1Schedule::Cron::Events(U3s)er Contributed Perl DocumentatSicohnedule::Cron::Events(3)
2
6 Schedule::Cron::Events - Schedule::Cron::Events - take a line from a
7 crontab and find out when events will occur
8
10 version 1.96
11
13 use Schedule::Cron::Events;
14 my @mon = qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec);
15 # a crontab line which triggers an event every 5 minutes
17 # initialize the counter with the current time
18 my $cron1 = new Schedule::Cron::Events( '*/5 * * * * /bin/foo', Seconds => time() );
19 # or initialize it with a date, for example 09:51:13 on 21st June, 2002
21 my $cron2 = new Schedule::Cron::Events( '*/5 * * * * /bin/foo', Date => [ 13, 51, 9, 21, 5, 102 ] );
22 # you could say this too, to use the current time:
24 my $cron = new Schedule::Cron::Events( '*/5 * * * * /bin/foo', Date => [ ( localtime(time()) )[0..5] ] );
25 # find the next execution time
27 my ($sec, $min, $hour, $day, $month, $year) = $cron->nextEvent;
28 printf("Event will start next at %2d:%02d:%02d on %d %s, %d\n", $hour, $min, $sec, $day, $mon[$month], ($year+1900));
29 # find the following occurrence of the job
31 ($sec, $min, $hour, $day, $month, $year) = $cron->nextEvent;
32 printf("Following event will start at %2d:%02d:%02d on %d %s, %d\n", $hour, $min, $sec, $day, $mon[$month], ($year+1900));
33 # reset the counter back to the original date given to new()
35 $cron->resetCounter;
36 # find out when the job would have last run
38 ($sec, $min, $hour, $day, $month, $year) = $cron->previousEvent;
39 printf("Last event started at %2d:%02d:%02d on %d %s, %d\n", $hour, $min, $sec, $day, $mon[$month], ($year+1900));
40 # see when the job would have next run at a point in time
42 $cron->setCounterToDate(0, 18, 1, 26, 9, 85); # that's 26th October, 1985
43 ($sec, $min, $hour, $day, $month, $year) = $cron->nextEvent;
44 printf("Event did start at %2d:%02d:%02d on %d %s, %d\n", $hour, $min, $sec, $day, $mon[$month], ($year+1900));
45 # turn a local date into a Unix time
47 use Time::Local;
48 my $epochSecs = timelocal($sec, $min, $hour, $day, $month, $year);
49 print "...or that can be expressed as " . $epochSecs . " seconds which is " . localtime($epochSecs) . "\n";
50 Here is a sample of the output produced by that code:
52 # Event will start next at 0:45:00 on 28 Aug, 2002
54 # Following event will start at 0:50:00 on 28 Aug, 2002
55 # Last event started at 0:40:00 on 28 Aug, 2002
56 # Event did start at 1:20:00 on 26 Oct, 1985
57 # ...or that can be expressed as 499134000 seconds which is Sat Oct 26 01:20:00 1985
58 Note that results will vary according to your local time and timezone.
60
62 Given a line from a crontab, tells you the time at which cron will next
63 run the line, or when the last event occurred, relative to any date you
64 choose. The object keeps that reference date internally, and updates it
65 when you call nextEvent() or previousEvent() - such that successive
66 calls will give you a sequence of events going forward, or backwards,
67 in time.
68 Use setCounterToNow() to reset this reference time to the current date
70 on your system, or use setCounterToDate() to set the reference to any
71 arbitrary time, or resetCounter() to take the object back to the date
72 you constructed it with.
73 This module uses Set::Crontab to understand the date specification, so
75 we should be able to handle all forms of cron entries.
76
78 Schedule::Cron::Events - take a line from a crontab and find out when
79 events will occur
80
82 In the following, DATE_LIST is a list of 6 values suitable for passing
83 to Time::Local::timelocal() which are the same as the first 6 values
84 returned by the builtin localtime(), namely these 6 numbers in this
85 order
86 · seconds
88 a number 0 .. 59
90 · minutes
92 a number 0 .. 59
94 · hours
96 a number 0 .. 23
98 · dayOfMonth
100 a number 0 .. 31
102 · month
104 a number 0 .. 11 - January is *0*, December is *11*
106 · year
108 the desired year number *minus 1900*
110 new( CRONTAB_ENTRY, Seconds => REFERENCE_TIME, Date => [ DATE_LIST ] )
112 Returns a new object for the specified line from the crontab. The
113 first 5 fields of the line are actually parsed by Set::Crontab,
114 which should be able to handle the original crontab(5) ranges as
115 well as Vixie cron ranges and the like. It's up to you to supply a
116 valid line - if you supply a comment line, an environment variable
117 setting line, or a line which does not seem to begin with 5 fields
118 (e.g. a blank line), this method returns undef.
119 Give either the Seconds option or the Date option, not both.
121 Supply a six-element array (as described above) to specify the date
122 at which you want to start. Alternatively, the reference time is
123 the number of seconds since the epoch for the time you want to
124 start looking from.
125 If neither of the 'Seconds' and 'Date' options are given we use the
127 current time().
128 resetCounter()
130 Resets the object to the state when created (specifically resetting
131 the internal counter to the initial date provided)
132 nextEvent()
134 Returns a DATE_LIST for the next event following the current
135 reference time. Updates the reference time to the time of the
136 event.
137 previousEvent()
139 Returns a DATE_LIST for the last event preceding the current
140 reference time. Updates the reference time to the time of the
141 event.
142 setCounterToNow()
144 Sets the reference time to the current time.
145 setCounterToDate( DATE_LIST )
147 Sets the reference time to the time given, specified in seconds
148 since the epoch.
149 commandLine()
151 Returns the string that is the command to be executed as specified
152 in the crontab - i.e. without the leading date specification.
153
155 If something goes wrong the general approach is to raise a fatal error
156 with confess() so use eval {} to trap these errors. If you supply a
157 comment line to the constructor then you'll simply get back undef, not
158 a fatal error. If you supply a line like 'foo bar */15 baz qux
159 /bin/false' you'll get a confess().
160
162 Set::Crontab, Time::Local, Carp. Date::Manip is no longer required
163 thanks to B Paulsen.
164
166 Since January 2012 maintained by Petya Kohts (petya.kohts at gmail.com)
167
169 Copyright 2002 P Kent
170 This library is free software; you can redistribute it and/or modify it
172 under the same terms as Perl itself.
173
175 Petya Kent <pause@selsyn.co.uk>
176
178 This software is copyright (c) 2002 by Petya Kent.
179 This is free software; you can redistribute it and/or modify it under
181 the same terms as the Perl 5 programming language system itself.
182perl v5.32.0 2020-07-28 Schedule::Cron::Events(3)