easyrabbit 0.0.3
Easy utilities for common RabbitMQ tasks
License: MIT

easyrabbit
==========

|Coverage Status| |Build Status| |Doc Status|

Actually easy RabbitMQ utilities for common tasks. Hides the
complexities of complete control packages like ``pika`` by wrapping
common use cases in minimalistic wrappers.

Installation
============

You can install directly from Pypi::

    pip install easyrabbit

or from git using pip::

    pip install git+https://github.com/scnerd/easyrabbit

Usage
=====

Simple routing
--------------

Reader
~~~~~~

``RoutingReader`` provides a fully asynchronous way to read from an
exchange via a queue bound with a routing key. It launches a subprocess
to free the calling program from being responsible for its computational
overhead; within its own process, it uses ``pika``'s asynchronous
connection, enabling the highest possible performance client. The API
exposed mimics a simple queue, if, after all, what you really want is to
use a RabbitMQ queue as if it were a Python queue.

.. code:: python

    with RoutingReader(url, exchange, queue_name, routing_key) as reader:
        for msg in reader:
            print("Received the following message: {}".format(msg))

If the reader is needed persistently, you can also launch and terminate
it yourself:

.. code:: python

    reader = RoutingReader(url, exchange, queue_name, routing_key)
    reader.start()
    # Do things with the reader
    reader.close()

Note that even though the reader is asynchronous, you don't need to wait
for it to be ready before using it. All calls hang on the process pipe
that sends data from the client process to your parent code. If you want
to make sure that the connection is fully established before using it,
however, you can use ``wait_till_ready``:

.. code:: python

    reader = RoutingReader(url, exchange, queue_name, routing_key)
    reader.start()
    try:
        reader.wait_till_ready(timeout=5)
    except TimeoutError:
        raise RuntimeError("RabbitMQ reader took more than 5 seconds to launch")

While ``reader.get`` is blocking, a non-blocking equivalent is
``reader.get_nowait``, or your code can explicitly check that a value is
available first using ``not reader.empty()``. Iterating over ``reader``
just repeatedly calls ``get``, and hence is blocking and will only end
when the reader is closed. Use ``reader.getall_nowait()`` to obtain all
values currently in the queue.

All result objects are byte arrays.

Writing
~~~~~~~

The analogous utility for writing is ``RoutingWriter``, which provides a
nearly identical interface for writing messages to RabbitMQ

.. code:: python

    with RoutingWriter(url, exchange, routing_key) as writer:
        for msg in msgs:
            writer.put(msg)

``RoutingWriter`` exposes much the same API as ``RoutingReader``, except
of course exposing ``put`` instead of ``get``.

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