NAME

Parallel::Pipes - parallel processing using pipe(2) for communication and synchronization

SYNOPSIS

  use Parallel::Pipes;

  my $pipes = Parallel::Pipes->new(5, sub {
    # this is a worker code
    my $task = shift;
    my $result = do_work($task);
    return $result;
  });

  my $queue = Your::TaskQueue->new;
  # wrap Your::TaskQueue->get
  my $get; $get = sub {
    my $queue = shift;
    if (my @task = $queue->get) {
      return @task;
    }
    if (my @written = $pipes->is_written) {
      my @ready = $pipes->is_ready(@written);
      $queue->register($_->read) for @ready;
      return $queue->$get;
    } else {
      return;
    }
  };

  while (my @task = $queue->$get) {
    my @ready = $pipes->is_ready;
    $queue->register($_->read) for grep $_->is_written, @ready;
    my $min = List::Util::min($#task, $#ready);
    for my $i (0..$min) {
      # write tasks to pipes which are ready
      $ready[$i]->write($task[$i]);
    }
  }

  $pipes->close;

DESCRIPTION

NOTE: Parallel::Pipes provides low-level interfaces. If you are interested in using Parallel::Pipes, you may want to look at Parallel::Pipes::App instead, which provides more friendly interfaces.

Parallel processing is essential, but it is also difficult:

How can we synchronize our workers?

More precisely, how to detect our workers are ready or finished.

How can we communicate with our workers?

More precisely, how to collect results of tasks.

Parallel::Pipes tries to solve these problems with pipe(2) and select(2).

App::cpm, a fast CPAN module installer, uses Parallel::Pipes. Please look at App::cpm or eg directory for real world usages.

AUTHOR

Shoichi Kaji <skaji@cpan.org>

COPYRIGHT AND LICENSE

Copyright 2016 Shoichi Kaji <skaji@cpan.org>

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.