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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC

…		…
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
13	$SELF # receiving/own port id in rcv callbacks	13	$SELF # receiving/own port id in rcv callbacks
14		14
15	# initialise the node so it can send/receive messages	15	# initialise the node so it can send/receive messages
16	initialise_node; # -OR-	16	initialise_node;
17	initialise_node "localhost:4040"; # -OR-
18	initialise_node "slave/", "localhost:4040"
19		17
20	# ports are message endpoints	18	# ports are message endpoints
21		19
22	# sending messages	20	# sending messages
23	snd $port, type => data...;	21	snd $port, type => data...;
24	snd $port, @msg;	22	snd $port, @msg;
25	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
26		24
27	# creating/using miniports	25	# creating/using ports, the simple way
28	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
29		27
30	# creating/using full ports	28	# creating/using ports, tagged message matching
31	my $port = port;	29	my $port = port;
32	rcv $port, smartmatch => $cb->(@msg);
33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
34	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n"; 0 };
35
36	# more, smarter, matches (_any_ is exported by this module)
37	rcv $port, [child_died => $pid] => sub { ...
38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
39		32
40	# create a port on another node	33	# create a port on another node
41	my $port = spawn $node, $initfunc, @initdata;	34	my $port = spawn $node, $initfunc, @initdata;
42		35
43	# monitoring	36	# monitoring
…		…
47		40
48	=head1 CURRENT STATUS	41	=head1 CURRENT STATUS
49		42
50	AnyEvent::MP - stable API, should work	43	AnyEvent::MP - stable API, should work
51	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - outdated
52	AnyEvent::MP::Kernel - WIP
53	AnyEvent::MP::Transport - mostly stable	45	AnyEvent::MP::Kernel - mostly stable
		46	AnyEvent::MP::Global - mostly stable
		47	AnyEvent::MP::Node - mostly stable, but internal anyways
		48	AnyEvent::MP::Transport - mostly stable, but internal anyways
54		49
55	stay tuned.	50	stay tuned.
56		51
57	=head1 DESCRIPTION	52	=head1 DESCRIPTION
58		53
59	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
60		55
61	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
62	on the same or other hosts.	57	on the same or other hosts, and you can supervise entities remotely.
63		58
64	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
65	manual page.	60	manual page and the examples under F<eg/>.
66		61
67	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is a bit underdocumented.
68	so do not use. This was uploaded mainly to reserve the CPAN namespace -
69	stay tuned!
70		63
71	=head1 CONCEPTS	64	=head1 CONCEPTS
72		65
73	=over 4	66	=over 4
74		67
75	=item port	68	=item port
76		69
77	A port is something you can send messages to (with the C<snd> function).	70	A port is something you can send messages to (with the C<snd> function).
78		71
79	Some ports allow you to register C<rcv> handlers that can match specific	72	Ports allow you to register C<rcv> handlers that can match all or just
80	messages. All C<rcv> handlers will receive messages they match, messages	73	some messages. Messages send to ports will not be queued, regardless of
81	will not be queued.	74	anything was listening for them or not.
82		75
83	=item port id - C<noderef#portname>	76	=item port ID - C<nodeid#portname>
84		77
85	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	78	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
86	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format).
87	exception is the the node port, whose ID is identical to its node
88	reference.
89		80
90	=item node	81	=item node
91		82
92	A node is a single process containing at least one port - the node	83	A node is a single process containing at least one port - the node port,
93	port. You can send messages to node ports to find existing ports or to	84	which enables nodes to manage each other remotely, and to create new
94	create new ports, among other things.	85	ports.
95		86
96	Nodes are either private (single-process only), slaves (connected to a	87	Nodes are either public (have one or more listening ports) or private
97	master node only) or public nodes (connectable from unrelated nodes).	88	(no listening ports). Private nodes cannot talk to other private nodes
		89	currently.
98		90
99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	91	=item node ID - C<[a-za-Z0-9_\-.:]+>
100		92
101	A node reference is a string that either simply identifies the node (for	93	A node ID is a string that uniquely identifies the node within a
102	private and slave nodes), or contains a recipe on how to reach a given	94	network. Depending on the configuration used, node IDs can look like a
103	node (for public nodes).	95	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		96	doesn't interpret node IDs in any way.
104		97
105	This recipe is simply a comma-separated list of C<address:port> pairs (for	98	=item binds - C<ip:port>
106	TCP/IP, other protocols might look different).
107		99
108	Node references come in two flavours: resolved (containing only numerical	100	Nodes can only talk to each other by creating some kind of connection to
109	addresses) or unresolved (where hostnames are used instead of addresses).	101	each other. To do this, nodes should listen on one or more local transport
		102	endpoints - binds. Currently, only standard C<ip:port> specifications can
		103	be used, which specify TCP ports to listen on.
110		104
111	Before using an unresolved node reference in a message you first have to	105	=item seeds - C<host:port>
112	resolve it.	106
		107	When a node starts, it knows nothing about the network. To teach the node
		108	about the network it first has to contact some other node within the
		109	network. This node is called a seed.
		110
		111	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		112	are expected to be long-running, and at least one of those should always
		113	be available. When nodes run out of connections (e.g. due to a network
		114	error), they try to re-establish connections to some seednodes again to
		115	join the network.
		116
		117	Apart from being sued for seeding, seednodes are not special in any way -
		118	every public node can be a seednode.
113		119
114	=back	120	=back
115		121
116	=head1 VARIABLES/FUNCTIONS	122	=head1 VARIABLES/FUNCTIONS
117		123
…		…
132	use base "Exporter";	138	use base "Exporter";
133		139
134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
135		141
136	our @EXPORT = qw(	142	our @EXPORT = qw(
137	NODE $NODE *SELF node_of _any_	143	NODE $NODE *SELF node_of after
138	resolve_node initialise_node	144	initialise_node
139	snd rcv mon kil reg psub spawn	145	snd rcv mon mon_guard kil reg psub spawn
140	port	146	port
141	);	147	);
142		148
143	our $SELF;	149	our $SELF;
144		150
…		…
148	kil $SELF, die => $msg;	154	kil $SELF, die => $msg;
149	}	155	}
150		156
151	=item $thisnode = NODE / $NODE	157	=item $thisnode = NODE / $NODE
152		158
153	The C<NODE> function returns, and the C<$NODE> variable contains	159	The C<NODE> function returns, and the C<$NODE> variable contains, the node
154	the noderef of the local node. The value is initialised by a call	160	ID of the node running in the current process. This value is initialised by
155	to C<become_public> or C<become_slave>, after which all local port	161	a call to C<initialise_node>.
156	identifiers become invalid.
157		162
158	=item $noderef = node_of $port	163	=item $nodeid = node_of $port
159		164
160	Extracts and returns the noderef from a portid or a noderef.	165	Extracts and returns the node ID from a port ID or a node ID.
161		166
162	=item initialise_node $noderef, $seednode, $seednode...	167	=item initialise_node $profile_name, key => value...
163		168
164	=item initialise_node "slave/", $master, $master...
165
166	Before a node can talk to other nodes on the network it has to initialise	169	Before a node can talk to other nodes on the network (i.e. enter
167	itself - the minimum a node needs to know is it's own name, and optionally	170	"distributed mode") it has to initialise itself - the minimum a node needs
168	it should know the noderefs of some other nodes in the network.	171	to know is its own name, and optionally it should know the addresses of
		172	some other nodes in the network to discover other nodes.
169		173
170	This function initialises a node - it must be called exactly once (or	174	This function initialises a node - it must be called exactly once (or
171	never) before calling other AnyEvent::MP functions.	175	never) before calling other AnyEvent::MP functions.
172		176
173	All arguments (optionally except for the first) are noderefs, which can be	177	The first argument is a profile name. If it is C<undef> or missing, then
174	either resolved or unresolved.	178	the current nodename will be used instead (i.e. F<uname -n>).
175		179
176	The first argument will be looked up in the configuration database first	180	The function first looks up the profile in the aemp configuration (see the
177	(if it is C<undef> then the current nodename will be used instead) to find	181	L<aemp> commandline utility). the profile is calculated as follows:
178	the relevant configuration profile (see L<aemp>). If none is found then
179	the default configuration is used. The configuration supplies additional
180	seed/master nodes and can override the actual noderef.
181		182
182	There are two types of networked nodes, public nodes and slave nodes:	183	First, all remaining key => value pairs will be used. Then they will be
		184	overwritten by any values specified in the global default configuration
		185	(see the F<aemp> utility), then the chain of profiles selected, if
		186	any. That means that the values specified in the profile have highest
		187	priority and the values specified via C<initialise_node> have lowest
		188	priority.
183		189
184	=over 4	190	If the profile specifies a node ID, then this will become the node ID of
		191	this process. If not, then the profile name will be used as node ID. The
		192	special node ID of C<anon/> will be replaced by a random node ID.
185		193
186	=item public nodes	194	The next step is to look up the binds in the profile, followed by binding
		195	aemp protocol listeners on all binds specified (it is possible and valid
		196	to have no binds, meaning that the node cannot be contacted form the
		197	outside. This means the node cannot talk to other nodes that also have no
		198	binds, but it can still talk to all "normal" nodes).
187		199
188	For public nodes, C<$noderef> (supplied either directly to	200	If the profile does not specify a binds list, then the node ID will be
189	C<initialise_node> or indirectly via a profile or the nodename) must be a	201	treated as if it were of the form C<host:port>, which will be resolved and
190	noderef (possibly unresolved, in which case it will be resolved).	202	used as binds list.
191		203
192	After resolving, the node will bind itself on all endpoints and try to	204	Lastly, the seeds list from the profile is passed to the
193	connect to all additional C<$seednodes> that are specified. Seednodes are	205	L<AnyEvent::MP::Global> module, which will then use it to keep
194	optional and can be used to quickly bootstrap the node into an existing	206	connectivity with at least on of those seed nodes at any point in time.
195	network.
196		207
197	=item slave nodes
198
199	When the C<$noderef> (either as given or overriden by the config file)
200	is the special string C<slave/>, then the node will become a slave
201	node. Slave nodes cannot be contacted from outside and will route most of
202	their traffic to the master node that they attach to.
203
204	At least one additional noderef is required (either by specifying it
205	directly or because it is part of the configuration profile): The node
206	will try to connect to all of them and will become a slave attached to the
207	first node it can successfully connect to.
208
209	=back
210
211	This function will block until all nodes have been resolved and, for slave
212	nodes, until it has successfully established a connection to a master
213	server.
214
215	Example: become a public node listening on the guessed noderef, or the one	208	Example: become a distributed node listening on the guessed noderef, or
216	specified via C<aemp> for the current node. This should be the most common	209	the one specified via C<aemp> for the current node. This should be the
217	form of invocation for "daemon"-type nodes.	210	most common form of invocation for "daemon"-type nodes.
218		211
219	initialise_node;	212	initialise_node;
220		213
221	Example: become a slave node to any of the the seednodes specified via	214	Example: become an anonymous node. This form is often used for commandline
222	C<aemp>. This form is often used for commandline clients.	215	clients.
223		216
224	initialise_node "slave/";	217	initialise_node "anon/";
225		218
226	Example: become a slave node to any of the specified master servers. This	219	Example: become a distributed node. If there is no profile of the given
227	form is also often used for commandline clients.	220	name, or no binds list was specified, resolve C<localhost:4044> and bind
228		221	on the resulting addresses.
229	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
230
231	Example: become a public node, and try to contact some well-known master
232	servers to become part of the network.
233
234	initialise_node undef, "master1", "master2";
235
236	Example: become a public node listening on port C<4041>.
237
238	initialise_node 4041;
239
240	Example: become a public node, only visible on localhost port 4044.
241		222
242	initialise_node "localhost:4044";	223	initialise_node "localhost:4044";
243
244	=item $cv = resolve_node $noderef
245
246	Takes an unresolved node reference that may contain hostnames and
247	abbreviated IDs, resolves all of them and returns a resolved node
248	reference.
249
250	In addition to C<address:port> pairs allowed in resolved noderefs, the
251	following forms are supported:
252
253	=over 4
254
255	=item the empty string
256
257	An empty-string component gets resolved as if the default port (4040) was
258	specified.
259
260	=item naked port numbers (e.g. C<1234>)
261
262	These are resolved by prepending the local nodename and a colon, to be
263	further resolved.
264
265	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
266
267	These are resolved by using AnyEvent::DNS to resolve them, optionally
268	looking up SRV records for the C<aemp=4040> port, if no port was
269	specified.
270
271	=back
272		224
273	=item $SELF	225	=item $SELF
274		226
275	Contains the current port id while executing C<rcv> callbacks or C<psub>	227	Contains the current port id while executing C<rcv> callbacks or C<psub>
276	blocks.	228	blocks.
277		229
278	=item SELF, %SELF, @SELF...	230	=item *SELF, SELF, %SELF, @SELF...
279		231
280	Due to some quirks in how perl exports variables, it is impossible to	232	Due to some quirks in how perl exports variables, it is impossible to
281	just export C<$SELF>, all the symbols called C<SELF> are exported by this	233	just export C<$SELF>, all the symbols named C<SELF> are exported by this
282	module, but only C<$SELF> is currently used.	234	module, but only C<$SELF> is currently used.
283		235
284	=item snd $port, type => @data	236	=item snd $port, type => @data
285		237
286	=item snd $port, @msg	238	=item snd $port, @msg
287		239
288	Send the given message to the given port ID, which can identify either	240	Send the given message to the given port, which can identify either a
289	a local or a remote port, and can be either a string or soemthignt hat	241	local or a remote port, and must be a port ID.
290	stringifies a sa port ID (such as a port object :).
291		242
292	While the message can be about anything, it is highly recommended to use a	243	While the message can be almost anything, it is highly recommended to
293	string as first element (a portid, or some word that indicates a request	244	use a string as first element (a port ID, or some word that indicates a
294	type etc.).	245	request type etc.) and to consist if only simple perl values (scalars,
		246	arrays, hashes) - if you think you need to pass an object, think again.
295		247
296	The message data effectively becomes read-only after a call to this	248	The message data logically becomes read-only after a call to this
297	function: modifying any argument is not allowed and can cause many	249	function: modifying any argument (or values referenced by them) is
298	problems.	250	forbidden, as there can be considerable time between the call to C<snd>
		251	and the time the message is actually being serialised - in fact, it might
		252	never be copied as within the same process it is simply handed to the
		253	receiving port.
299		254
300	The type of data you can transfer depends on the transport protocol: when	255	The type of data you can transfer depends on the transport protocol: when
301	JSON is used, then only strings, numbers and arrays and hashes consisting	256	JSON is used, then only strings, numbers and arrays and hashes consisting
302	of those are allowed (no objects). When Storable is used, then anything	257	of those are allowed (no objects). When Storable is used, then anything
303	that Storable can serialise and deserialise is allowed, and for the local	258	that Storable can serialise and deserialise is allowed, and for the local
304	node, anything can be passed.	259	node, anything can be passed. Best rely only on the common denominator of
		260	these.
305		261
306	=item $local_port = port	262	=item $local_port = port
307		263
308	Create a new local port object that can be used either as a pattern	264	Create a new local port object and returns its port ID. Initially it has
309	matching port ("full port") or a single-callback port ("miniport"),	265	no callbacks set and will throw an error when it receives messages.
310	depending on how C<rcv> callbacks are bound to the object.
311		266
312	=item $port = port { my @msg = @_; $finished }	267	=item $local_port = port { my @msg = @_ }
313		268
314	Creates a "miniport", that is, a very lightweight port without any pattern	269	Creates a new local port, and returns its ID. Semantically the same as
315	matching behind it, and returns its ID. Semantically the same as creating
316	a port and calling C<rcv $port, $callback> on it.	270	creating a port and calling C<rcv $port, $callback> on it.
317		271
318	The block will be called for every message received on the port. When the	272	The block will be called for every message received on the port, with the
319	callback returns a true value its job is considered "done" and the port	273	global variable C<$SELF> set to the port ID. Runtime errors will cause the
320	will be destroyed. Otherwise it will stay alive.	274	port to be C<kil>ed. The message will be passed as-is, no extra argument
		275	(i.e. no port ID) will be passed to the callback.
321		276
322	The message will be passed as-is, no extra argument (i.e. no port id) will	277	If you want to stop/destroy the port, simply C<kil> it:
323	be passed to the callback.
324		278
325	If you need the local port id in the callback, this works nicely:	279	my $port = port {
326		280	my @msg = @_;
327	my $port; $port = port {	281	...
328	snd $otherport, reply => $port;	282	kil $SELF;
329	};	283	};
330		284
331	=cut	285	=cut
332		286
333	sub rcv($@);	287	sub rcv($@);
		288
		289	sub _kilme {
		290	die "received message on port without callback";
		291	}
334		292
335	sub port(;&) {	293	sub port(;&) {
336	my $id = "$UNIQ." . $ID++;	294	my $id = "$UNIQ." . $ID++;
337	my $port = "$NODE#$id";	295	my $port = "$NODE#$id";
338		296
339	if (@_) {	297	rcv $port, shift \|\| \&_kilme;
340	rcv $port, shift;
341	} else {
342	$PORT{$id} = sub { }; # nop
343	}
344		298
345	$port	299	$port
346	}	300	}
347		301
348	=item reg $port, $name
349
350	=item reg $name
351
352	Registers the given port (or C<$SELF><<< if missing) under the name
353	C<$name>. If the name already exists it is replaced.
354
355	A port can only be registered under one well known name.
356
357	A port automatically becomes unregistered when it is killed.
358
359	=cut
360
361	sub reg(@) {
362	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
363
364	$REG{$_[0]} = $port;
365	}
366
367	=item rcv $port, $callback->(@msg)	302	=item rcv $local_port, $callback->(@msg)
368		303
369	Replaces the callback on the specified miniport (after converting it to	304	Replaces the default callback on the specified port. There is no way to
370	one if required).	305	remove the default callback: use C<sub { }> to disable it, or better
371		306	C<kil> the port when it is no longer needed.
372	=item rcv $port, tagstring => $callback->(@msg), ...
373
374	=item rcv $port, $smartmatch => $callback->(@msg), ...
375
376	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
377
378	Register callbacks to be called on matching messages on the given full
379	port (after converting it to one if required) and return the port.
380
381	The callback has to return a true value when its work is done, after
382	which is will be removed, or a false value in which case it will stay
383	registered.
384		307
385	The global C<$SELF> (exported by this module) contains C<$port> while	308	The global C<$SELF> (exported by this module) contains C<$port> while
386	executing the callback.	309	executing the callback. Runtime errors during callback execution will
		310	result in the port being C<kil>ed.
387		311
388	Runtime errors during callback execution will result in the port being	312	The default callback received all messages not matched by a more specific
389	C<kil>ed.	313	C<tag> match.
390		314
391	If the match is an array reference, then it will be matched against the	315	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
392	first elements of the message, otherwise only the first element is being
393	matched.
394		316
395	Any element in the match that is specified as C<_any_> (a function	317	Register (or replace) callbacks to be called on messages starting with the
396	exported by this module) matches any single element of the message.	318	given tag on the given port (and return the port), or unregister it (when
		319	C<$callback> is C<$undef> or missing). There can only be one callback
		320	registered for each tag.
397		321
398	While not required, it is highly recommended that the first matching	322	The original message will be passed to the callback, after the first
399	element is a string identifying the message. The one-string-only match is	323	element (the tag) has been removed. The callback will use the same
400	also the most efficient match (by far).	324	environment as the default callback (see above).
401		325
402	Example: create a port and bind receivers on it in one go.	326	Example: create a port and bind receivers on it in one go.
403		327
404	my $port = rcv port,	328	my $port = rcv port,
405	msg1 => sub { ...; 0 },	329	msg1 => sub { ... },
406	msg2 => sub { ...; 0 },	330	msg2 => sub { ... },
407	;	331	;
408		332
409	Example: create a port, bind receivers and send it in a message elsewhere	333	Example: create a port, bind receivers and send it in a message elsewhere
410	in one go:	334	in one go:
411		335
412	snd $otherport, reply =>	336	snd $otherport, reply =>
413	rcv port,	337	rcv port,
414	msg1 => sub { ...; 0 },	338	msg1 => sub { ... },
415	...	339	...
416	;	340	;
		341
		342	Example: temporarily register a rcv callback for a tag matching some port
		343	(e.g. for a rpc reply) and unregister it after a message was received.
		344
		345	rcv $port, $otherport => sub {
		346	my @reply = @_;
		347
		348	rcv $SELF, $otherport;
		349	};
417		350
418	=cut	351	=cut
419		352
420	sub rcv($@) {	353	sub rcv($@) {
421	my $port = shift;	354	my $port = shift;
422	my ($noderef, $portid) = split /#/, $port, 2;	355	my ($noderef, $portid) = split /#/, $port, 2;
423		356
424	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	357	$NODE{$noderef} == $NODE{""}
425	or Carp::croak "$port: rcv can only be called on local ports, caught";	358	or Carp::croak "$port: rcv can only be called on local ports, caught";
426		359
427	if (@_ == 1) {	360	while (@_) {
		361	if (ref $_[0]) {
		362	if (my $self = $PORT_DATA{$portid}) {
		363	"AnyEvent::MP::Port" eq ref $self
		364	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		365
		366	$self->[2] = shift;
		367	} else {
428	my $cb = shift;	368	my $cb = shift;
429	delete $PORT_DATA{$portid};
430	$PORT{$portid} = sub {	369	$PORT{$portid} = sub {
431	local $SELF = $port;	370	local $SELF = $port;
432	eval {	371	eval { &$cb }; _self_die if $@;
433	&$cb	372	};
434	and kil $port;
435	};	373	}
436	_self_die if $@;	374	} elsif (defined $_[0]) {
437	};
438	} else {
439	my $self = $PORT_DATA{$portid} \|\|= do {	375	my $self = $PORT_DATA{$portid} \|\|= do {
440	my $self = bless {	376	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
441	id => $port,
442	}, "AnyEvent::MP::Port";
443		377
444	$PORT{$portid} = sub {	378	$PORT{$portid} = sub {
445	local $SELF = $port;	379	local $SELF = $port;
446		380
447	eval {
448	for (@{ $self->{rc0}{$_[0]} }) {	381	if (my $cb = $self->[1]{$_[0]}) {
449	$_ && &{$_->[0]}	382	shift;
450	&& undef $_;	383	eval { &$cb }; _self_die if $@;
451	}	384	} else {
452
453	for (@{ $self->{rcv}{$_[0]} }) {
454	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
455	&& &{$_->[0]}	385	&{ $self->[0] };
456	&& undef $_;
457	}
458
459	for (@{ $self->{any} }) {
460	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
461	&& &{$_->[0]}
462	&& undef $_;
463	}	386	}
464	};	387	};
465	_self_die if $@;	388
		389	$self
466	};	390	};
467		391
468	$self
469	};
470
471	"AnyEvent::MP::Port" eq ref $self	392	"AnyEvent::MP::Port" eq ref $self
472	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	393	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
473		394
474	while (@_) {
475	my ($match, $cb) = splice @_, 0, 2;	395	my ($tag, $cb) = splice @_, 0, 2;
476		396
477	if (!ref $match) {	397	if (defined $cb) {
478	push @{ $self->{rc0}{$match} }, [$cb];	398	$self->[1]{$tag} = $cb;
479	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
480	my ($type, @match) = @$match;
481	@match
482	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
483	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
484	} else {	399	} else {
485	push @{ $self->{any} }, [$cb, $match];	400	delete $self->[1]{$tag};
486	}	401	}
487	}	402	}
488	}	403	}
489		404
490	$port	405	$port
…		…
526	$res	441	$res
527	}	442	}
528	}	443	}
529	}	444	}
530		445
531	=item $guard = mon $port, $cb->(@reason)	446	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
532		447
533	=item $guard = mon $port, $rcvport	448	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
534		449
535	=item $guard = mon $port	450	=item $guard = mon $port # kill $SELF when $port dies
536		451
537	=item $guard = mon $port, $rcvport, @msg	452	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
538		453
539	Monitor the given port and do something when the port is killed or	454	Monitor the given port and do something when the port is killed or
540	messages to it were lost, and optionally return a guard that can be used	455	messages to it were lost, and optionally return a guard that can be used
541	to stop monitoring again.	456	to stop monitoring again.
542		457
543	C<mon> effectively guarantees that, in the absence of hardware failures,	458	C<mon> effectively guarantees that, in the absence of hardware failures,
544	that after starting the monitor, either all messages sent to the port	459	after starting the monitor, either all messages sent to the port will
545	will arrive, or the monitoring action will be invoked after possible	460	arrive, or the monitoring action will be invoked after possible message
546	message loss has been detected. No messages will be lost "in between"	461	loss has been detected. No messages will be lost "in between" (after
547	(after the first lost message no further messages will be received by the	462	the first lost message no further messages will be received by the
548	port). After the monitoring action was invoked, further messages might get	463	port). After the monitoring action was invoked, further messages might get
549	delivered again.	464	delivered again.
		465
		466	Note that monitoring-actions are one-shot: once messages are lost (and a
		467	monitoring alert was raised), they are removed and will not trigger again.
550		468
551	In the first form (callback), the callback is simply called with any	469	In the first form (callback), the callback is simply called with any
552	number of C<@reason> elements (no @reason means that the port was deleted	470	number of C<@reason> elements (no @reason means that the port was deleted
553	"normally"). Note also that I<< the callback B<must> never die >>, so use	471	"normally"). Note also that I<< the callback B<must> never die >>, so use
554	C<eval> if unsure.	472	C<eval> if unsure.
…		…
616	is killed, the references will be freed.	534	is killed, the references will be freed.
617		535
618	Optionally returns a guard that will stop the monitoring.	536	Optionally returns a guard that will stop the monitoring.
619		537
620	This function is useful when you create e.g. timers or other watchers and	538	This function is useful when you create e.g. timers or other watchers and
621	want to free them when the port gets killed:	539	want to free them when the port gets killed (note the use of C<psub>):
622		540
623	$port->rcv (start => sub {	541	$port->rcv (start => sub {
624	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	542	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
625	undef $timer if 0.9 < rand;	543	undef $timer if 0.9 < rand;
626	});	544	});
627	});	545	});
628		546
629	=cut	547	=cut
…		…
638		556
639	=item kil $port[, @reason]	557	=item kil $port[, @reason]
640		558
641	Kill the specified port with the given C<@reason>.	559	Kill the specified port with the given C<@reason>.
642		560
643	If no C<@reason> is specified, then the port is killed "normally" (linked	561	If no C<@reason> is specified, then the port is killed "normally" (ports
644	ports will not be kileld, or even notified).	562	monitoring other ports will not necessarily die because a port dies
		563	"normally").
645		564
646	Otherwise, linked ports get killed with the same reason (second form of	565	Otherwise, linked ports get killed with the same reason (second form of
647	C<mon>, see below).	566	C<mon>, see above).
648		567
649	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	568	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
650	will be reported as reason C<< die => $@ >>.	569	will be reported as reason C<< die => $@ >>.
651		570
652	Transport/communication errors are reported as C<< transport_error =>	571	Transport/communication errors are reported as C<< transport_error =>
…		…
657	=item $port = spawn $node, $initfunc[, @initdata]	576	=item $port = spawn $node, $initfunc[, @initdata]
658		577
659	Creates a port on the node C<$node> (which can also be a port ID, in which	578	Creates a port on the node C<$node> (which can also be a port ID, in which
660	case it's the node where that port resides).	579	case it's the node where that port resides).
661		580
662	The port ID of the newly created port is return immediately, and it is	581	The port ID of the newly created port is returned immediately, and it is
663	permissible to immediately start sending messages or monitor the port.	582	possible to immediately start sending messages or to monitor the port.
664		583
665	After the port has been created, the init function is	584	After the port has been created, the init function is called on the remote
666	called. This function must be a fully-qualified function name	585	node, in the same context as a C<rcv> callback. This function must be a
667	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	586	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
668	program, use C<::name>.	587	specify a function in the main program, use C<::name>.
669		588
670	If the function doesn't exist, then the node tries to C<require>	589	If the function doesn't exist, then the node tries to C<require>
671	the package, then the package above the package and so on (e.g.	590	the package, then the package above the package and so on (e.g.
672	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	591	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
673	exists or it runs out of package names.	592	exists or it runs out of package names.
674		593
675	The init function is then called with the newly-created port as context	594	The init function is then called with the newly-created port as context
676	object (C<$SELF>) and the C<@initdata> values as arguments.	595	object (C<$SELF>) and the C<@initdata> values as arguments.
677		596
678	A common idiom is to pass your own port, monitor the spawned port, and	597	A common idiom is to pass a local port, immediately monitor the spawned
679	in the init function, monitor the original port. This two-way monitoring	598	port, and in the remote init function, immediately monitor the passed
680	ensures that both ports get cleaned up when there is a problem.	599	local port. This two-way monitoring ensures that both ports get cleaned up
		600	when there is a problem.
681		601
682	Example: spawn a chat server port on C<$othernode>.	602	Example: spawn a chat server port on C<$othernode>.
683		603
684	# this node, executed from within a port context:	604	# this node, executed from within a port context:
685	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	605	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
715	my $id = "$RUNIQ." . $ID++;	635	my $id = "$RUNIQ." . $ID++;
716		636
717	$_[0] =~ /::/	637	$_[0] =~ /::/
718	or Carp::croak "spawn init function must be a fully-qualified name, caught";	638	or Carp::croak "spawn init function must be a fully-qualified name, caught";
719		639
720	($NODE{$noderef} \|\| add_node $noderef)	640	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
721	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
722		641
723	"$noderef#$id"	642	"$noderef#$id"
724	}	643	}
725		644
726	=back	645	=item after $timeout, @msg
727		646
728	=head1 NODE MESSAGES	647	=item after $timeout, $callback
729		648
730	Nodes understand the following messages sent to them. Many of them take	649	Either sends the given message, or call the given callback, after the
731	arguments called C<@reply>, which will simply be used to compose a reply	650	specified number of seconds.
732	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
733	the remaining arguments are simply the message data.
734		651
735	While other messages exist, they are not public and subject to change.	652	This is simply a utility function that comes in handy at times - the
		653	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		654	so it may go away in the future.
736		655
737	=over 4
738
739	=cut	656	=cut
740		657
741	=item lookup => $name, @reply	658	sub after($@) {
		659	my ($timeout, @action) = @_;
742		660
743	Replies with the port ID of the specified well-known port, or C<undef>.	661	my $t; $t = AE::timer $timeout, 0, sub {
744		662	undef $t;
745	=item devnull => ...	663	ref $action[0]
746		664	? $action[0]()
747	Generic data sink/CPU heat conversion.	665	: snd @action;
748		666	};
749	=item relay => $port, @msg	667	}
750
751	Simply forwards the message to the given port.
752
753	=item eval => $string[ @reply]
754
755	Evaluates the given string. If C<@reply> is given, then a message of the
756	form C<@reply, $@, @evalres> is sent.
757
758	Example: crash another node.
759
760	snd $othernode, eval => "exit";
761
762	=item time => @reply
763
764	Replies the the current node time to C<@reply>.
765
766	Example: tell the current node to send the current time to C<$myport> in a
767	C<timereply> message.
768
769	snd $NODE, time => $myport, timereply => 1, 2;
770	# => snd $myport, timereply => 1, 2, <time>
771		668
772	=back	669	=back
773		670
774	=head1 AnyEvent::MP vs. Distributed Erlang	671	=head1 AnyEvent::MP vs. Distributed Erlang
775		672
…		…
785		682
786	Despite the similarities, there are also some important differences:	683	Despite the similarities, there are also some important differences:
787		684
788	=over 4	685	=over 4
789		686
790	=item * Node references contain the recipe on how to contact them.	687	=item * Node IDs are arbitrary strings in AEMP.
791		688
792	Erlang relies on special naming and DNS to work everywhere in the	689	Erlang relies on special naming and DNS to work everywhere in the same
793	same way. AEMP relies on each node knowing it's own address(es), with	690	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
794	convenience functionality.	691	configuraiton or DNS), but will otherwise discover other odes itself.
795		692
796	This means that AEMP requires a less tightly controlled environment at the	693	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
797	cost of longer node references and a slightly higher management overhead.	694	uses "local ports are like remote ports".
		695
		696	The failure modes for local ports are quite different (runtime errors
		697	only) then for remote ports - when a local port dies, you I<know> it dies,
		698	when a connection to another node dies, you know nothing about the other
		699	port.
		700
		701	Erlang pretends remote ports are as reliable as local ports, even when
		702	they are not.
		703
		704	AEMP encourages a "treat remote ports differently" philosophy, with local
		705	ports being the special case/exception, where transport errors cannot
		706	occur.
798		707
799	=item * Erlang uses processes and a mailbox, AEMP does not queue.	708	=item * Erlang uses processes and a mailbox, AEMP does not queue.
800		709
801	Erlang uses processes that selctively receive messages, and therefore	710	Erlang uses processes that selectively receive messages, and therefore
802	needs a queue. AEMP is event based, queuing messages would serve no useful	711	needs a queue. AEMP is event based, queuing messages would serve no
803	purpose.	712	useful purpose. For the same reason the pattern-matching abilities of
		713	AnyEvent::MP are more limited, as there is little need to be able to
		714	filter messages without dequeing them.
804		715
805	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	716	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
806		717
807	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	718	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
808		719
809	Sending messages in Erlang is synchronous and blocks the process. AEMP	720	Sending messages in Erlang is synchronous and blocks the process (and
810	sends are immediate, connection establishment is handled in the	721	so does not need a queue that can overflow). AEMP sends are immediate,
811	background.	722	connection establishment is handled in the background.
812		723
813	=item * Erlang can silently lose messages, AEMP cannot.	724	=item * Erlang suffers from silent message loss, AEMP does not.
814		725
815	Erlang makes few guarantees on messages delivery - messages can get lost	726	Erlang makes few guarantees on messages delivery - messages can get lost
816	without any of the processes realising it (i.e. you send messages a, b,	727	without any of the processes realising it (i.e. you send messages a, b,
817	and c, and the other side only receives messages a and c).	728	and c, and the other side only receives messages a and c).
818		729
819	AEMP guarantees correct ordering, and the guarantee that there are no	730	AEMP guarantees correct ordering, and the guarantee that after one message
820	holes in the message sequence.	731	is lost, all following ones sent to the same port are lost as well, until
821		732	monitoring raises an error, so there are no silent "holes" in the message
822	=item * In Erlang, processes can be declared dead and later be found to be	733	sequence.
823	alive.
824
825	In Erlang it can happen that a monitored process is declared dead and
826	linked processes get killed, but later it turns out that the process is
827	still alive - and can receive messages.
828
829	In AEMP, when port monitoring detects a port as dead, then that port will
830	eventually be killed - it cannot happen that a node detects a port as dead
831	and then later sends messages to it, finding it is still alive.
832		734
833	=item * Erlang can send messages to the wrong port, AEMP does not.	735	=item * Erlang can send messages to the wrong port, AEMP does not.
834		736
835	In Erlang it is quite possible that a node that restarts reuses a process	737	In Erlang it is quite likely that a node that restarts reuses a process ID
836	ID known to other nodes for a completely different process, causing	738	known to other nodes for a completely different process, causing messages
837	messages destined for that process to end up in an unrelated process.	739	destined for that process to end up in an unrelated process.
838		740
839	AEMP never reuses port IDs, so old messages or old port IDs floating	741	AEMP never reuses port IDs, so old messages or old port IDs floating
840	around in the network will not be sent to an unrelated port.	742	around in the network will not be sent to an unrelated port.
841		743
842	=item * Erlang uses unprotected connections, AEMP uses secure	744	=item * Erlang uses unprotected connections, AEMP uses secure
843	authentication and can use TLS.	745	authentication and can use TLS.
844		746
845	AEMP can use a proven protocol - SSL/TLS - to protect connections and	747	AEMP can use a proven protocol - TLS - to protect connections and
846	securely authenticate nodes.	748	securely authenticate nodes.
847		749
848	=item * The AEMP protocol is optimised for both text-based and binary	750	=item * The AEMP protocol is optimised for both text-based and binary
849	communications.	751	communications.
850		752
851	The AEMP protocol, unlike the Erlang protocol, supports both	753	The AEMP protocol, unlike the Erlang protocol, supports both programming
852	language-independent text-only protocols (good for debugging) and binary,	754	language independent text-only protocols (good for debugging) and binary,
853	language-specific serialisers (e.g. Storable).	755	language-specific serialisers (e.g. Storable). By default, unless TLS is
		756	used, the protocol is actually completely text-based.
854		757
855	It has also been carefully designed to be implementable in other languages	758	It has also been carefully designed to be implementable in other languages
856	with a minimum of work while gracefully degrading fucntionality to make the	759	with a minimum of work while gracefully degrading functionality to make the
857	protocol simple.	760	protocol simple.
858		761
859	=item * AEMP has more flexible monitoring options than Erlang.	762	=item * AEMP has more flexible monitoring options than Erlang.
860		763
861	In Erlang, you can chose to receive I<all> exit signals as messages	764	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
864	Erlang, as one can choose between automatic kill, exit message or callback	767	Erlang, as one can choose between automatic kill, exit message or callback
865	on a per-process basis.	768	on a per-process basis.
866		769
867	=item * Erlang tries to hide remote/local connections, AEMP does not.	770	=item * Erlang tries to hide remote/local connections, AEMP does not.
868		771
869	Monitoring in Erlang is not an indicator of process death/crashes,	772	Monitoring in Erlang is not an indicator of process death/crashes, in the
870	as linking is (except linking is unreliable in Erlang).	773	same way as linking is (except linking is unreliable in Erlang).
871		774
872	In AEMP, you don't "look up" registered port names or send to named ports	775	In AEMP, you don't "look up" registered port names or send to named ports
873	that might or might not be persistent. Instead, you normally spawn a port	776	that might or might not be persistent. Instead, you normally spawn a port
874	on the remote node. The init function monitors the you, and you monitor	777	on the remote node. The init function monitors you, and you monitor the
875	the remote port. Since both monitors are local to the node, they are much	778	remote port. Since both monitors are local to the node, they are much more
876	more reliable.	779	reliable (no need for C<spawn_link>).
877		780
878	This also saves round-trips and avoids sending messages to the wrong port	781	This also saves round-trips and avoids sending messages to the wrong port
879	(hard to do in Erlang).	782	(hard to do in Erlang).
880		783
881	=back	784	=back
882		785
883	=head1 RATIONALE	786	=head1 RATIONALE
884		787
885	=over 4	788	=over 4
886		789
887	=item Why strings for ports and noderefs, why not objects?	790	=item Why strings for port and node IDs, why not objects?
888		791
889	We considered "objects", but found that the actual number of methods	792	We considered "objects", but found that the actual number of methods
890	thatc an be called are very low. Since port IDs and noderefs travel over	793	that can be called are quite low. Since port and node IDs travel over
891	the network frequently, the serialising/deserialising would add lots of	794	the network frequently, the serialising/deserialising would add lots of
892	overhead, as well as having to keep a proxy object.	795	overhead, as well as having to keep a proxy object everywhere.
893		796
894	Strings can easily be printed, easily serialised etc. and need no special	797	Strings can easily be printed, easily serialised etc. and need no special
895	procedures to be "valid".	798	procedures to be "valid".
896		799
897	And a a miniport consists of a single closure stored in a global hash - it	800	And as a result, a miniport consists of a single closure stored in a
898	can't become much cheaper.	801	global hash - it can't become much cheaper.
899		802
900	=item Why favour JSON, why not real serialising format such as Storable?	803	=item Why favour JSON, why not a real serialising format such as Storable?
901		804
902	In fact, any AnyEvent::MP node will happily accept Storable as framing	805	In fact, any AnyEvent::MP node will happily accept Storable as framing
903	format, but currently there is no way to make a node use Storable by	806	format, but currently there is no way to make a node use Storable by
904	default.	807	default (although all nodes will accept it).
905		808
906	The default framing protocol is JSON because a) JSON::XS is many times	809	The default framing protocol is JSON because a) JSON::XS is many times
907	faster for small messages and b) most importantly, after years of	810	faster for small messages and b) most importantly, after years of
908	experience we found that object serialisation is causing more problems	811	experience we found that object serialisation is causing more problems
909	than it gains: Just like function calls, objects simply do not travel	812	than it solves: Just like function calls, objects simply do not travel
910	easily over the network, mostly because they will always be a copy, so you	813	easily over the network, mostly because they will always be a copy, so you
911	always have to re-think your design.	814	always have to re-think your design.
912		815
913	Keeping your messages simple, concentrating on data structures rather than	816	Keeping your messages simple, concentrating on data structures rather than
914	objects, will keep your messages clean, tidy and efficient.	817	objects, will keep your messages clean, tidy and efficient.
915		818
916	=back	819	=back
917		820
918	=head1 SEE ALSO	821	=head1 SEE ALSO
919		822
		823	L<AnyEvent::MP::Intro> - a gentle introduction.
		824
		825	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		826
		827	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		828	your applications.
		829
920	L<AnyEvent>.	830	L<AnyEvent>.
921		831
922	=head1 AUTHOR	832	=head1 AUTHOR
923		833
924	Marc Lehmann <schmorp@schmorp.de>	834	Marc Lehmann <schmorp@schmorp.de>

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs. Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.69 by root, Sun Aug 30 18:51:49 2009 UTC