Merge pull request #122 from mrtheb/multihosts

Support for multiple hosts on KafkaClient boostrap (improves on #70)

1 files changed, 18 insertions, 7 deletions

diff --git a/kafka/client.py b/kafka/client.py
index 155f658..96cc1df 100644
--- a/kafka/client.py
+++ b/kafka/client.py
@@ -10,7 +10,7 @@ from kafka.common import (ErrorMapping, TopicAndPartition,
                           BrokerResponseError, PartitionUnavailableError,
                           KafkaUnavailableError, KafkaRequestError)
 
-from kafka.conn import KafkaConnection, DEFAULT_SOCKET_TIMEOUT_SECONDS
+from kafka.conn import collect_hosts, KafkaConnection, DEFAULT_SOCKET_TIMEOUT_SECONDS
 from kafka.protocol import KafkaProtocol
 
 log = logging.getLogger("kafka")
@@ -24,14 +24,15 @@ class KafkaClient(object):
     # NOTE: The timeout given to the client should always be greater than the
     # one passed to SimpleConsumer.get_message(), otherwise you can get a
     # socket timeout.
-    def __init__(self, host, port, client_id=CLIENT_ID,
+    def __init__(self, hosts, client_id=CLIENT_ID,
                  timeout=DEFAULT_SOCKET_TIMEOUT_SECONDS):
         # We need one connection to bootstrap
         self.client_id = client_id
         self.timeout = timeout
-        self.conns = {               # (host, port) -> KafkaConnection
-            (host, port): KafkaConnection(host, port, timeout=timeout)
-        }
+        self.hosts = collect_hosts(hosts)
+
+        # create connections only when we need them
+        self.conns = {}
         self.brokers = {}            # broker_id -> BrokerMetadata
         self.topics_to_brokers = {}  # topic_id -> broker_id
         self.topic_partitions = {}   # topic_id -> [0, 1, 2, ...]
@@ -41,6 +42,15 @@ class KafkaClient(object):
     #   Private API  #
     ##################
 
+    def _get_conn(self, host, port):
+        "Get or create a connection to a broker using host and port"
+
+        host_key = (host, port)
+        if host_key not in self.conns:
+            self.conns[host_key] = KafkaConnection(host, port)
+
+        return self.conns[host_key]
+
     def _get_conn_for_broker(self, broker):
         """
         Get or create a connection to a broker
@@ -49,7 +59,7 @@ class KafkaClient(object):
             self.conns[(broker.host, broker.port)] = \
                 KafkaConnection(broker.host, broker.port, timeout=self.timeout)
 
-        return self.conns[(broker.host, broker.port)]
+        return self._get_conn(broker.host, broker.port)
 
     def _get_leader_for_partition(self, topic, partition):
         key = TopicAndPartition(topic, partition)
@@ -72,7 +82,8 @@ class KafkaClient(object):
         Attempt to send a broker-agnostic request to one of the available
         brokers. Keep trying until you succeed.
         """
-        for conn in self.conns.values():
+        for (host, port) in self.hosts:
+            conn = self._get_conn(host, port)
             try:
                 conn.send(requestId, request)
                 response = conn.recv(requestId)