… | |
… | |
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. |
259 | |
332 | |
… | |
… | |
377 | use AnyEvent; |
450 | use AnyEvent; |
378 | use AnyEvent::Util (); |
451 | use AnyEvent::Util (); |
379 | |
452 | |
380 | use IO::FDPass; |
453 | use IO::FDPass; |
381 | |
454 | |
382 | our $VERSION = 0.7; |
455 | our $VERSION = '1.0'; |
383 | |
456 | |
384 | # the early fork template process |
457 | # the early fork template process |
385 | our $EARLY; |
458 | our $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]; |
… | |
… | |
448 | |
521 | |
449 | # everything written |
522 | # everything written |
450 | undef $self->[WW]; |
523 | undef $self->[WW]; |
451 | |
524 | |
452 | # invoke run callback, if any |
525 | # invoke run callback, if any |
|
|
526 | if ($self->[CB]) { |
453 | $self->[CB]->($self->[FH]) if $self->[CB]; |
527 | $self->[CB]->($self->[FH]); |
|
|
528 | @$self = (); |
|
|
529 | } |
454 | }; |
530 | }; |
455 | |
531 | |
456 | () # make sure we don't leak the watcher |
532 | () # make sure we don't leak the watcher |
457 | } |
533 | } |
458 | |
534 | |
… | |
… | |
773 | $self->_cmd (r => $func); |
849 | $self->_cmd (r => $func); |
774 | } |
850 | } |
775 | |
851 | |
776 | =back |
852 | =back |
777 | |
853 | |
|
|
854 | =head2 ADVANCED METHODS |
|
|
855 | |
|
|
856 | =over 4 |
|
|
857 | |
|
|
858 | =item new_from_stdio AnyEvent::Fork $fh |
|
|
859 | |
|
|
860 | Assume that you have a perl interpreter running (without any special |
|
|
861 | options or a program) somewhere and it has it's STDIN and STDOUT connected |
|
|
862 | to the C<$fh> somehow. I.e. exactly the state perl is in when you start it |
|
|
863 | without any arguments: |
|
|
864 | |
|
|
865 | perl |
|
|
866 | |
|
|
867 | Then you can create an C<AnyEvent::Fork> object out of this perl |
|
|
868 | interpreter with this constructor. |
|
|
869 | |
|
|
870 | When the usefulness of this isn't immediately clear, imagine you manage to |
|
|
871 | run a perl interpreter remotely (F<ssh remotemachine perl>), then you can |
|
|
872 | manage it mostly like a local C<AnyEvent::Fork> child. |
|
|
873 | |
|
|
874 | This works without any module support, i.e. the remote F<perl> does not |
|
|
875 | need to have any special modules installed. |
|
|
876 | |
|
|
877 | There are a number of limitations though: C<send_fh> will only work if the |
|
|
878 | L<IO::FDPass> module is loadable by the remote perl and the two processes |
|
|
879 | are connected in a way that let's L<IO::FDPass> do it's work. |
|
|
880 | |
|
|
881 | This will therefore not work over a network conenction. From this follows |
|
|
882 | that C<fork> will also not work under these circumstances, as it relies on |
|
|
883 | C<send_fh> internally. |
|
|
884 | |
|
|
885 | =cut |
|
|
886 | |
|
|
887 | sub new_from_stdio { |
|
|
888 | my ($class, $fh) = @_; |
|
|
889 | |
|
|
890 | my $self = $class->_new ($fh); |
|
|
891 | |
|
|
892 | # send startup code |
|
|
893 | push @{ $self->[QUEUE] }, |
|
|
894 | (do "AnyEvent/Fork/serve.pl") |
|
|
895 | . <<'EOF'; |
|
|
896 | { |
|
|
897 | open my $fh, "+<&0" |
|
|
898 | or die "AnyEvent::Fork::Serve::stdio: unable to open communications socket: $!\n"; |
|
|
899 | open STDIN , ">&2"; |
|
|
900 | open STDOUT, ">&2"; |
|
|
901 | |
|
|
902 | $OWNER = "another process"; |
|
|
903 | $0 = "AnyEvent::Fork/stdio of $OWNER"; |
|
|
904 | |
|
|
905 | @_ = $fh; |
|
|
906 | } |
|
|
907 | |
|
|
908 | &serve; |
|
|
909 | __END__ |
|
|
910 | EOF |
|
|
911 | |
|
|
912 | # the data is only sent when the user requests additional things, which |
|
|
913 | # is likely early enough for our purposes. |
|
|
914 | |
|
|
915 | $self |
|
|
916 | } |
|
|
917 | |
|
|
918 | =back |
|
|
919 | |
|
|
920 | =head2 EXPERIMENTAL METHODS |
|
|
921 | |
|
|
922 | These methods might go away completely or change behaviour, a any time. |
|
|
923 | |
|
|
924 | =over 4 |
|
|
925 | |
|
|
926 | =item $proc->to_fh ($cb->($fh)) # EXPERIMENTAL, MIGHT BE REMOVED |
|
|
927 | |
|
|
928 | Flushes all commands out to the process and then calls the callback with |
|
|
929 | the communications socket. |
|
|
930 | |
|
|
931 | The process object becomes unusable on return from this function - any |
|
|
932 | further method calls result in undefined behaviour. |
|
|
933 | |
|
|
934 | The point of this method is to give you a file handle thta you cna pass |
|
|
935 | to another process. In that other process, you can call C<new_from_fh |
|
|
936 | AnyEvent::Fork> to create a new C<AnyEvent::Fork> object from it, thereby |
|
|
937 | effectively passing a fork object to another process. |
|
|
938 | |
|
|
939 | =cut |
|
|
940 | |
|
|
941 | sub to_fh { |
|
|
942 | my ($self, $cb) = @_; |
|
|
943 | |
|
|
944 | $self->[CB] = $cb; |
|
|
945 | |
|
|
946 | unless ($self->[WW]) { |
|
|
947 | $self->[CB]->($self->[FH]); |
|
|
948 | @$self = (); |
|
|
949 | } |
|
|
950 | } |
|
|
951 | |
|
|
952 | =item new_from_fh AnyEvent::Fork $fh # EXPERIMENTAL, MIGHT BE REMOVED |
|
|
953 | |
|
|
954 | Takes a file handle originally rceeived by the C<to_fh> method and creates |
|
|
955 | a new C<AnyEvent:Fork> object. The child process itself will not change in |
|
|
956 | any way, i.e. it will keep all the modifications done to it before calling |
|
|
957 | C<to_fh>. |
|
|
958 | |
|
|
959 | The new object is very much like the original object, except that the |
|
|
960 | C<pid> method will return C<undef> even if the process is a direct child. |
|
|
961 | |
|
|
962 | =cut |
|
|
963 | |
|
|
964 | sub new_from_fh { |
|
|
965 | my ($class, $fh) = @_; |
|
|
966 | |
|
|
967 | $class->_new ($fh) |
|
|
968 | } |
|
|
969 | |
|
|
970 | =back |
|
|
971 | |
778 | =head1 PERFORMANCE |
972 | =head1 PERFORMANCE |
779 | |
973 | |
780 | Now for some unscientific benchmark numbers (all done on an amd64 |
974 | Now for some unscientific benchmark numbers (all done on an amd64 |
781 | GNU/Linux box). These are intended to give you an idea of the relative |
975 | GNU/Linux box). These are intended to give you an idea of the relative |
782 | performance you can expect, they are not meant to be absolute performance |
976 | performance you can expect, they are not meant to be absolute performance |
… | |
… | |
788 | |
982 | |
789 | 2079 new processes per second, using manual socketpair + fork |
983 | 2079 new processes per second, using manual socketpair + fork |
790 | |
984 | |
791 | Then I did the same thing, but instead of calling fork, I called |
985 | Then I did the same thing, but instead of calling fork, I called |
792 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
986 | AnyEvent::Fork->new->run ("CORE::exit") and then again waited for the |
793 | socket form the child to close on exit. This does the same thing as manual |
987 | socket from the child to close on exit. This does the same thing as manual |
794 | socket pair + fork, except that what is forked is the template process |
988 | socket pair + fork, except that what is forked is the template process |
795 | (2440kB), and the socket needs to be passed to the server at the other end |
989 | (2440kB), and the socket needs to be passed to the server at the other end |
796 | of the socket first. |
990 | of the socket first. |
797 | |
991 | |
798 | 2307 new processes per second, using AnyEvent::Fork->new |
992 | 2307 new processes per second, using AnyEvent::Fork->new |
… | |
… | |
905 | to make it so, mostly due to the bloody broken perl that nobody seems to |
1099 | to make it so, mostly due to the bloody broken perl that nobody seems to |
906 | care about. The fork emulation is a bad joke - I have yet to see something |
1100 | care about. The fork emulation is a bad joke - I have yet to see something |
907 | useful that you can do with it without running into memory corruption |
1101 | useful that you can do with it without running into memory corruption |
908 | issues or other braindamage. Hrrrr. |
1102 | issues or other braindamage. Hrrrr. |
909 | |
1103 | |
|
|
1104 | Since fork is endlessly broken on win32 perls (it doesn't even remotely |
|
|
1105 | work within it's documented limits) and quite obviously it's not getting |
|
|
1106 | improved any time soon, the best way to proceed on windows would be to |
|
|
1107 | always use C<new_exec> and thus never rely on perl's fork "emulation". |
|
|
1108 | |
910 | Cygwin perl is not supported at the moment due to some hilarious |
1109 | Cygwin perl is not supported at the moment due to some hilarious |
911 | shortcomings of its API - see L<IO::FDPoll> for more details. |
1110 | shortcomings of its API - see L<IO::FDPoll> for more details. If you never |
|
|
1111 | use C<send_fh> and always use C<new_exec> to create processes, it should |
|
|
1112 | work though. |
912 | |
1113 | |
913 | =head1 SEE ALSO |
1114 | =head1 SEE ALSO |
914 | |
1115 | |
915 | L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all |
1116 | L<AnyEvent::Fork::Early>, to avoid executing a perl interpreter at all |
916 | (part of this distribution). |
1117 | (part of this distribution). |
… | |
… | |
918 | L<AnyEvent::Fork::Template>, to create a process by forking the main |
1119 | L<AnyEvent::Fork::Template>, to create a process by forking the main |
919 | program at a convenient time (part of this distribution). |
1120 | program at a convenient time (part of this distribution). |
920 | |
1121 | |
921 | L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). |
1122 | L<AnyEvent::Fork::RPC>, for simple RPC to child processes (on CPAN). |
922 | |
1123 | |
|
|
1124 | L<AnyEvent::Fork::Pool>, for simple worker process pool (on CPAN). |
|
|
1125 | |
923 | =head1 AUTHOR AND CONTACT INFORMATION |
1126 | =head1 AUTHOR AND CONTACT INFORMATION |
924 | |
1127 | |
925 | Marc Lehmann <schmorp@schmorp.de> |
1128 | Marc Lehmann <schmorp@schmorp.de> |
926 | http://software.schmorp.de/pkg/AnyEvent-Fork |
1129 | http://software.schmorp.de/pkg/AnyEvent-Fork |
927 | |
1130 | |