Mojo::IOLoop::Subprocess(3pm) - Man pages

Mojo::IOLoop::SubproceUserpContributed Perl DocumMojo::IOLoop::Subprocess(3pm)

NAME
       Mojo::IOLoop::Subprocess - Subprocesses

SYNOPSIS
         use Mojo::IOLoop::Subprocess;

         # Operation that would block the event loop for 5 seconds
         my $subprocess = Mojo::IOLoop::Subprocess->new;
         $subprocess->run(
           sub ($subprocess) {
             sleep 5;
             return '♥', 'Mojolicious';
           },
           sub ($subprocess, $err, @results) {
             say "Subprocess error: $err" and return if $err;
             say "I $results[0] $results[1]!";
           }
         );

         # Operation that would block the event loop for 5 seconds (with promise)
         $subprocess->run_p(sub {
           sleep 5;
           return '♥', 'Mojolicious';
         })->then(sub (@results) {
           say "I $results[0] $results[1]!";
         })->catch(sub  {
           my $err = shift;
           say "Subprocess error: $err";
         });

         # Start event loop if necessary
         $subprocess->ioloop->start unless $subprocess->ioloop->is_running;

DESCRIPTION
       Mojo::IOLoop::Subprocess allows Mojo::IOLoop to perform computationally
       expensive operations in subprocesses, without blocking the event loop.

EVENTS
       Mojo::IOLoop::Subprocess inherits all events from Mojo::EventEmitter
       and can emit the following new ones.

   cleanup
         $subprocess->on(cleanup => sub ($subprocess) {...});

       Emitted in the subprocess right before the process will exit.

         $subprocess->on(cleanup => sub ($subprocess) { say "Process $$ is about to exit" });

   progress
         $subprocess->on(progress => sub ($subprocess, @data) {...});

       Emitted in the parent process when the subprocess calls the progress
       method.

   spawn
         $subprocess->on(spawn => sub ($subprocess) {...});

       Emitted in the parent process when the subprocess has been spawned.

         $subprocess->on(spawn => sub ($subprocess) {
           my $pid = $subprocess->pid;
           say "Performing work in process $pid";
         });

ATTRIBUTES
       Mojo::IOLoop::Subprocess implements the following attributes.

   deserialize
         my $cb      = $subprocess->deserialize;
         $subprocess = $subprocess->deserialize(sub {...});

       A callback used to deserialize subprocess return values, defaults to
       using Mojo::JSON.

         $subprocess->deserialize(sub ($bytes) { return [] });

   ioloop
         my $loop    = $subprocess->ioloop;
         $subprocess = $subprocess->ioloop(Mojo::IOLoop->new);

       Event loop object to control, defaults to the global Mojo::IOLoop
       singleton. Note that this attribute is weakened.

   serialize
         my $cb      = $subprocess->serialize;
         $subprocess = $subprocess->serialize(sub {...});

       A callback used to serialize subprocess return values, defaults to
       using Mojo::JSON.

         $subprocess->serialize(sub ($array) { return '' });

METHODS
       Mojo::IOLoop::Subprocess inherits all methods from Mojo::EventEmitter
       and implements the following new ones.

   exit_code
         my $code = $subprocess->exit_code;

       Returns the subprocess exit code, or "undef" if the subprocess is still
       running.

   pid
         my $pid = $subprocess->pid;

       Process id of the spawned subprocess if available.

   progress
         $subprocess->progress(@data);

       Send data serialized with Mojo::JSON to the parent process at any time
       during the subprocess's execution. Must be called by the subprocess and
       emits the "progress" event in the parent process with the data.

         # Send progress information to the parent process
         $subprocess->run(
           sub ($subprocess) {
             $subprocess->progress('0%');
             sleep 5;
             $subprocess->progress('50%');
             sleep 5;
             return 'Hello Mojo!';
           },
           sub ($subprocess, $err, @results) {
             say 'Progress is 100%';
             say $results[0];
           }
         );
         $subprocess->on(progress => sub ($subprocess, @data) { say "Progress is $data[0]" });

   run
         $subprocess = $subprocess->run(sub {...}, sub {...});

       Execute the first callback in a child process and wait for it to return
       one or more values, without blocking "ioloop" in the parent process.
       Then execute the second callback in the parent process with the
       results. The return values of the first callback and exceptions thrown
       by it, will be serialized with Mojo::JSON, so they can be shared
       between processes.

   run_p
         my $promise = $subprocess->run_p(sub {...});

       Same as "run", but returns a Mojo::Promise object instead of accepting
       a second callback.

         $subprocess->run_p(sub {
           sleep 5;
           return '♥', 'Mojolicious';
         })->then(sub (@results) {
           say "I $results[0] $results[1]!";
         })->catch(sub ($err) {
           say "Subprocess error: $err";
         })->wait;

SEE ALSO
       Mojolicious, Mojolicious::Guides, <https://mojolicious.org>.

perl v5.36.0                      2022-12-22     Mojo::IOLoop::Subprocess(3pm)

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