package C4::Scheduler; # Copyright 2007 Liblime Ltd # # This file is part of Koha. # # Koha is free software; you can redistribute it and/or modify it # under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 3 of the License, or # (at your option) any later version. # # Koha is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with Koha; if not, see . use Modern::Perl; use C4::Context; use Schedule::At; our (@ISA, @EXPORT_OK); BEGIN { require Exporter; @ISA = qw(Exporter); @EXPORT_OK = qw(get_jobs get_at_jobs get_at_job add_at_job remove_at_job); } =head1 NAME C4::Scheduler - Module for running jobs with the unix at command =head1 SYNOPSIS use C4::Scheduler; =head1 DESCRIPTION =cut =head1 METHODS =head2 get_jobs(); This will return all scheduled jobs =cut sub get_jobs { my $jobs = get_at_jobs(); # add call to get cron jobs here too return ($jobs); } =head2 get_at_jobs(); This will return all At scheduled jobs =cut sub get_at_jobs { my %jobs = Schedule::At::getJobs(); return (\%jobs); } =head2 get_at_job($id) This will return the At job with the given id =cut sub get_at_job { my ($id)=@_; my %jobs = Schedule::At::getJobs(JOBID => $id); } =head2 add_at_job ($time,$command) Given a timestamp and a command this will schedule the job to run at that time. Returns true if the job is added to the queue and false otherwise. =cut sub add_at_job { my ($time,$command) = @_; # FIXME - a description of the task to be run # may be a better tag, since the tag is displayed # in the job list that the administrator sees - e.g., # "run report foo, send to foo@bar.com" Schedule::At::add(TIME => $time, COMMAND => $command, TAG => $command); # FIXME - this method of checking whether the job was added # to the queue is less than perfect: # # 1. Since the command is the tag, it is possible that there is # already a job in the queue with the same tag. However, since # the tag is what displays in the job list, we can't just # give it a unique ID. # 2. Schedule::At::add() is supposed to return a non-zero # value if it fails to add a job - however, it does # not check all error conditions - in particular, it does # not check the return value of the "at" run; it basically # complains only if it can't find at. # 3. Similary, Schedule::At::add() does not do something more useful, # such as returning the job ID. To be fair, it is possible # that 'at' does not allow this in any portable way. # 4. Although unlikely, it is possible that a job could be added # and completed instantly, thus dropping off the queue. my $job_found = 0; eval { my %jobs = Schedule::At::getJobs(TAG => $command); $job_found = scalar(keys %jobs) > 0; }; if ($@) { return 0; } else { return $job_found; } } sub remove_at_job { my ($jobid)=@_; Schedule::At::remove(JOBID => $jobid); } 1; __END__ =head1 BUGS At some point C should be refactored: =over =item At and C does not work on Win32. =item At is not installed by default on all platforms. =item The At queue used by Koha is owned by the httpd user. If multiple Koha databases share an Apache instance on a server, everybody can see everybody's jobs. =item There is no support for scheduling a job to run more than once. =back =head1 AUTHOR Chris Cormack =cut