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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.26 by root, Tue Aug 4 22:05:43 2009 UTC vs.
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC

…		…
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
		13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node; # -OR-
		17	initialise_node "localhost:4040"; # -OR-
		18	initialise_node "slave/", "localhost:4040"
		19
		20	# ports are message endpoints
		21
		22	# sending messages
13	snd $port, type => data...;	23	snd $port, type => data...;
		24	snd $port, @msg;
		25	snd @msg_with_first_element_being_a_port;
14		26
15	$SELF # receiving/own port id in rcv callbacks	27	# creating/using miniports
		28	my $miniport = port { my @msg = @_; 0 };
16		29
		30	# creating/using full ports
		31	my $port = port;
17	rcv $port, smartmatch => $cb->($port, @msg);	32	rcv $port, smartmatch => $cb->(@msg);
18
19	# examples:
20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
21	rcv $port1, pong => sub { warn "pong received\n" };	34	rcv $port, pong => sub { warn "pong received\n"; 0 };
22	snd $port2, ping => $port1;
23		35
24	# more, smarter, matches (_any_ is exported by this module)	36	# more, smarter, matches (_any_ is exported by this module)
25	rcv $port, [child_died => $pid] => sub { ...	37	rcv $port, [child_died => $pid] => sub { ...
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
27		39
		40	# create a port on another node
		41	my $port = spawn $node, $initfunc, @initdata;
		42
		43	# monitoring
		44	mon $port, $cb->(@msg) # callback is invoked on death
		45	mon $port, $otherport # kill otherport on abnormal death
		46	mon $port, $otherport, @msg # send message on death
		47
		48	=head1 CURRENT STATUS
		49
		50	AnyEvent::MP - stable API, should work
		51	AnyEvent::MP::Intro - outdated
		52	AnyEvent::MP::Kernel - WIP
		53	AnyEvent::MP::Transport - mostly stable
		54
		55	stay tuned.
		56
28	=head1 DESCRIPTION	57	=head1 DESCRIPTION
29		58
30	This module (-family) implements a simple message passing framework.	59	This module (-family) implements a simple message passing framework.
31		60
32	Despite its simplicity, you can securely message other processes running	61	Despite its simplicity, you can securely message other processes running
…		…
35	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	64	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
36	manual page.	65	manual page.
37		66
38	At the moment, this module family is severly broken and underdocumented,	67	At the moment, this module family is severly broken and underdocumented,
39	so do not use. This was uploaded mainly to reserve the CPAN namespace -	68	so do not use. This was uploaded mainly to reserve the CPAN namespace -
40	stay tuned! The basic API should be finished, however.	69	stay tuned!
41		70
42	=head1 CONCEPTS	71	=head1 CONCEPTS
43		72
44	=over 4	73	=over 4
45		74
46	=item port	75	=item port
47		76
48	A port is something you can send messages to with the C<snd> function, and	77	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	78
50	messages they match, messages will not be queued.	79	Some ports allow you to register C<rcv> handlers that can match specific
		80	messages. All C<rcv> handlers will receive messages they match, messages
		81	will not be queued.
51		82
52	=item port id - C<noderef#portname>	83	=item port id - C<noderef#portname>
53		84
54	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	85	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).	86	separator, and a port name (a printable string of unspecified format). An
		87	exception is the the node port, whose ID is identical to its node
		88	reference.
56		89
57	=item node	90	=item node
58		91
59	A node is a single process containing at least one port - the node	92	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,	93	port. You can send messages to node ports to find existing ports or to
61	among other things.	94	create new ports, among other things.
62		95
63	Initially, nodes are either private (single-process only) or hidden	96	Nodes are either private (single-process only), slaves (connected to a
64	(connected to a master node only). Only when they epxlicitly "become	97	master node only) or public nodes (connectable from unrelated nodes).
65	public" can you send them messages from unrelated other nodes.
66		98
67	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
68		100
69	A noderef is a string that either uniquely identifies a given node (for	101	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	102	private and slave nodes), or contains a recipe on how to reach a given
71	node (for public nodes).	103	node (for public nodes).
72		104
		105	This recipe is simply a comma-separated list of C<address:port> pairs (for
		106	TCP/IP, other protocols might look different).
		107
		108	Node references come in two flavours: resolved (containing only numerical
		109	addresses) or unresolved (where hostnames are used instead of addresses).
		110
		111	Before using an unresolved node reference in a message you first have to
		112	resolve it.
		113
73	=back	114	=back
74		115
75	=head1 VARIABLES/FUNCTIONS	116	=head1 VARIABLES/FUNCTIONS
76		117
77	=over 4	118	=over 4
78		119
79	=cut	120	=cut
80		121
81	package AnyEvent::MP;	122	package AnyEvent::MP;
82		123
83	use AnyEvent::MP::Base;	124	use AnyEvent::MP::Kernel;
84		125
85	use common::sense;	126	use common::sense;
86		127
87	use Carp ();	128	use Carp ();
88		129
89	use AE ();	130	use AE ();
90		131
91	use base "Exporter";	132	use base "Exporter";
92		133
93	our $VERSION = '0.1';	134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		135
94	our @EXPORT = qw(	136	our @EXPORT = qw(
95	NODE $NODE *SELF node_of _any_	137	NODE $NODE *SELF node_of _any_
96	become_slave become_public	138	resolve_node initialise_node
97	snd rcv mon kil reg psub	139	snd rcv mon kil reg psub spawn
98	port	140	port
99	);	141	);
100		142
101	our $SELF;	143	our $SELF;
102		144
…		…
111	The C<NODE> function returns, and the C<$NODE> variable contains	153	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	154	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	155	to C<become_public> or C<become_slave>, after which all local port
114	identifiers become invalid.	156	identifiers become invalid.
115		157
116	=item $noderef = node_of $portid	158	=item $noderef = node_of $port
117		159
118	Extracts and returns the noderef from a portid or a noderef.	160	Extracts and returns the noderef from a portid or a noderef.
		161
		162	=item initialise_node $noderef, $seednode, $seednode...
		163
		164	=item initialise_node "slave/", $master, $master...
		165
		166	Before a node can talk to other nodes on the network it has to initialise
		167	itself - the minimum a node needs to know is it's own name, and optionally
		168	it should know the noderefs of some other nodes in the network.
		169
		170	This function initialises a node - it must be called exactly once (or
		171	never) before calling other AnyEvent::MP functions.
		172
		173	All arguments (optionally except for the first) are noderefs, which can be
		174	either resolved or unresolved.
		175
		176	The first argument will be looked up in the configuration database first
		177	(if it is C<undef> then the current nodename will be used instead) to find
		178	the relevant configuration profile (see L<aemp>). If none is found then
		179	the default configuration is used. The configuration supplies additional
		180	seed/master nodes and can override the actual noderef.
		181
		182	There are two types of networked nodes, public nodes and slave nodes:
		183
		184	=over 4
		185
		186	=item public nodes
		187
		188	For public nodes, C<$noderef> (supplied either directly to
		189	C<initialise_node> or indirectly via a profile or the nodename) must be a
		190	noderef (possibly unresolved, in which case it will be resolved).
		191
		192	After resolving, the node will bind itself on all endpoints and try to
		193	connect to all additional C<$seednodes> that are specified. Seednodes are
		194	optional and can be used to quickly bootstrap the node into an existing
		195	network.
		196
		197	=item slave nodes
		198
		199	When the C<$noderef> (either as given or overriden by the config file)
		200	is the special string C<slave/>, then the node will become a slave
		201	node. Slave nodes cannot be contacted from outside and will route most of
		202	their traffic to the master node that they attach to.
		203
		204	At least one additional noderef is required (either by specifying it
		205	directly or because it is part of the configuration profile): The node
		206	will try to connect to all of them and will become a slave attached to the
		207	first node it can successfully connect to.
		208
		209	=back
		210
		211	This function will block until all nodes have been resolved and, for slave
		212	nodes, until it has successfully established a connection to a master
		213	server.
		214
		215	Example: become a public node listening on the guessed noderef, or the one
		216	specified via C<aemp> for the current node. This should be the most common
		217	form of invocation for "daemon"-type nodes.
		218
		219	initialise_node;
		220
		221	Example: become a slave node to any of the the seednodes specified via
		222	C<aemp>. This form is often used for commandline clients.
		223
		224	initialise_node "slave/";
		225
		226	Example: become a slave node to any of the specified master servers. This
		227	form is also often used for commandline clients.
		228
		229	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		230
		231	Example: become a public node, and try to contact some well-known master
		232	servers to become part of the network.
		233
		234	initialise_node undef, "master1", "master2";
		235
		236	Example: become a public node listening on port C<4041>.
		237
		238	initialise_node 4041;
		239
		240	Example: become a public node, only visible on localhost port 4044.
		241
		242	initialise_node "localhost:4044";
		243
		244	=item $cv = resolve_node $noderef
		245
		246	Takes an unresolved node reference that may contain hostnames and
		247	abbreviated IDs, resolves all of them and returns a resolved node
		248	reference.
		249
		250	In addition to C<address:port> pairs allowed in resolved noderefs, the
		251	following forms are supported:
		252
		253	=over 4
		254
		255	=item the empty string
		256
		257	An empty-string component gets resolved as if the default port (4040) was
		258	specified.
		259
		260	=item naked port numbers (e.g. C<1234>)
		261
		262	These are resolved by prepending the local nodename and a colon, to be
		263	further resolved.
		264
		265	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		266
		267	These are resolved by using AnyEvent::DNS to resolve them, optionally
		268	looking up SRV records for the C<aemp=4040> port, if no port was
		269	specified.
		270
		271	=back
119		272
120	=item $SELF	273	=item $SELF
121		274
122	Contains the current port id while executing C<rcv> callbacks or C<psub>	275	Contains the current port id while executing C<rcv> callbacks or C<psub>
123	blocks.	276	blocks.
…		…
126		279
127	Due to some quirks in how perl exports variables, it is impossible to	280	Due to some quirks in how perl exports variables, it is impossible to
128	just export C<$SELF>, all the symbols called C<SELF> are exported by this	281	just export C<$SELF>, all the symbols called C<SELF> are exported by this
129	module, but only C<$SELF> is currently used.	282	module, but only C<$SELF> is currently used.
130		283
131	=item snd $portid, type => @data	284	=item snd $port, type => @data
132		285
133	=item snd $portid, @msg	286	=item snd $port, @msg
134		287
135	Send the given message to the given port ID, which can identify either	288	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	289	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 :).	290	stringifies a sa port ID (such as a port object :).
138		291
…		…
148	JSON is used, then only strings, numbers and arrays and hashes consisting	301	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	302	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	303	that Storable can serialise and deserialise is allowed, and for the local
151	node, anything can be passed.	304	node, anything can be passed.
152		305
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	306	=item $local_port = port
261		307
262	Create a new local port object that supports message matching.	308	Create a new local port object that can be used either as a pattern
		309	matching port ("full port") or a single-callback port ("miniport"),
		310	depending on how C<rcv> callbacks are bound to the object.
263		311
264	=item $portid = port { my @msg = @_; $finished }	312	=item $port = port { my @msg = @_; $finished }
265		313
266	Creates a "mini port", that is, a very lightweight port without any	314	Creates a "miniport", that is, a very lightweight port without any pattern
267	pattern matching behind it, and returns its ID.	315	matching behind it, and returns its ID. Semantically the same as creating
		316	a port and calling C<rcv $port, $callback> on it.
268		317
269	The block will be called for every message received on the port. When the	318	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	319	callback returns a true value its job is considered "done" and the port
271	will be destroyed. Otherwise it will stay alive.	320	will be destroyed. Otherwise it will stay alive.
272		321
273	The message will be passed as-is, no extra argument (i.e. no port id) will	322	The message will be passed as-is, no extra argument (i.e. no port id) will
274	be passed to the callback.	323	be passed to the callback.
275		324
276	If you need the local port id in the callback, this works nicely:	325	If you need the local port id in the callback, this works nicely:
277		326
278	my $port; $port = miniport {	327	my $port; $port = port {
279	snd $otherport, reply => $port;	328	snd $otherport, reply => $port;
280	};	329	};
281		330
282	=cut	331	=cut
		332
		333	sub rcv($@);
283		334
284	sub port(;&) {	335	sub port(;&) {
285	my $id = "$UNIQ." . $ID++;	336	my $id = "$UNIQ." . $ID++;
286	my $port = "$NODE#$id";	337	my $port = "$NODE#$id";
287		338
288	if (@_) {	339	if (@_) {
		340	rcv $port, shift;
		341	} else {
		342	$PORT{$id} = sub { }; # nop
		343	}
		344
		345	$port
		346	}
		347
		348	=item reg $port, $name
		349
		350	=item reg $name
		351
		352	Registers the given port (or C<$SELF><<< if missing) under the name
		353	C<$name>. If the name already exists it is replaced.
		354
		355	A port can only be registered under one well known name.
		356
		357	A port automatically becomes unregistered when it is killed.
		358
		359	=cut
		360
		361	sub reg(@) {
		362	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		363
		364	$REG{$_[0]} = $port;
		365	}
		366
		367	=item rcv $port, $callback->(@msg)
		368
		369	Replaces the callback on the specified miniport (after converting it to
		370	one if required).
		371
		372	=item rcv $port, tagstring => $callback->(@msg), ...
		373
		374	=item rcv $port, $smartmatch => $callback->(@msg), ...
		375
		376	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		377
		378	Register callbacks to be called on matching messages on the given full
		379	port (after converting it to one if required) and return the port.
		380
		381	The callback has to return a true value when its work is done, after
		382	which is will be removed, or a false value in which case it will stay
		383	registered.
		384
		385	The global C<$SELF> (exported by this module) contains C<$port> while
		386	executing the callback.
		387
		388	Runtime errors during callback execution will result in the port being
		389	C<kil>ed.
		390
		391	If the match is an array reference, then it will be matched against the
		392	first elements of the message, otherwise only the first element is being
		393	matched.
		394
		395	Any element in the match that is specified as C<_any_> (a function
		396	exported by this module) matches any single element of the message.
		397
		398	While not required, it is highly recommended that the first matching
		399	element is a string identifying the message. The one-string-only match is
		400	also the most efficient match (by far).
		401
		402	Example: create a port and bind receivers on it in one go.
		403
		404	my $port = rcv port,
		405	msg1 => sub { ...; 0 },
		406	msg2 => sub { ...; 0 },
		407	;
		408
		409	Example: create a port, bind receivers and send it in a message elsewhere
		410	in one go:
		411
		412	snd $otherport, reply =>
		413	rcv port,
		414	msg1 => sub { ...; 0 },
		415	...
		416	;
		417
		418	=cut
		419
		420	sub rcv($@) {
		421	my $port = shift;
		422	my ($noderef, $portid) = split /#/, $port, 2;
		423
		424	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		425	or Carp::croak "$port: rcv can only be called on local ports, caught";
		426
		427	if (@_ == 1) {
289	my $cb = shift;	428	my $cb = shift;
		429	delete $PORT_DATA{$portid};
290	$PORT{$id} = sub {	430	$PORT{$portid} = sub {
291	local $SELF = $port;	431	local $SELF = $port;
292	eval {	432	eval {
293	&$cb	433	&$cb
294	and kil $id;	434	and kil $port;
295	};	435	};
296	_self_die if $@;	436	_self_die if $@;
297	};	437	};
298	} else {	438	} else {
		439	my $self = $PORT_DATA{$portid} \|\|= do {
299	my $self = bless {	440	my $self = bless {
300	id => "$NODE#$id",	441	id => $port,
301	}, "AnyEvent::MP::Port";	442	}, "AnyEvent::MP::Port";
302		443
303	$PORT_DATA{$id} = $self;
304	$PORT{$id} = sub {	444	$PORT{$portid} = sub {
305	local $SELF = $port;	445	local $SELF = $port;
306		446
307	eval {	447	eval {
308	for (@{ $self->{rc0}{$_[0]} }) {	448	for (@{ $self->{rc0}{$_[0]} }) {
309	$_ && &{$_->[0]}	449	$_ && &{$_->[0]}
310	&& undef $_;	450	&& undef $_;
311	}	451	}
312		452
313	for (@{ $self->{rcv}{$_[0]} }) {	453	for (@{ $self->{rcv}{$_[0]} }) {
314	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	454	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
315	&& &{$_->[0]}	455	&& &{$_->[0]}
316	&& undef $_;	456	&& undef $_;
317	}	457	}
318		458
319	for (@{ $self->{any} }) {	459	for (@{ $self->{any} }) {
320	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	460	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
321	&& &{$_->[0]}	461	&& &{$_->[0]}
322	&& undef $_;	462	&& undef $_;
		463	}
323	}	464	};
		465	_self_die if $@;
324	};	466	};
325	_self_die if $@;	467
		468	$self
326	};	469	};
327	}
328		470
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	471	"AnyEvent::MP::Port" eq ref $self
390	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";	472	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
391		473
392	while (@_) {	474	while (@_) {
393	my ($match, $cb) = splice @_, 0, 2;	475	my ($match, $cb) = splice @_, 0, 2;
394		476
395	if (!ref $match) {	477	if (!ref $match) {
396	push @{ $self->{rc0}{$match} }, [$cb];	478	push @{ $self->{rc0}{$match} }, [$cb];
397	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	479	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
398	my ($type, @match) = @$match;	480	my ($type, @match) = @$match;
399	@match	481	@match
400	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	482	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
401	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	483	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
402	} else {	484	} else {
403	push @{ $self->{any} }, [$cb, $match];	485	push @{ $self->{any} }, [$cb, $match];
		486	}
404	}	487	}
405	}	488	}
		489
		490	$port
406	}	491	}
407		492
408	=item $closure = psub { BLOCK }	493	=item $closure = psub { BLOCK }
409		494
410	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	495	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
…		…
441	$res	526	$res
442	}	527	}
443	}	528	}
444	}	529	}
445		530
446	=back	531	=item $guard = mon $port, $cb->(@reason)
447		532
448	=head1 FUNCTIONS FOR NODES	533	=item $guard = mon $port, $rcvport
449		534
450	=over 4	535	=item $guard = mon $port
451		536
452	=item become_public endpoint...	537	=item $guard = mon $port, $rcvport, @msg
453		538
454	Tells the node to become a public node, i.e. reachable from other nodes.	539	Monitor the given port and do something when the port is killed or
		540	messages to it were lost, and optionally return a guard that can be used
		541	to stop monitoring again.
455		542
456	If no arguments are given, or the first argument is C<undef>, then	543	C<mon> effectively guarantees that, in the absence of hardware failures,
457	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the	544	that after starting the monitor, either all messages sent to the port
458	local nodename resolves to.	545	will arrive, or the monitoring action will be invoked after possible
		546	message loss has been detected. No messages will be lost "in between"
		547	(after the first lost message no further messages will be received by the
		548	port). After the monitoring action was invoked, further messages might get
		549	delivered again.
459		550
460	Otherwise the first argument must be an array-reference with transport	551	In the first form (callback), the callback is simply called with any
461	endpoints ("ip:port", "hostname:port") or port numbers (in which case the	552	number of C<@reason> elements (no @reason means that the port was deleted
462	local nodename is used as hostname). The endpoints are all resolved and	553	"normally"). Note also that I<< the callback B<must> never die >>, so use
463	will become the node reference.	554	C<eval> if unsure.
464		555
		556	In the second form (another port given), the other port (C<$rcvport>)
		557	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
		558	"normal" kils nothing happens, while under all other conditions, the other
		559	port is killed with the same reason.
		560
		561	The third form (kill self) is the same as the second form, except that
		562	C<$rvport> defaults to C<$SELF>.
		563
		564	In the last form (message), a message of the form C<@msg, @reason> will be
		565	C<snd>.
		566
		567	As a rule of thumb, monitoring requests should always monitor a port from
		568	a local port (or callback). The reason is that kill messages might get
		569	lost, just like any other message. Another less obvious reason is that
		570	even monitoring requests can get lost (for exmaple, when the connection
		571	to the other node goes down permanently). When monitoring a port locally
		572	these problems do not exist.
		573
		574	Example: call a given callback when C<$port> is killed.
		575
		576	mon $port, sub { warn "port died because of <@_>\n" };
		577
		578	Example: kill ourselves when C<$port> is killed abnormally.
		579
		580	mon $port;
		581
		582	Example: send us a restart message when another C<$port> is killed.
		583
		584	mon $port, $self => "restart";
		585
465	=cut	586	=cut
		587
		588	sub mon {
		589	my ($noderef, $port) = split /#/, shift, 2;
		590
		591	my $node = $NODE{$noderef} \|\| add_node $noderef;
		592
		593	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
		594
		595	unless (ref $cb) {
		596	if (@_) {
		597	# send a kill info message
		598	my (@msg) = ($cb, @_);
		599	$cb = sub { snd @msg, @_ };
		600	} else {
		601	# simply kill other port
		602	my $port = $cb;
		603	$cb = sub { kil $port, @_ if @_ };
		604	}
		605	}
		606
		607	$node->monitor ($port, $cb);
		608
		609	defined wantarray
		610	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		611	}
		612
		613	=item $guard = mon_guard $port, $ref, $ref...
		614
		615	Monitors the given C<$port> and keeps the passed references. When the port
		616	is killed, the references will be freed.
		617
		618	Optionally returns a guard that will stop the monitoring.
		619
		620	This function is useful when you create e.g. timers or other watchers and
		621	want to free them when the port gets killed:
		622
		623	$port->rcv (start => sub {
		624	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		625	undef $timer if 0.9 < rand;
		626	});
		627	});
		628
		629	=cut
		630
		631	sub mon_guard {
		632	my ($port, @refs) = @_;
		633
		634	#TODO: mon-less form?
		635
		636	mon $port, sub { 0 && @refs }
		637	}
		638
		639	=item kil $port[, @reason]
		640
		641	Kill the specified port with the given C<@reason>.
		642
		643	If no C<@reason> is specified, then the port is killed "normally" (linked
		644	ports will not be kileld, or even notified).
		645
		646	Otherwise, linked ports get killed with the same reason (second form of
		647	C<mon>, see below).
		648
		649	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		650	will be reported as reason C<< die => $@ >>.
		651
		652	Transport/communication errors are reported as C<< transport_error =>
		653	$message >>.
		654
		655	=cut
		656
		657	=item $port = spawn $node, $initfunc[, @initdata]
		658
		659	Creates a port on the node C<$node> (which can also be a port ID, in which
		660	case it's the node where that port resides).
		661
		662	The port ID of the newly created port is return immediately, and it is
		663	permissible to immediately start sending messages or monitor the port.
		664
		665	After the port has been created, the init function is
		666	called. This function must be a fully-qualified function name
		667	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		668	program, use C<::name>.
		669
		670	If the function doesn't exist, then the node tries to C<require>
		671	the package, then the package above the package and so on (e.g.
		672	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		673	exists or it runs out of package names.
		674
		675	The init function is then called with the newly-created port as context
		676	object (C<$SELF>) and the C<@initdata> values as arguments.
		677
		678	A common idiom is to pass your own port, monitor the spawned port, and
		679	in the init function, monitor the original port. This two-way monitoring
		680	ensures that both ports get cleaned up when there is a problem.
		681
		682	Example: spawn a chat server port on C<$othernode>.
		683
		684	# this node, executed from within a port context:
		685	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		686	mon $server;
		687
		688	# init function on C<$othernode>
		689	sub connect {
		690	my ($srcport) = @_;
		691
		692	mon $srcport;
		693
		694	rcv $SELF, sub {
		695	...
		696	};
		697	}
		698
		699	=cut
		700
		701	sub _spawn {
		702	my $port = shift;
		703	my $init = shift;
		704
		705	local $SELF = "$NODE#$port";
		706	eval {
		707	&{ load_func $init }
		708	};
		709	_self_die if $@;
		710	}
		711
		712	sub spawn(@) {
		713	my ($noderef, undef) = split /#/, shift, 2;
		714
		715	my $id = "$RUNIQ." . $ID++;
		716
		717	$_[0] =~ /::/
		718	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		719
		720	($NODE{$noderef} \|\| add_node $noderef)
		721	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		722
		723	"$noderef#$id"
		724	}
466		725
467	=back	726	=back
468		727
469	=head1 NODE MESSAGES	728	=head1 NODE MESSAGES
470		729
471	Nodes understand the following messages sent to them. Many of them take	730	Nodes understand the following messages sent to them. Many of them take
472	arguments called C<@reply>, which will simply be used to compose a reply	731	arguments called C<@reply>, which will simply be used to compose a reply
473	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	732	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
474	the remaining arguments are simply the message data.	733	the remaining arguments are simply the message data.
475		734
		735	While other messages exist, they are not public and subject to change.
		736
476	=over 4	737	=over 4
477		738
478	=cut	739	=cut
479		740
480	=item lookup => $name, @reply	741	=item lookup => $name, @reply
…		…
510		771
511	=back	772	=back
512		773
513	=head1 AnyEvent::MP vs. Distributed Erlang	774	=head1 AnyEvent::MP vs. Distributed Erlang
514		775
515	AnyEvent::MP got lots of its ideas from distributed erlang. Despite the	776	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
516	similarities (erlang node == aemp node, erlang process == aemp port and so	777	== aemp node, Erlang process == aemp port), so many of the documents and
		778	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		779	sample:
		780
		781	http://www.Erlang.se/doc/programming_rules.shtml
		782	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		783	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		784	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		785
517	on), there are also some important differences:	786	Despite the similarities, there are also some important differences:
518		787
519	=over 4	788	=over 4
520		789
521	=item * Node references contain the recipe on how to contact them.	790	=item * Node references contain the recipe on how to contact them.
522		791
523	Erlang relies on special naming and DNS to work everywhere in the	792	Erlang relies on special naming and DNS to work everywhere in the
524	same way. AEMP relies on each node knowing it's own address(es), with	793	same way. AEMP relies on each node knowing it's own address(es), with
525	convenience functionality.	794	convenience functionality.
526		795
		796	This means that AEMP requires a less tightly controlled environment at the
		797	cost of longer node references and a slightly higher management overhead.
		798
527	=item * Erlang uses processes and a mailbox, AEMP does not queue.	799	=item * Erlang uses processes and a mailbox, AEMP does not queue.
528		800
529	Erlang uses processes that selctively receive messages, and therefore	801	Erlang uses processes that selctively receive messages, and therefore
530	needs a queue. AEMP is event based, queuing messages would serve no useful	802	needs a queue. AEMP is event based, queuing messages would serve no useful
531	purpose.	803	purpose.
532		804
533	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).	805	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
534		806
535	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	807	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
536		808
537	Sending messages in erlang is synchronous and blocks the process. AEMP	809	Sending messages in Erlang is synchronous and blocks the process. AEMP
538	sends are immediate, connection establishment is handled in the	810	sends are immediate, connection establishment is handled in the
539	background.	811	background.
540		812
541	=item * Erlang can silently lose messages, AEMP cannot.	813	=item * Erlang can silently lose messages, AEMP cannot.
542		814
…		…
545	and c, and the other side only receives messages a and c).	817	and c, and the other side only receives messages a and c).
546		818
547	AEMP guarantees correct ordering, and the guarantee that there are no	819	AEMP guarantees correct ordering, and the guarantee that there are no
548	holes in the message sequence.	820	holes in the message sequence.
549		821
550	=item * In erlang, processes can be declared dead and later be found to be	822	=item * In Erlang, processes can be declared dead and later be found to be
551	alive.	823	alive.
552		824
553	In erlang it can happen that a monitored process is declared dead and	825	In Erlang it can happen that a monitored process is declared dead and
554	linked processes get killed, but later it turns out that the process is	826	linked processes get killed, but later it turns out that the process is
555	still alive - and can receive messages.	827	still alive - and can receive messages.
556		828
557	In AEMP, when port monitoring detects a port as dead, then that port will	829	In AEMP, when port monitoring detects a port as dead, then that port will
558	eventually be killed - it cannot happen that a node detects a port as dead	830	eventually be killed - it cannot happen that a node detects a port as dead
559	and then later sends messages to it, finding it is still alive.	831	and then later sends messages to it, finding it is still alive.
560		832
561	=item * Erlang can send messages to the wrong port, AEMP does not.	833	=item * Erlang can send messages to the wrong port, AEMP does not.
562		834
563	In erlang it is quite possible that a node that restarts reuses a process	835	In Erlang it is quite possible that a node that restarts reuses a process
564	ID known to other nodes for a completely different process, causing	836	ID known to other nodes for a completely different process, causing
565	messages destined for that process to end up in an unrelated process.	837	messages destined for that process to end up in an unrelated process.
566		838
567	AEMP never reuses port IDs, so old messages or old port IDs floating	839	AEMP never reuses port IDs, so old messages or old port IDs floating
568	around in the network will not be sent to an unrelated port.	840	around in the network will not be sent to an unrelated port.
…		…
571	authentication and can use TLS.	843	authentication and can use TLS.
572		844
573	AEMP can use a proven protocol - SSL/TLS - to protect connections and	845	AEMP can use a proven protocol - SSL/TLS - to protect connections and
574	securely authenticate nodes.	846	securely authenticate nodes.
575		847
		848	=item * The AEMP protocol is optimised for both text-based and binary
		849	communications.
		850
		851	The AEMP protocol, unlike the Erlang protocol, supports both
		852	language-independent text-only protocols (good for debugging) and binary,
		853	language-specific serialisers (e.g. Storable).
		854
		855	It has also been carefully designed to be implementable in other languages
		856	with a minimum of work while gracefully degrading fucntionality to make the
		857	protocol simple.
		858
		859	=item * AEMP has more flexible monitoring options than Erlang.
		860
		861	In Erlang, you can chose to receive I<all> exit signals as messages
		862	or I<none>, there is no in-between, so monitoring single processes is
		863	difficult to implement. Monitoring in AEMP is more flexible than in
		864	Erlang, as one can choose between automatic kill, exit message or callback
		865	on a per-process basis.
		866
		867	=item * Erlang tries to hide remote/local connections, AEMP does not.
		868
		869	Monitoring in Erlang is not an indicator of process death/crashes,
		870	as linking is (except linking is unreliable in Erlang).
		871
		872	In AEMP, you don't "look up" registered port names or send to named ports
		873	that might or might not be persistent. Instead, you normally spawn a port
		874	on the remote node. The init function monitors the you, and you monitor
		875	the remote port. Since both monitors are local to the node, they are much
		876	more reliable.
		877
		878	This also saves round-trips and avoids sending messages to the wrong port
		879	(hard to do in Erlang).
		880
		881	=back
		882
		883	=head1 RATIONALE
		884
		885	=over 4
		886
		887	=item Why strings for ports and noderefs, why not objects?
		888
		889	We considered "objects", but found that the actual number of methods
		890	thatc an be called are very low. Since port IDs and noderefs travel over
		891	the network frequently, the serialising/deserialising would add lots of
		892	overhead, as well as having to keep a proxy object.
		893
		894	Strings can easily be printed, easily serialised etc. and need no special
		895	procedures to be "valid".
		896
		897	And a a miniport consists of a single closure stored in a global hash - it
		898	can't become much cheaper.
		899
		900	=item Why favour JSON, why not real serialising format such as Storable?
		901
		902	In fact, any AnyEvent::MP node will happily accept Storable as framing
		903	format, but currently there is no way to make a node use Storable by
		904	default.
		905
		906	The default framing protocol is JSON because a) JSON::XS is many times
		907	faster for small messages and b) most importantly, after years of
		908	experience we found that object serialisation is causing more problems
		909	than it gains: Just like function calls, objects simply do not travel
		910	easily over the network, mostly because they will always be a copy, so you
		911	always have to re-think your design.
		912
		913	Keeping your messages simple, concentrating on data structures rather than
		914	objects, will keep your messages clean, tidy and efficient.
		915
576	=back	916	=back
577		917
578	=head1 SEE ALSO	918	=head1 SEE ALSO
579		919
580	L<AnyEvent>.	920	L<AnyEvent>.

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Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC