1Parallel::Prefork(3) User Contributed Perl Documentation Parallel::Prefork(3)
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6 Parallel::Prefork - A simple prefork server framework
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9 use Parallel::Prefork;
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11 my $pm = Parallel::Prefork->new({
12 max_workers => 10,
13 trap_signals => {
14 TERM => 'TERM',
15 HUP => 'TERM',
16 USR1 => undef,
17 }
18 });
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20 while ($pm->signal_received ne 'TERM') {
21 load_config();
22 $pm->start(sub {
23 ... do some work within the child process ...
24 });
25 }
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27 $pm->wait_all_children();
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30 "Parallel::Prefork" is much like "Parallel::ForkManager", but supports
31 graceful shutdown and run-time reconfiguration.
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34 new
35 instantiation. Takes a hashref as an argument. Recognized attributes
36 are as follows.
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38 max_workers
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40 number of worker processes (default: 10)
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42 spawn_interval
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44 interval in seconds between spawning child processes unless a child
45 process exits abnormally (default: 0)
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47 err_respawn_interval
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49 number of seconds to deter spawning of child processes after a worker
50 exits abnormally (default: 1)
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52 trap_signals
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54 hashref of signals to be trapped. Manager process will trap the
55 signals listed in the keys of the hash, and send the signal specified
56 in the associated value (if any) to all worker processes. If the
57 associated value is a scalar then it is treated as the name of the
58 signal to be sent immediately to all the worker processes. If the
59 value is an arrayref the first value is treated the name of the signal
60 and the second value is treated as the interval (in seconds) between
61 sending the signal to each worker process.
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63 on_child_reap
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65 coderef that is called when a child is reaped. Receives the instance to
66 the current Parallel::Prefork, the child's pid, and its exit status.
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68 before_fork
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70 after_fork
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72 coderefs that are called in the manager process before and after fork,
73 if being set
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75 start
76 The main routine. There are two ways to use the function.
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78 If given a subref as an argument, forks child processes and executes
79 that subref within the child processes. The processes will exit with 0
80 status when the subref returns.
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82 The other way is to not give any arguments to the function. The
83 function returns undef in child processes. Caller should execute the
84 application logic and then call "finish" to terminate the process.
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86 The "start" function returns true within manager process upon receiving
87 a signal specified in the "trap_signals" hashref.
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89 finish
90 Child processes (when executed by a zero-argument call to "start")
91 should call this function for termination. Takes exit code as an
92 optional argument. Only usable from child processes.
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94 signal_all_children
95 Sends signal to all worker processes. Only usable from manager
96 process.
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98 wait_all_children()
99 wait_all_children($timeout)
100 Waits until all worker processes exit or timeout (given as an optional
101 argument in seconds) exceeds. The method returns the number of the
102 worker processes still running.
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105 Kazuho Oku
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108 This program is free software; you can redistribute it and/or modify it
109 under the same terms as Perl itself.
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111 See http://www.perl.com/perl/misc/Artistic.html
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115perl v5.28.1 2016-02-10 Parallel::Prefork(3)