Made aio_pika client manager more robust and efficient (Fixes #1142)

Author: miguelgrinberg

src/socketio/asyncio_aiopika_manager.py

@@ -44,9 +44,10 @@ def __init__(self, url='amqp://guest:guest@localhost:5672//',
                                '(Run "pip install aio_pika" in your '
                                'virtualenv).')
         self.url = url
-        self.listener_connection = None
-        self.listener_channel = None
-        self.listener_queue = None
+        self._lock = asyncio.Lock()
+        self.publisher_connection = None
+        self.publisher_channel = None
+        self.publisher_exchange = None
         super().__init__(channel=channel, write_only=write_only, logger=logger)
 
     async def _connection(self):
@@ -66,41 +67,60 @@ async def _queue(self, channel, exchange):
         return queue
 
     async def _publish(self, data):
-        connection = await self._connection()
-        channel = await self._channel(connection)
-        exchange = await self._exchange(channel)
-        await exchange.publish(
-            aio_pika.Message(body=pickle.dumps(data),
-                             delivery_mode=aio_pika.DeliveryMode.PERSISTENT),
-            routing_key='*'
-        )
-
-    async def _listen(self):
-        retry_sleep = 1
-        while True:
-            try:
-                if self.listener_connection is None:
-                    self.listener_connection = await self._connection()
-                    self.listener_channel = await self._channel(
-                        self.listener_connection
+        if self.publisher_connection is None:
+            async with self._lock:
+                if self.publisher_connection is None:
+                    self.publisher_connection = await self._connection()
+                    self.publisher_channel = await self._channel(
+                        self.publisher_connection
                     )
-                    await self.listener_channel.set_qos(prefetch_count=1)
-                    exchange = await self._exchange(self.listener_channel)
-                    self.listener_queue = await self._queue(
-                        self.listener_channel, exchange
+                    self.publisher_exchange = await self._exchange(
+                        self.publisher_channel
                     )
-                    retry_sleep = 1
-
-                async with self.listener_queue.iterator() as queue_iter:
-                    async for message in queue_iter:
-                        async with message.process():
-                            yield pickle.loads(message.body)
-            except Exception:
-                self._get_logger().error('Cannot receive from rabbitmq... '
-                                         'retrying in '
-                                         '{} secs'.format(retry_sleep))
-                self.listener_connection = None
-                await asyncio.sleep(retry_sleep)
-                retry_sleep *= 2
-                if retry_sleep > 60:
-                    retry_sleep = 60
+        retry = True
+        while True:
+            try:
+                await self.publisher_exchange.publish(
+                    aio_pika.Message(
+                        body=pickle.dumps(data),
+                        delivery_mode=aio_pika.DeliveryMode.PERSISTENT
+                    ), routing_key='*',
+                )
+                return
+            except aio_pika.AMQPException:
+                if retry:
+                    self._get_logger().error('Cannot publish to rabbitmq... '
+                                             'retrying')
+                    retry = False
+                else:
+                    self._get_logger().error(
+                        'Cannot publish to rabbitmq... giving up')
+                    break
+            except aio_pika.exceptions.ChannelInvalidStateError:
+                # aio_pika raises this exception when the task is cancelled
+                raise asyncio.CancelledError()
+
+    async def _listen(self):
+        async with (await self._connection()) as connection:
+            channel = await self._channel(connection)
+            await channel.set_qos(prefetch_count=1)
+            exchange = await self._exchange(channel)
+            queue = await self._queue(channel, exchange)
+
+            retry_sleep = 1
+            while True:
+                try:
+                    async with queue.iterator() as queue_iter:
+                        async for message in queue_iter:
+                            async with message.process():
+                                yield pickle.loads(message.body)
+                                retry_sleep = 1
+                except aio_pika.AMQPException:
+                    self._get_logger().error(
+                        'Cannot receive from rabbitmq... '
+                        'retrying in {} secs'.format(retry_sleep))
+                    await asyncio.sleep(retry_sleep)
+                    retry_sleep = min(retry_sleep * 2, 60)
+                except aio_pika.exceptions.ChannelInvalidStateError:
+                    # aio_pika raises this exception when the task is cancelled
+                    raise asyncio.CancelledError()