NAME¶
TheSchwartz::Worker - superclass for defining task behavior
SYNOPSIS¶
package MyWorker;
use base qw( TheSchwartz::Worker );
sub work {
my $class = shift;
my TheSchwartz::Job $job = shift;
print "Workin' hard or hardly workin'? Hyuk!!\n";
$job->completed();
}
package main;
my $client = TheSchwartz->new( databases => $DATABASE_INFO );
$client->can_do('MyWorker');
$client->work();
DESCRIPTION¶
TheSchwartz::Worker objects are the salt of the reliable job queuing
earth. The behavior required to perform posted jobs are defined in subclasses
of
TheSchwartz::Worker. These subclasses are named for the ability
required of a "TheSchwartz" client to do the job, so that the
clients can dispatch automatically to the approprate worker routine.
Because jobs can be performed by any machine running code for capable worker
classes, "TheSchwartz::Worker"s are generally stateless. All mutable
state is stored in the "TheSchwartz::Job" objects. This means all
"TheSchwartz::Worker" methods are
class methods, and
"TheSchwartz::Worker" classes are generally never instantiated.
SUBCLASSING¶
Define and customize how a job is performed by overriding these methods in your
subclass:
"$class->work( $job )"¶
Performs the job that required ability $class. Override this method to define
how to do the job you're defining.
Note that will need to call "$job->completed()" or
"$job->failed()" as appropriate to indicate success or failure.
See TheSchwartz::Job.
"$class->max_retries( $job )"¶
Returns the number of times workers should attempt the given job. After this
many tries, the job is marked as completed with errors (that is, a
"TheSchwartz::ExitStatus" is recorded for it) and removed from the
queue. By default, returns 0.
"$class->retry_delay( $num_failures )"¶
Returns the number of seconds after a failure workers should wait until
reattempting a job that has already failed $num_failures times. By default,
returns 0.
"$class->keep_exit_status_for()"¶
Returns the number of seconds to allow a "TheSchwartz::ExitStatus"
record for a job performed by this worker class to exist. By default, returns
0.
"$class->grab_for()"¶
Returns the number of seconds workers of this class will claim a grabbed a job.
That is, returns the length of the
timeout after which other workers
will decide a worker that claimed a job has crashed or faulted without marking
the job failed. Jobs that are marked as failed by a worker are also marked for
immediate retry after a delay indicated by "retry_delay()".
USAGE¶
"$class->grab_job( $client )"¶
Finds and claims a job for workers with ability $class, using
"TheSchwartz" client $client. This job can then be passed to
"work()" or "work_safely()" to perform it.
"$class->work_safely( $job )"¶
Performs the job associated with the worker's class name. If an error is thrown
while doing the job, the job is appropriately marked as failed, unlike when
calling "work()" directly.