAEINVAL == 10022, but errno.WSAEINVAL is not available on non-win systems
@@ -151,6 +155,9 @@ class BrokerConnection(object):
                 will be failed with this exception.
                 Default: kafka.errors.ConnectionError.
         """
+        if self.state is not ConnectionStates.DISCONNECTED:
+            self.state = ConnectionStates.DISCONNECTING
+            self.config['state_change_callback'](self)
         if self._sock:
             self._sock.close()
             self._sock = None
@@ -165,6 +172,7 @@ class BrokerConnection(object):
         while self.in_flight_requests:
             ifr = self.in_flight_requests.popleft()
             ifr.future.failure(error)
+        self.config['state_change_callback'](self)
 
     def send(self, request, expect_response=True):
         """send request, return Future()