NAME

Retry::Backoff - Retry a piece of code, with backoff strategies

VERSION

This document describes version 0.006 of Retry::Backoff (from Perl distribution Retry-Backoff), released on 2024-02-24.

SYNOPSIS

 use Retry::Backoff 'retry';

 # by default, will use Algorithm::Backoff::Exponential with these parameters:
 # - initial_delay =   1 (1 second)
 # - max_delay     = 300 (5 minutes)
 # - max_attempts  =  10
 retry { ... };

 # select backoff strategy (see corresponding Algorithm::Backoff::* for list of
 # parameters)
 retry { ... } strategy=>'Constant', initial_delay=>1, max_attempts=>10;

 # other available 'retry' arguments
 retry { ... }
     on_success       => sub { my $h = shift; ... },
     on_failure       => sub { my $h = shift; ... },
     on_final_failure => sub { my $h = shift; ... },
     retry_if         => sub { my $h = shift; ... },
     non_blocking     => 0;

DESCRIPTION

This module provides "retry" to retry a piece of code if it dies. Several backoff (delay between retries) strategies are available from Algorithm::Backoff:: modules.

FUNCTIONS

retry

Usage:

 retry { attempt-code... } %args;

Run attempt-code, retry if it dies. Known arguments:

• strategy

  String. Default is Exponential (with initial_delay=1, max_delay=300, and max_attempts=10).

• on_success

  Coderef. Will be called if attempt-code is deemed as successful.

• on_failure

  Coderef. Will be called if attempt-code is deemed to have failed.

• on_final_failure

  Coderef. Will be called if attempt-code is deemed to have failed and will not be retried.

• retry_if

  Coderef. If this argument is not specified, attempt-code is deemed to have failed if it dies. If this argument is specified, then the coderef will determine whether the attempt-code is deemed to have failed (retry_if code returns true) or succeeded (retry_if code returns false).

  Coderef will be passed:

   \%h

  containing these keys:

   error
   action_retry
   attempt_result
   attempt_parameters

• non_blocking

  Boolean. If set to true, instead of delaying after a failure (or a success, depending on your backoff parameters), retry will immediately return. Then when called again it will immediately return (instead of retrying the attempt-code) until the required amount of delay has passed. To use this feature, you actually need to use the underlying OO code instead of the retry function:

   my $retry = Retry::Backoff->new(
       attempt_code => sub { ... },
       non_blocking => 1,
       ....
   );
   while (1) {
       # if the action failed, it doesn't sleep next time it's called, it won't do
       # anything until it's time to retry
       $action->run;
  
       # do something else while time goes on
   }

The rest of the arguments will be passed to the backoff strategy module (Algorithm::Backoff::*).

HOMEPAGE

Please visit the project's homepage at https://metacpan.org/release/Retry-Backoff.

SOURCE

Source repository is at https://github.com/perlancar/perl-Retry-Backoff.

SEE ALSO

Code is based on Action::Retry.

Other similar modules: Sub::Retry, Retry.

Backoff strategies are from Algorithm::Backoff::* modules.

AUTHOR

perlancar <perlancar@cpan.org>

CONTRIBUTOR

Dave Baird <dave@zerofive.co.uk>

CONTRIBUTING

To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

 % prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE

This software is copyright (c) 2024, 2019 by perlancar <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.

BUGS

Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=Retry-Backoff

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.

cpanm Retry::Backoff

perl -MCPAN -e shell
install Retry::Backoff