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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs.
Revision 1.74 by root, Mon Aug 31 11:11:27 2009 UTC

…		…
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
13	$SELF # receiving/own port id in rcv callbacks	13	$SELF # receiving/own port id in rcv callbacks
14		14
15	# initialise the node so it can send/receive messages	15	# initialise the node so it can send/receive messages
16	initialise_node; # -OR-	16	configure;
17	initialise_node "localhost:4040"; # -OR-
18	initialise_node "slave/", "localhost:4040"
19		17
20	# ports are message endpoints	18	# ports are message endpoints
21		19
22	# sending messages	20	# sending messages
23	snd $port, type => data...;	21	snd $port, type => data...;
24	snd $port, @msg;	22	snd $port, @msg;
25	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
26		24
27	# creating/using miniports	25	# creating/using ports, the simple way
28	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_ };
29		27
30	# creating/using full ports	28	# creating/using ports, tagged message matching
31	my $port = port;	29	my $port = port;
32	rcv $port, smartmatch => $cb->(@msg);
33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong" };
34	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n" };
35
36	# more, smarter, matches (_any_ is exported by this module)
37	rcv $port, [child_died => $pid] => sub { ...
38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
39		32
40	# create a port on another node	33	# create a port on another node
41	my $port = spawn $node, $initfunc, @initdata;	34	my $port = spawn $node, $initfunc, @initdata;
42		35
43	# monitoring	36	# monitoring
…		…
45	mon $port, $otherport # kill otherport on abnormal death	38	mon $port, $otherport # kill otherport on abnormal death
46	mon $port, $otherport, @msg # send message on death	39	mon $port, $otherport, @msg # send message on death
47		40
48	=head1 CURRENT STATUS	41	=head1 CURRENT STATUS
49		42
		43	bin/aemp - stable.
50	AnyEvent::MP - stable API, should work	44	AnyEvent::MP - stable API, should work.
51	AnyEvent::MP::Intro - outdated	45	AnyEvent::MP::Intro - uptodate, but incomplete.
52	AnyEvent::MP::Kernel - WIP
53	AnyEvent::MP::Transport - mostly stable	46	AnyEvent::MP::Kernel - mostly stable.
		47	AnyEvent::MP::Global - stable API, protocol not yet final.
54		48
55	stay tuned.	49	stay tuned.
56		50
57	=head1 DESCRIPTION	51	=head1 DESCRIPTION
58		52
59	This module (-family) implements a simple message passing framework.	53	This module (-family) implements a simple message passing framework.
60		54
61	Despite its simplicity, you can securely message other processes running	55	Despite its simplicity, you can securely message other processes running
62	on the same or other hosts.	56	on the same or other hosts, and you can supervise entities remotely.
63		57
64	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>
65	manual page.	59	manual page and the examples under F<eg/>.
66		60
67	At the moment, this module family is severly broken and underdocumented,	61	At the moment, this module family is a bit underdocumented.
68	so do not use. This was uploaded mainly to reserve the CPAN namespace -
69	stay tuned!
70		62
71	=head1 CONCEPTS	63	=head1 CONCEPTS
72		64
73	=over 4	65	=over 4
74		66
75	=item port	67	=item port
76		68
77	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).
78		70
79	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
80	messages. All C<rcv> handlers will receive messages they match, messages	72	some messages. Messages send to ports will not be queued, regardless of
81	will not be queued.	73	anything was listening for them or not.
82		74
83	=item port id - C<noderef#portname>	75	=item port ID - C<nodeid#portname>
84		76
85	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
86	separator, and a port name (a printable string of unspecified format). An	78	separator, and a port name (a printable string of unspecified format).
87	exception is the the node port, whose ID is identical to its node
88	reference.
89		79
90	=item node	80	=item node
91		81
92	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,
93	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
94	create new ports, among other things.	84	ports.
95		85
96	Nodes are either private (single-process only), slaves (connected to a	86	Nodes are either public (have one or more listening ports) or private
97	master node only) or public nodes (connectable from unrelated nodes).	87	(no listening ports). Private nodes cannot talk to other private nodes
		88	currently.
98		89
99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	90	=item node ID - C<[a-za-Z0-9_\-.:]+>
100		91
101	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
102	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
103	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.
104		96
105	This recipe is simply a comma-separated list of C<address:port> pairs (for	97	=item binds - C<ip:port>
106	TCP/IP, other protocols might look different).
107		98
108	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
109	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.
110		103
111	Before using an unresolved node reference in a message you first have to	104	=item seeds - C<host:port>
112	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.
113		118
114	=back	119	=back
115		120
116	=head1 VARIABLES/FUNCTIONS	121	=head1 VARIABLES/FUNCTIONS
117		122
…		…
132	use base "Exporter";	137	use base "Exporter";
133		138
134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	139	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
135		140
136	our @EXPORT = qw(	141	our @EXPORT = qw(
137	NODE $NODE *SELF node_of _any_	142	NODE $NODE *SELF node_of after
138	resolve_node initialise_node	143	configure
139	snd rcv mon kil reg psub spawn	144	snd rcv mon mon_guard kil reg psub spawn
140	port	145	port
141	);	146	);
142		147
143	our $SELF;	148	our $SELF;
144		149
…		…
148	kil $SELF, die => $msg;	153	kil $SELF, die => $msg;
149	}	154	}
150		155
151	=item $thisnode = NODE / $NODE	156	=item $thisnode = NODE / $NODE
152		157
153	The C<NODE> function returns, and the C<$NODE> variable contains	158	The C<NODE> function returns, and the C<$NODE> variable contains, the node
154	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
155	to C<become_public> or C<become_slave>, after which all local port	160	a call to C<configure>.
156	identifiers become invalid.
157		161
158	=item $noderef = node_of $port	162	=item $nodeid = node_of $port
159		163
160	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.
161		165
162	=item initialise_node $noderef, $seednode, $seednode...	166	=item configure key => value...
163		167
164	=item initialise_node "slave/", $master, $master...
165
166	Before a node can talk to other nodes on the network it has to initialise	168	Before a node can talk to other nodes on the network (i.e. enter
167	itself - the minimum a node needs to know is it's own name, and optionally	169	"distributed mode") it has to configure itself - the minimum a node needs
168	it should know the noderefs of some other nodes in the network.	170	to know is its own name, and optionally it should know the addresses of
		171	some other nodes in the network to discover other nodes.
169		172
170	This function initialises a node - it must be called exactly once (or	173	This function configures a node - it must be called exactly once (or
171	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
172		175
173	All arguments are noderefs, which can be either resolved or unresolved.
174
175	There are two types of networked nodes, public nodes and slave nodes:
176
177	=over 4	176	=over 4
178		177
179	=item public nodes	178	=item step 1, gathering configuration from profiles
180		179
181	For public nodes, C<$noderef> must either be a (possibly unresolved)	180	The function first looks up a profile in the aemp configuration (see the
182	noderef, in which case it will be resolved, or C<undef> (or missing), in	181	L<aemp> commandline utility). The profile name can be specified via the
183	which case the noderef will be guessed.	182	named C<profile> parameter. If it is missing, then the nodename (F<uname
		183	-n>) will be used as profile name.
184		184
185	Afterwards, the node will bind itself on all endpoints and try to connect	185	The profile data is then gathered as follows:
186	to all additional C<$seednodes> that are specified. Seednodes are optional
187	and can be used to quickly bootstrap the node into an existing network.
188		186
189	=item slave nodes	187	First, all remaining key => value pairs (all of which are conviniently
		188	undocumented at the moment) will be interpreted as configuration
		189	data. Then they will be overwritten by any values specified in the global
		190	default configuration (see the F<aemp> utility), then the chain of
		191	profiles chosen by the profile name (and any C<parent> attributes).
190		192
191	When the C<$noderef> is the special string C<slave/>, then the node will	193	That means that the values specified in the profile have highest priority
192	become a slave node. Slave nodes cannot be contacted from outside and will	194	and the values specified directly via C<configure> have lowest priority,
193	route most of their traffic to the master node that they attach to.	195	and can only be used to specify defaults.
194		196
195	At least one additional noderef is required: The node will try to connect	197	If the profile specifies a node ID, then this will become the node ID of
196	to all of them and will become a slave attached to the first node it can	198	this process. If not, then the profile name will be used as node ID. The
197	successfully connect to.	199	special node ID of C<anon/> will be replaced by a random node ID.
		200
		201	=item step 2, bind listener sockets
		202
		203	The next step is to look up the binds in the profile, followed by binding
		204	aemp protocol listeners on all binds specified (it is possible and valid
		205	to have no binds, meaning that the node cannot be contacted form the
		206	outside. This means the node cannot talk to other nodes that also have no
		207	binds, but it can still talk to all "normal" nodes).
		208
		209	If the profile does not specify a binds list, then a default of C<*> is
		210	used, meaning the node will bind on a dynamically-assigned port on every
		211	local IP address it finds.
		212
		213	=item step 3, connect to seed nodes
		214
		215	As the last step, the seeds list from the profile is passed to the
		216	L<AnyEvent::MP::Global> module, which will then use it to keep
		217	connectivity with at least one node at any point in time.
198		218
199	=back	219	=back
200		220
201	This function will block until all nodes have been resolved and, for slave	221	Example: become a distributed node using the locla node name as profile.
202	nodes, until it has successfully established a connection to a master	222	This should be the most common form of invocation for "daemon"-type nodes.
203	server.
204		223
205	Example: become a public node listening on the default node.	224	configure
206		225
207	initialise_node;	226	Example: become an anonymous node. This form is often used for commandline
		227	clients.
208		228
209	Example: become a public node, and try to contact some well-known master	229	configure nodeid => "anon/";
210	servers to become part of the network.
211		230
212	initialise_node undef, "master1", "master2";	231	Example: configure a node using a profile called seed, which si suitable
		232	for a seed node as it binds on all local addresses on a fixed port (4040,
		233	customary for aemp).
213		234
214	Example: become a public node listening on port C<4041>.	235	# use the aemp commandline utility
		236	# aemp profile seed nodeid anon/ binds '*:4040'
215		237
216	initialise_node 4041;	238	# then use it
		239	configure profile => "seed";
217		240
218	Example: become a public node, only visible on localhost port 4044.	241	# or simply use aemp from the shell again:
		242	# aemp run profile seed
219		243
220	initialise_node "locahost:4044";	244	# or provide a nicer-to-remember nodeid
221		245	# aemp run profile seed nodeid "$(hostname)"
222	Example: become a slave node to any of the specified master servers.
223
224	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
225
226	=item $cv = resolve_node $noderef
227
228	Takes an unresolved node reference that may contain hostnames and
229	abbreviated IDs, resolves all of them and returns a resolved node
230	reference.
231
232	In addition to C<address:port> pairs allowed in resolved noderefs, the
233	following forms are supported:
234
235	=over 4
236
237	=item the empty string
238
239	An empty-string component gets resolved as if the default port (4040) was
240	specified.
241
242	=item naked port numbers (e.g. C<1234>)
243
244	These are resolved by prepending the local nodename and a colon, to be
245	further resolved.
246
247	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
248
249	These are resolved by using AnyEvent::DNS to resolve them, optionally
250	looking up SRV records for the C<aemp=4040> port, if no port was
251	specified.
252
253	=back
254		246
255	=item $SELF	247	=item $SELF
256		248
257	Contains the current port id while executing C<rcv> callbacks or C<psub>	249	Contains the current port id while executing C<rcv> callbacks or C<psub>
258	blocks.	250	blocks.
259		251
260	=item SELF, %SELF, @SELF...	252	=item *SELF, SELF, %SELF, @SELF...
261		253
262	Due to some quirks in how perl exports variables, it is impossible to	254	Due to some quirks in how perl exports variables, it is impossible to
263	just export C<$SELF>, all the symbols called C<SELF> are exported by this	255	just export C<$SELF>, all the symbols named C<SELF> are exported by this
264	module, but only C<$SELF> is currently used.	256	module, but only C<$SELF> is currently used.
265		257
266	=item snd $port, type => @data	258	=item snd $port, type => @data
267		259
268	=item snd $port, @msg	260	=item snd $port, @msg
269		261
270	Send the given message to the given port ID, which can identify either	262	Send the given message to the given port, which can identify either a
271	a local or a remote port, and can be either a string or soemthignt hat	263	local or a remote port, and must be a port ID.
272	stringifies a sa port ID (such as a port object :).
273		264
274	While the message can be about anything, it is highly recommended to use a	265	While the message can be almost anything, it is highly recommended to
275	string as first element (a portid, or some word that indicates a request	266	use a string as first element (a port ID, or some word that indicates a
276	type etc.).	267	request type etc.) and to consist if only simple perl values (scalars,
		268	arrays, hashes) - if you think you need to pass an object, think again.
277		269
278	The message data effectively becomes read-only after a call to this	270	The message data logically becomes read-only after a call to this
279	function: modifying any argument is not allowed and can cause many	271	function: modifying any argument (or values referenced by them) is
280	problems.	272	forbidden, as there can be considerable time between the call to C<snd>
		273	and the time the message is actually being serialised - in fact, it might
		274	never be copied as within the same process it is simply handed to the
		275	receiving port.
281		276
282	The type of data you can transfer depends on the transport protocol: when	277	The type of data you can transfer depends on the transport protocol: when
283	JSON is used, then only strings, numbers and arrays and hashes consisting	278	JSON is used, then only strings, numbers and arrays and hashes consisting
284	of those are allowed (no objects). When Storable is used, then anything	279	of those are allowed (no objects). When Storable is used, then anything
285	that Storable can serialise and deserialise is allowed, and for the local	280	that Storable can serialise and deserialise is allowed, and for the local
286	node, anything can be passed.	281	node, anything can be passed. Best rely only on the common denominator of
		282	these.
287		283
288	=item $local_port = port	284	=item $local_port = port
289		285
290	Create a new local port object that can be used either as a pattern	286	Create a new local port object and returns its port ID. Initially it has
291	matching port ("full port") or a single-callback port ("miniport"),	287	no callbacks set and will throw an error when it receives messages.
292	depending on how C<rcv> callbacks are bound to the object.
293		288
294	=item $port = port { my @msg = @_; $finished }	289	=item $local_port = port { my @msg = @_ }
295		290
296	Creates a "miniport", that is, a very lightweight port without any pattern	291	Creates a new local port, and returns its ID. Semantically the same as
297	matching behind it, and returns its ID. Semantically the same as creating
298	a port and calling C<rcv $port, $callback> on it.	292	creating a port and calling C<rcv $port, $callback> on it.
299		293
300	The block will be called for every message received on the port. When the	294	The block will be called for every message received on the port, with the
301	callback returns a true value its job is considered "done" and the port	295	global variable C<$SELF> set to the port ID. Runtime errors will cause the
302	will be destroyed. Otherwise it will stay alive.	296	port to be C<kil>ed. The message will be passed as-is, no extra argument
		297	(i.e. no port ID) will be passed to the callback.
303		298
304	The message will be passed as-is, no extra argument (i.e. no port id) will	299	If you want to stop/destroy the port, simply C<kil> it:
305	be passed to the callback.
306		300
307	If you need the local port id in the callback, this works nicely:	301	my $port = port {
308		302	my @msg = @_;
309	my $port; $port = port {	303	...
310	snd $otherport, reply => $port;	304	kil $SELF;
311	};	305	};
312		306
313	=cut	307	=cut
314		308
315	sub rcv($@);	309	sub rcv($@);
		310
		311	sub _kilme {
		312	die "received message on port without callback";
		313	}
316		314
317	sub port(;&) {	315	sub port(;&) {
318	my $id = "$UNIQ." . $ID++;	316	my $id = "$UNIQ." . $ID++;
319	my $port = "$NODE#$id";	317	my $port = "$NODE#$id";
320		318
321	if (@_) {	319	rcv $port, shift \|\| \&_kilme;
322	rcv $port, shift;
323	} else {
324	$PORT{$id} = sub { }; # nop
325	}
326		320
327	$port	321	$port
328	}	322	}
329		323
330	=item reg $port, $name
331
332	=item reg $name
333
334	Registers the given port (or C<$SELF><<< if missing) under the name
335	C<$name>. If the name already exists it is replaced.
336
337	A port can only be registered under one well known name.
338
339	A port automatically becomes unregistered when it is killed.
340
341	=cut
342
343	sub reg(@) {
344	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
345
346	$REG{$_[0]} = $port;
347	}
348
349	=item rcv $port, $callback->(@msg)	324	=item rcv $local_port, $callback->(@msg)
350		325
351	Replaces the callback on the specified miniport (after converting it to	326	Replaces the default callback on the specified port. There is no way to
352	one if required).	327	remove the default callback: use C<sub { }> to disable it, or better
353		328	C<kil> the port when it is no longer needed.
354	=item rcv $port, tagstring => $callback->(@msg), ...
355
356	=item rcv $port, $smartmatch => $callback->(@msg), ...
357
358	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
359
360	Register callbacks to be called on matching messages on the given full
361	port (after converting it to one if required) and return the port.
362
363	The callback has to return a true value when its work is done, after
364	which is will be removed, or a false value in which case it will stay
365	registered.
366		329
367	The global C<$SELF> (exported by this module) contains C<$port> while	330	The global C<$SELF> (exported by this module) contains C<$port> while
368	executing the callback.	331	executing the callback. Runtime errors during callback execution will
		332	result in the port being C<kil>ed.
369		333
370	Runtime errors during callback execution will result in the port being	334	The default callback received all messages not matched by a more specific
371	C<kil>ed.	335	C<tag> match.
372		336
373	If the match is an array reference, then it will be matched against the	337	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
374	first elements of the message, otherwise only the first element is being
375	matched.
376		338
377	Any element in the match that is specified as C<_any_> (a function	339	Register (or replace) callbacks to be called on messages starting with the
378	exported by this module) matches any single element of the message.	340	given tag on the given port (and return the port), or unregister it (when
		341	C<$callback> is C<$undef> or missing). There can only be one callback
		342	registered for each tag.
379		343
380	While not required, it is highly recommended that the first matching	344	The original message will be passed to the callback, after the first
381	element is a string identifying the message. The one-string-only match is	345	element (the tag) has been removed. The callback will use the same
382	also the most efficient match (by far).	346	environment as the default callback (see above).
383		347
384	Example: create a port and bind receivers on it in one go.	348	Example: create a port and bind receivers on it in one go.
385		349
386	my $port = rcv port,	350	my $port = rcv port,
387	msg1 => sub { ...; 0 },	351	msg1 => sub { ... },
388	msg2 => sub { ...; 0 },	352	msg2 => sub { ... },
389	;	353	;
390		354
391	Example: create a port, bind receivers and send it in a message elsewhere	355	Example: create a port, bind receivers and send it in a message elsewhere
392	in one go:	356	in one go:
393		357
394	snd $otherport, reply =>	358	snd $otherport, reply =>
395	rcv port,	359	rcv port,
396	msg1 => sub { ...; 0 },	360	msg1 => sub { ... },
397	...	361	...
398	;	362	;
		363
		364	Example: temporarily register a rcv callback for a tag matching some port
		365	(e.g. for a rpc reply) and unregister it after a message was received.
		366
		367	rcv $port, $otherport => sub {
		368	my @reply = @_;
		369
		370	rcv $SELF, $otherport;
		371	};
399		372
400	=cut	373	=cut
401		374
402	sub rcv($@) {	375	sub rcv($@) {
403	my $port = shift;	376	my $port = shift;
404	my ($noderef, $portid) = split /#/, $port, 2;	377	my ($noderef, $portid) = split /#/, $port, 2;
405		378
406	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	379	$NODE{$noderef} == $NODE{""}
407	or Carp::croak "$port: rcv can only be called on local ports, caught";	380	or Carp::croak "$port: rcv can only be called on local ports, caught";
408		381
409	if (@_ == 1) {	382	while (@_) {
		383	if (ref $_[0]) {
		384	if (my $self = $PORT_DATA{$portid}) {
		385	"AnyEvent::MP::Port" eq ref $self
		386	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		387
		388	$self->[2] = shift;
		389	} else {
410	my $cb = shift;	390	my $cb = shift;
411	delete $PORT_DATA{$portid};
412	$PORT{$portid} = sub {	391	$PORT{$portid} = sub {
413	local $SELF = $port;	392	local $SELF = $port;
414	eval {	393	eval { &$cb }; _self_die if $@;
415	&$cb	394	};
416	and kil $port;
417	};	395	}
418	_self_die if $@;	396	} elsif (defined $_[0]) {
419	};
420	} else {
421	my $self = $PORT_DATA{$portid} \|\|= do {	397	my $self = $PORT_DATA{$portid} \|\|= do {
422	my $self = bless {	398	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
423	id => $port,
424	}, "AnyEvent::MP::Port";
425		399
426	$PORT{$portid} = sub {	400	$PORT{$portid} = sub {
427	local $SELF = $port;	401	local $SELF = $port;
428		402
429	eval {
430	for (@{ $self->{rc0}{$_[0]} }) {	403	if (my $cb = $self->[1]{$_[0]}) {
431	$_ && &{$_->[0]}	404	shift;
432	&& undef $_;	405	eval { &$cb }; _self_die if $@;
433	}	406	} else {
434
435	for (@{ $self->{rcv}{$_[0]} }) {
436	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
437	&& &{$_->[0]}	407	&{ $self->[0] };
438	&& undef $_;
439	}
440
441	for (@{ $self->{any} }) {
442	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
443	&& &{$_->[0]}
444	&& undef $_;
445	}	408	}
446	};	409	};
447	_self_die if $@;	410
		411	$self
448	};	412	};
449		413
450	$self
451	};
452
453	"AnyEvent::MP::Port" eq ref $self	414	"AnyEvent::MP::Port" eq ref $self
454	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	415	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
455		416
456	while (@_) {
457	my ($match, $cb) = splice @_, 0, 2;	417	my ($tag, $cb) = splice @_, 0, 2;
458		418
459	if (!ref $match) {	419	if (defined $cb) {
460	push @{ $self->{rc0}{$match} }, [$cb];	420	$self->[1]{$tag} = $cb;
461	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
462	my ($type, @match) = @$match;
463	@match
464	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
465	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
466	} else {	421	} else {
467	push @{ $self->{any} }, [$cb, $match];	422	delete $self->[1]{$tag};
468	}	423	}
469	}	424	}
470	}	425	}
471		426
472	$port	427	$port
…		…
508	$res	463	$res
509	}	464	}
510	}	465	}
511	}	466	}
512		467
513	=item $guard = mon $port, $cb->(@reason)	468	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
514		469
515	=item $guard = mon $port, $rcvport	470	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
516		471
517	=item $guard = mon $port	472	=item $guard = mon $port # kill $SELF when $port dies
518		473
519	=item $guard = mon $port, $rcvport, @msg	474	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
520		475
521	Monitor the given port and do something when the port is killed or	476	Monitor the given port and do something when the port is killed or
522	messages to it were lost, and optionally return a guard that can be used	477	messages to it were lost, and optionally return a guard that can be used
523	to stop monitoring again.	478	to stop monitoring again.
524		479
525	C<mon> effectively guarantees that, in the absence of hardware failures,	480	C<mon> effectively guarantees that, in the absence of hardware failures,
526	that after starting the monitor, either all messages sent to the port	481	after starting the monitor, either all messages sent to the port will
527	will arrive, or the monitoring action will be invoked after possible	482	arrive, or the monitoring action will be invoked after possible message
528	message loss has been detected. No messages will be lost "in between"	483	loss has been detected. No messages will be lost "in between" (after
529	(after the first lost message no further messages will be received by the	484	the first lost message no further messages will be received by the
530	port). After the monitoring action was invoked, further messages might get	485	port). After the monitoring action was invoked, further messages might get
531	delivered again.	486	delivered again.
		487
		488	Note that monitoring-actions are one-shot: once messages are lost (and a
		489	monitoring alert was raised), they are removed and will not trigger again.
532		490
533	In the first form (callback), the callback is simply called with any	491	In the first form (callback), the callback is simply called with any
534	number of C<@reason> elements (no @reason means that the port was deleted	492	number of C<@reason> elements (no @reason means that the port was deleted
535	"normally"). Note also that I<< the callback B<must> never die >>, so use	493	"normally"). Note also that I<< the callback B<must> never die >>, so use
536	C<eval> if unsure.	494	C<eval> if unsure.
…		…
598	is killed, the references will be freed.	556	is killed, the references will be freed.
599		557
600	Optionally returns a guard that will stop the monitoring.	558	Optionally returns a guard that will stop the monitoring.
601		559
602	This function is useful when you create e.g. timers or other watchers and	560	This function is useful when you create e.g. timers or other watchers and
603	want to free them when the port gets killed:	561	want to free them when the port gets killed (note the use of C<psub>):
604		562
605	$port->rcv (start => sub {	563	$port->rcv (start => sub {
606	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	564	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
607	undef $timer if 0.9 < rand;	565	undef $timer if 0.9 < rand;
608	});	566	});
609	});	567	});
610		568
611	=cut	569	=cut
…		…
620		578
621	=item kil $port[, @reason]	579	=item kil $port[, @reason]
622		580
623	Kill the specified port with the given C<@reason>.	581	Kill the specified port with the given C<@reason>.
624		582
625	If no C<@reason> is specified, then the port is killed "normally" (linked	583	If no C<@reason> is specified, then the port is killed "normally" (ports
626	ports will not be kileld, or even notified).	584	monitoring other ports will not necessarily die because a port dies
		585	"normally").
627		586
628	Otherwise, linked ports get killed with the same reason (second form of	587	Otherwise, linked ports get killed with the same reason (second form of
629	C<mon>, see below).	588	C<mon>, see above).
630		589
631	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	590	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
632	will be reported as reason C<< die => $@ >>.	591	will be reported as reason C<< die => $@ >>.
633		592
634	Transport/communication errors are reported as C<< transport_error =>	593	Transport/communication errors are reported as C<< transport_error =>
…		…
639	=item $port = spawn $node, $initfunc[, @initdata]	598	=item $port = spawn $node, $initfunc[, @initdata]
640		599
641	Creates a port on the node C<$node> (which can also be a port ID, in which	600	Creates a port on the node C<$node> (which can also be a port ID, in which
642	case it's the node where that port resides).	601	case it's the node where that port resides).
643		602
644	The port ID of the newly created port is return immediately, and it is	603	The port ID of the newly created port is returned immediately, and it is
645	permissible to immediately start sending messages or monitor the port.	604	possible to immediately start sending messages or to monitor the port.
646		605
647	After the port has been created, the init function is	606	After the port has been created, the init function is called on the remote
648	called. This function must be a fully-qualified function name	607	node, in the same context as a C<rcv> callback. This function must be a
649	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	608	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
650	program, use C<::name>.	609	specify a function in the main program, use C<::name>.
651		610
652	If the function doesn't exist, then the node tries to C<require>	611	If the function doesn't exist, then the node tries to C<require>
653	the package, then the package above the package and so on (e.g.	612	the package, then the package above the package and so on (e.g.
654	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	613	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
655	exists or it runs out of package names.	614	exists or it runs out of package names.
656		615
657	The init function is then called with the newly-created port as context	616	The init function is then called with the newly-created port as context
658	object (C<$SELF>) and the C<@initdata> values as arguments.	617	object (C<$SELF>) and the C<@initdata> values as arguments.
659		618
660	A common idiom is to pass your own port, monitor the spawned port, and	619	A common idiom is to pass a local port, immediately monitor the spawned
661	in the init function, monitor the original port. This two-way monitoring	620	port, and in the remote init function, immediately monitor the passed
662	ensures that both ports get cleaned up when there is a problem.	621	local port. This two-way monitoring ensures that both ports get cleaned up
		622	when there is a problem.
663		623
664	Example: spawn a chat server port on C<$othernode>.	624	Example: spawn a chat server port on C<$othernode>.
665		625
666	# this node, executed from within a port context:	626	# this node, executed from within a port context:
667	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	627	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
697	my $id = "$RUNIQ." . $ID++;	657	my $id = "$RUNIQ." . $ID++;
698		658
699	$_[0] =~ /::/	659	$_[0] =~ /::/
700	or Carp::croak "spawn init function must be a fully-qualified name, caught";	660	or Carp::croak "spawn init function must be a fully-qualified name, caught";
701		661
702	($NODE{$noderef} \|\| add_node $noderef)	662	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
703	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
704		663
705	"$noderef#$id"	664	"$noderef#$id"
706	}	665	}
707		666
708	=back	667	=item after $timeout, @msg
709		668
710	=head1 NODE MESSAGES	669	=item after $timeout, $callback
711		670
712	Nodes understand the following messages sent to them. Many of them take	671	Either sends the given message, or call the given callback, after the
713	arguments called C<@reply>, which will simply be used to compose a reply	672	specified number of seconds.
714	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
715	the remaining arguments are simply the message data.
716		673
717	While other messages exist, they are not public and subject to change.	674	This is simply a utility function that comes in handy at times - the
		675	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		676	so it may go away in the future.
718		677
719	=over 4
720
721	=cut	678	=cut
722		679
723	=item lookup => $name, @reply	680	sub after($@) {
		681	my ($timeout, @action) = @_;
724		682
725	Replies with the port ID of the specified well-known port, or C<undef>.	683	my $t; $t = AE::timer $timeout, 0, sub {
726		684	undef $t;
727	=item devnull => ...	685	ref $action[0]
728		686	? $action[0]()
729	Generic data sink/CPU heat conversion.	687	: snd @action;
730		688	};
731	=item relay => $port, @msg	689	}
732
733	Simply forwards the message to the given port.
734
735	=item eval => $string[ @reply]
736
737	Evaluates the given string. If C<@reply> is given, then a message of the
738	form C<@reply, $@, @evalres> is sent.
739
740	Example: crash another node.
741
742	snd $othernode, eval => "exit";
743
744	=item time => @reply
745
746	Replies the the current node time to C<@reply>.
747
748	Example: tell the current node to send the current time to C<$myport> in a
749	C<timereply> message.
750
751	snd $NODE, time => $myport, timereply => 1, 2;
752	# => snd $myport, timereply => 1, 2, <time>
753		690
754	=back	691	=back
755		692
756	=head1 AnyEvent::MP vs. Distributed Erlang	693	=head1 AnyEvent::MP vs. Distributed Erlang
757		694
…		…
767		704
768	Despite the similarities, there are also some important differences:	705	Despite the similarities, there are also some important differences:
769		706
770	=over 4	707	=over 4
771		708
772	=item * Node references contain the recipe on how to contact them.	709	=item * Node IDs are arbitrary strings in AEMP.
773		710
774	Erlang relies on special naming and DNS to work everywhere in the	711	Erlang relies on special naming and DNS to work everywhere in the same
775	same way. AEMP relies on each node knowing it's own address(es), with	712	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
776	convenience functionality.	713	configuraiton or DNS), but will otherwise discover other odes itself.
777		714
778	This means that AEMP requires a less tightly controlled environment at the	715	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
779	cost of longer node references and a slightly higher management overhead.	716	uses "local ports are like remote ports".
		717
		718	The failure modes for local ports are quite different (runtime errors
		719	only) then for remote ports - when a local port dies, you I<know> it dies,
		720	when a connection to another node dies, you know nothing about the other
		721	port.
		722
		723	Erlang pretends remote ports are as reliable as local ports, even when
		724	they are not.
		725
		726	AEMP encourages a "treat remote ports differently" philosophy, with local
		727	ports being the special case/exception, where transport errors cannot
		728	occur.
780		729
781	=item * Erlang uses processes and a mailbox, AEMP does not queue.	730	=item * Erlang uses processes and a mailbox, AEMP does not queue.
782		731
783	Erlang uses processes that selctively receive messages, and therefore	732	Erlang uses processes that selectively receive messages, and therefore
784	needs a queue. AEMP is event based, queuing messages would serve no useful	733	needs a queue. AEMP is event based, queuing messages would serve no
785	purpose.	734	useful purpose. For the same reason the pattern-matching abilities of
		735	AnyEvent::MP are more limited, as there is little need to be able to
		736	filter messages without dequeing them.
786		737
787	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	738	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
788		739
789	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	740	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
790		741
791	Sending messages in Erlang is synchronous and blocks the process. AEMP	742	Sending messages in Erlang is synchronous and blocks the process (and
792	sends are immediate, connection establishment is handled in the	743	so does not need a queue that can overflow). AEMP sends are immediate,
793	background.	744	connection establishment is handled in the background.
794		745
795	=item * Erlang can silently lose messages, AEMP cannot.	746	=item * Erlang suffers from silent message loss, AEMP does not.
796		747
797	Erlang makes few guarantees on messages delivery - messages can get lost	748	Erlang makes few guarantees on messages delivery - messages can get lost
798	without any of the processes realising it (i.e. you send messages a, b,	749	without any of the processes realising it (i.e. you send messages a, b,
799	and c, and the other side only receives messages a and c).	750	and c, and the other side only receives messages a and c).
800		751
801	AEMP guarantees correct ordering, and the guarantee that there are no	752	AEMP guarantees correct ordering, and the guarantee that after one message
802	holes in the message sequence.	753	is lost, all following ones sent to the same port are lost as well, until
803		754	monitoring raises an error, so there are no silent "holes" in the message
804	=item * In Erlang, processes can be declared dead and later be found to be	755	sequence.
805	alive.
806
807	In Erlang it can happen that a monitored process is declared dead and
808	linked processes get killed, but later it turns out that the process is
809	still alive - and can receive messages.
810
811	In AEMP, when port monitoring detects a port as dead, then that port will
812	eventually be killed - it cannot happen that a node detects a port as dead
813	and then later sends messages to it, finding it is still alive.
814		756
815	=item * Erlang can send messages to the wrong port, AEMP does not.	757	=item * Erlang can send messages to the wrong port, AEMP does not.
816		758
817	In Erlang it is quite possible that a node that restarts reuses a process	759	In Erlang it is quite likely that a node that restarts reuses a process ID
818	ID known to other nodes for a completely different process, causing	760	known to other nodes for a completely different process, causing messages
819	messages destined for that process to end up in an unrelated process.	761	destined for that process to end up in an unrelated process.
820		762
821	AEMP never reuses port IDs, so old messages or old port IDs floating	763	AEMP never reuses port IDs, so old messages or old port IDs floating
822	around in the network will not be sent to an unrelated port.	764	around in the network will not be sent to an unrelated port.
823		765
824	=item * Erlang uses unprotected connections, AEMP uses secure	766	=item * Erlang uses unprotected connections, AEMP uses secure
825	authentication and can use TLS.	767	authentication and can use TLS.
826		768
827	AEMP can use a proven protocol - SSL/TLS - to protect connections and	769	AEMP can use a proven protocol - TLS - to protect connections and
828	securely authenticate nodes.	770	securely authenticate nodes.
829		771
830	=item * The AEMP protocol is optimised for both text-based and binary	772	=item * The AEMP protocol is optimised for both text-based and binary
831	communications.	773	communications.
832		774
833	The AEMP protocol, unlike the Erlang protocol, supports both	775	The AEMP protocol, unlike the Erlang protocol, supports both programming
834	language-independent text-only protocols (good for debugging) and binary,	776	language independent text-only protocols (good for debugging) and binary,
835	language-specific serialisers (e.g. Storable).	777	language-specific serialisers (e.g. Storable). By default, unless TLS is
		778	used, the protocol is actually completely text-based.
836		779
837	It has also been carefully designed to be implementable in other languages	780	It has also been carefully designed to be implementable in other languages
838	with a minimum of work while gracefully degrading fucntionality to make the	781	with a minimum of work while gracefully degrading functionality to make the
839	protocol simple.	782	protocol simple.
840		783
841	=item * AEMP has more flexible monitoring options than Erlang.	784	=item * AEMP has more flexible monitoring options than Erlang.
842		785
843	In Erlang, you can chose to receive I<all> exit signals as messages	786	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
846	Erlang, as one can choose between automatic kill, exit message or callback	789	Erlang, as one can choose between automatic kill, exit message or callback
847	on a per-process basis.	790	on a per-process basis.
848		791
849	=item * Erlang tries to hide remote/local connections, AEMP does not.	792	=item * Erlang tries to hide remote/local connections, AEMP does not.
850		793
851	Monitoring in Erlang is not an indicator of process death/crashes,	794	Monitoring in Erlang is not an indicator of process death/crashes, in the
852	as linking is (except linking is unreliable in Erlang).	795	same way as linking is (except linking is unreliable in Erlang).
853		796
854	In AEMP, you don't "look up" registered port names or send to named ports	797	In AEMP, you don't "look up" registered port names or send to named ports
855	that might or might not be persistent. Instead, you normally spawn a port	798	that might or might not be persistent. Instead, you normally spawn a port
856	on the remote node. The init function monitors the you, and you monitor	799	on the remote node. The init function monitors you, and you monitor the
857	the remote port. Since both monitors are local to the node, they are much	800	remote port. Since both monitors are local to the node, they are much more
858	more reliable.	801	reliable (no need for C<spawn_link>).
859		802
860	This also saves round-trips and avoids sending messages to the wrong port	803	This also saves round-trips and avoids sending messages to the wrong port
861	(hard to do in Erlang).	804	(hard to do in Erlang).
862		805
863	=back	806	=back
864		807
865	=head1 RATIONALE	808	=head1 RATIONALE
866		809
867	=over 4	810	=over 4
868		811
869	=item Why strings for ports and noderefs, why not objects?	812	=item Why strings for port and node IDs, why not objects?
870		813
871	We considered "objects", but found that the actual number of methods	814	We considered "objects", but found that the actual number of methods
872	thatc an be called are very low. Since port IDs and noderefs travel over	815	that can be called are quite low. Since port and node IDs travel over
873	the network frequently, the serialising/deserialising would add lots of	816	the network frequently, the serialising/deserialising would add lots of
874	overhead, as well as having to keep a proxy object.	817	overhead, as well as having to keep a proxy object everywhere.
875		818
876	Strings can easily be printed, easily serialised etc. and need no special	819	Strings can easily be printed, easily serialised etc. and need no special
877	procedures to be "valid".	820	procedures to be "valid".
878		821
879	And a a miniport consists of a single closure stored in a global hash - it	822	And as a result, a miniport consists of a single closure stored in a
880	can't become much cheaper.	823	global hash - it can't become much cheaper.
881		824
882	=item Why favour JSON, why not real serialising format such as Storable?	825	=item Why favour JSON, why not a real serialising format such as Storable?
883		826
884	In fact, any AnyEvent::MP node will happily accept Storable as framing	827	In fact, any AnyEvent::MP node will happily accept Storable as framing
885	format, but currently there is no way to make a node use Storable by	828	format, but currently there is no way to make a node use Storable by
886	default.	829	default (although all nodes will accept it).
887		830
888	The default framing protocol is JSON because a) JSON::XS is many times	831	The default framing protocol is JSON because a) JSON::XS is many times
889	faster for small messages and b) most importantly, after years of	832	faster for small messages and b) most importantly, after years of
890	experience we found that object serialisation is causing more problems	833	experience we found that object serialisation is causing more problems
891	than it gains: Just like function calls, objects simply do not travel	834	than it solves: Just like function calls, objects simply do not travel
892	easily over the network, mostly because they will always be a copy, so you	835	easily over the network, mostly because they will always be a copy, so you
893	always have to re-think your design.	836	always have to re-think your design.
894		837
895	Keeping your messages simple, concentrating on data structures rather than	838	Keeping your messages simple, concentrating on data structures rather than
896	objects, will keep your messages clean, tidy and efficient.	839	objects, will keep your messages clean, tidy and efficient.
897		840
898	=back	841	=back
899		842
900	=head1 SEE ALSO	843	=head1 SEE ALSO
901		844
		845	L<AnyEvent::MP::Intro> - a gentle introduction.
		846
		847	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		848
		849	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		850	your applications.
		851
902	L<AnyEvent>.	852	L<AnyEvent>.
903		853
904	=head1 AUTHOR	854	=head1 AUTHOR
905		855
906	Marc Lehmann <schmorp@schmorp.de>	856	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs. Revision 1.74 by root, Mon Aug 31 11:11:27 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs.
Revision 1.74 by root, Mon Aug 31 11:11:27 2009 UTC