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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.22 by root, Tue Aug 4 18:33:30 2009 UTC vs.
Revision 1.33 by root, Wed Aug 5 22:40:51 2009 UTC

…		…
30	This module (-family) implements a simple message passing framework.	30	This module (-family) implements a simple message passing framework.
31		31
32	Despite its simplicity, you can securely message other processes running	32	Despite its simplicity, you can securely message other processes running
33	on the same or other hosts.	33	on the same or other hosts.
34		34
		35	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		36	manual page.
		37
35	At the moment, this module family is severly brokena nd underdocumented,	38	At the moment, this module family is severly broken and underdocumented,
36	so do not use. This was uploaded mainly to reserve the CPAN namespace -	39	so do not use. This was uploaded mainly to reserve the CPAN namespace -
37	stay tuned!	40	stay tuned! The basic API should be finished, however.
38		41
39	=head1 CONCEPTS	42	=head1 CONCEPTS
40		43
41	=over 4	44	=over 4
42		45
43	=item port	46	=item port
44		47
45	A port is something you can send messages to with the C<snd> function, and	48	A port is something you can send messages to (with the C<snd> function).
46	you can register C<rcv> handlers with. All C<rcv> handlers will receive	49
47	messages they match, messages will not be queued.	50	Some ports allow you to register C<rcv> handlers that can match specific
		51	messages. All C<rcv> handlers will receive messages they match, messages
		52	will not be queued.
48		53
49	=item port id - C<noderef#portname>	54	=item port id - C<noderef#portname>
50		55
51	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	56	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as
52	by a port name (a printable string of unspecified format).	57	separator, and a port name (a printable string of unspecified format). An
		58	exception is the the node port, whose ID is identical to its node
		59	reference.
53		60
54	=item node	61	=item node
55		62
56	A node is a single process containing at least one port - the node	63	A node is a single process containing at least one port - the node
57	port. You can send messages to node ports to let them create new ports,	64	port. You can send messages to node ports to find existing ports or to
58	among other things.	65	create new ports, among other things.
59		66
60	Initially, nodes are either private (single-process only) or hidden	67	Nodes are either private (single-process only), slaves (connected to a
61	(connected to a master node only). Only when they epxlicitly "become	68	master node only) or public nodes (connectable from unrelated nodes).
62	public" can you send them messages from unrelated other nodes.
63		69
64	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	70	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
65		71
66	A noderef is a string that either uniquely identifies a given node (for	72	A node reference is a string that either simply identifies the node (for
67	private and hidden nodes), or contains a recipe on how to reach a given	73	private and slave nodes), or contains a recipe on how to reach a given
68	node (for public nodes).	74	node (for public nodes).
69		75
		76	This recipe is simply a comma-separated list of C<address:port> pairs (for
		77	TCP/IP, other protocols might look different).
		78
		79	Node references come in two flavours: resolved (containing only numerical
		80	addresses) or unresolved (where hostnames are used instead of addresses).
		81
		82	Before using an unresolved node reference in a message you first have to
		83	resolve it.
		84
70	=back	85	=back
71		86
72	=head1 VARIABLES/FUNCTIONS	87	=head1 VARIABLES/FUNCTIONS
73		88
74	=over 4	89	=over 4
…		…
85		100
86	use AE ();	101	use AE ();
87		102
88	use base "Exporter";	103	use base "Exporter";
89		104
90	our $VERSION = '0.02';	105	our $VERSION = '0.1';
91	our @EXPORT = qw(	106	our @EXPORT = qw(
92	NODE $NODE *SELF node_of _any_	107	NODE $NODE *SELF node_of _any_
93	become_slave become_public	108	resolve_node initialise_node
94	snd rcv mon kil reg psub	109	snd rcv mon kil reg psub
95	port	110	port
96	);	111	);
97		112
98	our $SELF;	113	our $SELF;
…		…
108	The C<NODE> function returns, and the C<$NODE> variable contains	123	The C<NODE> function returns, and the C<$NODE> variable contains
109	the noderef of the local node. The value is initialised by a call	124	the noderef of the local node. The value is initialised by a call
110	to C<become_public> or C<become_slave>, after which all local port	125	to C<become_public> or C<become_slave>, after which all local port
111	identifiers become invalid.	126	identifiers become invalid.
112		127
113	=item $noderef = node_of $portid	128	=item $noderef = node_of $port
114		129
115	Extracts and returns the noderef from a portid or a noderef.	130	Extracts and returns the noderef from a portid or a noderef.
		131
		132	=item $cv = resolve_node $noderef
		133
		134	Takes an unresolved node reference that may contain hostnames and
		135	abbreviated IDs, resolves all of them and returns a resolved node
		136	reference.
		137
		138	In addition to C<address:port> pairs allowed in resolved noderefs, the
		139	following forms are supported:
		140
		141	=over 4
		142
		143	=item the empty string
		144
		145	An empty-string component gets resolved as if the default port (4040) was
		146	specified.
		147
		148	=item naked port numbers (e.g. C<1234>)
		149
		150	These are resolved by prepending the local nodename and a colon, to be
		151	further resolved.
		152
		153	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		154
		155	These are resolved by using AnyEvent::DNS to resolve them, optionally
		156	looking up SRV records for the C<aemp=4040> port, if no port was
		157	specified.
		158
		159	=back
116		160
117	=item $SELF	161	=item $SELF
118		162
119	Contains the current port id while executing C<rcv> callbacks or C<psub>	163	Contains the current port id while executing C<rcv> callbacks or C<psub>
120	blocks.	164	blocks.
…		…
123		167
124	Due to some quirks in how perl exports variables, it is impossible to	168	Due to some quirks in how perl exports variables, it is impossible to
125	just export C<$SELF>, all the symbols called C<SELF> are exported by this	169	just export C<$SELF>, all the symbols called C<SELF> are exported by this
126	module, but only C<$SELF> is currently used.	170	module, but only C<$SELF> is currently used.
127		171
128	=item snd $portid, type => @data	172	=item snd $port, type => @data
129		173
130	=item snd $portid, @msg	174	=item snd $port, @msg
131		175
132	Send the given message to the given port ID, which can identify either	176	Send the given message to the given port ID, which can identify either
133	a local or a remote port, and can be either a string or soemthignt hat	177	a local or a remote port, and can be either a string or soemthignt hat
134	stringifies a sa port ID (such as a port object :).	178	stringifies a sa port ID (such as a port object :).
135		179
…		…
145	JSON is used, then only strings, numbers and arrays and hashes consisting	189	JSON is used, then only strings, numbers and arrays and hashes consisting
146	of those are allowed (no objects). When Storable is used, then anything	190	of those are allowed (no objects). When Storable is used, then anything
147	that Storable can serialise and deserialise is allowed, and for the local	191	that Storable can serialise and deserialise is allowed, and for the local
148	node, anything can be passed.	192	node, anything can be passed.
149		193
150	=item kil $portid[, @reason]
151
152	Kill the specified port with the given C<@reason>.
153
154	If no C<@reason> is specified, then the port is killed "normally" (linked
155	ports will not be kileld, or even notified).
156
157	Otherwise, linked ports get killed with the same reason (second form of
158	C<mon>, see below).
159
160	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
161	will be reported as reason C<< die => $@ >>.
162
163	Transport/communication errors are reported as C<< transport_error =>
164	$message >>.
165
166	=item $guard = mon $portid, $cb->(@reason)
167
168	=item $guard = mon $portid, $otherport
169
170	=item $guard = mon $portid, $otherport, @msg
171
172	Monitor the given port and do something when the port is killed.
173
174	In the first form, the callback is simply called with any number
175	of C<@reason> elements (no @reason means that the port was deleted
176	"normally"). Note also that I<< the callback B<must> never die >>, so use
177	C<eval> if unsure.
178
179	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
180	a @reason was specified, i.e. on "normal" kils nothing happens, while
181	under all other conditions, the other port is killed with the same reason.
182
183	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
184
185	Example: call a given callback when C<$port> is killed.
186
187	mon $port, sub { warn "port died because of <@_>\n" };
188
189	Example: kill ourselves when C<$port> is killed abnormally.
190
191	mon $port, $self;
192
193	Example: send us a restart message another C<$port> is killed.
194
195	mon $port, $self => "restart";
196
197	=cut
198
199	sub mon {
200	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
201
202	my $node = $NODE{$noderef} \|\| add_node $noderef;
203
204	#TODO: ports must not be references
205	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
206	if (@_) {
207	# send a kill info message
208	my (@msg) = ($cb, @_);
209	$cb = sub { snd @msg, @_ };
210	} else {
211	# simply kill other port
212	my $port = $cb;
213	$cb = sub { kil $port, @_ if @_ };
214	}
215	}
216
217	$node->monitor ($port, $cb);
218
219	defined wantarray
220	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
221	}
222
223	=item $guard = mon_guard $port, $ref, $ref...
224
225	Monitors the given C<$port> and keeps the passed references. When the port
226	is killed, the references will be freed.
227
228	Optionally returns a guard that will stop the monitoring.
229
230	This function is useful when you create e.g. timers or other watchers and
231	want to free them when the port gets killed:
232
233	$port->rcv (start => sub {
234	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
235	undef $timer if 0.9 < rand;
236	});
237	});
238
239	=cut
240
241	sub mon_guard {
242	my ($port, @refs) = @_;
243
244	mon $port, sub { 0 && @refs }
245	}
246
247	=item $local_port = port	194	=item $local_port = port
248		195
249	Create a new local port object that supports message matching.	196	Create a new local port object that can be used either as a pattern
		197	matching port ("full port") or a single-callback port ("miniport"),
		198	depending on how C<rcv> callbacks are bound to the object.
250		199
251	=item $portid = port { my @msg = @_; $finished }	200	=item $port = port { my @msg = @_; $finished }
252		201
253	Creates a "mini port", that is, a very lightweight port without any	202	Creates a "miniport", that is, a very lightweight port without any pattern
254	pattern matching behind it, and returns its ID.	203	matching behind it, and returns its ID. Semantically the same as creating
		204	a port and calling C<rcv $port, $callback> on it.
255		205
256	The block will be called for every message received on the port. When the	206	The block will be called for every message received on the port. When the
257	callback returns a true value its job is considered "done" and the port	207	callback returns a true value its job is considered "done" and the port
258	will be destroyed. Otherwise it will stay alive.	208	will be destroyed. Otherwise it will stay alive.
259		209
260	The message will be passed as-is, no extra argument (i.e. no port id) will	210	The message will be passed as-is, no extra argument (i.e. no port id) will
261	be passed to the callback.	211	be passed to the callback.
262		212
263	If you need the local port id in the callback, this works nicely:	213	If you need the local port id in the callback, this works nicely:
264		214
265	my $port; $port = miniport {	215	my $port; $port = port {
266	snd $otherport, reply => $port;	216	snd $otherport, reply => $port;
267	};	217	};
268		218
269	=cut	219	=cut
		220
		221	sub rcv($@);
270		222
271	sub port(;&) {	223	sub port(;&) {
272	my $id = "$UNIQ." . $ID++;	224	my $id = "$UNIQ." . $ID++;
273	my $port = "$NODE#$id";	225	my $port = "$NODE#$id";
274		226
275	if (@_) {	227	if (@_) {
		228	rcv $port, shift;
		229	} else {
		230	$PORT{$id} = sub { }; # nop
		231	}
		232
		233	$port
		234	}
		235
		236	=item reg $port, $name
		237
		238	Registers the given port under the name C<$name>. If the name already
		239	exists it is replaced.
		240
		241	A port can only be registered under one well known name.
		242
		243	A port automatically becomes unregistered when it is killed.
		244
		245	=cut
		246
		247	sub reg(@) {
		248	my ($port, $name) = @_;
		249
		250	$REG{$name} = $port;
		251	}
		252
		253	=item rcv $port, $callback->(@msg)
		254
		255	Replaces the callback on the specified miniport (after converting it to
		256	one if required).
		257
		258	=item rcv $port, tagstring => $callback->(@msg), ...
		259
		260	=item rcv $port, $smartmatch => $callback->(@msg), ...
		261
		262	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		263
		264	Register callbacks to be called on matching messages on the given full
		265	port (after converting it to one if required).
		266
		267	The callback has to return a true value when its work is done, after
		268	which is will be removed, or a false value in which case it will stay
		269	registered.
		270
		271	The global C<$SELF> (exported by this module) contains C<$port> while
		272	executing the callback.
		273
		274	Runtime errors wdurign callback execution will result in the port being
		275	C<kil>ed.
		276
		277	If the match is an array reference, then it will be matched against the
		278	first elements of the message, otherwise only the first element is being
		279	matched.
		280
		281	Any element in the match that is specified as C<_any_> (a function
		282	exported by this module) matches any single element of the message.
		283
		284	While not required, it is highly recommended that the first matching
		285	element is a string identifying the message. The one-string-only match is
		286	also the most efficient match (by far).
		287
		288	=cut
		289
		290	sub rcv($@) {
		291	my $port = shift;
		292	my ($noderef, $portid) = split /#/, $port, 2;
		293
		294	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		295	or Carp::croak "$port: rcv can only be called on local ports, caught";
		296
		297	if (@_ == 1) {
276	my $cb = shift;	298	my $cb = shift;
		299	delete $PORT_DATA{$portid};
277	$PORT{$id} = sub {	300	$PORT{$portid} = sub {
278	local $SELF = $port;	301	local $SELF = $port;
279	eval {	302	eval {
280	&$cb	303	&$cb
281	and kil $id;	304	and kil $port;
282	};	305	};
283	_self_die if $@;	306	_self_die if $@;
284	};	307	};
285	} else {	308	} else {
		309	my $self = $PORT_DATA{$portid} \|\|= do {
286	my $self = bless {	310	my $self = bless {
287	id => "$NODE#$id",	311	id => $port,
288	}, "AnyEvent::MP::Port";	312	}, "AnyEvent::MP::Port";
289		313
290	$PORT_DATA{$id} = $self;
291	$PORT{$id} = sub {	314	$PORT{$portid} = sub {
292	local $SELF = $port;	315	local $SELF = $port;
293		316
294	eval {	317	eval {
295	for (@{ $self->{rc0}{$_[0]} }) {	318	for (@{ $self->{rc0}{$_[0]} }) {
296	$_ && &{$_->[0]}	319	$_ && &{$_->[0]}
297	&& undef $_;	320	&& undef $_;
298	}	321	}
299		322
300	for (@{ $self->{rcv}{$_[0]} }) {	323	for (@{ $self->{rcv}{$_[0]} }) {
301	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	324	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
302	&& &{$_->[0]}	325	&& &{$_->[0]}
303	&& undef $_;	326	&& undef $_;
304	}	327	}
305		328
306	for (@{ $self->{any} }) {	329	for (@{ $self->{any} }) {
307	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	330	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
308	&& &{$_->[0]}	331	&& &{$_->[0]}
309	&& undef $_;	332	&& undef $_;
		333	}
310	}	334	};
		335	_self_die if $@;
311	};	336	};
312	_self_die if $@;	337
		338	$self
313	};	339	};
314	}
315		340
316	$port
317	}
318
319	=item reg $portid, $name
320
321	Registers the given port under the name C<$name>. If the name already
322	exists it is replaced.
323
324	A port can only be registered under one well known name.
325
326	A port automatically becomes unregistered when it is killed.
327
328	=cut
329
330	sub reg(@) {
331	my ($portid, $name) = @_;
332
333	$REG{$name} = $portid;
334	}
335
336	=item rcv $portid, tagstring => $callback->(@msg), ...
337
338	=item rcv $portid, $smartmatch => $callback->(@msg), ...
339
340	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
341
342	Register callbacks to be called on matching messages on the given port.
343
344	The callback has to return a true value when its work is done, after
345	which is will be removed, or a false value in which case it will stay
346	registered.
347
348	The global C<$SELF> (exported by this module) contains C<$portid> while
349	executing the callback.
350
351	Runtime errors wdurign callback execution will result in the port being
352	C<kil>ed.
353
354	If the match is an array reference, then it will be matched against the
355	first elements of the message, otherwise only the first element is being
356	matched.
357
358	Any element in the match that is specified as C<_any_> (a function
359	exported by this module) matches any single element of the message.
360
361	While not required, it is highly recommended that the first matching
362	element is a string identifying the message. The one-string-only match is
363	also the most efficient match (by far).
364
365	=cut
366
367	sub rcv($@) {
368	my ($noderef, $port) = split /#/, shift, 2;
369
370	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
371	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
372
373	my $self = $PORT_DATA{$port}
374	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
375
376	"AnyEvent::MP::Port" eq ref $self	341	"AnyEvent::MP::Port" eq ref $self
377	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";	342	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
378		343
379	while (@_) {	344	while (@_) {
380	my ($match, $cb) = splice @_, 0, 2;	345	my ($match, $cb) = splice @_, 0, 2;
381		346
382	if (!ref $match) {	347	if (!ref $match) {
383	push @{ $self->{rc0}{$match} }, [$cb];	348	push @{ $self->{rc0}{$match} }, [$cb];
384	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	349	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
385	my ($type, @match) = @$match;	350	my ($type, @match) = @$match;
386	@match	351	@match
387	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	352	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
388	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	353	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
389	} else {	354	} else {
390	push @{ $self->{any} }, [$cb, $match];	355	push @{ $self->{any} }, [$cb, $match];
		356	}
391	}	357	}
392	}	358	}
		359
		360	$port
393	}	361	}
394		362
395	=item $closure = psub { BLOCK }	363	=item $closure = psub { BLOCK }
396		364
397	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	365	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
…		…
428	$res	396	$res
429	}	397	}
430	}	398	}
431	}	399	}
432		400
		401	=item $guard = mon $port, $cb->(@reason)
		402
		403	=item $guard = mon $port, $otherport
		404
		405	=item $guard = mon $port, $otherport, @msg
		406
		407	Monitor the given port and do something when the port is killed.
		408
		409	In the first form, the callback is simply called with any number
		410	of C<@reason> elements (no @reason means that the port was deleted
		411	"normally"). Note also that I<< the callback B<must> never die >>, so use
		412	C<eval> if unsure.
		413
		414	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
		415	a @reason was specified, i.e. on "normal" kils nothing happens, while
		416	under all other conditions, the other port is killed with the same reason.
		417
		418	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
		419
		420	Example: call a given callback when C<$port> is killed.
		421
		422	mon $port, sub { warn "port died because of <@_>\n" };
		423
		424	Example: kill ourselves when C<$port> is killed abnormally.
		425
		426	mon $port, $self;
		427
		428	Example: send us a restart message another C<$port> is killed.
		429
		430	mon $port, $self => "restart";
		431
		432	=cut
		433
		434	sub mon {
		435	my ($noderef, $port) = split /#/, shift, 2;
		436
		437	my $node = $NODE{$noderef} \|\| add_node $noderef;
		438
		439	my $cb = shift;
		440
		441	unless (ref $cb) {
		442	if (@_) {
		443	# send a kill info message
		444	my (@msg) = ($cb, @_);
		445	$cb = sub { snd @msg, @_ };
		446	} else {
		447	# simply kill other port
		448	my $port = $cb;
		449	$cb = sub { kil $port, @_ if @_ };
		450	}
		451	}
		452
		453	$node->monitor ($port, $cb);
		454
		455	defined wantarray
		456	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		457	}
		458
		459	=item $guard = mon_guard $port, $ref, $ref...
		460
		461	Monitors the given C<$port> and keeps the passed references. When the port
		462	is killed, the references will be freed.
		463
		464	Optionally returns a guard that will stop the monitoring.
		465
		466	This function is useful when you create e.g. timers or other watchers and
		467	want to free them when the port gets killed:
		468
		469	$port->rcv (start => sub {
		470	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		471	undef $timer if 0.9 < rand;
		472	});
		473	});
		474
		475	=cut
		476
		477	sub mon_guard {
		478	my ($port, @refs) = @_;
		479
		480	mon $port, sub { 0 && @refs }
		481	}
		482
		483	=item lnk $port1, $port2
		484
		485	Link two ports. This is simply a shorthand for:
		486
		487	mon $port1, $port2;
		488	mon $port2, $port1;
		489
		490	It means that if either one is killed abnormally, the other one gets
		491	killed as well.
		492
		493	=item kil $port[, @reason]
		494
		495	Kill the specified port with the given C<@reason>.
		496
		497	If no C<@reason> is specified, then the port is killed "normally" (linked
		498	ports will not be kileld, or even notified).
		499
		500	Otherwise, linked ports get killed with the same reason (second form of
		501	C<mon>, see below).
		502
		503	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		504	will be reported as reason C<< die => $@ >>.
		505
		506	Transport/communication errors are reported as C<< transport_error =>
		507	$message >>.
		508
433	=back	509	=back
434		510
435	=head1 FUNCTIONS FOR NODES	511	=head1 FUNCTIONS FOR NODES
436		512
437	=over 4	513	=over 4
438		514
439	=item become_public endpoint...	515	=item initialise_node $noderef, $seednode, $seednode...
440		516
441	Tells the node to become a public node, i.e. reachable from other nodes.	517	=item initialise_node "slave/", $master, $master...
442		518
443	If no arguments are given, or the first argument is C<undef>, then	519	Initialises a node - must be called exactly once before calling other
444	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	520	AnyEvent::MP functions when talking to other nodes is required.
445	local nodename resolves to.
446		521
447	Otherwise the first argument must be an array-reference with transport	522	All arguments are noderefs, which can be either resolved or unresolved.
448	endpoints ("ip:port", "hostname:port") or port numbers (in which case the	523
449	local nodename is used as hostname). The endpoints are all resolved and	524	There are two types of networked nodes, public nodes and slave nodes:
450	will become the node reference.	525
		526	=over 4
		527
		528	=item public nodes
		529
		530	For public nodes, C<$noderef> must either be a (possibly unresolved)
		531	noderef, in which case it will be resolved, or C<undef> (or missing), in
		532	which case the noderef will be guessed.
		533
		534	Afterwards, the node will bind itself on all endpoints and try to connect
		535	to all additional C<$seednodes> that are specified. Seednodes are optional
		536	and can be used to quickly bootstrap the node into an existing network.
		537
		538	=item slave nodes
		539
		540	When the C<$noderef> is the special string C<slave/>, then the node will
		541	become a slave node. Slave nodes cannot be contacted from outside and will
		542	route most of their traffic to the master node that they attach to.
		543
		544	At least one additional noderef is required: The node will try to connect
		545	to all of them and will become a slave attached to the first node it can
		546	successfully connect to.
		547
		548	=back
		549
		550	This function will block until all nodes have been resolved and, for slave
		551	nodes, until it has successfully established a connection to a master
		552	server.
		553
		554	Example: become a public node listening on the default node.
		555
		556	initialise_node;
		557
		558	Example: become a public node, and try to contact some well-known master
		559	servers to become part of the network.
		560
		561	initialise_node undef, "master1", "master2";
		562
		563	Example: become a public node listening on port C<4041>.
		564
		565	initialise_node 4041;
		566
		567	Example: become a public node, only visible on localhost port 4044.
		568
		569	initialise_node "locahost:4044";
		570
		571	Example: become a slave node to any of the specified master servers.
		572
		573	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
451		574
452	=cut	575	=cut
453		576
454	=back	577	=back
455		578
…		…
458	Nodes understand the following messages sent to them. Many of them take	581	Nodes understand the following messages sent to them. Many of them take
459	arguments called C<@reply>, which will simply be used to compose a reply	582	arguments called C<@reply>, which will simply be used to compose a reply
460	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	583	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
461	the remaining arguments are simply the message data.	584	the remaining arguments are simply the message data.
462		585
		586	While other messages exist, they are not public and subject to change.
		587
463	=over 4	588	=over 4
464		589
465	=cut	590	=cut
466		591
467	=item lookup => $name, @reply	592	=item lookup => $name, @reply
…		…
495	snd $NODE, time => $myport, timereply => 1, 2;	620	snd $NODE, time => $myport, timereply => 1, 2;
496	# => snd $myport, timereply => 1, 2, <time>	621	# => snd $myport, timereply => 1, 2, <time>
497		622
498	=back	623	=back
499		624
		625	=head1 AnyEvent::MP vs. Distributed Erlang
		626
		627	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node
		628	== aemp node, erlang process == aemp port), so many of the documents and
		629	programming techniques employed by erlang apply to AnyEvent::MP. Here is a
		630	sample:
		631
		632	http://www.erlang.se/doc/programming_rules.shtml
		633	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		634	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
		635	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		636
		637	Despite the similarities, there are also some important differences:
		638
		639	=over 4
		640
		641	=item * Node references contain the recipe on how to contact them.
		642
		643	Erlang relies on special naming and DNS to work everywhere in the
		644	same way. AEMP relies on each node knowing it's own address(es), with
		645	convenience functionality.
		646
		647	This means that AEMP requires a less tightly controlled environment at the
		648	cost of longer node references and a slightly higher management overhead.
		649
		650	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		651
		652	Erlang uses processes that selctively receive messages, and therefore
		653	needs a queue. AEMP is event based, queuing messages would serve no useful
		654	purpose.
		655
		656	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		657
		658	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		659
		660	Sending messages in erlang is synchronous and blocks the process. AEMP
		661	sends are immediate, connection establishment is handled in the
		662	background.
		663
		664	=item * Erlang can silently lose messages, AEMP cannot.
		665
		666	Erlang makes few guarantees on messages delivery - messages can get lost
		667	without any of the processes realising it (i.e. you send messages a, b,
		668	and c, and the other side only receives messages a and c).
		669
		670	AEMP guarantees correct ordering, and the guarantee that there are no
		671	holes in the message sequence.
		672
		673	=item * In erlang, processes can be declared dead and later be found to be
		674	alive.
		675
		676	In erlang it can happen that a monitored process is declared dead and
		677	linked processes get killed, but later it turns out that the process is
		678	still alive - and can receive messages.
		679
		680	In AEMP, when port monitoring detects a port as dead, then that port will
		681	eventually be killed - it cannot happen that a node detects a port as dead
		682	and then later sends messages to it, finding it is still alive.
		683
		684	=item * Erlang can send messages to the wrong port, AEMP does not.
		685
		686	In erlang it is quite possible that a node that restarts reuses a process
		687	ID known to other nodes for a completely different process, causing
		688	messages destined for that process to end up in an unrelated process.
		689
		690	AEMP never reuses port IDs, so old messages or old port IDs floating
		691	around in the network will not be sent to an unrelated port.
		692
		693	=item * Erlang uses unprotected connections, AEMP uses secure
		694	authentication and can use TLS.
		695
		696	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		697	securely authenticate nodes.
		698
		699	=item * The AEMP protocol is optimised for both text-based and binary
		700	communications.
		701
		702	The AEMP protocol, unlike the erlang protocol, supports both
		703	language-independent text-only protocols (good for debugging) and binary,
		704	language-specific serialisers (e.g. Storable).
		705
		706	It has also been carefully designed to be implementable in other languages
		707	with a minimum of work while gracefully degrading fucntionality to make the
		708	protocol simple.
		709
		710	=back
		711
500	=head1 SEE ALSO	712	=head1 SEE ALSO
501		713
502	L<AnyEvent>.	714	L<AnyEvent>.
503		715
504	=head1 AUTHOR	716	=head1 AUTHOR

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Revision 1.33 by root, Wed Aug 5 22:40:51 2009 UTC