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.