Random connection errors with aio_pika after 2 days of running - python-3.x

Question

I have asyncio script which connects to rabbitmq with aio_pika library every 40 seconds and checks if there are any messages and prints them out which then repeats forever. However, usually, after 2 or so days of running, I will start receiving endless connection exception errors which will only be solved by restarting the script. Perhaps there are some obvious mistakes in the logic of my asyncio script which I am missing?
#!/usr/bin/python3
import time
import async_timeout
import asyncio
import aio_pika
async def got_message(message: aio_pika.IncomingMessage):
with message.process():
print(message.body.decode())
async def main(loop):
try:
with async_timeout.timeout(10):
connection = await aio_pika.connect_robust(
host='#',
virtualhost='#',
login='#',
password='#',
port=5671,
loop=loop,
ssl=True
)
channel = await connection.channel()
await channel.set_qos(prefetch_count=100)
queue_name='mm_message'
queue = await channel.declare_queue(auto_delete=False, name=queue_name)
routing_key='mm_msg'
await queue.bind("amq.topic", routing_key)
que_len = queue.declaration_result.message_count
if(que_len > 0):
await queue.consume(got_message)
except:
print("connection problems..")
if __name__ == "__main__":
loop = asyncio.get_event_loop()
while(True):
time.sleep(40)
loop.run_until_complete(main(loop))
This is the error I endlessly receive after some time:
Traceback (most recent call last):
File "/usr/lib/python3.5/asyncio/events.py", line 125, in _run
self._callback(*self._args)
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/adapters/base_connection.py", line 364, in _handle_events
self._handle_read()
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/adapters/base_connection.py", line 415, in _handle_read
self._on_data_available(data)
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1347, in _on_data_available
self._process_frame(frame_value)
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1414, in _process_frame
if self._process_callbacks(frame_value):
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1384, in _process_callbacks
frame_value) # Args
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/callback.py", line 60, in wrapper
return function(*tuple(args), **kwargs)
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/callback.py", line 92, in wrapper
return function(*args, **kwargs)
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/callback.py", line 236, in process
callback(*args, **keywords)
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1332, in _on_connection_tune
self._send_connection_open()
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1517, in _send_connection_open
self._on_connection_open, [spec.Connection.OpenOk])
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1501, in _rpc
self._send_method(channel_number, method_frame)
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1569, in _send_method
self._send_frame(frame.Method(channel_number, method_frame))
File "/usr/local/lib/python3.5/dist-packages/aio_pika/pika/connection.py", line 1548, in _send_frame
raise exceptions.ConnectionClosed
aio_pika.pika.exceptions.ConnectionClosed

Answer 1

except:
print("connection problems..")
This will catch service Exceptions like KeyboardInterrupt, SystemExit. You should never do such thing if you're not going to reraise exception. At very lest you should write:
except Exception:
print("connection problems..")
However in context of asyncio snippet above will break mechanism of cancellation. To avoid it as explained here you should write:
try:
await operation
except asyncio.CancelledError:
raise
except Exception:
log.log('an error has occurred')
Not less important is to understand that connection should not only be opened, but closed also (regardless of what happened between opening and closing). To achieve that people usually use context managers (and in asyncio - asynchronous context managers).
aio_pika doesn't seem to be exception. As example shows you should use async with when dealing with connection:
connection = await aio_pika.connect_robust(
"amqp://guest:guest#127.0.0.1/", loop=loop
)
async with connection:
# ...