| 1 | =head1 NAME |
1 | =head1 NAME |
| 2 | |
2 | |
| 3 | AnyEvent::Fork::RPC - simple RPC extension for AnyEvent::Fork |
3 | AnyEvent::Fork::RPC - simple RPC extension for AnyEvent::Fork |
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4 | |
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5 | THE API IS NOT FINISHED, CONSIDER THIS A BETA RELEASE |
| 4 | |
6 | |
| 5 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
| 6 | |
8 | |
| 7 | use AnyEvent::Fork::RPC; |
9 | use AnyEvent::Fork::RPC; |
| 8 | # use AnyEvent::Fork is not needed |
10 | # use AnyEvent::Fork is not needed |
| … | |
… | |
| 11 | ->new |
13 | ->new |
| 12 | ->require ("MyModule") |
14 | ->require ("MyModule") |
| 13 | ->AnyEvent::Fork::RPC::run ( |
15 | ->AnyEvent::Fork::RPC::run ( |
| 14 | "MyModule::server", |
16 | "MyModule::server", |
| 15 | ); |
17 | ); |
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18 | |
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19 | use AnyEvent; |
| 16 | |
20 | |
| 17 | my $cv = AE::cv; |
21 | my $cv = AE::cv; |
| 18 | |
22 | |
| 19 | $rpc->(1, 2, 3, sub { |
23 | $rpc->(1, 2, 3, sub { |
| 20 | print "MyModule::server returned @_\n"; |
24 | print "MyModule::server returned @_\n"; |
| … | |
… | |
| 301 | |
305 | |
| 302 | use Errno (); |
306 | use Errno (); |
| 303 | use Guard (); |
307 | use Guard (); |
| 304 | |
308 | |
| 305 | use AnyEvent; |
309 | use AnyEvent; |
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310 | # explicit version on next line, as some cpan-testers test with the 0.1 version, |
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311 | # ignoring dependencies, and this line will at least give a clear indication of that. |
| 306 | use AnyEvent::Fork; # we don't actually depend on it, this is for convenience |
312 | use AnyEvent::Fork 0.6; # we don't actually depend on it, this is for convenience |
| 307 | |
313 | |
| 308 | our $VERSION = 0.1; |
314 | our $VERSION = 0.2; |
| 309 | |
315 | |
| 310 | =item my $rpc = AnyEvent::Fork::RPC::run $fork, $function, [key => value...] |
316 | =item my $rpc = AnyEvent::Fork::RPC::run $fork, $function, [key => value...] |
| 311 | |
317 | |
| 312 | The traditional way to call it. But it is way cooler to call it in the |
318 | The traditional way to call it. But it is way cooler to call it in the |
| 313 | following way: |
319 | following way: |
| … | |
… | |
| 372 | |
378 | |
| 373 | The default server used in the child does all I/O blockingly, and only |
379 | The default server used in the child does all I/O blockingly, and only |
| 374 | allows a single RPC call to execute concurrently. |
380 | allows a single RPC call to execute concurrently. |
| 375 | |
381 | |
| 376 | Setting C<async> to a true value switches to another implementation that |
382 | Setting C<async> to a true value switches to another implementation that |
| 377 | uses L<AnyEvent> in the child and allows multiple concurrent RPC calls. |
383 | uses L<AnyEvent> in the child and allows multiple concurrent RPC calls (it |
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384 | does not support recursion in the event loop however, blocking condvar |
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385 | calls will fail). |
| 378 | |
386 | |
| 379 | The actual API in the child is documented in the section that describes |
387 | The actual API in the child is documented in the section that describes |
| 380 | the calling semantics of the returned C<$rpc> function. |
388 | the calling semantics of the returned C<$rpc> function. |
| 381 | |
389 | |
| 382 | If you want to pre-load the actual back-end modules to enable memory |
390 | If you want to pre-load the actual back-end modules to enable memory |
| … | |
… | |
| 384 | synchronous, and C<AnyEvent::Fork::RPC::Async> for asynchronous mode. |
392 | synchronous, and C<AnyEvent::Fork::RPC::Async> for asynchronous mode. |
| 385 | |
393 | |
| 386 | If you use a template process and want to fork both sync and async |
394 | If you use a template process and want to fork both sync and async |
| 387 | children, then it is permissible to load both modules. |
395 | children, then it is permissible to load both modules. |
| 388 | |
396 | |
| 389 | =item serialiser => $string (default: '(sub { pack "(w/a*)*", @_ }, sub { unpack "(w/a*)*", shift })') |
397 | =item serialiser => $string (default: $AnyEvent::Fork::RPC::STRING_SERIALISER) |
| 390 | |
398 | |
| 391 | All arguments, result data and event data have to be serialised to be |
399 | All arguments, result data and event data have to be serialised to be |
| 392 | transferred between the processes. For this, they have to be frozen and |
400 | transferred between the processes. For this, they have to be frozen and |
| 393 | thawed in both parent and child processes. |
401 | thawed in both parent and child processes. |
| 394 | |
402 | |
| 395 | By default, only octet strings can be passed between the processes, which |
403 | By default, only octet strings can be passed between the processes, which |
| 396 | is reasonably fast and efficient. |
404 | is reasonably fast and efficient and requires no extra modules. |
| 397 | |
405 | |
| 398 | For more complicated use cases, you can provide your own freeze and thaw |
406 | For more complicated use cases, you can provide your own freeze and thaw |
| 399 | functions, by specifying a string with perl source code. It's supposed to |
407 | functions, by specifying a string with perl source code. It's supposed to |
| 400 | return two code references when evaluated: the first receives a list of |
408 | return two code references when evaluated: the first receives a list of |
| 401 | perl values and must return an octet string. The second receives the octet |
409 | perl values and must return an octet string. The second receives the octet |
| … | |
… | |
| 403 | |
411 | |
| 404 | If you need an external module for serialisation, then you can either |
412 | If you need an external module for serialisation, then you can either |
| 405 | pre-load it into your L<AnyEvent::Fork> process, or you can add a C<use> |
413 | pre-load it into your L<AnyEvent::Fork> process, or you can add a C<use> |
| 406 | or C<require> statement into the serialiser string. Or both. |
414 | or C<require> statement into the serialiser string. Or both. |
| 407 | |
415 | |
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416 | Here are some examples - some of them are also available as global |
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417 | variables that make them easier to use. |
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418 | |
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419 | =over 4 |
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420 | |
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421 | =item octet strings - C<$AnyEvent::Fork::RPC::STRING_SERIALISER> |
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422 | |
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423 | This serialiser concatenates length-prefixes octet strings, and is the |
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424 | default. |
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425 | |
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426 | Implementation: |
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427 | |
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428 | ( |
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429 | sub { pack "(w/a*)*", @_ }, |
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430 | sub { unpack "(w/a*)*", shift } |
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431 | ) |
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432 | |
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433 | =item json - C<$AnyEvent::Fork::RPC::JSON_SERIALISER> |
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434 | |
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435 | This serialiser creates JSON arrays - you have to make sure the L<JSON> |
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436 | module is installed for this serialiser to work. It can be beneficial for |
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437 | sharing when you preload the L<JSON> module in a template process. |
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438 | |
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439 | L<JSON> (with L<JSON::XS> installed) is slower than the octet string |
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440 | serialiser, but usually much faster than L<Storable>, unless big chunks of |
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441 | binary data need to be transferred. |
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442 | |
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443 | Implementation: |
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444 | |
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445 | use JSON (); |
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446 | ( |
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447 | sub { JSON::encode_json \@_ }, |
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448 | sub { @{ JSON::decode_json shift } } |
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449 | ) |
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450 | |
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451 | =item storable - C<$AnyEvent::Fork::RPC::STORABLE_SERIALISER> |
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452 | |
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453 | This serialiser uses L<Storable>, which means it has high chance of |
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454 | serialising just about anything you throw at it, at the cost of having |
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455 | very high overhead per operation. It also comes with perl. |
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456 | |
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457 | Implementation: |
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458 | |
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459 | use Storable (); |
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460 | ( |
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461 | sub { Storable::freeze \@_ }, |
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462 | sub { @{ Storable::thaw shift } } |
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463 | ) |
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464 | |
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465 | =back |
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466 | |
| 408 | =back |
467 | =back |
| 409 | |
468 | |
| 410 | See the examples section earlier in this document for some actual |
469 | See the examples section earlier in this document for some actual |
| 411 | examples. |
470 | examples. |
| 412 | |
471 | |
| 413 | =cut |
472 | =cut |
| 414 | |
473 | |
| 415 | our $STRING_SERIALISER = '(sub { pack "(w/a*)*", @_ }, sub { unpack "(w/a*)*", shift })'; |
474 | our $STRING_SERIALISER = '(sub { pack "(w/a*)*", @_ }, sub { unpack "(w/a*)*", shift })'; |
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475 | our $JSON_SERIALISER = 'use JSON (); (sub { JSON::encode_json \@_ }, sub { @{ JSON::decode_json shift } })'; |
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476 | our $STORABLE_SERIALISER = 'use Storable (); (sub { Storable::freeze \@_ }, sub { @{ Storable::thaw shift } })'; |
| 416 | |
477 | |
| 417 | sub run { |
478 | sub run { |
| 418 | my ($self, $function, %arg) = @_; |
479 | my ($self, $function, %arg) = @_; |
| 419 | |
480 | |
| 420 | my $serialiser = delete $arg{serialiser} || $STRING_SERIALISER; |
481 | my $serialiser = delete $arg{serialiser} || $STRING_SERIALISER; |
| … | |
… | |
| 465 | $rlen = $rlen * 2 + 16 if $rlen - 128 < length $rbuf; |
526 | $rlen = $rlen * 2 + 16 if $rlen - 128 < length $rbuf; |
| 466 | $len = sysread $fh, $rbuf, $rlen - length $rbuf, length $rbuf; |
527 | $len = sysread $fh, $rbuf, $rlen - length $rbuf, length $rbuf; |
| 467 | |
528 | |
| 468 | if ($len) { |
529 | if ($len) { |
| 469 | while (8 <= length $rbuf) { |
530 | while (8 <= length $rbuf) { |
| 470 | ($id, $len) = unpack "LL", $rbuf; |
531 | ($id, $len) = unpack "NN", $rbuf; |
| 471 | 8 + $len <= length $rbuf |
532 | 8 + $len <= length $rbuf |
| 472 | or last; |
533 | or last; |
| 473 | |
534 | |
| 474 | my @r = $t->(substr $rbuf, 8, $len); |
535 | my @r = $t->(substr $rbuf, 8, $len); |
| 475 | substr $rbuf, 0, 8 + $len, ""; |
536 | substr $rbuf, 0, 8 + $len, ""; |
| … | |
… | |
| 491 | undef $rw; undef $ww; # it ends here |
552 | undef $rw; undef $ww; # it ends here |
| 492 | |
553 | |
| 493 | if (@rcb || %rcb) { |
554 | if (@rcb || %rcb) { |
| 494 | $on_error->("unexpected eof"); |
555 | $on_error->("unexpected eof"); |
| 495 | } else { |
556 | } else { |
| 496 | $on_destroy->(); |
557 | $on_destroy->() |
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558 | if $on_destroy; |
| 497 | } |
559 | } |
| 498 | } elsif ($! != Errno::EAGAIN && $! != Errno::EWOULDBLOCK) { |
560 | } elsif ($! != Errno::EAGAIN && $! != Errno::EWOULDBLOCK) { |
| 499 | undef $rw; undef $ww; # it ends here |
561 | undef $rw; undef $ww; # it ends here |
| 500 | $on_error->("read: $!"); |
562 | $on_error->("read: $!"); |
| 501 | } |
563 | } |
| … | |
… | |
| 504 | $ww ||= AE::io $fh, 1, $wcb; |
566 | $ww ||= AE::io $fh, 1, $wcb; |
| 505 | }); |
567 | }); |
| 506 | |
568 | |
| 507 | my $guard = Guard::guard { |
569 | my $guard = Guard::guard { |
| 508 | $shutdown = 1; |
570 | $shutdown = 1; |
| 509 | $ww ||= $fh && AE::io $fh, 1, $wcb; |
571 | |
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572 | shutdown $fh, 1 if $fh && !$ww; |
| 510 | }; |
573 | }; |
| 511 | |
574 | |
| 512 | my $id; |
575 | my $id; |
| 513 | |
576 | |
| 514 | $arg{async} |
577 | $arg{async} |
| … | |
… | |
| 516 | $id = ($id == 0xffffffff ? 0 : $id) + 1; |
579 | $id = ($id == 0xffffffff ? 0 : $id) + 1; |
| 517 | $id = ($id == 0xffffffff ? 0 : $id) + 1 while exists $rcb{$id}; # rarely loops |
580 | $id = ($id == 0xffffffff ? 0 : $id) + 1 while exists $rcb{$id}; # rarely loops |
| 518 | |
581 | |
| 519 | $rcb{$id} = pop; |
582 | $rcb{$id} = pop; |
| 520 | |
583 | |
| 521 | $guard; # keep it alive |
584 | $guard if 0; # keep it alive |
| 522 | |
585 | |
| 523 | $wbuf .= pack "LL/a*", $id, &$f; |
586 | $wbuf .= pack "NN/a*", $id, &$f; |
| 524 | $ww ||= $fh && AE::io $fh, 1, $wcb; |
587 | $ww ||= $fh && AE::io $fh, 1, $wcb; |
| 525 | } |
588 | } |
| 526 | : sub { |
589 | : sub { |
| 527 | push @rcb, pop; |
590 | push @rcb, pop; |
| 528 | |
591 | |
| 529 | $guard; # keep it alive |
592 | $guard; # keep it alive |
| 530 | |
593 | |
| 531 | $wbuf .= pack "L/a*", &$f; |
594 | $wbuf .= pack "N/a*", &$f; |
| 532 | $ww ||= $fh && AE::io $fh, 1, $wcb; |
595 | $ww ||= $fh && AE::io $fh, 1, $wcb; |
| 533 | } |
596 | } |
| 534 | } |
597 | } |
| 535 | |
598 | |
| 536 | =item $rpc->(..., $cb->(...)) |
599 | =item $rpc->(..., $cb->(...)) |
| … | |
… | |
| 640 | are queued and the jobs are slow, they will all run concurrently. The |
703 | are queued and the jobs are slow, they will all run concurrently. The |
| 641 | child must implement some queueing/limiting mechanism if this causes |
704 | child must implement some queueing/limiting mechanism if this causes |
| 642 | problems. Alternatively, the parent could limit the amount of rpc calls |
705 | problems. Alternatively, the parent could limit the amount of rpc calls |
| 643 | that are outstanding. |
706 | that are outstanding. |
| 644 | |
707 | |
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708 | Blocking use of condvars is not supported. |
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709 | |
| 645 | Using event-based modules such as L<IO::AIO>, L<Gtk2>, L<Tk> and so on is |
710 | Using event-based modules such as L<IO::AIO>, L<Gtk2>, L<Tk> and so on is |
| 646 | easy. |
711 | easy. |
| 647 | |
712 | |
| 648 | =back |
713 | =back |
| 649 | |
714 | |
| … | |
… | |
| 710 | |
775 | |
| 711 | Of course, this might be blocking if you pass a lot of file descriptors, |
776 | Of course, this might be blocking if you pass a lot of file descriptors, |
| 712 | so you might want to look into L<AnyEvent::FDpasser> which can handle the |
777 | so you might want to look into L<AnyEvent::FDpasser> which can handle the |
| 713 | gory details. |
778 | gory details. |
| 714 | |
779 | |
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780 | =head1 EXCEPTIONS |
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781 | |
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782 | There are no provisions whatsoever for catching exceptions at this time - |
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783 | in the child, exeptions might kill the process, causing calls to be lost |
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784 | and the parent encountering a fatal error. In the parent, exceptions in |
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785 | the result callback will not be caught and cause undefined behaviour. |
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786 | |
| 715 | =head1 SEE ALSO |
787 | =head1 SEE ALSO |
| 716 | |
788 | |
| 717 | L<AnyEvent::Fork> (to create the processes in the first place), |
789 | L<AnyEvent::Fork>, to create the processes in the first place. |
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790 | |
| 718 | L<AnyEvent::Fork::Pool> (to manage whole pools of processes). |
791 | L<AnyEvent::Fork::Pool>, to manage whole pools of processes. |
| 719 | |
792 | |
| 720 | =head1 AUTHOR AND CONTACT INFORMATION |
793 | =head1 AUTHOR AND CONTACT INFORMATION |
| 721 | |
794 | |
| 722 | Marc Lehmann <schmorp@schmorp.de> |
795 | Marc Lehmann <schmorp@schmorp.de> |
| 723 | http://software.schmorp.de/pkg/AnyEvent-Fork-RPC |
796 | http://software.schmorp.de/pkg/AnyEvent-Fork-RPC |
