NAME MooseX::Workers - Simple sub-process management for asynchronous tasks SYNOPSIS EXAMPLE #1: package Manager; # This example prints output from the children normally on both STDOUT and STDERR use Moose; with qw(MooseX::Workers); sub run { $_[0]->spawn( sub { sleep 3; print "Hello World\n" } ); warn "Running now ... "; POE::Kernel->run(); } # Implement our Interface sub worker_stdout { shift; warn join ' ', @_; } sub worker_stderr { shift; warn join ' ', @_; } sub worker_manager_start { warn 'started worker manager' } sub worker_manager_stop { warn 'stopped worker manager' } sub max_workers_reached { warn 'maximum worker count reached' } sub worker_error { shift; warn join ' ', @_; } sub worker_finished { warn 'a worker has finished' } sub worker_started { shift; warn join ' ', @_; } sub sig_child { shift; warn join ' ', @_; } sub sig_TERM { shift; warn 'Handled TERM' } no Moose; Manager->new->run(); EXAMPLE #2: package Manager; # This example prints output from the children normally on # STDERR but uses STDOUT to returns a hashref from the child to # the parent use Moose; with qw(MooseX::Workers); use POE qw(Filter::Reference Filter::Line); sub run { $_[0]->spawn( sub { sleep 3; # Return a hashref (arrayref, whatever) to the parent using P::F::Reference print @{POE::Filter::Reference->new->put([ {msg => "Hello World"} ])}; # Note the [] around the return val # Print normally using P::F::Line (shown for # completeness; in practice, just don't bother # defining the _filter method # print STDERR "Hey look, an error message"; } ); POE::Kernel->run(); } # Implement our Interface # These two are both optional; if defined (as here), they # should return a subclass of POE::Filter. sub stdout_filter { POE::Filter::Reference->new } sub stderr_filter { POE::Filter::Line->new } sub worker_stdout { my ( $self, $result ) = @_; # $result will be a hashref: {msg => "Hello World"} print $result->{msg}; # Note that you can do more than just print the message -- # e.g. this is the way to return data from the children for # accumulation in the parent. } sub worker_stderr { my ( $self, $stderr_msg ) = @_; # $stderr_msg will be a string: "Hey look, an error message"; warn $stderr_msg; } # From here down, this is identical to the previous example. sub worker_manager_start { warn 'started worker manager' } sub worker_manager_stop { warn 'stopped worker manager' } sub max_workers_reached { warn 'maximum worker count reached' } sub worker_error { shift; warn join ' ', @_; } sub worker_finished { warn 'a worker has finished' } sub worker_started { shift; warn join ' ', @_; } sub sig_child { shift; warn join ' ', @_; } sub sig_TERM { shift; warn 'Handled TERM' } no Moose; Manager->new->run(); DESCRIPTION MooseX::Workers is a Role that provides easy delegation of long-running tasks into a managed child process. Process management is taken care of via POE and its POE::Wheel::Run module. METHODS spawn ($command) fork ($command) run_command ($command) These three methods are the whole point of this module. They pass $command through to the MooseX::Worker::Engine which will take care of running $command for you. spawn() and fork() both invoke POE::Kernel call(), which is synchronous. run_command() invokes POE::Kernel yield(), which is asynchronous. If max_workers() has been reached, run_command() warns and does nothing. It is up to you to re-submit $command. See enqueue() if you want us to run $command as soon as another worker is free. enqueue($command) Just like run_command(), only that if max_workers() has been set and that number of workers has been reached, then we add $command to a FIFO command queue. As soon as any running worker exits, the first $command in queue (if any) will be run. check_worker_threshold This will check to see how many workers you have compared to the max_workers limit. It returns true if the $num_workers is >= $max_workers; max_workers($count) An accessor for the maximum number of workers. This is delegated to the MooseX::Workers::Engine object. has_workers Check to see if we have *any* workers currently. This is delegated to the MooseX::Workers::Engine object. num_workers Return the current number of workers. This is delegated to the MooseX::Workers::Engine object. meta The Metaclass for MooseX::Workers::Engine see Moose's documentation. INTERFACE MooseX::Worker::Engine supports the following callbacks: worker_manager_start Called when the managing session is started worker_manager_stop Called when the managing session stops max_workers_reached Called when we reach the maximum number of workers stdout_filter OPTIONAL. If defined, this should return an object that isa POE::Filter. If it doesn't, the results are undefined. Anything that a child proc sends on STDOUT will be passed through the relevant filter. stderr_filter OPTIONAL. If defined, this should return an object that isa POE::Filter. If it doesn't, the results are undefined. Anything that a child proc sends on STDERR will be passed through the relevant filter. worker_stdout Called when a child prints to STDOUT. If stdout_filter was defined, the output will be filtered appropriately, as described above. This is useful to allow child processes to return data to the parent (generally via POE::Filter::Reference). worker_stderr Called when a child prints to STDERR. Filtered through the result of stderr_filter if that method is defined. worker_error Called when there is an error condition detected with the child. worker_finished Called when a worker completes $command. If the command was a MooseX::Workers::Job, it will get the removed job instance as the first parameter. worker_done *DEPRECATED* This is called before the worker is removed, so "num_workers" and "has_workers" does not reflect that a worker has just finished. Use "worker_finished" instead. Gets the MooseX::Workers::Job instance, if the $command was a job, and the POE::Wheel::Run id otherwise. worker_started Called when a worker starts $command sig_child Called when the mangaging session recieves a SIG CHLD event sig_* Called when the underlying POE Kernel receives a signal; this is not limited to OS signals (ie. what you'd usually handle in Perl's %SIG) so will also accept arbitrary POE signals (sent via POE::Kernel->signal), but does exclude SIGCHLD/SIGCHILD, which is instead handled by sig_child above. These interface methods are automatically inserted when MooseX::Worker::Engine detects that your manager class contains any methods beginning with sig_. Signals are case-sensitive, so if you wish to handle a TERM signal, you must define a sig_TERM() method. Note also that this action is performed upon MooseX::Worker::Engine startup, so any run-time modification of your class which 'does' MooseX::Workers is not likely to be detected. See the sig_TERM handler in the SYNOPSIS for an example. See MooseX::Workers::Engine for more details. Also see MooseX::Workers::Job if you'd like to give your tasks names, or set timeouts on them. WIN32 NOTES You don't need to binmode the STDIN/STDOUT/STDERR streams in your coderefs, this is done for you. If you need utf8, it is safe to re-binmode them to :encoding(UTF-8). Coderef workers that time out are killed with a SIGINT rather than a SIGTERM, because TERM does not behave compatibly (thanks Rocco!) This is done with a: local $SIG{INT} = sub { exit 0 }; that wraps the coderef. You cannot catch a TERM sent to the parent process (see "kill" in perlport, use INT instead. External programs are run with Win32::Job by POE::Wheel::Run. They are prepended with cmd /c so that builtin cmd commands also work. Use a MooseX::Workers::Job with a string program and arrayref args for this. If you are using POE::Filter::Line with an external program (which is the default if you don't set the filter) the CRs from line ends will be removed automatically. BUGS AND LIMITATIONS Please report any bugs or feature requests to bug-moosex-workers@rt.cpan.org, or through the web interface at http://rt.cpan.org. Version control: https://github.com/jhannah/moosex-workers AUTHORS Chris Prather Tom Lanyon Jay Hannah Justin Hunter David K. Storrs Rafael Kitover LICENCE AND COPYRIGHT Copyright (c) 2007-2013, Chris Prather . Some rights reserved. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic. 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