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::PreFork);
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 connectionsemaphore
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 -------------PROCESS
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
"$self->child_init_hook()"
This hook takes place immeditately after the child process forks from the parent and before the
child begins accepting connections. It is intended for any addiotional chrooting or other
security measures. It is suggested that all perl modules be used by this point, so that the most
shared memory possible is used.
"$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
perl v5.8.8 2003-03-29 Net::Server::PreForkSimple(3)
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