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Comparing AnyEvent-Fork/Fork.pm (file contents):
Revision 1.49 by root, Fri Apr 19 12:56:53 2013 UTC vs.
Revision 1.59 by root, Fri Aug 30 12:06:48 2013 UTC

38 38
39If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC> 39If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC>
40companion module, which adds simple RPC/job queueing to a process created 40companion module, which adds simple RPC/job queueing to a process created
41by this module. 41by this module.
42 42
43And if you need some automatic process pool management on top of
44L<AnyEvent::Fork::RPC>, you can look at the L<AnyEvent::Fork::Pool>
45companion module.
46
43Or you can implement it yourself in whatever way you like, use some 47Or you can implement it yourself in whatever way you like: use some
44message-passing module such as L<AnyEvent::MP>, some pipe such as 48message-passing module such as L<AnyEvent::MP>, some pipe such as
45L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send 49L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send
46e.g. JSON or Storable messages, and so on. 50e.g. JSON or Storable messages, and so on.
47 51
48=head2 COMPARISON TO OTHER MODULES 52=head2 COMPARISON TO OTHER MODULES
250 ->send_arg ("/bin/echo", "hi") 254 ->send_arg ("/bin/echo", "hi")
251 ->run ("run", my $cv = AE::cv); 255 ->run ("run", my $cv = AE::cv);
252 256
253 my $stderr = $cv->recv; 257 my $stderr = $cv->recv;
254 258
259=head2 For stingy users: put the worker code into a C<DATA> section.
260
261When you want to be stingy with files, you cna put your code into the
262C<DATA> section of your module (or program):
263
264 use AnyEvent::Fork;
265
266 AnyEvent::Fork
267 ->new
268 ->eval (do { local $/; <DATA> })
269 ->run ("doit", sub { ... });
270
271 __DATA__
272
273 sub doit {
274 ... do something!
275 }
276
277=head2 For stingy standalone programs: do not rely on external files at
278all.
279
280For single-file scripts it can be inconvenient to rely on external
281files - even when using < C<DATA> section, you still need to C<exec>
282an external perl interpreter, which might not be available when using
283L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example.
284
285Two modules help here - L<AnyEvent::Fork::Early> forks a template process
286for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template>
287forks the main program as a template process.
288
289Here is how your main program should look like:
290
291 #! perl
292
293 # optional, as the very first thing.
294 # in case modules want to create their own processes.
295 use AnyEvent::Fork::Early;
296
297 # next, load all modules you need in your template process
298 use Example::My::Module
299 use Example::Whatever;
300
301 # next, put your run function definition and anything else you
302 # need, but do not use code outside of BEGIN blocks.
303 sub worker_run {
304 my ($fh, @args) = @_;
305 ...
306 }
307
308 # now preserve everything so far as AnyEvent::Fork object
309 # in §TEMPLATE.
310 use AnyEvent::Fork::Template;
311
312 # do not put code outside of BEGIN blocks until here
313
314 # now use the $TEMPLATE process in any way you like
315
316 # for example: create 10 worker processes
317 my @worker;
318 my $cv = AE::cv;
319 for (1..10) {
320 $cv->begin;
321 $TEMPLATE->fork->send_arg ($_)->run ("worker_run", sub {
322 push @worker, shift;
323 $cv->end;
324 });
325 }
326 $cv->recv;
327
255=head1 CONCEPTS 328=head1 CONCEPTS
256 329
257This module can create new processes either by executing a new perl 330This module can create new processes either by executing a new perl
258process, or by forking from an existing "template" process. 331process, or by forking from an existing "template" process.
259 332
377use AnyEvent; 450use AnyEvent;
378use AnyEvent::Util (); 451use AnyEvent::Util ();
379 452
380use IO::FDPass; 453use IO::FDPass;
381 454
382our $VERSION = 0.7; 455our $VERSION = 1.1;
383 456
384# the early fork template process 457# the early fork template process
385our $EARLY; 458our $EARLY;
386 459
387# the empty template process 460# the empty template process
435 # send string 508 # send string
436 my $len = syswrite $self->[FH], $self->[QUEUE][0]; 509 my $len = syswrite $self->[FH], $self->[QUEUE][0];
437 510
438 unless ($len) { 511 unless ($len) {
439 return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; 512 return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK;
440 undef $self->[3]; 513 undef $self->[WW];
441 die "AnyEvent::Fork: command write failure: $!"; 514 die "AnyEvent::Fork: command write failure: $!";
442 } 515 }
443 516
444 substr $self->[QUEUE][0], 0, $len, ""; 517 substr $self->[QUEUE][0], 0, $len, "";
445 shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; 518 shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0];
532 605
533You should use C<new> whenever possible, except when having a template 606You should use C<new> whenever possible, except when having a template
534process around is unacceptable. 607process around is unacceptable.
535 608
536The path to the perl interpreter is divined using various methods - first 609The path to the perl interpreter is divined using various methods - first
537C<$^X> is investigated to see if the path ends with something that sounds 610C<$^X> is investigated to see if the path ends with something that looks
538as if it were the perl interpreter. Failing this, the module falls back to 611as if it were the perl interpreter. Failing this, the module falls back to
539using C<$Config::Config{perlpath}>. 612using C<$Config::Config{perlpath}>.
540 613
614The path to perl can also be overriden by setting the global variable
615C<$AnyEvent::Fork::PERL> - it's value will be used for all subsequent
616invocations.
617
541=cut 618=cut
619
620our $PERL;
542 621
543sub new_exec { 622sub new_exec {
544 my ($self) = @_; 623 my ($self) = @_;
545 624
546 return $EARLY->fork 625 return $EARLY->fork
547 if $EARLY; 626 if $EARLY;
548 627
628 unless (defined $PERL) {
549 # first find path of perl 629 # first find path of perl
550 my $perl = $; 630 my $perl = $;
551 631
552 # first we try $^X, but the path must be absolute (always on win32), and end in sth. 632 # first we try $^X, but the path must be absolute (always on win32), and end in sth.
553 # that looks like perl. this obviously only works for posix and win32 633 # that looks like perl. this obviously only works for posix and win32
554 unless ( 634 unless (
555 ($^O eq "MSWin32" || $perl =~ m%^/%) 635 ($^O eq "MSWin32" || $perl =~ m%^/%)
556 && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i 636 && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i
557 ) { 637 ) {
558 # if it doesn't look perlish enough, try Config 638 # if it doesn't look perlish enough, try Config
559 require Config; 639 require Config;
560 $perl = $Config::Config{perlpath}; 640 $perl = $Config::Config{perlpath};
561 $perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/; 641 $perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/;
642 }
643
644 $PERL = $perl;
562 } 645 }
563 646
564 require Proc::FastSpawn; 647 require Proc::FastSpawn;
565 648
566 my ($fh, $slave) = AnyEvent::Util::portable_socketpair; 649 my ($fh, $slave) = AnyEvent::Util::portable_socketpair;
574 #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; 657 #local $ENV{PERL5LIB} = join ":", grep !ref, @INC;
575 my %env = %ENV; 658 my %env = %ENV;
576 $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; 659 $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC;
577 660
578 my $pid = Proc::FastSpawn::spawn ( 661 my $pid = Proc::FastSpawn::spawn (
579 $perl, 662 $PERL,
580 ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], 663 ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$],
581 [map "$_=$env{$_}", keys %env], 664 [map "$_=$env{$_}", keys %env],
582 ) or die "unable to spawn AnyEvent::Fork server: $!"; 665 ) or die "unable to spawn AnyEvent::Fork server: $!";
583 666
584 $self->_new ($fh, $pid) 667 $self->_new ($fh, $pid)
585} 668}
586 669
587=item $pid = $proc->pid 670=item $pid = $proc->pid
588 671
589Returns the process id of the process I<iff it is a direct child of the 672Returns the process id of the process I<iff it is a direct child of the
590process running AnyEvent::Fork>, and C<undef> otherwise. 673process running AnyEvent::Fork>, and C<undef> otherwise. As a general
674rule (that you cannot rely upon), processes created via C<new_exec>,
675L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template> are direct
676children, while all other processes are not.
591 677
592Normally, only processes created via C<< AnyEvent::Fork->new_exec >> and 678Or in other words, you do not normally have to take care of zombies for
593L<AnyEvent::Fork::Template> are direct children, and you are responsible 679processes created via C<new>, but when in doubt, or zombies are a problem,
594to clean up their zombies when they die. 680you need to check whether a process is a diretc child by calling this
595 681method, and possibly creating a child watcher or reap it manually.
596All other processes are not direct children, and will be cleaned up by
597AnyEvent::Fork itself.
598 682
599=cut 683=cut
600 684
601sub pid { 685sub pid {
602 $_[0][PID] 686 $_[0][PID]
733 817
734Even if not used otherwise, the socket can be a good indicator for the 818Even if not used otherwise, the socket can be a good indicator for the
735existence of the process - if the other process exits, you get a readable 819existence of the process - if the other process exits, you get a readable
736event on it, because exiting the process closes the socket (if it didn't 820event on it, because exiting the process closes the socket (if it didn't
737create any children using fork). 821create any children using fork).
822
823=over 4
824
825=item Compatibility to L<AnyEvent::Fork::Remote>
826
827If you want to write code that works with both this module and
828L<AnyEvent::Fork::Remote>, you need to write your code so that it assumes
829there are two file handles for communications, which might not be unix
830domain sockets. The C<run> function should start like this:
831
832 sub run {
833 my ($rfh, @args) = @_; # @args is your normal arguments
834 my $wfh = fileno $rfh ? $rfh : *STDOUT;
835
836 # now use $rfh for reading and $wfh for writing
837 }
838
839This checks whether the passed file handle is, in fact, the process
840C<STDIN> handle. If it is, then the function was invoked visa
841L<AnyEvent::Fork::Remote>, so STDIN should be used for reading and
842C<STDOUT> should be used for writing.
843
844In all other cases, the function was called via this module, and there is
845only one file handle that should be sued for reading and writing.
846
847=back
738 848
739Example: create a template for a process pool, pass a few strings, some 849Example: create a template for a process pool, pass a few strings, some
740file handles, then fork, pass one more string, and run some code. 850file handles, then fork, pass one more string, and run some code.
741 851
742 my $pool = AnyEvent::Fork 852 my $pool = AnyEvent::Fork
774 884
775 $self->[CB] = $cb; 885 $self->[CB] = $cb;
776 $self->_cmd (r => $func); 886 $self->_cmd (r => $func);
777} 887}
778 888
779=item $proc->to_fh ($cb->($fh)) 889=back
890
891=head2 EXPERIMENTAL METHODS
892
893These methods might go away completely or change behaviour, at any time.
894
895=over 4
896
897=item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED
780 898
781Flushes all commands out to the process and then calls the callback with 899Flushes all commands out to the process and then calls the callback with
782the communications socket. 900the communications socket.
783 901
784The process object becomes unusable on return from this function - any 902The process object becomes unusable on return from this function - any
785further method calls result in undefined behaviour. 903further method calls result in undefined behaviour.
786 904
787The point of this method is to give you a file handle thta you cna pass 905The point of this method is to give you a file handle that you can pass
788to another process. In that other process, you can call C<new_from_fh 906to another process. In that other process, you can call C<new_from_fh
789AnyEvent::Fork::RPC> to create a new C<AnyEvent::Fork> object from it, 907AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it,
790thereby effectively passing a fork object to another process. 908thereby effectively passing a fork object to another process.
791 909
792=cut 910=cut
793 911
794sub to_fh { 912sub to_fh {
800 $self->[CB]->($self->[FH]); 918 $self->[CB]->($self->[FH]);
801 @$self = (); 919 @$self = ();
802 } 920 }
803} 921}
804 922
805=item new_from_fh AnyEvent::Fork $fh 923=item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED
806 924
807Takes a file handle originally rceeived by the C<to_fh> method and creates 925Takes a file handle originally rceeived by the C<to_fh> method and creates
808a new C<AnyEvent:Fork> object. The child process itself will not change in 926a new C<AnyEvent:Fork> object. The child process itself will not change in
809any way, i.e. it will keep all the modifications done to it before calling 927any way, i.e. it will keep all the modifications done to it before calling
810C<to_fh>. 928C<to_fh>.
970(part of this distribution). 1088(part of this distribution).
971 1089
972L<AnyEvent::Fork::Template>, to create a process by forking the main 1090L<AnyEvent::Fork::Template>, to create a process by forking the main
973program at a convenient time (part of this distribution). 1091program at a convenient time (part of this distribution).
974 1092
1093L<AnyEvent::Fork::Remote>, for another way to create processes that is
1094mostly compatible to this module and modules building on top of it, but
1095works better with remote processes.
1096
975L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). 1097L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN).
1098
1099L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN).
976 1100
977=head1 AUTHOR AND CONTACT INFORMATION 1101=head1 AUTHOR AND CONTACT INFORMATION
978 1102
979 Marc Lehmann <schmorp@schmorp.de> 1103 Marc Lehmann <schmorp@schmorp.de>
980 http://software.schmorp.de/pkg/AnyEvent-Fork 1104 http://software.schmorp.de/pkg/AnyEvent-Fork

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