From 98119e9b9f58e3d5de68dca18e16e9ad8bf77375 Mon Sep 17 00:00:00 2001
From: Dana Powers <dana.powers@rd.io>
Date: Thu, 8 Mar 2018 13:13:00 -0500
Subject: [PATCH] Defer version check until after bootstrap succeeds

---
 kafka/client_async.py | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/kafka/client_async.py b/kafka/client_async.py
index 58155b880..b4366c890 100644
--- a/kafka/client_async.py
+++ b/kafka/client_async.py
@@ -196,6 +196,9 @@ def __init__(self, **configs):
             assert self.config['api_version'] in self.API_VERSIONS, (
                 'api_version [{0}] must be one of: {1}'.format(
                     self.config['api_version'], str(self.API_VERSIONS)))
+        else:
+            # This should get updated after a successful bootstrap
+            self.config['api_version'] = (0, 0)
 
         self.cluster = ClusterMetadata(**self.config)
         self._topics = set()  # empty set will fetch all topic metadata
@@ -228,11 +231,6 @@ def __init__(self, **configs):
 
         self._bootstrap(collect_hosts(self.config['bootstrap_servers']))
 
-        # Check Broker Version if not set explicitly
-        if self.config['api_version'] is None:
-            check_timeout = self.config['api_version_auto_timeout_ms'] / 1000
-            self.config['api_version'] = self.check_version(timeout=check_timeout)
-
     def _bootstrap(self, hosts):
         log.info('Bootstrapping cluster metadata from %s', hosts)
         # Exponential backoff if bootstrap fails
@@ -245,7 +243,7 @@ def _bootstrap(self, hosts):
             time.sleep(next_at - now)
         self._last_bootstrap = time.time()
 
-        if self.config['api_version'] is None or self.config['api_version'] < (0, 10):
+        if self.config['api_version'] < (0, 10):
             metadata_request = MetadataRequest[0]([])
         else:
             metadata_request = MetadataRequest[1](None)
@@ -283,7 +281,13 @@ def _bootstrap(self, hosts):
             else:
                 bootstrap.close()
             self._bootstrap_fails = 0
+
+            # Check Broker Version if not set explicitly
+            if self.config['api_version'] == (0, 0):
+                check_timeout = self.config['api_version_auto_timeout_ms'] / 1000
+                self.config['api_version'] = self.check_version(timeout=check_timeout)
             break
+
         # No bootstrap found...
         else:
             log.error('Unable to bootstrap from %s', hosts)
@@ -821,10 +825,10 @@ def check_version(self, node_id=None, timeout=2, strict=False):
             This is only possible if node_id is None.
 
         Returns: version tuple, i.e. (0, 10), (0, 9), (0, 8, 2), ...
+            (0, 0) returned if the version cannot be determined,
+            typically due to networking.
 
         Raises:
-            NodeNotReadyError (if node_id is provided)
-            NoBrokersAvailable (if node_id is None)
             UnrecognizedBrokerVersion: please file bug if seen!
             AssertionError (if strict=True): please file bug if seen!
         """
@@ -835,7 +839,7 @@ def check_version(self, node_id=None, timeout=2, strict=False):
             # which can block for an increasing backoff period
             try_node = node_id or self.least_loaded_node()
             if try_node is None:
-                raise Errors.NoBrokersAvailable()
+                return (0, 0)
             self._maybe_connect(try_node)
             conn = self._conns[try_node]
 
@@ -847,15 +851,14 @@ def check_version(self, node_id=None, timeout=2, strict=False):
                 version = conn.check_version(timeout=remaining, strict=strict)
                 return version
             except Errors.NodeNotReadyError:
-                # Only raise to user if this is a node-specific request
                 if node_id is not None:
-                    raise
+                    return (0, 0)
             finally:
                 self._refresh_on_disconnects = True
 
         # Timeout
         else:
-            raise Errors.NoBrokersAvailable()
+            return (0, 0)
 
     def wakeup(self):
         with self._wake_lock: