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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.23 by root, Tue Aug 4 18:46:16 2009 UTC vs.
Revision 1.39 by root, Fri Aug 7 23:21:48 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
…		…
43		58
44	=over 4	59	=over 4
45		60
46	=item port	61	=item port
47		62
48	A port is something you can send messages to with the C<snd> function, and	63	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	64
50	messages they match, messages will not be queued.	65	Some ports allow you to register C<rcv> handlers that can match specific
		66	messages. All C<rcv> handlers will receive messages they match, messages
		67	will not be queued.
51		68
52	=item port id - C<noderef#portname>	69	=item port id - C<noderef#portname>
53		70
54	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	71	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).	72	separator, and a port name (a printable string of unspecified format). An
		73	exception is the the node port, whose ID is identical to its node
		74	reference.
56		75
57	=item node	76	=item node
58		77
59	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
60	port. You can send messages to node ports to let them create new ports,	79	port. You can send messages to node ports to find existing ports or to
61	among other things.	80	create new ports, among other things.
62		81
63	Initially, nodes are either private (single-process only) or hidden	82	Nodes are either private (single-process only), slaves (connected to a
64	(connected to a master node only). Only when they epxlicitly "become	83	master node only) or public nodes (connectable from unrelated nodes).
65	public" can you send them messages from unrelated other nodes.
66		84
67	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
68		86
69	A noderef is a string that either uniquely identifies a given node (for	87	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	88	private and slave nodes), or contains a recipe on how to reach a given
71	node (for public nodes).	89	node (for public nodes).
72		90
		91	This recipe is simply a comma-separated list of C<address:port> pairs (for
		92	TCP/IP, other protocols might look different).
		93
		94	Node references come in two flavours: resolved (containing only numerical
		95	addresses) or unresolved (where hostnames are used instead of addresses).
		96
		97	Before using an unresolved node reference in a message you first have to
		98	resolve it.
		99
73	=back	100	=back
74		101
75	=head1 VARIABLES/FUNCTIONS	102	=head1 VARIABLES/FUNCTIONS
76		103
77	=over 4	104	=over 4
…		…
88		115
89	use AE ();	116	use AE ();
90		117
91	use base "Exporter";	118	use base "Exporter";
92		119
93	our $VERSION = '0.02';	120	our $VERSION = '0.1';
94	our @EXPORT = qw(	121	our @EXPORT = qw(
95	NODE $NODE *SELF node_of _any_	122	NODE $NODE *SELF node_of _any_
96	become_slave become_public	123	resolve_node initialise_node
97	snd rcv mon kil reg psub	124	snd rcv mon kil reg psub spawn
98	port	125	port
99	);	126	);
100		127
101	our $SELF;	128	our $SELF;
102		129
…		…
111	The C<NODE> function returns, and the C<$NODE> variable contains	138	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	139	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	140	to C<become_public> or C<become_slave>, after which all local port
114	identifiers become invalid.	141	identifiers become invalid.
115		142
116	=item $noderef = node_of $portid	143	=item $noderef = node_of $port
117		144
118	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";
		210
		211	=item $cv = resolve_node $noderef
		212
		213	Takes an unresolved node reference that may contain hostnames and
		214	abbreviated IDs, resolves all of them and returns a resolved node
		215	reference.
		216
		217	In addition to C<address:port> pairs allowed in resolved noderefs, the
		218	following forms are supported:
		219
		220	=over 4
		221
		222	=item the empty string
		223
		224	An empty-string component gets resolved as if the default port (4040) was
		225	specified.
		226
		227	=item naked port numbers (e.g. C<1234>)
		228
		229	These are resolved by prepending the local nodename and a colon, to be
		230	further resolved.
		231
		232	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		233
		234	These are resolved by using AnyEvent::DNS to resolve them, optionally
		235	looking up SRV records for the C<aemp=4040> port, if no port was
		236	specified.
		237
		238	=back
119		239
120	=item $SELF	240	=item $SELF
121		241
122	Contains the current port id while executing C<rcv> callbacks or C<psub>	242	Contains the current port id while executing C<rcv> callbacks or C<psub>
123	blocks.	243	blocks.
…		…
126		246
127	Due to some quirks in how perl exports variables, it is impossible to	247	Due to some quirks in how perl exports variables, it is impossible to
128	just export C<$SELF>, all the symbols called C<SELF> are exported by this	248	just export C<$SELF>, all the symbols called C<SELF> are exported by this
129	module, but only C<$SELF> is currently used.	249	module, but only C<$SELF> is currently used.
130		250
131	=item snd $portid, type => @data	251	=item snd $port, type => @data
132		252
133	=item snd $portid, @msg	253	=item snd $port, @msg
134		254
135	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
136	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
137	stringifies a sa port ID (such as a port object :).	257	stringifies a sa port ID (such as a port object :).
138		258
…		…
148	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
149	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
150	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
151	node, anything can be passed.	271	node, anything can be passed.
152		272
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	273	=item $local_port = port
251		274
252	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.
253		278
254	=item $portid = port { my @msg = @_; $finished }	279	=item $port = port { my @msg = @_; $finished }
255		280
256	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
257	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.
258		284
259	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
260	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
261	will be destroyed. Otherwise it will stay alive.	287	will be destroyed. Otherwise it will stay alive.
262		288
263	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
264	be passed to the callback.	290	be passed to the callback.
265		291
266	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:
267		293
268	my $port; $port = miniport {	294	my $port; $port = port {
269	snd $otherport, reply => $port;	295	snd $otherport, reply => $port;
270	};	296	};
271		297
272	=cut	298	=cut
		299
		300	sub rcv($@);
273		301
274	sub port(;&) {	302	sub port(;&) {
275	my $id = "$UNIQ." . $ID++;	303	my $id = "$UNIQ." . $ID++;
276	my $port = "$NODE#$id";	304	my $port = "$NODE#$id";
277		305
278	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) {
279	my $cb = shift;	395	my $cb = shift;
		396	delete $PORT_DATA{$portid};
280	$PORT{$id} = sub {	397	$PORT{$portid} = sub {
281	local $SELF = $port;	398	local $SELF = $port;
282	eval {	399	eval {
283	&$cb	400	&$cb
284	and kil $id;	401	and kil $port;
285	};	402	};
286	_self_die if $@;	403	_self_die if $@;
287	};	404	};
288	} else {	405	} else {
		406	my $self = $PORT_DATA{$portid} \|\|= do {
289	my $self = bless {	407	my $self = bless {
290	id => "$NODE#$id",	408	id => $port,
291	}, "AnyEvent::MP::Port";	409	}, "AnyEvent::MP::Port";
292		410
293	$PORT_DATA{$id} = $self;
294	$PORT{$id} = sub {	411	$PORT{$portid} = sub {
295	local $SELF = $port;	412	local $SELF = $port;
296		413
297	eval {	414	eval {
298	for (@{ $self->{rc0}{$_[0]} }) {	415	for (@{ $self->{rc0}{$_[0]} }) {
299	$_ && &{$_->[0]}	416	$_ && &{$_->[0]}
300	&& undef $_;	417	&& undef $_;
301	}	418	}
302		419
303	for (@{ $self->{rcv}{$_[0]} }) {	420	for (@{ $self->{rcv}{$_[0]} }) {
304	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
305	&& &{$_->[0]}	422	&& &{$_->[0]}
306	&& undef $_;	423	&& undef $_;
307	}	424	}
308		425
309	for (@{ $self->{any} }) {	426	for (@{ $self->{any} }) {
310	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
311	&& &{$_->[0]}	428	&& &{$_->[0]}
312	&& undef $_;	429	&& undef $_;
		430	}
313	}	431	};
		432	_self_die if $@;
314	};	433	};
315	_self_die if $@;	434
		435	$self
316	};	436	};
317	}
318		437
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	438	"AnyEvent::MP::Port" eq ref $self
380	or Carp::croak "$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";
381		440
382	while (@_) {	441	while (@_) {
383	my ($match, $cb) = splice @_, 0, 2;	442	my ($match, $cb) = splice @_, 0, 2;
384		443
385	if (!ref $match) {	444	if (!ref $match) {
386	push @{ $self->{rc0}{$match} }, [$cb];	445	push @{ $self->{rc0}{$match} }, [$cb];
387	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
388	my ($type, @match) = @$match;	447	my ($type, @match) = @$match;
389	@match	448	@match
390	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
391	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
392	} else {	451	} else {
393	push @{ $self->{any} }, [$cb, $match];	452	push @{ $self->{any} }, [$cb, $match];
		453	}
394	}	454	}
395	}	455	}
		456
		457	$port
396	}	458	}
397		459
398	=item $closure = psub { BLOCK }	460	=item $closure = psub { BLOCK }
399		461
400	Remembers C<$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
…		…
431	$res	493	$res
432	}	494	}
433	}	495	}
434	}	496	}
435		497
436	=back	498	=item $guard = mon $port, $cb->(@reason)
437		499
438	=head1 FUNCTIONS FOR NODES	500	=item $guard = mon $port, $rcvport
439		501
440	=over 4	502	=item $guard = mon $port
441		503
442	=item become_public endpoint...	504	=item $guard = mon $port, $rcvport, @msg
443		505
444	Tells the node to become a public node, i.e. reachable from other nodes.	506	Monitor the given port and do something when the port is killed, and
		507	optionally return a guard that can be used to stop monitoring again.
445		508
446	If no arguments are given, or the first argument is C<undef>, then	509	In the first form (callback), the callback is simply called with any
447	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	510	number of C<@reason> elements (no @reason means that the port was deleted
448	local nodename resolves to.	511	"normally"). Note also that I<< the callback B<must> never die >>, so use
		512	C<eval> if unsure.
449		513
450	Otherwise the first argument must be an array-reference with transport	514	In the second form (another port given), the other port (C<$rcvport)
451	endpoints ("ip:port", "hostname:port") or port numbers (in which case the	515	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
452	local nodename is used as hostname). The endpoints are all resolved and	516	"normal" kils nothing happens, while under all other conditions, the other
453	will become the node reference.	517	port is killed with the same reason.
454		518
		519	The third form (kill self) is the same as the second form, except that
		520	C<$rvport> defaults to C<$SELF>.
		521
		522	In the last form (message), a message of the form C<@msg, @reason> will be
		523	C<snd>.
		524
		525	As a rule of thumb, monitoring requests should always monitor a port from
		526	a local port (or callback). The reason is that kill messages might get
		527	lost, just like any other message. Another less obvious reason is that
		528	even monitoring requests can get lost (for exmaple, when the connection
		529	to the other node goes down permanently). When monitoring a port locally
		530	these problems do not exist.
		531
		532	Example: call a given callback when C<$port> is killed.
		533
		534	mon $port, sub { warn "port died because of <@_>\n" };
		535
		536	Example: kill ourselves when C<$port> is killed abnormally.
		537
		538	mon $port;
		539
		540	Example: send us a restart message when another C<$port> is killed.
		541
		542	mon $port, $self => "restart";
		543
455	=cut	544	=cut
		545
		546	sub mon {
		547	my ($noderef, $port) = split /#/, shift, 2;
		548
		549	my $node = $NODE{$noderef} \|\| add_node $noderef;
		550
		551	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
		552
		553	unless (ref $cb) {
		554	if (@_) {
		555	# send a kill info message
		556	my (@msg) = @_;
		557	$cb = sub { snd @msg, @_ };
		558	} else {
		559	# simply kill other port
		560	my $port = $cb;
		561	$cb = sub { kil $port, @_ if @_ };
		562	}
		563	}
		564
		565	$node->monitor ($port, $cb);
		566
		567	defined wantarray
		568	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		569	}
		570
		571	=item $guard = mon_guard $port, $ref, $ref...
		572
		573	Monitors the given C<$port> and keeps the passed references. When the port
		574	is killed, the references will be freed.
		575
		576	Optionally returns a guard that will stop the monitoring.
		577
		578	This function is useful when you create e.g. timers or other watchers and
		579	want to free them when the port gets killed:
		580
		581	$port->rcv (start => sub {
		582	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		583	undef $timer if 0.9 < rand;
		584	});
		585	});
		586
		587	=cut
		588
		589	sub mon_guard {
		590	my ($port, @refs) = @_;
		591
		592	#TODO: mon-less form?
		593
		594	mon $port, sub { 0 && @refs }
		595	}
		596
		597	=item kil $port[, @reason]
		598
		599	Kill the specified port with the given C<@reason>.
		600
		601	If no C<@reason> is specified, then the port is killed "normally" (linked
		602	ports will not be kileld, or even notified).
		603
		604	Otherwise, linked ports get killed with the same reason (second form of
		605	C<mon>, see below).
		606
		607	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		608	will be reported as reason C<< die => $@ >>.
		609
		610	Transport/communication errors are reported as C<< transport_error =>
		611	$message >>.
		612
		613	=cut
		614
		615	=item $port = spawn $node, $initfunc[, @initdata]
		616
		617	Creates a port on the node C<$node> (which can also be a port ID, in which
		618	case it's the node where that port resides).
		619
		620	The port ID of the newly created port is return immediately, and it is
		621	permissible to immediately start sending messages or monitor the port.
		622
		623	After the port has been created, the init function is
		624	called. This function must be a fully-qualified function name
		625	(e.g. C<MyApp::Chat::Server::init>).
		626
		627	If the function doesn't exist, then the node tries to C<require>
		628	the package, then the package above the package and so on (e.g.
		629	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		630	exists or it runs out of package names.
		631
		632	The init function is then called with the newly-created port as context
		633	object (C<$SELF>) and the C<@initdata> values as arguments.
		634
		635	A common idiom is to pass your own port, monitor the spawned port, and
		636	in the init function, monitor the original port. This two-way monitoring
		637	ensures that both ports get cleaned up when there is a problem.
		638
		639	Example: spawn a chat server port on C<$othernode>.
		640
		641	# this node, executed from within a port context:
		642	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		643	mon $server;
		644
		645	# init function on C<$othernode>
		646	sub connect {
		647	my ($srcport) = @_;
		648
		649	mon $srcport;
		650
		651	rcv $SELF, sub {
		652	...
		653	};
		654	}
		655
		656	=cut
		657
		658	sub _spawn {
		659	my $port = shift;
		660	my $init = shift;
		661
		662	local $SELF = "$NODE#$port";
		663	eval {
		664	&{ load_func $init }
		665	};
		666	_self_die if $@;
		667	}
		668
		669	sub spawn(@) {
		670	my ($noderef, undef) = split /#/, shift, 2;
		671
		672	my $id = "$RUNIQ." . $ID++;
		673
		674	$_[0] =~ /::/
		675	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		676
		677	($NODE{$noderef} \|\| add_node $noderef)
		678	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		679
		680	"$noderef#$id"
		681	}
456		682
457	=back	683	=back
458		684
459	=head1 NODE MESSAGES	685	=head1 NODE MESSAGES
460		686
461	Nodes understand the following messages sent to them. Many of them take	687	Nodes understand the following messages sent to them. Many of them take
462	arguments called C<@reply>, which will simply be used to compose a reply	688	arguments called C<@reply>, which will simply be used to compose a reply
463	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	689	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
464	the remaining arguments are simply the message data.	690	the remaining arguments are simply the message data.
465		691
		692	While other messages exist, they are not public and subject to change.
		693
466	=over 4	694	=over 4
467		695
468	=cut	696	=cut
469		697
470	=item lookup => $name, @reply	698	=item lookup => $name, @reply
…		…
498	snd $NODE, time => $myport, timereply => 1, 2;	726	snd $NODE, time => $myport, timereply => 1, 2;
499	# => snd $myport, timereply => 1, 2, <time>	727	# => snd $myport, timereply => 1, 2, <time>
500		728
501	=back	729	=back
502		730
		731	=head1 AnyEvent::MP vs. Distributed Erlang
		732
		733	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
		734	== aemp node, Erlang process == aemp port), so many of the documents and
		735	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		736	sample:
		737
		738	http://www.Erlang.se/doc/programming_rules.shtml
		739	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		740	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		741	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		742
		743	Despite the similarities, there are also some important differences:
		744
		745	=over 4
		746
		747	=item * Node references contain the recipe on how to contact them.
		748
		749	Erlang relies on special naming and DNS to work everywhere in the
		750	same way. AEMP relies on each node knowing it's own address(es), with
		751	convenience functionality.
		752
		753	This means that AEMP requires a less tightly controlled environment at the
		754	cost of longer node references and a slightly higher management overhead.
		755
		756	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		757
		758	Erlang uses processes that selctively receive messages, and therefore
		759	needs a queue. AEMP is event based, queuing messages would serve no useful
		760	purpose.
		761
		762	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
		763
		764	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		765
		766	Sending messages in Erlang is synchronous and blocks the process. AEMP
		767	sends are immediate, connection establishment is handled in the
		768	background.
		769
		770	=item * Erlang can silently lose messages, AEMP cannot.
		771
		772	Erlang makes few guarantees on messages delivery - messages can get lost
		773	without any of the processes realising it (i.e. you send messages a, b,
		774	and c, and the other side only receives messages a and c).
		775
		776	AEMP guarantees correct ordering, and the guarantee that there are no
		777	holes in the message sequence.
		778
		779	=item * In Erlang, processes can be declared dead and later be found to be
		780	alive.
		781
		782	In Erlang it can happen that a monitored process is declared dead and
		783	linked processes get killed, but later it turns out that the process is
		784	still alive - and can receive messages.
		785
		786	In AEMP, when port monitoring detects a port as dead, then that port will
		787	eventually be killed - it cannot happen that a node detects a port as dead
		788	and then later sends messages to it, finding it is still alive.
		789
		790	=item * Erlang can send messages to the wrong port, AEMP does not.
		791
		792	In Erlang it is quite possible that a node that restarts reuses a process
		793	ID known to other nodes for a completely different process, causing
		794	messages destined for that process to end up in an unrelated process.
		795
		796	AEMP never reuses port IDs, so old messages or old port IDs floating
		797	around in the network will not be sent to an unrelated port.
		798
		799	=item * Erlang uses unprotected connections, AEMP uses secure
		800	authentication and can use TLS.
		801
		802	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		803	securely authenticate nodes.
		804
		805	=item * The AEMP protocol is optimised for both text-based and binary
		806	communications.
		807
		808	The AEMP protocol, unlike the Erlang protocol, supports both
		809	language-independent text-only protocols (good for debugging) and binary,
		810	language-specific serialisers (e.g. Storable).
		811
		812	It has also been carefully designed to be implementable in other languages
		813	with a minimum of work while gracefully degrading fucntionality to make the
		814	protocol simple.
		815
		816	=item * AEMP has more flexible monitoring options than Erlang.
		817
		818	In Erlang, you can chose to receive I<all> exit signals as messages
		819	or I<none>, there is no in-between, so monitoring single processes is
		820	difficult to implement. Monitoring in AEMP is more flexible than in
		821	Erlang, as one can choose between automatic kill, exit message or callback
		822	on a per-process basis.
		823
		824	=item * Erlang tries to hide remote/local connections, AEMP does not.
		825
		826	Monitoring in Erlang is not an indicator of process death/crashes,
		827	as linking is (except linking is unreliable in Erlang).
		828
		829	In AEMP, you don't "look up" registered port names or send to named ports
		830	that might or might not be persistent. Instead, you normally spawn a port
		831	on the remote node. The init function monitors the you, and you monitor
		832	the remote port. Since both monitors are local to the node, they are much
		833	more reliable.
		834
		835	This also saves round-trips and avoids sending messages to the wrong port
		836	(hard to do in Erlang).
		837
		838	=back
		839
503	=head1 SEE ALSO	840	=head1 SEE ALSO
504		841
505	L<AnyEvent>.	842	L<AnyEvent>.
506		843
507	=head1 AUTHOR	844	=head1 AUTHOR

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.23 by root, Tue Aug 4 18:46:16 2009 UTC vs. Revision 1.39 by root, Fri Aug 7 23:21:48 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.23 by root, Tue Aug 4 18:46:16 2009 UTC vs.
Revision 1.39 by root, Fri Aug 7 23:21:48 2009 UTC