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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.66 by root, Fri Aug 28 01:07:24 2009 UTC

…		…
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		14
15	# initialise the node so it can send/receive messages	15	# initialise the node so it can send/receive messages
16	initialise_node; # -OR-	16	initialise_node;
17	initialise_node "localhost:4040"; # -OR-
18	initialise_node "slave/", "localhost:4040"
19		17
20	# ports are message endpoints	18	# ports are message endpoints
21		19
22	# sending messages	20	# sending messages
23	snd $port, type => data...;	21	snd $port, type => data...;
24	snd $port, @msg;	22	snd $port, @msg;
25	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
26		24
27	# creating/using miniports	25	# creating/using ports, the simple way
28	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
29		27
30	# creating/using full ports	28	# creating/using ports, tagged message matching
31	my $port = port;	29	my $port = port;
32	rcv $port, smartmatch => $cb->(@msg);
33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
34	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n"; 0 };
35
36	# more, smarter, matches (_any_ is exported by this module)
37	rcv $port, [child_died => $pid] => sub { ...
38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
39		32
40	# create a port on another node	33	# create a port on another node
41	my $port = spawn $node, $initfunc, @initdata;	34	my $port = spawn $node, $initfunc, @initdata;
42		35
43	# monitoring	36	# monitoring
…		…
74		67
75	=item port	68	=item port
76		69
77	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).
78		71
79	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
80	messages. All C<rcv> handlers will receive messages they match, messages	73	some messages. Messages send to ports will not be queued, regardless of
81	will not be queued.	74	anything was listening for them or not.
82		75
83	=item port id - C<noderef#portname>	76	=item port ID - C<noderef#portname>
84		77
85	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	78	A port ID is the concatenation of a noderef, a hash-mark (C<#>) as
86	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format). An
87	exception is the the node port, whose ID is identical to its node	80	exception is the the node port, whose ID is identical to its node
88	reference.	81	reference.
89		82
90	=item node	83	=item node
91		84
92	A node is a single process containing at least one port - the node	85	A node is a single process containing at least one port - the node port,
93	port. You can send messages to node ports to find existing ports or to	86	which provides nodes to manage each other remotely, and to create new
94	create new ports, among other things.	87	ports.
95		88
96	Nodes are either private (single-process only), slaves (connected to a	89	Nodes are either private (single-process only), slaves (can only talk to
97	master node only) or public nodes (connectable from unrelated nodes).	90	public nodes, but do not need an open port) or public nodes (connectable
		91	from any other node).
98		92
99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	93	=item node ID - C<[a-za-Z0-9_\-.:]+>
100		94
101	A node reference is a string that either simply identifies the node (for	95	A node ID is a string that uniquely identifies the node within a
102	private and slave nodes), or contains a recipe on how to reach a given	96	network. Depending on the configuration used, node IDs can look like a
103	node (for public nodes).	97	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		98	doesn't interpret node IDs in any way.
104		99
105	This recipe is simply a comma-separated list of C<address:port> pairs (for	100	=item binds - C<ip:port>
106	TCP/IP, other protocols might look different).
107		101
108	Node references come in two flavours: resolved (containing only numerical	102	Nodes can only talk to each other by creating some kind of connection to
109	addresses) or unresolved (where hostnames are used instead of addresses).	103	each other. To do this, nodes should listen on one or more local transport
		104	endpoints - binds. Currently, only standard C<ip:port> specifications can
		105	be used, which specify TCP ports to listen on.
110		106
111	Before using an unresolved node reference in a message you first have to	107	=item seeds - C<host:port>
112	resolve it.	108
		109	When a node starts, it knows nothing about the network. To teach the node
		110	about the network it first has to contact some other node within the
		111	network. This node is called a seed.
		112
		113	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		114	are expected to be long-running, and at least one of those should always
		115	be available. When nodes run out of connections (e.g. due to a network
		116	error), they try to re-establish connections to some seednodes again to
		117	join the network.
113		118
114	=back	119	=back
115		120
116	=head1 VARIABLES/FUNCTIONS	121	=head1 VARIABLES/FUNCTIONS
117		122
…		…
132	use base "Exporter";	137	use base "Exporter";
133		138
134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	139	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
135		140
136	our @EXPORT = qw(	141	our @EXPORT = qw(
137	NODE $NODE *SELF node_of _any_	142	NODE $NODE *SELF node_of after
138	resolve_node initialise_node	143	resolve_node initialise_node
139	snd rcv mon kil reg psub spawn	144	snd rcv mon mon_guard kil reg psub spawn
140	port	145	port
141	);	146	);
142		147
143	our $SELF;	148	our $SELF;
144		149
…		…
148	kil $SELF, die => $msg;	153	kil $SELF, die => $msg;
149	}	154	}
150		155
151	=item $thisnode = NODE / $NODE	156	=item $thisnode = NODE / $NODE
152		157
153	The C<NODE> function returns, and the C<$NODE> variable contains	158	The C<NODE> function returns, and the C<$NODE> variable contains the node
154	the noderef of the local node. The value is initialised by a call	159	ID of the node running in the current process. This value is initialised by
155	to C<become_public> or C<become_slave>, after which all local port	160	a call to C<initialise_node>.
156	identifiers become invalid.
157		161
158	=item $noderef = node_of $port	162	=item $nodeid = node_of $port
159		163
160	Extracts and returns the noderef from a portid or a noderef.	164	Extracts and returns the node ID part from a port ID or a node ID.
161		165
162	=item initialise_node $noderef, $seednode, $seednode...	166	=item initialise_node $profile_name
163		167
164	=item initialise_node "slave/", $master, $master...
165
166	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
167	itself - the minimum a node needs to know is it's own name, and optionally	169	"distributed mode") it has to initialise itself - the minimum a node needs
168	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.
169		172
170	This function initialises a node - it must be called exactly once (or	173	This function initialises a node - it must be called exactly once (or
171	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
172		175
173	All arguments (optionally except for the first) are noderefs, which can be	176	The first argument is a profile name. If it is C<undef> or missing, then
174	either resolved or unresolved.	177	the current nodename will be used instead (i.e. F<uname -n>).
175		178
176	The first argument will be looked up in the configuration database first	179	The function then looks up the profile in the aemp configuration (see the
177	(if it is C<undef> then the current nodename will be used instead) to find	180	L<aemp> commandline utility).
178	the relevant configuration profile (see L<aemp>). If none is found then
179	the default configuration is used. The configuration supplies additional
180	seed/master nodes and can override the actual noderef.
181		181
182	There are two types of networked nodes, public nodes and slave nodes:	182	If the profile specifies a node ID, then this will become the node ID of
		183	this process. If not, then the profile name will be used as node ID. The
		184	special node ID of C<anon/> will be replaced by a random node ID.
183		185
184	=over 4	186	The next step is to look up the binds in the profile, followed by binding
		187	aemp protocol listeners on all binds specified (it is possible and valid
		188	to have no binds, meaning that the node cannot be contacted form the
		189	outside. This means the node cannot talk to other nodes that also have no
		190	binds, but it can still talk to all "normal" nodes).
185		191
186	=item public nodes	192	If the profile does not specify a binds list, then the node ID will be
		193	treated as if it were of the form C<host:port>, which will be resolved and
		194	used as binds list.
187		195
188	For public nodes, C<$noderef> (supplied either directly to	196	Lastly, the seeds list from the profile is passed to the
189	C<initialise_node> or indirectly via a profile or the nodename) must be a	197	L<AnyEvent::MP::Global> module, which will then use it to keep
190	noderef (possibly unresolved, in which case it will be resolved).	198	connectivity with at least on of those seed nodes at any point in time.
191		199
192	After resolving, the node will bind itself on all endpoints and try to
193	connect to all additional C<$seednodes> that are specified. Seednodes are
194	optional and can be used to quickly bootstrap the node into an existing
195	network.
196
197	=item slave nodes
198
199	When the C<$noderef> (either as given or overriden by the config file)
200	is the special string C<slave/>, then the node will become a slave
201	node. Slave nodes cannot be contacted from outside and will route most of
202	their traffic to the master node that they attach to.
203
204	At least one additional noderef is required (either by specifying it
205	directly or because it is part of the configuration profile): The node
206	will try to connect to all of them and will become a slave attached to the
207	first node it can successfully connect to.
208
209	=back
210
211	This function will block until all nodes have been resolved and, for slave
212	nodes, until it has successfully established a connection to a master
213	server.
214
215	Example: become a public node listening on the guessed noderef, or the one	200	Example: become a distributed node listening on the guessed noderef, or
216	specified via C<aemp> for the current node. This should be the most common	201	the one specified via C<aemp> for the current node. This should be the
217	form of invocation for "daemon"-type nodes.	202	most common form of invocation for "daemon"-type nodes.
218		203
219	initialise_node;	204	initialise_node;
220		205
221	Example: become a slave node to any of the the seednodes specified via	206	Example: become an anonymous node. This form is often used for commandline
222	C<aemp>. This form is often used for commandline clients.	207	clients.
223		208
224	initialise_node "slave/";	209	initialise_node "anon/";
225		210
226	Example: become a slave node to any of the specified master servers. This	211	Example: become a distributed node. If there is no profile of the given
227	form is also often used for commandline clients.	212	name, or no binds list was specified, resolve C<localhost:4044> and bind
228		213	on the resulting addresses.
229	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
230
231	Example: become a public node, and try to contact some well-known master
232	servers to become part of the network.
233
234	initialise_node undef, "master1", "master2";
235
236	Example: become a public node listening on port C<4041>.
237
238	initialise_node 4041;
239
240	Example: become a public node, only visible on localhost port 4044.
241		214
242	initialise_node "localhost:4044";	215	initialise_node "localhost:4044";
243
244	=item $cv = resolve_node $noderef
245
246	Takes an unresolved node reference that may contain hostnames and
247	abbreviated IDs, resolves all of them and returns a resolved node
248	reference.
249
250	In addition to C<address:port> pairs allowed in resolved noderefs, the
251	following forms are supported:
252
253	=over 4
254
255	=item the empty string
256
257	An empty-string component gets resolved as if the default port (4040) was
258	specified.
259
260	=item naked port numbers (e.g. C<1234>)
261
262	These are resolved by prepending the local nodename and a colon, to be
263	further resolved.
264
265	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
266
267	These are resolved by using AnyEvent::DNS to resolve them, optionally
268	looking up SRV records for the C<aemp=4040> port, if no port was
269	specified.
270
271	=back
272		216
273	=item $SELF	217	=item $SELF
274		218
275	Contains the current port id while executing C<rcv> callbacks or C<psub>	219	Contains the current port id while executing C<rcv> callbacks or C<psub>
276	blocks.	220	blocks.
…		…
284	=item snd $port, type => @data	228	=item snd $port, type => @data
285		229
286	=item snd $port, @msg	230	=item snd $port, @msg
287		231
288	Send the given message to the given port ID, which can identify either	232	Send the given message to the given port ID, which can identify either
289	a local or a remote port, and can be either a string or soemthignt hat	233	a local or a remote port, and must be a port ID.
290	stringifies a sa port ID (such as a port object :).
291		234
292	While the message can be about anything, it is highly recommended to use a	235	While the message can be about anything, it is highly recommended to use a
293	string as first element (a portid, or some word that indicates a request	236	string as first element (a port ID, or some word that indicates a request
294	type etc.).	237	type etc.).
295		238
296	The message data effectively becomes read-only after a call to this	239	The message data effectively becomes read-only after a call to this
297	function: modifying any argument is not allowed and can cause many	240	function: modifying any argument is not allowed and can cause many
298	problems.	241	problems.
…		…
303	that Storable can serialise and deserialise is allowed, and for the local	246	that Storable can serialise and deserialise is allowed, and for the local
304	node, anything can be passed.	247	node, anything can be passed.
305		248
306	=item $local_port = port	249	=item $local_port = port
307		250
308	Create a new local port object that can be used either as a pattern	251	Create a new local port object and returns its port ID. Initially it has
309	matching port ("full port") or a single-callback port ("miniport"),	252	no callbacks set and will throw an error when it receives messages.
310	depending on how C<rcv> callbacks are bound to the object.
311		253
312	=item $port = port { my @msg = @_; $finished }	254	=item $local_port = port { my @msg = @_ }
313		255
314	Creates a "miniport", that is, a very lightweight port without any pattern	256	Creates a new local port, and returns its ID. Semantically the same as
315	matching behind it, and returns its ID. Semantically the same as creating
316	a port and calling C<rcv $port, $callback> on it.	257	creating a port and calling C<rcv $port, $callback> on it.
317		258
318	The block will be called for every message received on the port. When the	259	The block will be called for every message received on the port, with the
319	callback returns a true value its job is considered "done" and the port	260	global variable C<$SELF> set to the port ID. Runtime errors will cause the
320	will be destroyed. Otherwise it will stay alive.	261	port to be C<kil>ed. The message will be passed as-is, no extra argument
		262	(i.e. no port ID) will be passed to the callback.
321		263
322	The message will be passed as-is, no extra argument (i.e. no port id) will	264	If you want to stop/destroy the port, simply C<kil> it:
323	be passed to the callback.
324		265
325	If you need the local port id in the callback, this works nicely:	266	my $port = port {
326		267	my @msg = @_;
327	my $port; $port = port {	268	...
328	snd $otherport, reply => $port;	269	kil $SELF;
329	};	270	};
330		271
331	=cut	272	=cut
332		273
333	sub rcv($@);	274	sub rcv($@);
		275
		276	sub _kilme {
		277	die "received message on port without callback";
		278	}
334		279
335	sub port(;&) {	280	sub port(;&) {
336	my $id = "$UNIQ." . $ID++;	281	my $id = "$UNIQ." . $ID++;
337	my $port = "$NODE#$id";	282	my $port = "$NODE#$id";
338		283
339	if (@_) {	284	rcv $port, shift \|\| \&_kilme;
340	rcv $port, shift;
341	} else {
342	$PORT{$id} = sub { }; # nop
343	}
344		285
345	$port	286	$port
346	}	287	}
347		288
348	=item reg $port, $name
349
350	=item reg $name
351
352	Registers the given port (or C<$SELF><<< if missing) under the name
353	C<$name>. If the name already exists it is replaced.
354
355	A port can only be registered under one well known name.
356
357	A port automatically becomes unregistered when it is killed.
358
359	=cut
360
361	sub reg(@) {
362	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
363
364	$REG{$_[0]} = $port;
365	}
366
367	=item rcv $port, $callback->(@msg)	289	=item rcv $local_port, $callback->(@msg)
368		290
369	Replaces the callback on the specified miniport (after converting it to	291	Replaces the default callback on the specified port. There is no way to
370	one if required).	292	remove the default callback: use C<sub { }> to disable it, or better
371		293	C<kil> the port when it is no longer needed.
372	=item rcv $port, tagstring => $callback->(@msg), ...
373
374	=item rcv $port, $smartmatch => $callback->(@msg), ...
375
376	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
377
378	Register callbacks to be called on matching messages on the given full
379	port (after converting it to one if required) and return the port.
380
381	The callback has to return a true value when its work is done, after
382	which is will be removed, or a false value in which case it will stay
383	registered.
384		294
385	The global C<$SELF> (exported by this module) contains C<$port> while	295	The global C<$SELF> (exported by this module) contains C<$port> while
386	executing the callback.	296	executing the callback. Runtime errors during callback execution will
		297	result in the port being C<kil>ed.
387		298
388	Runtime errors during callback execution will result in the port being	299	The default callback received all messages not matched by a more specific
389	C<kil>ed.	300	C<tag> match.
390		301
391	If the match is an array reference, then it will be matched against the	302	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
392	first elements of the message, otherwise only the first element is being
393	matched.
394		303
395	Any element in the match that is specified as C<_any_> (a function	304	Register (or replace) callbacks to be called on messages starting with the
396	exported by this module) matches any single element of the message.	305	given tag on the given port (and return the port), or unregister it (when
		306	C<$callback> is C<$undef> or missing). There can only be one callback
		307	registered for each tag.
397		308
398	While not required, it is highly recommended that the first matching	309	The original message will be passed to the callback, after the first
399	element is a string identifying the message. The one-string-only match is	310	element (the tag) has been removed. The callback will use the same
400	also the most efficient match (by far).	311	environment as the default callback (see above).
401		312
402	Example: create a port and bind receivers on it in one go.	313	Example: create a port and bind receivers on it in one go.
403		314
404	my $port = rcv port,	315	my $port = rcv port,
405	msg1 => sub { ...; 0 },	316	msg1 => sub { ... },
406	msg2 => sub { ...; 0 },	317	msg2 => sub { ... },
407	;	318	;
408		319
409	Example: create a port, bind receivers and send it in a message elsewhere	320	Example: create a port, bind receivers and send it in a message elsewhere
410	in one go:	321	in one go:
411		322
412	snd $otherport, reply =>	323	snd $otherport, reply =>
413	rcv port,	324	rcv port,
414	msg1 => sub { ...; 0 },	325	msg1 => sub { ... },
415	...	326	...
416	;	327	;
		328
		329	Example: temporarily register a rcv callback for a tag matching some port
		330	(e.g. for a rpc reply) and unregister it after a message was received.
		331
		332	rcv $port, $otherport => sub {
		333	my @reply = @_;
		334
		335	rcv $SELF, $otherport;
		336	};
417		337
418	=cut	338	=cut
419		339
420	sub rcv($@) {	340	sub rcv($@) {
421	my $port = shift;	341	my $port = shift;
422	my ($noderef, $portid) = split /#/, $port, 2;	342	my ($noderef, $portid) = split /#/, $port, 2;
423		343
424	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	344	$NODE{$noderef} == $NODE{""}
425	or Carp::croak "$port: rcv can only be called on local ports, caught";	345	or Carp::croak "$port: rcv can only be called on local ports, caught";
426		346
427	if (@_ == 1) {	347	while (@_) {
		348	if (ref $_[0]) {
		349	if (my $self = $PORT_DATA{$portid}) {
		350	"AnyEvent::MP::Port" eq ref $self
		351	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		352
		353	$self->[2] = shift;
		354	} else {
428	my $cb = shift;	355	my $cb = shift;
429	delete $PORT_DATA{$portid};
430	$PORT{$portid} = sub {	356	$PORT{$portid} = sub {
431	local $SELF = $port;	357	local $SELF = $port;
432	eval {	358	eval { &$cb }; _self_die if $@;
433	&$cb	359	};
434	and kil $port;
435	};	360	}
436	_self_die if $@;	361	} elsif (defined $_[0]) {
437	};
438	} else {
439	my $self = $PORT_DATA{$portid} \|\|= do {	362	my $self = $PORT_DATA{$portid} \|\|= do {
440	my $self = bless {	363	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
441	id => $port,
442	}, "AnyEvent::MP::Port";
443		364
444	$PORT{$portid} = sub {	365	$PORT{$portid} = sub {
445	local $SELF = $port;	366	local $SELF = $port;
446		367
447	eval {
448	for (@{ $self->{rc0}{$_[0]} }) {	368	if (my $cb = $self->[1]{$_[0]}) {
449	$_ && &{$_->[0]}	369	shift;
450	&& undef $_;	370	eval { &$cb }; _self_die if $@;
451	}	371	} else {
452
453	for (@{ $self->{rcv}{$_[0]} }) {
454	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
455	&& &{$_->[0]}	372	&{ $self->[0] };
456	&& undef $_;
457	}
458
459	for (@{ $self->{any} }) {
460	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
461	&& &{$_->[0]}
462	&& undef $_;
463	}	373	}
464	};	374	};
465	_self_die if $@;	375
		376	$self
466	};	377	};
467		378
468	$self
469	};
470
471	"AnyEvent::MP::Port" eq ref $self	379	"AnyEvent::MP::Port" eq ref $self
472	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	380	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
473		381
474	while (@_) {
475	my ($match, $cb) = splice @_, 0, 2;	382	my ($tag, $cb) = splice @_, 0, 2;
476		383
477	if (!ref $match) {	384	if (defined $cb) {
478	push @{ $self->{rc0}{$match} }, [$cb];	385	$self->[1]{$tag} = $cb;
479	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
480	my ($type, @match) = @$match;
481	@match
482	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
483	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
484	} else {	386	} else {
485	push @{ $self->{any} }, [$cb, $match];	387	delete $self->[1]{$tag};
486	}	388	}
487	}	389	}
488	}	390	}
489		391
490	$port	392	$port
…		…
545	will arrive, or the monitoring action will be invoked after possible	447	will arrive, or the monitoring action will be invoked after possible
546	message loss has been detected. No messages will be lost "in between"	448	message loss has been detected. No messages will be lost "in between"
547	(after the first lost message no further messages will be received by the	449	(after the first lost message no further messages will be received by the
548	port). After the monitoring action was invoked, further messages might get	450	port). After the monitoring action was invoked, further messages might get
549	delivered again.	451	delivered again.
		452
		453	Note that monitoring-actions are one-shot: once released, they are removed
		454	and will not trigger again.
550		455
551	In the first form (callback), the callback is simply called with any	456	In the first form (callback), the callback is simply called with any
552	number of C<@reason> elements (no @reason means that the port was deleted	457	number of C<@reason> elements (no @reason means that the port was deleted
553	"normally"). Note also that I<< the callback B<must> never die >>, so use	458	"normally"). Note also that I<< the callback B<must> never die >>, so use
554	C<eval> if unsure.	459	C<eval> if unsure.
…		…
715	my $id = "$RUNIQ." . $ID++;	620	my $id = "$RUNIQ." . $ID++;
716		621
717	$_[0] =~ /::/	622	$_[0] =~ /::/
718	or Carp::croak "spawn init function must be a fully-qualified name, caught";	623	or Carp::croak "spawn init function must be a fully-qualified name, caught";
719		624
720	($NODE{$noderef} \|\| add_node $noderef)	625	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
721	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
722		626
723	"$noderef#$id"	627	"$noderef#$id"
724	}	628	}
725		629
726	=back	630	=item after $timeout, @msg
727		631
728	=head1 NODE MESSAGES	632	=item after $timeout, $callback
729		633
730	Nodes understand the following messages sent to them. Many of them take	634	Either sends the given message, or call the given callback, after the
731	arguments called C<@reply>, which will simply be used to compose a reply	635	specified number of seconds.
732	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
733	the remaining arguments are simply the message data.
734		636
735	While other messages exist, they are not public and subject to change.	637	This is simply a utility function that come sin handy at times.
736		638
737	=over 4
738
739	=cut	639	=cut
740		640
741	=item lookup => $name, @reply	641	sub after($@) {
		642	my ($timeout, @action) = @_;
742		643
743	Replies with the port ID of the specified well-known port, or C<undef>.	644	my $t; $t = AE::timer $timeout, 0, sub {
744		645	undef $t;
745	=item devnull => ...	646	ref $action[0]
746		647	? $action[0]()
747	Generic data sink/CPU heat conversion.	648	: snd @action;
748		649	};
749	=item relay => $port, @msg	650	}
750
751	Simply forwards the message to the given port.
752
753	=item eval => $string[ @reply]
754
755	Evaluates the given string. If C<@reply> is given, then a message of the
756	form C<@reply, $@, @evalres> is sent.
757
758	Example: crash another node.
759
760	snd $othernode, eval => "exit";
761
762	=item time => @reply
763
764	Replies the the current node time to C<@reply>.
765
766	Example: tell the current node to send the current time to C<$myport> in a
767	C<timereply> message.
768
769	snd $NODE, time => $myport, timereply => 1, 2;
770	# => snd $myport, timereply => 1, 2, <time>
771		651
772	=back	652	=back
773		653
774	=head1 AnyEvent::MP vs. Distributed Erlang	654	=head1 AnyEvent::MP vs. Distributed Erlang
775		655
…		…
785		665
786	Despite the similarities, there are also some important differences:	666	Despite the similarities, there are also some important differences:
787		667
788	=over 4	668	=over 4
789		669
790	=item * Node references contain the recipe on how to contact them.	670	=item * Node IDs are arbitrary strings in AEMP.
791		671
792	Erlang relies on special naming and DNS to work everywhere in the	672	Erlang relies on special naming and DNS to work everywhere in the same
793	same way. AEMP relies on each node knowing it's own address(es), with	673	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
794	convenience functionality.	674	configuraiton or DNS), but will otherwise discover other odes itself.
795		675
796	This means that AEMP requires a less tightly controlled environment at the	676	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
797	cost of longer node references and a slightly higher management overhead.	677	uses "local ports are like remote ports".
		678
		679	The failure modes for local ports are quite different (runtime errors
		680	only) then for remote ports - when a local port dies, you I<know> it dies,
		681	when a connection to another node dies, you know nothing about the other
		682	port.
		683
		684	Erlang pretends remote ports are as reliable as local ports, even when
		685	they are not.
		686
		687	AEMP encourages a "treat remote ports differently" philosophy, with local
		688	ports being the special case/exception, where transport errors cannot
		689	occur.
798		690
799	=item * Erlang uses processes and a mailbox, AEMP does not queue.	691	=item * Erlang uses processes and a mailbox, AEMP does not queue.
800		692
801	Erlang uses processes that selctively receive messages, and therefore	693	Erlang uses processes that selectively receive messages, and therefore
802	needs a queue. AEMP is event based, queuing messages would serve no useful	694	needs a queue. AEMP is event based, queuing messages would serve no
803	purpose.	695	useful purpose. For the same reason the pattern-matching abilities of
		696	AnyEvent::MP are more limited, as there is little need to be able to
		697	filter messages without dequeing them.
804		698
805	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	699	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
806		700
807	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	701	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
808		702
809	Sending messages in Erlang is synchronous and blocks the process. AEMP	703	Sending messages in Erlang is synchronous and blocks the process (and
810	sends are immediate, connection establishment is handled in the	704	so does not need a queue that can overflow). AEMP sends are immediate,
811	background.	705	connection establishment is handled in the background.
812		706
813	=item * Erlang can silently lose messages, AEMP cannot.	707	=item * Erlang suffers from silent message loss, AEMP does not.
814		708
815	Erlang makes few guarantees on messages delivery - messages can get lost	709	Erlang makes few guarantees on messages delivery - messages can get lost
816	without any of the processes realising it (i.e. you send messages a, b,	710	without any of the processes realising it (i.e. you send messages a, b,
817	and c, and the other side only receives messages a and c).	711	and c, and the other side only receives messages a and c).
818		712
819	AEMP guarantees correct ordering, and the guarantee that there are no	713	AEMP guarantees correct ordering, and the guarantee that after one message
820	holes in the message sequence.	714	is lost, all following ones sent to the same port are lost as well, until
821		715	monitoring raises an error, so there are no silent "holes" in the message
822	=item * In Erlang, processes can be declared dead and later be found to be	716	sequence.
823	alive.
824
825	In Erlang it can happen that a monitored process is declared dead and
826	linked processes get killed, but later it turns out that the process is
827	still alive - and can receive messages.
828
829	In AEMP, when port monitoring detects a port as dead, then that port will
830	eventually be killed - it cannot happen that a node detects a port as dead
831	and then later sends messages to it, finding it is still alive.
832		717
833	=item * Erlang can send messages to the wrong port, AEMP does not.	718	=item * Erlang can send messages to the wrong port, AEMP does not.
834		719
835	In Erlang it is quite possible that a node that restarts reuses a process	720	In Erlang it is quite likely that a node that restarts reuses a process ID
836	ID known to other nodes for a completely different process, causing	721	known to other nodes for a completely different process, causing messages
837	messages destined for that process to end up in an unrelated process.	722	destined for that process to end up in an unrelated process.
838		723
839	AEMP never reuses port IDs, so old messages or old port IDs floating	724	AEMP never reuses port IDs, so old messages or old port IDs floating
840	around in the network will not be sent to an unrelated port.	725	around in the network will not be sent to an unrelated port.
841		726
842	=item * Erlang uses unprotected connections, AEMP uses secure	727	=item * Erlang uses unprotected connections, AEMP uses secure
843	authentication and can use TLS.	728	authentication and can use TLS.
844		729
845	AEMP can use a proven protocol - SSL/TLS - to protect connections and	730	AEMP can use a proven protocol - TLS - to protect connections and
846	securely authenticate nodes.	731	securely authenticate nodes.
847		732
848	=item * The AEMP protocol is optimised for both text-based and binary	733	=item * The AEMP protocol is optimised for both text-based and binary
849	communications.	734	communications.
850		735
851	The AEMP protocol, unlike the Erlang protocol, supports both	736	The AEMP protocol, unlike the Erlang protocol, supports both programming
852	language-independent text-only protocols (good for debugging) and binary,	737	language independent text-only protocols (good for debugging) and binary,
853	language-specific serialisers (e.g. Storable).	738	language-specific serialisers (e.g. Storable).
854		739
855	It has also been carefully designed to be implementable in other languages	740	It has also been carefully designed to be implementable in other languages
856	with a minimum of work while gracefully degrading fucntionality to make the	741	with a minimum of work while gracefully degrading functionality to make the
857	protocol simple.	742	protocol simple.
858		743
859	=item * AEMP has more flexible monitoring options than Erlang.	744	=item * AEMP has more flexible monitoring options than Erlang.
860		745
861	In Erlang, you can chose to receive I<all> exit signals as messages	746	In Erlang, you can chose to receive I<all> exit signals as messages

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs. Revision 1.66 by root, Fri Aug 28 01:07:24 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.66 by root, Fri Aug 28 01:07:24 2009 UTC