Brad Fitzpatrick > Gearman > Gearman::Worker

Download:
Gearman-1.09.tar.gz

Dependencies

Annotate this POD

CPAN RT

New  20
Open  2
View/Report Bugs
Source   Latest Release: Gearman-1.12.002

NAME ^

Gearman::Worker - Worker for gearman distributed job system

SYNOPSIS ^

    use Gearman::Worker;
    my $worker = Gearman::Worker->new;
    $worker->job_servers('127.0.0.1');
    $worker->register_function($funcname => $subref);
    $worker->work while 1;

DESCRIPTION ^

Gearman::Worker is a worker class for the Gearman distributed job system, providing a framework for receiving and serving jobs from a Gearman server.

Callers instantiate a Gearman::Worker object, register a list of functions and capabilities that they can handle, then enter an event loop, waiting for the server to send jobs.

The worker can send a return value back to the server, which then gets sent back to the client that requested the job; or it can simply execute silently.

USAGE ^

Gearman::Worker->new(%options)

Creates a new Gearman::Worker object, and returns the object.

If %options is provided, initializes the new worker object with the settings in %options, which can contain:

$worker->job_servers(@servers)

Initializes the worker $worker with the list of job servers in @servers. @servers should contain a list of IP addresses, with optional port numbers. For example:

    $worker->job_servers('127.0.0.1', '192.168.1.100:7003');

If the port number is not provided, 7003 is used as the default.

Calling this method will do nothing in a worker that is running as a child process of a gearman server.

$worker->register_function($funcname, $subref)

$worker->register_function($funcname, $timeout, $subref)

Registers the function $funcname as being provided by the worker $worker, and advertises these capabilities to all of the job servers defined in this worker.

$subref must be a subroutine reference that will be invoked when the worker receives a request for this function. It will be passed a Gearman::Job object representing the job that has been received by the worker.

$timeout is an optional parameter specifying how long the jobserver will wait for your subroutine to give an answer. Exceeding this time will result in the jobserver reassigning the task and ignoring your result. This prevents a gimpy worker from ruining the 'user experience' in many situations.

The subroutine reference can return a return value, which will be sent back to the job server.

$client->prefix($prefix)

Sets the namespace / prefix for the function names. This is useful for sharing job servers between different applications or different instances of the same application (different development sandboxes for example).

The namespace is currently implemented as a simple tab separated concatentation of the prefix and the function name.

Gearman::Job->arg

Returns the scalar argument that the client sent to the job server.

Gearman::Job->set_status($numerator, $denominator)

Updates the status of the job (most likely, a long-running job) and sends it back to the job server. $numerator and $denominator should represent the percentage completion of the job.

Gearman::Job->work(%opts)

Do one job and returns (no value returned). You can pass "on_start" "on_complete" and "on_fail" callbacks in %opts.

WORKERS AS CHILD PROCESSES ^

Gearman workers can be run run as child processes of a parent process which embeds Gearman::Server. When such a parent process fork/execs a worker, it sets the environment variable GEARMAN_WORKER_USE_STDIO to true before launching the worker. If this variable is set to true, then the jobservers function and option for new() are ignored and the unix socket bound to STDIN/OUT are used instead as the IO path to the gearman server.

EXAMPLES ^

Summation

This is an example worker that receives a request to sum up a list of integers.

    use Gearman::Worker;
    use Storable qw( thaw );
    use List::Util qw( sum );
    my $worker = Gearman::Worker->new;
    $worker->job_servers('127.0.0.1');
    $worker->register_function(sum => sub { sum @{ thaw($_[0]->arg) } });
    $worker->work while 1;

See the Gearman::Client documentation for a sample client sending the sum job.

syntax highlighting: