1Net::Server::PreFork(3)User Contributed Perl DocumentatioNnet::Server::PreFork(3)
2
6 Net::Server::PreFork - Net::Server personality
7
9 use base qw(Net::Server::PreFork);
10 sub process_request {
12 #...code...
13 }
14 __PACKAGE__->run();
16
18 Please read the pod on Net::Server and Net::Server::PreForkSimple
19 first. This module is a personality, or extension, or sub class, of
20 the Net::Server::PreForkSimple class which is a sub class of
21 Net::Server. See Net::Server::PreForkSimple.
22 This personality binds to one or more ports and then forks
24 "min_servers" child process. The server will make sure that at any
25 given time there are "min_spare_servers" available to receive a client
26 request, up to "max_servers". Each of these children will process up
27 to "max_requests" client connections. This type is good for a heavily
28 hit site, and should scale well for most applications. (Multi port
29 accept is accomplished using flock to serialize the children).
30 At this time, it does not appear that this module will pass tests on
32 Win32 systems. Any ideas or patches for making the tests pass would be
33 welcome.
34
36 Please see the sample listed in Net::Server.
37
39 In addition to the command line arguments of the Net::Server base class
40 and the Net::Server::PreForkSimple parent class, Net::Server::PreFork
41 contains several other configurable parameters. You really should also
42 see Net::Server::PreForkSimple.
43 Key Value Default
45 min_servers \d+ 5
46 min_spare_servers \d+ 2
47 max_spare_servers \d+ 10
48 max_servers \d+ 50
49 max_requests \d+ 1000
50 serialize (flock|semaphore
52 |pipe|none) undef
53 # serialize defaults to flock on multi_port or on Solaris
54 lock_file "filename" File::Temp->new
55 check_for_dead \d+ 30
57 check_for_waiting \d+ 10
58 max_dequeue \d+ undef
60 check_for_dequeue \d+ undef
61 child_communication 1 undef
63 min_servers
65 The minimum number of servers to keep running.
66 min_spare_servers
68 The minimum number of servers to have waiting for requests.
69 Minimum and maximum numbers should not be set to close to each
70 other or the server will fork and kill children too often.
71 max_spare_servers
73 The maximum number of servers to have waiting for requests. See
74 min_spare_servers.
75 max_servers
77 The maximum number of child servers to start. This does not apply
78 to dequeue processes.
79 check_for_waiting
81 Seconds to wait before checking to see if we can kill off some
82 waiting servers.
83 check_for_spawn
85 Seconds between checking to see if we need to spawn more children
86 min_child_ttl
88 Minimum number of seconds between starting children and killing a
89 child process
90 child_communication
92 Enable child communication to parent via unix sockets. If set to
93 true, will let children write to the socket contained in
94 $self->{'server'}->{'parent_sock'}. The parent will be notified
95 through child_is_talking_hook where the first argument is the
96 socket to the child. The child's socket is stored in
97 $self->{'server'}->{'children'}->{$child_pid}->{'sock'}.
98 serialize
100 See the documentation under Net::Server::PreForkSimple.
101
103 "Net::Server::PreFork" allows for the use of a configuration file to
104 read in server parameters. The format of this conf file is simple key
105 value pairs. Comments and white space are ignored.
106 #-------------- file test.conf --------------
108 ### server information
110 min_servers 20
111 max_servers 80
112 min_spare_servers 10
113 min_spare_servers 15
114 max_requests 1000
116 ### user and group to become
118 user somebody
119 group everybody
120 ### logging ?
122 log_file /var/log/server.log
123 log_level 3
124 pid_file /tmp/server.pid
125 ### access control
127 allow .+\.(net|com)
128 allow domain\.com
129 deny a.+
130 ### background the process?
132 background 1
133 ### ports to bind
135 host 127.0.0.1
136 port localhost:20204
137 port 20205
138 ### reverse lookups ?
140 # reverse_lookups on
141 ### enable child communication ?
143 # child_communication
144 #-------------- file test.conf --------------
146
148 Process flow follows Net::Server until the loop phase. At this point
149 "min_servers" are forked and wait for connections. When a child
150 accepts a connection, finishs processing a client, or exits, it relays
151 that information to the parent, which keeps track and makes sure there
152 are enough children to fulfill "min_servers", "min_spare_servers",
153 "max_spare_servers", and "max_servers".
154
156 The PreFork server has the following hooks in addition to the hooks
157 provided by PreForkSimple. See Net::Server::PreForkSimple.
158 "$self->run_n_children_hook()"
160 This hook occurs at the top of run_n_children which is called each
161 time the server goes to start more child processes. This gives the
162 parent to do a little of its own accountting (as desired). Idea
163 for this hook came from James FitzGibbon.
164 "$self->parent_read_hook()"
166 This hook occurs any time that the parent reads information from
167 the child. The line from the child is sent as an argument.
168 "$self->child_is_talking_hook()"
170 This hook occurs if child_communication is true and the child has
171 written to $self->{'server'}->{'parent_sock'}. The first argument
172 will be the open socket to the child.
173 "$self->idle_loop_hook()"
175 This hook is called in every pass through the main process wait
176 loop, every "check_for_waiting" seconds. The first argument is a
177 reference to an array of file descriptors that can be read at the
178 moment.
179 "$self->cleanup_dead_child_hook( $child )"
181 This hook is called when a dead child is detected. A child is
182 considered dead when the pid does no longer exist. This hook could
183 be used to cleanup possible temporary files or locks left over by a
184 dead child. =back
185
187 Since version 2.000, the PreFork server has accepted the TTIN and TTOU
188 signals. When a TTIN is received, the min and max_servers are
189 increased by 1. If a TTOU signal is received the min max_servers are
190 decreased by 1. This allows for adjusting the number of handling
191 processes without having to restart the server.
192
194 Tests don't seem to work on Win32. Any ideas or patches would be
195 welcome.
196
198 See Net::Server
199
201 Paul T. Seamons paul@seamons.com
202
204 See Net::Server
205
207 Please see also Net::Server::Fork, Net::Server::INET,
208 Net::Server::PreForkSimple, Net::Server::MultiType, Net::Server::Single
209 Net::Server::SIG Net::Server::Daemonize Net::Server::Proto
210
212 Hey! The above document had some coding errors, which are explained
213 below:
214 Around line 683:
216 You forgot a '=back' before '=head1'
217perl v5.26.3 2017-08-10 Net::Server::PreFork(3)