Jan Seidl
and 2 contributors

NAME

Continual::Process - (re)start dead process

SYNOPSIS

    use Continual::Process;
    use Continual::Process::Loop;

    my $loop = Continual::Process::Loop->new(
        instances => [
            Continual::Process->new(
                name => 'job1',
                code => sub {
                    my $pid = fork;
                    if ($pid) {
                        return $pid;
                    }

                    say "Hello world";
                    sleep 5;
                    say "Bye, bye world";

                    exit 1;
                },
                instances => 4,
            )->create_instance(),
            Continual::Process->new(
                name => 'job2',
                code => sub {
                    my $pid = fork;
                    if ($pid) {
                        return $pid;
                    }

                    exec 'perl -ne "sleep 1"';

                    exit 1;
                },
            )->create_instance(),
        ]
    );

    $loop->run();

DESCRIPTION

Continual::Process with Continual::Process::Loop is a way how to run a process forever.

Continual::Process creates Continual::Process::Instance which runs in a loop and if it dies, it starts again.

The code for starting a process is OS-agnostic. The only condition is that the code must return PID of the new process.

loop

Continual::Process supports more loops:

Continual::Process::Loop::Simple - simple while/sleep loop
Continual::Process::Loop::AnyEvent - AnyEvent support
Continual::Process::Loop::Mojo - Mojo::IOLoop support

METHODS

new(%attributes)

%attributes

name

name of process (only for identification)

code

CodeRef which start new process and returned PID of new process

code-sub must return PID of the new process or die!

for example Linux and fork:

    code => sub {
        if (my $pid  = fork) {
            return $pid;
        }

        ...

        exit 1;
    }

or Windows and Win32::Process

    code => sub {
        my ($instance) = @_;

        Win32::Process::Create(
            $ProcessObj,
            "C:\\winnt\\system32\\notepad.exe",
            "notepad temp.txt",
            0,
            NORMAL_PRIORITY_CLASS,
            "."
        ) || die "Process ".$instance->name." start fail: ".$^E;

        return $ProcessObj->GetProcessID();
    }

best way is use Continual::Process::Helper prepare_fork or prepare_run method

instances

count of running instances

default 1

create_instance()

create and return list of Continual::Process::Instance

LICENSE

Copyright (C) Avast Software.

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

AUTHOR

Jan Seidl <seidl@avast.com>