Basic Rabbitmq Nack consumer program in python.

[Shafa]

Hi all,

I'm looking for a basic Rabbitmq Nack consumer program in python. So far, I have the basic producer program.

cli_ack.py:

import pika, socket

credentials = pika.PlainCredentials('xxxx', '1234')
hostname = socket.gethostname()
parameters = pika.ConnectionParameters(host=socket.gethostbyname(hostname), port=5672, virtual_host='/', credentials=credentials)

connection = pika.BlockingConnection(parameters)
channel = connection.channel()

msg_props = pika.BasicProperties()
msg_props.content_type = "text/plain"

channel.queue_declare(queue='hello')
if channel.basic_publish(exchange='', routing_key='hello', body='Hello World!', properties=msg_props):
    print ("Message Acknowledged")
else:
    print ("Message Lost")

print("[x] Sent 'Hello World!'")
connection.close()

ser_ack.py:

import pika, socket

credentials = pika.PlainCredentials('my_server', '1234')
hostname = socket.gethostname()
parameters = pika.ConnectionParameters(host=socket.gethostbyname(hostname), port=5672, virtual_host='/', credentials=credentials)

connection = pika.BlockingConnection(parameters)
channel = connection.channel()

channel.queue_declare(queue='hello')


def callback(ch, method, properties, body):
    print(" [x] Received %r" % body)


channel.basic_consume(queue='hello', on_message_callback=callback, auto_ack=False)

print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()


OUTPUT:
>python cli_ack.py
 Message Lost        # But it should be "Message Acknowledged"
 [x] Sent 'Hello World!'

>python ser_ack.py
 [*] Waiting for messages. To exit press CTRL+C
 [x] Received b'Hello World!'    # Message is received, but the ack is not sent.

What is the correct consumer program in python? Thank you.

[Luke Bakken]

Hello,

The return value of channel.basic_publish does not indicate if the publish succeeded or not.

I updated the documentation source 26 days ago -

https://github.com/pika/pika/blob/master/docs/examples/blocking_publish_mandatory.rst

I just triggered a build so that this page will be updated -

https://pika.readthedocs.io/en/latest/examples/blocking_delivery_confirmations.html

Thank you,

Luke

[Luke Bakken]

Also -

Please note that the definitive source of information is the source code itself:

https://github.com/pika/pika/blob/master/pika/adapters/blocking_connection.py#L2170-L2200

[Shafa]

Thank you. From the link, https://pika.readthedocs.io/en/latest/examples/blocking_delivery_confirmations.html

The output is the same, 

>python server.py

Message published could not be confirmed.

I still didn't get the desired output.

[Luke Bakken]

Hello,

I updated a different example. I've just updated the doc to which you linked, and started a build on readthedocs

As I noted before, you can use the source code itself to verify how a method works:

https://github.com/pika/pika/blob/master/pika/adapters/blocking_connection.py#L2170-L2200

Please read the in-line documentation above. You will see that the return value of the method does not indicate publish success.

Thanks -

Luke