… | |
… | |
8 | |
8 | |
9 | $NODE # contains this node's noderef |
9 | $NODE # contains this node's noderef |
10 | NODE # returns this node's noderef |
10 | NODE # returns this node's noderef |
11 | NODE $port # returns the noderef of the port |
11 | NODE $port # returns the noderef of the port |
12 | |
12 | |
|
|
13 | $SELF # receiving/own port id in rcv callbacks |
|
|
14 | |
|
|
15 | # ports are message endpoints |
|
|
16 | |
|
|
17 | # sending messages |
13 | snd $port, type => data...; |
18 | snd $port, type => data...; |
|
|
19 | snd $port, @msg; |
|
|
20 | snd @msg_with_first_element_being_a_port; |
14 | |
21 | |
15 | $SELF # receiving/own port id in rcv callbacks |
22 | # miniports |
|
|
23 | my $miniport = port { my @msg = @_; 0 }; |
16 | |
24 | |
|
|
25 | # full ports |
|
|
26 | my $port = port; |
17 | rcv $port, smartmatch => $cb->($port, @msg); |
27 | rcv $port, smartmatch => $cb->(@msg); |
18 | |
|
|
19 | # examples: |
|
|
20 | rcv $port2, ping => sub { snd $_[0], "pong"; 0 }; |
28 | rcv $port, ping => sub { snd $_[0], "pong"; 0 }; |
21 | rcv $port1, pong => sub { warn "pong received\n" }; |
29 | rcv $port, pong => sub { warn "pong received\n"; 0 }; |
22 | snd $port2, ping => $port1; |
30 | |
|
|
31 | # remote ports |
|
|
32 | my $port = spawn $node, $initfunc, @initdata; |
23 | |
33 | |
24 | # more, smarter, matches (_any_ is exported by this module) |
34 | # more, smarter, matches (_any_ is exported by this module) |
25 | rcv $port, [child_died => $pid] => sub { ... |
35 | rcv $port, [child_died => $pid] => sub { ... |
26 | rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3 |
36 | rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3 |
27 | |
|
|
28 | # linking two ports, so they both crash together |
|
|
29 | lnk $port1, $port2; |
|
|
30 | |
37 | |
31 | # monitoring |
38 | # monitoring |
32 | mon $port, $cb->(@msg) # callback is invoked on death |
39 | mon $port, $cb->(@msg) # callback is invoked on death |
33 | mon $port, $otherport # kill otherport on abnormal death |
40 | mon $port, $otherport # kill otherport on abnormal death |
34 | mon $port, $otherport, @msg # send message on death |
41 | mon $port, $otherport, @msg # send message on death |
… | |
… | |
112 | |
119 | |
113 | our $VERSION = '0.1'; |
120 | our $VERSION = '0.1'; |
114 | our @EXPORT = qw( |
121 | our @EXPORT = qw( |
115 | NODE $NODE *SELF node_of _any_ |
122 | NODE $NODE *SELF node_of _any_ |
116 | resolve_node initialise_node |
123 | resolve_node initialise_node |
117 | snd rcv mon kil reg psub |
124 | snd rcv mon kil reg psub spawn |
118 | port |
125 | port |
119 | ); |
126 | ); |
120 | |
127 | |
121 | our $SELF; |
128 | our $SELF; |
122 | |
129 | |
… | |
… | |
305 | $port |
312 | $port |
306 | } |
313 | } |
307 | |
314 | |
308 | =item reg $port, $name |
315 | =item reg $port, $name |
309 | |
316 | |
310 | Registers the given port under the name C<$name>. If the name already |
317 | =item reg $name |
311 | exists it is replaced. |
318 | |
|
|
319 | Registers the given port (or C<$SELF><<< if missing) under the name |
|
|
320 | C<$name>. If the name already exists it is replaced. |
312 | |
321 | |
313 | A port can only be registered under one well known name. |
322 | A port can only be registered under one well known name. |
314 | |
323 | |
315 | A port automatically becomes unregistered when it is killed. |
324 | A port automatically becomes unregistered when it is killed. |
316 | |
325 | |
317 | =cut |
326 | =cut |
318 | |
327 | |
319 | sub reg(@) { |
328 | sub reg(@) { |
320 | my ($port, $name) = @_; |
329 | my $port = @_ > 1 ? shift : $SELF || Carp::croak 'reg: called with one argument only, but $SELF not set,'; |
321 | |
330 | |
322 | $REG{$name} = $port; |
331 | $REG{$_[0]} = $port; |
323 | } |
332 | } |
324 | |
333 | |
325 | =item rcv $port, $callback->(@msg) |
334 | =item rcv $port, $callback->(@msg) |
326 | |
335 | |
327 | Replaces the callback on the specified miniport (after converting it to |
336 | Replaces the callback on the specified miniport (after converting it to |
… | |
… | |
332 | =item rcv $port, $smartmatch => $callback->(@msg), ... |
341 | =item rcv $port, $smartmatch => $callback->(@msg), ... |
333 | |
342 | |
334 | =item rcv $port, [$smartmatch...] => $callback->(@msg), ... |
343 | =item rcv $port, [$smartmatch...] => $callback->(@msg), ... |
335 | |
344 | |
336 | Register callbacks to be called on matching messages on the given full |
345 | Register callbacks to be called on matching messages on the given full |
337 | port (after converting it to one if required). |
346 | port (after converting it to one if required) and return the port. |
338 | |
347 | |
339 | The callback has to return a true value when its work is done, after |
348 | The callback has to return a true value when its work is done, after |
340 | which is will be removed, or a false value in which case it will stay |
349 | which is will be removed, or a false value in which case it will stay |
341 | registered. |
350 | registered. |
342 | |
351 | |
343 | The global C<$SELF> (exported by this module) contains C<$port> while |
352 | The global C<$SELF> (exported by this module) contains C<$port> while |
344 | executing the callback. |
353 | executing the callback. |
345 | |
354 | |
346 | Runtime errors wdurign callback execution will result in the port being |
355 | Runtime errors during callback execution will result in the port being |
347 | C<kil>ed. |
356 | C<kil>ed. |
348 | |
357 | |
349 | If the match is an array reference, then it will be matched against the |
358 | If the match is an array reference, then it will be matched against the |
350 | first elements of the message, otherwise only the first element is being |
359 | first elements of the message, otherwise only the first element is being |
351 | matched. |
360 | matched. |
… | |
… | |
354 | exported by this module) matches any single element of the message. |
363 | exported by this module) matches any single element of the message. |
355 | |
364 | |
356 | While not required, it is highly recommended that the first matching |
365 | While not required, it is highly recommended that the first matching |
357 | element is a string identifying the message. The one-string-only match is |
366 | element is a string identifying the message. The one-string-only match is |
358 | also the most efficient match (by far). |
367 | also the most efficient match (by far). |
|
|
368 | |
|
|
369 | Example: create a port and bind receivers on it in one go. |
|
|
370 | |
|
|
371 | my $port = rcv port, |
|
|
372 | msg1 => sub { ...; 0 }, |
|
|
373 | msg2 => sub { ...; 0 }, |
|
|
374 | ; |
|
|
375 | |
|
|
376 | Example: create a port, bind receivers and send it in a message elsewhere |
|
|
377 | in one go: |
|
|
378 | |
|
|
379 | snd $otherport, reply => |
|
|
380 | rcv port, |
|
|
381 | msg1 => sub { ...; 0 }, |
|
|
382 | ... |
|
|
383 | ; |
359 | |
384 | |
360 | =cut |
385 | =cut |
361 | |
386 | |
362 | sub rcv($@) { |
387 | sub rcv($@) { |
363 | my $port = shift; |
388 | my $port = shift; |
… | |
… | |
470 | } |
495 | } |
471 | } |
496 | } |
472 | |
497 | |
473 | =item $guard = mon $port, $cb->(@reason) |
498 | =item $guard = mon $port, $cb->(@reason) |
474 | |
499 | |
475 | =item $guard = mon $port, $otherport |
500 | =item $guard = mon $port, $rcvport |
476 | |
501 | |
|
|
502 | =item $guard = mon $port |
|
|
503 | |
477 | =item $guard = mon $port, $otherport, @msg |
504 | =item $guard = mon $port, $rcvport, @msg |
478 | |
505 | |
479 | Monitor the given port and do something when the port is killed. |
506 | Monitor the given port and do something when the port is killed, and |
|
|
507 | optionally return a guard that can be used to stop monitoring again. |
480 | |
508 | |
481 | In the first form, the callback is simply called with any number |
509 | In the first form (callback), the callback is simply called with any |
482 | of C<@reason> elements (no @reason means that the port was deleted |
510 | number of C<@reason> elements (no @reason means that the port was deleted |
483 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
511 | "normally"). Note also that I<< the callback B<must> never die >>, so use |
484 | C<eval> if unsure. |
512 | C<eval> if unsure. |
485 | |
513 | |
486 | In the second form, the other port will be C<kil>'ed with C<@reason>, iff |
514 | In the second form (another port given), the other port (C<$rcvport) |
487 | a @reason was specified, i.e. on "normal" kils nothing happens, while |
515 | will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on |
488 | under all other conditions, the other port is killed with the same reason. |
516 | "normal" kils nothing happens, while under all other conditions, the other |
|
|
517 | port is killed with the same reason. |
489 | |
518 | |
|
|
519 | The third form (kill self) is the same as the second form, except that |
|
|
520 | C<$rvport> defaults to C<$SELF>. |
|
|
521 | |
490 | In the last form, a message of the form C<@msg, @reason> will be C<snd>. |
522 | In the last form (message), a message of the form C<@msg, @reason> will be |
|
|
523 | C<snd>. |
|
|
524 | |
|
|
525 | As a rule of thumb, monitoring requests should always monitor a port from |
|
|
526 | a local port (or callback). The reason is that kill messages might get |
|
|
527 | lost, just like any other message. Another less obvious reason is that |
|
|
528 | even monitoring requests can get lost (for exmaple, when the connection |
|
|
529 | to the other node goes down permanently). When monitoring a port locally |
|
|
530 | these problems do not exist. |
491 | |
531 | |
492 | Example: call a given callback when C<$port> is killed. |
532 | Example: call a given callback when C<$port> is killed. |
493 | |
533 | |
494 | mon $port, sub { warn "port died because of <@_>\n" }; |
534 | mon $port, sub { warn "port died because of <@_>\n" }; |
495 | |
535 | |
496 | Example: kill ourselves when C<$port> is killed abnormally. |
536 | Example: kill ourselves when C<$port> is killed abnormally. |
497 | |
537 | |
498 | mon $port, $self; |
538 | mon $port; |
499 | |
539 | |
500 | Example: send us a restart message another C<$port> is killed. |
540 | Example: send us a restart message when another C<$port> is killed. |
501 | |
541 | |
502 | mon $port, $self => "restart"; |
542 | mon $port, $self => "restart"; |
503 | |
543 | |
504 | =cut |
544 | =cut |
505 | |
545 | |
506 | sub mon { |
546 | sub mon { |
507 | my ($noderef, $port) = split /#/, shift, 2; |
547 | my ($noderef, $port) = split /#/, shift, 2; |
508 | |
548 | |
509 | my $node = $NODE{$noderef} || add_node $noderef; |
549 | my $node = $NODE{$noderef} || add_node $noderef; |
510 | |
550 | |
511 | my $cb = shift; |
551 | my $cb = @_ ? shift : $SELF || Carp::croak 'mon: called with one argument only, but $SELF not set,'; |
512 | |
552 | |
513 | unless (ref $cb) { |
553 | unless (ref $cb) { |
514 | if (@_) { |
554 | if (@_) { |
515 | # send a kill info message |
555 | # send a kill info message |
516 | my (@msg) = ($cb, @_); |
556 | my (@msg) = ($cb, @_); |
… | |
… | |
547 | =cut |
587 | =cut |
548 | |
588 | |
549 | sub mon_guard { |
589 | sub mon_guard { |
550 | my ($port, @refs) = @_; |
590 | my ($port, @refs) = @_; |
551 | |
591 | |
|
|
592 | #TODO: mon-less form? |
|
|
593 | |
552 | mon $port, sub { 0 && @refs } |
594 | mon $port, sub { 0 && @refs } |
553 | } |
595 | } |
554 | |
596 | |
555 | =item lnk $port1, $port2 |
|
|
556 | |
|
|
557 | Link two ports. This is simply a shorthand for: |
|
|
558 | |
|
|
559 | mon $port1, $port2; |
|
|
560 | mon $port2, $port1; |
|
|
561 | |
|
|
562 | It means that if either one is killed abnormally, the other one gets |
|
|
563 | killed as well. |
|
|
564 | |
|
|
565 | =item kil $port[, @reason] |
597 | =item kil $port[, @reason] |
566 | |
598 | |
567 | Kill the specified port with the given C<@reason>. |
599 | Kill the specified port with the given C<@reason>. |
568 | |
600 | |
569 | If no C<@reason> is specified, then the port is killed "normally" (linked |
601 | If no C<@reason> is specified, then the port is killed "normally" (linked |
… | |
… | |
575 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
607 | Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks |
576 | will be reported as reason C<< die => $@ >>. |
608 | will be reported as reason C<< die => $@ >>. |
577 | |
609 | |
578 | Transport/communication errors are reported as C<< transport_error => |
610 | Transport/communication errors are reported as C<< transport_error => |
579 | $message >>. |
611 | $message >>. |
|
|
612 | |
|
|
613 | =cut |
|
|
614 | |
|
|
615 | =item $port = spawn $node, $initfunc[, @initdata] |
|
|
616 | |
|
|
617 | Creates a port on the node C<$node> (which can also be a port ID, in which |
|
|
618 | case it's the node where that port resides). |
|
|
619 | |
|
|
620 | The port ID of the newly created port is return immediately, and it is |
|
|
621 | permissible to immediately start sending messages or monitor the port. |
|
|
622 | |
|
|
623 | After the port has been created, the init function is |
|
|
624 | called. This function must be a fully-qualified function name |
|
|
625 | (e.g. C<MyApp::Chat::Server::init>). To specify a function in the main |
|
|
626 | program, use C<::name>. |
|
|
627 | |
|
|
628 | If the function doesn't exist, then the node tries to C<require> |
|
|
629 | the package, then the package above the package and so on (e.g. |
|
|
630 | C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function |
|
|
631 | exists or it runs out of package names. |
|
|
632 | |
|
|
633 | The init function is then called with the newly-created port as context |
|
|
634 | object (C<$SELF>) and the C<@initdata> values as arguments. |
|
|
635 | |
|
|
636 | A common idiom is to pass your own port, monitor the spawned port, and |
|
|
637 | in the init function, monitor the original port. This two-way monitoring |
|
|
638 | ensures that both ports get cleaned up when there is a problem. |
|
|
639 | |
|
|
640 | Example: spawn a chat server port on C<$othernode>. |
|
|
641 | |
|
|
642 | # this node, executed from within a port context: |
|
|
643 | my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF; |
|
|
644 | mon $server; |
|
|
645 | |
|
|
646 | # init function on C<$othernode> |
|
|
647 | sub connect { |
|
|
648 | my ($srcport) = @_; |
|
|
649 | |
|
|
650 | mon $srcport; |
|
|
651 | |
|
|
652 | rcv $SELF, sub { |
|
|
653 | ... |
|
|
654 | }; |
|
|
655 | } |
|
|
656 | |
|
|
657 | =cut |
|
|
658 | |
|
|
659 | sub _spawn { |
|
|
660 | my $port = shift; |
|
|
661 | my $init = shift; |
|
|
662 | |
|
|
663 | local $SELF = "$NODE#$port"; |
|
|
664 | eval { |
|
|
665 | &{ load_func $init } |
|
|
666 | }; |
|
|
667 | _self_die if $@; |
|
|
668 | } |
|
|
669 | |
|
|
670 | sub spawn(@) { |
|
|
671 | my ($noderef, undef) = split /#/, shift, 2; |
|
|
672 | |
|
|
673 | my $id = "$RUNIQ." . $ID++; |
|
|
674 | |
|
|
675 | $_[0] =~ /::/ |
|
|
676 | or Carp::croak "spawn init function must be a fully-qualified name, caught"; |
|
|
677 | |
|
|
678 | ($NODE{$noderef} || add_node $noderef) |
|
|
679 | ->send (["", "AnyEvent::MP::_spawn" => $id, @_]); |
|
|
680 | |
|
|
681 | "$noderef#$id" |
|
|
682 | } |
580 | |
683 | |
581 | =back |
684 | =back |
582 | |
685 | |
583 | =head1 NODE MESSAGES |
686 | =head1 NODE MESSAGES |
584 | |
687 | |
… | |
… | |
717 | or I<none>, there is no in-between, so monitoring single processes is |
820 | or I<none>, there is no in-between, so monitoring single processes is |
718 | difficult to implement. Monitoring in AEMP is more flexible than in |
821 | difficult to implement. Monitoring in AEMP is more flexible than in |
719 | Erlang, as one can choose between automatic kill, exit message or callback |
822 | Erlang, as one can choose between automatic kill, exit message or callback |
720 | on a per-process basis. |
823 | on a per-process basis. |
721 | |
824 | |
722 | =item * Erlang has different semantics for monitoring and linking, AEMP has the same. |
825 | =item * Erlang tries to hide remote/local connections, AEMP does not. |
723 | |
826 | |
724 | Monitoring in Erlang is not an indicator of process death/crashes, |
827 | Monitoring in Erlang is not an indicator of process death/crashes, |
725 | as linking is (except linking is unreliable in Erlang). In AEMP, the |
828 | as linking is (except linking is unreliable in Erlang). |
726 | semantics of monitoring and linking are identical, linking is simply |
829 | |
727 | two-way monitoring with automatic kill. |
830 | In AEMP, you don't "look up" registered port names or send to named ports |
|
|
831 | that might or might not be persistent. Instead, you normally spawn a port |
|
|
832 | on the remote node. The init function monitors the you, and you monitor |
|
|
833 | the remote port. Since both monitors are local to the node, they are much |
|
|
834 | more reliable. |
|
|
835 | |
|
|
836 | This also saves round-trips and avoids sending messages to the wrong port |
|
|
837 | (hard to do in Erlang). |
728 | |
838 | |
729 | =back |
839 | =back |
730 | |
840 | |
731 | =head1 SEE ALSO |
841 | =head1 SEE ALSO |
732 | |
842 | |