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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.22 by root, Tue Aug 4 18:33:30 2009 UTC vs.
Revision 1.38 by root, Fri Aug 7 22:55:18 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
33	on the same or other hosts.	48	on the same or other hosts.
34		49
		50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		51	manual page.
		52
35	At the moment, this module family is severly brokena nd underdocumented,	53	At the moment, this module family is severly broken and underdocumented,
36	so do not use. This was uploaded mainly to reserve the CPAN namespace -	54	so do not use. This was uploaded mainly to reserve the CPAN namespace -
37	stay tuned!	55	stay tuned! The basic API should be finished, however.
38		56
39	=head1 CONCEPTS	57	=head1 CONCEPTS
40		58
41	=over 4	59	=over 4
42		60
43	=item port	61	=item port
44		62
45	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).
46	you can register C<rcv> handlers with. All C<rcv> handlers will receive	64
47	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.
48		68
49	=item port id - C<noderef#portname>	69	=item port id - C<noderef#portname>
50		70
51	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
52	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.
53		75
54	=item node	76	=item node
55		77
56	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
57	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
58	among other things.	80	create new ports, among other things.
59		81
60	Initially, nodes are either private (single-process only) or hidden	82	Nodes are either private (single-process only), slaves (connected to a
61	(connected to a master node only). Only when they epxlicitly "become	83	master node only) or public nodes (connectable from unrelated nodes).
62	public" can you send them messages from unrelated other nodes.
63		84
64	=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>
65		86
66	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
67	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
68	node (for public nodes).	89	node (for public nodes).
69		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
70	=back	100	=back
71		101
72	=head1 VARIABLES/FUNCTIONS	102	=head1 VARIABLES/FUNCTIONS
73		103
74	=over 4	104	=over 4
…		…
85		115
86	use AE ();	116	use AE ();
87		117
88	use base "Exporter";	118	use base "Exporter";
89		119
90	our $VERSION = '0.02';	120	our $VERSION = '0.1';
91	our @EXPORT = qw(	121	our @EXPORT = qw(
92	NODE $NODE *SELF node_of _any_	122	NODE $NODE *SELF node_of _any_
93	become_slave become_public	123	resolve_node initialise_node
94	snd rcv mon kil reg psub	124	snd rcv mon kil reg psub spawn
95	port	125	port
96	);	126	);
97		127
98	our $SELF;	128	our $SELF;
99		129
…		…
108	The C<NODE> function returns, and the C<$NODE> variable contains	138	The C<NODE> function returns, and the C<$NODE> variable contains
109	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
110	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
111	identifiers become invalid.	141	identifiers become invalid.
112		142
113	=item $noderef = node_of $portid	143	=item $noderef = node_of $port
114		144
115	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
116		239
117	=item $SELF	240	=item $SELF
118		241
119	Contains the current port id while executing C<rcv> callbacks or C<psub>	242	Contains the current port id while executing C<rcv> callbacks or C<psub>
120	blocks.	243	blocks.
…		…
123		246
124	Due to some quirks in how perl exports variables, it is impossible to	247	Due to some quirks in how perl exports variables, it is impossible to
125	just export C<$SELF>, all the symbols called C<SELF> are exported by this	248	just export C<$SELF>, all the symbols called C<SELF> are exported by this
126	module, but only C<$SELF> is currently used.	249	module, but only C<$SELF> is currently used.
127		250
128	=item snd $portid, type => @data	251	=item snd $port, type => @data
129		252
130	=item snd $portid, @msg	253	=item snd $port, @msg
131		254
132	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
133	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
134	stringifies a sa port ID (such as a port object :).	257	stringifies a sa port ID (such as a port object :).
135		258
…		…
145	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
146	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
147	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
148	node, anything can be passed.	271	node, anything can be passed.
149		272
150	=item kil $portid[, @reason]
151
152	Kill the specified port with the given C<@reason>.
153
154	If no C<@reason> is specified, then the port is killed "normally" (linked
155	ports will not be kileld, or even notified).
156
157	Otherwise, linked ports get killed with the same reason (second form of
158	C<mon>, see below).
159
160	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
161	will be reported as reason C<< die => $@ >>.
162
163	Transport/communication errors are reported as C<< transport_error =>
164	$message >>.
165
166	=item $guard = mon $portid, $cb->(@reason)
167
168	=item $guard = mon $portid, $otherport
169
170	=item $guard = mon $portid, $otherport, @msg
171
172	Monitor the given port and do something when the port is killed.
173
174	In the first form, the callback is simply called with any number
175	of C<@reason> elements (no @reason means that the port was deleted
176	"normally"). Note also that I<< the callback B<must> never die >>, so use
177	C<eval> if unsure.
178
179	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
180	a @reason was specified, i.e. on "normal" kils nothing happens, while
181	under all other conditions, the other port is killed with the same reason.
182
183	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
184
185	Example: call a given callback when C<$port> is killed.
186
187	mon $port, sub { warn "port died because of <@_>\n" };
188
189	Example: kill ourselves when C<$port> is killed abnormally.
190
191	mon $port, $self;
192
193	Example: send us a restart message another C<$port> is killed.
194
195	mon $port, $self => "restart";
196
197	=cut
198
199	sub mon {
200	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
201
202	my $node = $NODE{$noderef} \|\| add_node $noderef;
203
204	#TODO: ports must not be references
205	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
206	if (@_) {
207	# send a kill info message
208	my (@msg) = ($cb, @_);
209	$cb = sub { snd @msg, @_ };
210	} else {
211	# simply kill other port
212	my $port = $cb;
213	$cb = sub { kil $port, @_ if @_ };
214	}
215	}
216
217	$node->monitor ($port, $cb);
218
219	defined wantarray
220	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
221	}
222
223	=item $guard = mon_guard $port, $ref, $ref...
224
225	Monitors the given C<$port> and keeps the passed references. When the port
226	is killed, the references will be freed.
227
228	Optionally returns a guard that will stop the monitoring.
229
230	This function is useful when you create e.g. timers or other watchers and
231	want to free them when the port gets killed:
232
233	$port->rcv (start => sub {
234	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
235	undef $timer if 0.9 < rand;
236	});
237	});
238
239	=cut
240
241	sub mon_guard {
242	my ($port, @refs) = @_;
243
244	mon $port, sub { 0 && @refs }
245	}
246
247	=item $local_port = port	273	=item $local_port = port
248		274
249	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.
250		278
251	=item $portid = port { my @msg = @_; $finished }	279	=item $port = port { my @msg = @_; $finished }
252		280
253	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
254	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.
255		284
256	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
257	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
258	will be destroyed. Otherwise it will stay alive.	287	will be destroyed. Otherwise it will stay alive.
259		288
260	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
261	be passed to the callback.	290	be passed to the callback.
262		291
263	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:
264		293
265	my $port; $port = miniport {	294	my $port; $port = port {
266	snd $otherport, reply => $port;	295	snd $otherport, reply => $port;
267	};	296	};
268		297
269	=cut	298	=cut
		299
		300	sub rcv($@);
270		301
271	sub port(;&) {	302	sub port(;&) {
272	my $id = "$UNIQ." . $ID++;	303	my $id = "$UNIQ." . $ID++;
273	my $port = "$NODE#$id";	304	my $port = "$NODE#$id";
274		305
275	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) {
276	my $cb = shift;	395	my $cb = shift;
		396	delete $PORT_DATA{$portid};
277	$PORT{$id} = sub {	397	$PORT{$portid} = sub {
278	local $SELF = $port;	398	local $SELF = $port;
279	eval {	399	eval {
280	&$cb	400	&$cb
281	and kil $id;	401	and kil $port;
282	};	402	};
283	_self_die if $@;	403	_self_die if $@;
284	};	404	};
285	} else {	405	} else {
		406	my $self = $PORT_DATA{$portid} \|\|= do {
286	my $self = bless {	407	my $self = bless {
287	id => "$NODE#$id",	408	id => $port,
288	}, "AnyEvent::MP::Port";	409	}, "AnyEvent::MP::Port";
289		410
290	$PORT_DATA{$id} = $self;
291	$PORT{$id} = sub {	411	$PORT{$portid} = sub {
292	local $SELF = $port;	412	local $SELF = $port;
293		413
294	eval {	414	eval {
295	for (@{ $self->{rc0}{$_[0]} }) {	415	for (@{ $self->{rc0}{$_[0]} }) {
296	$_ && &{$_->[0]}	416	$_ && &{$_->[0]}
297	&& undef $_;	417	&& undef $_;
298	}	418	}
299		419
300	for (@{ $self->{rcv}{$_[0]} }) {	420	for (@{ $self->{rcv}{$_[0]} }) {
301	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
302	&& &{$_->[0]}	422	&& &{$_->[0]}
303	&& undef $_;	423	&& undef $_;
304	}	424	}
305		425
306	for (@{ $self->{any} }) {	426	for (@{ $self->{any} }) {
307	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
308	&& &{$_->[0]}	428	&& &{$_->[0]}
309	&& undef $_;	429	&& undef $_;
		430	}
310	}	431	};
		432	_self_die if $@;
311	};	433	};
312	_self_die if $@;	434
		435	$self
313	};	436	};
314	}
315		437
316	$port
317	}
318
319	=item reg $portid, $name
320
321	Registers the given port under the name C<$name>. If the name already
322	exists it is replaced.
323
324	A port can only be registered under one well known name.
325
326	A port automatically becomes unregistered when it is killed.
327
328	=cut
329
330	sub reg(@) {
331	my ($portid, $name) = @_;
332
333	$REG{$name} = $portid;
334	}
335
336	=item rcv $portid, tagstring => $callback->(@msg), ...
337
338	=item rcv $portid, $smartmatch => $callback->(@msg), ...
339
340	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
341
342	Register callbacks to be called on matching messages on the given port.
343
344	The callback has to return a true value when its work is done, after
345	which is will be removed, or a false value in which case it will stay
346	registered.
347
348	The global C<$SELF> (exported by this module) contains C<$portid> while
349	executing the callback.
350
351	Runtime errors wdurign callback execution will result in the port being
352	C<kil>ed.
353
354	If the match is an array reference, then it will be matched against the
355	first elements of the message, otherwise only the first element is being
356	matched.
357
358	Any element in the match that is specified as C<_any_> (a function
359	exported by this module) matches any single element of the message.
360
361	While not required, it is highly recommended that the first matching
362	element is a string identifying the message. The one-string-only match is
363	also the most efficient match (by far).
364
365	=cut
366
367	sub rcv($@) {
368	my ($noderef, $port) = split /#/, shift, 2;
369
370	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
371	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
372
373	my $self = $PORT_DATA{$port}
374	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
375
376	"AnyEvent::MP::Port" eq ref $self	438	"AnyEvent::MP::Port" eq ref $self
377	or Carp::croak "$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";
378		440
379	while (@_) {	441	while (@_) {
380	my ($match, $cb) = splice @_, 0, 2;	442	my ($match, $cb) = splice @_, 0, 2;
381		443
382	if (!ref $match) {	444	if (!ref $match) {
383	push @{ $self->{rc0}{$match} }, [$cb];	445	push @{ $self->{rc0}{$match} }, [$cb];
384	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
385	my ($type, @match) = @$match;	447	my ($type, @match) = @$match;
386	@match	448	@match
387	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
388	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
389	} else {	451	} else {
390	push @{ $self->{any} }, [$cb, $match];	452	push @{ $self->{any} }, [$cb, $match];
		453	}
391	}	454	}
392	}	455	}
		456
		457	$port
393	}	458	}
394		459
395	=item $closure = psub { BLOCK }	460	=item $closure = psub { BLOCK }
396		461
397	Remembers C<$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
…		…
428	$res	493	$res
429	}	494	}
430	}	495	}
431	}	496	}
432		497
433	=back	498	=item $guard = mon $port, $cb->(@reason)
434		499
435	=head1 FUNCTIONS FOR NODES	500	=item $guard = mon $port, $rcvport
436		501
437	=over 4	502	=item $guard = mon $port
438		503
439	=item become_public endpoint...	504	=item $guard = mon $port, $rcvport, @msg
440		505
441	Tells the node to become a public node, i.e. reachable from other nodes.	506	Monitor the given port and do something when the port is killed, and
		507	optionally return a guard that can be used to stop monitoring again.
442		508
443	If no arguments are given, or the first argument is C<undef>, then	509	In the first form (callback), the callback is simply called with any
444	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	510	number of C<@reason> elements (no @reason means that the port was deleted
445	local nodename resolves to.	511	"normally"). Note also that I<< the callback B<must> never die >>, so use
		512	C<eval> if unsure.
446		513
447	Otherwise the first argument must be an array-reference with transport	514	In the second form (another port given), the other port (C<$rcvport)
448	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
449	local nodename is used as hostname). The endpoints are all resolved and	516	"normal" kils nothing happens, while under all other conditions, the other
450	will become the node reference.	517	port is killed with the same reason.
451		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, $self => "restart";
		543
452	=cut	544	=cut
		545
		546	sub mon {
		547	my ($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 fucntion 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." . $ID++;
		673
		674	($NODE{$noderef} \|\| add_node $noderef)
		675	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		676
		677	"$noderef#$id"
		678	}
453		679
454	=back	680	=back
455		681
456	=head1 NODE MESSAGES	682	=head1 NODE MESSAGES
457		683
458	Nodes understand the following messages sent to them. Many of them take	684	Nodes understand the following messages sent to them. Many of them take
459	arguments called C<@reply>, which will simply be used to compose a reply	685	arguments called C<@reply>, which will simply be used to compose a reply
460	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	686	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
461	the remaining arguments are simply the message data.	687	the remaining arguments are simply the message data.
462		688
		689	While other messages exist, they are not public and subject to change.
		690
463	=over 4	691	=over 4
464		692
465	=cut	693	=cut
466		694
467	=item lookup => $name, @reply	695	=item lookup => $name, @reply
…		…
495	snd $NODE, time => $myport, timereply => 1, 2;	723	snd $NODE, time => $myport, timereply => 1, 2;
496	# => snd $myport, timereply => 1, 2, <time>	724	# => snd $myport, timereply => 1, 2, <time>
497		725
498	=back	726	=back
499		727
		728	=head1 AnyEvent::MP vs. Distributed Erlang
		729
		730	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
		731	== aemp node, Erlang process == aemp port), so many of the documents and
		732	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		733	sample:
		734
		735	http://www.Erlang.se/doc/programming_rules.shtml
		736	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		737	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		738	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		739
		740	Despite the similarities, there are also some important differences:
		741
		742	=over 4
		743
		744	=item * Node references contain the recipe on how to contact them.
		745
		746	Erlang relies on special naming and DNS to work everywhere in the
		747	same way. AEMP relies on each node knowing it's own address(es), with
		748	convenience functionality.
		749
		750	This means that AEMP requires a less tightly controlled environment at the
		751	cost of longer node references and a slightly higher management overhead.
		752
		753	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		754
		755	Erlang uses processes that selctively receive messages, and therefore
		756	needs a queue. AEMP is event based, queuing messages would serve no useful
		757	purpose.
		758
		759	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
		760
		761	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		762
		763	Sending messages in Erlang is synchronous and blocks the process. AEMP
		764	sends are immediate, connection establishment is handled in the
		765	background.
		766
		767	=item * Erlang can silently lose messages, AEMP cannot.
		768
		769	Erlang makes few guarantees on messages delivery - messages can get lost
		770	without any of the processes realising it (i.e. you send messages a, b,
		771	and c, and the other side only receives messages a and c).
		772
		773	AEMP guarantees correct ordering, and the guarantee that there are no
		774	holes in the message sequence.
		775
		776	=item * In Erlang, processes can be declared dead and later be found to be
		777	alive.
		778
		779	In Erlang it can happen that a monitored process is declared dead and
		780	linked processes get killed, but later it turns out that the process is
		781	still alive - and can receive messages.
		782
		783	In AEMP, when port monitoring detects a port as dead, then that port will
		784	eventually be killed - it cannot happen that a node detects a port as dead
		785	and then later sends messages to it, finding it is still alive.
		786
		787	=item * Erlang can send messages to the wrong port, AEMP does not.
		788
		789	In Erlang it is quite possible that a node that restarts reuses a process
		790	ID known to other nodes for a completely different process, causing
		791	messages destined for that process to end up in an unrelated process.
		792
		793	AEMP never reuses port IDs, so old messages or old port IDs floating
		794	around in the network will not be sent to an unrelated port.
		795
		796	=item * Erlang uses unprotected connections, AEMP uses secure
		797	authentication and can use TLS.
		798
		799	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		800	securely authenticate nodes.
		801
		802	=item * The AEMP protocol is optimised for both text-based and binary
		803	communications.
		804
		805	The AEMP protocol, unlike the Erlang protocol, supports both
		806	language-independent text-only protocols (good for debugging) and binary,
		807	language-specific serialisers (e.g. Storable).
		808
		809	It has also been carefully designed to be implementable in other languages
		810	with a minimum of work while gracefully degrading fucntionality to make the
		811	protocol simple.
		812
		813	=item * AEMP has more flexible monitoring options than Erlang.
		814
		815	In Erlang, you can chose to receive I<all> exit signals as messages
		816	or I<none>, there is no in-between, so monitoring single processes is
		817	difficult to implement. Monitoring in AEMP is more flexible than in
		818	Erlang, as one can choose between automatic kill, exit message or callback
		819	on a per-process basis.
		820
		821	=item * Erlang tries to hide remote/local connections, AEMP does not.
		822
		823	Monitoring in Erlang is not an indicator of process death/crashes,
		824	as linking is (except linking is unreliable in Erlang).
		825
		826	In AEMP, you don't "look up" registered port names or send to named ports
		827	that might or might not be persistent. Instead, you normally spawn a port
		828	on the remote node. The init function monitors the you, and you monitor
		829	the remote port. Since both monitors are local to the node, they are much
		830	more reliable.
		831
		832	This also saves round-trips and avoids sending messages to the wrong port
		833	(hard to do in Erlang).
		834
		835	=back
		836
500	=head1 SEE ALSO	837	=head1 SEE ALSO
501		838
502	L<AnyEvent>.	839	L<AnyEvent>.
503		840
504	=head1 AUTHOR	841	=head1 AUTHOR

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.22 by root, Tue Aug 4 18:33:30 2009 UTC vs. Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.22 by root, Tue Aug 4 18:33:30 2009 UTC vs.
Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC