… | |
… | |
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 |
|
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267 | ->new |
|
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268 | ->eval (do { local $/; <DATA> }) |
|
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269 | ->run ("doit", sub { ... }); |
|
|
270 | |
|
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271 | __DATA__ |
|
|
272 | |
|
|
273 | sub doit { |
|
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274 | ... do something! |
|
|
275 | } |
|
|
276 | |
|
|
277 | =head2 For stingy standalone programs: do not rely on external files at |
|
|
278 | all. |
|
|
279 | |
|
|
280 | For single-file scripts it can be inconvenient to rely on external |
|
|
281 | files - even when using < C<DATA> section, you still need to C<exec> |
|
|
282 | an external perl interpreter, which might not be available when using |
|
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283 | L<App::Staticperl>, L<Urlader> or L<PAR::Packer> for example. |
|
|
284 | |
|
|
285 | Two modules help here - L<AnyEvent::Fork::Early> forks a template process |
|
|
286 | for all further calls to C<new_exec>, and L<AnyEvent::Fork::Template> |
|
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287 | forks the main program as a template process. |
|
|
288 | |
|
|
289 | Here is how your main program should look like: |
|
|
290 | |
|
|
291 | #! perl |
|
|
292 | |
|
|
293 | # optional, as the very first thing. |
|
|
294 | # in case modules want to create their own processes. |
|
|
295 | use AnyEvent::Fork::Early; |
|
|
296 | |
|
|
297 | # next, load all modules you need in your template process |
|
|
298 | use Example::My::Module |
|
|
299 | use Example::Whatever; |
|
|
300 | |
|
|
301 | # next, put your run function definition and anything else you |
|
|
302 | # need, but do not use code outside of BEGIN blocks. |
|
|
303 | sub worker_run { |
|
|
304 | my ($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 = '1.0'; |
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 | |
… | |
… | |
767 | |
847 | |
768 | $self->[CB] = $cb; |
848 | $self->[CB] = $cb; |
769 | $self->_cmd (r => $func); |
849 | $self->_cmd (r => $func); |
770 | } |
850 | } |
771 | |
851 | |
|
|
852 | =item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED |
|
|
853 | |
|
|
854 | Flushes all commands out to the process and then calls the callback with |
|
|
855 | the communications socket. |
|
|
856 | |
|
|
857 | The process object becomes unusable on return from this function - any |
|
|
858 | further method calls result in undefined behaviour. |
|
|
859 | |
|
|
860 | The point of this method is to give you a file handle thta you cna pass |
|
|
861 | to another process. In that other process, you can call C<new_from_fh |
|
|
862 | AnyEvent::Fork> to create a new C<AnyEvent::Fork> object from it, thereby |
|
|
863 | effectively passing a fork object to another process. |
|
|
864 | |
|
|
865 | =cut |
|
|
866 | |
|
|
867 | sub to_fh { |
|
|
868 | my ($self, $cb) = @_; |
|
|
869 | |
|
|
870 | $self->[CB] = $cb; |
|
|
871 | |
|
|
872 | unless ($self->[WW]) { |
|
|
873 | $self->[CB]->($self->[FH]); |
|
|
874 | @$self = (); |
|
|
875 | } |
|
|
876 | } |
|
|
877 | |
|
|
878 | =item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED |
|
|
879 | |
|
|
880 | Takes a file handle originally rceeived by the C<to_fh> method and creates |
|
|
881 | a new C<AnyEvent:Fork> object. The child process itself will not change in |
|
|
882 | any way, i.e. it will keep all the modifications done to it before calling |
|
|
883 | C<to_fh>. |
|
|
884 | |
|
|
885 | The new object is very much like the original object, except that the |
|
|
886 | C<pid> method will return C<undef> even if the process is a direct child. |
|
|
887 | |
|
|
888 | =cut |
|
|
889 | |
|
|
890 | sub new_from_fh { |
|
|
891 | my ($class, $fh) = @_; |
|
|
892 | |
|
|
893 | $class->_new ($fh) |
|
|
894 | } |
|
|
895 | |
772 | =back |
896 | =back |
773 | |
897 | |
774 | =head1 PERFORMANCE |
898 | =head1 PERFORMANCE |
775 | |
899 | |
776 | Now for some unscientific benchmark numbers (all done on an amd64 |
900 | Now for some unscientific benchmark numbers (all done on an amd64 |
… | |
… | |
784 | |
908 | |
785 | 2079 new processes per second, using manual socketpair + fork |
909 | 2079 new processes per second, using manual socketpair + fork |
786 | |
910 | |
787 | Then I did the same thing, but instead of calling fork, I called |
911 | 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 |
912 | 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 |
913 | 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 |
914 | 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 |
915 | (2440kB), and the socket needs to be passed to the server at the other end |
792 | of the socket first. |
916 | of the socket first. |
793 | |
917 | |
794 | 2307 new processes per second, using AnyEvent::Fork->new |
918 | 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 |
1025 | 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 |
1026 | 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 |
1027 | useful that you can do with it without running into memory corruption |
904 | issues or other braindamage. Hrrrr. |
1028 | issues or other braindamage. Hrrrr. |
905 | |
1029 | |
|
|
1030 | Since fork is endlessly broken on win32 perls (it doesn't even remotely |
|
|
1031 | work within it's documented limits) and quite obviously it's not getting |
|
|
1032 | improved any time soon, the best way to proceed on windows would be to |
|
|
1033 | always use C<new_exec> and thus never rely on perl's fork "emulation". |
|
|
1034 | |
906 | Cygwin perl is not supported at the moment due to some hilarious |
1035 | Cygwin perl is not supported at the moment due to some hilarious |
907 | shortcomings of its API - see L<IO::FDPoll> for more details. |
1036 | shortcomings of its API - see L<IO::FDPoll> for more details. If you never |
|
|
1037 | use C<send_fh> and always use C<new_exec> to create processes, it should |
|
|
1038 | work though. |
908 | |
1039 | |
909 | =head1 SEE ALSO |
1040 | =head1 SEE ALSO |
910 | |
1041 | |
911 | L<AnyEvent::Fork::Early> (to avoid executing a perl interpreter), |
1042 | L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all |
|
|
1043 | (part of this distribution). |
|
|
1044 | |
912 | L<AnyEvent::Fork::Template> (to create a process by forking the main |
1045 | 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 |
1046 | program at a convenient time (part of this distribution). |
914 | child processes). |
1047 | |
|
|
1048 | L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). |
|
|
1049 | |
|
|
1050 | L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN). |
915 | |
1051 | |
916 | =head1 AUTHOR AND CONTACT INFORMATION |
1052 | =head1 AUTHOR AND CONTACT INFORMATION |
917 | |
1053 | |
918 | Marc Lehmann <schmorp@schmorp.de> |
1054 | Marc Lehmann <schmorp@schmorp.de> |
919 | http://software.schmorp.de/pkg/AnyEvent-Fork |
1055 | http://software.schmorp.de/pkg/AnyEvent-Fork |