Prefer assert or more-specific error to IllegalState / IllegalArgument

1 files changed, 7 insertions, 7 deletions

diff --git a/kafka/client_async.py b/kafka/client_async.py
index 87d616c..d71c9a4 100644
--- a/kafka/client_async.py
+++ b/kafka/client_async.py
@@ -131,10 +131,9 @@ class KafkaClient(object):
         return conn.state is ConnectionStates.DISCONNECTED and not conn.blacked_out()
 
     def _initiate_connect(self, node_id):
-        """Initiate a connection to the given node"""
+        """Initiate a connection to the given node (must be in metadata)"""
         broker = self.cluster.broker_metadata(node_id)
-        if not broker:
-            raise Errors.IllegalArgumentError('Broker %s not found in current cluster metadata', node_id)
+        assert broker, 'Broker id %s not in current metadata' % node_id
 
         if node_id not in self._conns:
             log.debug("Initiating connection to node %s at %s:%s",
@@ -144,8 +143,7 @@ class KafkaClient(object):
         return self._finish_connect(node_id)
 
     def _finish_connect(self, node_id):
-        if node_id not in self._conns:
-            raise Errors.IllegalArgumentError('Node %s not found in connections', node_id)
+        assert node_id in self._conns, '%s is not in current conns' % node_id
         state = self._conns[node_id].connect()
         if state is ConnectionStates.CONNECTING:
             self._connecting.add(node_id)
@@ -242,13 +240,15 @@ class KafkaClient(object):
             request (Struct): request object (not-encoded)
 
         Raises:
-            IllegalStateError: if node_id is not ready
+            NodeNotReadyError: if node_id is not ready
 
         Returns:
             Future: resolves to Response struct
         """
         if not self._can_send_request(node_id):
-            raise Errors.IllegalStateError("Attempt to send a request to node %s which is not ready." % node_id)
+            raise Errors.NodeNotReadyError("Attempt to send a request to node"
+                                           " which is not ready (node id %s)."
+                                           % node_id)
 
         # Every request gets a response, except one special case:
         expect_response = True