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Schedule-Pluggable-0.0.6
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/ Schedule::Pluggable

NAME

Schedule::Pluggable - Flexible Perl Process Scheduler

SYNOPSIS

 EXAMPLE #1:    Simple Run in Series
    use Schedule::Pluggable;
    my $p = Schedule::Pluggable->new;
    my $status = $p->run_in_series( [ qw/command1 command2 command3/ ] );

 EXAMPLE #2:    Simple Run in Parallel
    use Schedule::Pluggable;
    my $p = Schedule::Pluggable->new;
    my $status = $p->run_in_parallel( [ qw/command1 command2 command3/ ] );


 EXAMPLE #3:    With Job  Names
    use Schedule::Pluggable;
    my $p = Schedule::Pluggable->new;
    my @jobs = (
                { name => "FirstJob", command => "somescript.sh" },
                { name => "2nd Job", command => sub { do_something; } },
                );
    my $status = $p->run_schedule( \@jobs );

  EXAMPLE #4:    With Prerequsites
    use Schedule::Pluggable;
    my $p = Schedule::Pluggable->new;
    my $jobs = [ { name => "FirstJob",
                   command => "somescript.sh" },
                 { name => "SecondJob",
                   command => sub { do_something; },
                   prerequisites => [qw/FirstJob/] },
               ];
    my $status = $p->run_schedule( $jobs );

  EXAMPLE #5:    Same as #4 but with dependencies
    use Schedule::Pluggable;
    my $p = Schedule::Pluggable->new;
    my $jobs = [ { name => "FirstJob",
                   command => "somescript.sh",
                   dependencies => [qw/SecondJob/] },
                 { name => "SecondJob",
                   command => sub { do_something; } },
               ];
    my $status = $ps->run_schedule( $jobs );

  EXAMPLE #5:  With Groups 
    use Schedule::Pluggable;
    my $p = Schedule::Pluggable->new;
    my $jobs = ( { name => "one", command => "one.sh", dependencies => [ qw/Reports/ ] }, 
                 { name => "two", command => "two.pl" }, groups => [ qw/Reports/] },             
                 { name => "three", command => "three.pl" }, groups => [ qw/Reports/] },
                 { name => "four", command => "four.ksh" }, prerequisites => [ qw/Reports/] },
                );
    my $status = $p->run_schedule( $jobs );

  EXAMPLE #6: Getting the config from an XML file

    use Schedule::Pluggable (JobsConfig => 'JobsFromXML');
    my $p = Schedule::Pluggable->new;
    my $status = $p->run_schedule({XMLFile => 'path to xml file'});

    XMlFile in following format :-
    <?xml version="1.0"?>
    <Jobs>
        <Job name='Job1' command='succeed.pl'>
            <params>3</params>
            <dependencies>second</dependencies>
        </Job>
        <Job name='Job2' command='fail.pl'>
            <params>3</params>
            <group>second</group>
        </Job>
        ...
    <Jobs>

DESCRIPTION

Schedule::Pluggable is a perl module which provides a simple but powerful way of running processes in a controlled way. In true perl fashion it makes simple things easy and complicated things possible. It also uses a system of plugins so you can change it's behaviour to suit your requirements by supplying your own plugins. For most cases the default plugins will suffice however.

OPTIONS

You can override the default behaviour of Schedule::Pluggable by supplying options with the use statement in for form of a hash

i.e.

use Schedule::Pluggable ( Option => "value' );

The Following options are supported :-

JobsConfig

Specifies which plugin to use to provide the job configuration - defaults to JobsFromData which expects you to supply the job configuration in an array

Each plugin is expected to

e.g.

use Schedule::Pluggable ( JobsConfig => 'JobsFromSomeWhere' );

Currently the available values are :-

JobsFromArray

The default which activates the role 'Schedule::Pluggable::Plugin::JobsFromData' which as the name suggests expects the job configuration to be be supplied as an reference to an array of jobs to run.

JobsFromXML

Activates plugin Schedule::Pluggable::Plugin::JobsFromXML which obtains the jobs configuration from an XML file

This enables you to specify a different source for the config by supplying an appropriate plugin for it - see writing Plugins for details

EventHandler

Controls what happens when an event happens like a jobs starting a job failing e.t.c Defaults to DefaultEventHandler which is a plugin Schedule::Pluggable::Plugin::DefaultEventHandler Here is what is passed depending on event type

JobName - Always passed
Command - Always passed
Stdout - Passed on JobStdout and JobSucceeded only
Stderr - Passed on JobStderr and JobFailed
ReturnValue - Passed on JobFailed

This handler uses other configuration options to control it's behaviour as follows :-

EventsToReport

Comma separated list of events to report on or 'all' for al of them of 'none' for none of them Defaults to qq/JobFailed,JobSucceeded,JobStderr/

e.g.

use Schedule::Pluggable ( EventsToReport => qw/JobQueued,JobFailed,JobSucceeded,JobStderr/ );

PrefixWithTimeStamp

whether to prefix messages with the current time in dd/mm/yyyy HH::MM::SS format.

Defaults to 1 (timestamp is produced)

MessagesTo

where messages are sent - stdout by default

If supplied a filehandle, will call the print method on it and pass the details, for anything else will call directly. So this could be a Log::Log4perl method e.g. $log->info or $log->{ Category }->info

ErrorsTo

where error messages are sent - stderr by default

If supplied a filehandle, will call the print method on it and pass the details, for anything else will call directly. So this could be a Log::Log4perl method e.g. $log->error or $log->{ Category }->error

e.g.

use Schedule::Pluggable ( ErrorsTo => \&my_logger );

or

use Schedule::Pluggable; my $p = Schedule::Pluggable->new( MessagesTo => \&my_logger );

JOB CONIFIGURATION FORMAT

A Job entry can be a scalar value in which case it is assumed to contain a command to run or a hash containing some or all of the following :-

name

the name of the job

command - command to run
params - array of parameters to the command
groups - array of groups to which the job belongs
prerequisites - array of jobs or groups which must have completed successfully before job with start
dependencies - array of jobs or groups which must wait until this job has completed successfully before they will start

Obviously the bare minimum is to supply a command to run If a name is not supplied, it will be allocated one in the format Jobn where n is an incrementing number starting at 1 and increases with each job specified

METHODS

run_in_series ( $job_specification )

Utility method to run the supplied jobs in series by creating dependencies where each job is dependant on the previous one and then calls run_schedule with the revised definition

run_in_parallel ( $job_specification )

Runs the supplied jobs in parallel

Utility method to run the supplied jobs in parallel by removing and dependencies which are defined and the call run_schedule

run_schedule ( $job_specification )

The main method of the module - takes a supplied job definition - processes the information to validate and expand the definition and then runs the jobs as specified. When any event occurs, the appropriate callback is called if required to report on progress and on completion returns a structure detailing what happened in the following format :-

$status = { TotalJobs => <total number of jobs in schedule>, TotalFailed => <number of jobs which failed>, TotalFinished => <number of jobs which finished>, TotalSucceeded' => <number of successfull jobs>' LastUpdate => 'dd/mm/yyyy hh::mm::ss', Failed => { <Job which failed> => { status => <return value of job>, stderr => [ 'error line 1', .... ], }, }, Jobs => { <Job Name> => { name => <Job Name>, command => <command> status => <return value of command> Pid => <Process Id>, timestarted => 'dd/mm/yyyy hh::mm::ss', timefinished=> 'dd/mm/yyyy hh::mm::ss', stderr => [ 'error line 1', .... ], stdout => [ 'output line 1', .... ], }, ........ }, };

BUILDARGS Handles module options via import or passed on objet creation
BUILD Handles loading plugins

JOB DEFINITIONS

Jobs are specified as reference to an array which can contain either a list of commands ot run or as hash values

scalar values containing commands to run
hashes containing at least one key 'command' with the value containing the command to run

AUTHOR -

Tony Edwardson <Tony@Edwardson.co.uk>

KNOWN ERRORS

None yet - let me know if you find any

TODO

Improve Test Suite
Improve Error Handling
Add more Plugins
Handle Job Timeouts