/ 
Crixa-0.13
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/ Crixa

NAME

Crixa - A Cleaner API for Net::AMQP::RabbitMQ

VERSION

version 0.13

SYNOPSIS

use Crixa;

my $mq       = Crixa->connect( host => 'localhost' );
my $channel  = $mq->new_channel;
my $exchange = $channel->exchange( name => 'hello' );

$exchange->publish('Hello World');

my $queue = $exchange->queue( name => 'hello' );

$queue->handle_message( sub { say $_->body } );

DESCRIPTION

All the world will be your enemy, Prince of a Thousand enemies. And when
they catch you, they will kill you. But first they must catch you; digger,
listener, runner, Prince with the swift warning. Be cunning, and full of
tricks, and your people will never be destroyed. -- Richard Adams

This module provides a more natural API over Net::AMQP::RabbitMQ, with separate objects for channels, exchanges, and queues.

WARNING

Crixa is still in development and the API may change in the future!

METHODS

This class provides the following methods:

Crixa->connect(...)

Creates a new connection to a RabbitMQ server. It takes a hash or hashref of named parameters.

host => $hostname

The hostname to connect to. Required.

port => $post

An optional port.

user => $user

An optional username.

password => $password

An optional password.

mq => $mq

This is an optional parameter which can contain an object which implements the Net::AMQP::RabbitMQ interface.

Normally this will be created as needed but you can pass a Test::Net::RabbitMQ object instead so you can write tests for code that uses Crixa without actually having a rabbitmq server running.

Note that Test::Net::RabbitMQ does not (as of version 0.10) implement the entire Net::AMQP::RabbitMQ interface so some Crixa methods may blow up with Test::Net::RabbitMQ.

See the section on "MOCKING" for more details.

$crixa->new_channel

Returns a new Crixa::Channel object.

You can use the channel to create exchanges and queues.

$crixa->disconnect

Disconnect from the server. This is called implicitly by DEMOLISH so normally there should be no need to do this explicitly.

$crixa->host

Returns the port passed to the constructor, if nay.

$crixa->user

Returns the user passed to the constructor, if any.

$crixa->password

Returns the password passed to the constructor, if any.

$crixa->is_connected

This returns true if the underlying mq object thinks it is connected.

MOCKING

If you are testing code that uses Crixa, you may want to mock out the use of an actual rabbitmq server with something that is a little simpler to test. In that case, you can pass a Test::Net::RabbitMQ object to the Crixa->connect method:

my $test_mq = Test::Net::RabbitMQ->new;
my $crixa   = Crixa->connect(
    host => 'irrelevant',
    mq   => $test_mq,
);

Note that if you are publishing and consuming messages, this all must happen in a single process and a single Test::Net::RabbitMQ object in order for this mocking to work.

If the code that publishes messages makes a separate Crixa object from the one you use to test those messages, you need to be careful to share the same Test::Net::RabbitMQ object. Also, since the Crixa object calls its disconnect() method when it goes out of scope, you may need to reconnect the Test::Net::RabbitMQ object or it will die when you call methods on it.

Here's an example:

my $test_mq = Test::Net::RabbitMQ->new;
test_messages($test_mq) :;

sub test_messages {
    my $mq    = shift;
    my $crixa = Crixa->connect(
        host => 'irrelevant',
        mq   => $test_mq,
    );

    publish($test_mq);

    # This will die!
    my @messages = $crixa->channel->queue(...)->check_for_messages;
}

sub publish {
    my $mq    = shift;
    my $crixa = Crixa->connect(
        host => 'irrelevant',
        mq   => $test_mq,
    );

    # publish some messages

    # When the sub exits the $crixa object calls disconnect() on itself.
}

We can fix this by adding an extra "safety" call to connect the $test_mq object in the test_messages() sub:

sub test_messages {
    my $mq    = shift;
    my $crixa = Crixa->connect(
        host => 'irrelevant',
        mq   => $test_mq,
    );

    publish($test_mq);

    $test_mq->connect unless $test_mq->connected;

    # This will die!
    my @messages = $crixa->channel->queue(...)->check_for_messages;
}

Of course, this is a very artificial example, but in real code you may come across this problem.

SUPPORT

Please report all issues with this code using the GitHub issue tracker at https://github.com/Tamarou/Crixa/issues.

SEE ALSO

This module uses Net::AMQP::RabbitMQ under the hood, though it does not expose everything provided by its API.

The best documentation we've found on RabbitMQ (and AMQP) concepts is the Bunny documentation at http://rubybunny.info/articles/guides.html. We strongly recommend browsing this to get a better understanding of how RabbitMQ works, what different options for exchanges, queues, and messages mean, and more.

AUTHORS

  • Chris Prather <chris@prather.org>

  • Dave Rolsky <autarch@urth.org>

CONTRIBUTORS

  • Gregory Oschwald <goschwald@maxmind.com>

  • Gregory Oschwald <oschwald@gmail.com>

  • Ran Eilam <ran.eilam@gmail.com>

  • Torsten Raudssus <torsten@raudss.us>

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 - 2015 by Chris Prather.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.