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

Comparing cvsroot/AnyEvent-MP/MP.pm (file contents):
Revision 1.23 by root, Tue Aug 4 18:46:16 2009 UTC vs.
Revision 1.33 by root, Wed Aug 5 22:40:51 2009 UTC

…		…
43		43
44	=over 4	44	=over 4
45		45
46	=item port	46	=item port
47		47
48	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).
49	you can register C<rcv> handlers with. All C<rcv> handlers will receive	49
50	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.
51		53
52	=item port id - C<noderef#portname>	54	=item port id - C<noderef#portname>
53		55
54	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
55	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.
56		60
57	=item node	61	=item node
58		62
59	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
60	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
61	among other things.	65	create new ports, among other things.
62		66
63	Initially, nodes are either private (single-process only) or hidden	67	Nodes are either private (single-process only), slaves (connected to a
64	(connected to a master node only). Only when they epxlicitly "become	68	master node only) or public nodes (connectable from unrelated nodes).
65	public" can you send them messages from unrelated other nodes.
66		69
67	=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>
68		71
69	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
70	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
71	node (for public nodes).	74	node (for public nodes).
72		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
73	=back	85	=back
74		86
75	=head1 VARIABLES/FUNCTIONS	87	=head1 VARIABLES/FUNCTIONS
76		88
77	=over 4	89	=over 4
…		…
88		100
89	use AE ();	101	use AE ();
90		102
91	use base "Exporter";	103	use base "Exporter";
92		104
93	our $VERSION = '0.02';	105	our $VERSION = '0.1';
94	our @EXPORT = qw(	106	our @EXPORT = qw(
95	NODE $NODE *SELF node_of _any_	107	NODE $NODE *SELF node_of _any_
96	become_slave become_public	108	resolve_node initialise_node
97	snd rcv mon kil reg psub	109	snd rcv mon kil reg psub
98	port	110	port
99	);	111	);
100		112
101	our $SELF;	113	our $SELF;
…		…
111	The C<NODE> function returns, and the C<$NODE> variable contains	123	The C<NODE> function returns, and the C<$NODE> variable contains
112	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
113	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
114	identifiers become invalid.	126	identifiers become invalid.
115		127
116	=item $noderef = node_of $portid	128	=item $noderef = node_of $port
117		129
118	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
119		160
120	=item $SELF	161	=item $SELF
121		162
122	Contains the current port id while executing C<rcv> callbacks or C<psub>	163	Contains the current port id while executing C<rcv> callbacks or C<psub>
123	blocks.	164	blocks.
…		…
126		167
127	Due to some quirks in how perl exports variables, it is impossible to	168	Due to some quirks in how perl exports variables, it is impossible to
128	just export C<$SELF>, all the symbols called C<SELF> are exported by this	169	just export C<$SELF>, all the symbols called C<SELF> are exported by this
129	module, but only C<$SELF> is currently used.	170	module, but only C<$SELF> is currently used.
130		171
131	=item snd $portid, type => @data	172	=item snd $port, type => @data
132		173
133	=item snd $portid, @msg	174	=item snd $port, @msg
134		175
135	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
136	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
137	stringifies a sa port ID (such as a port object :).	178	stringifies a sa port ID (such as a port object :).
138		179
…		…
148	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
149	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
150	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
151	node, anything can be passed.	192	node, anything can be passed.
152		193
153	=item kil $portid[, @reason]
154
155	Kill the specified port with the given C<@reason>.
156
157	If no C<@reason> is specified, then the port is killed "normally" (linked
158	ports will not be kileld, or even notified).
159
160	Otherwise, linked ports get killed with the same reason (second form of
161	C<mon>, see below).
162
163	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
164	will be reported as reason C<< die => $@ >>.
165
166	Transport/communication errors are reported as C<< transport_error =>
167	$message >>.
168
169	=item $guard = mon $portid, $cb->(@reason)
170
171	=item $guard = mon $portid, $otherport
172
173	=item $guard = mon $portid, $otherport, @msg
174
175	Monitor the given port and do something when the port is killed.
176
177	In the first form, the callback is simply called with any number
178	of C<@reason> elements (no @reason means that the port was deleted
179	"normally"). Note also that I<< the callback B<must> never die >>, so use
180	C<eval> if unsure.
181
182	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
183	a @reason was specified, i.e. on "normal" kils nothing happens, while
184	under all other conditions, the other port is killed with the same reason.
185
186	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
187
188	Example: call a given callback when C<$port> is killed.
189
190	mon $port, sub { warn "port died because of <@_>\n" };
191
192	Example: kill ourselves when C<$port> is killed abnormally.
193
194	mon $port, $self;
195
196	Example: send us a restart message another C<$port> is killed.
197
198	mon $port, $self => "restart";
199
200	=cut
201
202	sub mon {
203	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
204
205	my $node = $NODE{$noderef} \|\| add_node $noderef;
206
207	#TODO: ports must not be references
208	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
209	if (@_) {
210	# send a kill info message
211	my (@msg) = ($cb, @_);
212	$cb = sub { snd @msg, @_ };
213	} else {
214	# simply kill other port
215	my $port = $cb;
216	$cb = sub { kil $port, @_ if @_ };
217	}
218	}
219
220	$node->monitor ($port, $cb);
221
222	defined wantarray
223	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
224	}
225
226	=item $guard = mon_guard $port, $ref, $ref...
227
228	Monitors the given C<$port> and keeps the passed references. When the port
229	is killed, the references will be freed.
230
231	Optionally returns a guard that will stop the monitoring.
232
233	This function is useful when you create e.g. timers or other watchers and
234	want to free them when the port gets killed:
235
236	$port->rcv (start => sub {
237	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
238	undef $timer if 0.9 < rand;
239	});
240	});
241
242	=cut
243
244	sub mon_guard {
245	my ($port, @refs) = @_;
246
247	mon $port, sub { 0 && @refs }
248	}
249
250	=item $local_port = port	194	=item $local_port = port
251		195
252	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.
253		199
254	=item $portid = port { my @msg = @_; $finished }	200	=item $port = port { my @msg = @_; $finished }
255		201
256	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
257	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.
258		205
259	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
260	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
261	will be destroyed. Otherwise it will stay alive.	208	will be destroyed. Otherwise it will stay alive.
262		209
263	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
264	be passed to the callback.	211	be passed to the callback.
265		212
266	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:
267		214
268	my $port; $port = miniport {	215	my $port; $port = port {
269	snd $otherport, reply => $port;	216	snd $otherport, reply => $port;
270	};	217	};
271		218
272	=cut	219	=cut
		220
		221	sub rcv($@);
273		222
274	sub port(;&) {	223	sub port(;&) {
275	my $id = "$UNIQ." . $ID++;	224	my $id = "$UNIQ." . $ID++;
276	my $port = "$NODE#$id";	225	my $port = "$NODE#$id";
277		226
278	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) {
279	my $cb = shift;	298	my $cb = shift;
		299	delete $PORT_DATA{$portid};
280	$PORT{$id} = sub {	300	$PORT{$portid} = sub {
281	local $SELF = $port;	301	local $SELF = $port;
282	eval {	302	eval {
283	&$cb	303	&$cb
284	and kil $id;	304	and kil $port;
285	};	305	};
286	_self_die if $@;	306	_self_die if $@;
287	};	307	};
288	} else {	308	} else {
		309	my $self = $PORT_DATA{$portid} \|\|= do {
289	my $self = bless {	310	my $self = bless {
290	id => "$NODE#$id",	311	id => $port,
291	}, "AnyEvent::MP::Port";	312	}, "AnyEvent::MP::Port";
292		313
293	$PORT_DATA{$id} = $self;
294	$PORT{$id} = sub {	314	$PORT{$portid} = sub {
295	local $SELF = $port;	315	local $SELF = $port;
296		316
297	eval {	317	eval {
298	for (@{ $self->{rc0}{$_[0]} }) {	318	for (@{ $self->{rc0}{$_[0]} }) {
299	$_ && &{$_->[0]}	319	$_ && &{$_->[0]}
300	&& undef $_;	320	&& undef $_;
301	}	321	}
302		322
303	for (@{ $self->{rcv}{$_[0]} }) {	323	for (@{ $self->{rcv}{$_[0]} }) {
304	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	324	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
305	&& &{$_->[0]}	325	&& &{$_->[0]}
306	&& undef $_;	326	&& undef $_;
307	}	327	}
308		328
309	for (@{ $self->{any} }) {	329	for (@{ $self->{any} }) {
310	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	330	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
311	&& &{$_->[0]}	331	&& &{$_->[0]}
312	&& undef $_;	332	&& undef $_;
		333	}
313	}	334	};
		335	_self_die if $@;
314	};	336	};
315	_self_die if $@;	337
		338	$self
316	};	339	};
317	}
318		340
319	$port
320	}
321
322	=item reg $portid, $name
323
324	Registers the given port under the name C<$name>. If the name already
325	exists it is replaced.
326
327	A port can only be registered under one well known name.
328
329	A port automatically becomes unregistered when it is killed.
330
331	=cut
332
333	sub reg(@) {
334	my ($portid, $name) = @_;
335
336	$REG{$name} = $portid;
337	}
338
339	=item rcv $portid, tagstring => $callback->(@msg), ...
340
341	=item rcv $portid, $smartmatch => $callback->(@msg), ...
342
343	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
344
345	Register callbacks to be called on matching messages on the given port.
346
347	The callback has to return a true value when its work is done, after
348	which is will be removed, or a false value in which case it will stay
349	registered.
350
351	The global C<$SELF> (exported by this module) contains C<$portid> while
352	executing the callback.
353
354	Runtime errors wdurign callback execution will result in the port being
355	C<kil>ed.
356
357	If the match is an array reference, then it will be matched against the
358	first elements of the message, otherwise only the first element is being
359	matched.
360
361	Any element in the match that is specified as C<_any_> (a function
362	exported by this module) matches any single element of the message.
363
364	While not required, it is highly recommended that the first matching
365	element is a string identifying the message. The one-string-only match is
366	also the most efficient match (by far).
367
368	=cut
369
370	sub rcv($@) {
371	my ($noderef, $port) = split /#/, shift, 2;
372
373	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
374	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
375
376	my $self = $PORT_DATA{$port}
377	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
378
379	"AnyEvent::MP::Port" eq ref $self	341	"AnyEvent::MP::Port" eq ref $self
380	or Carp::croak "$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";
381		343
382	while (@_) {	344	while (@_) {
383	my ($match, $cb) = splice @_, 0, 2;	345	my ($match, $cb) = splice @_, 0, 2;
384		346
385	if (!ref $match) {	347	if (!ref $match) {
386	push @{ $self->{rc0}{$match} }, [$cb];	348	push @{ $self->{rc0}{$match} }, [$cb];
387	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	349	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
388	my ($type, @match) = @$match;	350	my ($type, @match) = @$match;
389	@match	351	@match
390	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	352	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
391	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	353	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
392	} else {	354	} else {
393	push @{ $self->{any} }, [$cb, $match];	355	push @{ $self->{any} }, [$cb, $match];
		356	}
394	}	357	}
395	}	358	}
		359
		360	$port
396	}	361	}
397		362
398	=item $closure = psub { BLOCK }	363	=item $closure = psub { BLOCK }
399		364
400	Remembers C<$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
…		…
431	$res	396	$res
432	}	397	}
433	}	398	}
434	}	399	}
435		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
436	=back	509	=back
437		510
438	=head1 FUNCTIONS FOR NODES	511	=head1 FUNCTIONS FOR NODES
439		512
440	=over 4	513	=over 4
441		514
442	=item become_public endpoint...	515	=item initialise_node $noderef, $seednode, $seednode...
443		516
444	Tells the node to become a public node, i.e. reachable from other nodes.	517	=item initialise_node "slave/", $master, $master...
445		518
446	If no arguments are given, or the first argument is C<undef>, then	519	Initialises a node - must be called exactly once before calling other
447	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	520	AnyEvent::MP functions when talking to other nodes is required.
448	local nodename resolves to.
449		521
450	Otherwise the first argument must be an array-reference with transport	522	All arguments are noderefs, which can be either resolved or unresolved.
451	endpoints ("ip:port", "hostname:port") or port numbers (in which case the	523
452	local nodename is used as hostname). The endpoints are all resolved and	524	There are two types of networked nodes, public nodes and slave nodes:
453	will become the node reference.	525
		526	=over 4
		527
		528	=item public nodes
		529
		530	For public nodes, C<$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";
454		574
455	=cut	575	=cut
456		576
457	=back	577	=back
458		578
…		…
461	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
462	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
463	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
464	the remaining arguments are simply the message data.	584	the remaining arguments are simply the message data.
465		585
		586	While other messages exist, they are not public and subject to change.
		587
466	=over 4	588	=over 4
467		589
468	=cut	590	=cut
469		591
470	=item lookup => $name, @reply	592	=item lookup => $name, @reply
…		…
498	snd $NODE, time => $myport, timereply => 1, 2;	620	snd $NODE, time => $myport, timereply => 1, 2;
499	# => snd $myport, timereply => 1, 2, <time>	621	# => snd $myport, timereply => 1, 2, <time>
500		622
501	=back	623	=back
502		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
503	=head1 SEE ALSO	712	=head1 SEE ALSO
504		713
505	L<AnyEvent>.	714	L<AnyEvent>.
506		715
507	=head1 AUTHOR	716	=head1 AUTHOR

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