在可读队列python中关闭连接

Question

When the microservice takes a message from RabbitMQ and the data is processed for a long time, and the connection is closed with the queue that is on the wiretap

Traceback (most recent call last):
  File "/home/saturn/Logic/MAIN_1.py", line 200, in <module>
    channel.start_consuming()
  File "/usr/local/lib/python3.5/dist-packages/pika/adapters/blocking_connection.py", line 1780, in start_consuming
    self.connection.process_data_events(time_limit=None)
  File "/usr/local/lib/python3.5/dist-packages/pika/adapters/blocking_connection.py", line 707, in process_data_events
    self._flush_output(common_terminator)
  File "/usr/local/lib/python3.5/dist-packages/pika/adapters/blocking_connection.py", line 474, in _flush_output
result.reason_text)
pika.exceptions.ConnectionClosed: (-1, "ConnectionResetError(104, 'Connection reset by peer')") 

Now task processing near 5 minutes. Main code like -

credentials = pika.PlainCredentials(username='NAME',password='PASSWORD')
ConnParr = pika.ConnectionParameters(host='HOST', credentials=credentials)
connection = pika.BlockingConnection(ConnParr)
channel = connection.channel()

def callback(ch, method, properties, body):
    in_data = json.loads(body.decode('utf-8'))
    main(in_data)
    ch.basic_ack(delivery_tag=method.delivery_tag)

def main(in_data):
    time.sleep(300)

channel.queue_declare(queue=IN_QUEUE)
channel.basic_qos(prefetch_count=1)
channel.basic_consume(callback, queue=IN_QUEUE)
channel.start_consuming()     

Answer 1

This is happening because the time.sleep call blocks your main thread and prevents Pika from sending and receiving heartbeat messages from RabbitMQ. You have a couple ways to fix this:

• Upgrade to Pika 0.12.0 , run your main method in a separate thread, and use add_callback_threadsafe in that thread to call basic_ack on the channel docs .

• Use the asynchronous consumer example as a starting point for your code.

The important part to remember is that you can't block Pika's internal event loops and expect the connection to stay alive. If you need further assistance, Pika's maintainers (me among others) monitor the rabbitmq-users and pika-python mailing lists for questions.