Net::Server::PreForkSimple(3pm)

1Net::Server::PreForkSimUpsleer(3C)ontributed Perl DocumeNnetta:t:iSoenrver::PreForkSimple(3)
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NAME

6       Net::Server::PreForkSimple - Net::Server personality
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SYNOPSIS

9         use Net::Server::PreForkSimple;
10         @ISA = qw(Net::Server::PreForkSimple);
11
12         sub process_request {
13            #...code...
14         }
15
16         __PACKAGE__->run();
17

DESCRIPTION

19       Please read the pod on Net::Server first.  This module is a
20       personality, or extension, or sub class, of the Net::Server module.
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22       This personality binds to one or more ports and then forks
23       "max_servers" child processes.  The server will make sure that at any
24       given time there are always "max_servers" available to receive a client
25       request.  Each of these children will process up to "max_requests"
26       client connections.  This type is good for a heavily hit site that can
27       keep "max_servers" processes dedicated to the serving.  (Multi port
28       accept defaults to using flock to serialize the children).
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30       At this time, it does not appear that this module will pass tests on
31       Win32 systems.  Any ideas or patches for making the tests pass would be
32       welcome.
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SAMPLE CODE

35       Please see the sample listed in Net::Server.
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COMMAND LINE ARGUMENTS

38       In addition to the command line arguments of the Net::Server base
39       class, Net::Server::PreFork contains several other configurable
40       parameters.
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42         Key               Value                   Default
43         max_servers       \d+                     50
44         max_requests      \d+                     1000
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46         serialize         (flock|semaphore|pipe)  undef
47         # serialize defaults to flock on multi_port or on Solaris
48         lock_file         "filename"              POSIX::tmpnam
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50         check_for_dead    \d+                     30
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52         max_dequeue       \d+                     undef
53         check_for_dequeue \d+                     undef
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55       max_servers
56           The maximum number of child servers to start and maintain.  This
57           does not apply to dequeue processes.
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59       max_requests
60           The number of client connections to receive before a child
61           terminates.
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63       serialize
64           Determines whether the server serializes child connections.
65           Options are undef, flock, semaphore, or pipe.  Default is undef.
66           On multi_port servers or on servers running on Solaris, the default
67           is flock.  The flock option uses blocking exclusive flock on the
68           file specified in lock_file (see below).  The semaphore option uses
69           IPC::Semaphore (thanks to Bennett Todd) for giving some sample
70           code.  The pipe option reads on a pipe to choose the next.  the
71           flock option should be the most bulletproof while the pipe option
72           should be the most portable.  (Flock is able to reliquish the block
73           if the process dies between accept on the socket and reading of the
74           client connection - semaphore and pipe do not)
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76       lock_file
77           Filename to use in flock serialized accept in order to serialize
78           the accept sequece between the children.  This will default to a
79           generated temporary filename.  If default value is used the
80           lock_file will be removed when the server closes.
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82       check_for_dead
83           Seconds to wait before checking to see if a child died without
84           letting the parent know.
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86       max_dequeue
87           The maximum number of dequeue processes to start.  If a value of
88           zero or undef is given, no dequeue processes will be started.  The
89           number of running dequeue processes will be checked by the
90           check_for_dead variable.
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92       check_for_dequeue
93           Seconds to wait before forking off a dequeue process.  The
94           run_dequeue hook must be defined when using this setting.  It is
95           intended to use the dequeue process to take care of items such as
96           mail queues.  If a value of undef is given, no dequeue processes
97           will be started.
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CONFIGURATION FILE

100       "Net::Server::PreFork" allows for the use of a configuration file to
101       read in server parameters.  The format of this conf file is simple key
102       value pairs.  Comments and white space are ignored.
103
104         #-------------- file test.conf --------------
105
106         ### server information
107         max_servers   80
108
109         max_requests  1000
110
111         ### user and group to become
112         user        somebody
113         group       everybody
114
115         ### logging ?
116         log_file    /var/log/server.log
117         log_level   3
118         pid_file    /tmp/server.pid
119
120         ### access control
121         allow       .+\.(net|com)
122         allow       domain\.com
123         deny        a.+
124
125         ### background the process?
126         background  1
127
128         ### ports to bind
129         host        127.0.0.1
130         port        localhost:20204
131         port        20205
132
133         ### reverse lookups ?
134         # reverse_lookups on
135
136         #-------------- file test.conf --------------
137

PROCESS FLOW

139       Process flow follows Net::Server until the loop phase.  At this point
140       "max_servers" are forked and wait for connections.  When a child
141       accepts a connection, finishs processing a client, or exits, it relays
142       that information to the parent, which keeps track and makes sure there
143       are always "max_servers" running.
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HOOKS

146       The PreForkSimple server has the following hooks in addition to the
147       hooks provided by the Net::Server base class.  See Net::Server
148
149       "$self->run_n_children_hook()"
150           This hook occurs at the top of run_n_children which is called each
151           time the server goes to start more child processes.  This gives the
152           parent to do a little of its own accountting (as desired).  Idea
153           for this hook came from James FitzGibbon.
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155       "$self->child_init_hook()"
156           This hook takes place immeditately after the child process forks
157           from the parent and before the child begins accepting connections.
158           It is intended for any addiotional chrooting or other security
159           measures.  It is suggested that all perl modules be used by this
160           point, so that the most shared memory possible is used.
161
162       "$self->child_finish_hook()"
163           This hook takes place immediately before the child tells the parent
164           that it is exiting.  It is intended for saving out logged
165           information or other general cleanup.
166
167       "$self->run_dequeue()"
168           This hook only gets called in conjuction with the check_for_dequeue
169           setting.
170

BUGS

172       Tests don't seem to work on Win32.  Any ideas or patches would be
173       welcome.
174

TO DO

176       See Net::Server
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AUTHOR

179       Paul T. Seamons paul@seamons.com
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THANKS

182       See Net::Server
183