Commit | Line | Data |
74e31b02 |
1 | package Catalyst::Plugin::Scheduler; |
2 | |
3 | use strict; |
4 | use warnings; |
f9d8e3cf |
5 | use base qw/Class::Accessor::Fast Class::Data::Inheritable/; |
cbf1ecfe |
6 | use DateTime; |
7 | use DateTime::Event::Cron; |
8 | use DateTime::TimeZone; |
68f800bd |
9 | use File::stat; |
74e31b02 |
10 | use NEXT; |
d2c7c91a |
11 | use Set::Scalar; |
f9d8e3cf |
12 | use Storable qw/lock_store lock_retrieve/; |
13 | use YAML; |
74e31b02 |
14 | |
8c698cac |
15 | our $VERSION = '0.03'; |
74e31b02 |
16 | |
cbf1ecfe |
17 | __PACKAGE__->mk_classdata( '_events' => [] ); |
68f800bd |
18 | __PACKAGE__->mk_accessors('_event_state'); |
cbf1ecfe |
19 | |
20 | sub schedule { |
21 | my ( $class, %args ) = @_; |
68f800bd |
22 | |
f9d8e3cf |
23 | unless ( $args{event} ) { |
68f800bd |
24 | Catalyst::Exception->throw( |
25 | message => 'The schedule method requires an event parameter' ); |
f9d8e3cf |
26 | } |
68f800bd |
27 | |
f9d8e3cf |
28 | my $conf = $class->config->{scheduler}; |
68f800bd |
29 | |
cbf1ecfe |
30 | my $event = { |
cbf1ecfe |
31 | trigger => $args{trigger}, |
f9d8e3cf |
32 | event => $args{event}, |
cbf1ecfe |
33 | auto_run => ( defined $args{auto_run} ) ? $args{auto_run} : 1, |
34 | }; |
68f800bd |
35 | |
cbf1ecfe |
36 | if ( $args{at} ) { |
68f800bd |
37 | |
cbf1ecfe |
38 | # replace keywords that Set::Crontab doesn't support |
39 | $args{at} = _prepare_cron( $args{at} ); |
68f800bd |
40 | |
cbf1ecfe |
41 | # parse the cron entry into a DateTime::Set |
42 | my $set; |
43 | eval { $set = DateTime::Event::Cron->from_cron( $args{at} ) }; |
68f800bd |
44 | if ($@) { |
45 | Catalyst::Exception->throw( |
46 | "Scheduler: Unable to parse 'at' value " |
47 | . $args{at} . ': ' |
48 | . $@ ); |
cbf1ecfe |
49 | } |
50 | else { |
51 | $event->{set} = $set; |
52 | } |
53 | } |
68f800bd |
54 | |
cbf1ecfe |
55 | push @{ $class->_events }, $event; |
56 | } |
57 | |
58 | sub dispatch { |
59 | my $c = shift; |
68f800bd |
60 | |
cbf1ecfe |
61 | $c->NEXT::dispatch(@_); |
68f800bd |
62 | |
f9d8e3cf |
63 | $c->_get_event_state(); |
68f800bd |
64 | |
65 | $c->_check_yaml(); |
66 | |
cbf1ecfe |
67 | # check if a minute has passed since our last check |
f9d8e3cf |
68 | # This check is not run if the user is manually triggering an event |
69 | if ( time - $c->_event_state->{last_check} < 60 ) { |
70 | return unless $c->req->params->{schedule_trigger}; |
cbf1ecfe |
71 | } |
f9d8e3cf |
72 | my $last_check = $c->_event_state->{last_check}; |
73 | $c->_event_state->{last_check} = time; |
74 | $c->_save_event_state(); |
68f800bd |
75 | |
76 | my $conf = $c->config->{scheduler}; |
f9d8e3cf |
77 | my $last_check_dt = DateTime->from_epoch( |
78 | epoch => $last_check, |
cbf1ecfe |
79 | time_zone => $conf->{time_zone} |
80 | ); |
81 | my $now = DateTime->now( time_zone => $conf->{time_zone} ); |
68f800bd |
82 | |
48390e8e |
83 | EVENT: |
cbf1ecfe |
84 | for my $event ( @{ $c->_events } ) { |
f9d8e3cf |
85 | my $next_run; |
68f800bd |
86 | |
87 | if ( $event->{trigger} |
88 | && $event->{trigger} eq $c->req->params->{schedule_trigger} ) |
89 | { |
90 | |
f9d8e3cf |
91 | # manual trigger, run it now |
92 | next EVENT unless $c->_event_authorized; |
93 | $next_run = $now; |
94 | } |
95 | else { |
96 | next EVENT unless $event->{set}; |
68f800bd |
97 | $next_run = $event->{set}->next($last_check_dt); |
f9d8e3cf |
98 | } |
68f800bd |
99 | |
cbf1ecfe |
100 | if ( $next_run <= $now ) { |
68f800bd |
101 | |
cbf1ecfe |
102 | # do some security checking for non-auto-run events |
103 | if ( !$event->{auto_run} ) { |
104 | next EVENT unless $c->_event_authorized; |
105 | } |
68f800bd |
106 | |
f9d8e3cf |
107 | # make sure we're the only process running this event |
68f800bd |
108 | next EVENT unless $c->_mark_running($event); |
109 | |
cbf1ecfe |
110 | my $event_name = $event->{trigger} || $event->{event}; |
68f800bd |
111 | $c->log->debug("Scheduler: Executing $event_name") |
f9d8e3cf |
112 | if $c->config->{scheduler}->{logging}; |
68f800bd |
113 | |
cbf1ecfe |
114 | # trap errors |
115 | local $c->{error} = []; |
68f800bd |
116 | |
cbf1ecfe |
117 | # run event |
118 | eval { |
68f800bd |
119 | |
cbf1ecfe |
120 | # do not allow the event to modify the response |
121 | local $c->res->{body}; |
122 | local $c->res->{cookies}; |
123 | local $c->res->{headers}; |
124 | local $c->res->{location}; |
125 | local $c->res->{status}; |
68f800bd |
126 | |
cbf1ecfe |
127 | if ( ref $event->{event} eq 'CODE' ) { |
68f800bd |
128 | $event->{event}->($c); |
cbf1ecfe |
129 | } |
130 | else { |
131 | $c->forward( $event->{event} ); |
132 | } |
133 | }; |
134 | my @errors = @{ $c->{error} }; |
135 | push @errors, $@ if $@; |
68f800bd |
136 | if (@errors) { |
137 | $c->log->error( |
138 | 'Scheduler: Error executing ' . "$event_name: $_" ) |
139 | for @errors; |
cbf1ecfe |
140 | } |
68f800bd |
141 | |
142 | $c->_mark_finished($event); |
cbf1ecfe |
143 | } |
144 | } |
145 | } |
146 | |
147 | sub setup { |
148 | my $c = shift; |
68f800bd |
149 | |
cbf1ecfe |
150 | # initial configuration |
48390e8e |
151 | $c->config->{scheduler}->{logging} ||= ( $c->debug ) ? 1 : 0; |
68f800bd |
152 | $c->config->{scheduler}->{time_zone} ||= $c->_detect_timezone(); |
cbf1ecfe |
153 | $c->config->{scheduler}->{state_file} ||= $c->path_to('scheduler.state'); |
154 | $c->config->{scheduler}->{hosts_allow} ||= '127.0.0.1'; |
8c698cac |
155 | $c->config->{scheduler}->{yaml_file} ||= $c->path_to('scheduler.yml'); |
68f800bd |
156 | |
f9d8e3cf |
157 | $c->NEXT::setup(@_); |
cbf1ecfe |
158 | } |
159 | |
68f800bd |
160 | # check and reload the YAML file with schedule data |
161 | sub _check_yaml { |
162 | my ($c) = @_; |
163 | |
164 | # each process needs to load the YAML file independently |
165 | if ( $c->_event_state->{yaml_mtime}->{$$} ||= 0 ) { |
166 | return if ( time - $c->_event_state->{last_check} < 60 ); |
167 | } |
168 | |
8c698cac |
169 | return unless -e $c->config->{scheduler}->{yaml_file}; |
68f800bd |
170 | |
171 | eval { |
8c698cac |
172 | my $mtime = ( stat $c->config->{scheduler}->{yaml_file} )->mtime; |
68f800bd |
173 | if ( $mtime > $c->_event_state->{yaml_mtime}->{$$} ) { |
174 | $c->_event_state->{yaml_mtime}->{$$} = $mtime; |
175 | $c->_save_event_state(); |
176 | |
177 | # wipe out all current events and reload from YAML |
178 | $c->_events( [] ); |
179 | |
8c698cac |
180 | my $yaml = YAML::LoadFile( $c->config->{scheduler}->{yaml_file} ); |
68f800bd |
181 | |
182 | foreach my $event ( @{$yaml} ) { |
183 | $c->schedule( %{$event} ); |
184 | } |
185 | |
186 | $c->log->info( "Scheduler: PID $$ loaded " |
187 | . scalar @{$yaml} |
188 | . ' events from YAML file' ) |
189 | if $c->config->{scheduler}->{logging}; |
190 | } |
191 | }; |
192 | if ($@) { |
193 | $c->log->error("Error reading YAML file: $@"); |
194 | } |
195 | } |
196 | |
cbf1ecfe |
197 | # Detect the current time zone |
198 | sub _detect_timezone { |
199 | my $c = shift; |
68f800bd |
200 | |
cbf1ecfe |
201 | my $tz; |
202 | eval { $tz = DateTime::TimeZone->new( name => 'local' ) }; |
203 | if ($@) { |
68f800bd |
204 | $c->log->warn( |
07305803 |
205 | 'Scheduler: Unable to autodetect local time zone, using UTC') |
206 | if $c->config->{scheduler}->{logging}; |
cbf1ecfe |
207 | return 'UTC'; |
208 | } |
209 | else { |
f9d8e3cf |
210 | $c->log->debug( |
68f800bd |
211 | 'Scheduler: Using autodetected time zone: ' . $tz->name ) |
212 | if $c->config->{scheduler}->{logging}; |
cbf1ecfe |
213 | return $tz->name; |
214 | } |
215 | } |
216 | |
217 | # Check for authorized users on non-auto events |
cbf1ecfe |
218 | sub _event_authorized { |
219 | my $c = shift; |
68f800bd |
220 | |
f9d8e3cf |
221 | # this should never happen, but just in case... |
68f800bd |
222 | return unless $c->req->address; |
223 | |
f9d8e3cf |
224 | my $hosts_allow = $c->config->{scheduler}->{hosts_allow}; |
68f800bd |
225 | $hosts_allow = [$hosts_allow] unless ref($hosts_allow) eq 'ARRAY'; |
d2c7c91a |
226 | my $allowed = Set::Scalar->new( @{$hosts_allow} ); |
227 | return $allowed->contains( $c->req->address ); |
f9d8e3cf |
228 | } |
229 | |
230 | # get the state from the state file |
231 | sub _get_event_state { |
232 | my $c = shift; |
68f800bd |
233 | |
f9d8e3cf |
234 | if ( -e $c->config->{scheduler}->{state_file} ) { |
68f800bd |
235 | $c->_event_state( |
236 | lock_retrieve $c->config->{scheduler}->{state_file} ); |
f9d8e3cf |
237 | } |
238 | else { |
68f800bd |
239 | |
f9d8e3cf |
240 | # initialize the state file |
68f800bd |
241 | $c->_event_state( |
242 | { last_check => time, |
243 | yaml_mtime => {}, |
244 | } |
245 | ); |
f9d8e3cf |
246 | $c->_save_event_state(); |
247 | } |
248 | } |
249 | |
250 | # Check the state file to ensure we are the only process running an event |
251 | sub _mark_running { |
252 | my ( $c, $event ) = @_; |
68f800bd |
253 | |
f9d8e3cf |
254 | $c->_get_event_state(); |
68f800bd |
255 | |
f9d8e3cf |
256 | return if $c->_event_state->{ $event->{event} }; |
68f800bd |
257 | |
f9d8e3cf |
258 | # this is a 2-step process to prevent race conditions |
259 | # 1. write the state file with our PID |
260 | $c->_event_state->{ $event->{event} } = $$; |
261 | $c->_save_event_state(); |
68f800bd |
262 | |
f9d8e3cf |
263 | # 2. re-read the state file and make sure it's got the same PID |
264 | $c->_get_event_state(); |
265 | if ( $c->_event_state->{ $event->{event} } == $$ ) { |
266 | return 1; |
267 | } |
68f800bd |
268 | |
f9d8e3cf |
269 | return; |
270 | } |
271 | |
272 | # Mark an event as finished |
273 | sub _mark_finished { |
274 | my ( $c, $event ) = @_; |
68f800bd |
275 | |
f9d8e3cf |
276 | $c->_event_state->{ $event->{event} } = 0; |
277 | $c->_save_event_state(); |
cbf1ecfe |
278 | } |
279 | |
f9d8e3cf |
280 | # update the state file on disk |
281 | sub _save_event_state { |
282 | my $c = shift; |
68f800bd |
283 | |
f9d8e3cf |
284 | lock_store $c->_event_state, $c->config->{scheduler}->{state_file}; |
cbf1ecfe |
285 | } |
286 | |
287 | # Set::Crontab does not support day names, or '@' shortcuts |
288 | sub _prepare_cron { |
289 | my $cron = shift; |
68f800bd |
290 | |
cbf1ecfe |
291 | return $cron unless $cron =~ /\w/; |
68f800bd |
292 | |
cbf1ecfe |
293 | my %replace = ( |
294 | jan => 1, |
295 | feb => 2, |
296 | mar => 3, |
297 | apr => 4, |
298 | may => 5, |
299 | jun => 6, |
300 | jul => 7, |
301 | aug => 8, |
302 | sep => 9, |
303 | 'oct' => 10, |
304 | nov => 11, |
305 | dec => 12, |
68f800bd |
306 | |
cbf1ecfe |
307 | sun => 0, |
308 | mon => 1, |
309 | tue => 2, |
310 | wed => 3, |
311 | thu => 4, |
312 | fri => 5, |
313 | sat => 6, |
68f800bd |
314 | |
cbf1ecfe |
315 | 'yearly' => '0 0 1 1 *', |
316 | 'annually' => '0 0 1 1 *', |
317 | 'monthly' => '0 0 1 * *', |
318 | 'weekly' => '0 0 * * 0', |
319 | 'daily' => '0 0 * * *', |
320 | 'midnight' => '0 0 * * *', |
321 | 'hourly' => '0 * * * *', |
322 | ); |
68f800bd |
323 | |
cbf1ecfe |
324 | for my $name ( keys %replace ) { |
325 | my $value = $replace{$name}; |
68f800bd |
326 | |
cbf1ecfe |
327 | if ( $cron =~ /^\@$name/ ) { |
328 | $cron = $value; |
329 | last; |
330 | } |
331 | else { |
332 | $cron =~ s/$name/$value/i; |
333 | last unless $cron =~ /\w/; |
334 | } |
335 | } |
336 | |
337 | return $cron; |
338 | } |
339 | |
74e31b02 |
340 | 1; |
341 | __END__ |
342 | |
343 | =pod |
344 | |
345 | =head1 NAME |
346 | |
347 | Catalyst::Plugin::Scheduler - Schedule events to run in a cron-like fashion |
348 | |
349 | =head1 SYNOPSIS |
350 | |
351 | use Catalyst qw/Scheduler/; |
352 | |
353 | # run remove_sessions in the Cron controller every hour |
354 | __PACKAGE__->schedule( |
355 | at => '0 * * * *', |
356 | event => '/cron/remove_sessions' |
357 | ); |
358 | |
359 | # Run a subroutine at 4:05am every Sunday |
360 | __PACKAGE__->schedule( |
361 | at => '5 4 * * sun', |
362 | event => \&do_stuff, |
363 | ); |
364 | |
68f800bd |
365 | # A long-running scheduled event that must be triggered |
366 | # manually by an authorized user |
367 | __PACKAGE__->schedule( |
368 | trigger => 'rebuild_search_index', |
369 | event => '/cron/rebuild_search_index', |
370 | ); |
371 | $ wget -q http://www.myapp.com/?schedule_trigger=rebuild_search_index |
f9d8e3cf |
372 | |
74e31b02 |
373 | =head1 DESCRIPTION |
374 | |
375 | This plugin allows you to schedule events to run at recurring intervals. |
376 | Events will run during the first request which meets or exceeds the specified |
377 | time. Depending on the level of traffic to the application, events may or may |
378 | not run at exactly the correct time, but it should be enough to satisfy many |
379 | basic scheduling needs. |
380 | |
381 | =head1 CONFIGURATION |
382 | |
383 | Configuration is optional and is specified in MyApp->config->{scheduler}. |
384 | |
385 | =head2 logging |
386 | |
387 | Set to 1 to enable logging of events as they are executed. This option is |
388 | enabled by default when running under -Debug mode. Errors are always logged |
389 | regardless of the value of this option. |
390 | |
cbf1ecfe |
391 | =head2 time_zone |
392 | |
393 | The time zone of your system. This will be autodetected where possible, or |
394 | will default to UTC (GMT). You can override the detection by providing a |
395 | valid L<DateTime> time zone string, such as 'America/New_York'. |
396 | |
74e31b02 |
397 | =head2 state_file |
398 | |
399 | The current state of every event is stored in a file. By default this is |
f9d8e3cf |
400 | $APP_HOME/scheduler.state. This file is created on the first request if it |
401 | does not already exist. |
74e31b02 |
402 | |
68f800bd |
403 | =head2 yaml_file |
404 | |
405 | The location of the optional YAML event configuration file. By default this |
406 | is $APP_HOME/scheduler.yml. |
407 | |
74e31b02 |
408 | =head2 hosts_allow |
409 | |
410 | This option specifies IP addresses for trusted users. This option defaults |
411 | to 127.0.0.1. Multiple addresses can be specified by using an array |
412 | reference. This option is used for both events where auto_run is set to 0 |
413 | and for manually-triggered events. |
414 | |
415 | __PACKAGE__->config->{scheduler}->{hosts_allow} = '192.168.1.1'; |
416 | __PACKAGE__->config->{scheduler}->{hosts_allow} = [ |
417 | '127.0.0.1', |
418 | '192.168.1.1' |
419 | ]; |
420 | |
421 | =head1 SCHEDULING |
422 | |
423 | =head2 AUTOMATED EVENTS |
424 | |
425 | Events are scheduled by calling the class method C<schedule>. |
426 | |
427 | MyApp->schedule( |
428 | at => '0 * * * *', |
429 | event => '/cron/remove_sessions', |
430 | ); |
431 | |
432 | package MyApp::Controller::Cron; |
433 | |
434 | sub remove_sessions : Private { |
435 | my ( $self, $c ) = @_; |
436 | |
437 | $c->delete_expired_sessions; |
438 | } |
439 | |
440 | =head3 at |
441 | |
442 | The time to run an event is specified using L<crontab(5)>-style syntax. |
443 | |
444 | 5 0 * * * # 5 minutes after midnight, every day |
445 | 15 14 1 * * # run at 2:15pm on the first of every month |
446 | 0 22 * * 1-5 # run at 10 pm on weekdays |
447 | 5 4 * * sun # run at 4:05am every Sunday |
448 | |
449 | From crontab(5): |
450 | |
451 | field allowed values |
452 | ----- -------------- |
453 | minute 0-59 |
454 | hour 0-23 |
455 | day of month 1-31 |
456 | month 0-12 (or names, see below) |
457 | day of week 0-7 (0 or 7 is Sun, or use names) |
458 | |
459 | Instead of the first five fields, one of seven special strings may appear: |
460 | |
461 | string meaning |
462 | ------ ------- |
463 | @yearly Run once a year, "0 0 1 1 *". |
464 | @annually (same as @yearly) |
465 | @monthly Run once a month, "0 0 1 * *". |
466 | @weekly Run once a week, "0 0 * * 0". |
467 | @daily Run once a day, "0 0 * * *". |
468 | @midnight (same as @daily) |
469 | @hourly Run once an hour, "0 * * * *". |
470 | |
471 | =head3 event |
472 | |
473 | The event to run at the specified time can be either a Catalyst private |
474 | action path or a coderef. Both types of event methods will receive the $c |
475 | object from the current request, but you must not rely on any request-specific |
476 | information present in $c as it will be from a random user request at or near |
477 | the event's specified run time. |
478 | |
479 | Important: Methods used for events should be marked C<Private> so that |
480 | they can not be executed via the browser. |
481 | |
482 | =head3 auto_run |
483 | |
484 | The auto_run parameter specifies when the event is allowed to be executed. |
485 | By default this option is set to 1, so the event will be executed during the |
486 | first request that matches the specified time in C<at>. |
487 | |
488 | If set to 0, the event will only run when a request is made by a user from |
489 | an authorized address. The purpose of this option is to allow long-running |
490 | tasks to execute only for certain users. |
491 | |
492 | MyApp->schedule( |
493 | at => '0 0 * * *', |
494 | event => '/cron/rebuild_search_index', |
495 | auto_run => 0, |
496 | ); |
497 | |
498 | package MyApp::Controller::Cron; |
499 | |
500 | sub rebuild_search_index : Private { |
501 | my ( $self, $c ) = @_; |
502 | |
503 | # rebuild the search index, this may take a long time |
504 | } |
505 | |
506 | Now, the search index will only be rebuilt when a request is made from a user |
507 | whose IP address matches the list in the C<hosts_allow> config option. To |
508 | run this event, you probably want to ping the app from a cron job. |
509 | |
f9d8e3cf |
510 | 0 0 * * * wget -q http://www.myapp.com/ |
74e31b02 |
511 | |
512 | =head2 MANUAL EVENTS |
513 | |
514 | To create an event that does not run on a set schedule and must be manually |
515 | triggered, you can specify the C<trigger> option instead of C<at>. |
516 | |
517 | __PACKAGE__->schedule( |
518 | trigger => 'send_email', |
519 | event => '/events/send_email', |
520 | ); |
521 | |
522 | The event may then be triggered by a standard web request from an authorized |
523 | user. The trigger to run is specified by using a special GET parameter, |
524 | 'schedule_trigger'; the path requested does not matter. |
525 | |
526 | http://www.myapp.com/?schedule_trigger=send_email |
527 | |
528 | By default, manual events may only be triggered by requests made from |
529 | localhost (127.0.0.1). To allow other addresses to run events, use the |
68f800bd |
530 | configuration option L</hosts_allow>. |
531 | |
532 | =head1 SCHEDULING USING A YAML FILE |
533 | |
534 | As an alternative to using the schedule() method, you may define scheduled |
535 | events in an external YAML file. By default, the plugin looks for the |
536 | existence of a file called C<schedule.yml> in your application's home |
537 | directory. You can change the filename using the configuration option |
538 | L</yaml_file>. |
539 | |
540 | Modifications to this file will be re-read once per minute during the normal |
541 | event checking process. |
542 | |
543 | Here's an example YAML configuration file with 4 events. Each event is |
544 | denoted with a '-' character, followed by the same parameters used by the |
545 | C<schedule> method. Note that coderef events are not supported by the YAML |
546 | file. |
547 | |
548 | --- |
549 | - at: '* * * * *' |
550 | event: /cron/delete_sessions |
551 | - event: /cron/send_email |
552 | trigger: send_email |
553 | - at: '@hourly' |
554 | event: /cron/hourly |
555 | - at: 0 0 * * * |
556 | auto_run: 0 |
557 | event: /cron/rebuild_search_index |
74e31b02 |
558 | |
559 | =head1 SECURITY |
560 | |
561 | All events are run inside of an eval container. This protects the user from |
562 | receiving any error messages or page crashes if an event fails to run |
563 | properly. All event errors are logged, even if logging is disabled. |
564 | |
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565 | =head1 PLUGIN SUPPORT |
566 | |
567 | Other plugins may register scheduled events if they need to perform periodic |
568 | maintenance. Plugin authors, B<be sure to inform your users> if you do this! |
569 | Events should be registered from a plugin's C<setup> method. |
570 | |
571 | sub setup { |
572 | my $c = shift; |
573 | $c->NEXT::setup(@_); |
574 | |
575 | if ( $c->can('schedule') ) { |
576 | $c->schedule( |
577 | at => '0 * * * *', |
578 | event => \&cleanup, |
579 | ); |
580 | } |
581 | } |
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582 | |
583 | =head1 CAVEATS |
584 | |
585 | The time at which an event will run is determined completely by the requests |
586 | made to the application. Apps with heavy traffic may have events run at very |
587 | close to the correct time, whereas apps with low levels of traffic may see |
588 | events running much later than scheduled. If this is a problem, you can use |
589 | a real cron entry that simply hits your application at the desired time. |
590 | |
591 | 0 * * * * wget -q http://www.myapp.com/ |
592 | |
593 | Events which consume a lot of time will slow the request processing for the |
594 | user who triggers the event. For these types of events, you should use |
595 | auto_run => 0 or manual event triggering. |
596 | |
597 | =head1 PERFORMANCE |
598 | |
599 | The plugin only checks once per minute if any events need to be run, so the |
600 | overhead on each request is minimal. On my test server, the difference |
601 | between running with Scheduler and without was only around 0.02% (0.004 |
602 | seconds). |
603 | |
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604 | Of course, when a scheduled event runs, performance will depend on what's |
605 | being run in the event. |
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606 | |
607 | =head1 METHODS |
608 | |
609 | =head2 schedule |
610 | |
611 | Schedule is a class method for adding scheduled events. See the |
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612 | L<"/SCHEDULING"> section for more information. |
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613 | |
614 | =head1 INTERNAL METHODS |
615 | |
616 | The following methods are extended by this plugin. |
617 | |
618 | =over 4 |
619 | |
620 | =item dispatch |
621 | |
622 | The main scheduling logic takes place during the dispatch phase. |
623 | |
624 | =item setup |
625 | |
626 | =back |
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627 | |
628 | =head1 SEE ALSO |
629 | |
630 | L<crontab(5)> |
631 | |
632 | =head1 AUTHOR |
633 | |
634 | Andy Grundman, <andy@hybridized.org> |
635 | |
636 | =head1 COPYRIGHT |
637 | |
638 | This program is free software, you can redistribute it and/or modify it |
639 | under the same terms as Perl itself. |
640 | |
641 | =cut |