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Net::Server::PreForkSimple(3)  User Contributed Perl Documentation  Net::Server::PreForkSimple(3)

NAME
       Net::Server::PreForkSimple - Net::Server personality

SYNOPSIS
	 use Net::Server::PreForkSimple;
	 @ISA = qw(Net::Server::PreForkSimple);

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

	 __PACKAGE__->run();

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

       This personality binds to one or more ports and then forks "max_servers" child processes.
       The server will make sure that at any given time there are always "max_servers" available
       to receive a client request.  Each of these children will process up to "max_requests"
       client connections.  This type is good for a heavily hit site that can keep "max_servers"
       processes dedicated to the serving.  (Multi port accept defaults to 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,
       Net::Server::PreFork contains several other configurable parameters.

	 Key		   Value		   Default
	 max_servers	   \d+			   50
	 max_requests	   \d+			   1000

	 serialize	   (flock|semaphore|pipe)  undef
	 # serialize defaults to flock on multi_port or on Solaris
	 lock_file	   "filename"		   POSIX::tmpnam

	 check_for_dead    \d+			   30

	 max_dequeue	   \d+			   undef
	 check_for_dequeue \d+			   undef

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

       max_requests
	   The number of client connections to receive before a child terminates.

       serialize
	   Determines whether the server serializes child connections.	Options are undef, flock,
	   semaphore, or pipe.	Default is undef.  On multi_port servers or on servers running on
	   Solaris, the default is flock.  The flock option uses blocking exclusive flock on the
	   file specified in lock_file (see below).  The semaphore option uses IPC::Semaphore
	   (thanks to Bennett Todd) for giving some sample code.  The pipe option reads on a pipe
	   to choose the next.	the flock option should be the most bulletproof while the pipe
	   option should be the most portable.	(Flock is able to reliquish the block if the
	   process dies between accept on the socket and reading of the client connection -
	   semaphore and pipe do not)

       lock_file
	   Filename to use in flock serialized accept in order to serialize the accept sequece
	   between the children.  This will default to a generated temporary filename.	If
	   default value is used the lock_file will be removed when the server closes.

       check_for_dead
	   Seconds to wait before checking to see if a child died without letting the parent
	   know.

       max_dequeue
	   The maximum number of dequeue processes to start.  If a value of zero or undef is
	   given, no dequeue processes will be started.  The number of running dequeue processes
	   will be checked by the check_for_dead variable.

       check_for_dequeue
	   Seconds to wait before forking off a dequeue process.  The run_dequeue hook must be
	   defined when using this setting.  It is intended to use the dequeue process to take
	   care of items such as mail queues.  If a value of undef is given, no dequeue processes
	   will be started.

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
	 max_servers   80

	 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

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

PROCESS FLOW
       Process flow follows Net::Server until the loop phase.  At this point "max_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 always "max_servers" running.

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

       "$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->child_init_hook()"
	   This hook takes place immeditately after the child process forks from the parent and
	   before the child begins accepting connections.  It is intended for any addiotional
	   chrooting or other security measures.  It is suggested that all perl modules be used
	   by this point, so that the most shared memory possible is used.

       "$self->child_finish_hook()"
	   This hook takes place immediately before the child tells the parent that it is
	   exiting.  It is intended for saving out logged information or other general cleanup.

       "$self->run_dequeue()"
	   This hook only gets called in conjuction with the check_for_dequeue setting.

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::PreFork,
       Net::Server::MultiType, Net::Server::Single Net::Server::SIG Net::Server::Daemonize
       Net::Server::Proto

perl v5.12.1				    2007-03-26		    Net::Server::PreForkSimple(3)
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