1Parallel::Runner(3pm) User Contributed Perl DocumentationParallel::Runner(3pm)
2
6 Parallel::Runner - An object to manage running things in parallel
7 processes.
8
10 There are several other modules to do this, you probably want one of
11 them. This module exists as a super specialised parallel task manager.
12 You create the object with a proces limit and callbacks for what to do
13 while waiting for a free process slot, as well as a callback for what a
14 process shoudl do just before exiting.
15 You must explicetly call $runner->finish() when you are done. If the
17 runner is destroyed before it's children are finished a warning will be
18 generated and your child processes will be killed, by force if
19 necessary.
20 If you specify a maximum of 1 then no forking will occur, and run()
22 will block until the coderef returns. You can force a fork by providing
23 a boolean true value as the second argument to run(), this will force
24 the runner to fork before running the coderef, however run() will still
25 block until it the child exits.
26
28 #!/usr/bin/perl
29 use strict;
30 use warnings;
31 use Parallel::Runner;
32 my $runner = Parallel::Runner->new(4);
34 $runner->run( sub { ... } );
35 $runner->run( sub { ... } );
36 $runner->run( sub { ... } );
37 $runner->run( sub { ... } );
38 # This will block until one of the previous 4 finishes
40 $runner->run( sub { ... } );
41 # Do not forget this.
43 $runner->finish;
44
46 $runner = $class->new( $max, $accessor => $value, ... );
47 Create a new instance of Parallel::Runner. $accessor can be
48 anything listed under the ACCESSORS section. $max should be the
49 maximum number of processes allowed, defaults to 1.
50
52 These are simple accessors, provididng an argument sets the accessor to
53 that argument, no argument it simply returns the current value.
54 $val = $runner->data_callback( \&callback )
56 If this is specified than IPC will be automatically enabled, and
57 the final return from each process will be passed into this handler
58 in the main process. Due to the way IPC works only
59 strings/numerical data is passed, if you need to pass a ref you
60 will need to serialize it yourself before returning it, followed by
61 deserializing it in your callback.
62 Example:
64 # Place to put the accumulated data
66 my @accum_data;
67 # Create the runner with a callback that pushes the data onto our array.
69 $runner = $CLASS->new( 2,
70 data_callback => sub {
71 my ($data) = @_;
72 push @accum_data => $data;
73 },
74 );
75 # 4 processes that return data
77 $runner->run( sub { return "foo" });
78 $runner->run( sub { return "bar" });
79 $runner->run( sub { return "baz" });
80 $runner->run( sub { return "bat" });
81 $runner->finish;
82 # Verify the data (order is not predictable)
84 is_deeply(
85 [ sort @accum_data ],
86 [ sort qw/foo bar baz bat/ ],
87 "Got all data returned by subprocesses"
88 );
89 $val = $runner->exit_callback( \&callback )
91 Codref to call just before a child exits (called within child)
92 $val = $runner->iteration_delay( $float );
94 How long to wait per iterate if nothing has changed.
95 $val = $runner->iteration_callback( $newval )
97 Coderef to call multiple times in a loop while run() is blocking
98 waiting for a process slot.
99 $val = $runner->reap_callback( $newval )
101 Codref to call whenever a pid is reaped using waitpid. The callback
102 sub will be passed 3 values The first is the exit status of the
103 child process. The second is the pid of the child process. The
104 third used to be the return of waitpid, but this is depricated as
105 Child is now used and throws an exception when waitpid is not what
106 it should be. The third is simply the pid of the child process
107 again. The final argument is the child process object itself.
108 $runner->reap_callback( sub {
110 my ( $status, $pid, $pid_again, $proc ) = @_;
111 # Status as returned from system, so 0 is good, 1+ is bad.
113 die "Child $pid did not exit 0"
114 if $status;
115 });
116 @children = $runner->children( @append )
118 Returns a list of Child::Link::Proc objects.
119 $val = $runner->pid()
121 pid of the parent process
122 $val = $runner->max( $newval )
124 Maximum number of children
125
127 run( $code )
128 run( $code, $force_fork )
129 Run the specified code in a child process. Blocks if no free slots
130 are available. Force fork can be used to force a fork when max is
131 1, however it will still block until the child exits.
132 finish()
134 finish( $timeout )
135 finish( $timeout, $timeoutcallback )
136 Wait for all children to finish, then clean up after them. If a
137 timeout is specified it will return after the timeout regardless of
138 wether or not children have all exited. If there is a timeout call
139 back then that code will be run upon timeout just before the method
140 returns.
141 NOTE: DO NOT LET YOUR RUNNER BE DESTROYED BEFORE FINISH COMPLETES
143 WITHOUT A TIMEOUT.
144 the runner will kill all children, possibly with force if your
146 runner is destroyed with children still running, or not waited on.
147 killall( $sig )
149 Send all children the specified kill signal.
150 DESTROY()
152 Automagically called when the object is destroyed. If called while
153 children are running it will forcefully clean up after you as
154 follows:
155 1) Sends an ugly warning.
157 2) Will first give all your children 1 second to complete.
159 Windows) Strawberry fails with processes, so on windows DESTROY
161 will wait as long as needed, possibly forever.
162 3) Sends kill signal 15 to all children then waits up to 4 seconds.
164 4) Sends kill signal 9 to any remaining children then waits up to
166 10 seconds
167 5) Gives up and returns
169
171 This module is part of the Fennec project. See Fennec for more details.
172 Fennec is a project to develop an extendable and powerful testing
173 framework. Together the tools that make up the Fennec framework
174 provide a potent testing environment.
175 The tools provided by Fennec are also useful on their own. Sometimes a
177 tool created for Fennec is useful outside the greator framework. Such
178 tools are turned into their own projects. This is one such project.
179 Fennec - The core framework
181 The primary Fennec project that ties them all together.
182
184 Chad Granum exodist7@gmail.com
185
187 Copyright (C) 2010 Chad Granum
188 Parallel-Runner is free software; Standard perl licence.
190 Parallel-Runner is distributed in the hope that it will be useful, but
192 WITHOUT ANY WARRANTY; without even the implied warranty of
193 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the license
194 for more details.
195perl v5.38.0 2023-07-21 Parallel::Runner(3pm)