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.