[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 1.69 by root, Sun Aug 30 18:51:49 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;
14		17
15	# ports are message endpoints	18	# ports are message endpoints
16		19
17	# sending messages	20	# sending messages
18	snd $port, type => data...;	21	snd $port, type => data...;
19	snd $port, @msg;	22	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
21		24
22	# miniports	25	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
24		27
25	# full ports	28	# creating/using ports, tagged message matching
26	my $port = port;	29	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		32
31	# remote ports	33	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	34	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		35
38	# monitoring	36	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	37	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	38	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	39	mon $port, $otherport, @msg # send message on death
42		40
		41	=head1 CURRENT STATUS
		42
		43	AnyEvent::MP - stable API, should work
		44	AnyEvent::MP::Intro - outdated
		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
		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
48	on the same or other hosts.	57	on the same or other hosts, and you can supervise entities remotely.
49		58
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 and the examples under F<eg/>.
52		61
53	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is a bit underdocumented.
54	so do not use. This was uploaded mainly to reserve the CPAN namespace -
55	stay tuned! The basic API should be finished, however.
56		63
57	=head1 CONCEPTS	64	=head1 CONCEPTS
58		65
59	=over 4	66	=over 4
60		67
61	=item port	68	=item port
62		69
63	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).
64		71
65	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
66	messages. All C<rcv> handlers will receive messages they match, messages	73	some messages. Messages send to ports will not be queued, regardless of
67	will not be queued.	74	anything was listening for them or not.
68		75
69	=item port id - C<noderef#portname>	76	=item port ID - C<nodeid#portname>
70		77
71	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
72	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format).
73	exception is the the node port, whose ID is identical to its node
74	reference.
75		80
76	=item node	81	=item node
77		82
78	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,
79	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
80	create new ports, among other things.	85	ports.
81		86
82	Nodes are either private (single-process only), slaves (connected to a	87	Nodes are either public (have one or more listening ports) or private
83	master node only) or public nodes (connectable from unrelated nodes).	88	(no listening ports). Private nodes cannot talk to other private nodes
		89	currently.
84		90
85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	91	=item node ID - C<[a-za-Z0-9_\-.:]+>
86		92
87	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
88	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
89	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.
90		97
91	This recipe is simply a comma-separated list of C<address:port> pairs (for	98	=item binds - C<ip:port>
92	TCP/IP, other protocols might look different).
93		99
94	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
95	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.
96		104
97	Before using an unresolved node reference in a message you first have to	105	=item seeds - C<host:port>
98	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.
99		119
100	=back	120	=back
101		121
102	=head1 VARIABLES/FUNCTIONS	122	=head1 VARIABLES/FUNCTIONS
103		123
…		…
105		125
106	=cut	126	=cut
107		127
108	package AnyEvent::MP;	128	package AnyEvent::MP;
109		129
110	use AnyEvent::MP::Base;	130	use AnyEvent::MP::Kernel;
111		131
112	use common::sense;	132	use common::sense;
113		133
114	use Carp ();	134	use Carp ();
115		135
116	use AE ();	136	use AE ();
117		137
118	use base "Exporter";	138	use base "Exporter";
119		139
120	our $VERSION = $AnyEvent::MP::Base::VERSION;	140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
121		141
122	our @EXPORT = qw(	142	our @EXPORT = qw(
123	NODE $NODE *SELF node_of _any_	143	NODE $NODE *SELF node_of after
124	resolve_node initialise_node	144	initialise_node
125	snd rcv mon kil reg psub spawn	145	snd rcv mon mon_guard kil reg psub spawn
126	port	146	port
127	);	147	);
128		148
129	our $SELF;	149	our $SELF;
130		150
…		…
134	kil $SELF, die => $msg;	154	kil $SELF, die => $msg;
135	}	155	}
136		156
137	=item $thisnode = NODE / $NODE	157	=item $thisnode = NODE / $NODE
138		158
139	The C<NODE> function returns, and the C<$NODE> variable contains	159	The C<NODE> function returns, and the C<$NODE> variable contains, the node
140	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
141	to C<become_public> or C<become_slave>, after which all local port	161	a call to C<initialise_node>.
142	identifiers become invalid.
143		162
144	=item $noderef = node_of $port	163	=item $nodeid = node_of $port
145		164
146	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.
147		166
148	=item initialise_node $noderef, $seednode, $seednode...	167	=item initialise_node $profile_name, key => value...
149		168
150	=item initialise_node "slave/", $master, $master...
151
152	Before a node can talk to other nodes on the network it has to initialise	169	Before a node can talk to other nodes on the network (i.e. enter
153	itself - the minimum a node needs to know is it's own name, and optionally	170	"distributed mode") it has to initialise itself - the minimum a node needs
154	it should know the noderefs of some other nodes in the network.	171	to know is its own name, and optionally it should know the addresses of
		172	some other nodes in the network to discover other nodes.
155		173
156	This function initialises a node - it must be called exactly once (or	174	This function initialises a node - it must be called exactly once (or
157	never) before calling other AnyEvent::MP functions.	175	never) before calling other AnyEvent::MP functions.
158		176
159	All arguments are noderefs, which can be either resolved or unresolved.	177	The first argument is a profile name. If it is C<undef> or missing, then
		178	the current nodename will be used instead (i.e. F<uname -n>).
160		179
161	There are two types of networked nodes, public nodes and slave nodes:	180	The function first looks up the profile in the aemp configuration (see the
		181	L<aemp> commandline utility). the profile is calculated as follows:
162		182
163	=over 4	183	First, all remaining key => value pairs will be used. Then they will be
		184	overwritten by any values specified in the global default configuration
		185	(see the F<aemp> utility), then the chain of profiles selected, if
		186	any. That means that the values specified in the profile have highest
		187	priority and the values specified via C<initialise_node> have lowest
		188	priority.
164		189
165	=item public nodes	190	If the profile specifies a node ID, then this will become the node ID of
		191	this process. If not, then the profile name will be used as node ID. The
		192	special node ID of C<anon/> will be replaced by a random node ID.
166		193
167	For public nodes, C<$noderef> must either be a (possibly unresolved)	194	The next step is to look up the binds in the profile, followed by binding
168	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
169	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).
170		199
171	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
172	to all additional C<$seednodes> that are specified. Seednodes are optional	201	treated as if it were of the form C<host:port>, which will be resolved and
173	and can be used to quickly bootstrap the node into an existing network.	202	used as binds list.
174		203
175	=item slave nodes	204	Lastly, the seeds list from the profile is passed to the
		205	L<AnyEvent::MP::Global> module, which will then use it to keep
		206	connectivity with at least on of those seed nodes at any point in time.
176		207
177	When the C<$noderef> is the special string C<slave/>, then the node will	208	Example: become a distributed node listening on the guessed noderef, or
178	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
179	route most of their traffic to the master node that they attach to.	210	most common form of invocation for "daemon"-type nodes.
180
181	At least one additional noderef is required: The node will try to connect
182	to all of them and will become a slave attached to the first node it can
183	successfully connect to.
184
185	=back
186
187	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
189	server.
190
191	Example: become a public node listening on the default node.
192		211
193	initialise_node;	212	initialise_node;
194		213
195	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
196	servers to become part of the network.	215	clients.
197		216
198	initialise_node undef, "master1", "master2";
199
200	Example: become a public node listening on port C<4041>.
201
202	initialise_node 4041;	217	initialise_node "anon/";
203		218
204	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.
205		222
206	initialise_node "locahost:4044";	223	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
212	=item $cv = resolve_node $noderef
213
214	Takes an unresolved node reference that may contain hostnames and
215	abbreviated IDs, resolves all of them and returns a resolved node
216	reference.
217
218	In addition to C<address:port> pairs allowed in resolved noderefs, the
219	following forms are supported:
220
221	=over 4
222
223	=item the empty string
224
225	An empty-string component gets resolved as if the default port (4040) was
226	specified.
227
228	=item naked port numbers (e.g. C<1234>)
229
230	These are resolved by prepending the local nodename and a colon, to be
231	further resolved.
232
233	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
234
235	These are resolved by using AnyEvent::DNS to resolve them, optionally
236	looking up SRV records for the C<aemp=4040> port, if no port was
237	specified.
238
239	=back
240		224
241	=item $SELF	225	=item $SELF
242		226
243	Contains the current port id while executing C<rcv> callbacks or C<psub>	227	Contains the current port id while executing C<rcv> callbacks or C<psub>
244	blocks.	228	blocks.
245		229
246	=item SELF, %SELF, @SELF...	230	=item *SELF, SELF, %SELF, @SELF...
247		231
248	Due to some quirks in how perl exports variables, it is impossible to	232	Due to some quirks in how perl exports variables, it is impossible to
249	just export C<$SELF>, all the symbols called C<SELF> are exported by this	233	just export C<$SELF>, all the symbols named C<SELF> are exported by this
250	module, but only C<$SELF> is currently used.	234	module, but only C<$SELF> is currently used.
251		235
252	=item snd $port, type => @data	236	=item snd $port, type => @data
253		237
254	=item snd $port, @msg	238	=item snd $port, @msg
255		239
256	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
257	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.
258	stringifies a sa port ID (such as a port object :).
259		242
260	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
261	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
262	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.
263		247
264	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
265	function: modifying any argument is not allowed and can cause many	249	function: modifying any argument (or values referenced by them) is
266	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.
267		254
268	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
269	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
270	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
271	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
272	node, anything can be passed.	259	node, anything can be passed. Best rely only on the common denominator of
		260	these.
273		261
274	=item $local_port = port	262	=item $local_port = port
275		263
276	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
277	matching port ("full port") or a single-callback port ("miniport"),	265	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		266
280	=item $port = port { my @msg = @_; $finished }	267	=item $local_port = port { my @msg = @_ }
281		268
282	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
283	matching behind it, and returns its ID. Semantically the same as creating
284	a port and calling C<rcv $port, $callback> on it.	270	creating a port and calling C<rcv $port, $callback> on it.
285		271
286	The block will be called for every message received on the port. When the	272	The block will be called for every message received on the port, with the
287	callback returns a true value its job is considered "done" and the port	273	global variable C<$SELF> set to the port ID. Runtime errors will cause the
288	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.
289		276
290	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:
291	be passed to the callback.
292		278
293	If you need the local port id in the callback, this works nicely:	279	my $port = port {
294		280	my @msg = @_;
295	my $port; $port = port {	281	...
296	snd $otherport, reply => $port;	282	kil $SELF;
297	};	283	};
298		284
299	=cut	285	=cut
300		286
301	sub rcv($@);	287	sub rcv($@);
		288
		289	sub _kilme {
		290	die "received message on port without callback";
		291	}
302		292
303	sub port(;&) {	293	sub port(;&) {
304	my $id = "$UNIQ." . $ID++;	294	my $id = "$UNIQ." . $ID++;
305	my $port = "$NODE#$id";	295	my $port = "$NODE#$id";
306		296
307	if (@_) {	297	rcv $port, shift \|\| \&_kilme;
308	rcv $port, shift;
309	} else {
310	$PORT{$id} = sub { }; # nop
311	}
312		298
313	$port	299	$port
314	}	300	}
315		301
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)	302	=item rcv $local_port, $callback->(@msg)
336		303
337	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
338	one if required).	305	remove the default callback: use C<sub { }> to disable it, or better
339		306	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...] => $callback->(@msg), ...
345
346	Register callbacks to be called on matching messages on the given full
347	port (after converting it to one if required) and return the port.
348
349	The callback has to return a true value when its work is done, after
350	which is will be removed, or a false value in which case it will stay
351	registered.
352		307
353	The global C<$SELF> (exported by this module) contains C<$port> while	308	The global C<$SELF> (exported by this module) contains C<$port> while
354	executing the callback.	309	executing the callback. Runtime errors during callback execution will
		310	result in the port being C<kil>ed.
355		311
356	Runtime errors during callback execution will result in the port being	312	The default callback received all messages not matched by a more specific
357	C<kil>ed.	313	C<tag> match.
358		314
359	If the match is an array reference, then it will be matched against the	315	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
360	first elements of the message, otherwise only the first element is being
361	matched.
362		316
363	Any element in the match that is specified as C<_any_> (a function	317	Register (or replace) callbacks to be called on messages starting with the
364	exported by this module) matches any single element of the message.	318	given tag on the given port (and return the port), or unregister it (when
		319	C<$callback> is C<$undef> or missing). There can only be one callback
		320	registered for each tag.
365		321
366	While not required, it is highly recommended that the first matching	322	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	323	element (the tag) has been removed. The callback will use the same
368	also the most efficient match (by far).	324	environment as the default callback (see above).
369		325
370	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.
371		327
372	my $port = rcv port,	328	my $port = rcv port,
373	msg1 => sub { ...; 0 },	329	msg1 => sub { ... },
374	msg2 => sub { ...; 0 },	330	msg2 => sub { ... },
375	;	331	;
376		332
377	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
378	in one go:	334	in one go:
379		335
380	snd $otherport, reply =>	336	snd $otherport, reply =>
381	rcv port,	337	rcv port,
382	msg1 => sub { ...; 0 },	338	msg1 => sub { ... },
383	...	339	...
384	;	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, $otherport;
		349	};
385		350
386	=cut	351	=cut
387		352
388	sub rcv($@) {	353	sub rcv($@) {
389	my $port = shift;	354	my $port = shift;
390	my ($noderef, $portid) = split /#/, $port, 2;	355	my ($noderef, $portid) = split /#/, $port, 2;
391		356
392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	357	$NODE{$noderef} == $NODE{""}
393	or Carp::croak "$port: rcv can only be called on local ports, caught";	358	or Carp::croak "$port: rcv can only be called on local ports, caught";
394		359
395	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 {
396	my $cb = shift;	368	my $cb = shift;
397	delete $PORT_DATA{$portid};
398	$PORT{$portid} = sub {	369	$PORT{$portid} = sub {
399	local $SELF = $port;	370	local $SELF = $port;
400	eval {	371	eval { &$cb }; _self_die if $@;
401	&$cb	372	};
402	and kil $port;
403	};	373	}
404	_self_die if $@;	374	} elsif (defined $_[0]) {
405	};
406	} else {
407	my $self = $PORT_DATA{$portid} \|\|= do {	375	my $self = $PORT_DATA{$portid} \|\|= do {
408	my $self = bless {	376	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
409	id => $port,
410	}, "AnyEvent::MP::Port";
411		377
412	$PORT{$portid} = sub {	378	$PORT{$portid} = sub {
413	local $SELF = $port;	379	local $SELF = $port;
414		380
415	eval {
416	for (@{ $self->{rc0}{$_[0]} }) {	381	if (my $cb = $self->[1]{$_[0]}) {
417	$_ && &{$_->[0]}	382	shift;
418	&& undef $_;	383	eval { &$cb }; _self_die if $@;
419	}	384	} else {
420
421	for (@{ $self->{rcv}{$_[0]} }) {
422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
423	&& &{$_->[0]}	385	&{ $self->[0] };
424	&& undef $_;
425	}
426
427	for (@{ $self->{any} }) {
428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
429	&& &{$_->[0]}
430	&& undef $_;
431	}	386	}
432	};	387	};
433	_self_die if $@;	388
		389	$self
434	};	390	};
435		391
436	$self
437	};
438
439	"AnyEvent::MP::Port" eq ref $self	392	"AnyEvent::MP::Port" eq ref $self
440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	393	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
441		394
442	while (@_) {
443	my ($match, $cb) = splice @_, 0, 2;	395	my ($tag, $cb) = splice @_, 0, 2;
444		396
445	if (!ref $match) {	397	if (defined $cb) {
446	push @{ $self->{rc0}{$match} }, [$cb];	398	$self->[1]{$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 {	399	} else {
453	push @{ $self->{any} }, [$cb, $match];	400	delete $self->[1]{$tag};
454	}	401	}
455	}	402	}
456	}	403	}
457		404
458	$port	405	$port
…		…
494	$res	441	$res
495	}	442	}
496	}	443	}
497	}	444	}
498		445
499	=item $guard = mon $port, $cb->(@reason)	446	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
500		447
501	=item $guard = mon $port, $rcvport	448	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
502		449
503	=item $guard = mon $port	450	=item $guard = mon $port # kill $SELF when $port dies
504		451
505	=item $guard = mon $port, $rcvport, @msg	452	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
506		453
507	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
508	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
509	to stop monitoring again.	456	to stop monitoring again.
510		457
511	C<mon> effectively guarantees that, in the absence of hardware failures,	458	C<mon> effectively guarantees that, in the absence of hardware failures,
512	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
513	will arrive, or the monitoring action will be invoked after possible	460	arrive, or the monitoring action will be invoked after possible message
514	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
515	(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
516	port). After the monitoring action was invoked, further messages might get	463	port). After the monitoring action was invoked, further messages might get
517	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.
518		468
519	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
520	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
521	"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
522	C<eval> if unsure.	472	C<eval> if unsure.
…		…
584	is killed, the references will be freed.	534	is killed, the references will be freed.
585		535
586	Optionally returns a guard that will stop the monitoring.	536	Optionally returns a guard that will stop the monitoring.
587		537
588	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
589	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>):
590		540
591	$port->rcv (start => sub {	541	$port->rcv (start => sub {
592	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	542	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
593	undef $timer if 0.9 < rand;	543	undef $timer if 0.9 < rand;
594	});	544	});
595	});	545	});
596		546
597	=cut	547	=cut
…		…
606		556
607	=item kil $port[, @reason]	557	=item kil $port[, @reason]
608		558
609	Kill the specified port with the given C<@reason>.	559	Kill the specified port with the given C<@reason>.
610		560
611	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
612	ports will not be kileld, or even notified).	562	monitoring other ports will not necessarily die because a port dies
		563	"normally").
613		564
614	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
615	C<mon>, see below).	566	C<mon>, see above).
616		567
617	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
618	will be reported as reason C<< die => $@ >>.	569	will be reported as reason C<< die => $@ >>.
619		570
620	Transport/communication errors are reported as C<< transport_error =>	571	Transport/communication errors are reported as C<< transport_error =>
…		…
625	=item $port = spawn $node, $initfunc[, @initdata]	576	=item $port = spawn $node, $initfunc[, @initdata]
626		577
627	Creates a port on the node C<$node> (which can also be a port ID, in which	578	Creates a port on the node C<$node> (which can also be a port ID, in which
628	case it's the node where that port resides).	579	case it's the node where that port resides).
629		580
630	The port ID of the newly created port is return immediately, and it is	581	The port ID of the newly created port is returned immediately, and it is
631	permissible to immediately start sending messages or monitor the port.	582	possible to immediately start sending messages or to monitor the port.
632		583
633	After the port has been created, the init function is	584	After the port has been created, the init function is called on the remote
634	called. This function must be a fully-qualified function name	585	node, in the same context as a C<rcv> callback. This function must be a
635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	586	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
636	program, use C<::name>.	587	specify a function in the main program, use C<::name>.
637		588
638	If the function doesn't exist, then the node tries to C<require>	589	If the function doesn't exist, then the node tries to C<require>
639	the package, then the package above the package and so on (e.g.	590	the package, then the package above the package and so on (e.g.
640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	591	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
641	exists or it runs out of package names.	592	exists or it runs out of package names.
642		593
643	The init function is then called with the newly-created port as context	594	The init function is then called with the newly-created port as context
644	object (C<$SELF>) and the C<@initdata> values as arguments.	595	object (C<$SELF>) and the C<@initdata> values as arguments.
645		596
646	A common idiom is to pass your own port, monitor the spawned port, and	597	A common idiom is to pass a local port, immediately monitor the spawned
647	in the init function, monitor the original port. This two-way monitoring	598	port, and in the remote init function, immediately monitor the passed
648	ensures that both ports get cleaned up when there is a problem.	599	local port. This two-way monitoring ensures that both ports get cleaned up
		600	when there is a problem.
649		601
650	Example: spawn a chat server port on C<$othernode>.	602	Example: spawn a chat server port on C<$othernode>.
651		603
652	# this node, executed from within a port context:	604	# this node, executed from within a port context:
653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	605	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
683	my $id = "$RUNIQ." . $ID++;	635	my $id = "$RUNIQ." . $ID++;
684		636
685	$_[0] =~ /::/	637	$_[0] =~ /::/
686	or Carp::croak "spawn init function must be a fully-qualified name, caught";	638	or Carp::croak "spawn init function must be a fully-qualified name, caught";
687		639
688	($NODE{$noderef} \|\| add_node $noderef)	640	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
690		641
691	"$noderef#$id"	642	"$noderef#$id"
692	}	643	}
693		644
694	=back	645	=item after $timeout, @msg
695		646
696	=head1 NODE MESSAGES	647	=item after $timeout, $callback
697		648
698	Nodes understand the following messages sent to them. Many of them take	649	Either sends the given message, or call the given callback, after the
699	arguments called C<@reply>, which will simply be used to compose a reply	650	specified number of seconds.
700	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
701	the remaining arguments are simply the message data.
702		651
703	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.
704		655
705	=over 4
706
707	=cut	656	=cut
708		657
709	=item lookup => $name, @reply	658	sub after($@) {
		659	my ($timeout, @action) = @_;
710		660
711	Replies with the port ID of the specified well-known port, or C<undef>.	661	my $t; $t = AE::timer $timeout, 0, sub {
712		662	undef $t;
713	=item devnull => ...	663	ref $action[0]
714		664	? $action[0]()
715	Generic data sink/CPU heat conversion.	665	: snd @action;
716		666	};
717	=item relay => $port, @msg	667	}
718
719	Simply forwards the message to the given port.
720
721	=item eval => $string[ @reply]
722
723	Evaluates the given string. If C<@reply> is given, then a message of the
724	form C<@reply, $@, @evalres> is sent.
725
726	Example: crash another node.
727
728	snd $othernode, eval => "exit";
729
730	=item time => @reply
731
732	Replies the the current node time to C<@reply>.
733
734	Example: tell the current node to send the current time to C<$myport> in a
735	C<timereply> message.
736
737	snd $NODE, time => $myport, timereply => 1, 2;
738	# => snd $myport, timereply => 1, 2, <time>
739		668
740	=back	669	=back
741		670
742	=head1 AnyEvent::MP vs. Distributed Erlang	671	=head1 AnyEvent::MP vs. Distributed Erlang
743		672
…		…
753		682
754	Despite the similarities, there are also some important differences:	683	Despite the similarities, there are also some important differences:
755		684
756	=over 4	685	=over 4
757		686
758	=item * Node references contain the recipe on how to contact them.	687	=item * Node IDs are arbitrary strings in AEMP.
759		688
760	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
761	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
762	convenience functionality.	691	configuraiton or DNS), but will otherwise discover other odes itself.
763		692
764	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
765	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.
766		707
767	=item * Erlang uses processes and a mailbox, AEMP does not queue.	708	=item * Erlang uses processes and a mailbox, AEMP does not queue.
768		709
769	Erlang uses processes that selctively receive messages, and therefore	710	Erlang uses processes that selectively receive messages, and therefore
770	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
771	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.
772		715
773	(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).
774		717
775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	718	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
776		719
777	Sending messages in Erlang is synchronous and blocks the process. AEMP	720	Sending messages in Erlang is synchronous and blocks the process (and
778	sends are immediate, connection establishment is handled in the	721	so does not need a queue that can overflow). AEMP sends are immediate,
779	background.	722	connection establishment is handled in the background.
780		723
781	=item * Erlang can silently lose messages, AEMP cannot.	724	=item * Erlang suffers from silent message loss, AEMP does not.
782		725
783	Erlang makes few guarantees on messages delivery - messages can get lost	726	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,	727	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).	728	and c, and the other side only receives messages a and c).
786		729
787	AEMP guarantees correct ordering, and the guarantee that there are no	730	AEMP guarantees correct ordering, and the guarantee that after one message
788	holes in the message sequence.	731	is lost, all following ones sent to the same port are lost as well, until
789		732	monitoring raises an error, so there are no silent "holes" in the message
790	=item * In Erlang, processes can be declared dead and later be found to be	733	sequence.
791	alive.
792
793	In Erlang it can happen that a monitored process is declared dead and
794	linked processes get killed, but later it turns out that the process is
795	still alive - and can receive messages.
796
797	In AEMP, when port monitoring detects a port as dead, then that port will
798	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.
800		734
801	=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.
802		736
803	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
804	ID known to other nodes for a completely different process, causing	738	known to other nodes for a completely different process, causing messages
805	messages destined for that process to end up in an unrelated process.	739	destined for that process to end up in an unrelated process.
806		740
807	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
808	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.
809		743
810	=item * Erlang uses unprotected connections, AEMP uses secure	744	=item * Erlang uses unprotected connections, AEMP uses secure
811	authentication and can use TLS.	745	authentication and can use TLS.
812		746
813	AEMP can use a proven protocol - SSL/TLS - to protect connections and	747	AEMP can use a proven protocol - TLS - to protect connections and
814	securely authenticate nodes.	748	securely authenticate nodes.
815		749
816	=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
817	communications.	751	communications.
818		752
819	The AEMP protocol, unlike the Erlang protocol, supports both	753	The AEMP protocol, unlike the Erlang protocol, supports both programming
820	language-independent text-only protocols (good for debugging) and binary,	754	language independent text-only protocols (good for debugging) and binary,
821	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.
822		757
823	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
824	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
825	protocol simple.	760	protocol simple.
826		761
827	=item * AEMP has more flexible monitoring options than Erlang.	762	=item * AEMP has more flexible monitoring options than Erlang.
828		763
829	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
…		…
832	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
833	on a per-process basis.	768	on a per-process basis.
834		769
835	=item * Erlang tries to hide remote/local connections, AEMP does not.	770	=item * Erlang tries to hide remote/local connections, AEMP does not.
836		771
837	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
838	as linking is (except linking is unreliable in Erlang).	773	same way as linking is (except linking is unreliable in Erlang).
839		774
840	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
841	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
842	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
843	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
844	more reliable.	779	reliable (no need for C<spawn_link>).
845		780
846	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
847	(hard to do in Erlang).	782	(hard to do in Erlang).
848		783
849	=back	784	=back
850		785
		786	=head1 RATIONALE
		787
		788	=over 4
		789
		790	=item Why strings for port and node IDs, why not objects?
		791
		792	We considered "objects", but found that the actual number of methods
		793	that can be called are quite low. Since port and node IDs travel over
		794	the network frequently, the serialising/deserialising would add lots of
		795	overhead, as well as having to keep a proxy object everywhere.
		796
		797	Strings can easily be printed, easily serialised etc. and need no special
		798	procedures to be "valid".
		799
		800	And as a result, a miniport consists of a single closure stored in a
		801	global hash - it can't become much cheaper.
		802
		803	=item Why favour JSON, why not a real serialising format such as Storable?
		804
		805	In fact, any AnyEvent::MP node will happily accept Storable as framing
		806	format, but currently there is no way to make a node use Storable by
		807	default (although all nodes will accept it).
		808
		809	The default framing protocol is JSON because a) JSON::XS is many times
		810	faster for small messages and b) most importantly, after years of
		811	experience we found that object serialisation is causing more problems
		812	than it solves: Just like function calls, objects simply do not travel
		813	easily over the network, mostly because they will always be a copy, so you
		814	always have to re-think your design.
		815
		816	Keeping your messages simple, concentrating on data structures rather than
		817	objects, will keep your messages clean, tidy and efficient.
		818
		819	=back
		820
851	=head1 SEE ALSO	821	=head1 SEE ALSO
		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.
852		829
853	L<AnyEvent>.	830	L<AnyEvent>.
854		831
855	=head1 AUTHOR	832	=head1 AUTHOR
856		833

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Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs.
Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC