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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.27 by root, Tue Aug 4 22:13:45 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
…		…
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).
		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.
72		99
73	=back	100	=back
74		101
75	=head1 VARIABLES/FUNCTIONS	102	=head1 VARIABLES/FUNCTIONS
76		103
…		…
91	use base "Exporter";	118	use base "Exporter";
92		119
93	our $VERSION = '0.1';	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 lnk $port1, $port2
251
252	Link two ports. This is simply a shorthand for:
253
254	mon $port1, $port2;
255	mon $port2, $port1;
256
257	It means that if either one is killed abnormally, the other one gets
258	killed as well.
259
260	=item $local_port = port	273	=item $local_port = port
261		274
262	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.
263		278
264	=item $portid = port { my @msg = @_; $finished }	279	=item $port = port { my @msg = @_; $finished }
265		280
266	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
267	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.
268		284
269	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
270	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
271	will be destroyed. Otherwise it will stay alive.	287	will be destroyed. Otherwise it will stay alive.
272		288
273	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
274	be passed to the callback.	290	be passed to the callback.
275		291
276	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:
277		293
278	my $port; $port = miniport {	294	my $port; $port = port {
279	snd $otherport, reply => $port;	295	snd $otherport, reply => $port;
280	};	296	};
281		297
282	=cut	298	=cut
		299
		300	sub rcv($@);
283		301
284	sub port(;&) {	302	sub port(;&) {
285	my $id = "$UNIQ." . $ID++;	303	my $id = "$UNIQ." . $ID++;
286	my $port = "$NODE#$id";	304	my $port = "$NODE#$id";
287		305
288	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) {
289	my $cb = shift;	395	my $cb = shift;
		396	delete $PORT_DATA{$portid};
290	$PORT{$id} = sub {	397	$PORT{$portid} = sub {
291	local $SELF = $port;	398	local $SELF = $port;
292	eval {	399	eval {
293	&$cb	400	&$cb
294	and kil $id;	401	and kil $port;
295	};	402	};
296	_self_die if $@;	403	_self_die if $@;
297	};	404	};
298	} else {	405	} else {
		406	my $self = $PORT_DATA{$portid} \|\|= do {
299	my $self = bless {	407	my $self = bless {
300	id => "$NODE#$id",	408	id => $port,
301	}, "AnyEvent::MP::Port";	409	}, "AnyEvent::MP::Port";
302		410
303	$PORT_DATA{$id} = $self;
304	$PORT{$id} = sub {	411	$PORT{$portid} = sub {
305	local $SELF = $port;	412	local $SELF = $port;
306		413
307	eval {	414	eval {
308	for (@{ $self->{rc0}{$_[0]} }) {	415	for (@{ $self->{rc0}{$_[0]} }) {
309	$_ && &{$_->[0]}	416	$_ && &{$_->[0]}
310	&& undef $_;	417	&& undef $_;
311	}	418	}
312		419
313	for (@{ $self->{rcv}{$_[0]} }) {	420	for (@{ $self->{rcv}{$_[0]} }) {
314	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
315	&& &{$_->[0]}	422	&& &{$_->[0]}
316	&& undef $_;	423	&& undef $_;
317	}	424	}
318		425
319	for (@{ $self->{any} }) {	426	for (@{ $self->{any} }) {
320	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
321	&& &{$_->[0]}	428	&& &{$_->[0]}
322	&& undef $_;	429	&& undef $_;
		430	}
323	}	431	};
		432	_self_die if $@;
324	};	433	};
325	_self_die if $@;	434
		435	$self
326	};	436	};
327	}
328		437
329	$port
330	}
331
332	=item reg $portid, $name
333
334	Registers the given port under the name C<$name>. If the name already
335	exists it is replaced.
336
337	A port can only be registered under one well known name.
338
339	A port automatically becomes unregistered when it is killed.
340
341	=cut
342
343	sub reg(@) {
344	my ($portid, $name) = @_;
345
346	$REG{$name} = $portid;
347	}
348
349	=item rcv $portid, tagstring => $callback->(@msg), ...
350
351	=item rcv $portid, $smartmatch => $callback->(@msg), ...
352
353	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
354
355	Register callbacks to be called on matching messages on the given port.
356
357	The callback has to return a true value when its work is done, after
358	which is will be removed, or a false value in which case it will stay
359	registered.
360
361	The global C<$SELF> (exported by this module) contains C<$portid> while
362	executing the callback.
363
364	Runtime errors wdurign callback execution will result in the port being
365	C<kil>ed.
366
367	If the match is an array reference, then it will be matched against the
368	first elements of the message, otherwise only the first element is being
369	matched.
370
371	Any element in the match that is specified as C<_any_> (a function
372	exported by this module) matches any single element of the message.
373
374	While not required, it is highly recommended that the first matching
375	element is a string identifying the message. The one-string-only match is
376	also the most efficient match (by far).
377
378	=cut
379
380	sub rcv($@) {
381	my ($noderef, $port) = split /#/, shift, 2;
382
383	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
384	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
385
386	my $self = $PORT_DATA{$port}
387	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
388
389	"AnyEvent::MP::Port" eq ref $self	438	"AnyEvent::MP::Port" eq ref $self
390	or Carp::croak "$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";
391		440
392	while (@_) {	441	while (@_) {
393	my ($match, $cb) = splice @_, 0, 2;	442	my ($match, $cb) = splice @_, 0, 2;
394		443
395	if (!ref $match) {	444	if (!ref $match) {
396	push @{ $self->{rc0}{$match} }, [$cb];	445	push @{ $self->{rc0}{$match} }, [$cb];
397	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
398	my ($type, @match) = @$match;	447	my ($type, @match) = @$match;
399	@match	448	@match
400	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
401	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
402	} else {	451	} else {
403	push @{ $self->{any} }, [$cb, $match];	452	push @{ $self->{any} }, [$cb, $match];
		453	}
404	}	454	}
405	}	455	}
		456
		457	$port
406	}	458	}
407		459
408	=item $closure = psub { BLOCK }	460	=item $closure = psub { BLOCK }
409		461
410	Remembers C<$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
…		…
441	$res	493	$res
442	}	494	}
443	}	495	}
444	}	496	}
445		497
446	=back	498	=item $guard = mon $port, $cb->(@reason)
447		499
448	=head1 FUNCTIONS FOR NODES	500	=item $guard = mon $port, $rcvport
449		501
450	=over 4	502	=item $guard = mon $port
451		503
452	=item become_public endpoint...	504	=item $guard = mon $port, $rcvport, @msg
453		505
454	Tells the node to become a public node, i.e. reachable from other nodes.	506	Monitor the given port and do something when the port is killed or
		507	messages to it were lost, and optionally return a guard that can be used
		508	to stop monitoring again.
455		509
456	If no arguments are given, or the first argument is C<undef>, then	510	C<mon> effectively guarantees that, in the absence of hardware failures,
457	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	511	that after starting the monitor, either all messages sent to the port
458	local nodename resolves to.	512	will arrive, or the monitoring action will be invoked after possible
		513	message loss has been detected. No messages will be lost "in between"
		514	(after the first lost message no further messages will be received by the
		515	port). After the monitoring action was invoked, further messages might get
		516	delivered again.
459		517
460	Otherwise the first argument must be an array-reference with transport	518	In the first form (callback), the callback is simply called with any
461	endpoints ("ip:port", "hostname:port") or port numbers (in which case the	519	number of C<@reason> elements (no @reason means that the port was deleted
462	local nodename is used as hostname). The endpoints are all resolved and	520	"normally"). Note also that I<< the callback B<must> never die >>, so use
463	will become the node reference.	521	C<eval> if unsure.
464		522
		523	In the second form (another port given), the other port (C<$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, $self => "restart";
		552
465	=cut	553	=cut
		554
		555	sub mon {
		556	my ($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#$id"
		691	}
466		692
467	=back	693	=back
468		694
469	=head1 NODE MESSAGES	695	=head1 NODE MESSAGES
470		696
471	Nodes understand the following messages sent to them. Many of them take	697	Nodes understand the following messages sent to them. Many of them take
472	arguments called C<@reply>, which will simply be used to compose a reply	698	arguments called C<@reply>, which will simply be used to compose a reply
473	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	699	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
474	the remaining arguments are simply the message data.	700	the remaining arguments are simply the message data.
475		701
		702	While other messages exist, they are not public and subject to change.
		703
476	=over 4	704	=over 4
477		705
478	=cut	706	=cut
479		707
480	=item lookup => $name, @reply	708	=item lookup => $name, @reply
…		…
510		738
511	=back	739	=back
512		740
513	=head1 AnyEvent::MP vs. Distributed Erlang	741	=head1 AnyEvent::MP vs. Distributed Erlang
514		742
515	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
516	== 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
517	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
518	sample:	746	sample:
519		747
520	http://www.erlang.se/doc/programming_rules.shtml	748	http://www.Erlang.se/doc/programming_rules.shtml
521	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
522	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
523	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
524		752
525	Despite the similarities, there are also some important differences:	753	Despite the similarities, there are also some important differences:
526		754
527	=over 4	755	=over 4
528		756
…		…
539		767
540	Erlang uses processes that selctively receive messages, and therefore	768	Erlang uses processes that selctively receive messages, and therefore
541	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
542	purpose.	770	purpose.
543		771
544	(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).
545		773
546	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	774	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
547		775
548	Sending messages in erlang is synchronous and blocks the process. AEMP	776	Sending messages in Erlang is synchronous and blocks the process. AEMP
549	sends are immediate, connection establishment is handled in the	777	sends are immediate, connection establishment is handled in the
550	background.	778	background.
551		779
552	=item * Erlang can silently lose messages, AEMP cannot.	780	=item * Erlang can silently lose messages, AEMP cannot.
553		781
…		…
556	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).
557		785
558	AEMP guarantees correct ordering, and the guarantee that there are no	786	AEMP guarantees correct ordering, and the guarantee that there are no
559	holes in the message sequence.	787	holes in the message sequence.
560		788
561	=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
562	alive.	790	alive.
563		791
564	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
565	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
566	still alive - and can receive messages.	794	still alive - and can receive messages.
567		795
568	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
569	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
570	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.
571		799
572	=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.
573		801
574	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
575	ID known to other nodes for a completely different process, causing	803	ID known to other nodes for a completely different process, causing
576	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.
577		805
578	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
579	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.
…		…
582	authentication and can use TLS.	810	authentication and can use TLS.
583		811
584	AEMP can use a proven protocol - SSL/TLS - to protect connections and	812	AEMP can use a proven protocol - SSL/TLS - to protect connections and
585	securely authenticate nodes.	813	securely authenticate nodes.
586		814
		815	=item * The AEMP protocol is optimised for both text-based and binary
		816	communications.
		817
		818	The AEMP protocol, unlike the Erlang protocol, supports both
		819	language-independent text-only protocols (good for debugging) and binary,
		820	language-specific serialisers (e.g. Storable).
		821
		822	It has also been carefully designed to be implementable in other languages
		823	with a minimum of work while gracefully degrading fucntionality to make the
		824	protocol simple.
		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
587	=back	848	=back
588		849
589	=head1 SEE ALSO	850	=head1 SEE ALSO
590		851
591	L<AnyEvent>.	852	L<AnyEvent>.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.27 by root, Tue Aug 4 22:13:45 2009 UTC vs. Revision 1.42 by root, Sun Aug 9 00:41:49 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.27 by root, Tue Aug 4 22:13:45 2009 UTC vs.
Revision 1.42 by root, Sun Aug 9 00:41:49 2009 UTC