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Net::Server::PreFork(3User Contributed Perl DocumentatiNet::Server::PreFork(3)

NAME
       Net::Server::PreFork - Net::Server personality

SYNOPSIS
	   use base qw(Net::Server::PreFork);

	   sub process_request {
	       #...code...
	   }

	   __PACKAGE__->run();

DESCRIPTION
       Please read the pod on Net::Server and Net::Server::PreForkSimple
       first.  This module is a	personality, or	extension, or sub class, of
       the Net::Server::PreForkSimple class which is a sub class of
       Net::Server.  See Net::Server::PreForkSimple.

       This personality	binds to one or	more ports and then forks
       "min_servers" child process.  The server	will make sure that at any
       given time there	are "min_spare_servers"	available to receive a client
       request,	up to "max_servers".  Each of these children will process up
       to "max_requests" client	connections.  This type	is good	for a heavily
       hit site, and should scale well for most	applications.  (Multi port
       accept is accomplished using flock to serialize the children).

       At this time, it	does not appear	that this module will pass tests on
       Win32 systems.  Any ideas or patches for	making the tests pass would be
       welcome.

SAMPLE CODE
       Please see the sample listed in Net::Server.

COMMAND	LINE ARGUMENTS
       In addition to the command line arguments of the	Net::Server base class
       and the Net::Server::PreForkSimple parent class,	Net::Server::PreFork
       contains	several	other configurable parameters.	You really should also
       see Net::Server::PreForkSimple.

	   Key		       Value		       Default
	   min_servers	       \d+		       5
	   min_spare_servers   \d+		       2
	   max_spare_servers   \d+		       10
	   max_servers	       \d+		       50
	   max_requests	       \d+		       1000

	   serialize	       (flock|semaphore
				|pipe|none)	       undef
	   # serialize defaults	to flock on multi_port or on Solaris
	   lock_file	       "filename"	       File::Temp->new

	   check_for_dead      \d+		       30
	   check_for_waiting   \d+		       10

	   max_dequeue	       \d+		       undef
	   check_for_dequeue   \d+		       undef

	   child_communication 1		       undef

       min_servers
	   The minimum number of servers to keep running.

       min_spare_servers
	   The minimum number of servers to have waiting for requests.
	   Minimum and maximum numbers should not be set to close to each
	   other or the	server will fork and kill children too often.

       max_spare_servers
	   The maximum number of servers to have waiting for requests.	See
	   min_spare_servers.

       max_servers
	   The maximum number of child servers to start.  This does not	apply
	   to dequeue processes.

       check_for_waiting
	   Seconds to wait before checking to see if we	can kill off some
	   waiting servers.

       check_for_spawn
	   Seconds between checking to see if we need to spawn more children

       min_child_ttl
	   Minimum number of seconds between starting children and killing a
	   child process

       child_communication
	   Enable child	communication to parent	via unix sockets.  If set to
	   true, will let children write to the	socket contained in
	   $self->{'server'}->{'parent_sock'}.	The parent will	be notified
	   through child_is_talking_hook where the first argument is the
	   socket to the child.	 The child's socket is stored in
	   $self->{'server'}->{'children'}->{$child_pid}->{'sock'}.

       serialize
	   See the documentation under Net::Server::PreForkSimple.

CONFIGURATION FILE
       "Net::Server::PreFork" allows for the use of a configuration file to
       read in server parameters.  The format of this conf file	is simple key
       value pairs.  Comments and white	space are ignored.

	   #-------------- file	test.conf --------------

	   ### server information
	   min_servers	 20
	   max_servers	 80
	   min_spare_servers 10
	   min_spare_servers 15

	   max_requests	 1000

	   ### user and	group to become
	   user	       somebody
	   group       everybody

	   ### logging ?
	   log_file    /var/log/server.log
	   log_level   3
	   pid_file    /tmp/server.pid

	   ### access control
	   allow       .+\.(net|com)
	   allow       domain\.com
	   deny	       a.+

	   ### background the process?
	   background  1

	   ### ports to	bind
	   host	       127.0.0.1
	   port	       localhost:20204
	   port	       20205

	   ### reverse lookups ?
	   # reverse_lookups on

	   ### enable child communication ?
	   # child_communication

	   #-------------- file	test.conf --------------

PROCESS	FLOW
       Process flow follows Net::Server	until the loop phase.  At this point
       "min_servers" are forked	and wait for connections.  When	a child
       accepts a connection, finishs processing	a client, or exits, it relays
       that information	to the parent, which keeps track and makes sure	there
       are enough children to fulfill "min_servers", "min_spare_servers",
       "max_spare_servers", and	"max_servers".

HOOKS
       The PreFork server has the following hooks in addition to the hooks
       provided	by PreForkSimple.  See Net::Server::PreForkSimple.

       "$self->run_n_children_hook()"
	   This	hook occurs at the top of run_n_children which is called each
	   time	the server goes	to start more child processes.	This gives the
	   parent to do	a little of its	own accountting	(as desired).  Idea
	   for this hook came from James FitzGibbon.

       "$self->parent_read_hook()"
	   This	hook occurs any	time that the parent reads information from
	   the child.  The line	from the child is sent as an argument.

       "$self->child_is_talking_hook()"
	   This	hook occurs if child_communication is true and the child has
	   written to $self->{'server'}->{'parent_sock'}.  The first argument
	   will	be the open socket to the child.

       "$self->idle_loop_hook()"
	   This	hook is	called in every	pass through the main process wait
	   loop, every "check_for_waiting" seconds.  The first argument	is a
	   reference to	an array of file descriptors that can be read at the
	   moment.

       "$self->cleanup_dead_child_hook(	$child )"
	   This	hook is	called when a dead child is detected.  A child is
	   considered dead when	the pid	does no	longer exist.  This hook could
	   be used to cleanup possible temporary files or locks	left over by a
	   dead	child.	=back

HOT DEPLOY
       Since version 2.000, the	PreFork	server has accepted the	TTIN and TTOU
       signals.	 When a	TTIN is	received, the min and max_servers are
       increased by 1.	If a TTOU signal is received the min max_servers are
       decreased by 1.	This allows for	adjusting the number of	handling
       processes without having	to restart the server.

BUGS
       Tests don't seem	to work	on Win32.  Any ideas or	patches	would be
       welcome.

TO DO
       See Net::Server

AUTHOR
       Paul T. Seamons paul@seamons.com

THANKS
       See Net::Server

SEE ALSO
       Please see also Net::Server::Fork, Net::Server::INET,
       Net::Server::PreForkSimple, Net::Server::MultiType, Net::Server::Single
       Net::Server::SIG	Net::Server::Daemonize Net::Server::Proto

POD ERRORS
       Hey! The	above document had some	coding errors, which are explained
       below:

       Around line 683:
	   You forgot a	'=back'	before '=head1'

perl v5.32.0			  2017-08-10	       Net::Server::PreFork(3)

NAME | SYNOPSIS | DESCRIPTION | SAMPLE CODE | COMMAND LINE ARGUMENTS | CONFIGURATION FILE | PROCESS FLOW | HOOKS | HOT DEPLOY | BUGS | TO DO | AUTHOR | THANKS | SEE ALSO | POD ERRORS

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