As long as your job fails and there are retries left, sleep and then try the job again. We can write this as follows: 
    sub retry {
        my $job     = shift;
        my $retries = shift || 1;
        my $delay   = shift || 1;
        my $res;
        sleep $delay while !($res = &$job) && --$retries;
        return $res;
    }

[download]
(I renamed $timeout to $delay, which more accurately describes what it is. A timeout is usually the maximum time that you're willing to let an operation proceed before giving up and canceling it.)

Just to be safe, let's test our code with Test::More: 

    use Test::More tests => 5;

    is( retry(sub{0}), 0
      , "always-failing job fails 1 retry" );
    is( retry(sub{0}, 2), 0
      , "always-failing job fails 2 retries" );
    is( retry(sub{1}, 0), 1
      , "always-succeeding job succeeds regardless of retries" );
    is( retry(mk_counter(), 1), 0
      , "succeed-on-second job fails if given only 1 retry" );
    is( retry(mk_counter(), 2), 1
      , "succeed-on-second job succeeds if given 2 retries" );


    # helper that makes fns that return 0 on 1st call, 1 on 2nd, ...

    sub mk_counter {
        my $i = 0;
        sub { $i++ }
    }

[download]
And the test results: 
    1..5
    ok 1 - always-failing job fails 1 retry
    ok 2 - always-failing job fails 2 retries
    ok 3 - always-succeeding job succeeds regardless of retries
    ok 4 - succeed-on-second job fails if given only 1 retry
    ok 5 - succeed-on-second job succeeds if given 2 retries

[download]

Cheers,
Tom

Tom Moertel : Blog / Talks / CPAN / LectroTest / PXSL / Coffee / Movie Rating Decoder

In reply to Re: retry code snippet by tmoertel
in thread retry code snippet by ccn

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