[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 1.42 by root, Sun Aug 9 00:41:49 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
…		…
103	use base "Exporter";	118	use base "Exporter";
104		119
105	our $VERSION = '0.1';	120	our $VERSION = '0.1';
106	our @EXPORT = qw(	121	our @EXPORT = qw(
107	NODE $NODE *SELF node_of _any_	122	NODE $NODE *SELF node_of _any_
108	resolve_node	123	resolve_node initialise_node
109	become_slave become_public
110	snd rcv mon kil reg psub	124	snd rcv mon kil reg psub spawn
111	port	125	port
112	);	126	);
113		127
114	our $SELF;	128	our $SELF;
115		129
…		…
124	The C<NODE> function returns, and the C<$NODE> variable contains	138	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	139	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	140	to C<become_public> or C<become_slave>, after which all local port
127	identifiers become invalid.	141	identifiers become invalid.
128		142
129	=item $noderef = node_of $portid	143	=item $noderef = node_of $port
130		144
131	Extracts and returns the noderef from a portid or a noderef.	145	Extracts and returns the noderef from a portid or a noderef.
		146
		147	=item initialise_node $noderef, $seednode, $seednode...
		148
		149	=item initialise_node "slave/", $master, $master...
		150
		151	Before a node can talk to other nodes on the network it has to initialise
		152	itself - the minimum a node needs to know is it's own name, and optionally
		153	it should know the noderefs of some other nodes in the network.
		154
		155	This function initialises a node - it must be called exactly once (or
		156	never) before calling other AnyEvent::MP functions.
		157
		158	All arguments are noderefs, which can be either resolved or unresolved.
		159
		160	There are two types of networked nodes, public nodes and slave nodes:
		161
		162	=over 4
		163
		164	=item public nodes
		165
		166	For public nodes, C<$noderef> must either be a (possibly unresolved)
		167	noderef, in which case it will be resolved, or C<undef> (or missing), in
		168	which case the noderef will be guessed.
		169
		170	Afterwards, the node will bind itself on all endpoints and try to connect
		171	to all additional C<$seednodes> that are specified. Seednodes are optional
		172	and can be used to quickly bootstrap the node into an existing network.
		173
		174	=item slave nodes
		175
		176	When the C<$noderef> is the special string C<slave/>, then the node will
		177	become a slave node. Slave nodes cannot be contacted from outside and will
		178	route most of their traffic to the master node that they attach to.
		179
		180	At least one additional noderef is required: The node will try to connect
		181	to all of them and will become a slave attached to the first node it can
		182	successfully connect to.
		183
		184	=back
		185
		186	This function will block until all nodes have been resolved and, for slave
		187	nodes, until it has successfully established a connection to a master
		188	server.
		189
		190	Example: become a public node listening on the default node.
		191
		192	initialise_node;
		193
		194	Example: become a public node, and try to contact some well-known master
		195	servers to become part of the network.
		196
		197	initialise_node undef, "master1", "master2";
		198
		199	Example: become a public node listening on port C<4041>.
		200
		201	initialise_node 4041;
		202
		203	Example: become a public node, only visible on localhost port 4044.
		204
		205	initialise_node "locahost:4044";
		206
		207	Example: become a slave node to any of the specified master servers.
		208
		209	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
132		210
133	=item $cv = resolve_node $noderef	211	=item $cv = resolve_node $noderef
134		212
135	Takes an unresolved node reference that may contain hostnames and	213	Takes an unresolved node reference that may contain hostnames and
136	abbreviated IDs, resolves all of them and returns a resolved node	214	abbreviated IDs, resolves all of them and returns a resolved node
…		…
168		246
169	Due to some quirks in how perl exports variables, it is impossible to	247	Due to some quirks in how perl exports variables, it is impossible to
170	just export C<$SELF>, all the symbols called C<SELF> are exported by this	248	just export C<$SELF>, all the symbols called C<SELF> are exported by this
171	module, but only C<$SELF> is currently used.	249	module, but only C<$SELF> is currently used.
172		250
173	=item snd $portid, type => @data	251	=item snd $port, type => @data
174		252
175	=item snd $portid, @msg	253	=item snd $port, @msg
176		254
177	Send the given message to the given port ID, which can identify either	255	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	256	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 :).	257	stringifies a sa port ID (such as a port object :).
180		258
…		…
190	JSON is used, then only strings, numbers and arrays and hashes consisting	268	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	269	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	270	that Storable can serialise and deserialise is allowed, and for the local
193	node, anything can be passed.	271	node, anything can be passed.
194		272
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	273	=item $local_port = port
303		274
304	Create a new local port object that supports message matching.	275	Create a new local port object that can be used either as a pattern
		276	matching port ("full port") or a single-callback port ("miniport"),
		277	depending on how C<rcv> callbacks are bound to the object.
305		278
306	=item $portid = port { my @msg = @_; $finished }	279	=item $port = port { my @msg = @_; $finished }
307		280
308	Creates a "mini port", that is, a very lightweight port without any	281	Creates a "miniport", that is, a very lightweight port without any pattern
309	pattern matching behind it, and returns its ID.	282	matching behind it, and returns its ID. Semantically the same as creating
		283	a port and calling C<rcv $port, $callback> on it.
310		284
311	The block will be called for every message received on the port. When the	285	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	286	callback returns a true value its job is considered "done" and the port
313	will be destroyed. Otherwise it will stay alive.	287	will be destroyed. Otherwise it will stay alive.
314		288
315	The message will be passed as-is, no extra argument (i.e. no port id) will	289	The message will be passed as-is, no extra argument (i.e. no port id) will
316	be passed to the callback.	290	be passed to the callback.
317		291
318	If you need the local port id in the callback, this works nicely:	292	If you need the local port id in the callback, this works nicely:
319		293
320	my $port; $port = miniport {	294	my $port; $port = port {
321	snd $otherport, reply => $port;	295	snd $otherport, reply => $port;
322	};	296	};
323		297
324	=cut	298	=cut
		299
		300	sub rcv($@);
325		301
326	sub port(;&) {	302	sub port(;&) {
327	my $id = "$UNIQ." . $ID++;	303	my $id = "$UNIQ." . $ID++;
328	my $port = "$NODE#$id";	304	my $port = "$NODE#$id";
329		305
330	if (@_) {	306	if (@_) {
		307	rcv $port, shift;
		308	} else {
		309	$PORT{$id} = sub { }; # nop
		310	}
		311
		312	$port
		313	}
		314
		315	=item reg $port, $name
		316
		317	=item reg $name
		318
		319	Registers the given port (or C<$SELF><<< if missing) under the name
		320	C<$name>. If the name already exists it is replaced.
		321
		322	A port can only be registered under one well known name.
		323
		324	A port automatically becomes unregistered when it is killed.
		325
		326	=cut
		327
		328	sub reg(@) {
		329	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		330
		331	$REG{$_[0]} = $port;
		332	}
		333
		334	=item rcv $port, $callback->(@msg)
		335
		336	Replaces the callback on the specified miniport (after converting it to
		337	one if required).
		338
		339	=item rcv $port, tagstring => $callback->(@msg), ...
		340
		341	=item rcv $port, $smartmatch => $callback->(@msg), ...
		342
		343	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		344
		345	Register callbacks to be called on matching messages on the given full
		346	port (after converting it to one if required) and return the port.
		347
		348	The callback has to return a true value when its work is done, after
		349	which is will be removed, or a false value in which case it will stay
		350	registered.
		351
		352	The global C<$SELF> (exported by this module) contains C<$port> while
		353	executing the callback.
		354
		355	Runtime errors during callback execution will result in the port being
		356	C<kil>ed.
		357
		358	If the match is an array reference, then it will be matched against the
		359	first elements of the message, otherwise only the first element is being
		360	matched.
		361
		362	Any element in the match that is specified as C<_any_> (a function
		363	exported by this module) matches any single element of the message.
		364
		365	While not required, it is highly recommended that the first matching
		366	element is a string identifying the message. The one-string-only match is
		367	also the most efficient match (by far).
		368
		369	Example: create a port and bind receivers on it in one go.
		370
		371	my $port = rcv port,
		372	msg1 => sub { ...; 0 },
		373	msg2 => sub { ...; 0 },
		374	;
		375
		376	Example: create a port, bind receivers and send it in a message elsewhere
		377	in one go:
		378
		379	snd $otherport, reply =>
		380	rcv port,
		381	msg1 => sub { ...; 0 },
		382	...
		383	;
		384
		385	=cut
		386
		387	sub rcv($@) {
		388	my $port = shift;
		389	my ($noderef, $portid) = split /#/, $port, 2;
		390
		391	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		392	or Carp::croak "$port: rcv can only be called on local ports, caught";
		393
		394	if (@_ == 1) {
331	my $cb = shift;	395	my $cb = shift;
		396	delete $PORT_DATA{$portid};
332	$PORT{$id} = sub {	397	$PORT{$portid} = sub {
333	local $SELF = $port;	398	local $SELF = $port;
334	eval {	399	eval {
335	&$cb	400	&$cb
336	and kil $id;	401	and kil $port;
337	};	402	};
338	_self_die if $@;	403	_self_die if $@;
339	};	404	};
340	} else {	405	} else {
		406	my $self = $PORT_DATA{$portid} \|\|= do {
341	my $self = bless {	407	my $self = bless {
342	id => "$NODE#$id",	408	id => $port,
343	}, "AnyEvent::MP::Port";	409	}, "AnyEvent::MP::Port";
344		410
345	$PORT_DATA{$id} = $self;
346	$PORT{$id} = sub {	411	$PORT{$portid} = sub {
347	local $SELF = $port;	412	local $SELF = $port;
348		413
349	eval {	414	eval {
350	for (@{ $self->{rc0}{$_[0]} }) {	415	for (@{ $self->{rc0}{$_[0]} }) {
351	$_ && &{$_->[0]}	416	$_ && &{$_->[0]}
352	&& undef $_;	417	&& undef $_;
353	}	418	}
354		419
355	for (@{ $self->{rcv}{$_[0]} }) {	420	for (@{ $self->{rcv}{$_[0]} }) {
356	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
357	&& &{$_->[0]}	422	&& &{$_->[0]}
358	&& undef $_;	423	&& undef $_;
359	}	424	}
360		425
361	for (@{ $self->{any} }) {	426	for (@{ $self->{any} }) {
362	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
363	&& &{$_->[0]}	428	&& &{$_->[0]}
364	&& undef $_;	429	&& undef $_;
		430	}
365	}	431	};
		432	_self_die if $@;
366	};	433	};
367	_self_die if $@;	434
		435	$self
368	};	436	};
369	}
370		437
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	438	"AnyEvent::MP::Port" eq ref $self
432	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";	439	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
433		440
434	while (@_) {	441	while (@_) {
435	my ($match, $cb) = splice @_, 0, 2;	442	my ($match, $cb) = splice @_, 0, 2;
436		443
437	if (!ref $match) {	444	if (!ref $match) {
438	push @{ $self->{rc0}{$match} }, [$cb];	445	push @{ $self->{rc0}{$match} }, [$cb];
439	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
440	my ($type, @match) = @$match;	447	my ($type, @match) = @$match;
441	@match	448	@match
442	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
443	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
444	} else {	451	} else {
445	push @{ $self->{any} }, [$cb, $match];	452	push @{ $self->{any} }, [$cb, $match];
		453	}
446	}	454	}
447	}	455	}
		456
		457	$port
448	}	458	}
449		459
450	=item $closure = psub { BLOCK }	460	=item $closure = psub { BLOCK }
451		461
452	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	462	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
…		…
483	$res	493	$res
484	}	494	}
485	}	495	}
486	}	496	}
487		497
488	=back	498	=item $guard = mon $port, $cb->(@reason)
489		499
490	=head1 FUNCTIONS FOR NODES	500	=item $guard = mon $port, $rcvport
491		501
492	=over 4	502	=item $guard = mon $port
493		503
494	=item become_public $noderef	504	=item $guard = mon $port, $rcvport, @msg
495		505
496	Tells the node to become a public node, i.e. reachable from other nodes.	506	Monitor the given port and do something when the port is killed or
		507	messages to it were lost, and optionally return a guard that can be used
		508	to stop monitoring again.
497		509
498	The first argument is the (unresolved) node reference of the local node	510	C<mon> effectively guarantees that, in the absence of hardware failures,
499	(if missing then the empty string is used).	511	that after starting the monitor, either all messages sent to the port
		512	will arrive, or the monitoring action will be invoked after possible
		513	message loss has been detected. No messages will be lost "in between"
		514	(after the first lost message no further messages will be received by the
		515	port). After the monitoring action was invoked, further messages might get
		516	delivered again.
500		517
501	It is quite common to not specify anything, in which case the local node	518	In the first form (callback), the callback is simply called with any
502	tries to listen on the default port, or to only specify a port number, in	519	number of C<@reason> elements (no @reason means that the port was deleted
503	which case AnyEvent::MP tries to guess the local addresses.	520	"normally"). Note also that I<< the callback B<must> never die >>, so use
		521	C<eval> if unsure.
504		522
		523	In the second form (another port given), the other port (C<$rcvport)
		524	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
		525	"normal" kils nothing happens, while under all other conditions, the other
		526	port is killed with the same reason.
		527
		528	The third form (kill self) is the same as the second form, except that
		529	C<$rvport> defaults to C<$SELF>.
		530
		531	In the last form (message), a message of the form C<@msg, @reason> will be
		532	C<snd>.
		533
		534	As a rule of thumb, monitoring requests should always monitor a port from
		535	a local port (or callback). The reason is that kill messages might get
		536	lost, just like any other message. Another less obvious reason is that
		537	even monitoring requests can get lost (for exmaple, when the connection
		538	to the other node goes down permanently). When monitoring a port locally
		539	these problems do not exist.
		540
		541	Example: call a given callback when C<$port> is killed.
		542
		543	mon $port, sub { warn "port died because of <@_>\n" };
		544
		545	Example: kill ourselves when C<$port> is killed abnormally.
		546
		547	mon $port;
		548
		549	Example: send us a restart message when another C<$port> is killed.
		550
		551	mon $port, $self => "restart";
		552
505	=cut	553	=cut
		554
		555	sub mon {
		556	my ($noderef, $port) = split /#/, shift, 2;
		557
		558	my $node = $NODE{$noderef} \|\| add_node $noderef;
		559
		560	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
		561
		562	unless (ref $cb) {
		563	if (@_) {
		564	# send a kill info message
		565	my (@msg) = ($cb, @_);
		566	$cb = sub { snd @msg, @_ };
		567	} else {
		568	# simply kill other port
		569	my $port = $cb;
		570	$cb = sub { kil $port, @_ if @_ };
		571	}
		572	}
		573
		574	$node->monitor ($port, $cb);
		575
		576	defined wantarray
		577	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		578	}
		579
		580	=item $guard = mon_guard $port, $ref, $ref...
		581
		582	Monitors the given C<$port> and keeps the passed references. When the port
		583	is killed, the references will be freed.
		584
		585	Optionally returns a guard that will stop the monitoring.
		586
		587	This function is useful when you create e.g. timers or other watchers and
		588	want to free them when the port gets killed:
		589
		590	$port->rcv (start => sub {
		591	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		592	undef $timer if 0.9 < rand;
		593	});
		594	});
		595
		596	=cut
		597
		598	sub mon_guard {
		599	my ($port, @refs) = @_;
		600
		601	#TODO: mon-less form?
		602
		603	mon $port, sub { 0 && @refs }
		604	}
		605
		606	=item kil $port[, @reason]
		607
		608	Kill the specified port with the given C<@reason>.
		609
		610	If no C<@reason> is specified, then the port is killed "normally" (linked
		611	ports will not be kileld, or even notified).
		612
		613	Otherwise, linked ports get killed with the same reason (second form of
		614	C<mon>, see below).
		615
		616	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		617	will be reported as reason C<< die => $@ >>.
		618
		619	Transport/communication errors are reported as C<< transport_error =>
		620	$message >>.
		621
		622	=cut
		623
		624	=item $port = spawn $node, $initfunc[, @initdata]
		625
		626	Creates a port on the node C<$node> (which can also be a port ID, in which
		627	case it's the node where that port resides).
		628
		629	The port ID of the newly created port is return immediately, and it is
		630	permissible to immediately start sending messages or monitor the port.
		631
		632	After the port has been created, the init function is
		633	called. This function must be a fully-qualified function name
		634	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		635	program, use C<::name>.
		636
		637	If the function doesn't exist, then the node tries to C<require>
		638	the package, then the package above the package and so on (e.g.
		639	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		640	exists or it runs out of package names.
		641
		642	The init function is then called with the newly-created port as context
		643	object (C<$SELF>) and the C<@initdata> values as arguments.
		644
		645	A common idiom is to pass your own port, monitor the spawned port, and
		646	in the init function, monitor the original port. This two-way monitoring
		647	ensures that both ports get cleaned up when there is a problem.
		648
		649	Example: spawn a chat server port on C<$othernode>.
		650
		651	# this node, executed from within a port context:
		652	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		653	mon $server;
		654
		655	# init function on C<$othernode>
		656	sub connect {
		657	my ($srcport) = @_;
		658
		659	mon $srcport;
		660
		661	rcv $SELF, sub {
		662	...
		663	};
		664	}
		665
		666	=cut
		667
		668	sub _spawn {
		669	my $port = shift;
		670	my $init = shift;
		671
		672	local $SELF = "$NODE#$port";
		673	eval {
		674	&{ load_func $init }
		675	};
		676	_self_die if $@;
		677	}
		678
		679	sub spawn(@) {
		680	my ($noderef, undef) = split /#/, shift, 2;
		681
		682	my $id = "$RUNIQ." . $ID++;
		683
		684	$_[0] =~ /::/
		685	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		686
		687	($NODE{$noderef} \|\| add_node $noderef)
		688	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		689
		690	"$noderef#$id"
		691	}
506		692
507	=back	693	=back
508		694
509	=head1 NODE MESSAGES	695	=head1 NODE MESSAGES
510		696
…		…
552		738
553	=back	739	=back
554		740
555	=head1 AnyEvent::MP vs. Distributed Erlang	741	=head1 AnyEvent::MP vs. Distributed Erlang
556		742
557	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node	743	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	744	== 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	745	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
560	sample:	746	sample:
561		747
562	http://www.erlang.se/doc/programming_rules.shtml	748	http://www.Erlang.se/doc/programming_rules.shtml
563	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	749	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	750	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	751	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
566		752
567	Despite the similarities, there are also some important differences:	753	Despite the similarities, there are also some important differences:
568		754
569	=over 4	755	=over 4
570		756
…		…
581		767
582	Erlang uses processes that selctively receive messages, and therefore	768	Erlang uses processes that selctively receive messages, and therefore
583	needs a queue. AEMP is event based, queuing messages would serve no useful	769	needs a queue. AEMP is event based, queuing messages would serve no useful
584	purpose.	770	purpose.
585		771
586	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).	772	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
587		773
588	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	774	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
589		775
590	Sending messages in erlang is synchronous and blocks the process. AEMP	776	Sending messages in Erlang is synchronous and blocks the process. AEMP
591	sends are immediate, connection establishment is handled in the	777	sends are immediate, connection establishment is handled in the
592	background.	778	background.
593		779
594	=item * Erlang can silently lose messages, AEMP cannot.	780	=item * Erlang can silently lose messages, AEMP cannot.
595		781
…		…
598	and c, and the other side only receives messages a and c).	784	and c, and the other side only receives messages a and c).
599		785
600	AEMP guarantees correct ordering, and the guarantee that there are no	786	AEMP guarantees correct ordering, and the guarantee that there are no
601	holes in the message sequence.	787	holes in the message sequence.
602		788
603	=item * In erlang, processes can be declared dead and later be found to be	789	=item * In Erlang, processes can be declared dead and later be found to be
604	alive.	790	alive.
605		791
606	In erlang it can happen that a monitored process is declared dead and	792	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	793	linked processes get killed, but later it turns out that the process is
608	still alive - and can receive messages.	794	still alive - and can receive messages.
609		795
610	In AEMP, when port monitoring detects a port as dead, then that port will	796	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	797	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.	798	and then later sends messages to it, finding it is still alive.
613		799
614	=item * Erlang can send messages to the wrong port, AEMP does not.	800	=item * Erlang can send messages to the wrong port, AEMP does not.
615		801
616	In erlang it is quite possible that a node that restarts reuses a process	802	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	803	ID known to other nodes for a completely different process, causing
618	messages destined for that process to end up in an unrelated process.	804	messages destined for that process to end up in an unrelated process.
619		805
620	AEMP never reuses port IDs, so old messages or old port IDs floating	806	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.	807	around in the network will not be sent to an unrelated port.
…		…
627	securely authenticate nodes.	813	securely authenticate nodes.
628		814
629	=item * The AEMP protocol is optimised for both text-based and binary	815	=item * The AEMP protocol is optimised for both text-based and binary
630	communications.	816	communications.
631		817
632	The AEMP protocol, unlike the erlang protocol, supports both	818	The AEMP protocol, unlike the Erlang protocol, supports both
633	language-independent text-only protocols (good for debugging) and binary,	819	language-independent text-only protocols (good for debugging) and binary,
634	language-specific serialisers (e.g. Storable).	820	language-specific serialisers (e.g. Storable).
635		821
636	It has also been carefully designed to be implementable in other languages	822	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	823	with a minimum of work while gracefully degrading fucntionality to make the
638	protocol simple.	824	protocol simple.
639		825
		826	=item * AEMP has more flexible monitoring options than Erlang.
		827
		828	In Erlang, you can chose to receive I<all> exit signals as messages
		829	or I<none>, there is no in-between, so monitoring single processes is
		830	difficult to implement. Monitoring in AEMP is more flexible than in
		831	Erlang, as one can choose between automatic kill, exit message or callback
		832	on a per-process basis.
		833
		834	=item * Erlang tries to hide remote/local connections, AEMP does not.
		835
		836	Monitoring in Erlang is not an indicator of process death/crashes,
		837	as linking is (except linking is unreliable in Erlang).
		838
		839	In AEMP, you don't "look up" registered port names or send to named ports
		840	that might or might not be persistent. Instead, you normally spawn a port
		841	on the remote node. The init function monitors the you, and you monitor
		842	the remote port. Since both monitors are local to the node, they are much
		843	more reliable.
		844
		845	This also saves round-trips and avoids sending messages to the wrong port
		846	(hard to do in Erlang).
		847
640	=back	848	=back
641		849
642	=head1 SEE ALSO	850	=head1 SEE ALSO
643		851
644	L<AnyEvent>.	852	L<AnyEvent>.

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Revision 1.42 by root, Sun Aug 9 00:41:49 2009 UTC