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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.36 by root, Thu Aug 6 10:46:48 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
		12	$SELF # receiving/own port id in rcv callbacks
		13
		14	# initialise the node so it can send/receive messages
		15	configure;
		16
		17	# ports are message destinations
		18
		19	# sending messages
13	snd $port, type => data...;	20	snd $port, type => data...;
		21	snd $port, @msg;
		22	snd @msg_with_first_element_being_a_port;
14		23
15	$SELF # receiving/own port id in rcv callbacks	24	# creating/using ports, the simple way
		25	my $simple_port = port { my @msg = @_ };
16		26
17	rcv $port, smartmatch => $cb->($port, @msg);	27	# creating/using ports, tagged message matching
18		28	my $port = port;
19	# examples:
20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
21	rcv $port1, pong => sub { warn "pong received\n" };	30	rcv $port, pong => sub { warn "pong received\n" };
22	snd $port2, ping => $port1;
23		31
24	# more, smarter, matches (_any_ is exported by this module)	32	# create a port on another node
25	rcv $port, [child_died => $pid] => sub { ...	33	my $port = spawn $node, $initfunc, @initdata;
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
27
28	# linking two ports, so they both crash together
29	lnk $port1, $port2;
30		34
31	# monitoring	35	# monitoring
32	mon $port, $cb->(@msg) # callback is invoked on death	36	mon $port, $cb->(@msg) # callback is invoked on death
33	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
34	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
35		39
		40	=head1 CURRENT STATUS
		41
		42	bin/aemp - stable.
		43	AnyEvent::MP - stable API, should work.
		44	AnyEvent::MP::Intro - explains most concepts.
		45	AnyEvent::MP::Kernel - mostly stable.
		46	AnyEvent::MP::Global - stable but incomplete, protocol not yet final.
		47
		48	stay tuned.
		49
36	=head1 DESCRIPTION	50	=head1 DESCRIPTION
37		51
38	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
39		53
40	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
41	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
42		56
43	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>
44	manual page.	58	manual page and the examples under F<eg/>.
45
46	At the moment, this module family is severly broken and underdocumented,
47	so do not use. This was uploaded mainly to reserve the CPAN namespace -
48	stay tuned! The basic API should be finished, however.
49		59
50	=head1 CONCEPTS	60	=head1 CONCEPTS
51		61
52	=over 4	62	=over 4
53		63
54	=item port	64	=item port
55		65
56	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).
57		68
58	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
59	messages. All C<rcv> handlers will receive messages they match, messages	70	some messages. Messages send to ports will not be queued, regardless of
60	will not be queued.	71	anything was listening for them or not.
61		72
62	=item port id - C<noderef#portname>	73	=item port ID - C<nodeid#portname>
63		74
64	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
65	separator, and a port name (a printable string of unspecified format). An	76	separator, and a port name (a printable string of unspecified format).
66	exception is the the node port, whose ID is identical to its node
67	reference.
68		77
69	=item node	78	=item node
70		79
71	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,
72	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
73	create new ports, among other things.	82	ports.
74		83
75	Nodes are either private (single-process only), slaves (connected to a	84	Nodes are either public (have one or more listening ports) or private
76	master node only) or public nodes (connectable from unrelated nodes).	85	(no listening ports). Private nodes cannot talk to other private nodes
		86	currently.
77		87
78	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	88	=item node ID - C<[a-za-Z0-9_\-.:]+>
79		89
80	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
81	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
82	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.
83		94
84	This recipe is simply a comma-separated list of C<address:port> pairs (for	95	=item binds - C<ip:port>
85	TCP/IP, other protocols might look different).
86		96
87	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
88	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.
89		101
90	Before using an unresolved node reference in a message you first have to	102	=item seeds - C<host:port>
91	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.
92		116
93	=back	117	=back
94		118
95	=head1 VARIABLES/FUNCTIONS	119	=head1 VARIABLES/FUNCTIONS
96		120
…		…
98		122
99	=cut	123	=cut
100		124
101	package AnyEvent::MP;	125	package AnyEvent::MP;
102		126
103	use AnyEvent::MP::Base;	127	use AnyEvent::MP::Kernel;
104		128
105	use common::sense;	129	use common::sense;
106		130
107	use Carp ();	131	use Carp ();
108		132
109	use AE ();	133	use AE ();
110		134
111	use base "Exporter";	135	use base "Exporter";
112		136
113	our $VERSION = '0.1';	137	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		138
114	our @EXPORT = qw(	139	our @EXPORT = qw(
115	NODE $NODE *SELF node_of _any_	140	NODE $NODE *SELF node_of after
116	resolve_node initialise_node	141	configure
117	snd rcv mon kil reg psub	142	snd rcv mon mon_guard kil reg psub spawn
118	port	143	port
119	);	144	);
120		145
121	our $SELF;	146	our $SELF;
122		147
…		…
126	kil $SELF, die => $msg;	151	kil $SELF, die => $msg;
127	}	152	}
128		153
129	=item $thisnode = NODE / $NODE	154	=item $thisnode = NODE / $NODE
130		155
131	The C<NODE> function returns, and the C<$NODE> variable contains	156	The C<NODE> function returns, and the C<$NODE> variable contains, the node
132	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
133	to C<become_public> or C<become_slave>, after which all local port	158	a call to C<configure>.
134	identifiers become invalid.
135		159
136	=item $noderef = node_of $port	160	=item $nodeid = node_of $port
137		161
138	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.
139		163
140	=item initialise_node $noderef, $seednode, $seednode...	164	=item configure $profile, key => value...
141		165
142	=item initialise_node "slave/", $master, $master...	166	=item configure key => value...
143		167
144	Before a node can talk to other nodes on the network it has to initialise	168	Before a node can talk to other nodes on the network (i.e. enter
145	itself - the minimum a node needs to know is it's own name, and optionally	169	"distributed mode") it has to configure itself - the minimum a node needs
146	it should know the noderefs of some other nodes in the network.	170	to know is its own name, and optionally it should know the addresses of
		171	some other nodes in the network to discover other nodes.
147		172
148	This function initialises a node - it must be called exactly once (or	173	This function configures a node - it must be called exactly once (or
149	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
150		175
151	All arguments are noderefs, which can be either resolved or unresolved.
152
153	There are two types of networked nodes, public nodes and slave nodes:
154
155	=over 4	176	=over 4
156		177
157	=item public nodes	178	=item step 1, gathering configuration from profiles
158		179
159	For public nodes, C<$noderef> must either be a (possibly unresolved)	180	The function first looks up a profile in the aemp configuration (see the
160	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
161	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.
162		184
163	Afterwards, the node will bind itself on all endpoints and try to connect	185	The profile data is then gathered as follows:
164	to all additional C<$seednodes> that are specified. Seednodes are optional
165	and can be used to quickly bootstrap the node into an existing network.
166		186
167	=item slave nodes	187	First, all remaining key => value pairs (all of which are conveniently
		188	undocumented at the moment) will be interpreted as configuration
		189	data. Then they will be overwritten by any values specified in the global
		190	default configuration (see the F<aemp> utility), then the chain of
		191	profiles chosen by the profile name (and any C<parent> attributes).
168		192
169	When the C<$noderef> is the special string C<slave/>, then the node will	193	That means that the values specified in the profile have highest priority
170	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,
171	route most of their traffic to the master node that they attach to.	195	and can only be used to specify defaults.
172		196
173	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
174	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
175	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.
176		218
177	=back	219	=back
178		220
179	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.
180	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.
181	server.
182		223
183	Example: become a public node listening on the default node.	224	configure
184		225
185	initialise_node;	226	Example: become an anonymous node. This form is often used for commandline
		227	clients.
186		228
187	Example: become a public node, and try to contact some well-known master	229	configure nodeid => "anon/";
188	servers to become part of the network.
189		230
190	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).
191		234
192	Example: become a public node listening on port C<4041>.	235	# use the aemp commandline utility
		236	# aemp profile seed nodeid anon/ binds '*:4040'
193		237
194	initialise_node 4041;	238	# then use it
		239	configure profile => "seed";
195		240
196	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
197		243
198	initialise_node "locahost:4044";	244	# or provide a nicer-to-remember nodeid
199		245	# aemp run profile seed nodeid "$(hostname)"
200	Example: become a slave node to any of the specified master servers.
201
202	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
203
204	=item $cv = resolve_node $noderef
205
206	Takes an unresolved node reference that may contain hostnames and
207	abbreviated IDs, resolves all of them and returns a resolved node
208	reference.
209
210	In addition to C<address:port> pairs allowed in resolved noderefs, the
211	following forms are supported:
212
213	=over 4
214
215	=item the empty string
216
217	An empty-string component gets resolved as if the default port (4040) was
218	specified.
219
220	=item naked port numbers (e.g. C<1234>)
221
222	These are resolved by prepending the local nodename and a colon, to be
223	further resolved.
224
225	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
226
227	These are resolved by using AnyEvent::DNS to resolve them, optionally
228	looking up SRV records for the C<aemp=4040> port, if no port was
229	specified.
230
231	=back
232		246
233	=item $SELF	247	=item $SELF
234		248
235	Contains the current port id while executing C<rcv> callbacks or C<psub>	249	Contains the current port id while executing C<rcv> callbacks or C<psub>
236	blocks.	250	blocks.
237		251
238	=item SELF, %SELF, @SELF...	252	=item *SELF, SELF, %SELF, @SELF...
239		253
240	Due to some quirks in how perl exports variables, it is impossible to	254	Due to some quirks in how perl exports variables, it is impossible to
241	just export C<$SELF>, all the symbols called C<SELF> are exported by this	255	just export C<$SELF>, all the symbols named C<SELF> are exported by this
242	module, but only C<$SELF> is currently used.	256	module, but only C<$SELF> is currently used.
243		257
244	=item snd $port, type => @data	258	=item snd $port, type => @data
245		259
246	=item snd $port, @msg	260	=item snd $port, @msg
247		261
248	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
249	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.
250	stringifies a sa port ID (such as a port object :).
251		264
252	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
253	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
254	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.
255		269
256	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
257	function: modifying any argument is not allowed and can cause many	271	function: modifying any argument (or values referenced by them) is
258	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.
259		276
260	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
261	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
262	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
263	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
264	node, anything can be passed.	281	node, anything can be passed. Best rely only on the common denominator of
		282	these.
265		283
266	=item $local_port = port	284	=item $local_port = port
267		285
268	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
269	matching port ("full port") or a single-callback port ("miniport"),	287	no callbacks set and will throw an error when it receives messages.
270	depending on how C<rcv> callbacks are bound to the object.
271		288
272	=item $port = port { my @msg = @_; $finished }	289	=item $local_port = port { my @msg = @_ }
273		290
274	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
275	matching behind it, and returns its ID. Semantically the same as creating
276	a port and calling C<rcv $port, $callback> on it.	292	creating a port and calling C<rcv $port, $callback> on it.
277		293
278	The block will be called for every message received on the port. When the	294	The block will be called for every message received on the port, with the
279	callback returns a true value its job is considered "done" and the port	295	global variable C<$SELF> set to the port ID. Runtime errors will cause the
280	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.
281		298
282	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:
283	be passed to the callback.
284		300
285	If you need the local port id in the callback, this works nicely:	301	my $port = port {
286		302	my @msg = @_;
287	my $port; $port = port {	303	...
288	snd $otherport, reply => $port;	304	kil $SELF;
289	};	305	};
290		306
291	=cut	307	=cut
292		308
293	sub rcv($@);	309	sub rcv($@);
		310
		311	sub _kilme {
		312	die "received message on port without callback";
		313	}
294		314
295	sub port(;&) {	315	sub port(;&) {
296	my $id = "$UNIQ." . $ID++;	316	my $id = "$UNIQ." . $ID++;
297	my $port = "$NODE#$id";	317	my $port = "$NODE#$id";
298		318
299	if (@_) {	319	rcv $port, shift \|\| \&_kilme;
300	rcv $port, shift;
301	} else {
302	$PORT{$id} = sub { }; # nop
303	}
304		320
305	$port	321	$port
306	}	322	}
307		323
308	=item reg $port, $name
309
310	=item reg $name
311
312	Registers the given port (or C<$SELF><<< if missing) under the name
313	C<$name>. If the name already exists it is replaced.
314
315	A port can only be registered under one well known name.
316
317	A port automatically becomes unregistered when it is killed.
318
319	=cut
320
321	sub reg(@) {
322	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
323
324	$REG{$_[0]} = $port;
325	}
326
327	=item rcv $port, $callback->(@msg)	324	=item rcv $local_port, $callback->(@msg)
328		325
329	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
330	one if required).	327	remove the default callback: use C<sub { }> to disable it, or better
331		328	C<kil> the port when it is no longer needed.
332	=item rcv $port, tagstring => $callback->(@msg), ...
333
334	=item rcv $port, $smartmatch => $callback->(@msg), ...
335
336	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
337
338	Register callbacks to be called on matching messages on the given full
339	port (after converting it to one if required) and return the port.
340
341	The callback has to return a true value when its work is done, after
342	which is will be removed, or a false value in which case it will stay
343	registered.
344		329
345	The global C<$SELF> (exported by this module) contains C<$port> while	330	The global C<$SELF> (exported by this module) contains C<$port> while
346	executing the callback.	331	executing the callback. Runtime errors during callback execution will
		332	result in the port being C<kil>ed.
347		333
348	Runtime errors wdurign callback execution will result in the port being	334	The default callback received all messages not matched by a more specific
349	C<kil>ed.	335	C<tag> match.
350		336
351	If the match is an array reference, then it will be matched against the	337	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
352	first elements of the message, otherwise only the first element is being
353	matched.
354		338
355	Any element in the match that is specified as C<_any_> (a function	339	Register (or replace) callbacks to be called on messages starting with the
356	exported by this module) matches any single element of the message.	340	given tag on the given port (and return the port), or unregister it (when
		341	C<$callback> is C<$undef> or missing). There can only be one callback
		342	registered for each tag.
357		343
358	While not required, it is highly recommended that the first matching	344	The original message will be passed to the callback, after the first
359	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
360	also the most efficient match (by far).	346	environment as the default callback (see above).
361		347
362	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.
363		349
364	my $port = rcv port,	350	my $port = rcv port,
365	msg1 => sub { ...; 0 },	351	msg1 => sub { ... },
366	msg2 => sub { ...; 0 },	352	msg2 => sub { ... },
367	;	353	;
368		354
369	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
370	in one go:	356	in one go:
371		357
372	snd $otherport, reply =>	358	snd $otherport, reply =>
373	rcv port,	359	rcv port,
374	msg1 => sub { ...; 0 },	360	msg1 => sub { ... },
375	...	361	...
376	;	362	;
377		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, $otherport;
		371	};
		372
378	=cut	373	=cut
379		374
380	sub rcv($@) {	375	sub rcv($@) {
381	my $port = shift;	376	my $port = shift;
382	my ($noderef, $portid) = split /#/, $port, 2;	377	my ($nodeid, $portid) = split /#/, $port, 2;
383		378
384	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	379	$NODE{$nodeid} == $NODE{""}
385	or Carp::croak "$port: rcv can only be called on local ports, caught";	380	or Carp::croak "$port: rcv can only be called on local ports, caught";
386		381
387	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 {
388	my $cb = shift;	390	my $cb = shift;
389	delete $PORT_DATA{$portid};
390	$PORT{$portid} = sub {	391	$PORT{$portid} = sub {
391	local $SELF = $port;	392	local $SELF = $port;
392	eval {	393	eval { &$cb }; _self_die if $@;
393	&$cb	394	};
394	and kil $port;
395	};	395	}
396	_self_die if $@;	396	} elsif (defined $_[0]) {
397	};
398	} else {
399	my $self = $PORT_DATA{$portid} \|\|= do {	397	my $self = $PORT_DATA{$portid} \|\|= do {
400	my $self = bless {	398	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
401	id => $port,
402	}, "AnyEvent::MP::Port";
403		399
404	$PORT{$portid} = sub {	400	$PORT{$portid} = sub {
405	local $SELF = $port;	401	local $SELF = $port;
406		402
407	eval {
408	for (@{ $self->{rc0}{$_[0]} }) {	403	if (my $cb = $self->[1]{$_[0]}) {
409	$_ && &{$_->[0]}	404	shift;
410	&& undef $_;	405	eval { &$cb }; _self_die if $@;
411	}	406	} else {
412
413	for (@{ $self->{rcv}{$_[0]} }) {
414	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
415	&& &{$_->[0]}	407	&{ $self->[0] };
416	&& undef $_;
417	}
418
419	for (@{ $self->{any} }) {
420	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
421	&& &{$_->[0]}
422	&& undef $_;
423	}	408	}
424	};	409	};
425	_self_die if $@;	410
		411	$self
426	};	412	};
427		413
428	$self
429	};
430
431	"AnyEvent::MP::Port" eq ref $self	414	"AnyEvent::MP::Port" eq ref $self
432	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	415	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
433		416
434	while (@_) {
435	my ($match, $cb) = splice @_, 0, 2;	417	my ($tag, $cb) = splice @_, 0, 2;
436		418
437	if (!ref $match) {	419	if (defined $cb) {
438	push @{ $self->{rc0}{$match} }, [$cb];	420	$self->[1]{$tag} = $cb;
439	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
440	my ($type, @match) = @$match;
441	@match
442	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
443	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
444	} else {	421	} else {
445	push @{ $self->{any} }, [$cb, $match];	422	delete $self->[1]{$tag};
446	}	423	}
447	}	424	}
448	}	425	}
449		426
450	$port	427	$port
…		…
486	$res	463	$res
487	}	464	}
488	}	465	}
489	}	466	}
490		467
491	=item $guard = mon $port, $cb->(@reason)	468	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
492		469
493	=item $guard = mon $port, $rcvport	470	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
494		471
495	=item $guard = mon $port	472	=item $guard = mon $port # kill $SELF when $port dies
496		473
497	=item $guard = mon $port, $rcvport, @msg	474	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
498		475
499	Monitor the given port and do something when the port is killed, and	476	Monitor the given port and do something when the port is killed or
500	optionally return a guard that can be used to stop monitoring again.	477	messages to it were lost, and optionally return a guard that can be used
		478	to stop monitoring again.
501		479
502	In the first form (callback), the callback is simply called with any	480	In the first form (callback), the callback is simply called with any
503	number of C<@reason> elements (no @reason means that the port was deleted	481	number of C<@reason> elements (no @reason means that the port was deleted
504	"normally"). Note also that I<< the callback B<must> never die >>, so use	482	"normally"). Note also that I<< the callback B<must> never die >>, so use
505	C<eval> if unsure.	483	C<eval> if unsure.
506		484
507	In the second form (another port given), the other port (C<$rcvport)	485	In the second form (another port given), the other port (C<$rcvport>)
508	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	486	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
509	"normal" kils nothing happens, while under all other conditions, the other	487	"normal" kils nothing happens, while under all other conditions, the other
510	port is killed with the same reason.	488	port is killed with the same reason.
511		489
512	The third form (kill self) is the same as the second form, except that	490	The third form (kill self) is the same as the second form, except that
513	C<$rvport> defaults to C<$SELF>.	491	C<$rvport> defaults to C<$SELF>.
514		492
515	In the last form (message), a message of the form C<@msg, @reason> will be	493	In the last form (message), a message of the form C<@msg, @reason> will be
516	C<snd>.	494	C<snd>.
517		495
		496	Monitoring-actions are one-shot: once messages are lost (and a monitoring
		497	alert was raised), they are removed and will not trigger again.
		498
		499	As a rule of thumb, monitoring requests should always monitor a port from
		500	a local port (or callback). The reason is that kill messages might get
		501	lost, just like any other message. Another less obvious reason is that
		502	even monitoring requests can get lost (for example, when the connection
		503	to the other node goes down permanently). When monitoring a port locally
		504	these problems do not exist.
		505
		506	C<mon> effectively guarantees that, in the absence of hardware failures,
		507	after starting the monitor, either all messages sent to the port will
		508	arrive, or the monitoring action will be invoked after possible message
		509	loss has been detected. No messages will be lost "in between" (after
		510	the first lost message no further messages will be received by the
		511	port). After the monitoring action was invoked, further messages might get
		512	delivered again.
		513
		514	Inter-host-connection timeouts and monitoring depend on the transport
		515	used. The only transport currently implemented is TCP, and AnyEvent::MP
		516	relies on TCP to detect node-downs (this can take 10-15 minutes on a
		517	non-idle connection, and usually around two hours for idle conenctions).
		518
		519	This means that monitoring is good for program errors and cleaning up
		520	stuff eventually, but they are no replacement for a timeout when you need
		521	to ensure some maximum latency.
		522
518	Example: call a given callback when C<$port> is killed.	523	Example: call a given callback when C<$port> is killed.
519		524
520	mon $port, sub { warn "port died because of <@_>\n" };	525	mon $port, sub { warn "port died because of <@_>\n" };
521		526
522	Example: kill ourselves when C<$port> is killed abnormally.	527	Example: kill ourselves when C<$port> is killed abnormally.
…		…
528	mon $port, $self => "restart";	533	mon $port, $self => "restart";
529		534
530	=cut	535	=cut
531		536
532	sub mon {	537	sub mon {
533	my ($noderef, $port) = split /#/, shift, 2;	538	my ($nodeid, $port) = split /#/, shift, 2;
534		539
535	my $node = $NODE{$noderef} \|\| add_node $noderef;	540	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
536		541
537	my $cb = @_ ? $_[0] : $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,';
538		543
539	unless (ref $cb) {	544	unless (ref $cb) {
540	if (@_) {	545	if (@_) {
541	# send a kill info message	546	# send a kill info message
542	my (@msg) = @_;	547	my (@msg) = ($cb, @_);
543	$cb = sub { snd @msg, @_ };	548	$cb = sub { snd @msg, @_ };
544	} else {	549	} else {
545	# simply kill other port	550	# simply kill other port
546	my $port = $cb;	551	my $port = $cb;
547	$cb = sub { kil $port, @_ if @_ };	552	$cb = sub { kil $port, @_ if @_ };
…		…
560	is killed, the references will be freed.	565	is killed, the references will be freed.
561		566
562	Optionally returns a guard that will stop the monitoring.	567	Optionally returns a guard that will stop the monitoring.
563		568
564	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
565	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>):
566		571
567	$port->rcv (start => sub {	572	$port->rcv (start => sub {
568	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	573	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
569	undef $timer if 0.9 < rand;	574	undef $timer if 0.9 < rand;
570	});	575	});
571	});	576	});
572		577
573	=cut	578	=cut
…		…
578	#TODO: mon-less form?	583	#TODO: mon-less form?
579		584
580	mon $port, sub { 0 && @refs }	585	mon $port, sub { 0 && @refs }
581	}	586	}
582		587
583	=item lnk $port1, $port2
584
585	=item lnk $otherport
586
587	Link two ports. This is simply a shorthand for:
588
589	mon $port1, $port2;
590	mon $port2, $port1;
591
592	It means that if either one is killed abnormally, the other one gets
593	killed as well.
594
595	The one-argument form assumes that one port is C<$SELF>.
596
597	=cut
598
599	sub lnk {
600	my $port1 = shift;
601	my $port2 = @_ ? shift : $SELF \|\| Carp::croak 'lnk: called with one argument only, but $SELF not set,';
602
603	mon $port1, $port2;
604	mon $port2, $port1;
605	}
606
607	=item kil $port[, @reason]	588	=item kil $port[, @reason]
608		589
609	Kill the specified port with the given C<@reason>.	590	Kill the specified port with the given C<@reason>.
610		591
611	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
612	ports will not be kileld, or even notified).	593	monitoring other ports will not necessarily die because a port dies
		594	"normally").
613		595
614	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
615	C<mon>, see below).	597	C<mon>, see above).
616		598
617	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
618	will be reported as reason C<< die => $@ >>.	600	will be reported as reason C<< die => $@ >>.
619		601
620	Transport/communication errors are reported as C<< transport_error =>	602	Transport/communication errors are reported as C<< transport_error =>
621	$message >>.	603	$message >>.
622		604
623	=back
624
625	=head1 NODE MESSAGES
626
627	Nodes understand the following messages sent to them. Many of them take
628	arguments called C<@reply>, which will simply be used to compose a reply
629	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
630	the remaining arguments are simply the message data.
631
632	While other messages exist, they are not public and subject to change.
633
634	=over 4
635
636	=cut	605	=cut
637		606
638	=item lookup => $name, @reply	607	=item $port = spawn $node, $initfunc[, @initdata]
639		608
640	Replies with the port ID of the specified well-known port, or C<undef>.	609	Creates a port on the node C<$node> (which can also be a port ID, in which
		610	case it's the node where that port resides).
641		611
642	=item devnull => ...	612	The port ID of the newly created port is returned immediately, and it is
		613	possible to immediately start sending messages or to monitor the port.
643		614
644	Generic data sink/CPU heat conversion.	615	After the port has been created, the init function is called on the remote
		616	node, in the same context as a C<rcv> callback. This function must be a
		617	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		618	specify a function in the main program, use C<::name>.
645		619
646	=item relay => $port, @msg	620	If the function doesn't exist, then the node tries to C<require>
		621	the package, then the package above the package and so on (e.g.
		622	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		623	exists or it runs out of package names.
647		624
648	Simply forwards the message to the given port.	625	The init function is then called with the newly-created port as context
		626	object (C<$SELF>) and the C<@initdata> values as arguments.
649		627
650	=item eval => $string[ @reply]	628	A common idiom is to pass a local port, immediately monitor the spawned
		629	port, and in the remote init function, immediately monitor the passed
		630	local port. This two-way monitoring ensures that both ports get cleaned up
		631	when there is a problem.
651		632
652	Evaluates the given string. If C<@reply> is given, then a message of the	633	Example: spawn a chat server port on C<$othernode>.
653	form C<@reply, $@, @evalres> is sent.
654		634
655	Example: crash another node.	635	# this node, executed from within a port context:
		636	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		637	mon $server;
656		638
657	snd $othernode, eval => "exit";	639	# init function on C<$othernode>
		640	sub connect {
		641	my ($srcport) = @_;
658		642
659	=item time => @reply	643	mon $srcport;
660		644
661	Replies the the current node time to C<@reply>.	645	rcv $SELF, sub {
		646	...
		647	};
		648	}
662		649
663	Example: tell the current node to send the current time to C<$myport> in a	650	=cut
664	C<timereply> message.
665		651
666	snd $NODE, time => $myport, timereply => 1, 2;	652	sub _spawn {
667	# => snd $myport, timereply => 1, 2, <time>	653	my $port = shift;
		654	my $init = shift;
		655
		656	local $SELF = "$NODE#$port";
		657	eval {
		658	&{ load_func $init }
		659	};
		660	_self_die if $@;
		661	}
		662
		663	sub spawn(@) {
		664	my ($nodeid, undef) = split /#/, shift, 2;
		665
		666	my $id = "$RUNIQ." . $ID++;
		667
		668	$_[0] =~ /::/
		669	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		670
		671	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
		672
		673	"$nodeid#$id"
		674	}
		675
		676	=item after $timeout, @msg
		677
		678	=item after $timeout, $callback
		679
		680	Either sends the given message, or call the given callback, after the
		681	specified number of seconds.
		682
		683	This is simply a utility function that comes in handy at times - the
		684	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		685	so it may go away in the future.
		686
		687	=cut
		688
		689	sub after($@) {
		690	my ($timeout, @action) = @_;
		691
		692	my $t; $t = AE::timer $timeout, 0, sub {
		693	undef $t;
		694	ref $action[0]
		695	? $action[0]()
		696	: snd @action;
		697	};
		698	}
668		699
669	=back	700	=back
670		701
671	=head1 AnyEvent::MP vs. Distributed Erlang	702	=head1 AnyEvent::MP vs. Distributed Erlang
672		703
…		…
682		713
683	Despite the similarities, there are also some important differences:	714	Despite the similarities, there are also some important differences:
684		715
685	=over 4	716	=over 4
686		717
687	=item * Node references contain the recipe on how to contact them.	718	=item * Node IDs are arbitrary strings in AEMP.
688		719
689	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
690	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
691	convenience functionality.	722	configuration or DNS), but will otherwise discover other odes itself.
692		723
693	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
694	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.
695		738
696	=item * Erlang uses processes and a mailbox, AEMP does not queue.	739	=item * Erlang uses processes and a mailbox, AEMP does not queue.
697		740
698	Erlang uses processes that selctively receive messages, and therefore	741	Erlang uses processes that selectively receive messages, and therefore
699	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
700	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.
701		746
702	(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).
703		748
704	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	749	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
705		750
706	Sending messages in Erlang is synchronous and blocks the process. AEMP	751	Sending messages in Erlang is synchronous and blocks the process (and
707	sends are immediate, connection establishment is handled in the	752	so does not need a queue that can overflow). AEMP sends are immediate,
708	background.	753	connection establishment is handled in the background.
709		754
710	=item * Erlang can silently lose messages, AEMP cannot.	755	=item * Erlang suffers from silent message loss, AEMP does not.
711		756
712	Erlang makes few guarantees on messages delivery - messages can get lost	757	Erlang makes few guarantees on messages delivery - messages can get lost
713	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,
714	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).
715		760
716	AEMP guarantees correct ordering, and the guarantee that there are no	761	AEMP guarantees correct ordering, and the guarantee that after one message
717	holes in the message sequence.	762	is lost, all following ones sent to the same port are lost as well, until
718		763	monitoring raises an error, so there are no silent "holes" in the message
719	=item * In Erlang, processes can be declared dead and later be found to be	764	sequence.
720	alive.
721
722	In Erlang it can happen that a monitored process is declared dead and
723	linked processes get killed, but later it turns out that the process is
724	still alive - and can receive messages.
725
726	In AEMP, when port monitoring detects a port as dead, then that port will
727	eventually be killed - it cannot happen that a node detects a port as dead
728	and then later sends messages to it, finding it is still alive.
729		765
730	=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.
731		767
732	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
733	ID known to other nodes for a completely different process, causing	769	known to other nodes for a completely different process, causing messages
734	messages destined for that process to end up in an unrelated process.	770	destined for that process to end up in an unrelated process.
735		771
736	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
737	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.
738		774
739	=item * Erlang uses unprotected connections, AEMP uses secure	775	=item * Erlang uses unprotected connections, AEMP uses secure
740	authentication and can use TLS.	776	authentication and can use TLS.
741		777
742	AEMP can use a proven protocol - SSL/TLS - to protect connections and	778	AEMP can use a proven protocol - TLS - to protect connections and
743	securely authenticate nodes.	779	securely authenticate nodes.
744		780
745	=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
746	communications.	782	communications.
747		783
748	The AEMP protocol, unlike the Erlang protocol, supports both	784	The AEMP protocol, unlike the Erlang protocol, supports both programming
749	language-independent text-only protocols (good for debugging) and binary,	785	language independent text-only protocols (good for debugging) and binary,
750	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.
751		788
752	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
753	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
754	protocol simple.	791	protocol simple.
755		792
756	=item * AEMP has more flexible monitoring options than Erlang.	793	=item * AEMP has more flexible monitoring options than Erlang.
757		794
758	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
759	or I<none>, there is no in-between, so monitoring single processes is	796	or I<none>, there is no in-between, so monitoring single processes is
760	difficult to implement. Monitoring in AEMP is more flexible than in	797	difficult to implement. Monitoring in AEMP is more flexible than in
761	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
762	on a per-process basis.	799	on a per-process basis.
763		800
764	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.	801	=item * Erlang tries to hide remote/local connections, AEMP does not.
765		802
766	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
767	as linking is (except linking is unreliable in Erlang). In AEMP, the	804	same way as linking is (except linking is unreliable in Erlang).
768	semantics of monitoring and linking are identical, linking is simply	805
769	two-way monitoring with automatic kill.	806	In AEMP, you don't "look up" registered port names or send to named ports
		807	that might or might not be persistent. Instead, you normally spawn a port
		808	on the remote node. The init function monitors you, and you monitor the
		809	remote port. Since both monitors are local to the node, they are much more
		810	reliable (no need for C<spawn_link>).
		811
		812	This also saves round-trips and avoids sending messages to the wrong port
		813	(hard to do in Erlang).
770		814
771	=back	815	=back
772		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
773	=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.
774		860
775	L<AnyEvent>.	861	L<AnyEvent>.
776		862
777	=head1 AUTHOR	863	=head1 AUTHOR
778		864

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.36 by root, Thu Aug 6 10:46:48 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 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs.
Revision 1.79 by root, Fri Sep 4 21:52:09 2009 UTC