NAME

Net::Gearman::Blobbed - Blob support for IO::Async Gearman client and worker

SYNOPSIS

# see Net::Gearman::Blobbed::Client
# see Net::Gearman::Blobbed::Worker

BACKGROUND

Gearman

Gearman is a job management system where one (or more) clients can request to a gearmand server that a job - consisting of a name and an opaque parameter octet stream - should be computed. Also to the gearmand server workers can connect and register their willingness to do such computations.

Idle workers take over such jobs, optionally report partial results or any progress and then either complete the jobs with results or fail with errors. The gearmand will pass on these results to the requesting client.

Net::Gearman

Net::Gearman is one implementation, but one based on the concepts of Futures. While the Net::Gearman::Worker will simply run a loop, fetching one job after the other, the Net::Gearman::Client will submit a job which immediately results in a Future object.

DESCRIPTION

This package uses Net::Gearman under the hood but adds a few features:

• Alternatively to sending one opaque parameter to the worker (via the job server, of course), you can use a parameter list as you would for a normal function. This parameter list will be JSON-encoded before sending off.

• As the Gearman protocol implementations pose a limit on the size of data you can send, in this job invocation you can add an URN together with the data. That URN points to a key/value store and to a specific location therein. Before sending the data itself, it is written to the store and only the URN is sent via the gearman protocol.

  On the worker you can resolve these URNs to retrieve the actual data.

  The same mechanism can be used when completed results are sent back to the client.

URNs

These special URIs are used to address both, the storage backend and a specific key therein where data should be stored or looked up. To avoid any confusion all URNs must be of the form

urn:x-technology:key

Examples are:

urn:x-file:aaa.txt     # for storing in local files
urn:x-memcache:aaa     # for Memcache
urn:x-s3:mybucket/aaa  # for S3

These also happen to be the technologies currently bundled with Net::Gearman::Blobbed. See these subclasses on how to attach them to a worker or the client.

INTERFACE

Variables

You should initialize a Log::Log4perl logger and pass it into the Net::Gearman::Blobbed package:

my $log = Log::Log4perl->get_logger("whatever");

use Net::Gearman::Blobbed;
$Net::Gearman::Blobbed::log = $log;

Logging is doublegood.

Methods

• resolve

  Once you retrieved - on the worker or on the client side - a list of parameters, this method replaces any URN references to the data with the data itself:

    my @args   = @{ decode_json( $job->arg )};        # get the list of arguments (possibly WITH URNs)
    my @params = $worker_or_client->resolve( @args ); # get the list of arguments (data, no URNs)
  

  If a URN cannot be resolved, then an exception will be raised.

  NOTE: When resolving, the data will remain at the store. That is intentional, as jobs might fail during computation and the Gearman server will task another server with the pending job. This implies that it is your responsibilty to purge the store with delete method (see below).

• delete

  This method takes a list of arguments (with and without URNs) and will try to delete any data to which these URNs point to:

    $worker_or_client->delete( @args );
  

• unresolve

  This method stores data under any provided URNs (yeah, probably not the most perfect name). So if you pass on

    my @args = $client_or_worker->unresolve( "some string",
                                             23             # some number
                                             'urn:x-memcache:some-key' => $some_data->freeze );
  

  then the frozen data will be saved into the configured Memcache store. The result list contains the original data, except those which have URNs provided. Here only the URN itself will be returned:

    @args: ( "some string", 23 'urn:x-memcache:some-key' )
  

SEE ALSO

• t/*.t test suites in this distribution
• Github
• Gearman Protocol

AUTHOR

Robert Barta, <rho at devc.at>

LICENSE AND COPYRIGHT

Copyright 2026 Robert Barta.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

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