[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 1.42 by root, Sun Aug 9 00:41:49 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
…		…
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, $rcvport, @msg
478		505
479	Monitor the given port and do something when the port is killed.	506	Monitor the given port and do something when the port is killed or
		507	messages to it were lost, and optionally return a guard that can be used
		508	to stop monitoring again.
480		509
		510	C<mon> effectively guarantees that, in the absence of hardware failures,
		511	that after starting the monitor, either all messages sent to the port
		512	will arrive, or the monitoring action will be invoked after possible
		513	message loss has been detected. No messages will be lost "in between"
		514	(after the first lost message no further messages will be received by the
		515	port). After the monitoring action was invoked, further messages might get
		516	delivered again.
		517
481	In the first form, the callback is simply called with any number	518	In the first form (callback), the callback is simply called with any
482	of C<@reason> elements (no @reason means that the port was deleted	519	number of C<@reason> elements (no @reason means that the port was deleted
483	"normally"). Note also that I<< the callback B<must> never die >>, so use	520	"normally"). Note also that I<< the callback B<must> never die >>, so use
484	C<eval> if unsure.	521	C<eval> if unsure.
485		522
486	In the second form, the other port will be C<kil>'ed with C<@reason>, iff	523	In the second form (another port given), the other port (C<$rcvport)
487	a @reason was specified, i.e. on "normal" kils nothing happens, while	524	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.	525	"normal" kils nothing happens, while under all other conditions, the other
		526	port is killed with the same reason.
489		527
		528	The third form (kill self) is the same as the second form, except that
		529	C<$rvport> defaults to C<$SELF>.
		530
490	In the last form, a message of the form C<@msg, @reason> will be C<snd>.	531	In the last form (message), a message of the form C<@msg, @reason> will be
		532	C<snd>.
		533
		534	As a rule of thumb, monitoring requests should always monitor a port from
		535	a local port (or callback). The reason is that kill messages might get
		536	lost, just like any other message. Another less obvious reason is that
		537	even monitoring requests can get lost (for exmaple, when the connection
		538	to the other node goes down permanently). When monitoring a port locally
		539	these problems do not exist.
491		540
492	Example: call a given callback when C<$port> is killed.	541	Example: call a given callback when C<$port> is killed.
493		542
494	mon $port, sub { warn "port died because of <@_>\n" };	543	mon $port, sub { warn "port died because of <@_>\n" };
495		544
496	Example: kill ourselves when C<$port> is killed abnormally.	545	Example: kill ourselves when C<$port> is killed abnormally.
497		546
498	mon $port, $self;	547	mon $port;
499		548
500	Example: send us a restart message another C<$port> is killed.	549	Example: send us a restart message when another C<$port> is killed.
501		550
502	mon $port, $self => "restart";	551	mon $port, $self => "restart";
503		552
504	=cut	553	=cut
505		554
506	sub mon {	555	sub mon {
507	my ($noderef, $port) = split /#/, shift, 2;	556	my ($noderef, $port) = split /#/, shift, 2;
508		557
509	my $node = $NODE{$noderef} \|\| add_node $noderef;	558	my $node = $NODE{$noderef} \|\| add_node $noderef;
510		559
511	my $cb = shift;	560	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
512		561
513	unless (ref $cb) {	562	unless (ref $cb) {
514	if (@_) {	563	if (@_) {
515	# send a kill info message	564	# send a kill info message
516	my (@msg) = ($cb, @_);	565	my (@msg) = ($cb, @_);
…		…
547	=cut	596	=cut
548		597
549	sub mon_guard {	598	sub mon_guard {
550	my ($port, @refs) = @_;	599	my ($port, @refs) = @_;
551		600
		601	#TODO: mon-less form?
		602
552	mon $port, sub { 0 && @refs }	603	mon $port, sub { 0 && @refs }
553	}	604	}
554		605
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]	606	=item kil $port[, @reason]
566		607
567	Kill the specified port with the given C<@reason>.	608	Kill the specified port with the given C<@reason>.
568		609
569	If no C<@reason> is specified, then the port is killed "normally" (linked	610	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	616	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
576	will be reported as reason C<< die => $@ >>.	617	will be reported as reason C<< die => $@ >>.
577		618
578	Transport/communication errors are reported as C<< transport_error =>	619	Transport/communication errors are reported as C<< transport_error =>
579	$message >>.	620	$message >>.
		621
		622	=cut
		623
		624	=item $port = spawn $node, $initfunc[, @initdata]
		625
		626	Creates a port on the node C<$node> (which can also be a port ID, in which
		627	case it's the node where that port resides).
		628
		629	The port ID of the newly created port is return immediately, and it is
		630	permissible to immediately start sending messages or monitor the port.
		631
		632	After the port has been created, the init function is
		633	called. This function must be a fully-qualified function name
		634	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		635	program, use C<::name>.
		636
		637	If the function doesn't exist, then the node tries to C<require>
		638	the package, then the package above the package and so on (e.g.
		639	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		640	exists or it runs out of package names.
		641
		642	The init function is then called with the newly-created port as context
		643	object (C<$SELF>) and the C<@initdata> values as arguments.
		644
		645	A common idiom is to pass your own port, monitor the spawned port, and
		646	in the init function, monitor the original port. This two-way monitoring
		647	ensures that both ports get cleaned up when there is a problem.
		648
		649	Example: spawn a chat server port on C<$othernode>.
		650
		651	# this node, executed from within a port context:
		652	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		653	mon $server;
		654
		655	# init function on C<$othernode>
		656	sub connect {
		657	my ($srcport) = @_;
		658
		659	mon $srcport;
		660
		661	rcv $SELF, sub {
		662	...
		663	};
		664	}
		665
		666	=cut
		667
		668	sub _spawn {
		669	my $port = shift;
		670	my $init = shift;
		671
		672	local $SELF = "$NODE#$port";
		673	eval {
		674	&{ load_func $init }
		675	};
		676	_self_die if $@;
		677	}
		678
		679	sub spawn(@) {
		680	my ($noderef, undef) = split /#/, shift, 2;
		681
		682	my $id = "$RUNIQ." . $ID++;
		683
		684	$_[0] =~ /::/
		685	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		686
		687	($NODE{$noderef} \|\| add_node $noderef)
		688	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		689
		690	"$noderef#$id"
		691	}
580		692
581	=back	693	=back
582		694
583	=head1 NODE MESSAGES	695	=head1 NODE MESSAGES
584		696
…		…
717	or I<none>, there is no in-between, so monitoring single processes is	829	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	830	difficult to implement. Monitoring in AEMP is more flexible than in
719	Erlang, as one can choose between automatic kill, exit message or callback	831	Erlang, as one can choose between automatic kill, exit message or callback
720	on a per-process basis.	832	on a per-process basis.
721		833
722	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.	834	=item * Erlang tries to hide remote/local connections, AEMP does not.
723		835
724	Monitoring in Erlang is not an indicator of process death/crashes,	836	Monitoring in Erlang is not an indicator of process death/crashes,
725	as linking is (except linking is unreliable in Erlang). In AEMP, the	837	as linking is (except linking is unreliable in Erlang).
726	semantics of monitoring and linking are identical, linking is simply	838
727	two-way monitoring with automatic kill.	839	In AEMP, you don't "look up" registered port names or send to named ports
		840	that might or might not be persistent. Instead, you normally spawn a port
		841	on the remote node. The init function monitors the you, and you monitor
		842	the remote port. Since both monitors are local to the node, they are much
		843	more reliable.
		844
		845	This also saves round-trips and avoids sending messages to the wrong port
		846	(hard to do in Erlang).
728		847
729	=back	848	=back
730		849
731	=head1 SEE ALSO	850	=head1 SEE ALSO
732		851

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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 1.42 by root, Sun Aug 9 00:41:49 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 1.42 by root, Sun Aug 9 00:41:49 2009 UTC