… | |
… | |
38 | |
38 | |
39 | If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC> |
39 | If you need some form of RPC, you could use the L<AnyEvent::Fork::RPC> |
40 | companion module, which adds simple RPC/job queueing to a process created |
40 | companion module, which adds simple RPC/job queueing to a process created |
41 | by this module. |
41 | by this module. |
42 | |
42 | |
|
|
43 | And if you need some automatic process pool management on top of |
|
|
44 | L<AnyEvent::Fork::RPC>, you can look at the L<AnyEvent::Fork::Pool> |
|
|
45 | companion module. |
|
|
46 | |
43 | Or you can implement it yourself in whatever way you like, use some |
47 | Or you can implement it yourself in whatever way you like: use some |
44 | message-passing module such as L<AnyEvent::MP>, some pipe such as |
48 | message-passing module such as L<AnyEvent::MP>, some pipe such as |
45 | L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send |
49 | L<AnyEvent::ZeroMQ>, use L<AnyEvent::Handle> on both sides to send |
46 | e.g. JSON or Storable messages, and so on. |
50 | e.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 | |
|
|
261 | When you want to be stingy with files, you cna put your code into the |
|
|
262 | C<DATA> section of your module (or program): |
|
|
263 | |
|
|
264 | use AnyEvent::Fork; |
|
|
265 | |
|
|
266 | AnyEvent::Fork |
|
|
267 | ->new |
|
|
268 | ->eval (do { local $/; <DATA> }) |
|
|
269 | ->run ("doit", sub { ... }); |
|
|
270 | |
|
|
271 | __DATA__ |
|
|
272 | |
|
|
273 | sub doit { |
|
|
274 | ... do something! |
|
|
275 | } |
|
|
276 | |
|
|
277 | =head2 For stingy standalone programs: do not rely on external files at |
|
|
278 | all. |
|
|
279 | |
|
|
280 | For single-file scripts it can be inconvenient to rely on external |
|
|
281 | files - even when using < C<DATA> section, you still need to C<exec> |
|
|
282 | an external perl interpreter, which might not be available when using |
|
|
283 | L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example. |
|
|
284 | |
|
|
285 | Two modules help here - L<AnyEvent::Fork::Early> forks a template process |
|
|
286 | for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template> |
|
|
287 | forks the main program as a template process. |
|
|
288 | |
|
|
289 | Here is how your main program should look like: |
|
|
290 | |
|
|
291 | #! perl |
|
|
292 | |
|
|
293 | # optional, as the very first thing. |
|
|
294 | # in case modules want to create their own processes. |
|
|
295 | use AnyEvent::Fork::Early; |
|
|
296 | |
|
|
297 | # next, load all modules you need in your template process |
|
|
298 | use Example::My::Module |
|
|
299 | use Example::Whatever; |
|
|
300 | |
|
|
301 | # next, put your run function definition and anything else you |
|
|
302 | # need, but do not use code outside of BEGIN blocks. |
|
|
303 | sub worker_run { |
|
|
304 | my ($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 | |
257 | This module can create new processes either by executing a new perl |
330 | This module can create new processes either by executing a new perl |
258 | process, or by forking from an existing "template" process. |
331 | process, or by forking from an existing "template" process. |
|
|
332 | |
|
|
333 | All these processes are called "child processes" (whether they are direct |
|
|
334 | children or not), while the process that manages them is called the |
|
|
335 | "parent process". |
259 | |
336 | |
260 | Each such process comes with its own file handle that can be used to |
337 | Each such process comes with its own file handle that can be used to |
261 | communicate with it (it's actually a socket - one end in the new process, |
338 | communicate with it (it's actually a socket - one end in the new process, |
262 | one end in the main process), and among the things you can do in it are |
339 | one end in the main process), and among the things you can do in it are |
263 | load modules, fork new processes, send file handles to it, and execute |
340 | load modules, fork new processes, send file handles to it, and execute |
… | |
… | |
373 | use AnyEvent; |
450 | use AnyEvent; |
374 | use AnyEvent::Util (); |
451 | use AnyEvent::Util (); |
375 | |
452 | |
376 | use IO::FDPass; |
453 | use IO::FDPass; |
377 | |
454 | |
378 | our $VERSION = 0.6; |
455 | our $VERSION = 1.2; |
379 | |
456 | |
380 | # the early fork template process |
457 | # the early fork template process |
381 | our $EARLY; |
458 | our $EARLY; |
382 | |
459 | |
383 | # the empty template process |
460 | # the empty template process |
… | |
… | |
431 | # send string |
508 | # send string |
432 | my $len = syswrite $self->[FH], $self->[QUEUE][0]; |
509 | my $len = syswrite $self->[FH], $self->[QUEUE][0]; |
433 | |
510 | |
434 | unless ($len) { |
511 | unless ($len) { |
435 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
512 | return if $! == Errno::EAGAIN || $! == Errno::EWOULDBLOCK; |
436 | undef $self->[3]; |
513 | undef $self->[WW]; |
437 | die "AnyEvent::Fork: command write failure: $!"; |
514 | die "AnyEvent::Fork: command write failure: $!"; |
438 | } |
515 | } |
439 | |
516 | |
440 | substr $self->[QUEUE][0], 0, $len, ""; |
517 | substr $self->[QUEUE][0], 0, $len, ""; |
441 | shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; |
518 | shift @{ $self->[QUEUE] } unless length $self->[QUEUE][0]; |
… | |
… | |
444 | |
521 | |
445 | # everything written |
522 | # everything written |
446 | undef $self->[WW]; |
523 | undef $self->[WW]; |
447 | |
524 | |
448 | # invoke run callback, if any |
525 | # invoke run callback, if any |
|
|
526 | if ($self->[CB]) { |
449 | $self->[CB]->($self->[FH]) if $self->[CB]; |
527 | $self->[CB]->($self->[FH]); |
|
|
528 | @$self = (); |
|
|
529 | } |
450 | }; |
530 | }; |
451 | |
531 | |
452 | () # make sure we don't leak the watcher |
532 | () # make sure we don't leak the watcher |
453 | } |
533 | } |
454 | |
534 | |
… | |
… | |
525 | |
605 | |
526 | You should use C<new> whenever possible, except when having a template |
606 | You should use C<new> whenever possible, except when having a template |
527 | process around is unacceptable. |
607 | process around is unacceptable. |
528 | |
608 | |
529 | The path to the perl interpreter is divined using various methods - first |
609 | The path to the perl interpreter is divined using various methods - first |
530 | C<$^X> is investigated to see if the path ends with something that sounds |
610 | C<$^X> is investigated to see if the path ends with something that looks |
531 | as if it were the perl interpreter. Failing this, the module falls back to |
611 | as if it were the perl interpreter. Failing this, the module falls back to |
532 | using C<$Config::Config{perlpath}>. |
612 | using C<$Config::Config{perlpath}>. |
533 | |
613 | |
|
|
614 | The path to perl can also be overriden by setting the global variable |
|
|
615 | C<$AnyEvent::Fork::PERL> - it's value will be used for all subsequent |
|
|
616 | invocations. |
|
|
617 | |
534 | =cut |
618 | =cut |
|
|
619 | |
|
|
620 | our $PERL; |
535 | |
621 | |
536 | sub new_exec { |
622 | sub new_exec { |
537 | my ($self) = @_; |
623 | my ($self) = @_; |
538 | |
624 | |
539 | return $EARLY->fork |
625 | return $EARLY->fork |
540 | if $EARLY; |
626 | if $EARLY; |
541 | |
627 | |
|
|
628 | unless (defined $PERL) { |
542 | # first find path of perl |
629 | # first find path of perl |
543 | my $perl = $; |
630 | my $perl = $; |
544 | |
631 | |
545 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
632 | # first we try $^X, but the path must be absolute (always on win32), and end in sth. |
546 | # that looks like perl. this obviously only works for posix and win32 |
633 | # that looks like perl. this obviously only works for posix and win32 |
547 | unless ( |
634 | unless ( |
548 | ($^O eq "MSWin32" || $perl =~ m%^/%) |
635 | ($^O eq "MSWin32" || $perl =~ m%^/%) |
549 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
636 | && $perl =~ m%[/\\]perl(?:[0-9]+(\.[0-9]+)+)?(\.exe)?$%i |
550 | ) { |
637 | ) { |
551 | # if it doesn't look perlish enough, try Config |
638 | # if it doesn't look perlish enough, try Config |
552 | require Config; |
639 | require Config; |
553 | $perl = $Config::Config{perlpath}; |
640 | $perl = $Config::Config{perlpath}; |
554 | $perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/; |
641 | $perl =~ s/(?:\Q$Config::Config{_exe}\E)?$/$Config::Config{_exe}/; |
|
|
642 | } |
|
|
643 | |
|
|
644 | $PERL = $perl; |
555 | } |
645 | } |
556 | |
646 | |
557 | require Proc::FastSpawn; |
647 | require Proc::FastSpawn; |
558 | |
648 | |
559 | my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
649 | my ($fh, $slave) = AnyEvent::Util::portable_socketpair; |
… | |
… | |
567 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
657 | #local $ENV{PERL5LIB} = join ":", grep !ref, @INC; |
568 | my %env = %ENV; |
658 | my %env = %ENV; |
569 | $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; |
659 | $env{PERL5LIB} = join +($^O eq "MSWin32" ? ";" : ":"), grep !ref, @INC; |
570 | |
660 | |
571 | my $pid = Proc::FastSpawn::spawn ( |
661 | my $pid = Proc::FastSpawn::spawn ( |
572 | $perl, |
662 | $PERL, |
573 | ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
663 | ["perl", "-MAnyEvent::Fork::Serve", "-e", "AnyEvent::Fork::Serve::me", fileno $slave, $$], |
574 | [map "$_=$env{$_}", keys %env], |
664 | [map "$_=$env{$_}", keys %env], |
575 | ) or die "unable to spawn AnyEvent::Fork server: $!"; |
665 | ) or die "unable to spawn AnyEvent::Fork server: $!"; |
576 | |
666 | |
577 | $self->_new ($fh, $pid) |
667 | $self->_new ($fh, $pid) |
578 | } |
668 | } |
579 | |
669 | |
580 | =item $pid = $proc->pid |
670 | =item $pid = $proc->pid |
581 | |
671 | |
582 | Returns the process id of the process I<iff it is a direct child of the |
672 | Returns the process id of the process I<iff it is a direct child of the |
583 | process running AnyEvent::Fork>, and C<undef> otherwise. |
673 | process running AnyEvent::Fork>, and C<undef> otherwise. As a general |
|
|
674 | rule (that you cannot rely upon), processes created via C<new_exec>, |
|
|
675 | L<AnyEvent::Fork::Early> or L<AnyEvent::Fork::Template> are direct |
|
|
676 | children, while all other processes are not. |
584 | |
677 | |
585 | Normally, only processes created via C<< AnyEvent::Fork->new_exec >> and |
678 | Or in other words, you do not normally have to take care of zombies for |
586 | L<AnyEvent::Fork::Template> are direct children, and you are responsible |
679 | processes created via C<new>, but when in doubt, or zombies are a problem, |
587 | to clean up their zombies when they die. |
680 | you need to check whether a process is a diretc child by calling this |
588 | |
681 | method, and possibly creating a child watcher or reap it manually. |
589 | All other processes are not direct children, and will be cleaned up by |
|
|
590 | AnyEvent::Fork itself. |
|
|
591 | |
682 | |
592 | =cut |
683 | =cut |
593 | |
684 | |
594 | sub pid { |
685 | sub pid { |
595 | $_[0][PID] |
686 | $_[0][PID] |
… | |
… | |
726 | |
817 | |
727 | Even if not used otherwise, the socket can be a good indicator for the |
818 | Even if not used otherwise, the socket can be a good indicator for the |
728 | existence of the process - if the other process exits, you get a readable |
819 | existence of the process - if the other process exits, you get a readable |
729 | event on it, because exiting the process closes the socket (if it didn't |
820 | event on it, because exiting the process closes the socket (if it didn't |
730 | create any children using fork). |
821 | create any children using fork). |
|
|
822 | |
|
|
823 | =over 4 |
|
|
824 | |
|
|
825 | =item Compatibility to L<AnyEvent::Fork::Remote> |
|
|
826 | |
|
|
827 | If you want to write code that works with both this module and |
|
|
828 | L<AnyEvent::Fork::Remote>, you need to write your code so that it assumes |
|
|
829 | there are two file handles for communications, which might not be unix |
|
|
830 | domain sockets. The C<run> function should start like this: |
|
|
831 | |
|
|
832 | sub run { |
|
|
833 | my ($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 | |
|
|
839 | This checks whether the passed file handle is, in fact, the process |
|
|
840 | C<STDIN> handle. If it is, then the function was invoked visa |
|
|
841 | L<AnyEvent::Fork::Remote>, so STDIN should be used for reading and |
|
|
842 | C<STDOUT> should be used for writing. |
|
|
843 | |
|
|
844 | In all other cases, the function was called via this module, and there is |
|
|
845 | only one file handle that should be sued for reading and writing. |
|
|
846 | |
|
|
847 | =back |
731 | |
848 | |
732 | Example: create a template for a process pool, pass a few strings, some |
849 | Example: create a template for a process pool, pass a few strings, some |
733 | file handles, then fork, pass one more string, and run some code. |
850 | file handles, then fork, pass one more string, and run some code. |
734 | |
851 | |
735 | my $pool = AnyEvent::Fork |
852 | my $pool = AnyEvent::Fork |
… | |
… | |
769 | $self->_cmd (r => $func); |
886 | $self->_cmd (r => $func); |
770 | } |
887 | } |
771 | |
888 | |
772 | =back |
889 | =back |
773 | |
890 | |
|
|
891 | =head2 EXPERIMENTAL METHODS |
|
|
892 | |
|
|
893 | These 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 |
|
|
898 | |
|
|
899 | Flushes all commands out to the process and then calls the callback with |
|
|
900 | the communications socket. |
|
|
901 | |
|
|
902 | The process object becomes unusable on return from this function - any |
|
|
903 | further method calls result in undefined behaviour. |
|
|
904 | |
|
|
905 | The point of this method is to give you a file handle that you can pass |
|
|
906 | to another process. In that other process, you can call C<new_from_fh |
|
|
907 | AnyEvent::Fork $fh> to create a new C<AnyEvent::Fork> object from it, |
|
|
908 | thereby effectively passing a fork object to another process. |
|
|
909 | |
|
|
910 | =cut |
|
|
911 | |
|
|
912 | sub to_fh { |
|
|
913 | my ($self, $cb) = @_; |
|
|
914 | |
|
|
915 | $self->[CB] = $cb; |
|
|
916 | |
|
|
917 | unless ($self->[WW]) { |
|
|
918 | $self->[CB]->($self->[FH]); |
|
|
919 | @$self = (); |
|
|
920 | } |
|
|
921 | } |
|
|
922 | |
|
|
923 | =item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED |
|
|
924 | |
|
|
925 | Takes a file handle originally rceeived by the C<to_fh> method and creates |
|
|
926 | a new C<AnyEvent:Fork> object. The child process itself will not change in |
|
|
927 | any way, i.e. it will keep all the modifications done to it before calling |
|
|
928 | C<to_fh>. |
|
|
929 | |
|
|
930 | The new object is very much like the original object, except that the |
|
|
931 | C<pid> method will return C<undef> even if the process is a direct child. |
|
|
932 | |
|
|
933 | =cut |
|
|
934 | |
|
|
935 | sub new_from_fh { |
|
|
936 | my ($class, $fh) = @_; |
|
|
937 | |
|
|
938 | $class->_new ($fh) |
|
|
939 | } |
|
|
940 | |
|
|
941 | =back |
|
|
942 | |
774 | =head1 PERFORMANCE |
943 | =head1 PERFORMANCE |
775 | |
944 | |
776 | Now for some unscientific benchmark numbers (all done on an amd64 |
945 | Now for some unscientific benchmark numbers (all done on an amd64 |
777 | GNU/Linux box). These are intended to give you an idea of the relative |
946 | GNU/Linux box). These are intended to give you an idea of the relative |
778 | performance you can expect, they are not meant to be absolute performance |
947 | performance you can expect, they are not meant to be absolute performance |
… | |
… | |
784 | |
953 | |
785 | 2079 new processes per second, using manual socketpair + fork |
954 | 2079 new processes per second, using manual socketpair + fork |
786 | |
955 | |
787 | Then I did the same thing, but instead of calling fork, I called |
956 | Then I did the same thing, but instead of calling fork, I called |
788 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
957 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
789 | socket form the child to close on exit. This does the same thing as manual |
958 | socket from the child to close on exit. This does the same thing as manual |
790 | socket pair + fork, except that what is forked is the template process |
959 | socket pair + fork, except that what is forked is the template process |
791 | (2440kB), and the socket needs to be passed to the server at the other end |
960 | (2440kB), and the socket needs to be passed to the server at the other end |
792 | of the socket first. |
961 | of the socket first. |
793 | |
962 | |
794 | 2307 new processes per second, using AnyEvent::Fork->new |
963 | 2307 new processes per second, using AnyEvent::Fork->new |
… | |
… | |
901 | to make it so, mostly due to the bloody broken perl that nobody seems to |
1070 | to make it so, mostly due to the bloody broken perl that nobody seems to |
902 | care about. The fork emulation is a bad joke - I have yet to see something |
1071 | care about. The fork emulation is a bad joke - I have yet to see something |
903 | useful that you can do with it without running into memory corruption |
1072 | useful that you can do with it without running into memory corruption |
904 | issues or other braindamage. Hrrrr. |
1073 | issues or other braindamage. Hrrrr. |
905 | |
1074 | |
|
|
1075 | Since fork is endlessly broken on win32 perls (it doesn't even remotely |
|
|
1076 | work within it's documented limits) and quite obviously it's not getting |
|
|
1077 | improved any time soon, the best way to proceed on windows would be to |
|
|
1078 | always use C<new_exec> and thus never rely on perl's fork "emulation". |
|
|
1079 | |
906 | Cygwin perl is not supported at the moment due to some hilarious |
1080 | Cygwin perl is not supported at the moment due to some hilarious |
907 | shortcomings of its API - see L<IO::FDPoll> for more details. |
1081 | shortcomings of its API - see L<IO::FDPoll> for more details. If you never |
|
|
1082 | use C<send_fh> and always use C<new_exec> to create processes, it should |
|
|
1083 | work though. |
908 | |
1084 | |
909 | =head1 SEE ALSO |
1085 | =head1 SEE ALSO |
910 | |
1086 | |
911 | L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter), |
1087 | L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all |
|
|
1088 | (part of this distribution). |
|
|
1089 | |
912 | L<AnyEvent::Fork::Template> (to create a process by forking the main |
1090 | L<AnyEvent::Fork::Template>, to create a process by forking the main |
913 | program at a convenient time), L<AnyEvent::Fork::RPC> (for simple RPC to |
1091 | program at a convenient time (part of this distribution). |
914 | child processes). |
1092 | |
|
|
1093 | L<AnyEvent::Fork::Remote>, for another way to create processes that is |
|
|
1094 | mostly compatible to this module and modules building on top of it, but |
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1095 | works better with remote processes. |
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1096 | |
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1097 | L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). |
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1098 | |
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1099 | L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN). |
915 | |
1100 | |
916 | =head1 AUTHOR AND CONTACT INFORMATION |
1101 | =head1 AUTHOR AND CONTACT INFORMATION |
917 | |
1102 | |
918 | Marc Lehmann <schmorp@schmorp.de> |
1103 | Marc Lehmann <schmorp@schmorp.de> |
919 | http://software.schmorp.de/pkg/AnyEvent-Fork |
1104 | http://software.schmorp.de/pkg/AnyEvent-Fork |