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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.58 by root, Sun Aug 16 02:55:16 2009 UTC

…		…
22	# sending messages	22	# sending messages
23	snd $port, type => data...;	23	snd $port, type => data...;
24	snd $port, @msg;	24	snd $port, @msg;
25	snd @msg_with_first_element_being_a_port;	25	snd @msg_with_first_element_being_a_port;
26		26
27	# creating/using miniports	27	# creating/using ports, the simple way
28	my $miniport = port { my @msg = @_; 0 };	28	my $simple_port = port { my @msg = @_; 0 };
29		29
30	# creating/using full ports	30	# creating/using ports, tagged message matching
31	my $port = port;	31	my $port = port;
32	rcv $port, smartmatch => $cb->(@msg);
33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	32	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
34	rcv $port, pong => sub { warn "pong received\n"; 0 };	33	rcv $port, pong => sub { warn "pong received\n"; 0 };
35
36	# more, smarter, matches (_any_ is exported by this module)
37	rcv $port, [child_died => $pid] => sub { ...
38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
39		34
40	# create a port on another node	35	# create a port on another node
41	my $port = spawn $node, $initfunc, @initdata;	36	my $port = spawn $node, $initfunc, @initdata;
42		37
43	# monitoring	38	# monitoring
…		…
74		69
75	=item port	70	=item port
76		71
77	A port is something you can send messages to (with the C<snd> function).	72	A port is something you can send messages to (with the C<snd> function).
78		73
79	Some ports allow you to register C<rcv> handlers that can match specific	74	Ports allow you to register C<rcv> handlers that can match all or just
80	messages. All C<rcv> handlers will receive messages they match, messages	75	some messages. Messages will not be queued.
81	will not be queued.
82		76
83	=item port id - C<noderef#portname>	77	=item port id - C<noderef#portname>
84		78
85	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	79	A port ID is the concatenation of a noderef, a hash-mark (C<#>) as
86	separator, and a port name (a printable string of unspecified format). An	80	separator, and a port name (a printable string of unspecified format). An
87	exception is the the node port, whose ID is identical to its node	81	exception is the the node port, whose ID is identical to its node
88	reference.	82	reference.
89		83
90	=item node	84	=item node
91		85
92	A node is a single process containing at least one port - the node	86	A node is a single process containing at least one port - the node port,
93	port. You can send messages to node ports to find existing ports or to	87	which provides nodes to manage each other remotely, and to create new
94	create new ports, among other things.	88	ports.
95		89
96	Nodes are either private (single-process only), slaves (connected to a	90	Nodes are either private (single-process only), slaves (connected to a
97	master node only) or public nodes (connectable from unrelated nodes).	91	master node only) or public nodes (connectable from unrelated nodes).
98		92
99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	93	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
…		…
148	kil $SELF, die => $msg;	142	kil $SELF, die => $msg;
149	}	143	}
150		144
151	=item $thisnode = NODE / $NODE	145	=item $thisnode = NODE / $NODE
152		146
153	The C<NODE> function returns, and the C<$NODE> variable contains	147	The C<NODE> function returns, and the C<$NODE> variable contains the
154	the noderef of the local node. The value is initialised by a call	148	noderef of the local node. The value is initialised by a call to
155	to C<become_public> or C<become_slave>, after which all local port	149	C<initialise_node>.
156	identifiers become invalid.
157		150
158	=item $noderef = node_of $port	151	=item $noderef = node_of $port
159		152
160	Extracts and returns the noderef from a portid or a noderef.	153	Extracts and returns the noderef from a port ID or a noderef.
161		154
162	=item initialise_node $noderef, $seednode, $seednode...	155	=item initialise_node $noderef, $seednode, $seednode...
163		156
164	=item initialise_node "slave/", $master, $master...	157	=item initialise_node "slave/", $master, $master...
165		158
…		…
204	At least one additional noderef is required (either by specifying it	197	At least one additional noderef is required (either by specifying it
205	directly or because it is part of the configuration profile): The node	198	directly or because it is part of the configuration profile): The node
206	will try to connect to all of them and will become a slave attached to the	199	will try to connect to all of them and will become a slave attached to the
207	first node it can successfully connect to.	200	first node it can successfully connect to.
208		201
		202	Note that slave nodes cannot change their name, and consequently, their
		203	master, so if the master goes down, the slave node will not function well
		204	anymore until it can re-establish conenciton to its master. This makes
		205	slave nodes unsuitable for long-term nodes or fault-tolerant networks.
		206
209	=back	207	=back
210		208
211	This function will block until all nodes have been resolved and, for slave	209	This function will block until all nodes have been resolved and, for slave
212	nodes, until it has successfully established a connection to a master	210	nodes, until it has successfully established a connection to a master
213	server.	211	server.
214		212
		213	All the seednodes will also be specially marked to automatically retry
		214	connecting to them infinitely.
		215
215	Example: become a public node listening on the guessed noderef, or the one	216	Example: become a public node listening on the guessed noderef, or the one
216	specified via C<aemp> for the current node. This should be the most common	217	specified via C<aemp> for the current node. This should be the most common
217	form of invocation for "daemon"-type nodes.	218	form of invocation for "daemon"-type nodes.
218		219
219	initialise_node;	220	initialise_node;
…		…
284	=item snd $port, type => @data	285	=item snd $port, type => @data
285		286
286	=item snd $port, @msg	287	=item snd $port, @msg
287		288
288	Send the given message to the given port ID, which can identify either	289	Send the given message to the given port ID, which can identify either
289	a local or a remote port, and can be either a string or soemthignt hat	290	a local or a remote port, and must be a port ID.
290	stringifies a sa port ID (such as a port object :).
291		291
292	While the message can be about anything, it is highly recommended to use a	292	While the message can be about anything, it is highly recommended to use a
293	string as first element (a portid, or some word that indicates a request	293	string as first element (a port ID, or some word that indicates a request
294	type etc.).	294	type etc.).
295		295
296	The message data effectively becomes read-only after a call to this	296	The message data effectively becomes read-only after a call to this
297	function: modifying any argument is not allowed and can cause many	297	function: modifying any argument is not allowed and can cause many
298	problems.	298	problems.
…		…
303	that Storable can serialise and deserialise is allowed, and for the local	303	that Storable can serialise and deserialise is allowed, and for the local
304	node, anything can be passed.	304	node, anything can be passed.
305		305
306	=item $local_port = port	306	=item $local_port = port
307		307
308	Create a new local port object that can be used either as a pattern	308	Create a new local port object and returns its port ID. Initially it has
309	matching port ("full port") or a single-callback port ("miniport"),	309	no callbacks set and will throw an error when it receives messages.
310	depending on how C<rcv> callbacks are bound to the object.
311		310
312	=item $port = port { my @msg = @_; $finished }	311	=item $local_port = port { my @msg = @_ }
313		312
314	Creates a "miniport", that is, a very lightweight port without any pattern	313	Creates a new local port, and returns its ID. Semantically the same as
315	matching behind it, and returns its ID. Semantically the same as creating
316	a port and calling C<rcv $port, $callback> on it.	314	creating a port and calling C<rcv $port, $callback> on it.
317		315
318	The block will be called for every message received on the port. When the	316	The block will be called for every message received on the port, with the
319	callback returns a true value its job is considered "done" and the port	317	global variable C<$SELF> set to the port ID. Runtime errors will cause the
320	will be destroyed. Otherwise it will stay alive.	318	port to be C<kil>ed. The message will be passed as-is, no extra argument
		319	(i.e. no port ID) will be passed to the callback.
321		320
322	The message will be passed as-is, no extra argument (i.e. no port id) will	321	If you want to stop/destroy the port, simply C<kil> it:
323	be passed to the callback.
324		322
325	If you need the local port id in the callback, this works nicely:	323	my $port = port {
326		324	my @msg = @_;
327	my $port; $port = port {	325	...
328	snd $otherport, reply => $port;	326	kil $SELF;
329	};	327	};
330		328
331	=cut	329	=cut
332		330
333	sub rcv($@);	331	sub rcv($@);
		332
		333	sub _kilme {
		334	die "received message on port without callback";
		335	}
334		336
335	sub port(;&) {	337	sub port(;&) {
336	my $id = "$UNIQ." . $ID++;	338	my $id = "$UNIQ." . $ID++;
337	my $port = "$NODE#$id";	339	my $port = "$NODE#$id";
338		340
339	if (@_) {	341	rcv $port, shift \|\| \&_kilme;
340	rcv $port, shift;
341	} else {
342	$PORT{$id} = sub { }; # nop
343	}
344		342
345	$port	343	$port
346	}	344	}
347		345
348	=item reg $port, $name
349
350	=item reg $name
351
352	Registers the given port (or C<$SELF><<< if missing) under the name
353	C<$name>. If the name already exists it is replaced.
354
355	A port can only be registered under one well known name.
356
357	A port automatically becomes unregistered when it is killed.
358
359	=cut
360
361	sub reg(@) {
362	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
363
364	$REG{$_[0]} = $port;
365	}
366
367	=item rcv $port, $callback->(@msg)	346	=item rcv $local_port, $callback->(@msg)
368		347
369	Replaces the callback on the specified miniport (after converting it to	348	Replaces the default callback on the specified port. There is no way to
370	one if required).	349	remove the default callback: use C<sub { }> to disable it, or better
371		350	C<kil> the port when it is no longer needed.
372	=item rcv $port, tagstring => $callback->(@msg), ...
373
374	=item rcv $port, $smartmatch => $callback->(@msg), ...
375
376	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
377
378	Register callbacks to be called on matching messages on the given full
379	port (after converting it to one if required) and return the port.
380
381	The callback has to return a true value when its work is done, after
382	which is will be removed, or a false value in which case it will stay
383	registered.
384		351
385	The global C<$SELF> (exported by this module) contains C<$port> while	352	The global C<$SELF> (exported by this module) contains C<$port> while
386	executing the callback.	353	executing the callback. Runtime errors during callback execution will
		354	result in the port being C<kil>ed.
387		355
388	Runtime errors during callback execution will result in the port being	356	The default callback received all messages not matched by a more specific
389	C<kil>ed.	357	C<tag> match.
390		358
391	If the match is an array reference, then it will be matched against the	359	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
392	first elements of the message, otherwise only the first element is being
393	matched.
394		360
395	Any element in the match that is specified as C<_any_> (a function	361	Register (or replace) callbacks to be called on messages starting with the
396	exported by this module) matches any single element of the message.	362	given tag on the given port (and return the port), or unregister it (when
		363	C<$callback> is C<$undef> or missing). There can only be one callback
		364	registered for each tag.
397		365
398	While not required, it is highly recommended that the first matching	366	The original message will be passed to the callback, after the first
399	element is a string identifying the message. The one-string-only match is	367	element (the tag) has been removed. The callback will use the same
400	also the most efficient match (by far).	368	environment as the default callback (see above).
401		369
402	Example: create a port and bind receivers on it in one go.	370	Example: create a port and bind receivers on it in one go.
403		371
404	my $port = rcv port,	372	my $port = rcv port,
405	msg1 => sub { ...; 0 },	373	msg1 => sub { ... },
406	msg2 => sub { ...; 0 },	374	msg2 => sub { ... },
407	;	375	;
408		376
409	Example: create a port, bind receivers and send it in a message elsewhere	377	Example: create a port, bind receivers and send it in a message elsewhere
410	in one go:	378	in one go:
411		379
412	snd $otherport, reply =>	380	snd $otherport, reply =>
413	rcv port,	381	rcv port,
414	msg1 => sub { ...; 0 },	382	msg1 => sub { ... },
415	...	383	...
416	;	384	;
		385
		386	Example: temporarily register a rcv callback for a tag matching some port
		387	(e.g. for a rpc reply) and unregister it after a message was received.
		388
		389	rcv $port, $otherport => sub {
		390	my @reply = @_;
		391
		392	rcv $SELF, $otherport;
		393	};
417		394
418	=cut	395	=cut
419		396
420	sub rcv($@) {	397	sub rcv($@) {
421	my $port = shift;	398	my $port = shift;
422	my ($noderef, $portid) = split /#/, $port, 2;	399	my ($noderef, $portid) = split /#/, $port, 2;
423		400
424	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	401	$NODE{$noderef} == $NODE{""}
425	or Carp::croak "$port: rcv can only be called on local ports, caught";	402	or Carp::croak "$port: rcv can only be called on local ports, caught";
426		403
427	if (@_ == 1) {	404	while (@_) {
		405	if (ref $_[0]) {
		406	if (my $self = $PORT_DATA{$portid}) {
		407	"AnyEvent::MP::Port" eq ref $self
		408	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		409
		410	$self->[2] = shift;
		411	} else {
428	my $cb = shift;	412	my $cb = shift;
429	delete $PORT_DATA{$portid};
430	$PORT{$portid} = sub {	413	$PORT{$portid} = sub {
431	local $SELF = $port;	414	local $SELF = $port;
432	eval {	415	eval { &$cb }; _self_die if $@;
433	&$cb	416	};
434	and kil $port;
435	};	417	}
436	_self_die if $@;	418	} elsif (defined $_[0]) {
437	};
438	} else {
439	my $self = $PORT_DATA{$portid} \|\|= do {	419	my $self = $PORT_DATA{$portid} \|\|= do {
440	my $self = bless {	420	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
441	id => $port,
442	}, "AnyEvent::MP::Port";
443		421
444	$PORT{$portid} = sub {	422	$PORT{$portid} = sub {
445	local $SELF = $port;	423	local $SELF = $port;
446		424
447	eval {
448	for (@{ $self->{rc0}{$_[0]} }) {	425	if (my $cb = $self->[1]{$_[0]}) {
449	$_ && &{$_->[0]}	426	shift;
450	&& undef $_;	427	eval { &$cb }; _self_die if $@;
451	}	428	} else {
452
453	for (@{ $self->{rcv}{$_[0]} }) {
454	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
455	&& &{$_->[0]}	429	&{ $self->[0] };
456	&& undef $_;
457	}
458
459	for (@{ $self->{any} }) {
460	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
461	&& &{$_->[0]}
462	&& undef $_;
463	}	430	}
464	};	431	};
465	_self_die if $@;	432
		433	$self
466	};	434	};
467		435
468	$self
469	};
470
471	"AnyEvent::MP::Port" eq ref $self	436	"AnyEvent::MP::Port" eq ref $self
472	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	437	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
473		438
474	while (@_) {
475	my ($match, $cb) = splice @_, 0, 2;	439	my ($tag, $cb) = splice @_, 0, 2;
476		440
477	if (!ref $match) {	441	if (defined $cb) {
478	push @{ $self->{rc0}{$match} }, [$cb];	442	$self->[1]{$tag} = $cb;
479	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
480	my ($type, @match) = @$match;
481	@match
482	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
483	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
484	} else {	443	} else {
485	push @{ $self->{any} }, [$cb, $match];	444	delete $self->[1]{$tag};
486	}	445	}
487	}	446	}
488	}	447	}
489		448
490	$port	449	$port
…		…
546	message loss has been detected. No messages will be lost "in between"	505	message loss has been detected. No messages will be lost "in between"
547	(after the first lost message no further messages will be received by the	506	(after the first lost message no further messages will be received by the
548	port). After the monitoring action was invoked, further messages might get	507	port). After the monitoring action was invoked, further messages might get
549	delivered again.	508	delivered again.
550		509
		510	Note that monitoring-actions are one-shot: once released, they are removed
		511	and will not trigger again.
		512
551	In the first form (callback), the callback is simply called with any	513	In the first form (callback), the callback is simply called with any
552	number of C<@reason> elements (no @reason means that the port was deleted	514	number of C<@reason> elements (no @reason means that the port was deleted
553	"normally"). Note also that I<< the callback B<must> never die >>, so use	515	"normally"). Note also that I<< the callback B<must> never die >>, so use
554	C<eval> if unsure.	516	C<eval> if unsure.
555		517
…		…
715	my $id = "$RUNIQ." . $ID++;	677	my $id = "$RUNIQ." . $ID++;
716		678
717	$_[0] =~ /::/	679	$_[0] =~ /::/
718	or Carp::croak "spawn init function must be a fully-qualified name, caught";	680	or Carp::croak "spawn init function must be a fully-qualified name, caught";
719		681
720	($NODE{$noderef} \|\| add_node $noderef)	682	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
721	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
722		683
723	"$noderef#$id"	684	"$noderef#$id"
724	}	685	}
725
726	=back
727
728	=head1 NODE MESSAGES
729
730	Nodes understand the following messages sent to them. Many of them take
731	arguments called C<@reply>, which will simply be used to compose a reply
732	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
733	the remaining arguments are simply the message data.
734
735	While other messages exist, they are not public and subject to change.
736
737	=over 4
738
739	=cut
740
741	=item lookup => $name, @reply
742
743	Replies with the port ID of the specified well-known port, or C<undef>.
744
745	=item devnull => ...
746
747	Generic data sink/CPU heat conversion.
748
749	=item relay => $port, @msg
750
751	Simply forwards the message to the given port.
752
753	=item eval => $string[ @reply]
754
755	Evaluates the given string. If C<@reply> is given, then a message of the
756	form C<@reply, $@, @evalres> is sent.
757
758	Example: crash another node.
759
760	snd $othernode, eval => "exit";
761
762	=item time => @reply
763
764	Replies the the current node time to C<@reply>.
765
766	Example: tell the current node to send the current time to C<$myport> in a
767	C<timereply> message.
768
769	snd $NODE, time => $myport, timereply => 1, 2;
770	# => snd $myport, timereply => 1, 2, <time>
771		686
772	=back	687	=back
773		688
774	=head1 AnyEvent::MP vs. Distributed Erlang	689	=head1 AnyEvent::MP vs. Distributed Erlang
775		690
…		…
794	convenience functionality.	709	convenience functionality.
795		710
796	This means that AEMP requires a less tightly controlled environment at the	711	This means that AEMP requires a less tightly controlled environment at the
797	cost of longer node references and a slightly higher management overhead.	712	cost of longer node references and a slightly higher management overhead.
798		713
		714	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
		715	uses "local ports are like remote ports".
		716
		717	The failure modes for local ports are quite different (runtime errors
		718	only) then for remote ports - when a local port dies, you I<know> it dies,
		719	when a connection to another node dies, you know nothing about the other
		720	port.
		721
		722	Erlang pretends remote ports are as reliable as local ports, even when
		723	they are not.
		724
		725	AEMP encourages a "treat remote ports differently" philosophy, with local
		726	ports being the special case/exception, where transport errors cannot
		727	occur.
		728
799	=item * Erlang uses processes and a mailbox, AEMP does not queue.	729	=item * Erlang uses processes and a mailbox, AEMP does not queue.
800		730
801	Erlang uses processes that selctively receive messages, and therefore	731	Erlang uses processes that selectively receive messages, and therefore
802	needs a queue. AEMP is event based, queuing messages would serve no useful	732	needs a queue. AEMP is event based, queuing messages would serve no
803	purpose.	733	useful purpose. For the same reason the pattern-matching abilities of
		734	AnyEvent::MP are more limited, as there is little need to be able to
		735	filter messages without dequeing them.
804		736
805	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	737	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
806		738
807	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
808		740
809	Sending messages in Erlang is synchronous and blocks the process. AEMP	741	Sending messages in Erlang is synchronous and blocks the process (and
810	sends are immediate, connection establishment is handled in the	742	so does not need a queue that can overflow). AEMP sends are immediate,
811	background.	743	connection establishment is handled in the background.
812		744
813	=item * Erlang can silently lose messages, AEMP cannot.	745	=item * Erlang suffers from silent message loss, AEMP does not.
814		746
815	Erlang makes few guarantees on messages delivery - messages can get lost	747	Erlang makes few guarantees on messages delivery - messages can get lost
816	without any of the processes realising it (i.e. you send messages a, b,	748	without any of the processes realising it (i.e. you send messages a, b,
817	and c, and the other side only receives messages a and c).	749	and c, and the other side only receives messages a and c).
818		750
…		…
830	eventually be killed - it cannot happen that a node detects a port as dead	762	eventually be killed - it cannot happen that a node detects a port as dead
831	and then later sends messages to it, finding it is still alive.	763	and then later sends messages to it, finding it is still alive.
832		764
833	=item * Erlang can send messages to the wrong port, AEMP does not.	765	=item * Erlang can send messages to the wrong port, AEMP does not.
834		766
835	In Erlang it is quite possible that a node that restarts reuses a process	767	In Erlang it is quite likely that a node that restarts reuses a process ID
836	ID known to other nodes for a completely different process, causing	768	known to other nodes for a completely different process, causing messages
837	messages destined for that process to end up in an unrelated process.	769	destined for that process to end up in an unrelated process.
838		770
839	AEMP never reuses port IDs, so old messages or old port IDs floating	771	AEMP never reuses port IDs, so old messages or old port IDs floating
840	around in the network will not be sent to an unrelated port.	772	around in the network will not be sent to an unrelated port.
841		773
842	=item * Erlang uses unprotected connections, AEMP uses secure	774	=item * Erlang uses unprotected connections, AEMP uses secure

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs. Revision 1.58 by root, Sun Aug 16 02:55:16 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.58 by root, Sun Aug 16 02:55:16 2009 UTC