| Gearman::Driver::Worker - Base class for workers |
Gearman::Driver::Worker - Base class for workers
package My::Worker;
use base qw(Gearman::Driver::Worker);
use Moose;
sub begin {
my ( $self, $job, $workload ) = @_;
# called before each job
}
sub prefix {
# default: return ref(shift) . '::';
return join '_', split /::/, __PACKAGE__;
}
sub do_something : Job : MinProcesses(2) : MaxProcesses(15) {
my ( $self, $job, $workload ) = @_;
# $job => Gearman::XS::Job instance
}
sub end {
my ( $self, $job, $workload ) = @_;
# called after each job
}
sub spread_work : Job {
my ( $self, $job, $workload ) = @_;
my $gc = Gearman::XS::Client->new;
$gc->add_servers( $self->server );
$gc->do_background( 'some_job_1' => $job->workload );
$gc->do_background( 'some_job_2' => $job->workload );
$gc->do_background( 'some_job_3' => $job->workload );
$gc->do_background( 'some_job_4' => $job->workload );
$gc->do_background( 'some_job_5' => $job->workload );
}
1;
the Gearman::Driver manpage connects to the server passed to its constructor. This value is also stored in this class. This can be useful if a job uses the Gearman::XS::Client manpage to add another job. See 'spread_work' method in SYNOPSIS above.
This will register the method with gearmand.
Minimum number of processes working parallel on this job/method.
Maximum number of processes working parallel on this job/method.
This will automatically look for a method encode in this object
which has to be defined in the subclass. It will call the encode
method passing the return value from the job method. The return
value of the encode method will be returned to the Gearman
client. This is useful to serialize Perl datastructures to JSON
before sending them back to the client.
sub do_some_job : Job : Encode : Decode {
my ( $self, $job, $workload ) = @_;
return { message => 'OK', status => 1 };
# calls 'encode' and returns JSON string: {"status":1,"message":"OK"}
}
sub custom_encoder : Job : Encode(enc_yaml) : Decode(dec_yaml) {
my ( $self, $job, $workload ) = @_;
return { message => 'OK', status => 1 };
# calls 'enc_yaml' and returns YAML string:
# ---
# message: OK
# status: 1
}
sub encode {
my ( $self, $result ) = @_;
return JSON::XS::encode_json($result);
}
sub decode {
my ( $self, $workload ) = @_;
return JSON::XS::decode_json($workload);
}
sub enc_yaml {
my ( $self, $result ) = @_;
return YAML::XS::Dump($result);
}
sub dec_yaml {
my ( $self, $workload ) = @_;
return YAML::XS::Load($workload);
}
This will automatically look for a method decode in this object
which has to be defined in the subclass. It will call the decode
method passing the workload value ($job->workload). The return
value of the decode method will be passed as 3rd argument to the
job method. This is useful to deserialize JSON workload to Perl
datastructures for example. If this attribute is not set,
$job->workload and $workload is the same.
Example, workload is this string: {"status":1,"message":"OK"}
sub decode {
my ( $self, $workload ) = @_;
return JSON::XS::decode_json($workload);
}
sub job1 : Job {
my ( $self, $job, $workload ) = @_;
# $workload eq $job->workload eq '{"status":1,"message":"OK"}'
}
sub job2 : Job : Decode {
my ( $self, $job, $workload ) = @_;
# $workload ne $job->workload
# $job->workload eq '{"status":1,"message":"OK"}'
# $workload = { status => 1, message => 'OK' }
}
Having the same method name in two different classes would result
in a clash when registering it with gearmand. To avoid this,
all jobs are registered with the full package and method name
(e.g. My::Worker::some_job). The default prefix is
ref(shift . '::'), but this can be changed by overriding the
prefix method in the subclass, see SYNOPSIS above.
This method is called before a job method is called. In this base class this methods just does nothing, but can be overridden in a subclass.
The parameters are the same as in the job method:
This method is called after a job method has been called. In this base class this methods just does nothing, but can be overridden in a subclass.
The parameters are the same as in the job method:
$self
$job
If this method is overridden in the subclass it will change the process name after a job has been forked.
The following parameters are passed to this method:
Example:
sub process_name {
my ( $self, $orig, $job_name ) = @_;
return "$orig ($job_name)";
}
This may look like:
plu 2034 0.0 1.7 22392 17948 pts/2 S 21:17 0:00 ./examples/test.pl (GDExamples::Sleeper::ZzZzZzzz)
plu 2035 0.0 1.7 22392 17944 pts/2 S 21:17 0:00 ./examples/test.pl (GDExamples::Sleeper::ZzZzZzzz)
plu 2036 0.0 1.7 22392 17948 pts/2 S 21:17 0:00 ./examples/test.pl (GDExamples::Sleeper::ZzZzZzzz)
plu 2037 0.0 1.7 22392 17956 pts/2 S 21:17 0:00 ./examples/test.pl (GDExamples::Sleeper::long_running_ZzZzZzzz)
If this method is overridden in the subclass it will change all attributes of your job methods. It must return a reference to a hash containing valid attribute keys. E.g.:
sub override_attributes {
return {
MinProcesses => 1,
MaxProcesses => 1,
}
}
sub job1 : Job : MinProcesses(10) : MaxProcesses(20) {
my ( $self, $job, $workload ) = @_;
# This will get MinProcesses(1) MaxProcesses(1) from override_attributes
}
If this method is overridden in the subclass it can supply default attributes which are added to all job methods. This is useful if you want to Encode/Decode all your jobs:
sub default_attributes {
return {
Encode => 'encode',
Decode => 'decode',
}
}
sub decode {
my ( $self, $workload ) = @_;
return JSON::XS::decode_json($workload);
}
sub encode {
my ( $self, $result ) = @_;
return JSON::XS::encode_json($result);
}
sub job1 : Job {
my ( $self, $job, $workload ) = @_;
}
no Moose;
__PACKAGE__->meta->make_immutable;
Johannes Plunien <plu@cpan.org>
Copyright 2009 by Johannes Plunien
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
| Gearman::Driver::Worker - Base class for workers |