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

NAME

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

SYNOPSIS

	 use Net::Server::PreFork;
	 @ISA = 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)  undef
	 # serialize defaults to flock on multi_port or on Solaris
	 lock_file	     "filename" 	     POSIX::tmpnam

	 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.

       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}.

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.

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

perl v5.12.1							    2007-03-23						   Net::Server::PreFork(3)