1 package Catalyst::Plugin::Scheduler;
5 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
7 use DateTime::Event::Cron;
8 use DateTime::TimeZone;
12 use Storable qw/lock_store lock_retrieve/;
15 our $VERSION = '0.07';
17 __PACKAGE__->mk_classdata( '_events' => [] );
18 __PACKAGE__->mk_accessors('_event_state');
21 my ( $class, %args ) = @_;
23 unless ( $args{event} ) {
24 Catalyst::Exception->throw(
25 message => 'The schedule method requires an event parameter' );
28 my $conf = $class->config->{scheduler};
31 trigger => $args{trigger},
32 event => $args{event},
33 auto_run => ( defined $args{auto_run} ) ? $args{auto_run} : 1,
38 # replace keywords that Set::Crontab doesn't support
39 $args{at} = _prepare_cron( $args{at} );
41 # parse the cron entry into a DateTime::Set
43 eval { $set = DateTime::Event::Cron->from_cron( $args{at} ) };
45 Catalyst::Exception->throw(
46 "Scheduler: Unable to parse 'at' value "
51 $event->{at} = $args{at};
56 push @{ $class->_events }, $event;
62 $c->NEXT::dispatch(@_);
64 $c->_get_event_state();
68 # check if a minute has passed since our last check
69 # This check is not run if the user is manually triggering an event
70 if ( time - $c->_event_state->{last_check} < 60 ) {
71 return unless $c->req->params->{schedule_trigger};
73 my $last_check = $c->_event_state->{last_check};
74 $c->_event_state->{last_check} = time;
75 $c->_save_event_state();
77 my $conf = $c->config->{scheduler};
78 my $last_check_dt = DateTime->from_epoch(
80 time_zone => $conf->{time_zone}
82 my $now = DateTime->now( time_zone => $conf->{time_zone} );
85 for my $event ( @{ $c->_events } ) {
88 if ( $event->{trigger} && $c->req->params->{schedule_trigger}
89 && $event->{trigger} eq $c->req->params->{schedule_trigger} )
92 # manual trigger, run it now
93 next EVENT unless $c->_event_authorized;
97 next EVENT unless $event->{set};
98 $next_run = $event->{set}->next($last_check_dt);
101 if ( $next_run <= $now ) {
103 # do some security checking for non-auto-run events
104 if ( !$event->{auto_run} ) {
105 next EVENT unless $c->_event_authorized;
108 # make sure we're the only process running this event
109 next EVENT unless $c->_mark_running($event);
111 my $event_name = $event->{trigger} || $event->{event};
112 $c->log->debug("Scheduler: Executing $event_name")
113 if $c->config->{scheduler}->{logging};
116 local $c->{error} = [];
118 # return value/output from the event, if any
124 # do not allow the event to modify the response
125 local $c->res->{body};
126 local $c->res->{cookies};
127 local $c->res->{headers};
128 local $c->res->{location};
129 local $c->res->{status};
131 if ( ref $event->{event} eq 'CODE' ) {
132 $output = $event->{event}->($c);
135 $output = $c->forward( $event->{event} );
138 my @errors = @{ $c->{error} };
139 push @errors, $@ if $@;
142 'Scheduler: Error executing ' . "$event_name: $_" )
144 $output = join '; ', @errors;
147 $c->_mark_finished( $event, $output );
155 # initial configuration
156 $c->config->{scheduler}->{logging} ||= ( $c->debug ) ? 1 : 0;
157 $c->config->{scheduler}->{time_zone} ||= $c->_detect_timezone();
158 $c->config->{scheduler}->{state_file} ||= $c->path_to('scheduler.state');
159 $c->config->{scheduler}->{hosts_allow} ||= '127.0.0.1';
160 $c->config->{scheduler}->{yaml_file} ||= $c->path_to('scheduler.yml');
168 return ( $c->NEXT::dump_these(@_) ) unless @{ $c->_events };
170 # for debugging, we dump out a list of all events with their next
173 $c->NEXT::dump_these(@_),
174 [ 'Scheduled Events', $c->scheduler_state ],
178 sub scheduler_state {
181 $c->_get_event_state();
183 my $conf = $c->config->{scheduler};
184 my $now = DateTime->now( time_zone => $conf->{time_zone} );
186 my $last_check = $c->_event_state->{last_check};
187 my $last_check_dt = DateTime->from_epoch(
188 epoch => $last_check,
189 time_zone => $conf->{time_zone},
193 for my $event ( @{ $c->_events } ) {
195 for my $key ( qw/at trigger event auto_run/ ) {
196 $dump->{$key} = $event->{$key} if $event->{$key};
199 # display the next run time
200 if ( $event->{set} ) {
201 my $next_run = $event->{set}->next($last_check_dt);
204 . q{ } . $next_run->hms
205 . q{ } . $next_run->time_zone_short_name;
208 # display the last run time
210 = $c->_event_state->{events}->{ $event->{event} }->{last_run};
212 $last_run = DateTime->from_epoch(
214 time_zone => $conf->{time_zone},
218 . q{ } . $last_run->hms
219 . q{ } . $last_run->time_zone_short_name;
222 # display the result of the last run
224 = $c->_event_state->{events}->{ $event->{event} }->{last_output};
226 $dump->{last_output} = $output;
229 push @{$event_dump}, $dump;
235 # check and reload the YAML file with schedule data
239 # each process needs to load the YAML file independently
240 if ( $c->_event_state->{yaml_mtime}->{$$} ||= 0 ) {
241 return if ( time - $c->_event_state->{last_check} < 60 );
244 return unless -e $c->config->{scheduler}->{yaml_file};
247 my $mtime = ( stat $c->config->{scheduler}->{yaml_file} )->mtime;
248 if ( $mtime > $c->_event_state->{yaml_mtime}->{$$} ) {
249 $c->_event_state->{yaml_mtime}->{$$} = $mtime;
251 # clean up old PIDs listed in yaml_mtime
252 foreach my $pid ( keys %{ $c->_event_state->{yaml_mtime} } ) {
253 if ( $c->_event_state->{yaml_mtime}->{$pid} < $mtime ) {
254 delete $c->_event_state->{yaml_mtime}->{$pid};
257 $c->_save_event_state();
259 # wipe out all current events and reload from YAML
262 my $file = $c->config->{scheduler}->{yaml_file};
263 my $yaml = YAML::LoadFile( "$file" );
265 foreach my $event ( @{$yaml} ) {
266 $c->schedule( %{$event} );
269 $c->log->info( "Scheduler: PID $$ loaded "
271 . ' events from YAML file' )
272 if $c->config->{scheduler}->{logging};
276 $c->log->error("Scheduler: Error reading YAML file: $@");
280 # Detect the current time zone
281 sub _detect_timezone {
285 eval { $tz = DateTime::TimeZone->new( name => 'local' ) };
288 'Scheduler: Unable to autodetect local time zone, using UTC')
289 if $c->config->{scheduler}->{logging};
294 'Scheduler: Using autodetected time zone: ' . $tz->name )
295 if $c->config->{scheduler}->{logging};
300 # Check for authorized users on non-auto events
301 sub _event_authorized {
304 # this should never happen, but just in case...
305 return unless $c->req->address;
307 my $hosts_allow = $c->config->{scheduler}->{hosts_allow};
308 $hosts_allow = [$hosts_allow] unless ref($hosts_allow) eq 'ARRAY';
309 my $allowed = Set::Scalar->new( @{$hosts_allow} );
310 return $allowed->contains( $c->req->address );
313 # get the state from the state file
314 sub _get_event_state {
317 if ( -e $c->config->{scheduler}->{state_file} ) {
319 lock_retrieve $c->config->{scheduler}->{state_file} );
323 # initialize the state file
325 { last_check => time,
330 $c->_save_event_state();
334 # Check the state file to ensure we are the only process running an event
336 my ( $c, $event ) = @_;
338 $c->_get_event_state();
341 $c->_event_state->{events}->{ $event->{event} }->{running};
343 # this is a 2-step process to prevent race conditions
344 # 1. write the state file with our PID
345 $c->_event_state->{events}->{ $event->{event} }->{running} = $$;
346 $c->_save_event_state();
348 # 2. re-read the state file and make sure it's got the same PID
349 $c->_get_event_state();
350 if ( $c->_event_state->{events}->{ $event->{event} }->{running} == $$ ) {
357 # Mark an event as finished
359 my ( $c, $event, $output ) = @_;
361 $c->_event_state->{events}->{ $event->{event} }->{running} = 0;
362 $c->_event_state->{events}->{ $event->{event} }->{last_run} = time;
363 $c->_event_state->{events}->{ $event->{event} }->{last_output} = $output;
364 $c->_save_event_state();
367 # update the state file on disk
368 sub _save_event_state {
371 lock_store $c->_event_state, $c->config->{scheduler}->{state_file};
374 # Set::Crontab does not support day names, or '@' shortcuts
378 return $cron unless $cron =~ /\w/;
404 'yearly' => '0 0 1 1 *',
405 'annually' => '0 0 1 1 *',
406 'monthly' => '0 0 1 * *',
407 'weekly' => '0 0 * * 0',
408 'daily' => '0 0 * * *',
409 'midnight' => '0 0 * * *',
410 'hourly' => '0 * * * *',
413 if ( $cron =~ /^\@/ ) {
415 return $replace_at{ $cron };
418 for my $name ( keys %replace ) {
419 my $value = $replace{$name};
420 $cron =~ s/$name/$value/i;
421 last unless $cron =~ /\w/;
433 Catalyst::Plugin::Scheduler - Schedule events to run in a cron-like fashion
437 use Catalyst qw/Scheduler/;
439 # run remove_sessions in the Cron controller every hour
440 __PACKAGE__->schedule(
442 event => '/cron/remove_sessions'
445 # Run a subroutine at 4:05am every Sunday
446 __PACKAGE__->schedule(
451 # A long-running scheduled event that must be triggered
452 # manually by an authorized user
453 __PACKAGE__->schedule(
454 trigger => 'rebuild_search_index',
455 event => '/cron/rebuild_search_index',
457 $ wget -q http://www.myapp.com/?schedule_trigger=rebuild_search_index
461 This plugin allows you to schedule events to run at recurring intervals.
462 Events will run during the first request which meets or exceeds the specified
463 time. Depending on the level of traffic to the application, events may or may
464 not run at exactly the correct time, but it should be enough to satisfy many
465 basic scheduling needs.
469 Configuration is optional and is specified in MyApp->config->{scheduler}.
473 Set to 1 to enable logging of events as they are executed. This option is
474 enabled by default when running under -Debug mode. Errors are always logged
475 regardless of the value of this option.
479 The time zone of your system. This will be autodetected where possible, or
480 will default to UTC (GMT). You can override the detection by providing a
481 valid L<DateTime> time zone string, such as 'America/New_York'.
485 The current state of every event is stored in a file. By default this is
486 $APP_HOME/scheduler.state. This file is created on the first request if it
487 does not already exist.
491 The location of the optional YAML event configuration file. By default this
492 is $APP_HOME/scheduler.yml.
496 This option specifies IP addresses for trusted users. This option defaults
497 to 127.0.0.1. Multiple addresses can be specified by using an array
498 reference. This option is used for both events where auto_run is set to 0
499 and for manually-triggered events.
501 __PACKAGE__->config->{scheduler}->{hosts_allow} = '192.168.1.1';
502 __PACKAGE__->config->{scheduler}->{hosts_allow} = [
509 =head2 AUTOMATED EVENTS
511 Events are scheduled by calling the class method C<schedule>.
515 event => '/cron/remove_sessions',
518 package MyApp::Controller::Cron;
520 sub remove_sessions : Private {
521 my ( $self, $c ) = @_;
523 $c->delete_expired_sessions;
528 The time to run an event is specified using L<crontab(5)>-style syntax.
530 5 0 * * * # 5 minutes after midnight, every day
531 15 14 1 * * # run at 2:15pm on the first of every month
532 0 22 * * 1-5 # run at 10 pm on weekdays
533 5 4 * * sun # run at 4:05am every Sunday
542 month 0-12 (or names, see below)
543 day of week 0-7 (0 or 7 is Sun, or use names)
545 Instead of the first five fields, one of seven special strings may appear:
549 @yearly Run once a year, "0 0 1 1 *".
550 @annually (same as @yearly)
551 @monthly Run once a month, "0 0 1 * *".
552 @weekly Run once a week, "0 0 * * 0".
553 @daily Run once a day, "0 0 * * *".
554 @midnight (same as @daily)
555 @hourly Run once an hour, "0 * * * *".
559 The event to run at the specified time can be either a Catalyst private
560 action path or a coderef. Both types of event methods will receive the $c
561 object from the current request, but you must not rely on any request-specific
562 information present in $c as it will be from a random user request at or near
563 the event's specified run time.
565 Important: Methods used for events should be marked C<Private> so that
566 they can not be executed via the browser.
570 The auto_run parameter specifies when the event is allowed to be executed.
571 By default this option is set to 1, so the event will be executed during the
572 first request that matches the specified time in C<at>.
574 If set to 0, the event will only run when a request is made by a user from
575 an authorized address. The purpose of this option is to allow long-running
576 tasks to execute only for certain users.
580 event => '/cron/rebuild_search_index',
584 package MyApp::Controller::Cron;
586 sub rebuild_search_index : Private {
587 my ( $self, $c ) = @_;
589 # rebuild the search index, this may take a long time
592 Now, the search index will only be rebuilt when a request is made from a user
593 whose IP address matches the list in the C<hosts_allow> config option. To
594 run this event, you probably want to ping the app from a cron job.
596 0 0 * * * wget -q http://www.myapp.com/
600 To create an event that does not run on a set schedule and must be manually
601 triggered, you can specify the C<trigger> option instead of C<at>.
603 __PACKAGE__->schedule(
604 trigger => 'send_email',
605 event => '/events/send_email',
608 The event may then be triggered by a standard web request from an authorized
609 user. The trigger to run is specified by using a special GET parameter,
610 'schedule_trigger'; the path requested does not matter.
612 http://www.myapp.com/?schedule_trigger=send_email
614 By default, manual events may only be triggered by requests made from
615 localhost (127.0.0.1). To allow other addresses to run events, use the
616 configuration option L</hosts_allow>.
618 =head1 SCHEDULING USING A YAML FILE
620 As an alternative to using the schedule() method, you may define scheduled
621 events in an external YAML file. By default, the plugin looks for the
622 existence of a file called C<schedule.yml> in your application's home
623 directory. You can change the filename using the configuration option
626 Modifications to this file will be re-read once per minute during the normal
627 event checking process.
629 Here's an example YAML configuration file with 4 events. Each event is
630 denoted with a '-' character, followed by the same parameters used by the
631 C<schedule> method. Note that coderef events are not supported by the YAML
636 event: /cron/delete_sessions
637 - event: /cron/send_email
643 event: /cron/rebuild_search_index
647 All events are run inside of an eval container. This protects the user from
648 receiving any error messages or page crashes if an event fails to run
649 properly. All event errors are logged, even if logging is disabled.
651 =head1 PLUGIN SUPPORT
653 Other plugins may register scheduled events if they need to perform periodic
654 maintenance. Plugin authors, B<be sure to inform your users> if you do this!
655 Events should be registered from a plugin's C<setup> method.
661 if ( $c->can('schedule') ) {
671 The time at which an event will run is determined completely by the requests
672 made to the application. Apps with heavy traffic may have events run at very
673 close to the correct time, whereas apps with low levels of traffic may see
674 events running much later than scheduled. If this is a problem, you can use
675 a real cron entry that simply hits your application at the desired time.
677 0 * * * * wget -q http://www.myapp.com/
679 Events which consume a lot of time will slow the request processing for the
680 user who triggers the event. For these types of events, you should use
681 auto_run => 0 or manual event triggering.
685 The plugin only checks once per minute if any events need to be run, so the
686 overhead on each request is minimal. On my test server, the difference
687 between running with Scheduler and without was only around 0.02% (0.004
690 Of course, when a scheduled event runs, performance will depend on what's
691 being run in the event.
697 Schedule is a class method for adding scheduled events. See the
698 L<"/SCHEDULING"> section for more information.
700 =head2 scheduler_state
702 The current state of all scheduled events is available in an easy-to-use
703 format by calling $c->scheduler_state. You can use this data to build an
704 admin view into the scheduling engine, for example. This same data is also
705 displayed on the Catalyst debug screen.
707 This method returns an array reference containing a hash reference for each
712 'last_run' => '2005-12-29 16:29:33 EST',
716 'next_run' => '2005-12-30 00:00:00 EST',
717 'event' => '/cron/session_cleanup'
722 'next_run' => '2005-12-30 00:00:00 EST',
723 'event' => '/cron/build_rss'
727 =head1 INTERNAL METHODS
729 The following methods are extended by this plugin.
735 The main scheduling logic takes place during the dispatch phase.
739 On the Catalyst debug screen, all scheduled events are displayed along with
740 the next time they will be executed.
752 Andy Grundman, <andy@hybridized.org>
756 This program is free software, you can redistribute it and/or modify it
757 under the same terms as Perl itself.