NAME

       Algorithm::Backoff - Various backoff strategies for retry

VERSION

       This document describes version 0.009 of Algorithm::Backoff (from Perl distribution
       Algorithm-Backoff), released on 2019-06-20.

SYNOPSIS

        # 1. pick a strategy and instantiate

        use Algorithm::Backoff::Constant;
        my $ab = Algorithm::Backoff::Constant->new(
            delay             => 2, # required
            #delay_on_success => 0, # optional, default 0
        );

        # 2. log success/failure and get a new number of seconds to delay, timestamp is
        # optional but must be monotonically increasing.

        my $secs = $ab->failure(); # => 2
        my $secs = $ab->success(); # => 0
        my $secs = $ab->failure(); # => 2

DESCRIPTION

       This distribution provides several classes that implement various backoff strategies for
       setting delay between retry attempts.

       This class ("Algorithm::Backoff") is a base class only.

METHODS

   new
       Usage:

        new(%args) -> obj

       This function is not exported.

       Arguments ('*' denotes required arguments):

       •   jitter_factor => float

           How much to add randomness.

           If you set this to a value larger than 0, the actual delay will be between a random
           number between original_delay * (1-jitter_factor) and original_delay *
           (1+jitter_factor). Jitters are usually added to avoid so-called "thundering herd"
           problem.

           The jitter will be applied to delay on failure as well as on success.

       •   max_attempts => uint (default: 0)

           Maximum number consecutive failures before giving up.

           0 means to retry endlessly without ever giving up. 1 means to give up after a single
           failure (i.e. no retry attempts). 2 means to retry once after a failure.  Note that
           after a success, the number of attempts is reset (as expected). So if max_attempts is
           3, and if you fail twice then succeed, then on the next failure the algorithm will
           retry again for a maximum of 3 times.

       Return value:  (obj)

   success
       Usage:

        my $secs = $obj->success([ $timestamp ]);

       Log a successful attempt. If not specified, $timestamp defaults to current time. Will
       return the suggested number of seconds to wait before doing another attempt.

   failure
       Usage:

        my $secs = $obj->failure([ $timestamp ]);

       Log a failed attempt. If not specified, $timestamp defaults to current time.  Will return
       the suggested number of seconds to wait before doing another attempt, or -1 if it suggests
       that one gives up (e.g. if "max_attempts" parameter has been exceeded).

HOMEPAGE

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

SOURCE

       Source repository is at <https://github.com/perlancar/perl-Algorithm-Backoff>.

BUGS

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

SEE ALSO

       Retry::Backoff - an application of Algorithm::Backoff to retry a piece of code using
       various backoff strategies.

       App::AlgorithmBackoffUtils - various CLI's related to Algorithm::Backoff.

       Action::Retry - Somehow I didn't find this module before writing Algorithm::Backoff.
       Otherwise I probably would not have created Algorithm::Backoff. But Algorithm::Backoff
       offers an alternative interface, some additional parameters (like delay on success and
       jitter factor), a lighter footprint (no Moo), and a couple more strategies.

AUTHOR

       perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2019 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.