NAME

Mojo::IOLoop::ReadWriteFork - Fork a process and read/write from it

VERSION

0.22

SYNOPSIS

  my $fork = Mojo::IOLoop::ReadWriteFork->new;

  # Emitted if something terrible happens
  $fork->on(error => sub { my ($fork, $error) = @_; warn $error; });

  # Emitted when the child completes
  $fork->on(close => sub { my ($fork, $exit_value, $signal) = @_; Mojo::IOLoop->stop; });

  # Emitted when the child prints to STDOUT or STDERR
  $fork->on(read => sub {
    my ($fork, $buf) = @_;
    print qq(Child process sent us "$buf");
  });

  # Need to set "conduit" for bash, ssh, and other programs that require a pty
  $fork->conduit({type => "pty"});

  # Start the application
  $fork->run("bash", -c => q(echo $YIKES foo bar baz));

See also https://github.com/jhthorsen/mojo-ioloop-readwritefork/tree/master/example/tail.pl for an example usage from a Mojo::Controller.

DESCRIPTION

This class enable you to fork a child process and "read" and "write" data to. You can also send signals to the child and see when the process ends. The child process can be an external program (bash, telnet, ffmpeg, ...) or a CODE block running perl.

Patches that enable the "read" event to see the difference between STDERR and STDOUT are more than welcome.

EVENTS

close

  $self->on(close => sub { my ($self, $exit_value, $signal) = @_; });

Emitted when the child process exit.

error

  $self->on(error => sub { my ($self, $str) = @_; });

Emitted when when the there is an issue with creating, writing or reading from the child process.

fork

  $self->on(fork => sub { my ($self) = @_; });

Emitted after fork() has been called. Note that the child process might not yet have been started. The order of things is impossible to say, but it's something like this:

            .------.
            | fork |
            '------'
               |
           ___/ \_________________
          |                       |
          | (parent)              | (child)
      .-------------.             |
      | emit "fork" |    .--------------------.
      '-------------'    | set up filehandles |
                         '--------------------'
                                  |
                          .---------------.
                          | exec $program |
                          '---------------'

See also "pid" for example usage of this event.

read

  $self->on(read => sub { my ($self, $buf) = @_; });

Emitted when the child has written a chunk of data to STDOUT or STDERR.

ATTRIBUTES

conduit

  $hash = $self->conduit;
  $self = $self->conduit({type => "pipe"});

Used to set the conduit and conduit options. Example:

  $self->conduit({raw => 1, type => "pty"});

ioloop

  $ioloop = $self->ioloop;
  $self = $self->ioloop(Mojo::IOLoop->singleton);

Holds a Mojo::IOLoop object.

pid

  $int = $self->pid;

Holds the child process ID. Note that "start" will start the process after the IO loop is started. This means that the code below will not work:

  $fork->run("bash", -c => q(echo $YIKES foo bar baz));
  warn $fork->pid; # pid() is not yet set

This will work though:

  $fork->on(spawn => sub { my $self = shift; warn $self->pid });
  $fork->run("bash", -c => q(echo $YIKES foo bar baz));

METHODS

close

  $self = $self->close("stdin");

Close STDIN stream to the child process immediately.

run

  $self = $self->run($program, @program_args);
  $self = $self->run(\&Some::Perl::function, @function_args);

Simpler version of "start". Can either start an application or run a perl function.

start

  $self = $self->start(\%args);

Used to fork and exec a child process. %args can have:

• program

  Either an application or a CODE ref.

• program_args

  A list of options passed on to "program" or as input to the CODE ref.

  Note that this module will start "program" with this code:

    exec $program, @$program_args;

  This means that the code is subject for shell injection unless invoked with more than one argument. This is considered a feature, but something you should be avare of. See also "exec" in perlfunc for more details.

• env

  Passing in env will override the default set of environment variables, stored in %ENV.

• conduit

  Either "pipe" (default) or "pty". "pty" will use IO::Pty to simulate a "pty", while "pipe" will just use "pipe" in perlfunc. This can also be specified by using the "conduit" attribute.

• clone_winsize_from

  See "clone_winsize_from" in IO::Pty. This only makes sense if "conduit" is set to "pty". This can also be specified by using the "conduit" attribute.

• raw

  See "set_raw" in IO::Pty. This only makes sense if "conduit" is set to "pty". This can also be specified by using the "conduit" attribute.

write

  $self = $self->write($chunk);
  $self = $self->write($chunk, $cb);

Used to write data to the child process STDIN. An optional callback will be called once STDIN is drained.

Example:

  $self->write("some data\n", sub {
    my ($self) = @_;
    $self->close;
  });

kill

  $bool = $self->kill;
  $bool = $self->kill(15); # default

Used to signal the child.

SEE ALSO

Mojo::IOLoop::ForkCall.

https://github.com/jhthorsen/mojo-ioloop-readwritefork/tree/master/example/tail.pl

COPYRIGHT AND LICENSE

Copyright (C) 2013-2016, Jan Henning Thorsen

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.

AUTHOR

Jan Henning Thorsen - jhthorsen@cpan.org

cpanm Mojo::IOLoop::ReadWriteFork

perl -MCPAN -e shell
install Mojo::IOLoop::ReadWriteFork