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Net::Server::PreForkSiUmspelre(C3o)ntributed
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).
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.
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
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