עידו פרלמוטר (Ido Perlmuter)

NAME

McBain::WithGearmanXS - Load a McBain API as a Gearman worker

VERSION

version 1.001000

SYNOPSIS

        # write your API as you normally would, and create
        # a simple start-up script:

        #!/usr/bin/perl -w

        BEGIN { $ENV{MCBAIN_WITH} = 'WithGearmanXS'; }

        use warnings;
        use strict;
        use MyAPI;

        MyAPI->work('localhost', 4730);

DESCRIPTION

McBain::WithGearmanXS turns your McBain API into a Gearman worker, making it easy to consume your APIs with Gearman clients.

When your API is loaded, this module will traverse its routes, and create a queue for each methods found. So, for example, if your API looks like this...

        package MyAPI;

        use McBain;

        get '/multiply' => (
                ...
        );

        post '/divide' => (
                ...
        );

...then the following queues will be created:

        GET:/multiply
        POST:/divide

The workers created receive payloads in JSON format, and convert them into the hash-refs your API's methods expect to receive. Results are sent back to the clients in JSON as well. Note that if an API method does not return a hash-ref, this runner module will automatically turn it into a hash-ref to ensure that conversion into JSON will be possible. The created hash-ref will have one key - holding the method's name, with whatever was returned from the method as its value. For example, if method GET:/divide in topic /math returns an integer (say 7), then the client will get the JSON { "GET:/math/divide": 7 }.

CAVEATS

There are some disadvantages to using this runner:

  • Since a queue is created for every route and method in the API, McBain cannot intercept calls to routes that do not exist.

  • You can't use regular expressions when defining queues. Well, you can, but they won't work.

  • Gearman provides no way of providing a detailed error message when jobs fail, therefore all McBain can do is indicate that the job has failed and no more.

The first two I hope to overcome in a next version, or even a different runner, by creating just one queue that simply forwards the requests to McBain.

METHODS EXPORTED TO YOUR API

work( [ $host, $port ] )

Connects the Gearman worker created by the module to the Gearman server running at the host and port provided. If none are provided, localhost and 4730 are used, respectively.

The method never returns, so that the worker listens for jobs continuously.

METHODS REQUIRED BY MCBAIN

This runner module implements the following methods required by McBain:

init( )

Creates the "work( $host, $port )" method for the root topic of the API.

generate_env( $job )

Receives the Gearman::XS::Job object and creates McBain's standard env hash-ref from it.

generate_res( $env, $res )

Converts the result from an API method in JSON. Read the discussion under "DESCRIPTION" for more info.

handle_exception( $err, $job )

Simply calls $job->send_fail to return a job failed status to the client.

CONFIGURATION AND ENVIRONMENT

No configuration files are required. To tell McBain to use this runner module, the MCBAIN_WITH environment variable must be set to WithGearmanXS. See the "SYNOPSIS" for an example.

DEPENDENCIES

McBain::WithGearmanXS depends on the following CPAN modules:

INCOMPATIBILITIES WITH OTHER MODULES

None reported.

BUGS AND LIMITATIONS

Please report any bugs or feature requests to bug-McBain-WithGearmanXS@rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=McBain-WithGearmanXS.

SUPPORT

You can find documentation for this module with the perldoc command.

        perldoc McBain::WithGearmanXS

You can also look for information at:

AUTHOR

Ido Perlmuter <ido@ido50.net>

LICENSE AND COPYRIGHT

Copyright (c) 2013, Ido Perlmuter ido@ido50.net.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either version 5.8.1 or any later version. See perlartistic and perlgpl.

The full text of the license can be found in the LICENSE file included with this module.

DISCLAIMER OF WARRANTY

BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.




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