NAME¶
Parallel::Prefork::SpareWorkers - A prefork server framework with support for
(min|max)spareservers
SYNOPSIS¶
use Parallel::Prefork::SpareWorkers qw(:status);
my $pm = Parallel::Prefork::SpareWorkers->new({
max_workers => 40,
min_spare_workers => 5,
max_spare_workers => 10,
trap_signals => {
TERM => 'TERM',
HUP => 'TERM',
USR1 => undef,
},
});
while ($pm->signal_received ne 'TERM') {
load_config();
$pm->start and next;
# do what ever you like, as follows
while (my $sock = $listener->accept()) {
$pm->set_status('A');
...
$sock->close();
$pm->set_status(STATUS_IDLE);
}
$pm->finish;
}
$pm->wait_all_children;
DESCRIPTION¶
"Parallel::Prefork::SpareWorkers" is a subclass of
"Parallel::Prefork" that supports setting minimum and maximum number
of spare worker processes, a feature commonly found in network servers. The
module adds to "Parallel::Prefork" several initialization
parameters, constants, and a method to set state of the worker processes.
METHODS¶
new¶
Instantiation. "Parallel::Prefork::ShpareWorkers" recognizes the
following parameters in addition to those defined by
"Parallel::Prefork". The parameters can be accessed using accessors
with same names as well.
min_spare_workers
minimum number of spare workers (mandatory)
max_spare_workers
maxmum number of spare workers (default: max_workers)
heartbeat
a fractional period (in seconds) of child amount checking. Do not use very small
numbers to avoid frequent use of CPU (default: 0.25)
scoreboard_file
filename of scoreboard. If not set, "Parallel::Prefork::SpareWorkers"
will create a temporary file.
set_status¶
sets a single-byte character state of the worker process. Worker processes
should set any character of their choice using the function (but not one of
the reserved characters) to declare that it is running some kind of task. Or
the state should be set to "STATUS_IDLE" '_' once the worker enters
idle state. The other reserved character is "STATUS_NEXIST" '.'
which should never be set directly by applications.
CONSTANTS¶
STATUS_NEXIST¶
scoreboard status character '.', meaning no worker process is assigned to the
slot of the scoreboard. Applications should never set this value directly.
STATUS_IDLE¶
scoreboard status character '_', meaning that a worker process is in idle state
LICENSE¶
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
See
http://www.perl.com/perl/misc/Artistic.html