Asynchronous AMQP client for 0.9.1 protocol version
Recommended way (via pip):
Simple echo RPC server:
import asyncio as aio
import logging
import typing as ty
import aio_amqp
logger = logging.getLogger(__name__)
class EchoRpcServer:
_channel_id = 1
def __init__(
self,
rpc_queue_name: str,
heartbeat: ty.Optional[int] = None,
reconnection_interval: int = 10,
loop: ty.Optional[aio.AbstractEventLoop] = None
) -> None:
self._rpc_queue_name = rpc_queue_name
self._reconnection_interval = reconnection_interval
self._loop = loop or aio.get_event_loop()
self._client = aio_amqp.Client(heartbeat=heartbeat, loop=self._loop)
self._tasks = [
self._loop.create_task(self._connect_forever()),
self._loop.create_task(self._handle_messages())
]
async def close(self) -> None:
for task in self._tasks:
if task.done():
continue
task.cancel()
try:
await task
except aio.CancelledError:
pass
async def _handle_messages(self) -> None:
async for message in self._client.delivered_messages():
correlation_id = message.properties.get('correlation_id')
reply_to = message.properties.get('reply_to')
if reply_to is None:
logger.warning("Invalid message properties")
continue
try:
await self._client.basic_ack(self._channel_id, message.delivery_tag)
properties = {}
if correlation_id is not None:
properties = {'correlation_id': correlation_id}
await self._client.basic_publish(
self._channel_id, message.body, '', reply_to, properties=properties)
except Exception as e:
logger.error("Unhandled exception during echo message publishing", exc_info=e)
async def _connect_forever(self) -> None:
try:
while True:
try:
logger.info("Connecting to AMQP server")
await self._client.connection_open('localhost')
channel_open_result = await self._client.channel_open(self._channel_id)
await self._client.queue_declare(
self._channel_id,
queue=self._rpc_queue_name,
auto_delete=True
)
await self._client.basic_consume(
self._channel_id,
queue=self._rpc_queue_name
)
logger.info("Monitoring for network interruptions...")
await channel_open_result.close_reason
except aio.CancelledError:
raise
except aio_amqp.ConnectFailedError as e:
logger.error("Connect to AMQP server failed", exc_info=e)
except aio_amqp.ConnectionLostError as e:
logger.error("Connection lost", exc_info=e)
except aio_amqp.ConnectionClosedByServerError as e:
if e.reply_code == aio_amqp.REPLY_CODE.ACCESS_REFUSED:
logger.error("Access refused", exc_info=e)
else:
logger.error("Connection closed by server", exc_info=e)
except aio_amqp.ChannelClosedByServerError as e:
if self._client.is_connection_open():
await self._client.connection_close()
logger.error("Channel closed by server", exc_info=e)
except Exception as e:
await self._client.connection_close()
logger.error("Unhandled exception during connecting", exc_info=e)
raise
else:
logger.info("Connection closed")
return
logger.info("Reconnect after %d seconds" % self._reconnection_interval)
await aio.sleep(self._reconnection_interval)
finally:
if self._client.is_connection_open():
await self._client.connection_close()
if __name__ == '__main__':
logging.basicConfig(
level='DEBUG'
)
loop = aio.new_event_loop()
server = EchoRpcServer('rpc_queue', reconnection_interval=10, loop=loop)
try:
loop.run_forever()
except KeyboardInterrupt:
pass
finally:
loop.run_until_complete(server.close())
loop.run_until_complete(loop.shutdown_asyncgens())
loop.close()Copyright 2020 Not Just A Toy Corp.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.