#!/usr/bin/env perl

use v5.10;
use strict;
use warnings;
use Redis::Client;

my $queue    = 'queue:jobs';    # Name of the queue in redis
my $fail     = 'queue:fail';    # Queue with all the failed jobs
my $timeout  = 60;               # Timeout for the single job run time
my $wait     = 5;                # Timer for the running tasks
my $runnable = 1;                # Variable for job looping

# We might loose a job when this job is terminated with Ctrl-C.
# So let's catch the signals and shutdown the jobrunner after
# a full run is completed.

sub INT_handler {

  # Setting the value for the while loop to false == 0
  # so the while loop will terminate after the run
  warn "Shutdown requested - please wait until job is completed.\n";
  $runnable = 0;
}

$SIG{'INT'} = 'INT_handler';

# Instantiate a Redis::Client object
my $client = Redis::Client->new(host => 'localhost', port => 6379);


# This loop will run forever
while ($runnable) {

  say "Jobrunner is active";

  # Get an element from the workqueue or wait until there
  # is one available
  # (You might want to use a timeout to see if your worker
  # is still runnning = $wait );
  #
  # Please note: We are getting an element, if we fail we put
  # it back in the fail queue
  my ($list, $job) = $client->blpop($queue, $wait);
  $job // next;

  eval {
    local $SIG{ALRM} = sub {
      die "Timeout for job ($job)\n";
    };
    alarm $timeout;

    # do your job workload here! - probably call something,
    # do some video encoding, whatever you like
    # Please remember: Your job will get killed after $wait!
    say "I have a job";

    alarm 0;
  };

  # Check if we ran into an error
  if ($@) {

    say "Job fail ($job)";

    # Let's catch some errors - add more if you know more fail
    # reasons for your job runner.
    given ($@) {
      when (/^Timeout/) { warn "Job got a timeout\n"; }
      default           { warn "Job failed. Reason($@)\n"; }
    }

    # Let's push the failed job to a fail queue
    $client->rpush($fail => $job);

  }
  else {

    # The job succeeded - nothing to do here
    say "Job success ($job)";
  }

}    # end of while