break up some circular references and close client wake pipe on __del__

kafka/client_async.py

@@ -97,6 +97,10 @@ class KafkaClient(object):
         self._bootstrap(collect_hosts(self.config['bootstrap_servers']))
         self._wake_r, self._wake_w = os.pipe()
 
+    def __del__(self):
+        os.close(self._wake_r)
+        os.close(self._wake_w)
+
     def _bootstrap(self, hosts):
         # Exponential backoff if bootstrap fails
         backoff_ms = self.config['reconnect_backoff_ms'] * 2 ** self._bootstrap_fails

kafka/coordinator/base.py

@@ -2,6 +2,7 @@ import abc
 import copy
 import logging
 import time
+import weakref
 
 import six
 
@@ -85,9 +86,12 @@ class BaseCoordinator(object):
         self.rejoin_needed = True
         self.needs_join_prepare = True
         self.heartbeat = Heartbeat(**self.config)
-        self.heartbeat_task = HeartbeatTask(self)
+        self.heartbeat_task = HeartbeatTask(weakref.proxy(self))
         #self.sensors = GroupCoordinatorMetrics(metrics, metric_group_prefix, metric_tags)
 
+    def __del__(self):
+        self.heartbeat_task.disable()
+
     @abc.abstractmethod
     def protocol_type(self):
         """
@@ -572,6 +576,12 @@ class HeartbeatTask(object):
         self._client = coordinator._client
         self._request_in_flight = False
 
+    def disable(self):
+        try:
+            self._client.unschedule(self)
+        except KeyError:
+            pass
+
     def reset(self):
         # start or restart the heartbeat task to be executed at the next chance
         self._heartbeat.reset_session_timeout()

kafka/coordinator/consumer.py

@@ -4,20 +4,20 @@ import copy
 import collections
 import logging
 import time
+import weakref
 
 import six
 
 from .base import BaseCoordinator
 from .assignors.range import RangePartitionAssignor
 from .assignors.roundrobin import RoundRobinPartitionAssignor
-from .protocol import (
+from .protocol import ConsumerProtocol
-    ConsumerProtocolMemberMetadata, ConsumerProtocolMemberAssignment,
-    ConsumerProtocol)
 from ..common import OffsetAndMetadata, TopicPartition
 from ..future import Future
 from ..protocol.commit import (
     OffsetCommitRequest_v2, OffsetCommitRequest_v1, OffsetCommitRequest_v0,
     OffsetFetchRequest_v0, OffsetFetchRequest_v1)
+from ..util import WeakMethod
 
 import kafka.common as Errors
 
@@ -83,7 +83,7 @@ class ConsumerCoordinator(BaseCoordinator):
         self._partitions_per_topic = {}
         self._cluster = client.cluster
         self._cluster.request_update()
-        self._cluster.add_listener(self._handle_metadata_update)
+        self._cluster.add_listener(WeakMethod(self._handle_metadata_update))
 
         self._auto_commit_task = None
         if self.config['enable_auto_commit']:
@@ -95,13 +95,18 @@ class ConsumerCoordinator(BaseCoordinator):
                 log.warning('group_id is None: disabling auto-commit.')
             else:
                 interval = self.config['auto_commit_interval_ms'] / 1000.0
-                self._auto_commit_task = AutoCommitTask(self, interval)
+                self._auto_commit_task = AutoCommitTask(weakref.proxy(self), interval)
 
         # metrics=None,
         # metric_group_prefix=None,
         # metric_tags=None,
         # self.sensors = ConsumerCoordinatorMetrics(metrics, metric_group_prefix, metric_tags)
 
+    def __del__(self):
+        if self._auto_commit_task:
+            self._auto_commit_task.disable()
+        self._cluster.remove_listener(WeakMethod(self._handle_metadata_update))
+
     def protocol_type(self):
         return ConsumerProtocol.PROTOCOL_TYPE
 

kafka/util.py

@@ -3,6 +3,7 @@ import collections
 import struct
 import sys
 from threading import Thread, Event
+import weakref
 
 import six
 
@@ -151,3 +152,39 @@ class ReentrantTimer(object):
 
     def __del__(self):
         self.stop()
+
+
+class WeakMethod(object):
+    """
+    Callable that weakly references a method and the object it is bound to. It
+    is based on http://stackoverflow.com/a/24287465.
+
+    Arguments:
+
+        object_dot_method: A bound instance method (i.e. 'object.method').
+    """
+    def __init__(self, object_dot_method):
+        try:
+            self.target = weakref.ref(object_dot_method.__self__)
+        except AttributeError:
+            self.target = weakref.ref(object_dot_method.im_self)
+        self._target_id = id(self.target())
+        try:
+            self.method = weakref.ref(object_dot_method.__func__)
+        except AttributeError:
+            self.method = weakref.ref(object_dot_method.im_func)
+        self._method_id = id(self.method())
+
+    def __call__(self, *args, **kwargs):
+        """
+        Calls the method on target with args and kwargs.
+        """
+        return self.method()(self.target(), *args, **kwargs)
+
+    def __hash__(self):
+        return hash(self.target) ^ hash(self.method)
+
+    def __eq__(self, other):
+        if not isinstance(other, WeakMethod):
+            return False
+        return self._target_id == other._target_id and self._method_id == other._method_id

test/test_coordinator.py

@@ -19,6 +19,7 @@ from kafka.protocol.commit import (
     OffsetCommitResponse, OffsetFetchRequest_v0, OffsetFetchRequest_v1,
     OffsetFetchResponse)
 from kafka.protocol.metadata import MetadataResponse
+from kafka.util import WeakMethod
 
 import kafka.common as Errors
 
@@ -46,7 +47,7 @@ def test_init(conn):
 
     # metadata update on init 
     assert cli.cluster._need_update is True
-    assert coordinator._handle_metadata_update in cli.cluster._listeners
+    assert WeakMethod(coordinator._handle_metadata_update) in cli.cluster._listeners
 
 
 @pytest.mark.parametrize("api_version", [(0, 8, 0), (0, 8, 1), (0, 8, 2), (0, 9)])