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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC vs.
Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC

…		…
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
13	$SELF # receiving/own port id in rcv callbacks	13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node;
14		17
15	# ports are message endpoints	18	# ports are message endpoints
16		19
17	# sending messages	20	# sending messages
18	snd $port, type => data...;	21	snd $port, type => data...;
19	snd $port, @msg;	22	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
21		24
22	# miniports	25	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
24		27
25	# full ports	28	# creating/using ports, tagged message matching
26	my $port = port;	29	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		32
31	# remote ports	33	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	34	my $port = spawn $node, $initfunc, @initdata;
33
34	# more, smarter, matches (_any_ is exported by this module)
35	rcv $port, [child_died => $pid] => sub { ...
36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
37		35
38	# monitoring	36	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	37	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	38	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	39	mon $port, $otherport, @msg # send message on death
42		40
		41	=head1 CURRENT STATUS
		42
		43	AnyEvent::MP - stable API, should work
		44	AnyEvent::MP::Intro - outdated
		45	AnyEvent::MP::Kernel - mostly stable
		46	AnyEvent::MP::Global - mostly stable
		47	AnyEvent::MP::Node - mostly stable, but internal anyways
		48	AnyEvent::MP::Transport - mostly stable, but internal anyways
		49
		50	stay tuned.
		51
43	=head1 DESCRIPTION	52	=head1 DESCRIPTION
44		53
45	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
46		55
47	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
48	on the same or other hosts.	57	on the same or other hosts, and you can supervise entities remotely.
49		58
50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
51	manual page.	60	manual page and the examples under F<eg/>.
52		61
53	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is a bit underdocumented.
54	so do not use. This was uploaded mainly to reserve the CPAN namespace -
55	stay tuned! The basic API should be finished, however.
56		63
57	=head1 CONCEPTS	64	=head1 CONCEPTS
58		65
59	=over 4	66	=over 4
60		67
61	=item port	68	=item port
62		69
63	A port is something you can send messages to (with the C<snd> function).	70	A port is something you can send messages to (with the C<snd> function).
64		71
65	Some ports allow you to register C<rcv> handlers that can match specific	72	Ports allow you to register C<rcv> handlers that can match all or just
66	messages. All C<rcv> handlers will receive messages they match, messages	73	some messages. Messages send to ports will not be queued, regardless of
67	will not be queued.	74	anything was listening for them or not.
68		75
69	=item port id - C<noderef#portname>	76	=item port ID - C<nodeid#portname>
70		77
71	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	78	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
72	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format).
73	exception is the the node port, whose ID is identical to its node
74	reference.
75		80
76	=item node	81	=item node
77		82
78	A node is a single process containing at least one port - the node	83	A node is a single process containing at least one port - the node port,
79	port. You can send messages to node ports to find existing ports or to	84	which enables nodes to manage each other remotely, and to create new
80	create new ports, among other things.	85	ports.
81		86
82	Nodes are either private (single-process only), slaves (connected to a	87	Nodes are either public (have one or more listening ports) or private
83	master node only) or public nodes (connectable from unrelated nodes).	88	(no listening ports). Private nodes cannot talk to other private nodes
		89	currently.
84		90
85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	91	=item node ID - C<[a-za-Z0-9_\-.:]+>
86		92
87	A node reference is a string that either simply identifies the node (for	93	A node ID is a string that uniquely identifies the node within a
88	private and slave nodes), or contains a recipe on how to reach a given	94	network. Depending on the configuration used, node IDs can look like a
89	node (for public nodes).	95	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		96	doesn't interpret node IDs in any way.
90		97
91	This recipe is simply a comma-separated list of C<address:port> pairs (for	98	=item binds - C<ip:port>
92	TCP/IP, other protocols might look different).
93		99
94	Node references come in two flavours: resolved (containing only numerical	100	Nodes can only talk to each other by creating some kind of connection to
95	addresses) or unresolved (where hostnames are used instead of addresses).	101	each other. To do this, nodes should listen on one or more local transport
		102	endpoints - binds. Currently, only standard C<ip:port> specifications can
		103	be used, which specify TCP ports to listen on.
96		104
97	Before using an unresolved node reference in a message you first have to	105	=item seeds - C<host:port>
98	resolve it.	106
		107	When a node starts, it knows nothing about the network. To teach the node
		108	about the network it first has to contact some other node within the
		109	network. This node is called a seed.
		110
		111	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		112	are expected to be long-running, and at least one of those should always
		113	be available. When nodes run out of connections (e.g. due to a network
		114	error), they try to re-establish connections to some seednodes again to
		115	join the network.
		116
		117	Apart from being sued for seeding, seednodes are not special in any way -
		118	every public node can be a seednode.
99		119
100	=back	120	=back
101		121
102	=head1 VARIABLES/FUNCTIONS	122	=head1 VARIABLES/FUNCTIONS
103		123
…		…
105		125
106	=cut	126	=cut
107		127
108	package AnyEvent::MP;	128	package AnyEvent::MP;
109		129
110	use AnyEvent::MP::Base;	130	use AnyEvent::MP::Kernel;
111		131
112	use common::sense;	132	use common::sense;
113		133
114	use Carp ();	134	use Carp ();
115		135
116	use AE ();	136	use AE ();
117		137
118	use base "Exporter";	138	use base "Exporter";
119		139
120	our $VERSION = '0.1';	140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		141
121	our @EXPORT = qw(	142	our @EXPORT = qw(
122	NODE $NODE *SELF node_of _any_	143	NODE $NODE *SELF node_of after
123	resolve_node initialise_node	144	initialise_node
124	snd rcv mon kil reg psub spawn	145	snd rcv mon mon_guard kil reg psub spawn
125	port	146	port
126	);	147	);
127		148
128	our $SELF;	149	our $SELF;
129		150
…		…
133	kil $SELF, die => $msg;	154	kil $SELF, die => $msg;
134	}	155	}
135		156
136	=item $thisnode = NODE / $NODE	157	=item $thisnode = NODE / $NODE
137		158
138	The C<NODE> function returns, and the C<$NODE> variable contains	159	The C<NODE> function returns, and the C<$NODE> variable contains, the node
139	the noderef of the local node. The value is initialised by a call	160	ID of the node running in the current process. This value is initialised by
140	to C<become_public> or C<become_slave>, after which all local port	161	a call to C<initialise_node>.
141	identifiers become invalid.
142		162
143	=item $noderef = node_of $port	163	=item $nodeid = node_of $port
144		164
145	Extracts and returns the noderef from a portid or a noderef.	165	Extracts and returns the node ID from a port ID or a node ID.
146		166
147	=item initialise_node $noderef, $seednode, $seednode...	167	=item initialise_node $profile_name, key => value...
148		168
149	=item initialise_node "slave/", $master, $master...
150
151	Before a node can talk to other nodes on the network it has to initialise	169	Before a node can talk to other nodes on the network (i.e. enter
152	itself - the minimum a node needs to know is it's own name, and optionally	170	"distributed mode") it has to initialise itself - the minimum a node needs
153	it should know the noderefs of some other nodes in the network.	171	to know is its own name, and optionally it should know the addresses of
		172	some other nodes in the network to discover other nodes.
154		173
155	This function initialises a node - it must be called exactly once (or	174	This function initialises a node - it must be called exactly once (or
156	never) before calling other AnyEvent::MP functions.	175	never) before calling other AnyEvent::MP functions.
157		176
158	All arguments are noderefs, which can be either resolved or unresolved.	177	The first argument is a profile name. If it is C<undef> or missing, then
		178	the current nodename will be used instead (i.e. F<uname -n>).
159		179
160	There are two types of networked nodes, public nodes and slave nodes:	180	The function first looks up the profile in the aemp configuration (see the
		181	L<aemp> commandline utility). the profile is calculated as follows:
161		182
162	=over 4	183	First, all remaining key => value pairs (all of which are conviniently
		184	undocumented at the moment) will be used. Then they will be overwritten by
		185	any values specified in the global default configuration (see the F<aemp>
		186	utility), then the chain of profiles selected, if any. That means that
		187	the values specified in the profile have highest priority and the values
		188	specified via C<initialise_node> have lowest priority.
163		189
164	=item public nodes	190	If the profile specifies a node ID, then this will become the node ID of
		191	this process. If not, then the profile name will be used as node ID. The
		192	special node ID of C<anon/> will be replaced by a random node ID.
165		193
166	For public nodes, C<$noderef> must either be a (possibly unresolved)	194	The next step is to look up the binds in the profile, followed by binding
167	noderef, in which case it will be resolved, or C<undef> (or missing), in	195	aemp protocol listeners on all binds specified (it is possible and valid
168	which case the noderef will be guessed.	196	to have no binds, meaning that the node cannot be contacted form the
		197	outside. This means the node cannot talk to other nodes that also have no
		198	binds, but it can still talk to all "normal" nodes).
169		199
170	Afterwards, the node will bind itself on all endpoints and try to connect	200	If the profile does not specify a binds list, then a default of C<*> is
171	to all additional C<$seednodes> that are specified. Seednodes are optional	201	used.
172	and can be used to quickly bootstrap the node into an existing network.
173		202
174	=item slave nodes	203	Lastly, the seeds list from the profile is passed to the
		204	L<AnyEvent::MP::Global> module, which will then use it to keep
		205	connectivity with at least on of those seed nodes at any point in time.
175		206
176	When the C<$noderef> is the special string C<slave/>, then the node will	207	Example: become a distributed node listening on the guessed noderef, or
177	become a slave node. Slave nodes cannot be contacted from outside and will	208	the one specified via C<aemp> for the current node. This should be the
178	route most of their traffic to the master node that they attach to.	209	most common form of invocation for "daemon"-type nodes.
179
180	At least one additional noderef is required: The node will try to connect
181	to all of them and will become a slave attached to the first node it can
182	successfully connect to.
183
184	=back
185
186	This function will block until all nodes have been resolved and, for slave
187	nodes, until it has successfully established a connection to a master
188	server.
189
190	Example: become a public node listening on the default node.
191		210
192	initialise_node;	211	initialise_node;
193		212
194	Example: become a public node, and try to contact some well-known master	213	Example: become an anonymous node. This form is often used for commandline
195	servers to become part of the network.	214	clients.
196		215
197	initialise_node undef, "master1", "master2";
198
199	Example: become a public node listening on port C<4041>.
200
201	initialise_node 4041;	216	initialise_node "anon/";
202		217
203	Example: become a public node, only visible on localhost port 4044.	218	Example: become a distributed node. If there is no profile of the given
		219	name, or no binds list was specified, resolve C<localhost:4044> and bind
		220	on the resulting addresses.
204		221
205	initialise_node "locahost:4044";	222	initialise_node "localhost:4044";
206
207	Example: become a slave node to any of the specified master servers.
208
209	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
210
211	=item $cv = resolve_node $noderef
212
213	Takes an unresolved node reference that may contain hostnames and
214	abbreviated IDs, resolves all of them and returns a resolved node
215	reference.
216
217	In addition to C<address:port> pairs allowed in resolved noderefs, the
218	following forms are supported:
219
220	=over 4
221
222	=item the empty string
223
224	An empty-string component gets resolved as if the default port (4040) was
225	specified.
226
227	=item naked port numbers (e.g. C<1234>)
228
229	These are resolved by prepending the local nodename and a colon, to be
230	further resolved.
231
232	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
233
234	These are resolved by using AnyEvent::DNS to resolve them, optionally
235	looking up SRV records for the C<aemp=4040> port, if no port was
236	specified.
237
238	=back
239		223
240	=item $SELF	224	=item $SELF
241		225
242	Contains the current port id while executing C<rcv> callbacks or C<psub>	226	Contains the current port id while executing C<rcv> callbacks or C<psub>
243	blocks.	227	blocks.
244		228
245	=item SELF, %SELF, @SELF...	229	=item *SELF, SELF, %SELF, @SELF...
246		230
247	Due to some quirks in how perl exports variables, it is impossible to	231	Due to some quirks in how perl exports variables, it is impossible to
248	just export C<$SELF>, all the symbols called C<SELF> are exported by this	232	just export C<$SELF>, all the symbols named C<SELF> are exported by this
249	module, but only C<$SELF> is currently used.	233	module, but only C<$SELF> is currently used.
250		234
251	=item snd $port, type => @data	235	=item snd $port, type => @data
252		236
253	=item snd $port, @msg	237	=item snd $port, @msg
254		238
255	Send the given message to the given port ID, which can identify either	239	Send the given message to the given port, which can identify either a
256	a local or a remote port, and can be either a string or soemthignt hat	240	local or a remote port, and must be a port ID.
257	stringifies a sa port ID (such as a port object :).
258		241
259	While the message can be about anything, it is highly recommended to use a	242	While the message can be almost anything, it is highly recommended to
260	string as first element (a portid, or some word that indicates a request	243	use a string as first element (a port ID, or some word that indicates a
261	type etc.).	244	request type etc.) and to consist if only simple perl values (scalars,
		245	arrays, hashes) - if you think you need to pass an object, think again.
262		246
263	The message data effectively becomes read-only after a call to this	247	The message data logically becomes read-only after a call to this
264	function: modifying any argument is not allowed and can cause many	248	function: modifying any argument (or values referenced by them) is
265	problems.	249	forbidden, as there can be considerable time between the call to C<snd>
		250	and the time the message is actually being serialised - in fact, it might
		251	never be copied as within the same process it is simply handed to the
		252	receiving port.
266		253
267	The type of data you can transfer depends on the transport protocol: when	254	The type of data you can transfer depends on the transport protocol: when
268	JSON is used, then only strings, numbers and arrays and hashes consisting	255	JSON is used, then only strings, numbers and arrays and hashes consisting
269	of those are allowed (no objects). When Storable is used, then anything	256	of those are allowed (no objects). When Storable is used, then anything
270	that Storable can serialise and deserialise is allowed, and for the local	257	that Storable can serialise and deserialise is allowed, and for the local
271	node, anything can be passed.	258	node, anything can be passed. Best rely only on the common denominator of
		259	these.
272		260
273	=item $local_port = port	261	=item $local_port = port
274		262
275	Create a new local port object that can be used either as a pattern	263	Create a new local port object and returns its port ID. Initially it has
276	matching port ("full port") or a single-callback port ("miniport"),	264	no callbacks set and will throw an error when it receives messages.
277	depending on how C<rcv> callbacks are bound to the object.
278		265
279	=item $port = port { my @msg = @_; $finished }	266	=item $local_port = port { my @msg = @_ }
280		267
281	Creates a "miniport", that is, a very lightweight port without any pattern	268	Creates a new local port, and returns its ID. Semantically the same as
282	matching behind it, and returns its ID. Semantically the same as creating
283	a port and calling C<rcv $port, $callback> on it.	269	creating a port and calling C<rcv $port, $callback> on it.
284		270
285	The block will be called for every message received on the port. When the	271	The block will be called for every message received on the port, with the
286	callback returns a true value its job is considered "done" and the port	272	global variable C<$SELF> set to the port ID. Runtime errors will cause the
287	will be destroyed. Otherwise it will stay alive.	273	port to be C<kil>ed. The message will be passed as-is, no extra argument
		274	(i.e. no port ID) will be passed to the callback.
288		275
289	The message will be passed as-is, no extra argument (i.e. no port id) will	276	If you want to stop/destroy the port, simply C<kil> it:
290	be passed to the callback.
291		277
292	If you need the local port id in the callback, this works nicely:	278	my $port = port {
293		279	my @msg = @_;
294	my $port; $port = port {	280	...
295	snd $otherport, reply => $port;	281	kil $SELF;
296	};	282	};
297		283
298	=cut	284	=cut
299		285
300	sub rcv($@);	286	sub rcv($@);
		287
		288	sub _kilme {
		289	die "received message on port without callback";
		290	}
301		291
302	sub port(;&) {	292	sub port(;&) {
303	my $id = "$UNIQ." . $ID++;	293	my $id = "$UNIQ." . $ID++;
304	my $port = "$NODE#$id";	294	my $port = "$NODE#$id";
305		295
306	if (@_) {	296	rcv $port, shift \|\| \&_kilme;
307	rcv $port, shift;
308	} else {
309	$PORT{$id} = sub { }; # nop
310	}
311		297
312	$port	298	$port
313	}	299	}
314		300
315	=item reg $port, $name
316
317	=item reg $name
318
319	Registers the given port (or C<$SELF><<< if missing) under the name
320	C<$name>. If the name already exists it is replaced.
321
322	A port can only be registered under one well known name.
323
324	A port automatically becomes unregistered when it is killed.
325
326	=cut
327
328	sub reg(@) {
329	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
330
331	$REG{$_[0]} = $port;
332	}
333
334	=item rcv $port, $callback->(@msg)	301	=item rcv $local_port, $callback->(@msg)
335		302
336	Replaces the callback on the specified miniport (after converting it to	303	Replaces the default callback on the specified port. There is no way to
337	one if required).	304	remove the default callback: use C<sub { }> to disable it, or better
338		305	C<kil> the port when it is no longer needed.
339	=item rcv $port, tagstring => $callback->(@msg), ...
340
341	=item rcv $port, $smartmatch => $callback->(@msg), ...
342
343	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
344
345	Register callbacks to be called on matching messages on the given full
346	port (after converting it to one if required) and return the port.
347
348	The callback has to return a true value when its work is done, after
349	which is will be removed, or a false value in which case it will stay
350	registered.
351		306
352	The global C<$SELF> (exported by this module) contains C<$port> while	307	The global C<$SELF> (exported by this module) contains C<$port> while
353	executing the callback.	308	executing the callback. Runtime errors during callback execution will
		309	result in the port being C<kil>ed.
354		310
355	Runtime errors during callback execution will result in the port being	311	The default callback received all messages not matched by a more specific
356	C<kil>ed.	312	C<tag> match.
357		313
358	If the match is an array reference, then it will be matched against the	314	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
359	first elements of the message, otherwise only the first element is being
360	matched.
361		315
362	Any element in the match that is specified as C<_any_> (a function	316	Register (or replace) callbacks to be called on messages starting with the
363	exported by this module) matches any single element of the message.	317	given tag on the given port (and return the port), or unregister it (when
		318	C<$callback> is C<$undef> or missing). There can only be one callback
		319	registered for each tag.
364		320
365	While not required, it is highly recommended that the first matching	321	The original message will be passed to the callback, after the first
366	element is a string identifying the message. The one-string-only match is	322	element (the tag) has been removed. The callback will use the same
367	also the most efficient match (by far).	323	environment as the default callback (see above).
368		324
369	Example: create a port and bind receivers on it in one go.	325	Example: create a port and bind receivers on it in one go.
370		326
371	my $port = rcv port,	327	my $port = rcv port,
372	msg1 => sub { ...; 0 },	328	msg1 => sub { ... },
373	msg2 => sub { ...; 0 },	329	msg2 => sub { ... },
374	;	330	;
375		331
376	Example: create a port, bind receivers and send it in a message elsewhere	332	Example: create a port, bind receivers and send it in a message elsewhere
377	in one go:	333	in one go:
378		334
379	snd $otherport, reply =>	335	snd $otherport, reply =>
380	rcv port,	336	rcv port,
381	msg1 => sub { ...; 0 },	337	msg1 => sub { ... },
382	...	338	...
383	;	339	;
		340
		341	Example: temporarily register a rcv callback for a tag matching some port
		342	(e.g. for a rpc reply) and unregister it after a message was received.
		343
		344	rcv $port, $otherport => sub {
		345	my @reply = @_;
		346
		347	rcv $SELF, $otherport;
		348	};
384		349
385	=cut	350	=cut
386		351
387	sub rcv($@) {	352	sub rcv($@) {
388	my $port = shift;	353	my $port = shift;
389	my ($noderef, $portid) = split /#/, $port, 2;	354	my ($noderef, $portid) = split /#/, $port, 2;
390		355
391	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	356	$NODE{$noderef} == $NODE{""}
392	or Carp::croak "$port: rcv can only be called on local ports, caught";	357	or Carp::croak "$port: rcv can only be called on local ports, caught";
393		358
394	if (@_ == 1) {	359	while (@_) {
		360	if (ref $_[0]) {
		361	if (my $self = $PORT_DATA{$portid}) {
		362	"AnyEvent::MP::Port" eq ref $self
		363	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		364
		365	$self->[2] = shift;
		366	} else {
395	my $cb = shift;	367	my $cb = shift;
396	delete $PORT_DATA{$portid};
397	$PORT{$portid} = sub {	368	$PORT{$portid} = sub {
398	local $SELF = $port;	369	local $SELF = $port;
399	eval {	370	eval { &$cb }; _self_die if $@;
400	&$cb	371	};
401	and kil $port;
402	};	372	}
403	_self_die if $@;	373	} elsif (defined $_[0]) {
404	};
405	} else {
406	my $self = $PORT_DATA{$portid} \|\|= do {	374	my $self = $PORT_DATA{$portid} \|\|= do {
407	my $self = bless {	375	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
408	id => $port,
409	}, "AnyEvent::MP::Port";
410		376
411	$PORT{$portid} = sub {	377	$PORT{$portid} = sub {
412	local $SELF = $port;	378	local $SELF = $port;
413		379
414	eval {
415	for (@{ $self->{rc0}{$_[0]} }) {	380	if (my $cb = $self->[1]{$_[0]}) {
416	$_ && &{$_->[0]}	381	shift;
417	&& undef $_;	382	eval { &$cb }; _self_die if $@;
418	}	383	} else {
419
420	for (@{ $self->{rcv}{$_[0]} }) {
421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
422	&& &{$_->[0]}	384	&{ $self->[0] };
423	&& undef $_;
424	}
425
426	for (@{ $self->{any} }) {
427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
428	&& &{$_->[0]}
429	&& undef $_;
430	}	385	}
431	};	386	};
432	_self_die if $@;	387
		388	$self
433	};	389	};
434		390
435	$self
436	};
437
438	"AnyEvent::MP::Port" eq ref $self	391	"AnyEvent::MP::Port" eq ref $self
439	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	392	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
440		393
441	while (@_) {
442	my ($match, $cb) = splice @_, 0, 2;	394	my ($tag, $cb) = splice @_, 0, 2;
443		395
444	if (!ref $match) {	396	if (defined $cb) {
445	push @{ $self->{rc0}{$match} }, [$cb];	397	$self->[1]{$tag} = $cb;
446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
447	my ($type, @match) = @$match;
448	@match
449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
451	} else {	398	} else {
452	push @{ $self->{any} }, [$cb, $match];	399	delete $self->[1]{$tag};
453	}	400	}
454	}	401	}
455	}	402	}
456		403
457	$port	404	$port
…		…
493	$res	440	$res
494	}	441	}
495	}	442	}
496	}	443	}
497		444
498	=item $guard = mon $port, $cb->(@reason)	445	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
499		446
500	=item $guard = mon $port, $rcvport	447	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
501		448
502	=item $guard = mon $port	449	=item $guard = mon $port # kill $SELF when $port dies
503		450
504	=item $guard = mon $port, $rcvport, @msg	451	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
505		452
506	Monitor the given port and do something when the port is killed, and	453	Monitor the given port and do something when the port is killed or
507	optionally return a guard that can be used to stop monitoring again.	454	messages to it were lost, and optionally return a guard that can be used
		455	to stop monitoring again.
		456
		457	C<mon> effectively guarantees that, in the absence of hardware failures,
		458	after starting the monitor, either all messages sent to the port will
		459	arrive, or the monitoring action will be invoked after possible message
		460	loss has been detected. No messages will be lost "in between" (after
		461	the first lost message no further messages will be received by the
		462	port). After the monitoring action was invoked, further messages might get
		463	delivered again.
		464
		465	Note that monitoring-actions are one-shot: once messages are lost (and a
		466	monitoring alert was raised), they are removed and will not trigger again.
508		467
509	In the first form (callback), the callback is simply called with any	468	In the first form (callback), the callback is simply called with any
510	number of C<@reason> elements (no @reason means that the port was deleted	469	number of C<@reason> elements (no @reason means that the port was deleted
511	"normally"). Note also that I<< the callback B<must> never die >>, so use	470	"normally"). Note also that I<< the callback B<must> never die >>, so use
512	C<eval> if unsure.	471	C<eval> if unsure.
513		472
514	In the second form (another port given), the other port (C<$rcvport)	473	In the second form (another port given), the other port (C<$rcvport>)
515	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	474	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
516	"normal" kils nothing happens, while under all other conditions, the other	475	"normal" kils nothing happens, while under all other conditions, the other
517	port is killed with the same reason.	476	port is killed with the same reason.
518		477
519	The third form (kill self) is the same as the second form, except that	478	The third form (kill self) is the same as the second form, except that
…		…
546	sub mon {	505	sub mon {
547	my ($noderef, $port) = split /#/, shift, 2;	506	my ($noderef, $port) = split /#/, shift, 2;
548		507
549	my $node = $NODE{$noderef} \|\| add_node $noderef;	508	my $node = $NODE{$noderef} \|\| add_node $noderef;
550		509
551	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	510	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
552		511
553	unless (ref $cb) {	512	unless (ref $cb) {
554	if (@_) {	513	if (@_) {
555	# send a kill info message	514	# send a kill info message
556	my (@msg) = @_;	515	my (@msg) = ($cb, @_);
557	$cb = sub { snd @msg, @_ };	516	$cb = sub { snd @msg, @_ };
558	} else {	517	} else {
559	# simply kill other port	518	# simply kill other port
560	my $port = $cb;	519	my $port = $cb;
561	$cb = sub { kil $port, @_ if @_ };	520	$cb = sub { kil $port, @_ if @_ };
…		…
574	is killed, the references will be freed.	533	is killed, the references will be freed.
575		534
576	Optionally returns a guard that will stop the monitoring.	535	Optionally returns a guard that will stop the monitoring.
577		536
578	This function is useful when you create e.g. timers or other watchers and	537	This function is useful when you create e.g. timers or other watchers and
579	want to free them when the port gets killed:	538	want to free them when the port gets killed (note the use of C<psub>):
580		539
581	$port->rcv (start => sub {	540	$port->rcv (start => sub {
582	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	541	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
583	undef $timer if 0.9 < rand;	542	undef $timer if 0.9 < rand;
584	});	543	});
585	});	544	});
586		545
587	=cut	546	=cut
…		…
596		555
597	=item kil $port[, @reason]	556	=item kil $port[, @reason]
598		557
599	Kill the specified port with the given C<@reason>.	558	Kill the specified port with the given C<@reason>.
600		559
601	If no C<@reason> is specified, then the port is killed "normally" (linked	560	If no C<@reason> is specified, then the port is killed "normally" (ports
602	ports will not be kileld, or even notified).	561	monitoring other ports will not necessarily die because a port dies
		562	"normally").
603		563
604	Otherwise, linked ports get killed with the same reason (second form of	564	Otherwise, linked ports get killed with the same reason (second form of
605	C<mon>, see below).	565	C<mon>, see above).
606		566
607	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	567	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
608	will be reported as reason C<< die => $@ >>.	568	will be reported as reason C<< die => $@ >>.
609		569
610	Transport/communication errors are reported as C<< transport_error =>	570	Transport/communication errors are reported as C<< transport_error =>
…		…
615	=item $port = spawn $node, $initfunc[, @initdata]	575	=item $port = spawn $node, $initfunc[, @initdata]
616		576
617	Creates a port on the node C<$node> (which can also be a port ID, in which	577	Creates a port on the node C<$node> (which can also be a port ID, in which
618	case it's the node where that port resides).	578	case it's the node where that port resides).
619		579
620	The port ID of the newly created port is return immediately, and it is	580	The port ID of the newly created port is returned immediately, and it is
621	permissible to immediately start sending messages or monitor the port.	581	possible to immediately start sending messages or to monitor the port.
622		582
623	After the port has been created, the init function is	583	After the port has been created, the init function is called on the remote
624	called. This fucntion must be a fully-qualified function name	584	node, in the same context as a C<rcv> callback. This function must be a
625	(e.g. C<MyApp::Chat::Server::init>).	585	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		586	specify a function in the main program, use C<::name>.
626		587
627	If the function doesn't exist, then the node tries to C<require>	588	If the function doesn't exist, then the node tries to C<require>
628	the package, then the package above the package and so on (e.g.	589	the package, then the package above the package and so on (e.g.
629	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	590	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
630	exists or it runs out of package names.	591	exists or it runs out of package names.
631		592
632	The init function is then called with the newly-created port as context	593	The init function is then called with the newly-created port as context
633	object (C<$SELF>) and the C<@initdata> values as arguments.	594	object (C<$SELF>) and the C<@initdata> values as arguments.
634		595
635	A common idiom is to pass your own port, monitor the spawned port, and	596	A common idiom is to pass a local port, immediately monitor the spawned
636	in the init function, monitor the original port. This two-way monitoring	597	port, and in the remote init function, immediately monitor the passed
637	ensures that both ports get cleaned up when there is a problem.	598	local port. This two-way monitoring ensures that both ports get cleaned up
		599	when there is a problem.
638		600
639	Example: spawn a chat server port on C<$othernode>.	601	Example: spawn a chat server port on C<$othernode>.
640		602
641	# this node, executed from within a port context:	603	# this node, executed from within a port context:
642	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	604	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
669	sub spawn(@) {	631	sub spawn(@) {
670	my ($noderef, undef) = split /#/, shift, 2;	632	my ($noderef, undef) = split /#/, shift, 2;
671		633
672	my $id = "$RUNIQ." . $ID++;	634	my $id = "$RUNIQ." . $ID++;
673		635
674	($NODE{$noderef} \|\| add_node $noderef)	636	$_[0] =~ /::/
675	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);	637	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		638
		639	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
676		640
677	"$noderef#$id"	641	"$noderef#$id"
678	}	642	}
679		643
680	=back	644	=item after $timeout, @msg
681		645
682	=head1 NODE MESSAGES	646	=item after $timeout, $callback
683		647
684	Nodes understand the following messages sent to them. Many of them take	648	Either sends the given message, or call the given callback, after the
685	arguments called C<@reply>, which will simply be used to compose a reply	649	specified number of seconds.
686	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
687	the remaining arguments are simply the message data.
688		650
689	While other messages exist, they are not public and subject to change.	651	This is simply a utility function that comes in handy at times - the
		652	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		653	so it may go away in the future.
690		654
691	=over 4
692
693	=cut	655	=cut
694		656
695	=item lookup => $name, @reply	657	sub after($@) {
		658	my ($timeout, @action) = @_;
696		659
697	Replies with the port ID of the specified well-known port, or C<undef>.	660	my $t; $t = AE::timer $timeout, 0, sub {
698		661	undef $t;
699	=item devnull => ...	662	ref $action[0]
700		663	? $action[0]()
701	Generic data sink/CPU heat conversion.	664	: snd @action;
702		665	};
703	=item relay => $port, @msg	666	}
704
705	Simply forwards the message to the given port.
706
707	=item eval => $string[ @reply]
708
709	Evaluates the given string. If C<@reply> is given, then a message of the
710	form C<@reply, $@, @evalres> is sent.
711
712	Example: crash another node.
713
714	snd $othernode, eval => "exit";
715
716	=item time => @reply
717
718	Replies the the current node time to C<@reply>.
719
720	Example: tell the current node to send the current time to C<$myport> in a
721	C<timereply> message.
722
723	snd $NODE, time => $myport, timereply => 1, 2;
724	# => snd $myport, timereply => 1, 2, <time>
725		667
726	=back	668	=back
727		669
728	=head1 AnyEvent::MP vs. Distributed Erlang	670	=head1 AnyEvent::MP vs. Distributed Erlang
729		671
…		…
739		681
740	Despite the similarities, there are also some important differences:	682	Despite the similarities, there are also some important differences:
741		683
742	=over 4	684	=over 4
743		685
744	=item * Node references contain the recipe on how to contact them.	686	=item * Node IDs are arbitrary strings in AEMP.
745		687
746	Erlang relies on special naming and DNS to work everywhere in the	688	Erlang relies on special naming and DNS to work everywhere in the same
747	same way. AEMP relies on each node knowing it's own address(es), with	689	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
748	convenience functionality.	690	configuraiton or DNS), but will otherwise discover other odes itself.
749		691
750	This means that AEMP requires a less tightly controlled environment at the	692	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
751	cost of longer node references and a slightly higher management overhead.	693	uses "local ports are like remote ports".
		694
		695	The failure modes for local ports are quite different (runtime errors
		696	only) then for remote ports - when a local port dies, you I<know> it dies,
		697	when a connection to another node dies, you know nothing about the other
		698	port.
		699
		700	Erlang pretends remote ports are as reliable as local ports, even when
		701	they are not.
		702
		703	AEMP encourages a "treat remote ports differently" philosophy, with local
		704	ports being the special case/exception, where transport errors cannot
		705	occur.
752		706
753	=item * Erlang uses processes and a mailbox, AEMP does not queue.	707	=item * Erlang uses processes and a mailbox, AEMP does not queue.
754		708
755	Erlang uses processes that selctively receive messages, and therefore	709	Erlang uses processes that selectively receive messages, and therefore
756	needs a queue. AEMP is event based, queuing messages would serve no useful	710	needs a queue. AEMP is event based, queuing messages would serve no
757	purpose.	711	useful purpose. For the same reason the pattern-matching abilities of
		712	AnyEvent::MP are more limited, as there is little need to be able to
		713	filter messages without dequeing them.
758		714
759	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	715	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
760		716
761	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	717	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
762		718
763	Sending messages in Erlang is synchronous and blocks the process. AEMP	719	Sending messages in Erlang is synchronous and blocks the process (and
764	sends are immediate, connection establishment is handled in the	720	so does not need a queue that can overflow). AEMP sends are immediate,
765	background.	721	connection establishment is handled in the background.
766		722
767	=item * Erlang can silently lose messages, AEMP cannot.	723	=item * Erlang suffers from silent message loss, AEMP does not.
768		724
769	Erlang makes few guarantees on messages delivery - messages can get lost	725	Erlang makes few guarantees on messages delivery - messages can get lost
770	without any of the processes realising it (i.e. you send messages a, b,	726	without any of the processes realising it (i.e. you send messages a, b,
771	and c, and the other side only receives messages a and c).	727	and c, and the other side only receives messages a and c).
772		728
773	AEMP guarantees correct ordering, and the guarantee that there are no	729	AEMP guarantees correct ordering, and the guarantee that after one message
774	holes in the message sequence.	730	is lost, all following ones sent to the same port are lost as well, until
775		731	monitoring raises an error, so there are no silent "holes" in the message
776	=item * In Erlang, processes can be declared dead and later be found to be	732	sequence.
777	alive.
778
779	In Erlang it can happen that a monitored process is declared dead and
780	linked processes get killed, but later it turns out that the process is
781	still alive - and can receive messages.
782
783	In AEMP, when port monitoring detects a port as dead, then that port will
784	eventually be killed - it cannot happen that a node detects a port as dead
785	and then later sends messages to it, finding it is still alive.
786		733
787	=item * Erlang can send messages to the wrong port, AEMP does not.	734	=item * Erlang can send messages to the wrong port, AEMP does not.
788		735
789	In Erlang it is quite possible that a node that restarts reuses a process	736	In Erlang it is quite likely that a node that restarts reuses a process ID
790	ID known to other nodes for a completely different process, causing	737	known to other nodes for a completely different process, causing messages
791	messages destined for that process to end up in an unrelated process.	738	destined for that process to end up in an unrelated process.
792		739
793	AEMP never reuses port IDs, so old messages or old port IDs floating	740	AEMP never reuses port IDs, so old messages or old port IDs floating
794	around in the network will not be sent to an unrelated port.	741	around in the network will not be sent to an unrelated port.
795		742
796	=item * Erlang uses unprotected connections, AEMP uses secure	743	=item * Erlang uses unprotected connections, AEMP uses secure
797	authentication and can use TLS.	744	authentication and can use TLS.
798		745
799	AEMP can use a proven protocol - SSL/TLS - to protect connections and	746	AEMP can use a proven protocol - TLS - to protect connections and
800	securely authenticate nodes.	747	securely authenticate nodes.
801		748
802	=item * The AEMP protocol is optimised for both text-based and binary	749	=item * The AEMP protocol is optimised for both text-based and binary
803	communications.	750	communications.
804		751
805	The AEMP protocol, unlike the Erlang protocol, supports both	752	The AEMP protocol, unlike the Erlang protocol, supports both programming
806	language-independent text-only protocols (good for debugging) and binary,	753	language independent text-only protocols (good for debugging) and binary,
807	language-specific serialisers (e.g. Storable).	754	language-specific serialisers (e.g. Storable). By default, unless TLS is
		755	used, the protocol is actually completely text-based.
808		756
809	It has also been carefully designed to be implementable in other languages	757	It has also been carefully designed to be implementable in other languages
810	with a minimum of work while gracefully degrading fucntionality to make the	758	with a minimum of work while gracefully degrading functionality to make the
811	protocol simple.	759	protocol simple.
812		760
813	=item * AEMP has more flexible monitoring options than Erlang.	761	=item * AEMP has more flexible monitoring options than Erlang.
814		762
815	In Erlang, you can chose to receive I<all> exit signals as messages	763	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
818	Erlang, as one can choose between automatic kill, exit message or callback	766	Erlang, as one can choose between automatic kill, exit message or callback
819	on a per-process basis.	767	on a per-process basis.
820		768
821	=item * Erlang tries to hide remote/local connections, AEMP does not.	769	=item * Erlang tries to hide remote/local connections, AEMP does not.
822		770
823	Monitoring in Erlang is not an indicator of process death/crashes,	771	Monitoring in Erlang is not an indicator of process death/crashes, in the
824	as linking is (except linking is unreliable in Erlang).	772	same way as linking is (except linking is unreliable in Erlang).
825		773
826	In AEMP, you don't "look up" registered port names or send to named ports	774	In AEMP, you don't "look up" registered port names or send to named ports
827	that might or might not be persistent. Instead, you normally spawn a port	775	that might or might not be persistent. Instead, you normally spawn a port
828	on the remote node. The init function monitors the you, and you monitor	776	on the remote node. The init function monitors you, and you monitor the
829	the remote port. Since both monitors are local to the node, they are much	777	remote port. Since both monitors are local to the node, they are much more
830	more reliable.	778	reliable (no need for C<spawn_link>).
831		779
832	This also saves round-trips and avoids sending messages to the wrong port	780	This also saves round-trips and avoids sending messages to the wrong port
833	(hard to do in Erlang).	781	(hard to do in Erlang).
834		782
835	=back	783	=back
836		784
		785	=head1 RATIONALE
		786
		787	=over 4
		788
		789	=item Why strings for port and node IDs, why not objects?
		790
		791	We considered "objects", but found that the actual number of methods
		792	that can be called are quite low. Since port and node IDs travel over
		793	the network frequently, the serialising/deserialising would add lots of
		794	overhead, as well as having to keep a proxy object everywhere.
		795
		796	Strings can easily be printed, easily serialised etc. and need no special
		797	procedures to be "valid".
		798
		799	And as a result, a miniport consists of a single closure stored in a
		800	global hash - it can't become much cheaper.
		801
		802	=item Why favour JSON, why not a real serialising format such as Storable?
		803
		804	In fact, any AnyEvent::MP node will happily accept Storable as framing
		805	format, but currently there is no way to make a node use Storable by
		806	default (although all nodes will accept it).
		807
		808	The default framing protocol is JSON because a) JSON::XS is many times
		809	faster for small messages and b) most importantly, after years of
		810	experience we found that object serialisation is causing more problems
		811	than it solves: Just like function calls, objects simply do not travel
		812	easily over the network, mostly because they will always be a copy, so you
		813	always have to re-think your design.
		814
		815	Keeping your messages simple, concentrating on data structures rather than
		816	objects, will keep your messages clean, tidy and efficient.
		817
		818	=back
		819
837	=head1 SEE ALSO	820	=head1 SEE ALSO
		821
		822	L<AnyEvent::MP::Intro> - a gentle introduction.
		823
		824	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		825
		826	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		827	your applications.
838		828
839	L<AnyEvent>.	829	L<AnyEvent>.
840		830
841	=head1 AUTHOR	831	=head1 AUTHOR
842		832

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC vs. Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC vs.
Revision 1.70 by root, Sun Aug 30 19:49:47 2009 UTC