[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 1.68 by root, Fri Aug 28 23:06:33 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46	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - outdated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
158		168
159	=item initialise_node "slave/", $master, $master...
160
161	Before a node can talk to other nodes on the network it has to initialise	169	Before a node can talk to other nodes on the network (i.e. enter
162	itself - the minimum a node needs to know is it's own name, and optionally	170	"distributed mode") it has to initialise itself - the minimum a node needs
163	it should know the noderefs of some other nodes in the network.	171	to know is its own name, and optionally it should know the addresses of
		172	some other nodes in the network to discover other nodes.
164		173
165	This function initialises a node - it must be called exactly once (or	174	This function initialises a node - it must be called exactly once (or
166	never) before calling other AnyEvent::MP functions.	175	never) before calling other AnyEvent::MP functions.
167		176
168	All arguments are noderefs, which can be either resolved or unresolved.	177	The first argument is a profile name. If it is C<undef> or missing, then
		178	the current nodename will be used instead (i.e. F<uname -n>).
169		179
170	There are two types of networked nodes, public nodes and slave nodes:	180	The function then looks up the profile in the aemp configuration (see the
		181	L<aemp> commandline utility).
171		182
172	=over 4	183	If the profile specifies a node ID, then this will become the node ID of
		184	this process. If not, then the profile name will be used as node ID. The
		185	special node ID of C<anon/> will be replaced by a random node ID.
173		186
174	=item public nodes	187	The next step is to look up the binds in the profile, followed by binding
		188	aemp protocol listeners on all binds specified (it is possible and valid
		189	to have no binds, meaning that the node cannot be contacted form the
		190	outside. This means the node cannot talk to other nodes that also have no
		191	binds, but it can still talk to all "normal" nodes).
175		192
176	For public nodes, C<$noderef> must either be a (possibly unresolved)	193	If the profile does not specify a binds list, then the node ID will be
177	noderef, in which case it will be resolved, or C<undef> (or missing), in	194	treated as if it were of the form C<host:port>, which will be resolved and
178	which case the noderef will be guessed.	195	used as binds list.
179		196
180	Afterwards, the node will bind itself on all endpoints and try to connect	197	Lastly, the seeds list from the profile is passed to the
181	to all additional C<$seednodes> that are specified. Seednodes are optional	198	L<AnyEvent::MP::Global> module, which will then use it to keep
182	and can be used to quickly bootstrap the node into an existing network.	199	connectivity with at least on of those seed nodes at any point in time.
183		200
184	=item slave nodes	201	Example: become a distributed node listening on the guessed noderef, or
185		202	the one specified via C<aemp> for the current node. This should be the
186	When the C<$noderef> is the special string C<slave/>, then the node will	203	most common form of invocation for "daemon"-type nodes.
187	become a slave node. Slave nodes cannot be contacted from outside and will
188	route most of their traffic to the master node that they attach to.
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		204
202	initialise_node;	205	initialise_node;
203		206
204	Example: become a public node, and try to contact some well-known master	207	Example: become an anonymous node. This form is often used for commandline
205	servers to become part of the network.	208	clients.
206		209
207	initialise_node undef, "master1", "master2";
208
209	Example: become a public node listening on port C<4041>.
210
211	initialise_node 4041;	210	initialise_node "anon/";
212		211
213	Example: become a public node, only visible on localhost port 4044.	212	Example: become a distributed node. If there is no profile of the given
		213	name, or no binds list was specified, resolve C<localhost:4044> and bind
		214	on the resulting addresses.
214		215
215	initialise_node "locahost:4044";	216	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		217
250	=item $SELF	218	=item $SELF
251		219
252	Contains the current port id while executing C<rcv> callbacks or C<psub>	220	Contains the current port id while executing C<rcv> callbacks or C<psub>
253	blocks.	221	blocks.
254		222
255	=item SELF, %SELF, @SELF...	223	=item *SELF, SELF, %SELF, @SELF...
256		224
257	Due to some quirks in how perl exports variables, it is impossible to	225	Due to some quirks in how perl exports variables, it is impossible to
258	just export C<$SELF>, all the symbols called C<SELF> are exported by this	226	just export C<$SELF>, all the symbols named C<SELF> are exported by this
259	module, but only C<$SELF> is currently used.	227	module, but only C<$SELF> is currently used.
260		228
261	=item snd $port, type => @data	229	=item snd $port, type => @data
262		230
263	=item snd $port, @msg	231	=item snd $port, @msg
264		232
265	Send the given message to the given port ID, which can identify either	233	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	234	local or a remote port, and must be a port ID.
267	stringifies a sa port ID (such as a port object :).
268		235
269	While the message can be about anything, it is highly recommended to use a	236	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	237	use a string as first element (a port ID, or some word that indicates a
271	type etc.).	238	request type etc.) and to consist if only simple perl values (scalars,
		239	arrays, hashes) - if you think you need to pass an object, think again.
272		240
273	The message data effectively becomes read-only after a call to this	241	The message data logically becomes read-only after a call to this
274	function: modifying any argument is not allowed and can cause many	242	function: modifying any argument (or values referenced by them) is
275	problems.	243	forbidden, as there can be considerable time between the call to C<snd>
		244	and the time the message is actually being serialised - in fact, it might
		245	never be copied as within the same process it is simply handed to the
		246	receiving port.
276		247
277	The type of data you can transfer depends on the transport protocol: when	248	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	249	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	250	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	251	that Storable can serialise and deserialise is allowed, and for the local
281	node, anything can be passed.	252	node, anything can be passed. Best rely only on the common denominator of
		253	these.
282		254
283	=item $local_port = port	255	=item $local_port = port
284		256
285	Create a new local port object that can be used either as a pattern	257	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"),	258	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		259
289	=item $port = port { my @msg = @_; $finished }	260	=item $local_port = port { my @msg = @_ }
290		261
291	Creates a "miniport", that is, a very lightweight port without any pattern	262	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.	263	creating a port and calling C<rcv $port, $callback> on it.
294		264
295	The block will be called for every message received on the port. When the	265	The block will be called for every message received on the port, with the
296	callback returns a true value its job is considered "done" and the port	266	global variable C<$SELF> set to the port ID. Runtime errors will cause the
297	will be destroyed. Otherwise it will stay alive.	267	port to be C<kil>ed. The message will be passed as-is, no extra argument
		268	(i.e. no port ID) will be passed to the callback.
298		269
299	The message will be passed as-is, no extra argument (i.e. no port id) will	270	If you want to stop/destroy the port, simply C<kil> it:
300	be passed to the callback.
301		271
302	If you need the local port id in the callback, this works nicely:	272	my $port = port {
303		273	my @msg = @_;
304	my $port; $port = port {	274	...
305	snd $otherport, reply => $port;	275	kil $SELF;
306	};	276	};
307		277
308	=cut	278	=cut
309		279
310	sub rcv($@);	280	sub rcv($@);
		281
		282	sub _kilme {
		283	die "received message on port without callback";
		284	}
311		285
312	sub port(;&) {	286	sub port(;&) {
313	my $id = "$UNIQ." . $ID++;	287	my $id = "$UNIQ." . $ID++;
314	my $port = "$NODE#$id";	288	my $port = "$NODE#$id";
315		289
316	if (@_) {	290	rcv $port, shift \|\| \&_kilme;
317	rcv $port, shift;
318	} else {
319	$PORT{$id} = sub { }; # nop
320	}
321		291
322	$port	292	$port
323	}	293	}
324		294
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)	295	=item rcv $local_port, $callback->(@msg)
345		296
346	Replaces the callback on the specified miniport (after converting it to	297	Replaces the default callback on the specified port. There is no way to
347	one if required).	298	remove the default callback: use C<sub { }> to disable it, or better
348		299	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...] => $callback->(@msg), ...
354
355	Register callbacks to be called on matching messages on the given full
356	port (after converting it to one if required) and return the port.
357
358	The callback has to return a true value when its work is done, after
359	which is will be removed, or a false value in which case it will stay
360	registered.
361		300
362	The global C<$SELF> (exported by this module) contains C<$port> while	301	The global C<$SELF> (exported by this module) contains C<$port> while
363	executing the callback.	302	executing the callback. Runtime errors during callback execution will
		303	result in the port being C<kil>ed.
364		304
365	Runtime errors during callback execution will result in the port being	305	The default callback received all messages not matched by a more specific
366	C<kil>ed.	306	C<tag> match.
367		307
368	If the match is an array reference, then it will be matched against the	308	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
369	first elements of the message, otherwise only the first element is being
370	matched.
371		309
372	Any element in the match that is specified as C<_any_> (a function	310	Register (or replace) callbacks to be called on messages starting with the
373	exported by this module) matches any single element of the message.	311	given tag on the given port (and return the port), or unregister it (when
		312	C<$callback> is C<$undef> or missing). There can only be one callback
		313	registered for each tag.
374		314
375	While not required, it is highly recommended that the first matching	315	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	316	element (the tag) has been removed. The callback will use the same
377	also the most efficient match (by far).	317	environment as the default callback (see above).
378		318
379	Example: create a port and bind receivers on it in one go.	319	Example: create a port and bind receivers on it in one go.
380		320
381	my $port = rcv port,	321	my $port = rcv port,
382	msg1 => sub { ...; 0 },	322	msg1 => sub { ... },
383	msg2 => sub { ...; 0 },	323	msg2 => sub { ... },
384	;	324	;
385		325
386	Example: create a port, bind receivers and send it in a message elsewhere	326	Example: create a port, bind receivers and send it in a message elsewhere
387	in one go:	327	in one go:
388		328
389	snd $otherport, reply =>	329	snd $otherport, reply =>
390	rcv port,	330	rcv port,
391	msg1 => sub { ...; 0 },	331	msg1 => sub { ... },
392	...	332	...
393	;	333	;
		334
		335	Example: temporarily register a rcv callback for a tag matching some port
		336	(e.g. for a rpc reply) and unregister it after a message was received.
		337
		338	rcv $port, $otherport => sub {
		339	my @reply = @_;
		340
		341	rcv $SELF, $otherport;
		342	};
394		343
395	=cut	344	=cut
396		345
397	sub rcv($@) {	346	sub rcv($@) {
398	my $port = shift;	347	my $port = shift;
399	my ($noderef, $portid) = split /#/, $port, 2;	348	my ($noderef, $portid) = split /#/, $port, 2;
400		349
401	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	350	$NODE{$noderef} == $NODE{""}
402	or Carp::croak "$port: rcv can only be called on local ports, caught";	351	or Carp::croak "$port: rcv can only be called on local ports, caught";
403		352
404	if (@_ == 1) {	353	while (@_) {
		354	if (ref $_[0]) {
		355	if (my $self = $PORT_DATA{$portid}) {
		356	"AnyEvent::MP::Port" eq ref $self
		357	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		358
		359	$self->[2] = shift;
		360	} else {
405	my $cb = shift;	361	my $cb = shift;
406	delete $PORT_DATA{$portid};
407	$PORT{$portid} = sub {	362	$PORT{$portid} = sub {
408	local $SELF = $port;	363	local $SELF = $port;
409	eval {	364	eval { &$cb }; _self_die if $@;
410	&$cb	365	};
411	and kil $port;
412	};	366	}
413	_self_die if $@;	367	} elsif (defined $_[0]) {
414	};
415	} else {
416	my $self = $PORT_DATA{$portid} \|\|= do {	368	my $self = $PORT_DATA{$portid} \|\|= do {
417	my $self = bless {	369	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
418	id => $port,
419	}, "AnyEvent::MP::Port";
420		370
421	$PORT{$portid} = sub {	371	$PORT{$portid} = sub {
422	local $SELF = $port;	372	local $SELF = $port;
423		373
424	eval {
425	for (@{ $self->{rc0}{$_[0]} }) {	374	if (my $cb = $self->[1]{$_[0]}) {
426	$_ && &{$_->[0]}	375	shift;
427	&& undef $_;	376	eval { &$cb }; _self_die if $@;
428	}	377	} else {
429
430	for (@{ $self->{rcv}{$_[0]} }) {
431	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
432	&& &{$_->[0]}	378	&{ $self->[0] };
433	&& undef $_;
434	}
435
436	for (@{ $self->{any} }) {
437	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
438	&& &{$_->[0]}
439	&& undef $_;
440	}	379	}
441	};	380	};
442	_self_die if $@;	381
		382	$self
443	};	383	};
444		384
445	$self
446	};
447
448	"AnyEvent::MP::Port" eq ref $self	385	"AnyEvent::MP::Port" eq ref $self
449	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	386	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
450		387
451	while (@_) {
452	my ($match, $cb) = splice @_, 0, 2;	388	my ($tag, $cb) = splice @_, 0, 2;
453		389
454	if (!ref $match) {	390	if (defined $cb) {
455	push @{ $self->{rc0}{$match} }, [$cb];	391	$self->[1]{$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 {	392	} else {
462	push @{ $self->{any} }, [$cb, $match];	393	delete $self->[1]{$tag};
463	}	394	}
464	}	395	}
465	}	396	}
466		397
467	$port	398	$port
…		…
503	$res	434	$res
504	}	435	}
505	}	436	}
506	}	437	}
507		438
508	=item $guard = mon $port, $cb->(@reason)	439	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
509		440
510	=item $guard = mon $port, $rcvport	441	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
511		442
512	=item $guard = mon $port	443	=item $guard = mon $port # kill $SELF when $port dies
513		444
514	=item $guard = mon $port, $rcvport, @msg	445	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
515		446
516	Monitor the given port and do something when the port is killed or	447	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	448	messages to it were lost, and optionally return a guard that can be used
518	to stop monitoring again.	449	to stop monitoring again.
519		450
520	C<mon> effectively guarantees that, in the absence of hardware failures,	451	C<mon> effectively guarantees that, in the absence of hardware failures,
521	that after starting the monitor, either all messages sent to the port	452	after starting the monitor, either all messages sent to the port will
522	will arrive, or the monitoring action will be invoked after possible	453	arrive, or the monitoring action will be invoked after possible message
523	message loss has been detected. No messages will be lost "in between"	454	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	455	the first lost message no further messages will be received by the
525	port). After the monitoring action was invoked, further messages might get	456	port). After the monitoring action was invoked, further messages might get
526	delivered again.	457	delivered again.
		458
		459	Note that monitoring-actions are one-shot: once messages are lost (and a
		460	monitoring alert was raised), they are removed and will not trigger again.
527		461
528	In the first form (callback), the callback is simply called with any	462	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	463	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	464	"normally"). Note also that I<< the callback B<must> never die >>, so use
531	C<eval> if unsure.	465	C<eval> if unsure.
…		…
593	is killed, the references will be freed.	527	is killed, the references will be freed.
594		528
595	Optionally returns a guard that will stop the monitoring.	529	Optionally returns a guard that will stop the monitoring.
596		530
597	This function is useful when you create e.g. timers or other watchers and	531	This function is useful when you create e.g. timers or other watchers and
598	want to free them when the port gets killed:	532	want to free them when the port gets killed (note the use of C<psub>):
599		533
600	$port->rcv (start => sub {	534	$port->rcv (start => sub {
601	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	535	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
602	undef $timer if 0.9 < rand;	536	undef $timer if 0.9 < rand;
603	});	537	});
604	});	538	});
605		539
606	=cut	540	=cut
…		…
615		549
616	=item kil $port[, @reason]	550	=item kil $port[, @reason]
617		551
618	Kill the specified port with the given C<@reason>.	552	Kill the specified port with the given C<@reason>.
619		553
620	If no C<@reason> is specified, then the port is killed "normally" (linked	554	If no C<@reason> is specified, then the port is killed "normally" (ports
621	ports will not be kileld, or even notified).	555	monitoring other ports will not necessarily die because a port dies
		556	"normally").
622		557
623	Otherwise, linked ports get killed with the same reason (second form of	558	Otherwise, linked ports get killed with the same reason (second form of
624	C<mon>, see below).	559	C<mon>, see above).
625		560
626	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	561	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
627	will be reported as reason C<< die => $@ >>.	562	will be reported as reason C<< die => $@ >>.
628		563
629	Transport/communication errors are reported as C<< transport_error =>	564	Transport/communication errors are reported as C<< transport_error =>
…		…
634	=item $port = spawn $node, $initfunc[, @initdata]	569	=item $port = spawn $node, $initfunc[, @initdata]
635		570
636	Creates a port on the node C<$node> (which can also be a port ID, in which	571	Creates a port on the node C<$node> (which can also be a port ID, in which
637	case it's the node where that port resides).	572	case it's the node where that port resides).
638		573
639	The port ID of the newly created port is return immediately, and it is	574	The port ID of the newly created port is returned immediately, and it is
640	permissible to immediately start sending messages or monitor the port.	575	possible to immediately start sending messages or to monitor the port.
641		576
642	After the port has been created, the init function is	577	After the port has been created, the init function is called on the remote
643	called. This function must be a fully-qualified function name	578	node, in the same context as a C<rcv> callback. This function must be a
644	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	579	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
645	program, use C<::name>.	580	specify a function in the main program, use C<::name>.
646		581
647	If the function doesn't exist, then the node tries to C<require>	582	If the function doesn't exist, then the node tries to C<require>
648	the package, then the package above the package and so on (e.g.	583	the package, then the package above the package and so on (e.g.
649	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	584	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
650	exists or it runs out of package names.	585	exists or it runs out of package names.
651		586
652	The init function is then called with the newly-created port as context	587	The init function is then called with the newly-created port as context
653	object (C<$SELF>) and the C<@initdata> values as arguments.	588	object (C<$SELF>) and the C<@initdata> values as arguments.
654		589
655	A common idiom is to pass your own port, monitor the spawned port, and	590	A common idiom is to pass a local port, immediately monitor the spawned
656	in the init function, monitor the original port. This two-way monitoring	591	port, and in the remote init function, immediately monitor the passed
657	ensures that both ports get cleaned up when there is a problem.	592	local port. This two-way monitoring ensures that both ports get cleaned up
		593	when there is a problem.
658		594
659	Example: spawn a chat server port on C<$othernode>.	595	Example: spawn a chat server port on C<$othernode>.
660		596
661	# this node, executed from within a port context:	597	# this node, executed from within a port context:
662	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	598	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
692	my $id = "$RUNIQ." . $ID++;	628	my $id = "$RUNIQ." . $ID++;
693		629
694	$_[0] =~ /::/	630	$_[0] =~ /::/
695	or Carp::croak "spawn init function must be a fully-qualified name, caught";	631	or Carp::croak "spawn init function must be a fully-qualified name, caught";
696		632
697	($NODE{$noderef} \|\| add_node $noderef)	633	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
698	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
699		634
700	"$noderef#$id"	635	"$noderef#$id"
701	}	636	}
702		637
703	=back	638	=item after $timeout, @msg
704		639
705	=head1 NODE MESSAGES	640	=item after $timeout, $callback
706		641
707	Nodes understand the following messages sent to them. Many of them take	642	Either sends the given message, or call the given callback, after the
708	arguments called C<@reply>, which will simply be used to compose a reply	643	specified number of seconds.
709	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
710	the remaining arguments are simply the message data.
711		644
712	While other messages exist, they are not public and subject to change.	645	This is simply a utility function that comes in handy at times - the
		646	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		647	so it may go away in the future.
713		648
714	=over 4
715
716	=cut	649	=cut
717		650
718	=item lookup => $name, @reply	651	sub after($@) {
		652	my ($timeout, @action) = @_;
719		653
720	Replies with the port ID of the specified well-known port, or C<undef>.	654	my $t; $t = AE::timer $timeout, 0, sub {
721		655	undef $t;
722	=item devnull => ...	656	ref $action[0]
723		657	? $action[0]()
724	Generic data sink/CPU heat conversion.	658	: snd @action;
725		659	};
726	=item relay => $port, @msg	660	}
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		661
749	=back	662	=back
750		663
751	=head1 AnyEvent::MP vs. Distributed Erlang	664	=head1 AnyEvent::MP vs. Distributed Erlang
752		665
…		…
762		675
763	Despite the similarities, there are also some important differences:	676	Despite the similarities, there are also some important differences:
764		677
765	=over 4	678	=over 4
766		679
767	=item * Node references contain the recipe on how to contact them.	680	=item * Node IDs are arbitrary strings in AEMP.
768		681
769	Erlang relies on special naming and DNS to work everywhere in the	682	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	683	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
771	convenience functionality.	684	configuraiton or DNS), but will otherwise discover other odes itself.
772		685
773	This means that AEMP requires a less tightly controlled environment at the	686	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
774	cost of longer node references and a slightly higher management overhead.	687	uses "local ports are like remote ports".
		688
		689	The failure modes for local ports are quite different (runtime errors
		690	only) then for remote ports - when a local port dies, you I<know> it dies,
		691	when a connection to another node dies, you know nothing about the other
		692	port.
		693
		694	Erlang pretends remote ports are as reliable as local ports, even when
		695	they are not.
		696
		697	AEMP encourages a "treat remote ports differently" philosophy, with local
		698	ports being the special case/exception, where transport errors cannot
		699	occur.
775		700
776	=item * Erlang uses processes and a mailbox, AEMP does not queue.	701	=item * Erlang uses processes and a mailbox, AEMP does not queue.
777		702
778	Erlang uses processes that selctively receive messages, and therefore	703	Erlang uses processes that selectively receive messages, and therefore
779	needs a queue. AEMP is event based, queuing messages would serve no useful	704	needs a queue. AEMP is event based, queuing messages would serve no
780	purpose.	705	useful purpose. For the same reason the pattern-matching abilities of
		706	AnyEvent::MP are more limited, as there is little need to be able to
		707	filter messages without dequeing them.
781		708
782	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	709	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
783		710
784	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	711	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
785		712
786	Sending messages in Erlang is synchronous and blocks the process. AEMP	713	Sending messages in Erlang is synchronous and blocks the process (and
787	sends are immediate, connection establishment is handled in the	714	so does not need a queue that can overflow). AEMP sends are immediate,
788	background.	715	connection establishment is handled in the background.
789		716
790	=item * Erlang can silently lose messages, AEMP cannot.	717	=item * Erlang suffers from silent message loss, AEMP does not.
791		718
792	Erlang makes few guarantees on messages delivery - messages can get lost	719	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,	720	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).	721	and c, and the other side only receives messages a and c).
795		722
796	AEMP guarantees correct ordering, and the guarantee that there are no	723	AEMP guarantees correct ordering, and the guarantee that after one message
797	holes in the message sequence.	724	is lost, all following ones sent to the same port are lost as well, until
798		725	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	726	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		727
810	=item * Erlang can send messages to the wrong port, AEMP does not.	728	=item * Erlang can send messages to the wrong port, AEMP does not.
811		729
812	In Erlang it is quite possible that a node that restarts reuses a process	730	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	731	known to other nodes for a completely different process, causing messages
814	messages destined for that process to end up in an unrelated process.	732	destined for that process to end up in an unrelated process.
815		733
816	AEMP never reuses port IDs, so old messages or old port IDs floating	734	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.	735	around in the network will not be sent to an unrelated port.
818		736
819	=item * Erlang uses unprotected connections, AEMP uses secure	737	=item * Erlang uses unprotected connections, AEMP uses secure
820	authentication and can use TLS.	738	authentication and can use TLS.
821		739
822	AEMP can use a proven protocol - SSL/TLS - to protect connections and	740	AEMP can use a proven protocol - TLS - to protect connections and
823	securely authenticate nodes.	741	securely authenticate nodes.
824		742
825	=item * The AEMP protocol is optimised for both text-based and binary	743	=item * The AEMP protocol is optimised for both text-based and binary
826	communications.	744	communications.
827		745
828	The AEMP protocol, unlike the Erlang protocol, supports both	746	The AEMP protocol, unlike the Erlang protocol, supports both programming
829	language-independent text-only protocols (good for debugging) and binary,	747	language independent text-only protocols (good for debugging) and binary,
830	language-specific serialisers (e.g. Storable).	748	language-specific serialisers (e.g. Storable). By default, unless TLS is
		749	used, the protocol is actually completely text-based.
831		750
832	It has also been carefully designed to be implementable in other languages	751	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	752	with a minimum of work while gracefully degrading functionality to make the
834	protocol simple.	753	protocol simple.
835		754
836	=item * AEMP has more flexible monitoring options than Erlang.	755	=item * AEMP has more flexible monitoring options than Erlang.
837		756
838	In Erlang, you can chose to receive I<all> exit signals as messages	757	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	760	Erlang, as one can choose between automatic kill, exit message or callback
842	on a per-process basis.	761	on a per-process basis.
843		762
844	=item * Erlang tries to hide remote/local connections, AEMP does not.	763	=item * Erlang tries to hide remote/local connections, AEMP does not.
845		764
846	Monitoring in Erlang is not an indicator of process death/crashes,	765	Monitoring in Erlang is not an indicator of process death/crashes, in the
847	as linking is (except linking is unreliable in Erlang).	766	same way as linking is (except linking is unreliable in Erlang).
848		767
849	In AEMP, you don't "look up" registered port names or send to named ports	768	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	769	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	770	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	771	remote port. Since both monitors are local to the node, they are much more
853	more reliable.	772	reliable (no need for C<spawn_link>).
854		773
855	This also saves round-trips and avoids sending messages to the wrong port	774	This also saves round-trips and avoids sending messages to the wrong port
856	(hard to do in Erlang).	775	(hard to do in Erlang).
857		776
858	=back	777	=back
859		778
860	=head1 RATIONALE	779	=head1 RATIONALE
861		780
862	=over 4	781	=over 4
863		782
864	=item Why strings for ports and noderefs, why not objects?	783	=item Why strings for port and node IDs, why not objects?
865		784
866	We considered "objects", but found that the actual number of methods	785	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	786	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	787	the network frequently, the serialising/deserialising would add lots of
869	overhead, as well as having to keep a proxy object.	788	overhead, as well as having to keep a proxy object everywhere.
870		789
871	Strings can easily be printed, easily serialised etc. and need no special	790	Strings can easily be printed, easily serialised etc. and need no special
872	procedures to be "valid".	791	procedures to be "valid".
873		792
874	And a a miniport consists of a single closure stored in a global hash - it	793	And as a result, a miniport consists of a single closure stored in a
875	can't become much cheaper.	794	global hash - it can't become much cheaper.
876		795
877	=item Why favour JSON, why not real serialising format such as Storable?	796	=item Why favour JSON, why not a real serialising format such as Storable?
878		797
879	In fact, any AnyEvent::MP node will happily accept Storable as framing	798	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	799	format, but currently there is no way to make a node use Storable by
881	default.	800	default (although all nodes will accept it).
882		801
883	The default framing protocol is JSON because a) JSON::XS is many times	802	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	803	faster for small messages and b) most importantly, after years of
885	experience we found that object serialisation is causing more problems	804	experience we found that object serialisation is causing more problems
886	than it gains: Just like function calls, objects simply do not travel	805	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	806	easily over the network, mostly because they will always be a copy, so you
888	always have to re-think your design.	807	always have to re-think your design.
889		808
890	Keeping your messages simple, concentrating on data structures rather than	809	Keeping your messages simple, concentrating on data structures rather than
891	objects, will keep your messages clean, tidy and efficient.	810	objects, will keep your messages clean, tidy and efficient.
892		811
893	=back	812	=back
894		813
895	=head1 SEE ALSO	814	=head1 SEE ALSO
896		815
		816	L<AnyEvent::MP::Intro> - a gentle introduction.
		817
		818	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		819
		820	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		821	your applications.
		822
897	L<AnyEvent>.	823	L<AnyEvent>.
898		824
899	=head1 AUTHOR	825	=head1 AUTHOR
900		826
901	Marc Lehmann <schmorp@schmorp.de>	827	Marc Lehmann <schmorp@schmorp.de>

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Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs.
Revision 1.68 by root, Fri Aug 28 23:06:33 2009 UTC