[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 1.71 by root, Sun Aug 30 19:52:56 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	bin/aemp - stable.
		44	AnyEvent::MP - stable API, should work.
		45	AnyEvent::MP::Intro - uptodate, but incomplete.
		46	AnyEvent::MP::Kernel - mostly stable.
		47	AnyEvent::MP::Global - stable API, protocol not yet final.
		48
		49	stay tuned.
		50
43	=head1 DESCRIPTION	51	=head1 DESCRIPTION
44		52
45	This module (-family) implements a simple message passing framework.	53	This module (-family) implements a simple message passing framework.
46		54
47	Despite its simplicity, you can securely message other processes running	55	Despite its simplicity, you can securely message other processes running
48	on the same or other hosts.	56	on the same or other hosts, and you can supervise entities remotely.
49		57
50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	58	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
51	manual page.	59	manual page and the examples under F<eg/>.
52		60
53	At the moment, this module family is severly broken and underdocumented,	61	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		62
57	=head1 CONCEPTS	63	=head1 CONCEPTS
58		64
59	=over 4	65	=over 4
60		66
61	=item port	67	=item port
62		68
63	A port is something you can send messages to (with the C<snd> function).	69	A port is something you can send messages to (with the C<snd> function).
64		70
65	Some ports allow you to register C<rcv> handlers that can match specific	71	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	72	some messages. Messages send to ports will not be queued, regardless of
67	will not be queued.	73	anything was listening for them or not.
68		74
69	=item port id - C<noderef#portname>	75	=item port ID - C<nodeid#portname>
70		76
71	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	77	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	78	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		79
76	=item node	80	=item node
77		81
78	A node is a single process containing at least one port - the node	82	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	83	which enables nodes to manage each other remotely, and to create new
80	create new ports, among other things.	84	ports.
81		85
82	Nodes are either private (single-process only), slaves (connected to a	86	Nodes are either public (have one or more listening ports) or private
83	master node only) or public nodes (connectable from unrelated nodes).	87	(no listening ports). Private nodes cannot talk to other private nodes
		88	currently.
84		89
85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	90	=item node ID - C<[a-za-Z0-9_\-.:]+>
86		91
87	A node reference is a string that either simply identifies the node (for	92	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	93	network. Depending on the configuration used, node IDs can look like a
89	node (for public nodes).	94	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		95	doesn't interpret node IDs in any way.
90		96
91	This recipe is simply a comma-separated list of C<address:port> pairs (for	97	=item binds - C<ip:port>
92	TCP/IP, other protocols might look different).
93		98
94	Node references come in two flavours: resolved (containing only numerical	99	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).	100	each other. To do this, nodes should listen on one or more local transport
		101	endpoints - binds. Currently, only standard C<ip:port> specifications can
		102	be used, which specify TCP ports to listen on.
96		103
97	Before using an unresolved node reference in a message you first have to	104	=item seeds - C<host:port>
98	resolve it.	105
		106	When a node starts, it knows nothing about the network. To teach the node
		107	about the network it first has to contact some other node within the
		108	network. This node is called a seed.
		109
		110	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		111	are expected to be long-running, and at least one of those should always
		112	be available. When nodes run out of connections (e.g. due to a network
		113	error), they try to re-establish connections to some seednodes again to
		114	join the network.
		115
		116	Apart from being sued for seeding, seednodes are not special in any way -
		117	every public node can be a seednode.
99		118
100	=back	119	=back
101		120
102	=head1 VARIABLES/FUNCTIONS	121	=head1 VARIABLES/FUNCTIONS
103		122
…		…
105		124
106	=cut	125	=cut
107		126
108	package AnyEvent::MP;	127	package AnyEvent::MP;
109		128
110	use AnyEvent::MP::Base;	129	use AnyEvent::MP::Kernel;
111		130
112	use common::sense;	131	use common::sense;
113		132
114	use Carp ();	133	use Carp ();
115		134
116	use AE ();	135	use AE ();
117		136
118	use base "Exporter";	137	use base "Exporter";
119		138
120	our $VERSION = $AnyEvent::MP::Base::VERSION;	139	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
121		140
122	our @EXPORT = qw(	141	our @EXPORT = qw(
123	NODE $NODE *SELF node_of _any_	142	NODE $NODE *SELF node_of after
124	resolve_node initialise_node	143	initialise_node
125	snd rcv mon kil reg psub spawn	144	snd rcv mon mon_guard kil reg psub spawn
126	port	145	port
127	);	146	);
128		147
129	our $SELF;	148	our $SELF;
130		149
…		…
134	kil $SELF, die => $msg;	153	kil $SELF, die => $msg;
135	}	154	}
136		155
137	=item $thisnode = NODE / $NODE	156	=item $thisnode = NODE / $NODE
138		157
139	The C<NODE> function returns, and the C<$NODE> variable contains	158	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	159	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	160	a call to C<initialise_node>.
142	identifiers become invalid.
143		161
144	=item $noderef = node_of $port	162	=item $nodeid = node_of $port
145		163
146	Extracts and returns the noderef from a portid or a noderef.	164	Extracts and returns the node ID from a port ID or a node ID.
147		165
148	=item initialise_node $noderef, $seednode, $seednode...	166	=item initialise_node $profile_name, key => value...
149		167
150	=item initialise_node "slave/", $master, $master...
151
152	Before a node can talk to other nodes on the network it has to initialise	168	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	169	"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.	170	to know is its own name, and optionally it should know the addresses of
		171	some other nodes in the network to discover other nodes.
155		172
156	This function initialises a node - it must be called exactly once (or	173	This function initialises a node - it must be called exactly once (or
157	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
158		175
159	All arguments are noderefs, which can be either resolved or unresolved.	176	The first argument is a profile name. If it is C<undef> or missing, then
		177	the current nodename will be used instead (i.e. F<uname -n>).
160		178
161	There are two types of networked nodes, public nodes and slave nodes:	179	The function first looks up the profile in the aemp configuration (see the
		180	L<aemp> commandline utility). the profile is calculated as follows:
162		181
163	=over 4	182	First, all remaining key => value pairs (all of which are conviniently
		183	undocumented at the moment) will be used. Then they will be overwritten by
		184	any values specified in the global default configuration (see the F<aemp>
		185	utility), then the chain of profiles selected, if any. That means that
		186	the values specified in the profile have highest priority and the values
		187	specified via C<initialise_node> have lowest priority.
164		188
165	=item public nodes	189	If the profile specifies a node ID, then this will become the node ID of
		190	this process. If not, then the profile name will be used as node ID. The
		191	special node ID of C<anon/> will be replaced by a random node ID.
166		192
167	For public nodes, C<$noderef> must either be a (possibly unresolved)	193	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	194	aemp protocol listeners on all binds specified (it is possible and valid
169	which case the noderef will be guessed.	195	to have no binds, meaning that the node cannot be contacted form the
		196	outside. This means the node cannot talk to other nodes that also have no
		197	binds, but it can still talk to all "normal" nodes).
170		198
171	Afterwards, the node will bind itself on all endpoints and try to connect	199	If the profile does not specify a binds list, then a default of C<*> is
172	to all additional C<$seednodes> that are specified. Seednodes are optional	200	used.
173	and can be used to quickly bootstrap the node into an existing network.
174		201
175	=item slave nodes	202	Lastly, the seeds list from the profile is passed to the
		203	L<AnyEvent::MP::Global> module, which will then use it to keep
		204	connectivity with at least on of those seed nodes at any point in time.
176		205
177	When the C<$noderef> is the special string C<slave/>, then the node will	206	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	207	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.	208	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		209
193	initialise_node;	210	initialise_node;
194		211
195	Example: become a public node, and try to contact some well-known master	212	Example: become an anonymous node. This form is often used for commandline
196	servers to become part of the network.	213	clients.
197		214
198	initialise_node undef, "master1", "master2";
199
200	Example: become a public node listening on port C<4041>.
201
202	initialise_node 4041;	215	initialise_node "anon/";
203		216
204	Example: become a public node, only visible on localhost port 4044.	217	Example: become a distributed node. If there is no profile of the given
		218	name, or no binds list was specified, resolve C<localhost:4044> and bind
		219	on the resulting addresses.
205		220
206	initialise_node "locahost:4044";	221	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		222
241	=item $SELF	223	=item $SELF
242		224
243	Contains the current port id while executing C<rcv> callbacks or C<psub>	225	Contains the current port id while executing C<rcv> callbacks or C<psub>
244	blocks.	226	blocks.
245		227
246	=item SELF, %SELF, @SELF...	228	=item *SELF, SELF, %SELF, @SELF...
247		229
248	Due to some quirks in how perl exports variables, it is impossible to	230	Due to some quirks in how perl exports variables, it is impossible to
249	just export C<$SELF>, all the symbols called C<SELF> are exported by this	231	just export C<$SELF>, all the symbols named C<SELF> are exported by this
250	module, but only C<$SELF> is currently used.	232	module, but only C<$SELF> is currently used.
251		233
252	=item snd $port, type => @data	234	=item snd $port, type => @data
253		235
254	=item snd $port, @msg	236	=item snd $port, @msg
255		237
256	Send the given message to the given port ID, which can identify either	238	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	239	local or a remote port, and must be a port ID.
258	stringifies a sa port ID (such as a port object :).
259		240
260	While the message can be about anything, it is highly recommended to use a	241	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	242	use a string as first element (a port ID, or some word that indicates a
262	type etc.).	243	request type etc.) and to consist if only simple perl values (scalars,
		244	arrays, hashes) - if you think you need to pass an object, think again.
263		245
264	The message data effectively becomes read-only after a call to this	246	The message data logically becomes read-only after a call to this
265	function: modifying any argument is not allowed and can cause many	247	function: modifying any argument (or values referenced by them) is
266	problems.	248	forbidden, as there can be considerable time between the call to C<snd>
		249	and the time the message is actually being serialised - in fact, it might
		250	never be copied as within the same process it is simply handed to the
		251	receiving port.
267		252
268	The type of data you can transfer depends on the transport protocol: when	253	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	254	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	255	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	256	that Storable can serialise and deserialise is allowed, and for the local
272	node, anything can be passed.	257	node, anything can be passed. Best rely only on the common denominator of
		258	these.
273		259
274	=item $local_port = port	260	=item $local_port = port
275		261
276	Create a new local port object that can be used either as a pattern	262	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"),	263	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		264
280	=item $port = port { my @msg = @_; $finished }	265	=item $local_port = port { my @msg = @_ }
281		266
282	Creates a "miniport", that is, a very lightweight port without any pattern	267	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.	268	creating a port and calling C<rcv $port, $callback> on it.
285		269
286	The block will be called for every message received on the port. When the	270	The block will be called for every message received on the port, with the
287	callback returns a true value its job is considered "done" and the port	271	global variable C<$SELF> set to the port ID. Runtime errors will cause the
288	will be destroyed. Otherwise it will stay alive.	272	port to be C<kil>ed. The message will be passed as-is, no extra argument
		273	(i.e. no port ID) will be passed to the callback.
289		274
290	The message will be passed as-is, no extra argument (i.e. no port id) will	275	If you want to stop/destroy the port, simply C<kil> it:
291	be passed to the callback.
292		276
293	If you need the local port id in the callback, this works nicely:	277	my $port = port {
294		278	my @msg = @_;
295	my $port; $port = port {	279	...
296	snd $otherport, reply => $port;	280	kil $SELF;
297	};	281	};
298		282
299	=cut	283	=cut
300		284
301	sub rcv($@);	285	sub rcv($@);
		286
		287	sub _kilme {
		288	die "received message on port without callback";
		289	}
302		290
303	sub port(;&) {	291	sub port(;&) {
304	my $id = "$UNIQ." . $ID++;	292	my $id = "$UNIQ." . $ID++;
305	my $port = "$NODE#$id";	293	my $port = "$NODE#$id";
306		294
307	if (@_) {	295	rcv $port, shift \|\| \&_kilme;
308	rcv $port, shift;
309	} else {
310	$PORT{$id} = sub { }; # nop
311	}
312		296
313	$port	297	$port
314	}	298	}
315		299
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)	300	=item rcv $local_port, $callback->(@msg)
336		301
337	Replaces the callback on the specified miniport (after converting it to	302	Replaces the default callback on the specified port. There is no way to
338	one if required).	303	remove the default callback: use C<sub { }> to disable it, or better
339		304	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...] => $callback->(@msg), ...
345
346	Register callbacks to be called on matching messages on the given full
347	port (after converting it to one if required) and return the port.
348
349	The callback has to return a true value when its work is done, after
350	which is will be removed, or a false value in which case it will stay
351	registered.
352		305
353	The global C<$SELF> (exported by this module) contains C<$port> while	306	The global C<$SELF> (exported by this module) contains C<$port> while
354	executing the callback.	307	executing the callback. Runtime errors during callback execution will
		308	result in the port being C<kil>ed.
355		309
356	Runtime errors during callback execution will result in the port being	310	The default callback received all messages not matched by a more specific
357	C<kil>ed.	311	C<tag> match.
358		312
359	If the match is an array reference, then it will be matched against the	313	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
360	first elements of the message, otherwise only the first element is being
361	matched.
362		314
363	Any element in the match that is specified as C<_any_> (a function	315	Register (or replace) callbacks to be called on messages starting with the
364	exported by this module) matches any single element of the message.	316	given tag on the given port (and return the port), or unregister it (when
		317	C<$callback> is C<$undef> or missing). There can only be one callback
		318	registered for each tag.
365		319
366	While not required, it is highly recommended that the first matching	320	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	321	element (the tag) has been removed. The callback will use the same
368	also the most efficient match (by far).	322	environment as the default callback (see above).
369		323
370	Example: create a port and bind receivers on it in one go.	324	Example: create a port and bind receivers on it in one go.
371		325
372	my $port = rcv port,	326	my $port = rcv port,
373	msg1 => sub { ...; 0 },	327	msg1 => sub { ... },
374	msg2 => sub { ...; 0 },	328	msg2 => sub { ... },
375	;	329	;
376		330
377	Example: create a port, bind receivers and send it in a message elsewhere	331	Example: create a port, bind receivers and send it in a message elsewhere
378	in one go:	332	in one go:
379		333
380	snd $otherport, reply =>	334	snd $otherport, reply =>
381	rcv port,	335	rcv port,
382	msg1 => sub { ...; 0 },	336	msg1 => sub { ... },
383	...	337	...
384	;	338	;
		339
		340	Example: temporarily register a rcv callback for a tag matching some port
		341	(e.g. for a rpc reply) and unregister it after a message was received.
		342
		343	rcv $port, $otherport => sub {
		344	my @reply = @_;
		345
		346	rcv $SELF, $otherport;
		347	};
385		348
386	=cut	349	=cut
387		350
388	sub rcv($@) {	351	sub rcv($@) {
389	my $port = shift;	352	my $port = shift;
390	my ($noderef, $portid) = split /#/, $port, 2;	353	my ($noderef, $portid) = split /#/, $port, 2;
391		354
392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	355	$NODE{$noderef} == $NODE{""}
393	or Carp::croak "$port: rcv can only be called on local ports, caught";	356	or Carp::croak "$port: rcv can only be called on local ports, caught";
394		357
395	if (@_ == 1) {	358	while (@_) {
		359	if (ref $_[0]) {
		360	if (my $self = $PORT_DATA{$portid}) {
		361	"AnyEvent::MP::Port" eq ref $self
		362	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		363
		364	$self->[2] = shift;
		365	} else {
396	my $cb = shift;	366	my $cb = shift;
397	delete $PORT_DATA{$portid};
398	$PORT{$portid} = sub {	367	$PORT{$portid} = sub {
399	local $SELF = $port;	368	local $SELF = $port;
400	eval {	369	eval { &$cb }; _self_die if $@;
401	&$cb	370	};
402	and kil $port;
403	};	371	}
404	_self_die if $@;	372	} elsif (defined $_[0]) {
405	};
406	} else {
407	my $self = $PORT_DATA{$portid} \|\|= do {	373	my $self = $PORT_DATA{$portid} \|\|= do {
408	my $self = bless {	374	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
409	id => $port,
410	}, "AnyEvent::MP::Port";
411		375
412	$PORT{$portid} = sub {	376	$PORT{$portid} = sub {
413	local $SELF = $port;	377	local $SELF = $port;
414		378
415	eval {
416	for (@{ $self->{rc0}{$_[0]} }) {	379	if (my $cb = $self->[1]{$_[0]}) {
417	$_ && &{$_->[0]}	380	shift;
418	&& undef $_;	381	eval { &$cb }; _self_die if $@;
419	}	382	} else {
420
421	for (@{ $self->{rcv}{$_[0]} }) {
422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
423	&& &{$_->[0]}	383	&{ $self->[0] };
424	&& undef $_;
425	}
426
427	for (@{ $self->{any} }) {
428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
429	&& &{$_->[0]}
430	&& undef $_;
431	}	384	}
432	};	385	};
433	_self_die if $@;	386
		387	$self
434	};	388	};
435		389
436	$self
437	};
438
439	"AnyEvent::MP::Port" eq ref $self	390	"AnyEvent::MP::Port" eq ref $self
440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	391	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
441		392
442	while (@_) {
443	my ($match, $cb) = splice @_, 0, 2;	393	my ($tag, $cb) = splice @_, 0, 2;
444		394
445	if (!ref $match) {	395	if (defined $cb) {
446	push @{ $self->{rc0}{$match} }, [$cb];	396	$self->[1]{$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 {	397	} else {
453	push @{ $self->{any} }, [$cb, $match];	398	delete $self->[1]{$tag};
454	}	399	}
455	}	400	}
456	}	401	}
457		402
458	$port	403	$port
…		…
494	$res	439	$res
495	}	440	}
496	}	441	}
497	}	442	}
498		443
499	=item $guard = mon $port, $cb->(@reason)	444	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
500		445
501	=item $guard = mon $port, $rcvport	446	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
502		447
503	=item $guard = mon $port	448	=item $guard = mon $port # kill $SELF when $port dies
504		449
505	=item $guard = mon $port, $rcvport, @msg	450	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
506		451
507	Monitor the given port and do something when the port is killed or	452	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	453	messages to it were lost, and optionally return a guard that can be used
509	to stop monitoring again.	454	to stop monitoring again.
510		455
511	C<mon> effectively guarantees that, in the absence of hardware failures,	456	C<mon> effectively guarantees that, in the absence of hardware failures,
512	that after starting the monitor, either all messages sent to the port	457	after starting the monitor, either all messages sent to the port will
513	will arrive, or the monitoring action will be invoked after possible	458	arrive, or the monitoring action will be invoked after possible message
514	message loss has been detected. No messages will be lost "in between"	459	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	460	the first lost message no further messages will be received by the
516	port). After the monitoring action was invoked, further messages might get	461	port). After the monitoring action was invoked, further messages might get
517	delivered again.	462	delivered again.
		463
		464	Note that monitoring-actions are one-shot: once messages are lost (and a
		465	monitoring alert was raised), they are removed and will not trigger again.
518		466
519	In the first form (callback), the callback is simply called with any	467	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	468	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	469	"normally"). Note also that I<< the callback B<must> never die >>, so use
522	C<eval> if unsure.	470	C<eval> if unsure.
…		…
584	is killed, the references will be freed.	532	is killed, the references will be freed.
585		533
586	Optionally returns a guard that will stop the monitoring.	534	Optionally returns a guard that will stop the monitoring.
587		535
588	This function is useful when you create e.g. timers or other watchers and	536	This function is useful when you create e.g. timers or other watchers and
589	want to free them when the port gets killed:	537	want to free them when the port gets killed (note the use of C<psub>):
590		538
591	$port->rcv (start => sub {	539	$port->rcv (start => sub {
592	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	540	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
593	undef $timer if 0.9 < rand;	541	undef $timer if 0.9 < rand;
594	});	542	});
595	});	543	});
596		544
597	=cut	545	=cut
…		…
606		554
607	=item kil $port[, @reason]	555	=item kil $port[, @reason]
608		556
609	Kill the specified port with the given C<@reason>.	557	Kill the specified port with the given C<@reason>.
610		558
611	If no C<@reason> is specified, then the port is killed "normally" (linked	559	If no C<@reason> is specified, then the port is killed "normally" (ports
612	ports will not be kileld, or even notified).	560	monitoring other ports will not necessarily die because a port dies
		561	"normally").
613		562
614	Otherwise, linked ports get killed with the same reason (second form of	563	Otherwise, linked ports get killed with the same reason (second form of
615	C<mon>, see below).	564	C<mon>, see above).
616		565
617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	566	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
618	will be reported as reason C<< die => $@ >>.	567	will be reported as reason C<< die => $@ >>.
619		568
620	Transport/communication errors are reported as C<< transport_error =>	569	Transport/communication errors are reported as C<< transport_error =>
…		…
625	=item $port = spawn $node, $initfunc[, @initdata]	574	=item $port = spawn $node, $initfunc[, @initdata]
626		575
627	Creates a port on the node C<$node> (which can also be a port ID, in which	576	Creates a port on the node C<$node> (which can also be a port ID, in which
628	case it's the node where that port resides).	577	case it's the node where that port resides).
629		578
630	The port ID of the newly created port is return immediately, and it is	579	The port ID of the newly created port is returned immediately, and it is
631	permissible to immediately start sending messages or monitor the port.	580	possible to immediately start sending messages or to monitor the port.
632		581
633	After the port has been created, the init function is	582	After the port has been created, the init function is called on the remote
634	called. This function must be a fully-qualified function name	583	node, in the same context as a C<rcv> callback. This function must be a
635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	584	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
636	program, use C<::name>.	585	specify a function in the main program, use C<::name>.
637		586
638	If the function doesn't exist, then the node tries to C<require>	587	If the function doesn't exist, then the node tries to C<require>
639	the package, then the package above the package and so on (e.g.	588	the package, then the package above the package and so on (e.g.
640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	589	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
641	exists or it runs out of package names.	590	exists or it runs out of package names.
642		591
643	The init function is then called with the newly-created port as context	592	The init function is then called with the newly-created port as context
644	object (C<$SELF>) and the C<@initdata> values as arguments.	593	object (C<$SELF>) and the C<@initdata> values as arguments.
645		594
646	A common idiom is to pass your own port, monitor the spawned port, and	595	A common idiom is to pass a local port, immediately monitor the spawned
647	in the init function, monitor the original port. This two-way monitoring	596	port, and in the remote init function, immediately monitor the passed
648	ensures that both ports get cleaned up when there is a problem.	597	local port. This two-way monitoring ensures that both ports get cleaned up
		598	when there is a problem.
649		599
650	Example: spawn a chat server port on C<$othernode>.	600	Example: spawn a chat server port on C<$othernode>.
651		601
652	# this node, executed from within a port context:	602	# this node, executed from within a port context:
653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	603	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
683	my $id = "$RUNIQ." . $ID++;	633	my $id = "$RUNIQ." . $ID++;
684		634
685	$_[0] =~ /::/	635	$_[0] =~ /::/
686	or Carp::croak "spawn init function must be a fully-qualified name, caught";	636	or Carp::croak "spawn init function must be a fully-qualified name, caught";
687		637
688	($NODE{$noderef} \|\| add_node $noderef)	638	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
690		639
691	"$noderef#$id"	640	"$noderef#$id"
692	}	641	}
693		642
694	=back	643	=item after $timeout, @msg
695		644
696	=head1 NODE MESSAGES	645	=item after $timeout, $callback
697		646
698	Nodes understand the following messages sent to them. Many of them take	647	Either sends the given message, or call the given callback, after the
699	arguments called C<@reply>, which will simply be used to compose a reply	648	specified number of seconds.
700	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
701	the remaining arguments are simply the message data.
702		649
703	While other messages exist, they are not public and subject to change.	650	This is simply a utility function that comes in handy at times - the
		651	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		652	so it may go away in the future.
704		653
705	=over 4
706
707	=cut	654	=cut
708		655
709	=item lookup => $name, @reply	656	sub after($@) {
		657	my ($timeout, @action) = @_;
710		658
711	Replies with the port ID of the specified well-known port, or C<undef>.	659	my $t; $t = AE::timer $timeout, 0, sub {
712		660	undef $t;
713	=item devnull => ...	661	ref $action[0]
714		662	? $action[0]()
715	Generic data sink/CPU heat conversion.	663	: snd @action;
716		664	};
717	=item relay => $port, @msg	665	}
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		666
740	=back	667	=back
741		668
742	=head1 AnyEvent::MP vs. Distributed Erlang	669	=head1 AnyEvent::MP vs. Distributed Erlang
743		670
…		…
753		680
754	Despite the similarities, there are also some important differences:	681	Despite the similarities, there are also some important differences:
755		682
756	=over 4	683	=over 4
757		684
758	=item * Node references contain the recipe on how to contact them.	685	=item * Node IDs are arbitrary strings in AEMP.
759		686
760	Erlang relies on special naming and DNS to work everywhere in the	687	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	688	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
762	convenience functionality.	689	configuraiton or DNS), but will otherwise discover other odes itself.
763		690
764	This means that AEMP requires a less tightly controlled environment at the	691	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
765	cost of longer node references and a slightly higher management overhead.	692	uses "local ports are like remote ports".
		693
		694	The failure modes for local ports are quite different (runtime errors
		695	only) then for remote ports - when a local port dies, you I<know> it dies,
		696	when a connection to another node dies, you know nothing about the other
		697	port.
		698
		699	Erlang pretends remote ports are as reliable as local ports, even when
		700	they are not.
		701
		702	AEMP encourages a "treat remote ports differently" philosophy, with local
		703	ports being the special case/exception, where transport errors cannot
		704	occur.
766		705
767	=item * Erlang uses processes and a mailbox, AEMP does not queue.	706	=item * Erlang uses processes and a mailbox, AEMP does not queue.
768		707
769	Erlang uses processes that selctively receive messages, and therefore	708	Erlang uses processes that selectively receive messages, and therefore
770	needs a queue. AEMP is event based, queuing messages would serve no useful	709	needs a queue. AEMP is event based, queuing messages would serve no
771	purpose.	710	useful purpose. For the same reason the pattern-matching abilities of
		711	AnyEvent::MP are more limited, as there is little need to be able to
		712	filter messages without dequeing them.
772		713
773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	714	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
774		715
775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	716	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
776		717
777	Sending messages in Erlang is synchronous and blocks the process. AEMP	718	Sending messages in Erlang is synchronous and blocks the process (and
778	sends are immediate, connection establishment is handled in the	719	so does not need a queue that can overflow). AEMP sends are immediate,
779	background.	720	connection establishment is handled in the background.
780		721
781	=item * Erlang can silently lose messages, AEMP cannot.	722	=item * Erlang suffers from silent message loss, AEMP does not.
782		723
783	Erlang makes few guarantees on messages delivery - messages can get lost	724	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,	725	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).	726	and c, and the other side only receives messages a and c).
786		727
787	AEMP guarantees correct ordering, and the guarantee that there are no	728	AEMP guarantees correct ordering, and the guarantee that after one message
788	holes in the message sequence.	729	is lost, all following ones sent to the same port are lost as well, until
789		730	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	731	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		732
801	=item * Erlang can send messages to the wrong port, AEMP does not.	733	=item * Erlang can send messages to the wrong port, AEMP does not.
802		734
803	In Erlang it is quite possible that a node that restarts reuses a process	735	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	736	known to other nodes for a completely different process, causing messages
805	messages destined for that process to end up in an unrelated process.	737	destined for that process to end up in an unrelated process.
806		738
807	AEMP never reuses port IDs, so old messages or old port IDs floating	739	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.	740	around in the network will not be sent to an unrelated port.
809		741
810	=item * Erlang uses unprotected connections, AEMP uses secure	742	=item * Erlang uses unprotected connections, AEMP uses secure
811	authentication and can use TLS.	743	authentication and can use TLS.
812		744
813	AEMP can use a proven protocol - SSL/TLS - to protect connections and	745	AEMP can use a proven protocol - TLS - to protect connections and
814	securely authenticate nodes.	746	securely authenticate nodes.
815		747
816	=item * The AEMP protocol is optimised for both text-based and binary	748	=item * The AEMP protocol is optimised for both text-based and binary
817	communications.	749	communications.
818		750
819	The AEMP protocol, unlike the Erlang protocol, supports both	751	The AEMP protocol, unlike the Erlang protocol, supports both programming
820	language-independent text-only protocols (good for debugging) and binary,	752	language independent text-only protocols (good for debugging) and binary,
821	language-specific serialisers (e.g. Storable).	753	language-specific serialisers (e.g. Storable). By default, unless TLS is
		754	used, the protocol is actually completely text-based.
822		755
823	It has also been carefully designed to be implementable in other languages	756	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	757	with a minimum of work while gracefully degrading functionality to make the
825	protocol simple.	758	protocol simple.
826		759
827	=item * AEMP has more flexible monitoring options than Erlang.	760	=item * AEMP has more flexible monitoring options than Erlang.
828		761
829	In Erlang, you can chose to receive I<all> exit signals as messages	762	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	765	Erlang, as one can choose between automatic kill, exit message or callback
833	on a per-process basis.	766	on a per-process basis.
834		767
835	=item * Erlang tries to hide remote/local connections, AEMP does not.	768	=item * Erlang tries to hide remote/local connections, AEMP does not.
836		769
837	Monitoring in Erlang is not an indicator of process death/crashes,	770	Monitoring in Erlang is not an indicator of process death/crashes, in the
838	as linking is (except linking is unreliable in Erlang).	771	same way as linking is (except linking is unreliable in Erlang).
839		772
840	In AEMP, you don't "look up" registered port names or send to named ports	773	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	774	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	775	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	776	remote port. Since both monitors are local to the node, they are much more
844	more reliable.	777	reliable (no need for C<spawn_link>).
845		778
846	This also saves round-trips and avoids sending messages to the wrong port	779	This also saves round-trips and avoids sending messages to the wrong port
847	(hard to do in Erlang).	780	(hard to do in Erlang).
848		781
849	=back	782	=back
850		783
		784	=head1 RATIONALE
		785
		786	=over 4
		787
		788	=item Why strings for port and node IDs, why not objects?
		789
		790	We considered "objects", but found that the actual number of methods
		791	that can be called are quite low. Since port and node IDs travel over
		792	the network frequently, the serialising/deserialising would add lots of
		793	overhead, as well as having to keep a proxy object everywhere.
		794
		795	Strings can easily be printed, easily serialised etc. and need no special
		796	procedures to be "valid".
		797
		798	And as a result, a miniport consists of a single closure stored in a
		799	global hash - it can't become much cheaper.
		800
		801	=item Why favour JSON, why not a real serialising format such as Storable?
		802
		803	In fact, any AnyEvent::MP node will happily accept Storable as framing
		804	format, but currently there is no way to make a node use Storable by
		805	default (although all nodes will accept it).
		806
		807	The default framing protocol is JSON because a) JSON::XS is many times
		808	faster for small messages and b) most importantly, after years of
		809	experience we found that object serialisation is causing more problems
		810	than it solves: Just like function calls, objects simply do not travel
		811	easily over the network, mostly because they will always be a copy, so you
		812	always have to re-think your design.
		813
		814	Keeping your messages simple, concentrating on data structures rather than
		815	objects, will keep your messages clean, tidy and efficient.
		816
		817	=back
		818
851	=head1 SEE ALSO	819	=head1 SEE ALSO
		820
		821	L<AnyEvent::MP::Intro> - a gentle introduction.
		822
		823	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		824
		825	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		826	your applications.
852		827
853	L<AnyEvent>.	828	L<AnyEvent>.
854		829
855	=head1 AUTHOR	830	=head1 AUTHOR
856		831

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Revision 1.71 by root, Sun Aug 30 19:52:56 2009 UTC