NAME
Sub::NoRepeat - Call a subroutine or run a command, but not repeatedly
VERSION
This document describes version 0.04 of Sub::NoRepeat (from Perl
distribution Sub-NoRepeat), released on 2017-07-10.
SYNOPSIS
use Sub::NoRepeat qw(norepeat);
# run coderef
norepeat(code => \&sub1);
# won't run the same coderef again, noop
norepeat(code => \&sub1);
# run coderef because this one is different
norepeat(code => sub { ... });
# won't repeat because we use sub1 as key
norepeat(code => sub { ... }, key => \&sub1);
# run external command instead of coderef, die on non-zero exit code
norepeat(command => ['somecmd', '--cmdopt', ...]);
# will repeat after 24 hours
norepeat(period => '24h', ...);
# will repeat after change of day (equals to once daily):
norepeat(period => 'daily', ...);
# allows twice daily
norepeat(period => 'daily', num=>2, ...);
DESCRIPTION
This module is a generalization of the concept of App::norepeat and
possibly will supersede it in the future.
DATA FILE
Data file is a line-oriented text file, using labeled tab-separated
value format (). Each row contains these labels:
"time" (a timestamp either in the format of UTC
ISO8601"YYYY-MM-DDTHH:MM:SSZ", local ISO8601 "YYYY-MM-DDTHH:MM:SS", or
Unix timestamp), "key" (tabs and newlines will be converted to spaces).
The rows are assumed to be sorted chronologically (increasing time).
FUNCTIONS
norepeat
Usage:
norepeat(%args) -> any
Call a subroutine or run a command, but not repeatedly.
This routine allows you to avoid repeat execution of the same
subroutine/command. You can customize the key (which command/code are
considered the same, the default is the whole command or ref address of
subroutine), the repeat period, and some other stuffs.
It works simply by recording the keys and timestamps in a data file
(defaults to "~/norepeat.dat", can be customized) after successful
execution of commands/subroutines. Commands might still repeat if
"norepeat" fails to record to data file (e.g. disk is full, permission
problem).
Keywords: repeat interval, not too frequently, not more often than, at
most, once daily, weekly, monthly, yearly, period, limit rate.
This function is not exported by default, but exportable.
Arguments ('*' denotes required arguments):
* code => *code*
* command => *array[str]*
* data_file => *str*
Set filename to record execution to. Defaults to "~/norepeat.dat".
* ignore_failure => *bool* (default: 0)
By default, if command exits with non-zero status (or subroutine
dies), it is assumed to be a failure and won't be recorded in the
data file. Another invocation will be allowed to repeat. This option
will disregard exit status or trap exception and will still log the
data file.
* key => *str*
Key to use when recording event in data file.
Set key for determining which commands/subroutines are considered
the same.
If you use "command", by default it will be the entire command.
If you use "code", by default it will be the ref address of the
code, e.g. "CODE(0x1655800)".
* now => *int*
Assume current timestamp is this value.
* num => *int* (default: 1)
Allow (num-1) repeating during the same period.
The default (1) allows no repetition during the same period. A value
of 2 means allow repeat once (for a total of 2 executions).
* period => *str* (default: "forever")
Set maximum period of repeat detection. The default (when not
specified) is forever, which means to never allow repeat, ever, if
the same key (command or subroutine) has been run.
Can either be set to " (sec|min|hour|day|week|month|year)"
to express elapsed period after the last run, or
"(hourly|daily|weekly|monthly|yearly)" to express no repetition
before the named period (hour|day|week|month|year) changes.
For example, if period is "2 hour" then subsequent invocation won't
repeat commands until 2 hours have elapsed. In other words,
command/code won't repeat until the next 2 hours. Note that a month
is defined as 30.5 days and a year is defined as 365.25 days.
If period is "monthly", command/code won't repeat execution until
the month changes (e.g. from June to July). If you execute the first
command on June 3rd, command won't repeat until July 1st. The same
thing would happen if you first executed the command/code on June
30th.
When comparing, local times will be used.
Return value: (any)
HOMEPAGE
Please visit the project's homepage at
.
SOURCE
Source repository is at
.
BUGS
Please report any bugs or feature requests on the bugtracker website
When submitting a bug or request, please include a test-file or a patch
to an existing test-file that illustrates the bug or desired feature.
SEE ALSO
App::norepeat, the CLI version.
Unix cron facility for periodic/scheduling of execution.
Related: modules to limit the number of program instances that can run
at a single time: Proc::Govern, Sys::RunAlone.
AUTHOR
perlancar
COPYRIGHT AND LICENSE
This software is copyright (c) 2017, 2015 by perlancar@cpan.org.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.