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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs.
Revision 1.51 by root, Fri Aug 14 14:07:44 2009 UTC

…		…
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	13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node; # -OR-
		17	initialise_node "localhost:4040"; # -OR-
		18	initialise_node "slave/", "localhost:4040"
14		19
15	# ports are message endpoints	20	# ports are message endpoints
16		21
17	# sending messages	22	# sending messages
18	snd $port, type => data...;	23	snd $port, type => data...;
19	snd $port, @msg;	24	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	25	snd @msg_with_first_element_being_a_port;
21		26
22	# miniports	27	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	28	my $somple_port = port { my @msg = @_; 0 };
24		29
25	# full ports	30	# creating/using ports, type matching
26	my $port = port;	31	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	32	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	33	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		34
31	# remote ports	35	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	36	my $port = spawn $node, $initfunc, @initdata;
33
34	# more, smarter, matches (_any_ is exported by this module)
35	rcv $port, [child_died => $pid] => sub { ...
36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
37		37
38	# monitoring	38	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	39	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	40	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	41	mon $port, $otherport, @msg # send message on death
42		42
		43	=head1 CURRENT STATUS
		44
		45	AnyEvent::MP - stable API, should work
		46	AnyEvent::MP::Intro - outdated
		47	AnyEvent::MP::Kernel - WIP
		48	AnyEvent::MP::Transport - mostly stable
		49
		50	stay tuned.
		51
43	=head1 DESCRIPTION	52	=head1 DESCRIPTION
44		53
45	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
46		55
47	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
…		…
50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
51	manual page.	60	manual page.
52		61
53	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is severly broken and underdocumented,
54	so do not use. This was uploaded mainly to reserve the CPAN namespace -	63	so do not use. This was uploaded mainly to reserve the CPAN namespace -
55	stay tuned! The basic API should be finished, however.	64	stay tuned!
56		65
57	=head1 CONCEPTS	66	=head1 CONCEPTS
58		67
59	=over 4	68	=over 4
60		69
…		…
105		114
106	=cut	115	=cut
107		116
108	package AnyEvent::MP;	117	package AnyEvent::MP;
109		118
110	use AnyEvent::MP::Base;	119	use AnyEvent::MP::Kernel;
111		120
112	use common::sense;	121	use common::sense;
113		122
114	use Carp ();	123	use Carp ();
115		124
116	use AE ();	125	use AE ();
117		126
118	use base "Exporter";	127	use base "Exporter";
119		128
120	our $VERSION = $AnyEvent::MP::Base::VERSION;	129	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
121		130
122	our @EXPORT = qw(	131	our @EXPORT = qw(
123	NODE $NODE *SELF node_of _any_	132	NODE $NODE *SELF node_of _any_
124	resolve_node initialise_node	133	resolve_node initialise_node
125	snd rcv mon kil reg psub spawn	134	snd rcv mon kil reg psub spawn
…		…
154	it should know the noderefs of some other nodes in the network.	163	it should know the noderefs of some other nodes in the network.
155		164
156	This function initialises a node - it must be called exactly once (or	165	This function initialises a node - it must be called exactly once (or
157	never) before calling other AnyEvent::MP functions.	166	never) before calling other AnyEvent::MP functions.
158		167
159	All arguments are noderefs, which can be either resolved or unresolved.	168	All arguments (optionally except for the first) are noderefs, which can be
		169	either resolved or unresolved.
		170
		171	The first argument will be looked up in the configuration database first
		172	(if it is C<undef> then the current nodename will be used instead) to find
		173	the relevant configuration profile (see L<aemp>). If none is found then
		174	the default configuration is used. The configuration supplies additional
		175	seed/master nodes and can override the actual noderef.
160		176
161	There are two types of networked nodes, public nodes and slave nodes:	177	There are two types of networked nodes, public nodes and slave nodes:
162		178
163	=over 4	179	=over 4
164		180
165	=item public nodes	181	=item public nodes
166		182
167	For public nodes, C<$noderef> must either be a (possibly unresolved)	183	For public nodes, C<$noderef> (supplied either directly to
168	noderef, in which case it will be resolved, or C<undef> (or missing), in	184	C<initialise_node> or indirectly via a profile or the nodename) must be a
169	which case the noderef will be guessed.	185	noderef (possibly unresolved, in which case it will be resolved).
170		186
171	Afterwards, the node will bind itself on all endpoints and try to connect	187	After resolving, the node will bind itself on all endpoints and try to
172	to all additional C<$seednodes> that are specified. Seednodes are optional	188	connect to all additional C<$seednodes> that are specified. Seednodes are
173	and can be used to quickly bootstrap the node into an existing network.	189	optional and can be used to quickly bootstrap the node into an existing
		190	network.
174		191
175	=item slave nodes	192	=item slave nodes
176		193
177	When the C<$noderef> is the special string C<slave/>, then the node will	194	When the C<$noderef> (either as given or overriden by the config file)
		195	is the special string C<slave/>, then the node will become a slave
178	become a slave node. Slave nodes cannot be contacted from outside and will	196	node. Slave nodes cannot be contacted from outside and will route most of
179	route most of their traffic to the master node that they attach to.	197	their traffic to the master node that they attach to.
180		198
181	At least one additional noderef is required: The node will try to connect	199	At least one additional noderef is required (either by specifying it
182	to all of them and will become a slave attached to the first node it can	200	directly or because it is part of the configuration profile): The node
183	successfully connect to.	201	will try to connect to all of them and will become a slave attached to the
		202	first node it can successfully connect to.
184		203
185	=back	204	=back
186		205
187	This function will block until all nodes have been resolved and, for slave	206	This function will block until all nodes have been resolved and, for slave
188	nodes, until it has successfully established a connection to a master	207	nodes, until it has successfully established a connection to a master
189	server.	208	server.
190		209
191	Example: become a public node listening on the default node.	210	Example: become a public node listening on the guessed noderef, or the one
		211	specified via C<aemp> for the current node. This should be the most common
		212	form of invocation for "daemon"-type nodes.
192		213
193	initialise_node;	214	initialise_node;
		215
		216	Example: become a slave node to any of the the seednodes specified via
		217	C<aemp>. This form is often used for commandline clients.
		218
		219	initialise_node "slave/";
		220
		221	Example: become a slave node to any of the specified master servers. This
		222	form is also often used for commandline clients.
		223
		224	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
194		225
195	Example: become a public node, and try to contact some well-known master	226	Example: become a public node, and try to contact some well-known master
196	servers to become part of the network.	227	servers to become part of the network.
197		228
198	initialise_node undef, "master1", "master2";	229	initialise_node undef, "master1", "master2";
…		…
201		232
202	initialise_node 4041;	233	initialise_node 4041;
203		234
204	Example: become a public node, only visible on localhost port 4044.	235	Example: become a public node, only visible on localhost port 4044.
205		236
206	initialise_node "locahost:4044";	237	initialise_node "localhost:4044";
207
208	Example: become a slave node to any of the specified master servers.
209
210	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
211		238
212	=item $cv = resolve_node $noderef	239	=item $cv = resolve_node $noderef
213		240
214	Takes an unresolved node reference that may contain hostnames and	241	Takes an unresolved node reference that may contain hostnames and
215	abbreviated IDs, resolves all of them and returns a resolved node	242	abbreviated IDs, resolves all of them and returns a resolved node
…		…
271	that Storable can serialise and deserialise is allowed, and for the local	298	that Storable can serialise and deserialise is allowed, and for the local
272	node, anything can be passed.	299	node, anything can be passed.
273		300
274	=item $local_port = port	301	=item $local_port = port
275		302
276	Create a new local port object that can be used either as a pattern	303	Create a new local port object and returns its port ID. Initially it has
277	matching port ("full port") or a single-callback port ("miniport"),	304	no callbacks set and will throw an error when it receives messages.
278	depending on how C<rcv> callbacks are bound to the object.
279		305
280	=item $port = port { my @msg = @_; $finished }	306	=item $local_port = port { my @msg = @_ }
281		307
282	Creates a "miniport", that is, a very lightweight port without any pattern	308	Creates a new local port, and returns its ID. Semantically the same as
283	matching behind it, and returns its ID. Semantically the same as creating
284	a port and calling C<rcv $port, $callback> on it.	309	creating a port and calling C<rcv $port, $callback> on it.
285		310
286	The block will be called for every message received on the port. When the	311	The block will be called for every message received on the port, with the
287	callback returns a true value its job is considered "done" and the port	312	global variable C<$SELF> set to the port ID. Runtime errors will cause the
288	will be destroyed. Otherwise it will stay alive.	313	port to be C<kil>ed. The message will be passed as-is, no extra argument
		314	(i.e. no port ID) will be passed to the callback.
289		315
290	The message will be passed as-is, no extra argument (i.e. no port id) will	316	If you want to stop/destroy the port, simply C<kil> it:
291	be passed to the callback.
292		317
293	If you need the local port id in the callback, this works nicely:	318	my $port = port {
294		319	my @msg = @_;
295	my $port; $port = port {	320	...
296	snd $otherport, reply => $port;	321	kil $SELF;
297	};	322	};
298		323
299	=cut	324	=cut
300		325
301	sub rcv($@);	326	sub rcv($@);
		327
		328	sub _kilme {
		329	die "received message on port without callback";
		330	}
302		331
303	sub port(;&) {	332	sub port(;&) {
304	my $id = "$UNIQ." . $ID++;	333	my $id = "$UNIQ." . $ID++;
305	my $port = "$NODE#$id";	334	my $port = "$NODE#$id";
306		335
307	if (@_) {	336	rcv $port, shift \|\| \&_kilme;
308	rcv $port, shift;
309	} else {
310	$PORT{$id} = sub { }; # nop
311	}
312		337
313	$port	338	$port
314	}	339	}
315		340
316	=item reg $port, $name
317
318	=item reg $name
319
320	Registers the given port (or C<$SELF><<< if missing) under the name
321	C<$name>. If the name already exists it is replaced.
322
323	A port can only be registered under one well known name.
324
325	A port automatically becomes unregistered when it is killed.
326
327	=cut
328
329	sub reg(@) {
330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
331
332	$REG{$_[0]} = $port;
333	}
334
335	=item rcv $port, $callback->(@msg)	341	=item rcv $local_port, $callback->(@msg)
336		342
337	Replaces the callback on the specified miniport (after converting it to	343	Replaces the default callback on the specified port. There is no way to
338	one if required).	344	remove the default callback: use C<sub { }> to disable it, or better
339		345	C<kil> the port when it is no longer needed.
340	=item rcv $port, tagstring => $callback->(@msg), ...
341
342	=item rcv $port, $smartmatch => $callback->(@msg), ...
343
344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
345
346	Register callbacks to be called on matching messages on the given full
347	port (after converting it to one if required) and return the port.
348
349	The callback has to return a true value when its work is done, after
350	which is will be removed, or a false value in which case it will stay
351	registered.
352		346
353	The global C<$SELF> (exported by this module) contains C<$port> while	347	The global C<$SELF> (exported by this module) contains C<$port> while
354	executing the callback.	348	executing the callback. Runtime errors during callback execution will
		349	result in the port being C<kil>ed.
355		350
356	Runtime errors during callback execution will result in the port being	351	The default callback received all messages not matched by a more specific
357	C<kil>ed.	352	C<tag> match.
358		353
359	If the match is an array reference, then it will be matched against the	354	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
360	first elements of the message, otherwise only the first element is being
361	matched.
362		355
363	Any element in the match that is specified as C<_any_> (a function	356	Register callbacks to be called on messages starting with the given tag on
364	exported by this module) matches any single element of the message.	357	the given port (and return the port), or unregister it (when C<$callback>
		358	is C<$undef>).
365		359
366	While not required, it is highly recommended that the first matching	360	The original message will be passed to the callback, after the first
367	element is a string identifying the message. The one-string-only match is	361	element (the tag) has been removed. The callback will use the same
368	also the most efficient match (by far).	362	environment as the default callback (see above).
369		363
370	Example: create a port and bind receivers on it in one go.	364	Example: create a port and bind receivers on it in one go.
371		365
372	my $port = rcv port,	366	my $port = rcv port,
373	msg1 => sub { ...; 0 },	367	msg1 => sub { ... },
374	msg2 => sub { ...; 0 },	368	msg2 => sub { ... },
375	;	369	;
376		370
377	Example: create a port, bind receivers and send it in a message elsewhere	371	Example: create a port, bind receivers and send it in a message elsewhere
378	in one go:	372	in one go:
379		373
380	snd $otherport, reply =>	374	snd $otherport, reply =>
381	rcv port,	375	rcv port,
382	msg1 => sub { ...; 0 },	376	msg1 => sub { ... },
383	...	377	...
384	;	378	;
385		379
386	=cut	380	=cut
387		381
…		…
390	my ($noderef, $portid) = split /#/, $port, 2;	384	my ($noderef, $portid) = split /#/, $port, 2;
391		385
392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	386	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
393	or Carp::croak "$port: rcv can only be called on local ports, caught";	387	or Carp::croak "$port: rcv can only be called on local ports, caught";
394		388
395	if (@_ == 1) {	389	while (@_) {
		390	if (ref $_[0]) {
		391	if (my $self = $PORT_DATA{$portid}) {
		392	"AnyEvent::MP::Port" eq ref $self
		393	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		394
		395	$self->[2] = shift;
		396	} else {
396	my $cb = shift;	397	my $cb = shift;
397	delete $PORT_DATA{$portid};
398	$PORT{$portid} = sub {	398	$PORT{$portid} = sub {
399	local $SELF = $port;	399	local $SELF = $port;
400	eval {	400	eval { &$cb }; _self_die if $@;
401	&$cb	401	};
402	and kil $port;
403	};	402	}
404	_self_die if $@;	403	} elsif (defined $_[0]) {
405	};
406	} else {
407	my $self = $PORT_DATA{$portid} \|\|= do {	404	my $self = $PORT_DATA{$portid} \|\|= do {
408	my $self = bless {	405	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
409	id => $port,
410	}, "AnyEvent::MP::Port";
411		406
412	$PORT{$portid} = sub {	407	$PORT{$portid} = sub {
413	local $SELF = $port;	408	local $SELF = $port;
414		409
415	eval {
416	for (@{ $self->{rc0}{$_[0]} }) {	410	if (my $cb = $self->[1]{$_[0]}) {
417	$_ && &{$_->[0]}	411	shift;
418	&& undef $_;	412	eval { &$cb }; _self_die if $@;
419	}	413	} else {
420
421	for (@{ $self->{rcv}{$_[0]} }) {
422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
423	&& &{$_->[0]}	414	&{ $self->[0] };
424	&& undef $_;
425	}
426
427	for (@{ $self->{any} }) {
428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
429	&& &{$_->[0]}
430	&& undef $_;
431	}	415	}
432	};	416	};
433	_self_die if $@;	417
		418	$self
434	};	419	};
435		420
436	$self
437	};
438
439	"AnyEvent::MP::Port" eq ref $self	421	"AnyEvent::MP::Port" eq ref $self
440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	422	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
441		423
442	while (@_) {
443	my ($match, $cb) = splice @_, 0, 2;	424	my ($tag, $cb) = splice @_, 0, 2;
444		425
445	if (!ref $match) {	426	if (defined $cb) {
446	push @{ $self->{rc0}{$match} }, [$cb];	427	$self->[1]{$tag} = $cb;
447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
448	my ($type, @match) = @$match;
449	@match
450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
452	} else {	428	} else {
453	push @{ $self->{any} }, [$cb, $match];	429	delete $self->[1]{$tag};
454	}	430	}
455	}	431	}
456	}	432	}
457		433
458	$port	434	$port
…		…
762	convenience functionality.	738	convenience functionality.
763		739
764	This means that AEMP requires a less tightly controlled environment at the	740	This means that AEMP requires a less tightly controlled environment at the
765	cost of longer node references and a slightly higher management overhead.	741	cost of longer node references and a slightly higher management overhead.
766		742
		743	=item Erlang has a "remote ports are like local ports" philosophy, AEMP
		744	uses "local ports are like remote ports".
		745
		746	The failure modes for local ports are quite different (runtime errors
		747	only) then for remote ports - when a local port dies, you I<know> it dies,
		748	when a connection to another node dies, you know nothing about the other
		749	port.
		750
		751	Erlang pretends remote ports are as reliable as local ports, even when
		752	they are not.
		753
		754	AEMP encourages a "treat remote ports differently" philosophy, with local
		755	ports being the special case/exception, where transport errors cannot
		756	occur.
		757
767	=item * Erlang uses processes and a mailbox, AEMP does not queue.	758	=item * Erlang uses processes and a mailbox, AEMP does not queue.
768		759
769	Erlang uses processes that selctively receive messages, and therefore	760	Erlang uses processes that selectively receive messages, and therefore
770	needs a queue. AEMP is event based, queuing messages would serve no useful	761	needs a queue. AEMP is event based, queuing messages would serve no
771	purpose.	762	useful purpose. For the same reason the pattern-matching abilities of
		763	AnyEvent::MP are more limited, as there is little need to be able to
		764	filter messages without dequeing them.
772		765
773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	766	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
774		767
775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	768	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
776		769
777	Sending messages in Erlang is synchronous and blocks the process. AEMP	770	Sending messages in Erlang is synchronous and blocks the process (and
778	sends are immediate, connection establishment is handled in the	771	so does not need a queue that can overflow). AEMP sends are immediate,
779	background.	772	connection establishment is handled in the background.
780		773
781	=item * Erlang can silently lose messages, AEMP cannot.	774	=item * Erlang suffers from silent message loss, AEMP does not.
782		775
783	Erlang makes few guarantees on messages delivery - messages can get lost	776	Erlang makes few guarantees on messages delivery - messages can get lost
784	without any of the processes realising it (i.e. you send messages a, b,	777	without any of the processes realising it (i.e. you send messages a, b,
785	and c, and the other side only receives messages a and c).	778	and c, and the other side only receives messages a and c).
786		779
…		…
798	eventually be killed - it cannot happen that a node detects a port as dead	791	eventually be killed - it cannot happen that a node detects a port as dead
799	and then later sends messages to it, finding it is still alive.	792	and then later sends messages to it, finding it is still alive.
800		793
801	=item * Erlang can send messages to the wrong port, AEMP does not.	794	=item * Erlang can send messages to the wrong port, AEMP does not.
802		795
803	In Erlang it is quite possible that a node that restarts reuses a process	796	In Erlang it is quite likely that a node that restarts reuses a process ID
804	ID known to other nodes for a completely different process, causing	797	known to other nodes for a completely different process, causing messages
805	messages destined for that process to end up in an unrelated process.	798	destined for that process to end up in an unrelated process.
806		799
807	AEMP never reuses port IDs, so old messages or old port IDs floating	800	AEMP never reuses port IDs, so old messages or old port IDs floating
808	around in the network will not be sent to an unrelated port.	801	around in the network will not be sent to an unrelated port.
809		802
810	=item * Erlang uses unprotected connections, AEMP uses secure	803	=item * Erlang uses unprotected connections, AEMP uses secure
…		…
846	This also saves round-trips and avoids sending messages to the wrong port	839	This also saves round-trips and avoids sending messages to the wrong port
847	(hard to do in Erlang).	840	(hard to do in Erlang).
848		841
849	=back	842	=back
850		843
		844	=head1 RATIONALE
		845
		846	=over 4
		847
		848	=item Why strings for ports and noderefs, why not objects?
		849
		850	We considered "objects", but found that the actual number of methods
		851	thatc an be called are very low. Since port IDs and noderefs travel over
		852	the network frequently, the serialising/deserialising would add lots of
		853	overhead, as well as having to keep a proxy object.
		854
		855	Strings can easily be printed, easily serialised etc. and need no special
		856	procedures to be "valid".
		857
		858	And a a miniport consists of a single closure stored in a global hash - it
		859	can't become much cheaper.
		860
		861	=item Why favour JSON, why not real serialising format such as Storable?
		862
		863	In fact, any AnyEvent::MP node will happily accept Storable as framing
		864	format, but currently there is no way to make a node use Storable by
		865	default.
		866
		867	The default framing protocol is JSON because a) JSON::XS is many times
		868	faster for small messages and b) most importantly, after years of
		869	experience we found that object serialisation is causing more problems
		870	than it gains: Just like function calls, objects simply do not travel
		871	easily over the network, mostly because they will always be a copy, so you
		872	always have to re-think your design.
		873
		874	Keeping your messages simple, concentrating on data structures rather than
		875	objects, will keep your messages clean, tidy and efficient.
		876
		877	=back
		878
851	=head1 SEE ALSO	879	=head1 SEE ALSO
852		880
853	L<AnyEvent>.	881	L<AnyEvent>.
854		882
855	=head1 AUTHOR	883	=head1 AUTHOR

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs. Revision 1.51 by root, Fri Aug 14 14:07:44 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs.
Revision 1.51 by root, Fri Aug 14 14:07:44 2009 UTC