net::server::fork(3pm) [debian man page]
Net::Server::Fork(3pm) User Contributed Perl Documentation Net::Server::Fork(3pm) NAME
Net::Server::Fork - Net::Server personality SYNOPSIS
use base qw(Net::Server::Fork); 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 waits for a client connection. When a connection is received, the server forks a child. The child handles the request and then closes. With the exception of parent/child signaling, this module will work (with basic functionality) on Win32 systems. ARGUMENTS
check_for_dead Number of seconds to wait before looking for dead children. This only takes place if the maximum number of child processes (max_servers) has been reached. Default is 60 seconds. max_servers The maximum number of children to fork. The server will not accept connections until there are free children. Default is 256 children. 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. 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
See Net::Server. PROCESS FLOW
Process flow follows Net::Server until the post_accept phase. At this point a child is forked. The parent is immediately able to wait for another request. The child handles the request and then exits. HOOKS
The Fork server has the following hooks in addition to the hooks provided by the Net::Server base class. See Net::Server "$self->child_init_hook()" This hook is called just after the fork and after signals have been cleaned up. "$self->pre_accept_hook()" This hook occurs just before the accept is called. "$self->pre_fork_hook()" This hook occurs just after accept but before the fork. "$self->post_accept_hook()" This hook occurs in the child after the accept and fork. "$self->run_dequeue()" This hook only gets called in conjunction with the check_for_dequeue setting. HOT DEPLOY
Since version 2.000, the Fork server has accepted the TTIN and TTOU signals. When a TTIN is received, the max_servers is increased by 1. If a TTOU signal is received the max_servers is decreased by 1. This allows for adjusting the number of handling processes without having to restart the server. AUTHOR
Paul Seamons <paul@seamons.com> Rob Brown <bbb@cpan.org> SEE ALSO
Please see also Net::Server::INET, Net::Server::PreFork, Net::Server::MultiType, Net::Server::SIG Net::Server::Single perl v5.14.2 2013-11-28 Net::Server::Fork(3pm)
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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 base 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|none) undef # serialize defaults to flock on multi_port or on Solaris lock_file "filename" File::Temp::tempfile or 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, pipe, or none. 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). An option of none will not perform any serialization. If "none" is passed and there are multiple ports then a the default serialization will be used insted of "none." 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. "$self->run_dequeue()" This hook only gets called in conjunction with the check_for_dequeue setting. "$self->idle_loop_hook()" This hook is called in every pass through the main process wait loop. HOT DEPLOY
Since version 2.000, the PreForkSimple server has accepted the TTIN and TTOU signals. When a TTIN is received, the max_servers is increased by 1. If a TTOU signal is received the max_servers is decreased by 1. This allows for adjusting the number of handling processes without having to restart the server. 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 v5.18.2 2013-01-09 Net::Server::PreForkSimple(3)