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lib/Acme/Ghost/Prefork.pm  view on Meta::CPAN

package Acme::Ghost::Prefork;
use warnings;
use strict;
use utf8;

=encoding utf-8

=head1 NAME

Acme::Ghost::Prefork - Pre-forking ghost daemon

=head1 SYNOPSIS

    use Acme::Ghost::Prefork;

    my $g = Acme::Ghost::Prefork->new(
        logfile => '/tmp/daemon.log',
        pidfile => '/tmp/daemon.pid',
        spirit => sub {
            my $self = shift;
            my $max = 10;
            my $i = 0;
            while ($self->tick) {
                $i++;
                sleep 1;
                $self->log->debug(sprintf("$$> %d/%d", $i, $max));
                last if $i >= $max;
            }
        },
    );

    exit $g->ctrl(shift(@ARGV) // '');

=head1 DESCRIPTION

Pre-forking ghost daemon (server)

=head1 ATTRIBUTES

This class inherits all attributes from L<Acme::Ghost> and implements the following new ones

=head2 graceful_timeout

    graceful_timeout => 120

The maximum amount of time in seconds stopping a spirit gracefully may take before being forced to stop

B<Note that> this value should usually be a little larger than the maximum
amount of time you expect any one request to take

Defaults to C<120>

=head2 heartbeat_interval

    heartbeat_interval => 5

Heartbeat interval in seconds, defaults to C<5>

=head2 heartbeat_timeout

    heartbeat_timeout => 50

Maximum amount of time in seconds before a spirit without a heartbeat will be stopped gracefully

B<Note that> this value should usually be a little larger than the maximum
amount of time you expect any one operation to block the event loop

Defaults to C<50>

=head2 spare

    spare => 2

Temporarily spawn up to this number of additional spirits if there is a need

This allows for new spirits to be started while old ones are still shutting down gracefully,
drastically reducing the performance cost of spirit restarts.

Defaults to C<2>

=head2 spirits, workers

    spirits => 4

Number of spirit processes.

A good rule of thumb is two spirit processes per CPU core for applications that perform mostly
non-blocking operations.
Blocking operations often require more amount of spirits and benefit from decreasing concurrency
(often as low as C<1>)

Defaults to C<4>

=head1 METHODS

This class inherits all methods from L<Acme::Ghost> and implements the following new ones

=head2 again

This method is called immediately after creating the instance and returns it

B<NOTE:> Internal use only!

=head2 healthy

    my $healthy = $g->healthy;

This method returns the number of currently active live spirit processes (with a heartbeat)

=head2 startup

    $prefork->startup;

This method starts preforked process (manager and spirits) and wait for L</"MANAGER SIGNALS">

=head2 tick