Net::Server::PreForkSiUser(Contributed Perl DocumNet::Server::PreForkSimple(3)NAMENet::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 personal-
ity, 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 parame-
ters.
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 termi-
nates.
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 let-
ting 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 mea-
sures. It is suggested that all perl modules be used by this
point, so that the most shared memory possible is used.
"$self->child_finish_hook()"
This hook takes place immediately before the child tells the parent
that it is exiting. It is intended for saving out logged informa-
tion or other general cleanup.
"$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 wel-
come.
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::Pre-
Fork, Net::Server::MultiType, Net::Server::Single Net::Server::SIG
Net::Server::Daemonize Net::Server::Proto
perl v5.8.8 2007-02-03 Net::Server::PreForkSimple(3)
