Reduce client poll timeout when no ifrs

Author: dpkp

kafka/client_async.py

@@ -588,6 +588,9 @@ def poll(self, timeout_ms=None, future=None):
                         metadata_timeout_ms,
                         idle_connection_timeout_ms,
                         self.config['request_timeout_ms'])
+                    # if there are no requests in flight, do not block longer than the retry backoff
+                    if self.in_flight_request_count() == 0:
+                        timeout = min(timeout, self.config['retry_backoff_ms'])
                     timeout = max(0, timeout / 1000)  # avoid negative timeouts
 
                 self._poll(timeout)

test/test_client_async.py

@@ -229,6 +229,8 @@ def test_send(cli, conn):
 def test_poll(mocker):
     metadata = mocker.patch.object(KafkaClient, '_maybe_refresh_metadata')
     _poll = mocker.patch.object(KafkaClient, '_poll')
+    ifrs = mocker.patch.object(KafkaClient, 'in_flight_request_count')
+    ifrs.return_value = 1
     cli = KafkaClient(api_version=(0, 9))
 
     # metadata timeout wins
@@ -245,6 +247,11 @@ def test_poll(mocker):
     cli.poll()
     _poll.assert_called_with(cli.config['request_timeout_ms'] / 1000.0)
 
+    # If no in-flight-requests, drop timeout to retry_backoff_ms
+    ifrs.return_value = 0
+    cli.poll()
+    _poll.assert_called_with(cli.config['retry_backoff_ms'] / 1000.0)
+
 
 def test__poll():
     pass
@@ -300,12 +307,14 @@ def client(mocker):
 
 def test_maybe_refresh_metadata_ttl(mocker, client):
     client.cluster.ttl.return_value = 1234
+    mocker.patch.object(KafkaClient, 'in_flight_request_count', return_value=1)
 
     client.poll(timeout_ms=12345678)
     client._poll.assert_called_with(1.234)
 
 
 def test_maybe_refresh_metadata_backoff(mocker, client):
+    mocker.patch.object(KafkaClient, 'in_flight_request_count', return_value=1)
     now = time.time()
     t = mocker.patch('time.time')
     t.return_value = now
@@ -316,6 +325,7 @@ def test_maybe_refresh_metadata_backoff(mocker, client):
 
 def test_maybe_refresh_metadata_in_progress(mocker, client):
     client._metadata_refresh_in_progress = True
+    mocker.patch.object(KafkaClient, 'in_flight_request_count', return_value=1)
 
     client.poll(timeout_ms=12345678)
     client._poll.assert_called_with(9999.999) # request_timeout_ms
@@ -324,6 +334,7 @@ def test_maybe_refresh_metadata_in_progress(mocker, client):
 def test_maybe_refresh_metadata_update(mocker, client):
     mocker.patch.object(client, 'least_loaded_node', return_value='foobar')
     mocker.patch.object(client, '_can_send_request', return_value=True)
+    mocker.patch.object(KafkaClient, 'in_flight_request_count', return_value=1)
     send = mocker.patch.object(client, 'send')
 
     client.poll(timeout_ms=12345678)
@@ -338,6 +349,7 @@ def test_maybe_refresh_metadata_cant_send(mocker, client):
     mocker.patch.object(client, '_can_connect', return_value=True)
     mocker.patch.object(client, '_maybe_connect', return_value=True)
     mocker.patch.object(client, 'maybe_connect', return_value=True)
+    mocker.patch.object(KafkaClient, 'in_flight_request_count', return_value=1)
 
     now = time.time()
     t = mocker.patch('time.time')