PyRMQ 1.5.1

Python with RabbitMQ—simplified so you won't have to.

PyRMQ

Python with RabbitMQ—simplified so you won't have to.

Features

Stop worrying about boilerplating and implementing retry logic for your queues. PyRMQ already does it for you.

• Use out-of-the-box Consumer and Publisher classes created from pika for your projects and tests.
• Custom DLX-DLK-based retry logic for message consumption.
• Message priorities
• Works with Python 3.
• Production ready

Getting Started

Installation

PyRMQ is available at PyPi.

pip install pyrmq

Usage

Publishing

Just instantiate the feature you want with their respective settings. PyRMQ already works out of the box with RabbitMQ's default initialization settings.

from pyrmq import Publisher
publisher = Publisher(
    exchange_name="exchange_name",
    queue_name="queue_name",
    routing_key="routing_key",
)
publisher.publish({"pyrmq": "My first message"})

Publish message with priorities

To enable prioritization of messages, instantiate your queue with the queue argument x-max-priority. It takes an integer that sets the number of possible priority values with a higher number commanding more priority. Then, simply publish your message with the priority argument specified. Any number higher than the set max priority is floored or considered the same. Read more about message priorities here.

from pyrmq import Publisher
publisher = Publisher(
    exchange_name="exchange_name",
    queue_name="queue_name",
    routing_key="routing_key",
    queue_args={"x-max-priority": 3},
)
publisher.publish({"pyrmq": "My first message"}, priority=1)

:warning: Warning
Adding arguments on an existing queue is not possible. If you wish to add queue arguments, you will need to either
delete the existing queue then recreate the queue with arguments or simply make a new queue with the arguments.

Consuming

Instantiating a Consumer automatically starts it in its own thread making it non-blocking by default. When run after the code from before, you should be able to receive the published data.

from pyrmq import Consumer

def callback(data):
    print(f"Received {data}!")

consumer = Consumer(
    exchange_name="exchange_name",
    queue_name="queue_name",
    routing_key="routing_key",
    callback=callback
)
consumer.start()

DLX-DLK Retry Logic

What if you wanted to retry a failure on a consumed message? PyRMQ offers a custom solution that keeps your message in queues while retrying in an exponential backoff fashion.

This approach uses dead letter exchanges and queues to republish a message to your original queue once it has expired. PyRMQ creates this "retry" queue for you with the default naming convention of appending your original queue with .retry.

from pyrmq import Consumer

def callback(data):
    print(f"Received {data}!")
    raise Exception

consumer = Consumer(
    exchange_name="exchange_name",
    queue_name="queue_name",
    routing_key="routing_key",
    callback=callback,
    is_dlk_retry_enabled=True,
)
consumer.start()

This will start a loop of passing your message between the original queue and the retry queue until it reaches the default number of max_retries.

Using other exchange types

You can use another exchange type just by simply specifying it in the Publisher class. The default is direct.

from pyrmq import Publisher

queue_args = {"routing.sample": "sample", "x-match": "all"}

publisher = Publisher(
    exchange_name="exchange_name",
    exchange_type="headers",
    queue_args=queue_args
)

message_properties = {"headers": {"routing.sample": "sample"}}
publisher.publish({"pyrmq": "My first message"}, message_properties=message_properties)

This is an example of how to publish to a headers exchange that will get routed based on its headers.

Documentation

Visit https://pyrmq.readthedocs.io for the most up-to-date documentation.

Testing

For development, just run:

pytest

To test for all the supported Python versions:

pip install tox
tox

To test for a specific Python version:

tox -e py38