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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.45 by root, Thu Aug 13 01:16:24 2009 UTC vs.
Revision 1.79 by root, Fri Sep 4 21:52:09 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
13	$SELF # receiving/own port id in rcv callbacks	12	$SELF # receiving/own port id in rcv callbacks
14		13
		14	# initialise the node so it can send/receive messages
		15	configure;
		16
15	# ports are message endpoints	17	# ports are message destinations
16		18
17	# sending messages	19	# sending messages
18	snd $port, type => data...;	20	snd $port, type => data...;
19	snd $port, @msg;	21	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
21		23
22	# miniports	24	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
24		26
25	# full ports	27	# creating/using ports, tagged message matching
26	my $port = port;	28	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
30		31
31	# remote ports	32	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	33	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		34
38	# monitoring	35	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	36	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
42		39
43	=head1 CURRENT STATUS	40	=head1 CURRENT STATUS
44		41
		42	bin/aemp - stable.
45	AnyEvent::MP - stable API, should work	43	AnyEvent::MP - stable API, should work.
46	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - explains most concepts.
47	AnyEvent::MP::Kernel - WIP
48	AnyEvent::MP::Transport - mostly stable	45	AnyEvent::MP::Kernel - mostly stable.
		46	AnyEvent::MP::Global - stable but incomplete, protocol not yet final.
49		47
50	stay tuned.	48	stay tuned.
51		49
52	=head1 DESCRIPTION	50	=head1 DESCRIPTION
53		51
54	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
55		53
56	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
57	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
58		56
59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	57	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
60	manual page.	58	manual page and the examples under F<eg/>.
61
62	At the moment, this module family is severly broken and underdocumented,
63	so do not use. This was uploaded mainly to reserve the CPAN namespace -
64	stay tuned!
65		59
66	=head1 CONCEPTS	60	=head1 CONCEPTS
67		61
68	=over 4	62	=over 4
69		63
70	=item port	64	=item port
71		65
72	A port is something you can send messages to (with the C<snd> function).	66	Not to be confused with a TCP port, a "port" is something you can send
		67	messages to (with the C<snd> function).
73		68
74	Some ports allow you to register C<rcv> handlers that can match specific	69	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	70	some messages. Messages send to ports will not be queued, regardless of
76	will not be queued.	71	anything was listening for them or not.
77		72
78	=item port id - C<noderef#portname>	73	=item port ID - C<nodeid#portname>
79		74
80	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	75	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	76	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		77
85	=item node	78	=item node
86		79
87	A node is a single process containing at least one port - the node	80	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	81	which enables nodes to manage each other remotely, and to create new
89	create new ports, among other things.	82	ports.
90		83
91	Nodes are either private (single-process only), slaves (connected to a	84	Nodes are either public (have one or more listening ports) or private
92	master node only) or public nodes (connectable from unrelated nodes).	85	(no listening ports). Private nodes cannot talk to other private nodes
		86	currently.
93		87
94	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	88	=item node ID - C<[a-za-Z0-9_\-.:]+>
95		89
96	A node reference is a string that either simply identifies the node (for	90	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	91	network. Depending on the configuration used, node IDs can look like a
98	node (for public nodes).	92	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		93	doesn't interpret node IDs in any way.
99		94
100	This recipe is simply a comma-separated list of C<address:port> pairs (for	95	=item binds - C<ip:port>
101	TCP/IP, other protocols might look different).
102		96
103	Node references come in two flavours: resolved (containing only numerical	97	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).	98	each other. To do this, nodes should listen on one or more local transport
		99	endpoints - binds. Currently, only standard C<ip:port> specifications can
		100	be used, which specify TCP ports to listen on.
105		101
106	Before using an unresolved node reference in a message you first have to	102	=item seeds - C<host:port>
107	resolve it.	103
		104	When a node starts, it knows nothing about the network. To teach the node
		105	about the network it first has to contact some other node within the
		106	network. This node is called a seed.
		107
		108	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		109	are expected to be long-running, and at least one of those should always
		110	be available. When nodes run out of connections (e.g. due to a network
		111	error), they try to re-establish connections to some seednodes again to
		112	join the network.
		113
		114	Apart from being sued for seeding, seednodes are not special in any way -
		115	every public node can be a seednode.
108		116
109	=back	117	=back
110		118
111	=head1 VARIABLES/FUNCTIONS	119	=head1 VARIABLES/FUNCTIONS
112		120
…		…
127	use base "Exporter";	135	use base "Exporter";
128		136
129	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	137	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
130		138
131	our @EXPORT = qw(	139	our @EXPORT = qw(
132	NODE $NODE *SELF node_of _any_	140	NODE $NODE *SELF node_of after
133	resolve_node initialise_node	141	configure
134	snd rcv mon kil reg psub spawn	142	snd rcv mon mon_guard kil reg psub spawn
135	port	143	port
136	);	144	);
137		145
138	our $SELF;	146	our $SELF;
139		147
…		…
143	kil $SELF, die => $msg;	151	kil $SELF, die => $msg;
144	}	152	}
145		153
146	=item $thisnode = NODE / $NODE	154	=item $thisnode = NODE / $NODE
147		155
148	The C<NODE> function returns, and the C<$NODE> variable contains	156	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	157	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	158	a call to C<configure>.
151	identifiers become invalid.
152		159
153	=item $noderef = node_of $port	160	=item $nodeid = node_of $port
154		161
155	Extracts and returns the noderef from a portid or a noderef.	162	Extracts and returns the node ID from a port ID or a node ID.
156		163
157	=item initialise_node $noderef, $seednode, $seednode...	164	=item configure $profile, key => value...
158		165
159	=item initialise_node "slave/", $master, $master...	166	=item configure key => value...
160		167
161	Before a node can talk to other nodes on the network it has to initialise	168	Before a node can talk to other nodes on the network (i.e. enter
162	itself - the minimum a node needs to know is it's own name, and optionally	169	"distributed mode") it has to configure itself - the minimum a node needs
163	it should know the noderefs of some other nodes in the network.	170	to know is its own name, and optionally it should know the addresses of
		171	some other nodes in the network to discover other nodes.
164		172
165	This function initialises a node - it must be called exactly once (or	173	This function configures a node - it must be called exactly once (or
166	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
167		175
168	All arguments are noderefs, which can be either resolved or unresolved.
169
170	There are two types of networked nodes, public nodes and slave nodes:
171
172	=over 4	176	=over 4
173		177
174	=item public nodes	178	=item step 1, gathering configuration from profiles
175		179
176	For public nodes, C<$noderef> must either be a (possibly unresolved)	180	The function first looks up a profile in the aemp configuration (see the
177	noderef, in which case it will be resolved, or C<undef> (or missing), in	181	L<aemp> commandline utility). The profile name can be specified via the
178	which case the noderef will be guessed.	182	named C<profile> parameter or can simply be the first parameter). If it is
		183	missing, then the nodename (F<uname -n>) will be used as profile name.
179		184
180	Afterwards, the node will bind itself on all endpoints and try to connect	185	The profile data is then gathered as follows:
181	to all additional C<$seednodes> that are specified. Seednodes are optional
182	and can be used to quickly bootstrap the node into an existing network.
183		186
184	=item slave nodes	187	First, all remaining key => value pairs (all of which are conveniently
		188	undocumented at the moment) will be interpreted as configuration
		189	data. Then they will be overwritten by any values specified in the global
		190	default configuration (see the F<aemp> utility), then the chain of
		191	profiles chosen by the profile name (and any C<parent> attributes).
185		192
186	When the C<$noderef> is the special string C<slave/>, then the node will	193	That means that the values specified in the profile have highest priority
187	become a slave node. Slave nodes cannot be contacted from outside and will	194	and the values specified directly via C<configure> have lowest priority,
188	route most of their traffic to the master node that they attach to.	195	and can only be used to specify defaults.
189		196
190	At least one additional noderef is required: The node will try to connect	197	If the profile specifies a node ID, then this will become the node ID of
191	to all of them and will become a slave attached to the first node it can	198	this process. If not, then the profile name will be used as node ID. The
192	successfully connect to.	199	special node ID of C<anon/> will be replaced by a random node ID.
		200
		201	=item step 2, bind listener sockets
		202
		203	The next step is to look up the binds in the profile, followed by binding
		204	aemp protocol listeners on all binds specified (it is possible and valid
		205	to have no binds, meaning that the node cannot be contacted form the
		206	outside. This means the node cannot talk to other nodes that also have no
		207	binds, but it can still talk to all "normal" nodes).
		208
		209	If the profile does not specify a binds list, then a default of C<*> is
		210	used, meaning the node will bind on a dynamically-assigned port on every
		211	local IP address it finds.
		212
		213	=item step 3, connect to seed nodes
		214
		215	As the last step, the seeds list from the profile is passed to the
		216	L<AnyEvent::MP::Global> module, which will then use it to keep
		217	connectivity with at least one node at any point in time.
193		218
194	=back	219	=back
195		220
196	This function will block until all nodes have been resolved and, for slave	221	Example: become a distributed node using the locla node name as profile.
197	nodes, until it has successfully established a connection to a master	222	This should be the most common form of invocation for "daemon"-type nodes.
198	server.
199		223
200	Example: become a public node listening on the default node.	224	configure
201		225
202	initialise_node;	226	Example: become an anonymous node. This form is often used for commandline
		227	clients.
203		228
204	Example: become a public node, and try to contact some well-known master	229	configure nodeid => "anon/";
205	servers to become part of the network.
206		230
207	initialise_node undef, "master1", "master2";	231	Example: configure a node using a profile called seed, which si suitable
		232	for a seed node as it binds on all local addresses on a fixed port (4040,
		233	customary for aemp).
208		234
209	Example: become a public node listening on port C<4041>.	235	# use the aemp commandline utility
		236	# aemp profile seed nodeid anon/ binds '*:4040'
210		237
211	initialise_node 4041;	238	# then use it
		239	configure profile => "seed";
212		240
213	Example: become a public node, only visible on localhost port 4044.	241	# or simply use aemp from the shell again:
		242	# aemp run profile seed
214		243
215	initialise_node "locahost:4044";	244	# or provide a nicer-to-remember nodeid
216		245	# aemp run profile seed nodeid "$(hostname)"
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		246
250	=item $SELF	247	=item $SELF
251		248
252	Contains the current port id while executing C<rcv> callbacks or C<psub>	249	Contains the current port id while executing C<rcv> callbacks or C<psub>
253	blocks.	250	blocks.
254		251
255	=item SELF, %SELF, @SELF...	252	=item *SELF, SELF, %SELF, @SELF...
256		253
257	Due to some quirks in how perl exports variables, it is impossible to	254	Due to some quirks in how perl exports variables, it is impossible to
258	just export C<$SELF>, all the symbols called C<SELF> are exported by this	255	just export C<$SELF>, all the symbols named C<SELF> are exported by this
259	module, but only C<$SELF> is currently used.	256	module, but only C<$SELF> is currently used.
260		257
261	=item snd $port, type => @data	258	=item snd $port, type => @data
262		259
263	=item snd $port, @msg	260	=item snd $port, @msg
264		261
265	Send the given message to the given port ID, which can identify either	262	Send the given message to the given port, which can identify either a
266	a local or a remote port, and can be either a string or soemthignt hat	263	local or a remote port, and must be a port ID.
267	stringifies a sa port ID (such as a port object :).
268		264
269	While the message can be about anything, it is highly recommended to use a	265	While the message can be almost anything, it is highly recommended to
270	string as first element (a portid, or some word that indicates a request	266	use a string as first element (a port ID, or some word that indicates a
271	type etc.).	267	request type etc.) and to consist if only simple perl values (scalars,
		268	arrays, hashes) - if you think you need to pass an object, think again.
272		269
273	The message data effectively becomes read-only after a call to this	270	The message data logically becomes read-only after a call to this
274	function: modifying any argument is not allowed and can cause many	271	function: modifying any argument (or values referenced by them) is
275	problems.	272	forbidden, as there can be considerable time between the call to C<snd>
		273	and the time the message is actually being serialised - in fact, it might
		274	never be copied as within the same process it is simply handed to the
		275	receiving port.
276		276
277	The type of data you can transfer depends on the transport protocol: when	277	The type of data you can transfer depends on the transport protocol: when
278	JSON is used, then only strings, numbers and arrays and hashes consisting	278	JSON is used, then only strings, numbers and arrays and hashes consisting
279	of those are allowed (no objects). When Storable is used, then anything	279	of those are allowed (no objects). When Storable is used, then anything
280	that Storable can serialise and deserialise is allowed, and for the local	280	that Storable can serialise and deserialise is allowed, and for the local
281	node, anything can be passed.	281	node, anything can be passed. Best rely only on the common denominator of
		282	these.
282		283
283	=item $local_port = port	284	=item $local_port = port
284		285
285	Create a new local port object that can be used either as a pattern	286	Create a new local port object and returns its port ID. Initially it has
286	matching port ("full port") or a single-callback port ("miniport"),	287	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		288
289	=item $port = port { my @msg = @_; $finished }	289	=item $local_port = port { my @msg = @_ }
290		290
291	Creates a "miniport", that is, a very lightweight port without any pattern	291	Creates a new local port, and returns its ID. Semantically the same as
292	matching behind it, and returns its ID. Semantically the same as creating
293	a port and calling C<rcv $port, $callback> on it.	292	creating a port and calling C<rcv $port, $callback> on it.
294		293
295	The block will be called for every message received on the port. When the	294	The block will be called for every message received on the port, with the
296	callback returns a true value its job is considered "done" and the port	295	global variable C<$SELF> set to the port ID. Runtime errors will cause the
297	will be destroyed. Otherwise it will stay alive.	296	port to be C<kil>ed. The message will be passed as-is, no extra argument
		297	(i.e. no port ID) will be passed to the callback.
298		298
299	The message will be passed as-is, no extra argument (i.e. no port id) will	299	If you want to stop/destroy the port, simply C<kil> it:
300	be passed to the callback.
301		300
302	If you need the local port id in the callback, this works nicely:	301	my $port = port {
303		302	my @msg = @_;
304	my $port; $port = port {	303	...
305	snd $otherport, reply => $port;	304	kil $SELF;
306	};	305	};
307		306
308	=cut	307	=cut
309		308
310	sub rcv($@);	309	sub rcv($@);
		310
		311	sub _kilme {
		312	die "received message on port without callback";
		313	}
311		314
312	sub port(;&) {	315	sub port(;&) {
313	my $id = "$UNIQ." . $ID++;	316	my $id = "$UNIQ." . $ID++;
314	my $port = "$NODE#$id";	317	my $port = "$NODE#$id";
315		318
316	if (@_) {	319	rcv $port, shift \|\| \&_kilme;
317	rcv $port, shift;
318	} else {
319	$PORT{$id} = sub { }; # nop
320	}
321		320
322	$port	321	$port
323	}	322	}
324		323
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)	324	=item rcv $local_port, $callback->(@msg)
345		325
346	Replaces the callback on the specified miniport (after converting it to	326	Replaces the default callback on the specified port. There is no way to
347	one if required).	327	remove the default callback: use C<sub { }> to disable it, or better
348		328	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...] => $callback->(@msg), ...
354
355	Register callbacks to be called on matching messages on the given full
356	port (after converting it to one if required) and return the port.
357
358	The callback has to return a true value when its work is done, after
359	which is will be removed, or a false value in which case it will stay
360	registered.
361		329
362	The global C<$SELF> (exported by this module) contains C<$port> while	330	The global C<$SELF> (exported by this module) contains C<$port> while
363	executing the callback.	331	executing the callback. Runtime errors during callback execution will
		332	result in the port being C<kil>ed.
364		333
365	Runtime errors during callback execution will result in the port being	334	The default callback received all messages not matched by a more specific
366	C<kil>ed.	335	C<tag> match.
367		336
368	If the match is an array reference, then it will be matched against the	337	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
369	first elements of the message, otherwise only the first element is being
370	matched.
371		338
372	Any element in the match that is specified as C<_any_> (a function	339	Register (or replace) callbacks to be called on messages starting with the
373	exported by this module) matches any single element of the message.	340	given tag on the given port (and return the port), or unregister it (when
		341	C<$callback> is C<$undef> or missing). There can only be one callback
		342	registered for each tag.
374		343
375	While not required, it is highly recommended that the first matching	344	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	345	element (the tag) has been removed. The callback will use the same
377	also the most efficient match (by far).	346	environment as the default callback (see above).
378		347
379	Example: create a port and bind receivers on it in one go.	348	Example: create a port and bind receivers on it in one go.
380		349
381	my $port = rcv port,	350	my $port = rcv port,
382	msg1 => sub { ...; 0 },	351	msg1 => sub { ... },
383	msg2 => sub { ...; 0 },	352	msg2 => sub { ... },
384	;	353	;
385		354
386	Example: create a port, bind receivers and send it in a message elsewhere	355	Example: create a port, bind receivers and send it in a message elsewhere
387	in one go:	356	in one go:
388		357
389	snd $otherport, reply =>	358	snd $otherport, reply =>
390	rcv port,	359	rcv port,
391	msg1 => sub { ...; 0 },	360	msg1 => sub { ... },
392	...	361	...
393	;	362	;
394		363
		364	Example: temporarily register a rcv callback for a tag matching some port
		365	(e.g. for a rpc reply) and unregister it after a message was received.
		366
		367	rcv $port, $otherport => sub {
		368	my @reply = @_;
		369
		370	rcv $SELF, $otherport;
		371	};
		372
395	=cut	373	=cut
396		374
397	sub rcv($@) {	375	sub rcv($@) {
398	my $port = shift;	376	my $port = shift;
399	my ($noderef, $portid) = split /#/, $port, 2;	377	my ($nodeid, $portid) = split /#/, $port, 2;
400		378
401	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	379	$NODE{$nodeid} == $NODE{""}
402	or Carp::croak "$port: rcv can only be called on local ports, caught";	380	or Carp::croak "$port: rcv can only be called on local ports, caught";
403		381
404	if (@_ == 1) {	382	while (@_) {
		383	if (ref $_[0]) {
		384	if (my $self = $PORT_DATA{$portid}) {
		385	"AnyEvent::MP::Port" eq ref $self
		386	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		387
		388	$self->[2] = shift;
		389	} else {
405	my $cb = shift;	390	my $cb = shift;
406	delete $PORT_DATA{$portid};
407	$PORT{$portid} = sub {	391	$PORT{$portid} = sub {
408	local $SELF = $port;	392	local $SELF = $port;
409	eval {	393	eval { &$cb }; _self_die if $@;
410	&$cb	394	};
411	and kil $port;
412	};	395	}
413	_self_die if $@;	396	} elsif (defined $_[0]) {
414	};
415	} else {
416	my $self = $PORT_DATA{$portid} \|\|= do {	397	my $self = $PORT_DATA{$portid} \|\|= do {
417	my $self = bless {	398	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
418	id => $port,
419	}, "AnyEvent::MP::Port";
420		399
421	$PORT{$portid} = sub {	400	$PORT{$portid} = sub {
422	local $SELF = $port;	401	local $SELF = $port;
423		402
424	eval {
425	for (@{ $self->{rc0}{$_[0]} }) {	403	if (my $cb = $self->[1]{$_[0]}) {
426	$_ && &{$_->[0]}	404	shift;
427	&& undef $_;	405	eval { &$cb }; _self_die if $@;
428	}	406	} else {
429
430	for (@{ $self->{rcv}{$_[0]} }) {
431	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
432	&& &{$_->[0]}	407	&{ $self->[0] };
433	&& undef $_;
434	}
435
436	for (@{ $self->{any} }) {
437	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
438	&& &{$_->[0]}
439	&& undef $_;
440	}	408	}
441	};	409	};
442	_self_die if $@;	410
		411	$self
443	};	412	};
444		413
445	$self
446	};
447
448	"AnyEvent::MP::Port" eq ref $self	414	"AnyEvent::MP::Port" eq ref $self
449	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	415	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
450		416
451	while (@_) {
452	my ($match, $cb) = splice @_, 0, 2;	417	my ($tag, $cb) = splice @_, 0, 2;
453		418
454	if (!ref $match) {	419	if (defined $cb) {
455	push @{ $self->{rc0}{$match} }, [$cb];	420	$self->[1]{$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 {	421	} else {
462	push @{ $self->{any} }, [$cb, $match];	422	delete $self->[1]{$tag};
463	}	423	}
464	}	424	}
465	}	425	}
466		426
467	$port	427	$port
…		…
503	$res	463	$res
504	}	464	}
505	}	465	}
506	}	466	}
507		467
508	=item $guard = mon $port, $cb->(@reason)	468	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
509		469
510	=item $guard = mon $port, $rcvport	470	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
511		471
512	=item $guard = mon $port	472	=item $guard = mon $port # kill $SELF when $port dies
513		473
514	=item $guard = mon $port, $rcvport, @msg	474	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
515		475
516	Monitor the given port and do something when the port is killed or	476	Monitor the given port and do something when the port is killed or
517	messages to it were lost, and optionally return a guard that can be used	477	messages to it were lost, and optionally return a guard that can be used
518	to stop monitoring again.	478	to stop monitoring again.
519
520	C<mon> effectively guarantees that, in the absence of hardware failures,
521	that after starting the monitor, either all messages sent to the port
522	will arrive, or the monitoring action will be invoked after possible
523	message loss has been detected. No messages will be lost "in between"
524	(after the first lost message no further messages will be received by the
525	port). After the monitoring action was invoked, further messages might get
526	delivered again.
527		479
528	In the first form (callback), the callback is simply called with any	480	In the first form (callback), the callback is simply called with any
529	number of C<@reason> elements (no @reason means that the port was deleted	481	number of C<@reason> elements (no @reason means that the port was deleted
530	"normally"). Note also that I<< the callback B<must> never die >>, so use	482	"normally"). Note also that I<< the callback B<must> never die >>, so use
531	C<eval> if unsure.	483	C<eval> if unsure.
532		484
533	In the second form (another port given), the other port (C<$rcvport>)	485	In the second form (another port given), the other port (C<$rcvport>)
534	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	486	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
535	"normal" kils nothing happens, while under all other conditions, the other	487	"normal" kils nothing happens, while under all other conditions, the other
536	port is killed with the same reason.	488	port is killed with the same reason.
537		489
538	The third form (kill self) is the same as the second form, except that	490	The third form (kill self) is the same as the second form, except that
539	C<$rvport> defaults to C<$SELF>.	491	C<$rvport> defaults to C<$SELF>.
540		492
541	In the last form (message), a message of the form C<@msg, @reason> will be	493	In the last form (message), a message of the form C<@msg, @reason> will be
542	C<snd>.	494	C<snd>.
		495
		496	Monitoring-actions are one-shot: once messages are lost (and a monitoring
		497	alert was raised), they are removed and will not trigger again.
543		498
544	As a rule of thumb, monitoring requests should always monitor a port from	499	As a rule of thumb, monitoring requests should always monitor a port from
545	a local port (or callback). The reason is that kill messages might get	500	a local port (or callback). The reason is that kill messages might get
546	lost, just like any other message. Another less obvious reason is that	501	lost, just like any other message. Another less obvious reason is that
547	even monitoring requests can get lost (for exmaple, when the connection	502	even monitoring requests can get lost (for example, when the connection
548	to the other node goes down permanently). When monitoring a port locally	503	to the other node goes down permanently). When monitoring a port locally
549	these problems do not exist.	504	these problems do not exist.
550		505
		506	C<mon> effectively guarantees that, in the absence of hardware failures,
		507	after starting the monitor, either all messages sent to the port will
		508	arrive, or the monitoring action will be invoked after possible message
		509	loss has been detected. No messages will be lost "in between" (after
		510	the first lost message no further messages will be received by the
		511	port). After the monitoring action was invoked, further messages might get
		512	delivered again.
		513
		514	Inter-host-connection timeouts and monitoring depend on the transport
		515	used. The only transport currently implemented is TCP, and AnyEvent::MP
		516	relies on TCP to detect node-downs (this can take 10-15 minutes on a
		517	non-idle connection, and usually around two hours for idle conenctions).
		518
		519	This means that monitoring is good for program errors and cleaning up
		520	stuff eventually, but they are no replacement for a timeout when you need
		521	to ensure some maximum latency.
		522
551	Example: call a given callback when C<$port> is killed.	523	Example: call a given callback when C<$port> is killed.
552		524
553	mon $port, sub { warn "port died because of <@_>\n" };	525	mon $port, sub { warn "port died because of <@_>\n" };
554		526
555	Example: kill ourselves when C<$port> is killed abnormally.	527	Example: kill ourselves when C<$port> is killed abnormally.
…		…
561	mon $port, $self => "restart";	533	mon $port, $self => "restart";
562		534
563	=cut	535	=cut
564		536
565	sub mon {	537	sub mon {
566	my ($noderef, $port) = split /#/, shift, 2;	538	my ($nodeid, $port) = split /#/, shift, 2;
567		539
568	my $node = $NODE{$noderef} \|\| add_node $noderef;	540	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
569		541
570	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	542	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
571		543
572	unless (ref $cb) {	544	unless (ref $cb) {
573	if (@_) {	545	if (@_) {
…		…
593	is killed, the references will be freed.	565	is killed, the references will be freed.
594		566
595	Optionally returns a guard that will stop the monitoring.	567	Optionally returns a guard that will stop the monitoring.
596		568
597	This function is useful when you create e.g. timers or other watchers and	569	This function is useful when you create e.g. timers or other watchers and
598	want to free them when the port gets killed:	570	want to free them when the port gets killed (note the use of C<psub>):
599		571
600	$port->rcv (start => sub {	572	$port->rcv (start => sub {
601	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	573	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
602	undef $timer if 0.9 < rand;	574	undef $timer if 0.9 < rand;
603	});	575	});
604	});	576	});
605		577
606	=cut	578	=cut
…		…
615		587
616	=item kil $port[, @reason]	588	=item kil $port[, @reason]
617		589
618	Kill the specified port with the given C<@reason>.	590	Kill the specified port with the given C<@reason>.
619		591
620	If no C<@reason> is specified, then the port is killed "normally" (linked	592	If no C<@reason> is specified, then the port is killed "normally" (ports
621	ports will not be kileld, or even notified).	593	monitoring other ports will not necessarily die because a port dies
		594	"normally").
622		595
623	Otherwise, linked ports get killed with the same reason (second form of	596	Otherwise, linked ports get killed with the same reason (second form of
624	C<mon>, see below).	597	C<mon>, see above).
625		598
626	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	599	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
627	will be reported as reason C<< die => $@ >>.	600	will be reported as reason C<< die => $@ >>.
628		601
629	Transport/communication errors are reported as C<< transport_error =>	602	Transport/communication errors are reported as C<< transport_error =>
…		…
634	=item $port = spawn $node, $initfunc[, @initdata]	607	=item $port = spawn $node, $initfunc[, @initdata]
635		608
636	Creates a port on the node C<$node> (which can also be a port ID, in which	609	Creates a port on the node C<$node> (which can also be a port ID, in which
637	case it's the node where that port resides).	610	case it's the node where that port resides).
638		611
639	The port ID of the newly created port is return immediately, and it is	612	The port ID of the newly created port is returned immediately, and it is
640	permissible to immediately start sending messages or monitor the port.	613	possible to immediately start sending messages or to monitor the port.
641		614
642	After the port has been created, the init function is	615	After the port has been created, the init function is called on the remote
643	called. This function must be a fully-qualified function name	616	node, in the same context as a C<rcv> callback. This function must be a
644	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	617	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
645	program, use C<::name>.	618	specify a function in the main program, use C<::name>.
646		619
647	If the function doesn't exist, then the node tries to C<require>	620	If the function doesn't exist, then the node tries to C<require>
648	the package, then the package above the package and so on (e.g.	621	the package, then the package above the package and so on (e.g.
649	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	622	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
650	exists or it runs out of package names.	623	exists or it runs out of package names.
651		624
652	The init function is then called with the newly-created port as context	625	The init function is then called with the newly-created port as context
653	object (C<$SELF>) and the C<@initdata> values as arguments.	626	object (C<$SELF>) and the C<@initdata> values as arguments.
654		627
655	A common idiom is to pass your own port, monitor the spawned port, and	628	A common idiom is to pass a local port, immediately monitor the spawned
656	in the init function, monitor the original port. This two-way monitoring	629	port, and in the remote init function, immediately monitor the passed
657	ensures that both ports get cleaned up when there is a problem.	630	local port. This two-way monitoring ensures that both ports get cleaned up
		631	when there is a problem.
658		632
659	Example: spawn a chat server port on C<$othernode>.	633	Example: spawn a chat server port on C<$othernode>.
660		634
661	# this node, executed from within a port context:	635	# this node, executed from within a port context:
662	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	636	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
685	};	659	};
686	_self_die if $@;	660	_self_die if $@;
687	}	661	}
688		662
689	sub spawn(@) {	663	sub spawn(@) {
690	my ($noderef, undef) = split /#/, shift, 2;	664	my ($nodeid, undef) = split /#/, shift, 2;
691		665
692	my $id = "$RUNIQ." . $ID++;	666	my $id = "$RUNIQ." . $ID++;
693		667
694	$_[0] =~ /::/	668	$_[0] =~ /::/
695	or Carp::croak "spawn init function must be a fully-qualified name, caught";	669	or Carp::croak "spawn init function must be a fully-qualified name, caught";
696		670
697	($NODE{$noderef} \|\| add_node $noderef)	671	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
698	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
699		672
700	"$noderef#$id"	673	"$nodeid#$id"
701	}	674	}
702		675
703	=back	676	=item after $timeout, @msg
704		677
705	=head1 NODE MESSAGES	678	=item after $timeout, $callback
706		679
707	Nodes understand the following messages sent to them. Many of them take	680	Either sends the given message, or call the given callback, after the
708	arguments called C<@reply>, which will simply be used to compose a reply	681	specified number of seconds.
709	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
710	the remaining arguments are simply the message data.
711		682
712	While other messages exist, they are not public and subject to change.	683	This is simply a utility function that comes in handy at times - the
		684	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		685	so it may go away in the future.
713		686
714	=over 4
715
716	=cut	687	=cut
717		688
718	=item lookup => $name, @reply	689	sub after($@) {
		690	my ($timeout, @action) = @_;
719		691
720	Replies with the port ID of the specified well-known port, or C<undef>.	692	my $t; $t = AE::timer $timeout, 0, sub {
721		693	undef $t;
722	=item devnull => ...	694	ref $action[0]
723		695	? $action[0]()
724	Generic data sink/CPU heat conversion.	696	: snd @action;
725		697	};
726	=item relay => $port, @msg	698	}
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		699
749	=back	700	=back
750		701
751	=head1 AnyEvent::MP vs. Distributed Erlang	702	=head1 AnyEvent::MP vs. Distributed Erlang
752		703
…		…
762		713
763	Despite the similarities, there are also some important differences:	714	Despite the similarities, there are also some important differences:
764		715
765	=over 4	716	=over 4
766		717
767	=item * Node references contain the recipe on how to contact them.	718	=item * Node IDs are arbitrary strings in AEMP.
768		719
769	Erlang relies on special naming and DNS to work everywhere in the	720	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	721	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
771	convenience functionality.	722	configuration or DNS), but will otherwise discover other odes itself.
772		723
773	This means that AEMP requires a less tightly controlled environment at the	724	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
774	cost of longer node references and a slightly higher management overhead.	725	uses "local ports are like remote ports".
		726
		727	The failure modes for local ports are quite different (runtime errors
		728	only) then for remote ports - when a local port dies, you I<know> it dies,
		729	when a connection to another node dies, you know nothing about the other
		730	port.
		731
		732	Erlang pretends remote ports are as reliable as local ports, even when
		733	they are not.
		734
		735	AEMP encourages a "treat remote ports differently" philosophy, with local
		736	ports being the special case/exception, where transport errors cannot
		737	occur.
775		738
776	=item * Erlang uses processes and a mailbox, AEMP does not queue.	739	=item * Erlang uses processes and a mailbox, AEMP does not queue.
777		740
778	Erlang uses processes that selctively receive messages, and therefore	741	Erlang uses processes that selectively receive messages, and therefore
779	needs a queue. AEMP is event based, queuing messages would serve no useful	742	needs a queue. AEMP is event based, queuing messages would serve no
780	purpose.	743	useful purpose. For the same reason the pattern-matching abilities of
		744	AnyEvent::MP are more limited, as there is little need to be able to
		745	filter messages without dequeuing them.
781		746
782	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	747	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
783		748
784	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	749	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
785		750
786	Sending messages in Erlang is synchronous and blocks the process. AEMP	751	Sending messages in Erlang is synchronous and blocks the process (and
787	sends are immediate, connection establishment is handled in the	752	so does not need a queue that can overflow). AEMP sends are immediate,
788	background.	753	connection establishment is handled in the background.
789		754
790	=item * Erlang can silently lose messages, AEMP cannot.	755	=item * Erlang suffers from silent message loss, AEMP does not.
791		756
792	Erlang makes few guarantees on messages delivery - messages can get lost	757	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,	758	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).	759	and c, and the other side only receives messages a and c).
795		760
796	AEMP guarantees correct ordering, and the guarantee that there are no	761	AEMP guarantees correct ordering, and the guarantee that after one message
797	holes in the message sequence.	762	is lost, all following ones sent to the same port are lost as well, until
798		763	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	764	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		765
810	=item * Erlang can send messages to the wrong port, AEMP does not.	766	=item * Erlang can send messages to the wrong port, AEMP does not.
811		767
812	In Erlang it is quite possible that a node that restarts reuses a process	768	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	769	known to other nodes for a completely different process, causing messages
814	messages destined for that process to end up in an unrelated process.	770	destined for that process to end up in an unrelated process.
815		771
816	AEMP never reuses port IDs, so old messages or old port IDs floating	772	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.	773	around in the network will not be sent to an unrelated port.
818		774
819	=item * Erlang uses unprotected connections, AEMP uses secure	775	=item * Erlang uses unprotected connections, AEMP uses secure
820	authentication and can use TLS.	776	authentication and can use TLS.
821		777
822	AEMP can use a proven protocol - SSL/TLS - to protect connections and	778	AEMP can use a proven protocol - TLS - to protect connections and
823	securely authenticate nodes.	779	securely authenticate nodes.
824		780
825	=item * The AEMP protocol is optimised for both text-based and binary	781	=item * The AEMP protocol is optimised for both text-based and binary
826	communications.	782	communications.
827		783
828	The AEMP protocol, unlike the Erlang protocol, supports both	784	The AEMP protocol, unlike the Erlang protocol, supports both programming
829	language-independent text-only protocols (good for debugging) and binary,	785	language independent text-only protocols (good for debugging) and binary,
830	language-specific serialisers (e.g. Storable).	786	language-specific serialisers (e.g. Storable). By default, unless TLS is
		787	used, the protocol is actually completely text-based.
831		788
832	It has also been carefully designed to be implementable in other languages	789	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	790	with a minimum of work while gracefully degrading functionality to make the
834	protocol simple.	791	protocol simple.
835		792
836	=item * AEMP has more flexible monitoring options than Erlang.	793	=item * AEMP has more flexible monitoring options than Erlang.
837		794
838	In Erlang, you can chose to receive I<all> exit signals as messages	795	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	798	Erlang, as one can choose between automatic kill, exit message or callback
842	on a per-process basis.	799	on a per-process basis.
843		800
844	=item * Erlang tries to hide remote/local connections, AEMP does not.	801	=item * Erlang tries to hide remote/local connections, AEMP does not.
845		802
846	Monitoring in Erlang is not an indicator of process death/crashes,	803	Monitoring in Erlang is not an indicator of process death/crashes, in the
847	as linking is (except linking is unreliable in Erlang).	804	same way as linking is (except linking is unreliable in Erlang).
848		805
849	In AEMP, you don't "look up" registered port names or send to named ports	806	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	807	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	808	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	809	remote port. Since both monitors are local to the node, they are much more
853	more reliable.	810	reliable (no need for C<spawn_link>).
854		811
855	This also saves round-trips and avoids sending messages to the wrong port	812	This also saves round-trips and avoids sending messages to the wrong port
856	(hard to do in Erlang).	813	(hard to do in Erlang).
857		814
858	=back	815	=back
859		816
		817	=head1 RATIONALE
		818
		819	=over 4
		820
		821	=item Why strings for port and node IDs, why not objects?
		822
		823	We considered "objects", but found that the actual number of methods
		824	that can be called are quite low. Since port and node IDs travel over
		825	the network frequently, the serialising/deserialising would add lots of
		826	overhead, as well as having to keep a proxy object everywhere.
		827
		828	Strings can easily be printed, easily serialised etc. and need no special
		829	procedures to be "valid".
		830
		831	And as a result, a miniport consists of a single closure stored in a
		832	global hash - it can't become much cheaper.
		833
		834	=item Why favour JSON, why not a real serialising format such as Storable?
		835
		836	In fact, any AnyEvent::MP node will happily accept Storable as framing
		837	format, but currently there is no way to make a node use Storable by
		838	default (although all nodes will accept it).
		839
		840	The default framing protocol is JSON because a) JSON::XS is many times
		841	faster for small messages and b) most importantly, after years of
		842	experience we found that object serialisation is causing more problems
		843	than it solves: Just like function calls, objects simply do not travel
		844	easily over the network, mostly because they will always be a copy, so you
		845	always have to re-think your design.
		846
		847	Keeping your messages simple, concentrating on data structures rather than
		848	objects, will keep your messages clean, tidy and efficient.
		849
		850	=back
		851
860	=head1 SEE ALSO	852	=head1 SEE ALSO
		853
		854	L<AnyEvent::MP::Intro> - a gentle introduction.
		855
		856	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		857
		858	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		859	your applications.
861		860
862	L<AnyEvent>.	861	L<AnyEvent>.
863		862
864	=head1 AUTHOR	863	=head1 AUTHOR
865		864

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.45 by root, Thu Aug 13 01:16:24 2009 UTC vs. Revision 1.79 by root, Fri Sep 4 21:52:09 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.45 by root, Thu Aug 13 01:16:24 2009 UTC vs.
Revision 1.79 by root, Fri Sep 4 21:52:09 2009 UTC