NAME
POE::Component::WheelRun::Pool - POE::Wheel::Run worker pool
VERSION
version 0.001
SYNOPSIS
Provides a pool wrapper around POE::Wheel::Run to allow for large worker pools that are automatically replenished. POE::Component::WheelRun::Pool uses STDIN, STDOUT, and STDERR for communication between the parent session and the worker children.
my $worker_pool_id = POE::Component::WheelRun::Pool->spawn(
Alias => 'pool', # Default
Program => \&run_analysis, # Required
PoolSize => 4, # Default
MaxTasksPerChild => 1000, # Default '0' = unlimited
MaxTimePerChild => 3600, # Default '0' = unlimited
Splay => 0.1, # Default
# Any Options from POE::Wheel::Run
User => 'bob',
Group => 'nobody',
Priority => 5,
);
my $main = POE::Session->create(inline_states => {
new_event => sub { $poe_kernel->post( pool => dispatch => @_[ARG0] ) },
});
This will create a pool of 4 workers with the run_analyze function as the entry point to the pool::dispatch event. Child processes should monitor STDIN for availability as the first thing attempted by the parent is an EOF on the STDIN of the child to let it know it should go away. Failing this, a kill() is called which is SIGINT by default.
FUNCTIONS
spawn()
Creates the worker pool and sets it ready for incoming tasks. POE::Component::WheelRun::Pool will pass sensible options from POE::Wheel::Run to the child process. See:
perldoc POE::Wheel::Run
For more information on options not covered here.
Alias
Default is 'pool', use a unique name to make dispatching events to worker pools easier to understand.
Program
Required! Can be either a CODE reference or a path to an executable to launch. The script needs to be able to accept data on STDIN and communicate back to the parent session using STDOUT or STDERR. This means the program can be in any language.
PoolSize
Default is 4. This is the number of children to spawn and maintain.
MaxTasksPerChild
Default 0, anything <= 0 means unlimited. This is the maximum number of tasks that can be handed to any one worker before it needs to respawn.
MaxTimePerChild
Default 0, anything <= 0 means unlimited. This is the maximum number of seconds any worker can live before being killed and respawned. This check occurs only inside of the dispatch event trigger and only for that "next" worker. This means it is possible for processes to live longer that MaxTimePerChild, but their next invocation will be their last.
Splay
Default is 0.1 and is unimportant without MaxTimePerChild or MaxTasksPerChild. This applies a random splay to the time or tasks checker. Best thought of as a percentage range for max tasks or time. e. g.
ChildMaxUpperBound = MaxTasksPerChild + (Splay * MaxTasksPerChild) ChildMaxLowerBound = MaxTasksPerChild - (Splay * MaxTasksPerChild)When a child is spawned the max tasks/time is calculated inside that range using two calls to rand(), one for the Splay and the second for positive/negative.
The idea behind this is to offset process creation in the parent process as that can be expensive. If you would like to disable this feature, set the Splay to 0.
StatsInterval
Default is 60. Seconds to run the stats handler.
StatsHandler
Default 'undef'. If passed a CODE reference, that refernce is run every StatInterval seconds. The handler is passed a hash reference with the events tracked and the values representing the number of times each event ocurred.
StdoutHandler
Default 'undef'. CODE reference with what to do when there's content on STDOUT of the worker process. Based on StdioFilter or StdoutFilter this reference may be passed the content as a stream, line of text, or even a Perl object.
StderrHandler
Default 'undef'. CODE reference with what to do when there's content on STDERR of the worker process. Based on StderrFilter this reference may be passed the content as a stream, line of text, or even a Perl object.
AUTHOR
Brad Lhotsky brad@divisionbyzero.net
COPYRIGHT AND LICENSE
This software is Copyright (c) 2016 by Brad Lhotsky.
This is free software, licensed under:
The (three-clause) BSD License
CONTRIBUTORS
- Brad Lhotsky blhotsky@craigslist.org
- Brad Lhotsky brad.lhotsky@booking.com
SUPPORT
Websites
The following websites have more information about this module, and may be of help to you. As always, in addition to those websites please use your favorite search engine to discover more resources.
MetaCPAN
A modern, open-source CPAN search engine, useful to view POD in HTML format.
RT: CPAN's Bug Tracker
The RT ( Request Tracker ) website is the default bug/issue tracking system for CPAN.
https://rt.cpan.org/Public/Dist/Display.html?Name=POE-Component-WheelRun-Pool
Source Code
This module's source code is available by visiting: https://github.com/reyjrar/POE-Component-WheelRun-Pool