Mojo::IOLoop::Subprocess(3)
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 'aY', '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 'aY', '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 'aY', 'Mojolicious';
})->then(sub (@results) {
say "I $results[0] $results[1]!";
})->catch(sub ($err) {
say "Subprocess error: $err";
})->wait;
SEE ALSO
Mojolicious(3), Mojolicious::Guides(3), <https://mojolicious.org>.
perl v5.32.1 2021-12-08 Mojo::IOLoop::Subprocess(3)
mojolicious 9.260.0 - Generated Mon May 30 14:19:52 CDT 2022