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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.29 by root, Tue Aug 4 23:16:57 2009 UTC vs.
Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC

…		…
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
		13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# ports are message endpoints
		16
		17	# sending messages
13	snd $port, type => data...;	18	snd $port, type => data...;
		19	snd $port, @msg;
		20	snd @msg_with_first_element_being_a_port;
14		21
15	$SELF # receiving/own port id in rcv callbacks	22	# miniports
		23	my $miniport = port { my @msg = @_; 0 };
16		24
		25	# full ports
		26	my $port = port;
17	rcv $port, smartmatch => $cb->($port, @msg);	27	rcv $port, smartmatch => $cb->(@msg);
18
19	# examples:
20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
21	rcv $port1, pong => sub { warn "pong received\n" };	29	rcv $port, pong => sub { warn "pong received\n"; 0 };
22	snd $port2, ping => $port1;	30
		31	# remote ports
		32	my $port = spawn $node, $initfunc, @initdata;
23		33
24	# more, smarter, matches (_any_ is exported by this module)	34	# more, smarter, matches (_any_ is exported by this module)
25	rcv $port, [child_died => $pid] => sub { ...	35	rcv $port, [child_died => $pid] => sub { ...
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
27		37
		38	# monitoring
		39	mon $port, $cb->(@msg) # callback is invoked on death
		40	mon $port, $otherport # kill otherport on abnormal death
		41	mon $port, $otherport, @msg # send message on death
		42
28	=head1 DESCRIPTION	43	=head1 DESCRIPTION
29		44
30	This module (-family) implements a simple message passing framework.	45	This module (-family) implements a simple message passing framework.
31		46
32	Despite its simplicity, you can securely message other processes running	47	Despite its simplicity, you can securely message other processes running
…		…
53		68
54	=item port id - C<noderef#portname>	69	=item port id - C<noderef#portname>
55		70
56	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	71	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as
57	separator, and a port name (a printable string of unspecified format). An	72	separator, and a port name (a printable string of unspecified format). An
58	exception is the the node port, whose ID is identical to it's node	73	exception is the the node port, whose ID is identical to its node
59	reference.	74	reference.
60		75
61	=item node	76	=item node
62		77
63	A node is a single process containing at least one port - the node	78	A node is a single process containing at least one port - the node
…		…
90		105
91	=cut	106	=cut
92		107
93	package AnyEvent::MP;	108	package AnyEvent::MP;
94		109
95	use AnyEvent::MP::Base;	110	use AnyEvent::MP::Kernel;
96		111
97	use common::sense;	112	use common::sense;
98		113
99	use Carp ();	114	use Carp ();
100		115
101	use AE ();	116	use AE ();
102		117
103	use base "Exporter";	118	use base "Exporter";
104		119
105	our $VERSION = '0.1';	120	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		121
106	our @EXPORT = qw(	122	our @EXPORT = qw(
107	NODE $NODE *SELF node_of _any_	123	NODE $NODE *SELF node_of _any_
108	resolve_node	124	resolve_node initialise_node
109	become_slave become_public
110	snd rcv mon kil reg psub	125	snd rcv mon kil reg psub spawn
111	port	126	port
112	);	127	);
113		128
114	our $SELF;	129	our $SELF;
115		130
…		…
124	The C<NODE> function returns, and the C<$NODE> variable contains	139	The C<NODE> function returns, and the C<$NODE> variable contains
125	the noderef of the local node. The value is initialised by a call	140	the noderef of the local node. The value is initialised by a call
126	to C<become_public> or C<become_slave>, after which all local port	141	to C<become_public> or C<become_slave>, after which all local port
127	identifiers become invalid.	142	identifiers become invalid.
128		143
129	=item $noderef = node_of $portid	144	=item $noderef = node_of $port
130		145
131	Extracts and returns the noderef from a portid or a noderef.	146	Extracts and returns the noderef from a portid or a noderef.
		147
		148	=item initialise_node $noderef, $seednode, $seednode...
		149
		150	=item initialise_node "slave/", $master, $master...
		151
		152	Before a node can talk to other nodes on the network it has to initialise
		153	itself - the minimum a node needs to know is it's own name, and optionally
		154	it should know the noderefs of some other nodes in the network.
		155
		156	This function initialises a node - it must be called exactly once (or
		157	never) before calling other AnyEvent::MP functions.
		158
		159	All arguments are noderefs, which can be either resolved or unresolved.
		160
		161	There are two types of networked nodes, public nodes and slave nodes:
		162
		163	=over 4
		164
		165	=item public nodes
		166
		167	For public nodes, C<$noderef> must either be a (possibly unresolved)
		168	noderef, in which case it will be resolved, or C<undef> (or missing), in
		169	which case the noderef will be guessed.
		170
		171	Afterwards, the node will bind itself on all endpoints and try to connect
		172	to all additional C<$seednodes> that are specified. Seednodes are optional
		173	and can be used to quickly bootstrap the node into an existing network.
		174
		175	=item slave nodes
		176
		177	When the C<$noderef> is the special string C<slave/>, then the node will
		178	become a slave node. Slave nodes cannot be contacted from outside and will
		179	route most of their traffic to the master node that they attach to.
		180
		181	At least one additional noderef is required: The node will try to connect
		182	to all of them and will become a slave attached to the first node it can
		183	successfully connect to.
		184
		185	=back
		186
		187	This function will block until all nodes have been resolved and, for slave
		188	nodes, until it has successfully established a connection to a master
		189	server.
		190
		191	Example: become a public node listening on the default node.
		192
		193	initialise_node;
		194
		195	Example: become a public node, and try to contact some well-known master
		196	servers to become part of the network.
		197
		198	initialise_node undef, "master1", "master2";
		199
		200	Example: become a public node listening on port C<4041>.
		201
		202	initialise_node 4041;
		203
		204	Example: become a public node, only visible on localhost port 4044.
		205
		206	initialise_node "locahost:4044";
		207
		208	Example: become a slave node to any of the specified master servers.
		209
		210	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
132		211
133	=item $cv = resolve_node $noderef	212	=item $cv = resolve_node $noderef
134		213
135	Takes an unresolved node reference that may contain hostnames and	214	Takes an unresolved node reference that may contain hostnames and
136	abbreviated IDs, resolves all of them and returns a resolved node	215	abbreviated IDs, resolves all of them and returns a resolved node
…		…
168		247
169	Due to some quirks in how perl exports variables, it is impossible to	248	Due to some quirks in how perl exports variables, it is impossible to
170	just export C<$SELF>, all the symbols called C<SELF> are exported by this	249	just export C<$SELF>, all the symbols called C<SELF> are exported by this
171	module, but only C<$SELF> is currently used.	250	module, but only C<$SELF> is currently used.
172		251
173	=item snd $portid, type => @data	252	=item snd $port, type => @data
174		253
175	=item snd $portid, @msg	254	=item snd $port, @msg
176		255
177	Send the given message to the given port ID, which can identify either	256	Send the given message to the given port ID, which can identify either
178	a local or a remote port, and can be either a string or soemthignt hat	257	a local or a remote port, and can be either a string or soemthignt hat
179	stringifies a sa port ID (such as a port object :).	258	stringifies a sa port ID (such as a port object :).
180		259
…		…
190	JSON is used, then only strings, numbers and arrays and hashes consisting	269	JSON is used, then only strings, numbers and arrays and hashes consisting
191	of those are allowed (no objects). When Storable is used, then anything	270	of those are allowed (no objects). When Storable is used, then anything
192	that Storable can serialise and deserialise is allowed, and for the local	271	that Storable can serialise and deserialise is allowed, and for the local
193	node, anything can be passed.	272	node, anything can be passed.
194		273
195	=item kil $portid[, @reason]
196
197	Kill the specified port with the given C<@reason>.
198
199	If no C<@reason> is specified, then the port is killed "normally" (linked
200	ports will not be kileld, or even notified).
201
202	Otherwise, linked ports get killed with the same reason (second form of
203	C<mon>, see below).
204
205	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
206	will be reported as reason C<< die => $@ >>.
207
208	Transport/communication errors are reported as C<< transport_error =>
209	$message >>.
210
211	=item $guard = mon $portid, $cb->(@reason)
212
213	=item $guard = mon $portid, $otherport
214
215	=item $guard = mon $portid, $otherport, @msg
216
217	Monitor the given port and do something when the port is killed.
218
219	In the first form, the callback is simply called with any number
220	of C<@reason> elements (no @reason means that the port was deleted
221	"normally"). Note also that I<< the callback B<must> never die >>, so use
222	C<eval> if unsure.
223
224	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
225	a @reason was specified, i.e. on "normal" kils nothing happens, while
226	under all other conditions, the other port is killed with the same reason.
227
228	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
229
230	Example: call a given callback when C<$port> is killed.
231
232	mon $port, sub { warn "port died because of <@_>\n" };
233
234	Example: kill ourselves when C<$port> is killed abnormally.
235
236	mon $port, $self;
237
238	Example: send us a restart message another C<$port> is killed.
239
240	mon $port, $self => "restart";
241
242	=cut
243
244	sub mon {
245	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
246
247	my $node = $NODE{$noderef} \|\| add_node $noderef;
248
249	#TODO: ports must not be references
250	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
251	if (@_) {
252	# send a kill info message
253	my (@msg) = ($cb, @_);
254	$cb = sub { snd @msg, @_ };
255	} else {
256	# simply kill other port
257	my $port = $cb;
258	$cb = sub { kil $port, @_ if @_ };
259	}
260	}
261
262	$node->monitor ($port, $cb);
263
264	defined wantarray
265	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
266	}
267
268	=item $guard = mon_guard $port, $ref, $ref...
269
270	Monitors the given C<$port> and keeps the passed references. When the port
271	is killed, the references will be freed.
272
273	Optionally returns a guard that will stop the monitoring.
274
275	This function is useful when you create e.g. timers or other watchers and
276	want to free them when the port gets killed:
277
278	$port->rcv (start => sub {
279	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
280	undef $timer if 0.9 < rand;
281	});
282	});
283
284	=cut
285
286	sub mon_guard {
287	my ($port, @refs) = @_;
288
289	mon $port, sub { 0 && @refs }
290	}
291
292	=item lnk $port1, $port2
293
294	Link two ports. This is simply a shorthand for:
295
296	mon $port1, $port2;
297	mon $port2, $port1;
298
299	It means that if either one is killed abnormally, the other one gets
300	killed as well.
301
302	=item $local_port = port	274	=item $local_port = port
303		275
304	Create a new local port object that supports message matching.	276	Create a new local port object that can be used either as a pattern
		277	matching port ("full port") or a single-callback port ("miniport"),
		278	depending on how C<rcv> callbacks are bound to the object.
305		279
306	=item $portid = port { my @msg = @_; $finished }	280	=item $port = port { my @msg = @_; $finished }
307		281
308	Creates a "mini port", that is, a very lightweight port without any	282	Creates a "miniport", that is, a very lightweight port without any pattern
309	pattern matching behind it, and returns its ID.	283	matching behind it, and returns its ID. Semantically the same as creating
		284	a port and calling C<rcv $port, $callback> on it.
310		285
311	The block will be called for every message received on the port. When the	286	The block will be called for every message received on the port. When the
312	callback returns a true value its job is considered "done" and the port	287	callback returns a true value its job is considered "done" and the port
313	will be destroyed. Otherwise it will stay alive.	288	will be destroyed. Otherwise it will stay alive.
314		289
315	The message will be passed as-is, no extra argument (i.e. no port id) will	290	The message will be passed as-is, no extra argument (i.e. no port id) will
316	be passed to the callback.	291	be passed to the callback.
317		292
318	If you need the local port id in the callback, this works nicely:	293	If you need the local port id in the callback, this works nicely:
319		294
320	my $port; $port = miniport {	295	my $port; $port = port {
321	snd $otherport, reply => $port;	296	snd $otherport, reply => $port;
322	};	297	};
323		298
324	=cut	299	=cut
		300
		301	sub rcv($@);
325		302
326	sub port(;&) {	303	sub port(;&) {
327	my $id = "$UNIQ." . $ID++;	304	my $id = "$UNIQ." . $ID++;
328	my $port = "$NODE#$id";	305	my $port = "$NODE#$id";
329		306
330	if (@_) {	307	if (@_) {
		308	rcv $port, shift;
		309	} else {
		310	$PORT{$id} = sub { }; # nop
		311	}
		312
		313	$port
		314	}
		315
		316	=item reg $port, $name
		317
		318	=item reg $name
		319
		320	Registers the given port (or C<$SELF><<< if missing) under the name
		321	C<$name>. If the name already exists it is replaced.
		322
		323	A port can only be registered under one well known name.
		324
		325	A port automatically becomes unregistered when it is killed.
		326
		327	=cut
		328
		329	sub reg(@) {
		330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		331
		332	$REG{$_[0]} = $port;
		333	}
		334
		335	=item rcv $port, $callback->(@msg)
		336
		337	Replaces the callback on the specified miniport (after converting it to
		338	one if required).
		339
		340	=item rcv $port, tagstring => $callback->(@msg), ...
		341
		342	=item rcv $port, $smartmatch => $callback->(@msg), ...
		343
		344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		345
		346	Register callbacks to be called on matching messages on the given full
		347	port (after converting it to one if required) and return the port.
		348
		349	The callback has to return a true value when its work is done, after
		350	which is will be removed, or a false value in which case it will stay
		351	registered.
		352
		353	The global C<$SELF> (exported by this module) contains C<$port> while
		354	executing the callback.
		355
		356	Runtime errors during callback execution will result in the port being
		357	C<kil>ed.
		358
		359	If the match is an array reference, then it will be matched against the
		360	first elements of the message, otherwise only the first element is being
		361	matched.
		362
		363	Any element in the match that is specified as C<_any_> (a function
		364	exported by this module) matches any single element of the message.
		365
		366	While not required, it is highly recommended that the first matching
		367	element is a string identifying the message. The one-string-only match is
		368	also the most efficient match (by far).
		369
		370	Example: create a port and bind receivers on it in one go.
		371
		372	my $port = rcv port,
		373	msg1 => sub { ...; 0 },
		374	msg2 => sub { ...; 0 },
		375	;
		376
		377	Example: create a port, bind receivers and send it in a message elsewhere
		378	in one go:
		379
		380	snd $otherport, reply =>
		381	rcv port,
		382	msg1 => sub { ...; 0 },
		383	...
		384	;
		385
		386	=cut
		387
		388	sub rcv($@) {
		389	my $port = shift;
		390	my ($noderef, $portid) = split /#/, $port, 2;
		391
		392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		393	or Carp::croak "$port: rcv can only be called on local ports, caught";
		394
		395	if (@_ == 1) {
331	my $cb = shift;	396	my $cb = shift;
		397	delete $PORT_DATA{$portid};
332	$PORT{$id} = sub {	398	$PORT{$portid} = sub {
333	local $SELF = $port;	399	local $SELF = $port;
334	eval {	400	eval {
335	&$cb	401	&$cb
336	and kil $id;	402	and kil $port;
337	};	403	};
338	_self_die if $@;	404	_self_die if $@;
339	};	405	};
340	} else {	406	} else {
		407	my $self = $PORT_DATA{$portid} \|\|= do {
341	my $self = bless {	408	my $self = bless {
342	id => "$NODE#$id",	409	id => $port,
343	}, "AnyEvent::MP::Port";	410	}, "AnyEvent::MP::Port";
344		411
345	$PORT_DATA{$id} = $self;
346	$PORT{$id} = sub {	412	$PORT{$portid} = sub {
347	local $SELF = $port;	413	local $SELF = $port;
348		414
349	eval {	415	eval {
350	for (@{ $self->{rc0}{$_[0]} }) {	416	for (@{ $self->{rc0}{$_[0]} }) {
351	$_ && &{$_->[0]}	417	$_ && &{$_->[0]}
352	&& undef $_;	418	&& undef $_;
353	}	419	}
354		420
355	for (@{ $self->{rcv}{$_[0]} }) {	421	for (@{ $self->{rcv}{$_[0]} }) {
356	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
357	&& &{$_->[0]}	423	&& &{$_->[0]}
358	&& undef $_;	424	&& undef $_;
359	}	425	}
360		426
361	for (@{ $self->{any} }) {	427	for (@{ $self->{any} }) {
362	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
363	&& &{$_->[0]}	429	&& &{$_->[0]}
364	&& undef $_;	430	&& undef $_;
		431	}
365	}	432	};
		433	_self_die if $@;
366	};	434	};
367	_self_die if $@;	435
		436	$self
368	};	437	};
369	}
370		438
371	$port
372	}
373
374	=item reg $portid, $name
375
376	Registers the given port under the name C<$name>. If the name already
377	exists it is replaced.
378
379	A port can only be registered under one well known name.
380
381	A port automatically becomes unregistered when it is killed.
382
383	=cut
384
385	sub reg(@) {
386	my ($portid, $name) = @_;
387
388	$REG{$name} = $portid;
389	}
390
391	=item rcv $portid, tagstring => $callback->(@msg), ...
392
393	=item rcv $portid, $smartmatch => $callback->(@msg), ...
394
395	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
396
397	Register callbacks to be called on matching messages on the given port.
398
399	The callback has to return a true value when its work is done, after
400	which is will be removed, or a false value in which case it will stay
401	registered.
402
403	The global C<$SELF> (exported by this module) contains C<$portid> while
404	executing the callback.
405
406	Runtime errors wdurign callback execution will result in the port being
407	C<kil>ed.
408
409	If the match is an array reference, then it will be matched against the
410	first elements of the message, otherwise only the first element is being
411	matched.
412
413	Any element in the match that is specified as C<_any_> (a function
414	exported by this module) matches any single element of the message.
415
416	While not required, it is highly recommended that the first matching
417	element is a string identifying the message. The one-string-only match is
418	also the most efficient match (by far).
419
420	=cut
421
422	sub rcv($@) {
423	my ($noderef, $port) = split /#/, shift, 2;
424
425	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
426	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
427
428	my $self = $PORT_DATA{$port}
429	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
430
431	"AnyEvent::MP::Port" eq ref $self	439	"AnyEvent::MP::Port" eq ref $self
432	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";	440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
433		441
434	while (@_) {	442	while (@_) {
435	my ($match, $cb) = splice @_, 0, 2;	443	my ($match, $cb) = splice @_, 0, 2;
436		444
437	if (!ref $match) {	445	if (!ref $match) {
438	push @{ $self->{rc0}{$match} }, [$cb];	446	push @{ $self->{rc0}{$match} }, [$cb];
439	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
440	my ($type, @match) = @$match;	448	my ($type, @match) = @$match;
441	@match	449	@match
442	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
443	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
444	} else {	452	} else {
445	push @{ $self->{any} }, [$cb, $match];	453	push @{ $self->{any} }, [$cb, $match];
		454	}
446	}	455	}
447	}	456	}
		457
		458	$port
448	}	459	}
449		460
450	=item $closure = psub { BLOCK }	461	=item $closure = psub { BLOCK }
451		462
452	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	463	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
…		…
483	$res	494	$res
484	}	495	}
485	}	496	}
486	}	497	}
487		498
488	=back	499	=item $guard = mon $port, $cb->(@reason)
489		500
490	=head1 FUNCTIONS FOR NODES	501	=item $guard = mon $port, $rcvport
491		502
492	=over 4	503	=item $guard = mon $port
493		504
494	=item become_public $noderef	505	=item $guard = mon $port, $rcvport, @msg
495		506
496	Tells the node to become a public node, i.e. reachable from other nodes.	507	Monitor the given port and do something when the port is killed or
		508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
497		510
498	The first argument is the (unresolved) node reference of the local node	511	C<mon> effectively guarantees that, in the absence of hardware failures,
499	(if missing then the empty string is used).	512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
500		518
501	It is quite common to not specify anything, in which case the local node	519	In the first form (callback), the callback is simply called with any
502	tries to listen on the default port, or to only specify a port number, in	520	number of C<@reason> elements (no @reason means that the port was deleted
503	which case AnyEvent::MP tries to guess the local addresses.	521	"normally"). Note also that I<< the callback B<must> never die >>, so use
		522	C<eval> if unsure.
504		523
		524	In the second form (another port given), the other port (C<$rcvport>)
		525	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
		526	"normal" kils nothing happens, while under all other conditions, the other
		527	port is killed with the same reason.
		528
		529	The third form (kill self) is the same as the second form, except that
		530	C<$rvport> defaults to C<$SELF>.
		531
		532	In the last form (message), a message of the form C<@msg, @reason> will be
		533	C<snd>.
		534
		535	As a rule of thumb, monitoring requests should always monitor a port from
		536	a local port (or callback). The reason is that kill messages might get
		537	lost, just like any other message. Another less obvious reason is that
		538	even monitoring requests can get lost (for exmaple, when the connection
		539	to the other node goes down permanently). When monitoring a port locally
		540	these problems do not exist.
		541
		542	Example: call a given callback when C<$port> is killed.
		543
		544	mon $port, sub { warn "port died because of <@_>\n" };
		545
		546	Example: kill ourselves when C<$port> is killed abnormally.
		547
		548	mon $port;
		549
		550	Example: send us a restart message when another C<$port> is killed.
		551
		552	mon $port, $self => "restart";
		553
505	=cut	554	=cut
		555
		556	sub mon {
		557	my ($noderef, $port) = split /#/, shift, 2;
		558
		559	my $node = $NODE{$noderef} \|\| add_node $noderef;
		560
		561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
		562
		563	unless (ref $cb) {
		564	if (@_) {
		565	# send a kill info message
		566	my (@msg) = ($cb, @_);
		567	$cb = sub { snd @msg, @_ };
		568	} else {
		569	# simply kill other port
		570	my $port = $cb;
		571	$cb = sub { kil $port, @_ if @_ };
		572	}
		573	}
		574
		575	$node->monitor ($port, $cb);
		576
		577	defined wantarray
		578	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		579	}
		580
		581	=item $guard = mon_guard $port, $ref, $ref...
		582
		583	Monitors the given C<$port> and keeps the passed references. When the port
		584	is killed, the references will be freed.
		585
		586	Optionally returns a guard that will stop the monitoring.
		587
		588	This function is useful when you create e.g. timers or other watchers and
		589	want to free them when the port gets killed:
		590
		591	$port->rcv (start => sub {
		592	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		593	undef $timer if 0.9 < rand;
		594	});
		595	});
		596
		597	=cut
		598
		599	sub mon_guard {
		600	my ($port, @refs) = @_;
		601
		602	#TODO: mon-less form?
		603
		604	mon $port, sub { 0 && @refs }
		605	}
		606
		607	=item kil $port[, @reason]
		608
		609	Kill the specified port with the given C<@reason>.
		610
		611	If no C<@reason> is specified, then the port is killed "normally" (linked
		612	ports will not be kileld, or even notified).
		613
		614	Otherwise, linked ports get killed with the same reason (second form of
		615	C<mon>, see below).
		616
		617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		618	will be reported as reason C<< die => $@ >>.
		619
		620	Transport/communication errors are reported as C<< transport_error =>
		621	$message >>.
		622
		623	=cut
		624
		625	=item $port = spawn $node, $initfunc[, @initdata]
		626
		627	Creates a port on the node C<$node> (which can also be a port ID, in which
		628	case it's the node where that port resides).
		629
		630	The port ID of the newly created port is return immediately, and it is
		631	permissible to immediately start sending messages or monitor the port.
		632
		633	After the port has been created, the init function is
		634	called. This function must be a fully-qualified function name
		635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		636	program, use C<::name>.
		637
		638	If the function doesn't exist, then the node tries to C<require>
		639	the package, then the package above the package and so on (e.g.
		640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		641	exists or it runs out of package names.
		642
		643	The init function is then called with the newly-created port as context
		644	object (C<$SELF>) and the C<@initdata> values as arguments.
		645
		646	A common idiom is to pass your own port, monitor the spawned port, and
		647	in the init function, monitor the original port. This two-way monitoring
		648	ensures that both ports get cleaned up when there is a problem.
		649
		650	Example: spawn a chat server port on C<$othernode>.
		651
		652	# this node, executed from within a port context:
		653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		654	mon $server;
		655
		656	# init function on C<$othernode>
		657	sub connect {
		658	my ($srcport) = @_;
		659
		660	mon $srcport;
		661
		662	rcv $SELF, sub {
		663	...
		664	};
		665	}
		666
		667	=cut
		668
		669	sub _spawn {
		670	my $port = shift;
		671	my $init = shift;
		672
		673	local $SELF = "$NODE#$port";
		674	eval {
		675	&{ load_func $init }
		676	};
		677	_self_die if $@;
		678	}
		679
		680	sub spawn(@) {
		681	my ($noderef, undef) = split /#/, shift, 2;
		682
		683	my $id = "$RUNIQ." . $ID++;
		684
		685	$_[0] =~ /::/
		686	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		687
		688	($NODE{$noderef} \|\| add_node $noderef)
		689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		690
		691	"$noderef#$id"
		692	}
506		693
507	=back	694	=back
508		695
509	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
510		697
…		…
552		739
553	=back	740	=back
554		741
555	=head1 AnyEvent::MP vs. Distributed Erlang	742	=head1 AnyEvent::MP vs. Distributed Erlang
556		743
557	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node	744	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
558	== aemp node, erlang process == aemp port), so many of the documents and	745	== aemp node, Erlang process == aemp port), so many of the documents and
559	programming techniques employed by erlang apply to AnyEvent::MP. Here is a	746	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
560	sample:	747	sample:
561		748
562	http://www.erlang.se/doc/programming_rules.shtml	749	http://www.Erlang.se/doc/programming_rules.shtml
563	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	750	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
564	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6	751	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
565	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5	752	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
566		753
567	Despite the similarities, there are also some important differences:	754	Despite the similarities, there are also some important differences:
568		755
569	=over 4	756	=over 4
570		757
…		…
581		768
582	Erlang uses processes that selctively receive messages, and therefore	769	Erlang uses processes that selctively receive messages, and therefore
583	needs a queue. AEMP is event based, queuing messages would serve no useful	770	needs a queue. AEMP is event based, queuing messages would serve no useful
584	purpose.	771	purpose.
585		772
586	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).	773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
587		774
588	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
589		776
590	Sending messages in erlang is synchronous and blocks the process. AEMP	777	Sending messages in Erlang is synchronous and blocks the process. AEMP
591	sends are immediate, connection establishment is handled in the	778	sends are immediate, connection establishment is handled in the
592	background.	779	background.
593		780
594	=item * Erlang can silently lose messages, AEMP cannot.	781	=item * Erlang can silently lose messages, AEMP cannot.
595		782
…		…
598	and c, and the other side only receives messages a and c).	785	and c, and the other side only receives messages a and c).
599		786
600	AEMP guarantees correct ordering, and the guarantee that there are no	787	AEMP guarantees correct ordering, and the guarantee that there are no
601	holes in the message sequence.	788	holes in the message sequence.
602		789
603	=item * In erlang, processes can be declared dead and later be found to be	790	=item * In Erlang, processes can be declared dead and later be found to be
604	alive.	791	alive.
605		792
606	In erlang it can happen that a monitored process is declared dead and	793	In Erlang it can happen that a monitored process is declared dead and
607	linked processes get killed, but later it turns out that the process is	794	linked processes get killed, but later it turns out that the process is
608	still alive - and can receive messages.	795	still alive - and can receive messages.
609		796
610	In AEMP, when port monitoring detects a port as dead, then that port will	797	In AEMP, when port monitoring detects a port as dead, then that port will
611	eventually be killed - it cannot happen that a node detects a port as dead	798	eventually be killed - it cannot happen that a node detects a port as dead
612	and then later sends messages to it, finding it is still alive.	799	and then later sends messages to it, finding it is still alive.
613		800
614	=item * Erlang can send messages to the wrong port, AEMP does not.	801	=item * Erlang can send messages to the wrong port, AEMP does not.
615		802
616	In erlang it is quite possible that a node that restarts reuses a process	803	In Erlang it is quite possible that a node that restarts reuses a process
617	ID known to other nodes for a completely different process, causing	804	ID known to other nodes for a completely different process, causing
618	messages destined for that process to end up in an unrelated process.	805	messages destined for that process to end up in an unrelated process.
619		806
620	AEMP never reuses port IDs, so old messages or old port IDs floating	807	AEMP never reuses port IDs, so old messages or old port IDs floating
621	around in the network will not be sent to an unrelated port.	808	around in the network will not be sent to an unrelated port.
…		…
627	securely authenticate nodes.	814	securely authenticate nodes.
628		815
629	=item * The AEMP protocol is optimised for both text-based and binary	816	=item * The AEMP protocol is optimised for both text-based and binary
630	communications.	817	communications.
631		818
632	The AEMP protocol, unlike the erlang protocol, supports both	819	The AEMP protocol, unlike the Erlang protocol, supports both
633	language-independent text-only protocols (good for debugging) and binary,	820	language-independent text-only protocols (good for debugging) and binary,
634	language-specific serialisers (e.g. Storable).	821	language-specific serialisers (e.g. Storable).
635		822
636	It has also been carefully designed to be implementable in other languages	823	It has also been carefully designed to be implementable in other languages
637	with a minimum of work while gracefully degrading fucntionality to make the	824	with a minimum of work while gracefully degrading fucntionality to make the
638	protocol simple.	825	protocol simple.
639		826
		827	=item * AEMP has more flexible monitoring options than Erlang.
		828
		829	In Erlang, you can chose to receive I<all> exit signals as messages
		830	or I<none>, there is no in-between, so monitoring single processes is
		831	difficult to implement. Monitoring in AEMP is more flexible than in
		832	Erlang, as one can choose between automatic kill, exit message or callback
		833	on a per-process basis.
		834
		835	=item * Erlang tries to hide remote/local connections, AEMP does not.
		836
		837	Monitoring in Erlang is not an indicator of process death/crashes,
		838	as linking is (except linking is unreliable in Erlang).
		839
		840	In AEMP, you don't "look up" registered port names or send to named ports
		841	that might or might not be persistent. Instead, you normally spawn a port
		842	on the remote node. The init function monitors the you, and you monitor
		843	the remote port. Since both monitors are local to the node, they are much
		844	more reliable.
		845
		846	This also saves round-trips and avoids sending messages to the wrong port
		847	(hard to do in Erlang).
		848
640	=back	849	=back
641		850
642	=head1 SEE ALSO	851	=head1 SEE ALSO
643		852
644	L<AnyEvent>.	853	L<AnyEvent>.

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Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC