NAME
    Retry

SYNOPSIS
    A one-feature module, this provides a method to wrap any function in
    automatic retry logic, with exponential back-off delays, and a callback
    for each time an attempt fails.

    Example:

      use Retry;
      use Try::Tiny;
      use LWP::UserAgent;

      my $code_to_retry = sub {
        my $r = LWP::UserAgent->new->get("http://example.com");
        die $r->status_line unless $r->is_success;
        return $r;
      };

      my $agent = Retry->new(
        # This callback is optional:
        failure_callback => sub { warn "Transient error: " . $_[0]; },
      );

      try {
        $agent->retry($code_to_retry)
      }
      catch {
        warn "All attempts failed: $_";
      };

ATTRIBUTES
  retry_delay
    This is the initial delay used when the routine failed, before retrying
    again.

    Every subsequent failure doubles the amount.

    It defaults to 8 seconds.

  max_retry_attempts
    The maximum number of retries we should attempt before giving up
    completely.

    It defaults to 5.

  failure_callback
    Optional. To be notified of *every* failure (even if we eventually
    succeed on a later retry), install a subroutine callback here.

    For example:

      Retry->new(
          failure_callback => sub { warn "failed $count++ times" }
      );

METHODS
  retry
    Its purpose is to execute the passed subroutine, over and over, until it
    succeeds, or the number of retries is exceeded. The delay between
    retries increases exponentially. (Failure is indicated by the sub dying)

    If the subroutine succeeds, then its scalar return value will be
    returned by retry.

    For example, you could replace this:

      my $val = unreliable_web_request();

    With this:

       my $val = Retry->new->retry(
           sub { unreliable_web_request() }
       );

AUTHOR
    Toby Corkindale -- https://github.com/TJC/

LICENSE
    This module is released under the Perl Artistic License 2.0:
    <http://www.perlfoundation.org/artistic_license_2_0>

    It is based upon source code which is Copyright 2010 Strategic Data Pty
    Ltd, however it is used and released with permission.

SEE ALSO
    Attempt

    Retry differs from Attempt in having exponentially increasing delays,
    and by having a callback inbetween attempts.

    However Attempt has a simpler syntax.