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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs.
Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC

…		…
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		14
15	# initialise the node so it can send/receive messages	15	# initialise the node so it can send/receive messages
16	initialise_node; # -OR-	16	initialise_node;
17	initialise_node "localhost:4040"; # -OR-
18	initialise_node "slave/", "localhost:4040"
19		17
20	# ports are message endpoints	18	# ports are message endpoints
21		19
22	# sending messages	20	# sending messages
23	snd $port, type => data...;	21	snd $port, type => data...;
24	snd $port, @msg;	22	snd $port, @msg;
25	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
26		24
27	# creating/using miniports	25	# creating/using ports, the simple way
28	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
29		27
30	# creating/using full ports	28	# creating/using ports, tagged message matching
31	my $port = port;	29	my $port = port;
32	rcv $port, smartmatch => $cb->(@msg);
33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
34	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	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		32
40	# create a port on another node	33	# create a port on another node
41	my $port = spawn $node, $initfunc, @initdata;	34	my $port = spawn $node, $initfunc, @initdata;
42		35
43	# monitoring	36	# monitoring
…		…
47		40
48	=head1 CURRENT STATUS	41	=head1 CURRENT STATUS
49		42
50	AnyEvent::MP - stable API, should work	43	AnyEvent::MP - stable API, should work
51	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - outdated
52	AnyEvent::MP::Kernel - WIP
53	AnyEvent::MP::Transport - mostly stable	45	AnyEvent::MP::Kernel - mostly stable
		46	AnyEvent::MP::Global - mostly stable
		47	AnyEvent::MP::Node - mostly stable, but internal anyways
		48	AnyEvent::MP::Transport - mostly stable, but internal anyways
54		49
55	stay tuned.	50	stay tuned.
56		51
57	=head1 DESCRIPTION	52	=head1 DESCRIPTION
58		53
59	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
60		55
61	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
62	on the same or other hosts.	57	on the same or other hosts, and you can supervise entities remotely.
63		58
64	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>
65	manual page.	60	manual page and the examples under F<eg/>.
66		61
67	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is a bit underdocumented.
68	so do not use. This was uploaded mainly to reserve the CPAN namespace -
69	stay tuned!
70		63
71	=head1 CONCEPTS	64	=head1 CONCEPTS
72		65
73	=over 4	66	=over 4
74		67
75	=item port	68	=item port
76		69
77	A port is something you can send messages to (with the C<snd> function).	70	A port is something you can send messages to (with the C<snd> function).
78		71
79	Some ports allow you to register C<rcv> handlers that can match specific	72	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	73	some messages. Messages send to ports will not be queued, regardless of
81	will not be queued.	74	anything was listening for them or not.
82		75
83	=item port id - C<noderef#portname>	76	=item port ID - C<nodeid#portname>
84		77
85	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	78	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
86	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format).
87	exception is the the node port, whose ID is identical to its node
88	reference.
89		80
90	=item node	81	=item node
91		82
92	A node is a single process containing at least one port - the node	83	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	84	which enables nodes to manage each other remotely, and to create new
94	create new ports, among other things.	85	ports.
95		86
96	Nodes are either private (single-process only), slaves (connected to a	87	Nodes are either public (have one or more listening ports) or private
97	master node only) or public nodes (connectable from unrelated nodes).	88	(no listening ports). Private nodes cannot talk to other private nodes
		89	currently.
98		90
99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	91	=item node ID - C<[a-za-Z0-9_\-.:]+>
100		92
101	A node reference is a string that either simply identifies the node (for	93	A node ID is a string that uniquely identifies the node within a
102	private and slave nodes), or contains a recipe on how to reach a given	94	network. Depending on the configuration used, node IDs can look like a
103	node (for public nodes).	95	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		96	doesn't interpret node IDs in any way.
104		97
105	This recipe is simply a comma-separated list of C<address:port> pairs (for	98	=item binds - C<ip:port>
106	TCP/IP, other protocols might look different).
107		99
108	Node references come in two flavours: resolved (containing only numerical	100	Nodes can only talk to each other by creating some kind of connection to
109	addresses) or unresolved (where hostnames are used instead of addresses).	101	each other. To do this, nodes should listen on one or more local transport
		102	endpoints - binds. Currently, only standard C<ip:port> specifications can
		103	be used, which specify TCP ports to listen on.
110		104
111	Before using an unresolved node reference in a message you first have to	105	=item seeds - C<host:port>
112	resolve it.	106
		107	When a node starts, it knows nothing about the network. To teach the node
		108	about the network it first has to contact some other node within the
		109	network. This node is called a seed.
		110
		111	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		112	are expected to be long-running, and at least one of those should always
		113	be available. When nodes run out of connections (e.g. due to a network
		114	error), they try to re-establish connections to some seednodes again to
		115	join the network.
		116
		117	Apart from being sued for seeding, seednodes are not special in any way -
		118	every public node can be a seednode.
113		119
114	=back	120	=back
115		121
116	=head1 VARIABLES/FUNCTIONS	122	=head1 VARIABLES/FUNCTIONS
117		123
…		…
132	use base "Exporter";	138	use base "Exporter";
133		139
134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
135		141
136	our @EXPORT = qw(	142	our @EXPORT = qw(
137	NODE $NODE *SELF node_of _any_	143	NODE $NODE *SELF node_of after
138	resolve_node initialise_node	144	initialise_node
139	snd rcv mon kil reg psub spawn	145	snd rcv mon mon_guard kil reg psub spawn
140	port	146	port
141	);	147	);
142		148
143	our $SELF;	149	our $SELF;
144		150
…		…
148	kil $SELF, die => $msg;	154	kil $SELF, die => $msg;
149	}	155	}
150		156
151	=item $thisnode = NODE / $NODE	157	=item $thisnode = NODE / $NODE
152		158
153	The C<NODE> function returns, and the C<$NODE> variable contains	159	The C<NODE> function returns, and the C<$NODE> variable contains, the node
154	the noderef of the local node. The value is initialised by a call	160	ID of the node running in the current process. This value is initialised by
155	to C<become_public> or C<become_slave>, after which all local port	161	a call to C<initialise_node>.
156	identifiers become invalid.
157		162
158	=item $noderef = node_of $port	163	=item $nodeid = node_of $port
159		164
160	Extracts and returns the noderef from a portid or a noderef.	165	Extracts and returns the node ID from a port ID or a node ID.
161		166
162	=item initialise_node $noderef, $seednode, $seednode...	167	=item initialise_node $profile_name, key => value...
163		168
164	=item initialise_node "slave/", $master, $master...
165
166	Before a node can talk to other nodes on the network it has to initialise	169	Before a node can talk to other nodes on the network (i.e. enter
167	itself - the minimum a node needs to know is it's own name, and optionally	170	"distributed mode") it has to initialise itself - the minimum a node needs
168	it should know the noderefs of some other nodes in the network.	171	to know is its own name, and optionally it should know the addresses of
		172	some other nodes in the network to discover other nodes.
169		173
170	This function initialises a node - it must be called exactly once (or	174	This function initialises a node - it must be called exactly once (or
171	never) before calling other AnyEvent::MP functions.	175	never) before calling other AnyEvent::MP functions.
172		176
173	All arguments are noderefs, which can be either resolved or unresolved.	177	The first argument is a profile name. If it is C<undef> or missing, then
		178	the current nodename will be used instead (i.e. F<uname -n>).
174		179
175	There are two types of networked nodes, public nodes and slave nodes:	180	The function first looks up the profile in the aemp configuration (see the
		181	L<aemp> commandline utility). the profile is calculated as follows:
176		182
177	=over 4	183	First, all remaining key => value pairs will be used. Then they will be
		184	overwritten by any values specified in the global default configuration
		185	(see the F<aemp> utility), then the chain of profiles selected, if
		186	any. That means that the values specified in the profile have highest
		187	priority and the values specified via C<initialise_node> have lowest
		188	priority.
178		189
179	=item public nodes	190	If the profile specifies a node ID, then this will become the node ID of
		191	this process. If not, then the profile name will be used as node ID. The
		192	special node ID of C<anon/> will be replaced by a random node ID.
180		193
181	For public nodes, C<$noderef> must either be a (possibly unresolved)	194	The next step is to look up the binds in the profile, followed by binding
182	noderef, in which case it will be resolved, or C<undef> (or missing), in	195	aemp protocol listeners on all binds specified (it is possible and valid
183	which case the noderef will be guessed.	196	to have no binds, meaning that the node cannot be contacted form the
		197	outside. This means the node cannot talk to other nodes that also have no
		198	binds, but it can still talk to all "normal" nodes).
184		199
185	Afterwards, the node will bind itself on all endpoints and try to connect	200	If the profile does not specify a binds list, then the node ID will be
186	to all additional C<$seednodes> that are specified. Seednodes are optional	201	treated as if it were of the form C<host:port>, which will be resolved and
187	and can be used to quickly bootstrap the node into an existing network.	202	used as binds list.
188		203
189	=item slave nodes	204	Lastly, the seeds list from the profile is passed to the
		205	L<AnyEvent::MP::Global> module, which will then use it to keep
		206	connectivity with at least on of those seed nodes at any point in time.
190		207
191	When the C<$noderef> is the special string C<slave/>, then the node will	208	Example: become a distributed node listening on the guessed noderef, or
192	become a slave node. Slave nodes cannot be contacted from outside and will	209	the one specified via C<aemp> for the current node. This should be the
193	route most of their traffic to the master node that they attach to.	210	most common form of invocation for "daemon"-type nodes.
194
195	At least one additional noderef is required: The node will try to connect
196	to all of them and will become a slave attached to the first node it can
197	successfully connect to.
198
199	=back
200
201	This function will block until all nodes have been resolved and, for slave
202	nodes, until it has successfully established a connection to a master
203	server.
204
205	Example: become a public node listening on the default node.
206		211
207	initialise_node;	212	initialise_node;
208		213
209	Example: become a public node, and try to contact some well-known master	214	Example: become an anonymous node. This form is often used for commandline
210	servers to become part of the network.	215	clients.
211		216
212	initialise_node undef, "master1", "master2";
213
214	Example: become a public node listening on port C<4041>.
215
216	initialise_node 4041;	217	initialise_node "anon/";
217		218
218	Example: become a public node, only visible on localhost port 4044.	219	Example: become a distributed node. If there is no profile of the given
		220	name, or no binds list was specified, resolve C<localhost:4044> and bind
		221	on the resulting addresses.
219		222
220	initialise_node "locahost:4044";	223	initialise_node "localhost:4044";
221
222	Example: become a slave node to any of the specified master servers.
223
224	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
225
226	=item $cv = resolve_node $noderef
227
228	Takes an unresolved node reference that may contain hostnames and
229	abbreviated IDs, resolves all of them and returns a resolved node
230	reference.
231
232	In addition to C<address:port> pairs allowed in resolved noderefs, the
233	following forms are supported:
234
235	=over 4
236
237	=item the empty string
238
239	An empty-string component gets resolved as if the default port (4040) was
240	specified.
241
242	=item naked port numbers (e.g. C<1234>)
243
244	These are resolved by prepending the local nodename and a colon, to be
245	further resolved.
246
247	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
248
249	These are resolved by using AnyEvent::DNS to resolve them, optionally
250	looking up SRV records for the C<aemp=4040> port, if no port was
251	specified.
252
253	=back
254		224
255	=item $SELF	225	=item $SELF
256		226
257	Contains the current port id while executing C<rcv> callbacks or C<psub>	227	Contains the current port id while executing C<rcv> callbacks or C<psub>
258	blocks.	228	blocks.
259		229
260	=item SELF, %SELF, @SELF...	230	=item *SELF, SELF, %SELF, @SELF...
261		231
262	Due to some quirks in how perl exports variables, it is impossible to	232	Due to some quirks in how perl exports variables, it is impossible to
263	just export C<$SELF>, all the symbols called C<SELF> are exported by this	233	just export C<$SELF>, all the symbols named C<SELF> are exported by this
264	module, but only C<$SELF> is currently used.	234	module, but only C<$SELF> is currently used.
265		235
266	=item snd $port, type => @data	236	=item snd $port, type => @data
267		237
268	=item snd $port, @msg	238	=item snd $port, @msg
269		239
270	Send the given message to the given port ID, which can identify either	240	Send the given message to the given port, which can identify either a
271	a local or a remote port, and can be either a string or soemthignt hat	241	local or a remote port, and must be a port ID.
272	stringifies a sa port ID (such as a port object :).
273		242
274	While the message can be about anything, it is highly recommended to use a	243	While the message can be almost anything, it is highly recommended to
275	string as first element (a portid, or some word that indicates a request	244	use a string as first element (a port ID, or some word that indicates a
276	type etc.).	245	request type etc.) and to consist if only simple perl values (scalars,
		246	arrays, hashes) - if you think you need to pass an object, think again.
277		247
278	The message data effectively becomes read-only after a call to this	248	The message data logically becomes read-only after a call to this
279	function: modifying any argument is not allowed and can cause many	249	function: modifying any argument (or values referenced by them) is
280	problems.	250	forbidden, as there can be considerable time between the call to C<snd>
		251	and the time the message is actually being serialised - in fact, it might
		252	never be copied as within the same process it is simply handed to the
		253	receiving port.
281		254
282	The type of data you can transfer depends on the transport protocol: when	255	The type of data you can transfer depends on the transport protocol: when
283	JSON is used, then only strings, numbers and arrays and hashes consisting	256	JSON is used, then only strings, numbers and arrays and hashes consisting
284	of those are allowed (no objects). When Storable is used, then anything	257	of those are allowed (no objects). When Storable is used, then anything
285	that Storable can serialise and deserialise is allowed, and for the local	258	that Storable can serialise and deserialise is allowed, and for the local
286	node, anything can be passed.	259	node, anything can be passed. Best rely only on the common denominator of
		260	these.
287		261
288	=item $local_port = port	262	=item $local_port = port
289		263
290	Create a new local port object that can be used either as a pattern	264	Create a new local port object and returns its port ID. Initially it has
291	matching port ("full port") or a single-callback port ("miniport"),	265	no callbacks set and will throw an error when it receives messages.
292	depending on how C<rcv> callbacks are bound to the object.
293		266
294	=item $port = port { my @msg = @_; $finished }	267	=item $local_port = port { my @msg = @_ }
295		268
296	Creates a "miniport", that is, a very lightweight port without any pattern	269	Creates a new local port, and returns its ID. Semantically the same as
297	matching behind it, and returns its ID. Semantically the same as creating
298	a port and calling C<rcv $port, $callback> on it.	270	creating a port and calling C<rcv $port, $callback> on it.
299		271
300	The block will be called for every message received on the port. When the	272	The block will be called for every message received on the port, with the
301	callback returns a true value its job is considered "done" and the port	273	global variable C<$SELF> set to the port ID. Runtime errors will cause the
302	will be destroyed. Otherwise it will stay alive.	274	port to be C<kil>ed. The message will be passed as-is, no extra argument
		275	(i.e. no port ID) will be passed to the callback.
303		276
304	The message will be passed as-is, no extra argument (i.e. no port id) will	277	If you want to stop/destroy the port, simply C<kil> it:
305	be passed to the callback.
306		278
307	If you need the local port id in the callback, this works nicely:	279	my $port = port {
308		280	my @msg = @_;
309	my $port; $port = port {	281	...
310	snd $otherport, reply => $port;	282	kil $SELF;
311	};	283	};
312		284
313	=cut	285	=cut
314		286
315	sub rcv($@);	287	sub rcv($@);
		288
		289	sub _kilme {
		290	die "received message on port without callback";
		291	}
316		292
317	sub port(;&) {	293	sub port(;&) {
318	my $id = "$UNIQ." . $ID++;	294	my $id = "$UNIQ." . $ID++;
319	my $port = "$NODE#$id";	295	my $port = "$NODE#$id";
320		296
321	if (@_) {	297	rcv $port, shift \|\| \&_kilme;
322	rcv $port, shift;
323	} else {
324	$PORT{$id} = sub { }; # nop
325	}
326		298
327	$port	299	$port
328	}	300	}
329		301
330	=item reg $port, $name
331
332	=item reg $name
333
334	Registers the given port (or C<$SELF><<< if missing) under the name
335	C<$name>. If the name already exists it is replaced.
336
337	A port can only be registered under one well known name.
338
339	A port automatically becomes unregistered when it is killed.
340
341	=cut
342
343	sub reg(@) {
344	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
345
346	$REG{$_[0]} = $port;
347	}
348
349	=item rcv $port, $callback->(@msg)	302	=item rcv $local_port, $callback->(@msg)
350		303
351	Replaces the callback on the specified miniport (after converting it to	304	Replaces the default callback on the specified port. There is no way to
352	one if required).	305	remove the default callback: use C<sub { }> to disable it, or better
353		306	C<kil> the port when it is no longer needed.
354	=item rcv $port, tagstring => $callback->(@msg), ...
355
356	=item rcv $port, $smartmatch => $callback->(@msg), ...
357
358	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
359
360	Register callbacks to be called on matching messages on the given full
361	port (after converting it to one if required) and return the port.
362
363	The callback has to return a true value when its work is done, after
364	which is will be removed, or a false value in which case it will stay
365	registered.
366		307
367	The global C<$SELF> (exported by this module) contains C<$port> while	308	The global C<$SELF> (exported by this module) contains C<$port> while
368	executing the callback.	309	executing the callback. Runtime errors during callback execution will
		310	result in the port being C<kil>ed.
369		311
370	Runtime errors during callback execution will result in the port being	312	The default callback received all messages not matched by a more specific
371	C<kil>ed.	313	C<tag> match.
372		314
373	If the match is an array reference, then it will be matched against the	315	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
374	first elements of the message, otherwise only the first element is being
375	matched.
376		316
377	Any element in the match that is specified as C<_any_> (a function	317	Register (or replace) callbacks to be called on messages starting with the
378	exported by this module) matches any single element of the message.	318	given tag on the given port (and return the port), or unregister it (when
		319	C<$callback> is C<$undef> or missing). There can only be one callback
		320	registered for each tag.
379		321
380	While not required, it is highly recommended that the first matching	322	The original message will be passed to the callback, after the first
381	element is a string identifying the message. The one-string-only match is	323	element (the tag) has been removed. The callback will use the same
382	also the most efficient match (by far).	324	environment as the default callback (see above).
383		325
384	Example: create a port and bind receivers on it in one go.	326	Example: create a port and bind receivers on it in one go.
385		327
386	my $port = rcv port,	328	my $port = rcv port,
387	msg1 => sub { ...; 0 },	329	msg1 => sub { ... },
388	msg2 => sub { ...; 0 },	330	msg2 => sub { ... },
389	;	331	;
390		332
391	Example: create a port, bind receivers and send it in a message elsewhere	333	Example: create a port, bind receivers and send it in a message elsewhere
392	in one go:	334	in one go:
393		335
394	snd $otherport, reply =>	336	snd $otherport, reply =>
395	rcv port,	337	rcv port,
396	msg1 => sub { ...; 0 },	338	msg1 => sub { ... },
397	...	339	...
398	;	340	;
		341
		342	Example: temporarily register a rcv callback for a tag matching some port
		343	(e.g. for a rpc reply) and unregister it after a message was received.
		344
		345	rcv $port, $otherport => sub {
		346	my @reply = @_;
		347
		348	rcv $SELF, $otherport;
		349	};
399		350
400	=cut	351	=cut
401		352
402	sub rcv($@) {	353	sub rcv($@) {
403	my $port = shift;	354	my $port = shift;
404	my ($noderef, $portid) = split /#/, $port, 2;	355	my ($noderef, $portid) = split /#/, $port, 2;
405		356
406	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	357	$NODE{$noderef} == $NODE{""}
407	or Carp::croak "$port: rcv can only be called on local ports, caught";	358	or Carp::croak "$port: rcv can only be called on local ports, caught";
408		359
409	if (@_ == 1) {	360	while (@_) {
		361	if (ref $_[0]) {
		362	if (my $self = $PORT_DATA{$portid}) {
		363	"AnyEvent::MP::Port" eq ref $self
		364	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		365
		366	$self->[2] = shift;
		367	} else {
410	my $cb = shift;	368	my $cb = shift;
411	delete $PORT_DATA{$portid};
412	$PORT{$portid} = sub {	369	$PORT{$portid} = sub {
413	local $SELF = $port;	370	local $SELF = $port;
414	eval {	371	eval { &$cb }; _self_die if $@;
415	&$cb	372	};
416	and kil $port;
417	};	373	}
418	_self_die if $@;	374	} elsif (defined $_[0]) {
419	};
420	} else {
421	my $self = $PORT_DATA{$portid} \|\|= do {	375	my $self = $PORT_DATA{$portid} \|\|= do {
422	my $self = bless {	376	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
423	id => $port,
424	}, "AnyEvent::MP::Port";
425		377
426	$PORT{$portid} = sub {	378	$PORT{$portid} = sub {
427	local $SELF = $port;	379	local $SELF = $port;
428		380
429	eval {
430	for (@{ $self->{rc0}{$_[0]} }) {	381	if (my $cb = $self->[1]{$_[0]}) {
431	$_ && &{$_->[0]}	382	shift;
432	&& undef $_;	383	eval { &$cb }; _self_die if $@;
433	}	384	} else {
434
435	for (@{ $self->{rcv}{$_[0]} }) {
436	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
437	&& &{$_->[0]}	385	&{ $self->[0] };
438	&& undef $_;
439	}
440
441	for (@{ $self->{any} }) {
442	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
443	&& &{$_->[0]}
444	&& undef $_;
445	}	386	}
446	};	387	};
447	_self_die if $@;	388
		389	$self
448	};	390	};
449		391
450	$self
451	};
452
453	"AnyEvent::MP::Port" eq ref $self	392	"AnyEvent::MP::Port" eq ref $self
454	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	393	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
455		394
456	while (@_) {
457	my ($match, $cb) = splice @_, 0, 2;	395	my ($tag, $cb) = splice @_, 0, 2;
458		396
459	if (!ref $match) {	397	if (defined $cb) {
460	push @{ $self->{rc0}{$match} }, [$cb];	398	$self->[1]{$tag} = $cb;
461	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
462	my ($type, @match) = @$match;
463	@match
464	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
465	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
466	} else {	399	} else {
467	push @{ $self->{any} }, [$cb, $match];	400	delete $self->[1]{$tag};
468	}	401	}
469	}	402	}
470	}	403	}
471		404
472	$port	405	$port
…		…
508	$res	441	$res
509	}	442	}
510	}	443	}
511	}	444	}
512		445
513	=item $guard = mon $port, $cb->(@reason)	446	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
514		447
515	=item $guard = mon $port, $rcvport	448	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
516		449
517	=item $guard = mon $port	450	=item $guard = mon $port # kill $SELF when $port dies
518		451
519	=item $guard = mon $port, $rcvport, @msg	452	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
520		453
521	Monitor the given port and do something when the port is killed or	454	Monitor the given port and do something when the port is killed or
522	messages to it were lost, and optionally return a guard that can be used	455	messages to it were lost, and optionally return a guard that can be used
523	to stop monitoring again.	456	to stop monitoring again.
524		457
525	C<mon> effectively guarantees that, in the absence of hardware failures,	458	C<mon> effectively guarantees that, in the absence of hardware failures,
526	that after starting the monitor, either all messages sent to the port	459	after starting the monitor, either all messages sent to the port will
527	will arrive, or the monitoring action will be invoked after possible	460	arrive, or the monitoring action will be invoked after possible message
528	message loss has been detected. No messages will be lost "in between"	461	loss has been detected. No messages will be lost "in between" (after
529	(after the first lost message no further messages will be received by the	462	the first lost message no further messages will be received by the
530	port). After the monitoring action was invoked, further messages might get	463	port). After the monitoring action was invoked, further messages might get
531	delivered again.	464	delivered again.
		465
		466	Note that monitoring-actions are one-shot: once messages are lost (and a
		467	monitoring alert was raised), they are removed and will not trigger again.
532		468
533	In the first form (callback), the callback is simply called with any	469	In the first form (callback), the callback is simply called with any
534	number of C<@reason> elements (no @reason means that the port was deleted	470	number of C<@reason> elements (no @reason means that the port was deleted
535	"normally"). Note also that I<< the callback B<must> never die >>, so use	471	"normally"). Note also that I<< the callback B<must> never die >>, so use
536	C<eval> if unsure.	472	C<eval> if unsure.
…		…
598	is killed, the references will be freed.	534	is killed, the references will be freed.
599		535
600	Optionally returns a guard that will stop the monitoring.	536	Optionally returns a guard that will stop the monitoring.
601		537
602	This function is useful when you create e.g. timers or other watchers and	538	This function is useful when you create e.g. timers or other watchers and
603	want to free them when the port gets killed:	539	want to free them when the port gets killed (note the use of C<psub>):
604		540
605	$port->rcv (start => sub {	541	$port->rcv (start => sub {
606	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	542	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
607	undef $timer if 0.9 < rand;	543	undef $timer if 0.9 < rand;
608	});	544	});
609	});	545	});
610		546
611	=cut	547	=cut
…		…
620		556
621	=item kil $port[, @reason]	557	=item kil $port[, @reason]
622		558
623	Kill the specified port with the given C<@reason>.	559	Kill the specified port with the given C<@reason>.
624		560
625	If no C<@reason> is specified, then the port is killed "normally" (linked	561	If no C<@reason> is specified, then the port is killed "normally" (ports
626	ports will not be kileld, or even notified).	562	monitoring other ports will not necessarily die because a port dies
		563	"normally").
627		564
628	Otherwise, linked ports get killed with the same reason (second form of	565	Otherwise, linked ports get killed with the same reason (second form of
629	C<mon>, see below).	566	C<mon>, see above).
630		567
631	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	568	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
632	will be reported as reason C<< die => $@ >>.	569	will be reported as reason C<< die => $@ >>.
633		570
634	Transport/communication errors are reported as C<< transport_error =>	571	Transport/communication errors are reported as C<< transport_error =>
…		…
639	=item $port = spawn $node, $initfunc[, @initdata]	576	=item $port = spawn $node, $initfunc[, @initdata]
640		577
641	Creates a port on the node C<$node> (which can also be a port ID, in which	578	Creates a port on the node C<$node> (which can also be a port ID, in which
642	case it's the node where that port resides).	579	case it's the node where that port resides).
643		580
644	The port ID of the newly created port is return immediately, and it is	581	The port ID of the newly created port is returned immediately, and it is
645	permissible to immediately start sending messages or monitor the port.	582	possible to immediately start sending messages or to monitor the port.
646		583
647	After the port has been created, the init function is	584	After the port has been created, the init function is called on the remote
648	called. This function must be a fully-qualified function name	585	node, in the same context as a C<rcv> callback. This function must be a
649	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	586	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
650	program, use C<::name>.	587	specify a function in the main program, use C<::name>.
651		588
652	If the function doesn't exist, then the node tries to C<require>	589	If the function doesn't exist, then the node tries to C<require>
653	the package, then the package above the package and so on (e.g.	590	the package, then the package above the package and so on (e.g.
654	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	591	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
655	exists or it runs out of package names.	592	exists or it runs out of package names.
656		593
657	The init function is then called with the newly-created port as context	594	The init function is then called with the newly-created port as context
658	object (C<$SELF>) and the C<@initdata> values as arguments.	595	object (C<$SELF>) and the C<@initdata> values as arguments.
659		596
660	A common idiom is to pass your own port, monitor the spawned port, and	597	A common idiom is to pass a local port, immediately monitor the spawned
661	in the init function, monitor the original port. This two-way monitoring	598	port, and in the remote init function, immediately monitor the passed
662	ensures that both ports get cleaned up when there is a problem.	599	local port. This two-way monitoring ensures that both ports get cleaned up
		600	when there is a problem.
663		601
664	Example: spawn a chat server port on C<$othernode>.	602	Example: spawn a chat server port on C<$othernode>.
665		603
666	# this node, executed from within a port context:	604	# this node, executed from within a port context:
667	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	605	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
697	my $id = "$RUNIQ." . $ID++;	635	my $id = "$RUNIQ." . $ID++;
698		636
699	$_[0] =~ /::/	637	$_[0] =~ /::/
700	or Carp::croak "spawn init function must be a fully-qualified name, caught";	638	or Carp::croak "spawn init function must be a fully-qualified name, caught";
701		639
702	($NODE{$noderef} \|\| add_node $noderef)	640	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
703	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
704		641
705	"$noderef#$id"	642	"$noderef#$id"
706	}	643	}
707		644
708	=back	645	=item after $timeout, @msg
709		646
710	=head1 NODE MESSAGES	647	=item after $timeout, $callback
711		648
712	Nodes understand the following messages sent to them. Many of them take	649	Either sends the given message, or call the given callback, after the
713	arguments called C<@reply>, which will simply be used to compose a reply	650	specified number of seconds.
714	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
715	the remaining arguments are simply the message data.
716		651
717	While other messages exist, they are not public and subject to change.	652	This is simply a utility function that comes in handy at times - the
		653	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		654	so it may go away in the future.
718		655
719	=over 4
720
721	=cut	656	=cut
722		657
723	=item lookup => $name, @reply	658	sub after($@) {
		659	my ($timeout, @action) = @_;
724		660
725	Replies with the port ID of the specified well-known port, or C<undef>.	661	my $t; $t = AE::timer $timeout, 0, sub {
726		662	undef $t;
727	=item devnull => ...	663	ref $action[0]
728		664	? $action[0]()
729	Generic data sink/CPU heat conversion.	665	: snd @action;
730		666	};
731	=item relay => $port, @msg	667	}
732
733	Simply forwards the message to the given port.
734
735	=item eval => $string[ @reply]
736
737	Evaluates the given string. If C<@reply> is given, then a message of the
738	form C<@reply, $@, @evalres> is sent.
739
740	Example: crash another node.
741
742	snd $othernode, eval => "exit";
743
744	=item time => @reply
745
746	Replies the the current node time to C<@reply>.
747
748	Example: tell the current node to send the current time to C<$myport> in a
749	C<timereply> message.
750
751	snd $NODE, time => $myport, timereply => 1, 2;
752	# => snd $myport, timereply => 1, 2, <time>
753		668
754	=back	669	=back
755		670
756	=head1 AnyEvent::MP vs. Distributed Erlang	671	=head1 AnyEvent::MP vs. Distributed Erlang
757		672
…		…
767		682
768	Despite the similarities, there are also some important differences:	683	Despite the similarities, there are also some important differences:
769		684
770	=over 4	685	=over 4
771		686
772	=item * Node references contain the recipe on how to contact them.	687	=item * Node IDs are arbitrary strings in AEMP.
773		688
774	Erlang relies on special naming and DNS to work everywhere in the	689	Erlang relies on special naming and DNS to work everywhere in the same
775	same way. AEMP relies on each node knowing it's own address(es), with	690	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
776	convenience functionality.	691	configuraiton or DNS), but will otherwise discover other odes itself.
777		692
778	This means that AEMP requires a less tightly controlled environment at the	693	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
779	cost of longer node references and a slightly higher management overhead.	694	uses "local ports are like remote ports".
		695
		696	The failure modes for local ports are quite different (runtime errors
		697	only) then for remote ports - when a local port dies, you I<know> it dies,
		698	when a connection to another node dies, you know nothing about the other
		699	port.
		700
		701	Erlang pretends remote ports are as reliable as local ports, even when
		702	they are not.
		703
		704	AEMP encourages a "treat remote ports differently" philosophy, with local
		705	ports being the special case/exception, where transport errors cannot
		706	occur.
780		707
781	=item * Erlang uses processes and a mailbox, AEMP does not queue.	708	=item * Erlang uses processes and a mailbox, AEMP does not queue.
782		709
783	Erlang uses processes that selctively receive messages, and therefore	710	Erlang uses processes that selectively receive messages, and therefore
784	needs a queue. AEMP is event based, queuing messages would serve no useful	711	needs a queue. AEMP is event based, queuing messages would serve no
785	purpose.	712	useful purpose. For the same reason the pattern-matching abilities of
		713	AnyEvent::MP are more limited, as there is little need to be able to
		714	filter messages without dequeing them.
786		715
787	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	716	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
788		717
789	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	718	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
790		719
791	Sending messages in Erlang is synchronous and blocks the process. AEMP	720	Sending messages in Erlang is synchronous and blocks the process (and
792	sends are immediate, connection establishment is handled in the	721	so does not need a queue that can overflow). AEMP sends are immediate,
793	background.	722	connection establishment is handled in the background.
794		723
795	=item * Erlang can silently lose messages, AEMP cannot.	724	=item * Erlang suffers from silent message loss, AEMP does not.
796		725
797	Erlang makes few guarantees on messages delivery - messages can get lost	726	Erlang makes few guarantees on messages delivery - messages can get lost
798	without any of the processes realising it (i.e. you send messages a, b,	727	without any of the processes realising it (i.e. you send messages a, b,
799	and c, and the other side only receives messages a and c).	728	and c, and the other side only receives messages a and c).
800		729
801	AEMP guarantees correct ordering, and the guarantee that there are no	730	AEMP guarantees correct ordering, and the guarantee that after one message
802	holes in the message sequence.	731	is lost, all following ones sent to the same port are lost as well, until
803		732	monitoring raises an error, so there are no silent "holes" in the message
804	=item * In Erlang, processes can be declared dead and later be found to be	733	sequence.
805	alive.
806
807	In Erlang it can happen that a monitored process is declared dead and
808	linked processes get killed, but later it turns out that the process is
809	still alive - and can receive messages.
810
811	In AEMP, when port monitoring detects a port as dead, then that port will
812	eventually be killed - it cannot happen that a node detects a port as dead
813	and then later sends messages to it, finding it is still alive.
814		734
815	=item * Erlang can send messages to the wrong port, AEMP does not.	735	=item * Erlang can send messages to the wrong port, AEMP does not.
816		736
817	In Erlang it is quite possible that a node that restarts reuses a process	737	In Erlang it is quite likely that a node that restarts reuses a process ID
818	ID known to other nodes for a completely different process, causing	738	known to other nodes for a completely different process, causing messages
819	messages destined for that process to end up in an unrelated process.	739	destined for that process to end up in an unrelated process.
820		740
821	AEMP never reuses port IDs, so old messages or old port IDs floating	741	AEMP never reuses port IDs, so old messages or old port IDs floating
822	around in the network will not be sent to an unrelated port.	742	around in the network will not be sent to an unrelated port.
823		743
824	=item * Erlang uses unprotected connections, AEMP uses secure	744	=item * Erlang uses unprotected connections, AEMP uses secure
825	authentication and can use TLS.	745	authentication and can use TLS.
826		746
827	AEMP can use a proven protocol - SSL/TLS - to protect connections and	747	AEMP can use a proven protocol - TLS - to protect connections and
828	securely authenticate nodes.	748	securely authenticate nodes.
829		749
830	=item * The AEMP protocol is optimised for both text-based and binary	750	=item * The AEMP protocol is optimised for both text-based and binary
831	communications.	751	communications.
832		752
833	The AEMP protocol, unlike the Erlang protocol, supports both	753	The AEMP protocol, unlike the Erlang protocol, supports both programming
834	language-independent text-only protocols (good for debugging) and binary,	754	language independent text-only protocols (good for debugging) and binary,
835	language-specific serialisers (e.g. Storable).	755	language-specific serialisers (e.g. Storable). By default, unless TLS is
		756	used, the protocol is actually completely text-based.
836		757
837	It has also been carefully designed to be implementable in other languages	758	It has also been carefully designed to be implementable in other languages
838	with a minimum of work while gracefully degrading fucntionality to make the	759	with a minimum of work while gracefully degrading functionality to make the
839	protocol simple.	760	protocol simple.
840		761
841	=item * AEMP has more flexible monitoring options than Erlang.	762	=item * AEMP has more flexible monitoring options than Erlang.
842		763
843	In Erlang, you can chose to receive I<all> exit signals as messages	764	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
846	Erlang, as one can choose between automatic kill, exit message or callback	767	Erlang, as one can choose between automatic kill, exit message or callback
847	on a per-process basis.	768	on a per-process basis.
848		769
849	=item * Erlang tries to hide remote/local connections, AEMP does not.	770	=item * Erlang tries to hide remote/local connections, AEMP does not.
850		771
851	Monitoring in Erlang is not an indicator of process death/crashes,	772	Monitoring in Erlang is not an indicator of process death/crashes, in the
852	as linking is (except linking is unreliable in Erlang).	773	same way as linking is (except linking is unreliable in Erlang).
853		774
854	In AEMP, you don't "look up" registered port names or send to named ports	775	In AEMP, you don't "look up" registered port names or send to named ports
855	that might or might not be persistent. Instead, you normally spawn a port	776	that might or might not be persistent. Instead, you normally spawn a port
856	on the remote node. The init function monitors the you, and you monitor	777	on the remote node. The init function monitors you, and you monitor the
857	the remote port. Since both monitors are local to the node, they are much	778	remote port. Since both monitors are local to the node, they are much more
858	more reliable.	779	reliable (no need for C<spawn_link>).
859		780
860	This also saves round-trips and avoids sending messages to the wrong port	781	This also saves round-trips and avoids sending messages to the wrong port
861	(hard to do in Erlang).	782	(hard to do in Erlang).
862		783
863	=back	784	=back
864		785
865	=head1 RATIONALE	786	=head1 RATIONALE
866		787
867	=over 4	788	=over 4
868		789
869	=item Why strings for ports and noderefs, why not objects?	790	=item Why strings for port and node IDs, why not objects?
870		791
871	We considered "objects", but found that the actual number of methods	792	We considered "objects", but found that the actual number of methods
872	thatc an be called are very low. Since port IDs and noderefs travel over	793	that can be called are quite low. Since port and node IDs travel over
873	the network frequently, the serialising/deserialising would add lots of	794	the network frequently, the serialising/deserialising would add lots of
874	overhead, as well as having to keep a proxy object.	795	overhead, as well as having to keep a proxy object everywhere.
875		796
876	Strings can easily be printed, easily serialised etc. and need no special	797	Strings can easily be printed, easily serialised etc. and need no special
877	procedures to be "valid".	798	procedures to be "valid".
878		799
879	And a a miniport consists of a single closure stored in a global hash - it	800	And as a result, a miniport consists of a single closure stored in a
880	can't become much cheaper.	801	global hash - it can't become much cheaper.
881		802
882	=item Why favour JSON, why not real serialising format such as Storable?	803	=item Why favour JSON, why not a real serialising format such as Storable?
883		804
884	In fact, any AnyEvent::MP node will happily accept Storable as framing	805	In fact, any AnyEvent::MP node will happily accept Storable as framing
885	format, but currently there is no way to make a node use Storable by	806	format, but currently there is no way to make a node use Storable by
886	default.	807	default (although all nodes will accept it).
887		808
888	The default framing protocol is JSON because a) JSON::XS is many times	809	The default framing protocol is JSON because a) JSON::XS is many times
889	faster for small messages and b) most importantly, after years of	810	faster for small messages and b) most importantly, after years of
890	experience we found that object serialisation is causing more problems	811	experience we found that object serialisation is causing more problems
891	than it gains: Just like function calls, objects simply do not travel	812	than it solves: Just like function calls, objects simply do not travel
892	easily over the network, mostly because they will always be a copy, so you	813	easily over the network, mostly because they will always be a copy, so you
893	always have to re-think your design.	814	always have to re-think your design.
894		815
895	Keeping your messages simple, concentrating on data structures rather than	816	Keeping your messages simple, concentrating on data structures rather than
896	objects, will keep your messages clean, tidy and efficient.	817	objects, will keep your messages clean, tidy and efficient.
897		818
898	=back	819	=back
899		820
900	=head1 SEE ALSO	821	=head1 SEE ALSO
901		822
		823	L<AnyEvent::MP::Intro> - a gentle introduction.
		824
		825	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		826
		827	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		828	your applications.
		829
902	L<AnyEvent>.	830	L<AnyEvent>.
903		831
904	=head1 AUTHOR	832	=head1 AUTHOR
905		833
906	Marc Lehmann <schmorp@schmorp.de>	834	Marc Lehmann <schmorp@schmorp.de>

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Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs.
Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC