[ViewVC] Diff of: cvs/AnyEvent-MP/MP.pm

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.35 by root, Thu Aug 6 10:21:48 2009 UTC vs.
Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC

…		…
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
…		…
98		105
99	=cut	106	=cut
100		107
101	package AnyEvent::MP;	108	package AnyEvent::MP;
102		109
103	use AnyEvent::MP::Base;	110	use AnyEvent::MP::Kernel;
104		111
105	use common::sense;	112	use common::sense;
106		113
107	use Carp ();	114	use Carp ();
108		115
109	use AE ();	116	use AE ();
110		117
111	use base "Exporter";	118	use base "Exporter";
112		119
113	our $VERSION = '0.1';	120	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		121
114	our @EXPORT = qw(	122	our @EXPORT = qw(
115	NODE $NODE *SELF node_of _any_	123	NODE $NODE *SELF node_of _any_
116	resolve_node initialise_node	124	resolve_node initialise_node
117	snd rcv mon kil reg psub	125	snd rcv mon kil reg psub spawn
118	port	126	port
119	);	127	);
120		128
121	our $SELF;	129	our $SELF;
122		130
…		…
305	$port	313	$port
306	}	314	}
307		315
308	=item reg $port, $name	316	=item reg $port, $name
309		317
310	Registers the given port under the name C<$name>. If the name already	318	=item reg $name
311	exists it is replaced.	319
		320	Registers the given port (or C<$SELF><<< if missing) under the name
		321	C<$name>. If the name already exists it is replaced.
312		322
313	A port can only be registered under one well known name.	323	A port can only be registered under one well known name.
314		324
315	A port automatically becomes unregistered when it is killed.	325	A port automatically becomes unregistered when it is killed.
316		326
317	=cut	327	=cut
318		328
319	sub reg(@) {	329	sub reg(@) {
320	my ($port, $name) = @_;	330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
321		331
322	$REG{$name} = $port;	332	$REG{$_[0]} = $port;
323	}	333	}
324		334
325	=item rcv $port, $callback->(@msg)	335	=item rcv $port, $callback->(@msg)
326		336
327	Replaces the callback on the specified miniport (after converting it to	337	Replaces the callback on the specified miniport (after converting it to
…		…
332	=item rcv $port, $smartmatch => $callback->(@msg), ...	342	=item rcv $port, $smartmatch => $callback->(@msg), ...
333		343
334	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...	344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
335		345
336	Register callbacks to be called on matching messages on the given full	346	Register callbacks to be called on matching messages on the given full
337	port (after converting it to one if required).	347	port (after converting it to one if required) and return the port.
338		348
339	The callback has to return a true value when its work is done, after	349	The callback has to return a true value when its work is done, after
340	which is will be removed, or a false value in which case it will stay	350	which is will be removed, or a false value in which case it will stay
341	registered.	351	registered.
342		352
343	The global C<$SELF> (exported by this module) contains C<$port> while	353	The global C<$SELF> (exported by this module) contains C<$port> while
344	executing the callback.	354	executing the callback.
345		355
346	Runtime errors wdurign callback execution will result in the port being	356	Runtime errors during callback execution will result in the port being
347	C<kil>ed.	357	C<kil>ed.
348		358
349	If the match is an array reference, then it will be matched against the	359	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	360	first elements of the message, otherwise only the first element is being
351	matched.	361	matched.
…		…
354	exported by this module) matches any single element of the message.	364	exported by this module) matches any single element of the message.
355		365
356	While not required, it is highly recommended that the first matching	366	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	367	element is a string identifying the message. The one-string-only match is
358	also the most efficient match (by far).	368	also the most efficient match (by far).
		369
		370	Example: create a port and bind receivers on it in one go.
		371
		372	my $port = rcv port,
		373	msg1 => sub { ...; 0 },
		374	msg2 => sub { ...; 0 },
		375	;
		376
		377	Example: create a port, bind receivers and send it in a message elsewhere
		378	in one go:
		379
		380	snd $otherport, reply =>
		381	rcv port,
		382	msg1 => sub { ...; 0 },
		383	...
		384	;
359		385
360	=cut	386	=cut
361		387
362	sub rcv($@) {	388	sub rcv($@) {
363	my $port = shift;	389	my $port = shift;
…		…
470	}	496	}
471	}	497	}
472		498
473	=item $guard = mon $port, $cb->(@reason)	499	=item $guard = mon $port, $cb->(@reason)
474		500
475	=item $guard = mon $port, $otherport	501	=item $guard = mon $port, $rcvport
476		502
		503	=item $guard = mon $port
		504
477	=item $guard = mon $port, $otherport, @msg	505	=item $guard = mon $port, $rcvport, @msg
478		506
479	Monitor the given port and do something when the port is killed.	507	Monitor the given port and do something when the port is killed or
		508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
480		510
		511	C<mon> effectively guarantees that, in the absence of hardware failures,
		512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
		518
481	In the first form, the callback is simply called with any number	519	In the first form (callback), the callback is simply called with any
482	of C<@reason> elements (no @reason means that the port was deleted	520	number of C<@reason> elements (no @reason means that the port was deleted
483	"normally"). Note also that I<< the callback B<must> never die >>, so use	521	"normally"). Note also that I<< the callback B<must> never die >>, so use
484	C<eval> if unsure.	522	C<eval> if unsure.
485		523
486	In the second form, the other port will be C<kil>'ed with C<@reason>, iff	524	In the second form (another port given), the other port (C<$rcvport>)
487	a @reason was specified, i.e. on "normal" kils nothing happens, while	525	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.	526	"normal" kils nothing happens, while under all other conditions, the other
		527	port is killed with the same reason.
489		528
		529	The third form (kill self) is the same as the second form, except that
		530	C<$rvport> defaults to C<$SELF>.
		531
490	In the last form, a message of the form C<@msg, @reason> will be C<snd>.	532	In the last form (message), a message of the form C<@msg, @reason> will be
		533	C<snd>.
		534
		535	As a rule of thumb, monitoring requests should always monitor a port from
		536	a local port (or callback). The reason is that kill messages might get
		537	lost, just like any other message. Another less obvious reason is that
		538	even monitoring requests can get lost (for exmaple, when the connection
		539	to the other node goes down permanently). When monitoring a port locally
		540	these problems do not exist.
491		541
492	Example: call a given callback when C<$port> is killed.	542	Example: call a given callback when C<$port> is killed.
493		543
494	mon $port, sub { warn "port died because of <@_>\n" };	544	mon $port, sub { warn "port died because of <@_>\n" };
495		545
496	Example: kill ourselves when C<$port> is killed abnormally.	546	Example: kill ourselves when C<$port> is killed abnormally.
497		547
498	mon $port, $self;	548	mon $port;
499		549
500	Example: send us a restart message another C<$port> is killed.	550	Example: send us a restart message when another C<$port> is killed.
501		551
502	mon $port, $self => "restart";	552	mon $port, $self => "restart";
503		553
504	=cut	554	=cut
505		555
506	sub mon {	556	sub mon {
507	my ($noderef, $port) = split /#/, shift, 2;	557	my ($noderef, $port) = split /#/, shift, 2;
508		558
509	my $node = $NODE{$noderef} \|\| add_node $noderef;	559	my $node = $NODE{$noderef} \|\| add_node $noderef;
510		560
511	my $cb = shift;	561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
512		562
513	unless (ref $cb) {	563	unless (ref $cb) {
514	if (@_) {	564	if (@_) {
515	# send a kill info message	565	# send a kill info message
516	my (@msg) = ($cb, @_);	566	my (@msg) = ($cb, @_);
…		…
547	=cut	597	=cut
548		598
549	sub mon_guard {	599	sub mon_guard {
550	my ($port, @refs) = @_;	600	my ($port, @refs) = @_;
551		601
		602	#TODO: mon-less form?
		603
552	mon $port, sub { 0 && @refs }	604	mon $port, sub { 0 && @refs }
553	}	605	}
554		606
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]	607	=item kil $port[, @reason]
566		608
567	Kill the specified port with the given C<@reason>.	609	Kill the specified port with the given C<@reason>.
568		610
569	If no C<@reason> is specified, then the port is killed "normally" (linked	611	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	617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
576	will be reported as reason C<< die => $@ >>.	618	will be reported as reason C<< die => $@ >>.
577		619
578	Transport/communication errors are reported as C<< transport_error =>	620	Transport/communication errors are reported as C<< transport_error =>
579	$message >>.	621	$message >>.
		622
		623	=cut
		624
		625	=item $port = spawn $node, $initfunc[, @initdata]
		626
		627	Creates a port on the node C<$node> (which can also be a port ID, in which
		628	case it's the node where that port resides).
		629
		630	The port ID of the newly created port is return immediately, and it is
		631	permissible to immediately start sending messages or monitor the port.
		632
		633	After the port has been created, the init function is
		634	called. This function must be a fully-qualified function name
		635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		636	program, use C<::name>.
		637
		638	If the function doesn't exist, then the node tries to C<require>
		639	the package, then the package above the package and so on (e.g.
		640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		641	exists or it runs out of package names.
		642
		643	The init function is then called with the newly-created port as context
		644	object (C<$SELF>) and the C<@initdata> values as arguments.
		645
		646	A common idiom is to pass your own port, monitor the spawned port, and
		647	in the init function, monitor the original port. This two-way monitoring
		648	ensures that both ports get cleaned up when there is a problem.
		649
		650	Example: spawn a chat server port on C<$othernode>.
		651
		652	# this node, executed from within a port context:
		653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		654	mon $server;
		655
		656	# init function on C<$othernode>
		657	sub connect {
		658	my ($srcport) = @_;
		659
		660	mon $srcport;
		661
		662	rcv $SELF, sub {
		663	...
		664	};
		665	}
		666
		667	=cut
		668
		669	sub _spawn {
		670	my $port = shift;
		671	my $init = shift;
		672
		673	local $SELF = "$NODE#$port";
		674	eval {
		675	&{ load_func $init }
		676	};
		677	_self_die if $@;
		678	}
		679
		680	sub spawn(@) {
		681	my ($noderef, undef) = split /#/, shift, 2;
		682
		683	my $id = "$RUNIQ." . $ID++;
		684
		685	$_[0] =~ /::/
		686	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		687
		688	($NODE{$noderef} \|\| add_node $noderef)
		689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		690
		691	"$noderef#$id"
		692	}
580		693
581	=back	694	=back
582		695
583	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
584		697
…		…
717	or I<none>, there is no in-between, so monitoring single processes is	830	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	831	difficult to implement. Monitoring in AEMP is more flexible than in
719	Erlang, as one can choose between automatic kill, exit message or callback	832	Erlang, as one can choose between automatic kill, exit message or callback
720	on a per-process basis.	833	on a per-process basis.
721		834
722	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.	835	=item * Erlang tries to hide remote/local connections, AEMP does not.
723		836
724	Monitoring in Erlang is not an indicator of process death/crashes,	837	Monitoring in Erlang is not an indicator of process death/crashes,
725	as linking is (except linking is unreliable in Erlang). In AEMP, the	838	as linking is (except linking is unreliable in Erlang).
726	semantics of monitoring and linking are identical, linking is simply	839
727	two-way monitoring with automatic kill.	840	In AEMP, you don't "look up" registered port names or send to named ports
		841	that might or might not be persistent. Instead, you normally spawn a port
		842	on the remote node. The init function monitors the you, and you monitor
		843	the remote port. Since both monitors are local to the node, they are much
		844	more reliable.
		845
		846	This also saves round-trips and avoids sending messages to the wrong port
		847	(hard to do in Erlang).
728		848
729	=back	849	=back
730		850
731	=head1 SEE ALSO	851	=head1 SEE ALSO
732		852

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.35 by root, Thu Aug 6 10:21:48 2009 UTC vs. Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.35 by root, Thu Aug 6 10:21:48 2009 UTC vs.
Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC