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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs.
Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC

…		…
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
13	$SELF # receiving/own port id in rcv callbacks	13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node;
14		17
15	# ports are message endpoints	18	# ports are message endpoints
16		19
17	# sending messages	20	# sending messages
18	snd $port, type => data...;	21	snd $port, type => data...;
19	snd $port, @msg;	22	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
21		24
22	# miniports	25	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
24		27
25	# full ports	28	# creating/using ports, tagged message matching
26	my $port = port;	29	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		32
31	# remote ports	33	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	34	my $port = spawn $node, $initfunc, @initdata;
33
34	# more, smarter, matches (_any_ is exported by this module)
35	rcv $port, [child_died => $pid] => sub { ...
36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
37		35
38	# monitoring	36	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	37	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	38	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	39	mon $port, $otherport, @msg # send message on death
42		40
43	=head1 CURRENT STATUS	41	=head1 CURRENT STATUS
44		42
45	AnyEvent::MP - stable API, should work	43	AnyEvent::MP - stable API, should work
46	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - outdated
47	AnyEvent::MP::Kernel - WIP
48	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
49		49
50	stay tuned.	50	stay tuned.
51		51
52	=head1 DESCRIPTION	52	=head1 DESCRIPTION
53		53
54	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
55		55
56	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
57	on the same or other hosts.	57	on the same or other hosts, and you can supervise entities remotely.
58		58
59	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>
60	manual page.	60	manual page and the examples under F<eg/>.
61		61
62	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is a bit underdocumented.
63	so do not use. This was uploaded mainly to reserve the CPAN namespace -
64	stay tuned!
65		63
66	=head1 CONCEPTS	64	=head1 CONCEPTS
67		65
68	=over 4	66	=over 4
69		67
70	=item port	68	=item port
71		69
72	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).
73		71
74	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
75	messages. All C<rcv> handlers will receive messages they match, messages	73	some messages. Messages send to ports will not be queued, regardless of
76	will not be queued.	74	anything was listening for them or not.
77		75
78	=item port id - C<noderef#portname>	76	=item port ID - C<nodeid#portname>
79		77
80	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
81	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format).
82	exception is the the node port, whose ID is identical to its node
83	reference.
84		80
85	=item node	81	=item node
86		82
87	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,
88	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
89	create new ports, among other things.	85	ports.
90		86
91	Nodes are either private (single-process only), slaves (connected to a	87	Nodes are either public (have one or more listening ports) or private
92	master node only) or public nodes (connectable from unrelated nodes).	88	(no listening ports). Private nodes cannot talk to other private nodes
		89	currently.
93		90
94	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	91	=item node ID - C<[a-za-Z0-9_\-.:]+>
95		92
96	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
97	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
98	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.
99		97
100	This recipe is simply a comma-separated list of C<address:port> pairs (for	98	=item binds - C<ip:port>
101	TCP/IP, other protocols might look different).
102		99
103	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
104	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.
105		104
106	Before using an unresolved node reference in a message you first have to	105	=item seeds - C<host:port>
107	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.
108		119
109	=back	120	=back
110		121
111	=head1 VARIABLES/FUNCTIONS	122	=head1 VARIABLES/FUNCTIONS
112		123
…		…
127	use base "Exporter";	138	use base "Exporter";
128		139
129	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
130		141
131	our @EXPORT = qw(	142	our @EXPORT = qw(
132	NODE $NODE *SELF node_of _any_	143	NODE $NODE *SELF node_of after
133	resolve_node initialise_node	144	initialise_node
134	snd rcv mon kil reg psub spawn	145	snd rcv mon mon_guard kil reg psub spawn
135	port	146	port
136	);	147	);
137		148
138	our $SELF;	149	our $SELF;
139		150
…		…
143	kil $SELF, die => $msg;	154	kil $SELF, die => $msg;
144	}	155	}
145		156
146	=item $thisnode = NODE / $NODE	157	=item $thisnode = NODE / $NODE
147		158
148	The C<NODE> function returns, and the C<$NODE> variable contains	159	The C<NODE> function returns, and the C<$NODE> variable contains, the node
149	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
150	to C<become_public> or C<become_slave>, after which all local port	161	a call to C<initialise_node>.
151	identifiers become invalid.
152		162
153	=item $noderef = node_of $port	163	=item $nodeid = node_of $port
154		164
155	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.
156		166
157	=item initialise_node $noderef, $seednode, $seednode...	167	=item initialise_node $profile_name, key => value...
158		168
159	=item initialise_node "slave/", $master, $master...
160
161	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
162	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
163	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.
164		173
165	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
166	never) before calling other AnyEvent::MP functions.	175	never) before calling other AnyEvent::MP functions.
167		176
168	All arguments are noderefs, which can be either resolved or unresolved.	177	The first argument is a profile name. If it is C<undef> or missing, then
		178	the current nodename will be used instead (i.e. F<uname -n>).
169		179
170	There are two types of networked nodes, public nodes and slave nodes:	180	The function first looks up the profile in the aemp configuration (see the
		181	L<aemp> commandline utility). the profile is calculated as follows:
171		182
172	=over 4	183	First, all remaining key => value pairs (all of which are conviniently
		184	undocumented at the moment) will be used. Then they will be overwritten by
		185	any values specified in the global default configuration (see the F<aemp>
		186	utility), then the chain of profiles selected, if any. That means that
		187	the values specified in the profile have highest priority and the values
		188	specified via C<initialise_node> have lowest priority.
173		189
174	=item public nodes	190	If the profile specifies a node ID, then this will become the node ID of
		191	this process. If not, then the profile name will be used as node ID. The
		192	special node ID of C<anon/> will be replaced by a random node ID.
175		193
176	For public nodes, C<$noderef> must either be a (possibly unresolved)	194	The next step is to look up the binds in the profile, followed by binding
177	noderef, in which case it will be resolved, or C<undef> (or missing), in	195	aemp protocol listeners on all binds specified (it is possible and valid
178	which case the noderef will be guessed.	196	to have no binds, meaning that the node cannot be contacted form the
		197	outside. This means the node cannot talk to other nodes that also have no
		198	binds, but it can still talk to all "normal" nodes).
179		199
180	Afterwards, the node will bind itself on all endpoints and try to connect	200	If the profile does not specify a binds list, then a default of C<*> is
181	to all additional C<$seednodes> that are specified. Seednodes are optional	201	used.
182	and can be used to quickly bootstrap the node into an existing network.
183		202
184	=item slave nodes	203	Lastly, the seeds list from the profile is passed to the
		204	L<AnyEvent::MP::Global> module, which will then use it to keep
		205	connectivity with at least on of those seed nodes at any point in time.
185		206
186	When the C<$noderef> is the special string C<slave/>, then the node will	207	Example: become a distributed node listening on the guessed noderef, or
187	become a slave node. Slave nodes cannot be contacted from outside and will	208	the one specified via C<aemp> for the current node. This should be the
188	route most of their traffic to the master node that they attach to.	209	most common form of invocation for "daemon"-type nodes.
189
190	At least one additional noderef is required: The node will try to connect
191	to all of them and will become a slave attached to the first node it can
192	successfully connect to.
193
194	=back
195
196	This function will block until all nodes have been resolved and, for slave
197	nodes, until it has successfully established a connection to a master
198	server.
199
200	Example: become a public node listening on the default node.
201		210
202	initialise_node;	211	initialise_node;
203		212
204	Example: become a public node, and try to contact some well-known master	213	Example: become an anonymous node. This form is often used for commandline
205	servers to become part of the network.	214	clients.
206		215
207	initialise_node undef, "master1", "master2";
208
209	Example: become a public node listening on port C<4041>.
210
211	initialise_node 4041;	216	initialise_node "anon/";
212		217
213	Example: become a public node, only visible on localhost port 4044.	218	Example: become a distributed node. If there is no profile of the given
		219	name, or no binds list was specified, resolve C<localhost:4044> and bind
		220	on the resulting addresses.
214		221
215	initialise_node "locahost:4044";	222	initialise_node "localhost:4044";
216
217	Example: become a slave node to any of the specified master servers.
218
219	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
220
221	=item $cv = resolve_node $noderef
222
223	Takes an unresolved node reference that may contain hostnames and
224	abbreviated IDs, resolves all of them and returns a resolved node
225	reference.
226
227	In addition to C<address:port> pairs allowed in resolved noderefs, the
228	following forms are supported:
229
230	=over 4
231
232	=item the empty string
233
234	An empty-string component gets resolved as if the default port (4040) was
235	specified.
236
237	=item naked port numbers (e.g. C<1234>)
238
239	These are resolved by prepending the local nodename and a colon, to be
240	further resolved.
241
242	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
243
244	These are resolved by using AnyEvent::DNS to resolve them, optionally
245	looking up SRV records for the C<aemp=4040> port, if no port was
246	specified.
247
248	=back
249		223
250	=item $SELF	224	=item $SELF
251		225
252	Contains the current port id while executing C<rcv> callbacks or C<psub>	226	Contains the current port id while executing C<rcv> callbacks or C<psub>
253	blocks.	227	blocks.
254		228
255	=item SELF, %SELF, @SELF...	229	=item *SELF, SELF, %SELF, @SELF...
256		230
257	Due to some quirks in how perl exports variables, it is impossible to	231	Due to some quirks in how perl exports variables, it is impossible to
258	just export C<$SELF>, all the symbols called C<SELF> are exported by this	232	just export C<$SELF>, all the symbols named C<SELF> are exported by this
259	module, but only C<$SELF> is currently used.	233	module, but only C<$SELF> is currently used.
260		234
261	=item snd $port, type => @data	235	=item snd $port, type => @data
262		236
263	=item snd $port, @msg	237	=item snd $port, @msg
264		238
265	Send the given message to the given port ID, which can identify either	239	Send the given message to the given port, which can identify either a
266	a local or a remote port, and can be either a string or soemthignt hat	240	local or a remote port, and must be a port ID.
267	stringifies a sa port ID (such as a port object :).
268		241
269	While the message can be about anything, it is highly recommended to use a	242	While the message can be almost anything, it is highly recommended to
270	string as first element (a portid, or some word that indicates a request	243	use a string as first element (a port ID, or some word that indicates a
271	type etc.).	244	request type etc.) and to consist if only simple perl values (scalars,
		245	arrays, hashes) - if you think you need to pass an object, think again.
272		246
273	The message data effectively becomes read-only after a call to this	247	The message data logically becomes read-only after a call to this
274	function: modifying any argument is not allowed and can cause many	248	function: modifying any argument (or values referenced by them) is
275	problems.	249	forbidden, as there can be considerable time between the call to C<snd>
		250	and the time the message is actually being serialised - in fact, it might
		251	never be copied as within the same process it is simply handed to the
		252	receiving port.
276		253
277	The type of data you can transfer depends on the transport protocol: when	254	The type of data you can transfer depends on the transport protocol: when
278	JSON is used, then only strings, numbers and arrays and hashes consisting	255	JSON is used, then only strings, numbers and arrays and hashes consisting
279	of those are allowed (no objects). When Storable is used, then anything	256	of those are allowed (no objects). When Storable is used, then anything
280	that Storable can serialise and deserialise is allowed, and for the local	257	that Storable can serialise and deserialise is allowed, and for the local
281	node, anything can be passed.	258	node, anything can be passed. Best rely only on the common denominator of
		259	these.
282		260
283	=item $local_port = port	261	=item $local_port = port
284		262
285	Create a new local port object that can be used either as a pattern	263	Create a new local port object and returns its port ID. Initially it has
286	matching port ("full port") or a single-callback port ("miniport"),	264	no callbacks set and will throw an error when it receives messages.
287	depending on how C<rcv> callbacks are bound to the object.
288		265
289	=item $port = port { my @msg = @_; $finished }	266	=item $local_port = port { my @msg = @_ }
290		267
291	Creates a "miniport", that is, a very lightweight port without any pattern	268	Creates a new local port, and returns its ID. Semantically the same as
292	matching behind it, and returns its ID. Semantically the same as creating
293	a port and calling C<rcv $port, $callback> on it.	269	creating a port and calling C<rcv $port, $callback> on it.
294		270
295	The block will be called for every message received on the port. When the	271	The block will be called for every message received on the port, with the
296	callback returns a true value its job is considered "done" and the port	272	global variable C<$SELF> set to the port ID. Runtime errors will cause the
297	will be destroyed. Otherwise it will stay alive.	273	port to be C<kil>ed. The message will be passed as-is, no extra argument
		274	(i.e. no port ID) will be passed to the callback.
298		275
299	The message will be passed as-is, no extra argument (i.e. no port id) will	276	If you want to stop/destroy the port, simply C<kil> it:
300	be passed to the callback.
301		277
302	If you need the local port id in the callback, this works nicely:	278	my $port = port {
303		279	my @msg = @_;
304	my $port; $port = port {	280	...
305	snd $otherport, reply => $port;	281	kil $SELF;
306	};	282	};
307		283
308	=cut	284	=cut
309		285
310	sub rcv($@);	286	sub rcv($@);
		287
		288	sub _kilme {
		289	die "received message on port without callback";
		290	}
311		291
312	sub port(;&) {	292	sub port(;&) {
313	my $id = "$UNIQ." . $ID++;	293	my $id = "$UNIQ." . $ID++;
314	my $port = "$NODE#$id";	294	my $port = "$NODE#$id";
315		295
316	if (@_) {	296	rcv $port, shift \|\| \&_kilme;
317	rcv $port, shift;
318	} else {
319	$PORT{$id} = sub { }; # nop
320	}
321		297
322	$port	298	$port
323	}	299	}
324		300
325	=item reg $port, $name
326
327	=item reg $name
328
329	Registers the given port (or C<$SELF><<< if missing) under the name
330	C<$name>. If the name already exists it is replaced.
331
332	A port can only be registered under one well known name.
333
334	A port automatically becomes unregistered when it is killed.
335
336	=cut
337
338	sub reg(@) {
339	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
340
341	$REG{$_[0]} = $port;
342	}
343
344	=item rcv $port, $callback->(@msg)	301	=item rcv $local_port, $callback->(@msg)
345		302
346	Replaces the callback on the specified miniport (after converting it to	303	Replaces the default callback on the specified port. There is no way to
347	one if required).	304	remove the default callback: use C<sub { }> to disable it, or better
348		305	C<kil> the port when it is no longer needed.
349	=item rcv $port, tagstring => $callback->(@msg), ...
350
351	=item rcv $port, $smartmatch => $callback->(@msg), ...
352
353	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
354
355	Register callbacks to be called on matching messages on the given full
356	port (after converting it to one if required) and return the port.
357
358	The callback has to return a true value when its work is done, after
359	which is will be removed, or a false value in which case it will stay
360	registered.
361		306
362	The global C<$SELF> (exported by this module) contains C<$port> while	307	The global C<$SELF> (exported by this module) contains C<$port> while
363	executing the callback.	308	executing the callback. Runtime errors during callback execution will
		309	result in the port being C<kil>ed.
364		310
365	Runtime errors during callback execution will result in the port being	311	The default callback received all messages not matched by a more specific
366	C<kil>ed.	312	C<tag> match.
367		313
368	If the match is an array reference, then it will be matched against the	314	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
369	first elements of the message, otherwise only the first element is being
370	matched.
371		315
372	Any element in the match that is specified as C<_any_> (a function	316	Register (or replace) callbacks to be called on messages starting with the
373	exported by this module) matches any single element of the message.	317	given tag on the given port (and return the port), or unregister it (when
		318	C<$callback> is C<$undef> or missing). There can only be one callback
		319	registered for each tag.
374		320
375	While not required, it is highly recommended that the first matching	321	The original message will be passed to the callback, after the first
376	element is a string identifying the message. The one-string-only match is	322	element (the tag) has been removed. The callback will use the same
377	also the most efficient match (by far).	323	environment as the default callback (see above).
378		324
379	Example: create a port and bind receivers on it in one go.	325	Example: create a port and bind receivers on it in one go.
380		326
381	my $port = rcv port,	327	my $port = rcv port,
382	msg1 => sub { ...; 0 },	328	msg1 => sub { ... },
383	msg2 => sub { ...; 0 },	329	msg2 => sub { ... },
384	;	330	;
385		331
386	Example: create a port, bind receivers and send it in a message elsewhere	332	Example: create a port, bind receivers and send it in a message elsewhere
387	in one go:	333	in one go:
388		334
389	snd $otherport, reply =>	335	snd $otherport, reply =>
390	rcv port,	336	rcv port,
391	msg1 => sub { ...; 0 },	337	msg1 => sub { ... },
392	...	338	...
393	;	339	;
		340
		341	Example: temporarily register a rcv callback for a tag matching some port
		342	(e.g. for a rpc reply) and unregister it after a message was received.
		343
		344	rcv $port, $otherport => sub {
		345	my @reply = @_;
		346
		347	rcv $SELF, $otherport;
		348	};
394		349
395	=cut	350	=cut
396		351
397	sub rcv($@) {	352	sub rcv($@) {
398	my $port = shift;	353	my $port = shift;
399	my ($noderef, $portid) = split /#/, $port, 2;	354	my ($noderef, $portid) = split /#/, $port, 2;
400		355
401	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	356	$NODE{$noderef} == $NODE{""}
402	or Carp::croak "$port: rcv can only be called on local ports, caught";	357	or Carp::croak "$port: rcv can only be called on local ports, caught";
403		358
404	if (@_ == 1) {	359	while (@_) {
		360	if (ref $_[0]) {
		361	if (my $self = $PORT_DATA{$portid}) {
		362	"AnyEvent::MP::Port" eq ref $self
		363	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		364
		365	$self->[2] = shift;
		366	} else {
405	my $cb = shift;	367	my $cb = shift;
406	delete $PORT_DATA{$portid};
407	$PORT{$portid} = sub {	368	$PORT{$portid} = sub {
408	local $SELF = $port;	369	local $SELF = $port;
409	eval {	370	eval { &$cb }; _self_die if $@;
410	&$cb	371	};
411	and kil $port;
412	};	372	}
413	_self_die if $@;	373	} elsif (defined $_[0]) {
414	};
415	} else {
416	my $self = $PORT_DATA{$portid} \|\|= do {	374	my $self = $PORT_DATA{$portid} \|\|= do {
417	my $self = bless {	375	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
418	id => $port,
419	}, "AnyEvent::MP::Port";
420		376
421	$PORT{$portid} = sub {	377	$PORT{$portid} = sub {
422	local $SELF = $port;	378	local $SELF = $port;
423		379
424	eval {
425	for (@{ $self->{rc0}{$_[0]} }) {	380	if (my $cb = $self->[1]{$_[0]}) {
426	$_ && &{$_->[0]}	381	shift;
427	&& undef $_;	382	eval { &$cb }; _self_die if $@;
428	}	383	} else {
429
430	for (@{ $self->{rcv}{$_[0]} }) {
431	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
432	&& &{$_->[0]}	384	&{ $self->[0] };
433	&& undef $_;
434	}
435
436	for (@{ $self->{any} }) {
437	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
438	&& &{$_->[0]}
439	&& undef $_;
440	}	385	}
441	};	386	};
442	_self_die if $@;	387
		388	$self
443	};	389	};
444		390
445	$self
446	};
447
448	"AnyEvent::MP::Port" eq ref $self	391	"AnyEvent::MP::Port" eq ref $self
449	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	392	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
450		393
451	while (@_) {
452	my ($match, $cb) = splice @_, 0, 2;	394	my ($tag, $cb) = splice @_, 0, 2;
453		395
454	if (!ref $match) {	396	if (defined $cb) {
455	push @{ $self->{rc0}{$match} }, [$cb];	397	$self->[1]{$tag} = $cb;
456	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
457	my ($type, @match) = @$match;
458	@match
459	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
460	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
461	} else {	398	} else {
462	push @{ $self->{any} }, [$cb, $match];	399	delete $self->[1]{$tag};
463	}	400	}
464	}	401	}
465	}	402	}
466		403
467	$port	404	$port
…		…
503	$res	440	$res
504	}	441	}
505	}	442	}
506	}	443	}
507		444
508	=item $guard = mon $port, $cb->(@reason)	445	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
509		446
510	=item $guard = mon $port, $rcvport	447	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
511		448
512	=item $guard = mon $port	449	=item $guard = mon $port # kill $SELF when $port dies
513		450
514	=item $guard = mon $port, $rcvport, @msg	451	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
515		452
516	Monitor the given port and do something when the port is killed or	453	Monitor the given port and do something when the port is killed or
517	messages to it were lost, and optionally return a guard that can be used	454	messages to it were lost, and optionally return a guard that can be used
518	to stop monitoring again.	455	to stop monitoring again.
519		456
520	C<mon> effectively guarantees that, in the absence of hardware failures,	457	C<mon> effectively guarantees that, in the absence of hardware failures,
521	that after starting the monitor, either all messages sent to the port	458	after starting the monitor, either all messages sent to the port will
522	will arrive, or the monitoring action will be invoked after possible	459	arrive, or the monitoring action will be invoked after possible message
523	message loss has been detected. No messages will be lost "in between"	460	loss has been detected. No messages will be lost "in between" (after
524	(after the first lost message no further messages will be received by the	461	the first lost message no further messages will be received by the
525	port). After the monitoring action was invoked, further messages might get	462	port). After the monitoring action was invoked, further messages might get
526	delivered again.	463	delivered again.
		464
		465	Note that monitoring-actions are one-shot: once messages are lost (and a
		466	monitoring alert was raised), they are removed and will not trigger again.
527		467
528	In the first form (callback), the callback is simply called with any	468	In the first form (callback), the callback is simply called with any
529	number of C<@reason> elements (no @reason means that the port was deleted	469	number of C<@reason> elements (no @reason means that the port was deleted
530	"normally"). Note also that I<< the callback B<must> never die >>, so use	470	"normally"). Note also that I<< the callback B<must> never die >>, so use
531	C<eval> if unsure.	471	C<eval> if unsure.
…		…
593	is killed, the references will be freed.	533	is killed, the references will be freed.
594		534
595	Optionally returns a guard that will stop the monitoring.	535	Optionally returns a guard that will stop the monitoring.
596		536
597	This function is useful when you create e.g. timers or other watchers and	537	This function is useful when you create e.g. timers or other watchers and
598	want to free them when the port gets killed:	538	want to free them when the port gets killed (note the use of C<psub>):
599		539
600	$port->rcv (start => sub {	540	$port->rcv (start => sub {
601	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	541	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
602	undef $timer if 0.9 < rand;	542	undef $timer if 0.9 < rand;
603	});	543	});
604	});	544	});
605		545
606	=cut	546	=cut
…		…
615		555
616	=item kil $port[, @reason]	556	=item kil $port[, @reason]
617		557
618	Kill the specified port with the given C<@reason>.	558	Kill the specified port with the given C<@reason>.
619		559
620	If no C<@reason> is specified, then the port is killed "normally" (linked	560	If no C<@reason> is specified, then the port is killed "normally" (ports
621	ports will not be kileld, or even notified).	561	monitoring other ports will not necessarily die because a port dies
		562	"normally").
622		563
623	Otherwise, linked ports get killed with the same reason (second form of	564	Otherwise, linked ports get killed with the same reason (second form of
624	C<mon>, see below).	565	C<mon>, see above).
625		566
626	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	567	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
627	will be reported as reason C<< die => $@ >>.	568	will be reported as reason C<< die => $@ >>.
628		569
629	Transport/communication errors are reported as C<< transport_error =>	570	Transport/communication errors are reported as C<< transport_error =>
…		…
634	=item $port = spawn $node, $initfunc[, @initdata]	575	=item $port = spawn $node, $initfunc[, @initdata]
635		576
636	Creates a port on the node C<$node> (which can also be a port ID, in which	577	Creates a port on the node C<$node> (which can also be a port ID, in which
637	case it's the node where that port resides).	578	case it's the node where that port resides).
638		579
639	The port ID of the newly created port is return immediately, and it is	580	The port ID of the newly created port is returned immediately, and it is
640	permissible to immediately start sending messages or monitor the port.	581	possible to immediately start sending messages or to monitor the port.
641		582
642	After the port has been created, the init function is	583	After the port has been created, the init function is called on the remote
643	called. This function must be a fully-qualified function name	584	node, in the same context as a C<rcv> callback. This function must be a
644	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	585	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
645	program, use C<::name>.	586	specify a function in the main program, use C<::name>.
646		587
647	If the function doesn't exist, then the node tries to C<require>	588	If the function doesn't exist, then the node tries to C<require>
648	the package, then the package above the package and so on (e.g.	589	the package, then the package above the package and so on (e.g.
649	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	590	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
650	exists or it runs out of package names.	591	exists or it runs out of package names.
651		592
652	The init function is then called with the newly-created port as context	593	The init function is then called with the newly-created port as context
653	object (C<$SELF>) and the C<@initdata> values as arguments.	594	object (C<$SELF>) and the C<@initdata> values as arguments.
654		595
655	A common idiom is to pass your own port, monitor the spawned port, and	596	A common idiom is to pass a local port, immediately monitor the spawned
656	in the init function, monitor the original port. This two-way monitoring	597	port, and in the remote init function, immediately monitor the passed
657	ensures that both ports get cleaned up when there is a problem.	598	local port. This two-way monitoring ensures that both ports get cleaned up
		599	when there is a problem.
658		600
659	Example: spawn a chat server port on C<$othernode>.	601	Example: spawn a chat server port on C<$othernode>.
660		602
661	# this node, executed from within a port context:	603	# this node, executed from within a port context:
662	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	604	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
692	my $id = "$RUNIQ." . $ID++;	634	my $id = "$RUNIQ." . $ID++;
693		635
694	$_[0] =~ /::/	636	$_[0] =~ /::/
695	or Carp::croak "spawn init function must be a fully-qualified name, caught";	637	or Carp::croak "spawn init function must be a fully-qualified name, caught";
696		638
697	($NODE{$noderef} \|\| add_node $noderef)	639	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
698	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
699		640
700	"$noderef#$id"	641	"$noderef#$id"
701	}	642	}
702		643
703	=back	644	=item after $timeout, @msg
704		645
705	=head1 NODE MESSAGES	646	=item after $timeout, $callback
706		647
707	Nodes understand the following messages sent to them. Many of them take	648	Either sends the given message, or call the given callback, after the
708	arguments called C<@reply>, which will simply be used to compose a reply	649	specified number of seconds.
709	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
710	the remaining arguments are simply the message data.
711		650
712	While other messages exist, they are not public and subject to change.	651	This is simply a utility function that comes in handy at times - the
		652	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		653	so it may go away in the future.
713		654
714	=over 4
715
716	=cut	655	=cut
717		656
718	=item lookup => $name, @reply	657	sub after($@) {
		658	my ($timeout, @action) = @_;
719		659
720	Replies with the port ID of the specified well-known port, or C<undef>.	660	my $t; $t = AE::timer $timeout, 0, sub {
721		661	undef $t;
722	=item devnull => ...	662	ref $action[0]
723		663	? $action[0]()
724	Generic data sink/CPU heat conversion.	664	: snd @action;
725		665	};
726	=item relay => $port, @msg	666	}
727
728	Simply forwards the message to the given port.
729
730	=item eval => $string[ @reply]
731
732	Evaluates the given string. If C<@reply> is given, then a message of the
733	form C<@reply, $@, @evalres> is sent.
734
735	Example: crash another node.
736
737	snd $othernode, eval => "exit";
738
739	=item time => @reply
740
741	Replies the the current node time to C<@reply>.
742
743	Example: tell the current node to send the current time to C<$myport> in a
744	C<timereply> message.
745
746	snd $NODE, time => $myport, timereply => 1, 2;
747	# => snd $myport, timereply => 1, 2, <time>
748		667
749	=back	668	=back
750		669
751	=head1 AnyEvent::MP vs. Distributed Erlang	670	=head1 AnyEvent::MP vs. Distributed Erlang
752		671
…		…
762		681
763	Despite the similarities, there are also some important differences:	682	Despite the similarities, there are also some important differences:
764		683
765	=over 4	684	=over 4
766		685
767	=item * Node references contain the recipe on how to contact them.	686	=item * Node IDs are arbitrary strings in AEMP.
768		687
769	Erlang relies on special naming and DNS to work everywhere in the	688	Erlang relies on special naming and DNS to work everywhere in the same
770	same way. AEMP relies on each node knowing it's own address(es), with	689	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
771	convenience functionality.	690	configuraiton or DNS), but will otherwise discover other odes itself.
772		691
773	This means that AEMP requires a less tightly controlled environment at the	692	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
774	cost of longer node references and a slightly higher management overhead.	693	uses "local ports are like remote ports".
		694
		695	The failure modes for local ports are quite different (runtime errors
		696	only) then for remote ports - when a local port dies, you I<know> it dies,
		697	when a connection to another node dies, you know nothing about the other
		698	port.
		699
		700	Erlang pretends remote ports are as reliable as local ports, even when
		701	they are not.
		702
		703	AEMP encourages a "treat remote ports differently" philosophy, with local
		704	ports being the special case/exception, where transport errors cannot
		705	occur.
775		706
776	=item * Erlang uses processes and a mailbox, AEMP does not queue.	707	=item * Erlang uses processes and a mailbox, AEMP does not queue.
777		708
778	Erlang uses processes that selctively receive messages, and therefore	709	Erlang uses processes that selectively receive messages, and therefore
779	needs a queue. AEMP is event based, queuing messages would serve no useful	710	needs a queue. AEMP is event based, queuing messages would serve no
780	purpose.	711	useful purpose. For the same reason the pattern-matching abilities of
		712	AnyEvent::MP are more limited, as there is little need to be able to
		713	filter messages without dequeing them.
781		714
782	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	715	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
783		716
784	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	717	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
785		718
786	Sending messages in Erlang is synchronous and blocks the process. AEMP	719	Sending messages in Erlang is synchronous and blocks the process (and
787	sends are immediate, connection establishment is handled in the	720	so does not need a queue that can overflow). AEMP sends are immediate,
788	background.	721	connection establishment is handled in the background.
789		722
790	=item * Erlang can silently lose messages, AEMP cannot.	723	=item * Erlang suffers from silent message loss, AEMP does not.
791		724
792	Erlang makes few guarantees on messages delivery - messages can get lost	725	Erlang makes few guarantees on messages delivery - messages can get lost
793	without any of the processes realising it (i.e. you send messages a, b,	726	without any of the processes realising it (i.e. you send messages a, b,
794	and c, and the other side only receives messages a and c).	727	and c, and the other side only receives messages a and c).
795		728
796	AEMP guarantees correct ordering, and the guarantee that there are no	729	AEMP guarantees correct ordering, and the guarantee that after one message
797	holes in the message sequence.	730	is lost, all following ones sent to the same port are lost as well, until
798		731	monitoring raises an error, so there are no silent "holes" in the message
799	=item * In Erlang, processes can be declared dead and later be found to be	732	sequence.
800	alive.
801
802	In Erlang it can happen that a monitored process is declared dead and
803	linked processes get killed, but later it turns out that the process is
804	still alive - and can receive messages.
805
806	In AEMP, when port monitoring detects a port as dead, then that port will
807	eventually be killed - it cannot happen that a node detects a port as dead
808	and then later sends messages to it, finding it is still alive.
809		733
810	=item * Erlang can send messages to the wrong port, AEMP does not.	734	=item * Erlang can send messages to the wrong port, AEMP does not.
811		735
812	In Erlang it is quite possible that a node that restarts reuses a process	736	In Erlang it is quite likely that a node that restarts reuses a process ID
813	ID known to other nodes for a completely different process, causing	737	known to other nodes for a completely different process, causing messages
814	messages destined for that process to end up in an unrelated process.	738	destined for that process to end up in an unrelated process.
815		739
816	AEMP never reuses port IDs, so old messages or old port IDs floating	740	AEMP never reuses port IDs, so old messages or old port IDs floating
817	around in the network will not be sent to an unrelated port.	741	around in the network will not be sent to an unrelated port.
818		742
819	=item * Erlang uses unprotected connections, AEMP uses secure	743	=item * Erlang uses unprotected connections, AEMP uses secure
820	authentication and can use TLS.	744	authentication and can use TLS.
821		745
822	AEMP can use a proven protocol - SSL/TLS - to protect connections and	746	AEMP can use a proven protocol - TLS - to protect connections and
823	securely authenticate nodes.	747	securely authenticate nodes.
824		748
825	=item * The AEMP protocol is optimised for both text-based and binary	749	=item * The AEMP protocol is optimised for both text-based and binary
826	communications.	750	communications.
827		751
828	The AEMP protocol, unlike the Erlang protocol, supports both	752	The AEMP protocol, unlike the Erlang protocol, supports both programming
829	language-independent text-only protocols (good for debugging) and binary,	753	language independent text-only protocols (good for debugging) and binary,
830	language-specific serialisers (e.g. Storable).	754	language-specific serialisers (e.g. Storable). By default, unless TLS is
		755	used, the protocol is actually completely text-based.
831		756
832	It has also been carefully designed to be implementable in other languages	757	It has also been carefully designed to be implementable in other languages
833	with a minimum of work while gracefully degrading fucntionality to make the	758	with a minimum of work while gracefully degrading functionality to make the
834	protocol simple.	759	protocol simple.
835		760
836	=item * AEMP has more flexible monitoring options than Erlang.	761	=item * AEMP has more flexible monitoring options than Erlang.
837		762
838	In Erlang, you can chose to receive I<all> exit signals as messages	763	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
841	Erlang, as one can choose between automatic kill, exit message or callback	766	Erlang, as one can choose between automatic kill, exit message or callback
842	on a per-process basis.	767	on a per-process basis.
843		768
844	=item * Erlang tries to hide remote/local connections, AEMP does not.	769	=item * Erlang tries to hide remote/local connections, AEMP does not.
845		770
846	Monitoring in Erlang is not an indicator of process death/crashes,	771	Monitoring in Erlang is not an indicator of process death/crashes, in the
847	as linking is (except linking is unreliable in Erlang).	772	same way as linking is (except linking is unreliable in Erlang).
848		773
849	In AEMP, you don't "look up" registered port names or send to named ports	774	In AEMP, you don't "look up" registered port names or send to named ports
850	that might or might not be persistent. Instead, you normally spawn a port	775	that might or might not be persistent. Instead, you normally spawn a port
851	on the remote node. The init function monitors the you, and you monitor	776	on the remote node. The init function monitors you, and you monitor the
852	the remote port. Since both monitors are local to the node, they are much	777	remote port. Since both monitors are local to the node, they are much more
853	more reliable.	778	reliable (no need for C<spawn_link>).
854		779
855	This also saves round-trips and avoids sending messages to the wrong port	780	This also saves round-trips and avoids sending messages to the wrong port
856	(hard to do in Erlang).	781	(hard to do in Erlang).
857		782
858	=back	783	=back
859		784
860	=head1 RATIONALE	785	=head1 RATIONALE
861		786
862	=over 4	787	=over 4
863		788
864	=item Why strings for ports and noderefs, why not objects?	789	=item Why strings for port and node IDs, why not objects?
865		790
866	We considered "objects", but found that the actual number of methods	791	We considered "objects", but found that the actual number of methods
867	thatc an be called are very low. Since port IDs and noderefs travel over	792	that can be called are quite low. Since port and node IDs travel over
868	the network frequently, the serialising/deserialising would add lots of	793	the network frequently, the serialising/deserialising would add lots of
869	overhead, as well as having to keep a proxy object.	794	overhead, as well as having to keep a proxy object everywhere.
870		795
871	Strings can easily be printed, easily serialised etc. and need no special	796	Strings can easily be printed, easily serialised etc. and need no special
872	procedures to be "valid".	797	procedures to be "valid".
873		798
874	And a a miniport consists of a single closure stored in a global hash - it	799	And as a result, a miniport consists of a single closure stored in a
875	can't become much cheaper.	800	global hash - it can't become much cheaper.
876		801
877	=item Why favour JSON, why not real serialising format such as Storable?	802	=item Why favour JSON, why not a real serialising format such as Storable?
878		803
879	In fact, any AnyEvent::MP node will happily accept Storable as framing	804	In fact, any AnyEvent::MP node will happily accept Storable as framing
880	format, but currently there is no way to make a node use Storable by	805	format, but currently there is no way to make a node use Storable by
881	default.	806	default (although all nodes will accept it).
882		807
883	The default framing protocol is JSON because a) JSON::XS is many times	808	The default framing protocol is JSON because a) JSON::XS is many times
884	faster for small messages and b) most importantly, after years of	809	faster for small messages and b) most importantly, after years of
885	experience we found that object serialisation is causing more problems	810	experience we found that object serialisation is causing more problems
886	than it gains: Just like function calls, objects simply do not travel	811	than it solves: Just like function calls, objects simply do not travel
887	easily over the network, mostly because they will always be a copy, so you	812	easily over the network, mostly because they will always be a copy, so you
888	always have to re-think your design.	813	always have to re-think your design.
889		814
890	Keeping your messages simple, concentrating on data structures rather than	815	Keeping your messages simple, concentrating on data structures rather than
891	objects, will keep your messages clean, tidy and efficient.	816	objects, will keep your messages clean, tidy and efficient.
892		817
893	=back	818	=back
894		819
895	=head1 SEE ALSO	820	=head1 SEE ALSO
896		821
		822	L<AnyEvent::MP::Intro> - a gentle introduction.
		823
		824	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		825
		826	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		827	your applications.
		828
897	L<AnyEvent>.	829	L<AnyEvent>.
898		830
899	=head1 AUTHOR	831	=head1 AUTHOR
900		832
901	Marc Lehmann <schmorp@schmorp.de>	833	Marc Lehmann <schmorp@schmorp.de>

Diff Legend

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

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs. Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs.
Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC