use 5.008001;
use strict;
use warnings;
package Dancer2::Plugin::Queue;
# ABSTRACT: Dancer2 plugin for message queue abstractions
our $VERSION = '0.002'; # VERSION
use Dancer2::Plugin;
use Class::Load qw/try_load_class/;
my %queues;
my $conf;
register queue => sub {
my ( $dsl, $name ) = plugin_args(@_);
$conf ||= plugin_setting();
# if name not specified, DWIM or use 'default'
if ( not defined $name ) {
if ( keys %$conf == 1 ) {
($name) = keys %$conf;
}
elsif ( exists $conf->{default} ) {
$name = "default";
}
else {
die "Can't determine a default queue name";
}
}
# return cached object if already created
return $queues{$name} if defined $queues{$name};
# otherwise, instantiate the object from config settings
my $queue_conf = $conf->{$name}
or die "No configuration for queue '$name'";
my $class = $queue_conf->{class}
or die "No class specified for queue '$name'";
$class = "Dancer2::Plugin::Queue::$class";
try_load_class($class)
or die "Queue class '$class' could not be loaded";
$class->can('DOES') && $class->DOES("Dancer2::Plugin::Queue::Role::Queue")
or die "Queue class '$class' does not implement the expected role";
my $object = eval { $class->new( $queue_conf->{options} || {} ) }
or die "Could not create $class object: $@";
return $queues{$name} = $object;
};
register_plugin for_versions => [2];
1;
# vim: ts=4 sts=4 sw=4 et:
__END__
=pod
=head1 NAME
Dancer2::Plugin::Queue - Dancer2 plugin for message queue abstractions
=head1 VERSION
version 0.002
=head1 SYNOPSIS
# in config.yml
plugins:
Queue:
default:
class: Array
options:
name: not_a_real_queue
# in your app
use Dancer2::Plugin::Queue;
post '/add_fortune' => sub {
# assume a 'fortune' parameter submitted
queue->add_msg( params->{fortune} );
# ...
};
get '/tell_fortune' => sub {
my ($msg, $body) = queue->get_msg;
queue->remove_msg( $msg );
return "Your fortune: $body";
};
=head1 DESCRIPTION
This module provides a generic interface to a message queue. Message queue
implementations must implement the L<Dancer2::Plugin::Queue::Role::Queue> role,
which defines the interface to abstract the specifics of the backend.
=for Pod::Coverage method_names_here
=head1 CONFIGURATION
Queue objects are defined by a C<< NAME => HASHREF >> pair. The hash reference
must contain a 'class' key, whose value is a class name suffix that will be
appended to C<Dancer2::Plugin::Queue::>. The resulting class will be loaded on
demand. If the hash reference contains an 'options' key, its value will be
passed to the constructor when the queue object is created.
=head1 USAGE
=head2 queue
queue;
queue($name);
This function returns a C<Dancer2::Plugin::Queue::*> object. If no C<$name> is
provided, it attempts to return a default object. If there is only a single
queue defined, it will be used as the default. If there is more than one, a
queue called 'default' will be the default. If there are more than one and
none are named 'default', an error will be thrown.
=head2 queue->add_msg
queue->add_msg( $data );
Adds C<$data> to the queue. It is up to the plugin implementation (or backend)
to serialize or otherwise modify C<$data>.
=head2 queue->get_msg
( $msg, $data ) = queue->get_msg;
Dequeues a message from the queue. C<$msg> will be either a 'raw' message object
from the backend or else an identifier that can be used with C<remove_msg>.
C<$data> should ideally be the same as the enqueued C<$data>, subject to any
round-trip limitations of the backend.
=head2 queue->remove_msg
queue->remove_msg( $msg );
Removes a message permanently from the queue (if not already done by C<get_msg>).
Some message queue implementations require handled messages to be manually
removed from the queue or else the message will time-out and be available
again.
This method should always be called after a message has been handled in case
the backend requires such cleanup. For implementations that do not have
message durability, this method may do nothing.
=for :stopwords cpan testmatrix url annocpan anno bugtracker rt cpants kwalitee diff irc mailto metadata placeholders metacpan
=head1 SUPPORT
=head2 Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker
at L<https://github.com/dagolden/dancer2-plugin-queue/issues>.
You will be notified automatically of any progress on your issue.
=head2 Source Code
This is open source software. The code repository is available for
public review and contribution under the terms of the license.
L<https://github.com/dagolden/dancer2-plugin-queue>
git clone git://github.com/dagolden/dancer2-plugin-queue.git
=head1 AUTHOR
David Golden <dagolden@cpan.org>
=head1 COPYRIGHT AND LICENSE
This software is Copyright (c) 2012 by David Golden.
This is free software, licensed under:
The Apache License, Version 2.0, January 2004
=cut