Add a transport cleanup() method

Pretty obvious that we need this.

The rabbit/qpid implementations just empty the connection pool, in the
same way their module-level cleanup() methods do now.

Change-Id: I70ba5cab3eb7a30f74cdd6cafe60087769a77b57

oslo/messaging/_drivers/amqpdriver.py

@@ -322,3 +322,8 @@ class AMQPDriverBase(base.BaseDriver):
         conn.declare_fanout_consumer(target.topic, listener)
 
         return listener
+
+    def cleanup(self):
+        if self._connection_pool:
+            self._connection_pool.empty()
+        self._connection_pool = None

oslo/messaging/_drivers/base.py

@@ -72,3 +72,7 @@ class BaseDriver(object):
     @abc.abstractmethod
     def listen(self, target):
         """Construct a Listener for the given target."""
+
+    @abc.abstractmethod
+    def cleanup(self):
+        """Release all resources."""

oslo/messaging/_drivers/impl_fake.py

@@ -164,3 +164,6 @@ class FakeDriver(base.BaseDriver):
                                       self._default_exchange)
 
         return FakeListener(self, target, exchange)
+
+    def cleanup(self):
+        pass

oslo/messaging/transport.py

@@ -85,6 +85,10 @@ class Transport(object):
     def _listen(self, target):
         return self._driver.listen(target)
 
+    def cleanup(self):
+        """Release all resources associated with this transport."""
+        self._driver.cleanup()
+
 
 class InvalidTransportURL(exceptions.MessagingException):
     """Raised if transport URL is invalid."""

tests/test_rabbit.py

@@ -29,9 +29,6 @@ class TestRabbitDriver(test_utils.BaseTestCase):
         self.config(rpc_backend='rabbit')
         self.config(fake_rabbit=True)
 
-        # FIXME(markmc): this should be a cleanup method on the driver itself
-        self.addCleanup(rabbit_driver.cleanup)
-
     def test_driver_load(self):
         transport = messaging.get_transport(self.conf)
         self.assertTrue(isinstance(transport._driver,
@@ -39,6 +36,8 @@ class TestRabbitDriver(test_utils.BaseTestCase):
 
     def test_send_receive(self):
         transport = messaging.get_transport(self.conf)
+        self.addCleanup(transport.cleanup)
+
         driver = transport._driver
 
         target = messaging.Target(topic='testtopic')