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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs.
Revision 1.74 by root, Mon Aug 31 11:11:27 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	configure;
		17
		18	# ports are message endpoints
		19
		20	# sending messages
13	snd $port, type => data...;	21	snd $port, type => data...;
		22	snd $port, @msg;
		23	snd @msg_with_first_element_being_a_port;
14		24
15	$SELF # receiving/own port id in rcv callbacks	25	# creating/using ports, the simple way
		26	my $simple_port = port { my @msg = @_ };
16		27
17	rcv $port, smartmatch => $cb->($port, @msg);	28	# creating/using ports, tagged message matching
18		29	my $port = port;
19	# examples:
20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong" };
21	rcv $port1, pong => sub { warn "pong received\n" };	31	rcv $port, pong => sub { warn "pong received\n" };
22	snd $port2, ping => $port1;
23		32
24	# more, smarter, matches (_any_ is exported by this module)	33	# create a port on another node
25	rcv $port, [child_died => $pid] => sub { ...	34	my $port = spawn $node, $initfunc, @initdata;
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
27
28	# linking two ports, so they both crash together
29	lnk $port1, $port2;
30		35
31	# monitoring	36	# monitoring
32	mon $port, $cb->(@msg) # callback is invoked on death	37	mon $port, $cb->(@msg) # callback is invoked on death
33	mon $port, $otherport # kill otherport on abnormal death	38	mon $port, $otherport # kill otherport on abnormal death
34	mon $port, $otherport, @msg # send message on death	39	mon $port, $otherport, @msg # send message on death
35		40
		41	=head1 CURRENT STATUS
		42
		43	bin/aemp - stable.
		44	AnyEvent::MP - stable API, should work.
		45	AnyEvent::MP::Intro - uptodate, but incomplete.
		46	AnyEvent::MP::Kernel - mostly stable.
		47	AnyEvent::MP::Global - stable API, protocol not yet final.
		48
		49	stay tuned.
		50
36	=head1 DESCRIPTION	51	=head1 DESCRIPTION
37		52
38	This module (-family) implements a simple message passing framework.	53	This module (-family) implements a simple message passing framework.
39		54
40	Despite its simplicity, you can securely message other processes running	55	Despite its simplicity, you can securely message other processes running
41	on the same or other hosts.	56	on the same or other hosts, and you can supervise entities remotely.
42		57
43	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	58	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
44	manual page.	59	manual page and the examples under F<eg/>.
45		60
46	At the moment, this module family is severly broken and underdocumented,	61	At the moment, this module family is a bit underdocumented.
47	so do not use. This was uploaded mainly to reserve the CPAN namespace -
48	stay tuned! The basic API should be finished, however.
49		62
50	=head1 CONCEPTS	63	=head1 CONCEPTS
51		64
52	=over 4	65	=over 4
53		66
54	=item port	67	=item port
55		68
56	A port is something you can send messages to (with the C<snd> function).	69	A port is something you can send messages to (with the C<snd> function).
57		70
58	Some ports allow you to register C<rcv> handlers that can match specific	71	Ports allow you to register C<rcv> handlers that can match all or just
59	messages. All C<rcv> handlers will receive messages they match, messages	72	some messages. Messages send to ports will not be queued, regardless of
60	will not be queued.	73	anything was listening for them or not.
61		74
62	=item port id - C<noderef#portname>	75	=item port ID - C<nodeid#portname>
63		76
64	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	77	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
65	separator, and a port name (a printable string of unspecified format). An	78	separator, and a port name (a printable string of unspecified format).
66	exception is the the node port, whose ID is identical to its node
67	reference.
68		79
69	=item node	80	=item node
70		81
71	A node is a single process containing at least one port - the node	82	A node is a single process containing at least one port - the node port,
72	port. You can send messages to node ports to find existing ports or to	83	which enables nodes to manage each other remotely, and to create new
73	create new ports, among other things.	84	ports.
74		85
75	Nodes are either private (single-process only), slaves (connected to a	86	Nodes are either public (have one or more listening ports) or private
76	master node only) or public nodes (connectable from unrelated nodes).	87	(no listening ports). Private nodes cannot talk to other private nodes
		88	currently.
77		89
78	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	90	=item node ID - C<[a-za-Z0-9_\-.:]+>
79		91
80	A node reference is a string that either simply identifies the node (for	92	A node ID is a string that uniquely identifies the node within a
81	private and slave nodes), or contains a recipe on how to reach a given	93	network. Depending on the configuration used, node IDs can look like a
82	node (for public nodes).	94	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		95	doesn't interpret node IDs in any way.
83		96
84	This recipe is simply a comma-separated list of C<address:port> pairs (for	97	=item binds - C<ip:port>
85	TCP/IP, other protocols might look different).
86		98
87	Node references come in two flavours: resolved (containing only numerical	99	Nodes can only talk to each other by creating some kind of connection to
88	addresses) or unresolved (where hostnames are used instead of addresses).	100	each other. To do this, nodes should listen on one or more local transport
		101	endpoints - binds. Currently, only standard C<ip:port> specifications can
		102	be used, which specify TCP ports to listen on.
89		103
90	Before using an unresolved node reference in a message you first have to	104	=item seeds - C<host:port>
91	resolve it.	105
		106	When a node starts, it knows nothing about the network. To teach the node
		107	about the network it first has to contact some other node within the
		108	network. This node is called a seed.
		109
		110	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		111	are expected to be long-running, and at least one of those should always
		112	be available. When nodes run out of connections (e.g. due to a network
		113	error), they try to re-establish connections to some seednodes again to
		114	join the network.
		115
		116	Apart from being sued for seeding, seednodes are not special in any way -
		117	every public node can be a seednode.
92		118
93	=back	119	=back
94		120
95	=head1 VARIABLES/FUNCTIONS	121	=head1 VARIABLES/FUNCTIONS
96		122
…		…
98		124
99	=cut	125	=cut
100		126
101	package AnyEvent::MP;	127	package AnyEvent::MP;
102		128
103	use AnyEvent::MP::Base;	129	use AnyEvent::MP::Kernel;
104		130
105	use common::sense;	131	use common::sense;
106		132
107	use Carp ();	133	use Carp ();
108		134
109	use AE ();	135	use AE ();
110		136
111	use base "Exporter";	137	use base "Exporter";
112		138
113	our $VERSION = '0.1';	139	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		140
114	our @EXPORT = qw(	141	our @EXPORT = qw(
115	NODE $NODE *SELF node_of _any_	142	NODE $NODE *SELF node_of after
116	resolve_node initialise_node	143	configure
117	snd rcv mon kil reg psub	144	snd rcv mon mon_guard kil reg psub spawn
118	port	145	port
119	);	146	);
120		147
121	our $SELF;	148	our $SELF;
122		149
…		…
126	kil $SELF, die => $msg;	153	kil $SELF, die => $msg;
127	}	154	}
128		155
129	=item $thisnode = NODE / $NODE	156	=item $thisnode = NODE / $NODE
130		157
131	The C<NODE> function returns, and the C<$NODE> variable contains	158	The C<NODE> function returns, and the C<$NODE> variable contains, the node
132	the noderef of the local node. The value is initialised by a call	159	ID of the node running in the current process. This value is initialised by
133	to C<become_public> or C<become_slave>, after which all local port	160	a call to C<configure>.
134	identifiers become invalid.
135		161
136	=item $noderef = node_of $port	162	=item $nodeid = node_of $port
137		163
138	Extracts and returns the noderef from a portid or a noderef.	164	Extracts and returns the node ID from a port ID or a node ID.
139		165
140	=item initialise_node $noderef, $seednode, $seednode...	166	=item configure key => value...
141		167
142	=item initialise_node "slave/", $master, $master...
143
144	Before a node can talk to other nodes on the network it has to initialise	168	Before a node can talk to other nodes on the network (i.e. enter
145	itself - the minimum a node needs to know is it's own name, and optionally	169	"distributed mode") it has to configure itself - the minimum a node needs
146	it should know the noderefs of some other nodes in the network.	170	to know is its own name, and optionally it should know the addresses of
		171	some other nodes in the network to discover other nodes.
147		172
148	This function initialises a node - it must be called exactly once (or	173	This function configures a node - it must be called exactly once (or
149	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
150		175
151	All arguments are noderefs, which can be either resolved or unresolved.
152
153	There are two types of networked nodes, public nodes and slave nodes:
154
155	=over 4	176	=over 4
156		177
157	=item public nodes	178	=item step 1, gathering configuration from profiles
158		179
159	For public nodes, C<$noderef> must either be a (possibly unresolved)	180	The function first looks up a profile in the aemp configuration (see the
160	noderef, in which case it will be resolved, or C<undef> (or missing), in	181	L<aemp> commandline utility). The profile name can be specified via the
161	which case the noderef will be guessed.	182	named C<profile> parameter. If it is missing, then the nodename (F<uname
		183	-n>) will be used as profile name.
162		184
163	Afterwards, the node will bind itself on all endpoints and try to connect	185	The profile data is then gathered as follows:
164	to all additional C<$seednodes> that are specified. Seednodes are optional
165	and can be used to quickly bootstrap the node into an existing network.
166		186
167	=item slave nodes	187	First, all remaining key => value pairs (all of which are conviniently
		188	undocumented at the moment) will be interpreted as configuration
		189	data. Then they will be overwritten by any values specified in the global
		190	default configuration (see the F<aemp> utility), then the chain of
		191	profiles chosen by the profile name (and any C<parent> attributes).
168		192
169	When the C<$noderef> is the special string C<slave/>, then the node will	193	That means that the values specified in the profile have highest priority
170	become a slave node. Slave nodes cannot be contacted from outside and will	194	and the values specified directly via C<configure> have lowest priority,
171	route most of their traffic to the master node that they attach to.	195	and can only be used to specify defaults.
172		196
173	At least one additional noderef is required: The node will try to connect	197	If the profile specifies a node ID, then this will become the node ID of
174	to all of them and will become a slave attached to the first node it can	198	this process. If not, then the profile name will be used as node ID. The
175	successfully connect to.	199	special node ID of C<anon/> will be replaced by a random node ID.
		200
		201	=item step 2, bind listener sockets
		202
		203	The next step is to look up the binds in the profile, followed by binding
		204	aemp protocol listeners on all binds specified (it is possible and valid
		205	to have no binds, meaning that the node cannot be contacted form the
		206	outside. This means the node cannot talk to other nodes that also have no
		207	binds, but it can still talk to all "normal" nodes).
		208
		209	If the profile does not specify a binds list, then a default of C<*> is
		210	used, meaning the node will bind on a dynamically-assigned port on every
		211	local IP address it finds.
		212
		213	=item step 3, connect to seed nodes
		214
		215	As the last step, the seeds list from the profile is passed to the
		216	L<AnyEvent::MP::Global> module, which will then use it to keep
		217	connectivity with at least one node at any point in time.
176		218
177	=back	219	=back
178		220
179	This function will block until all nodes have been resolved and, for slave	221	Example: become a distributed node using the locla node name as profile.
180	nodes, until it has successfully established a connection to a master	222	This should be the most common form of invocation for "daemon"-type nodes.
181	server.
182		223
183	Example: become a public node listening on the default node.	224	configure
184		225
185	initialise_node;	226	Example: become an anonymous node. This form is often used for commandline
		227	clients.
186		228
187	Example: become a public node, and try to contact some well-known master	229	configure nodeid => "anon/";
188	servers to become part of the network.
189		230
190	initialise_node undef, "master1", "master2";	231	Example: configure a node using a profile called seed, which si suitable
		232	for a seed node as it binds on all local addresses on a fixed port (4040,
		233	customary for aemp).
191		234
192	Example: become a public node listening on port C<4041>.	235	# use the aemp commandline utility
		236	# aemp profile seed nodeid anon/ binds '*:4040'
193		237
194	initialise_node 4041;	238	# then use it
		239	configure profile => "seed";
195		240
196	Example: become a public node, only visible on localhost port 4044.	241	# or simply use aemp from the shell again:
		242	# aemp run profile seed
197		243
198	initialise_node "locahost:4044";	244	# or provide a nicer-to-remember nodeid
199		245	# aemp run profile seed nodeid "$(hostname)"
200	Example: become a slave node to any of the specified master servers.
201
202	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
203
204	=item $cv = resolve_node $noderef
205
206	Takes an unresolved node reference that may contain hostnames and
207	abbreviated IDs, resolves all of them and returns a resolved node
208	reference.
209
210	In addition to C<address:port> pairs allowed in resolved noderefs, the
211	following forms are supported:
212
213	=over 4
214
215	=item the empty string
216
217	An empty-string component gets resolved as if the default port (4040) was
218	specified.
219
220	=item naked port numbers (e.g. C<1234>)
221
222	These are resolved by prepending the local nodename and a colon, to be
223	further resolved.
224
225	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
226
227	These are resolved by using AnyEvent::DNS to resolve them, optionally
228	looking up SRV records for the C<aemp=4040> port, if no port was
229	specified.
230
231	=back
232		246
233	=item $SELF	247	=item $SELF
234		248
235	Contains the current port id while executing C<rcv> callbacks or C<psub>	249	Contains the current port id while executing C<rcv> callbacks or C<psub>
236	blocks.	250	blocks.
237		251
238	=item SELF, %SELF, @SELF...	252	=item *SELF, SELF, %SELF, @SELF...
239		253
240	Due to some quirks in how perl exports variables, it is impossible to	254	Due to some quirks in how perl exports variables, it is impossible to
241	just export C<$SELF>, all the symbols called C<SELF> are exported by this	255	just export C<$SELF>, all the symbols named C<SELF> are exported by this
242	module, but only C<$SELF> is currently used.	256	module, but only C<$SELF> is currently used.
243		257
244	=item snd $port, type => @data	258	=item snd $port, type => @data
245		259
246	=item snd $port, @msg	260	=item snd $port, @msg
247		261
248	Send the given message to the given port ID, which can identify either	262	Send the given message to the given port, which can identify either a
249	a local or a remote port, and can be either a string or soemthignt hat	263	local or a remote port, and must be a port ID.
250	stringifies a sa port ID (such as a port object :).
251		264
252	While the message can be about anything, it is highly recommended to use a	265	While the message can be almost anything, it is highly recommended to
253	string as first element (a portid, or some word that indicates a request	266	use a string as first element (a port ID, or some word that indicates a
254	type etc.).	267	request type etc.) and to consist if only simple perl values (scalars,
		268	arrays, hashes) - if you think you need to pass an object, think again.
255		269
256	The message data effectively becomes read-only after a call to this	270	The message data logically becomes read-only after a call to this
257	function: modifying any argument is not allowed and can cause many	271	function: modifying any argument (or values referenced by them) is
258	problems.	272	forbidden, as there can be considerable time between the call to C<snd>
		273	and the time the message is actually being serialised - in fact, it might
		274	never be copied as within the same process it is simply handed to the
		275	receiving port.
259		276
260	The type of data you can transfer depends on the transport protocol: when	277	The type of data you can transfer depends on the transport protocol: when
261	JSON is used, then only strings, numbers and arrays and hashes consisting	278	JSON is used, then only strings, numbers and arrays and hashes consisting
262	of those are allowed (no objects). When Storable is used, then anything	279	of those are allowed (no objects). When Storable is used, then anything
263	that Storable can serialise and deserialise is allowed, and for the local	280	that Storable can serialise and deserialise is allowed, and for the local
264	node, anything can be passed.	281	node, anything can be passed. Best rely only on the common denominator of
		282	these.
265		283
266	=item $local_port = port	284	=item $local_port = port
267		285
268	Create a new local port object that can be used either as a pattern	286	Create a new local port object and returns its port ID. Initially it has
269	matching port ("full port") or a single-callback port ("miniport"),	287	no callbacks set and will throw an error when it receives messages.
270	depending on how C<rcv> callbacks are bound to the object.
271		288
272	=item $port = port { my @msg = @_; $finished }	289	=item $local_port = port { my @msg = @_ }
273		290
274	Creates a "miniport", that is, a very lightweight port without any pattern	291	Creates a new local port, and returns its ID. Semantically the same as
275	matching behind it, and returns its ID. Semantically the same as creating
276	a port and calling C<rcv $port, $callback> on it.	292	creating a port and calling C<rcv $port, $callback> on it.
277		293
278	The block will be called for every message received on the port. When the	294	The block will be called for every message received on the port, with the
279	callback returns a true value its job is considered "done" and the port	295	global variable C<$SELF> set to the port ID. Runtime errors will cause the
280	will be destroyed. Otherwise it will stay alive.	296	port to be C<kil>ed. The message will be passed as-is, no extra argument
		297	(i.e. no port ID) will be passed to the callback.
281		298
282	The message will be passed as-is, no extra argument (i.e. no port id) will	299	If you want to stop/destroy the port, simply C<kil> it:
283	be passed to the callback.
284		300
285	If you need the local port id in the callback, this works nicely:	301	my $port = port {
286		302	my @msg = @_;
287	my $port; $port = port {	303	...
288	snd $otherport, reply => $port;	304	kil $SELF;
289	};	305	};
290		306
291	=cut	307	=cut
292		308
293	sub rcv($@);	309	sub rcv($@);
		310
		311	sub _kilme {
		312	die "received message on port without callback";
		313	}
294		314
295	sub port(;&) {	315	sub port(;&) {
296	my $id = "$UNIQ." . $ID++;	316	my $id = "$UNIQ." . $ID++;
297	my $port = "$NODE#$id";	317	my $port = "$NODE#$id";
298		318
299	if (@_) {	319	rcv $port, shift \|\| \&_kilme;
300	rcv $port, shift;
301	} else {
302	$PORT{$id} = sub { }; # nop
303	}
304		320
305	$port	321	$port
306	}	322	}
307		323
308	=item reg $port, $name
309
310	=item reg $name
311
312	Registers the given port (or C<$SELF><<< if missing) under the name
313	C<$name>. If the name already exists it is replaced.
314
315	A port can only be registered under one well known name.
316
317	A port automatically becomes unregistered when it is killed.
318
319	=cut
320
321	sub reg(@) {
322	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
323
324	$REG{$_[0]} = $port;
325	}
326
327	=item rcv $port, $callback->(@msg)	324	=item rcv $local_port, $callback->(@msg)
328		325
329	Replaces the callback on the specified miniport (after converting it to	326	Replaces the default callback on the specified port. There is no way to
330	one if required).	327	remove the default callback: use C<sub { }> to disable it, or better
331		328	C<kil> the port when it is no longer needed.
332	=item rcv $port, tagstring => $callback->(@msg), ...
333
334	=item rcv $port, $smartmatch => $callback->(@msg), ...
335
336	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
337
338	Register callbacks to be called on matching messages on the given full
339	port (after converting it to one if required) and return the port.
340
341	The callback has to return a true value when its work is done, after
342	which is will be removed, or a false value in which case it will stay
343	registered.
344		329
345	The global C<$SELF> (exported by this module) contains C<$port> while	330	The global C<$SELF> (exported by this module) contains C<$port> while
346	executing the callback.	331	executing the callback. Runtime errors during callback execution will
		332	result in the port being C<kil>ed.
347		333
348	Runtime errors wdurign callback execution will result in the port being	334	The default callback received all messages not matched by a more specific
349	C<kil>ed.	335	C<tag> match.
350		336
351	If the match is an array reference, then it will be matched against the	337	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
352	first elements of the message, otherwise only the first element is being
353	matched.
354		338
355	Any element in the match that is specified as C<_any_> (a function	339	Register (or replace) callbacks to be called on messages starting with the
356	exported by this module) matches any single element of the message.	340	given tag on the given port (and return the port), or unregister it (when
		341	C<$callback> is C<$undef> or missing). There can only be one callback
		342	registered for each tag.
357		343
358	While not required, it is highly recommended that the first matching	344	The original message will be passed to the callback, after the first
359	element is a string identifying the message. The one-string-only match is	345	element (the tag) has been removed. The callback will use the same
360	also the most efficient match (by far).	346	environment as the default callback (see above).
361		347
362	Example: create a port and bind receivers on it in one go.	348	Example: create a port and bind receivers on it in one go.
363		349
364	my $port = rcv port,	350	my $port = rcv port,
365	msg1 => sub { ...; 0 },	351	msg1 => sub { ... },
366	msg2 => sub { ...; 0 },	352	msg2 => sub { ... },
367	;	353	;
368		354
369	Example: create a port, bind receivers and send it in a message elsewhere	355	Example: create a port, bind receivers and send it in a message elsewhere
370	in one go:	356	in one go:
371		357
372	snd $otherport, reply =>	358	snd $otherport, reply =>
373	rcv port,	359	rcv port,
374	msg1 => sub { ...; 0 },	360	msg1 => sub { ... },
375	...	361	...
376	;	362	;
		363
		364	Example: temporarily register a rcv callback for a tag matching some port
		365	(e.g. for a rpc reply) and unregister it after a message was received.
		366
		367	rcv $port, $otherport => sub {
		368	my @reply = @_;
		369
		370	rcv $SELF, $otherport;
		371	};
377		372
378	=cut	373	=cut
379		374
380	sub rcv($@) {	375	sub rcv($@) {
381	my $port = shift;	376	my $port = shift;
382	my ($noderef, $portid) = split /#/, $port, 2;	377	my ($noderef, $portid) = split /#/, $port, 2;
383		378
384	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	379	$NODE{$noderef} == $NODE{""}
385	or Carp::croak "$port: rcv can only be called on local ports, caught";	380	or Carp::croak "$port: rcv can only be called on local ports, caught";
386		381
387	if (@_ == 1) {	382	while (@_) {
		383	if (ref $_[0]) {
		384	if (my $self = $PORT_DATA{$portid}) {
		385	"AnyEvent::MP::Port" eq ref $self
		386	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		387
		388	$self->[2] = shift;
		389	} else {
388	my $cb = shift;	390	my $cb = shift;
389	delete $PORT_DATA{$portid};
390	$PORT{$portid} = sub {	391	$PORT{$portid} = sub {
391	local $SELF = $port;	392	local $SELF = $port;
392	eval {	393	eval { &$cb }; _self_die if $@;
393	&$cb	394	};
394	and kil $port;
395	};	395	}
396	_self_die if $@;	396	} elsif (defined $_[0]) {
397	};
398	} else {
399	my $self = $PORT_DATA{$portid} \|\|= do {	397	my $self = $PORT_DATA{$portid} \|\|= do {
400	my $self = bless {	398	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
401	id => $port,
402	}, "AnyEvent::MP::Port";
403		399
404	$PORT{$portid} = sub {	400	$PORT{$portid} = sub {
405	local $SELF = $port;	401	local $SELF = $port;
406		402
407	eval {
408	for (@{ $self->{rc0}{$_[0]} }) {	403	if (my $cb = $self->[1]{$_[0]}) {
409	$_ && &{$_->[0]}	404	shift;
410	&& undef $_;	405	eval { &$cb }; _self_die if $@;
411	}	406	} else {
412
413	for (@{ $self->{rcv}{$_[0]} }) {
414	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
415	&& &{$_->[0]}	407	&{ $self->[0] };
416	&& undef $_;
417	}
418
419	for (@{ $self->{any} }) {
420	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
421	&& &{$_->[0]}
422	&& undef $_;
423	}	408	}
424	};	409	};
425	_self_die if $@;	410
		411	$self
426	};	412	};
427		413
428	$self
429	};
430
431	"AnyEvent::MP::Port" eq ref $self	414	"AnyEvent::MP::Port" eq ref $self
432	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	415	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
433		416
434	while (@_) {
435	my ($match, $cb) = splice @_, 0, 2;	417	my ($tag, $cb) = splice @_, 0, 2;
436		418
437	if (!ref $match) {	419	if (defined $cb) {
438	push @{ $self->{rc0}{$match} }, [$cb];	420	$self->[1]{$tag} = $cb;
439	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
440	my ($type, @match) = @$match;
441	@match
442	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
443	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
444	} else {	421	} else {
445	push @{ $self->{any} }, [$cb, $match];	422	delete $self->[1]{$tag};
446	}	423	}
447	}	424	}
448	}	425	}
449		426
450	$port	427	$port
…		…
486	$res	463	$res
487	}	464	}
488	}	465	}
489	}	466	}
490		467
491	=item $guard = mon $port, $cb->(@reason)	468	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
492		469
493	=item $guard = mon $port, $rcvport	470	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
494		471
495	=item $guard = mon $port	472	=item $guard = mon $port # kill $SELF when $port dies
496		473
497	=item $guard = mon $port, $rcvport, @msg	474	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
498		475
499	Monitor the given port and do something when the port is killed, and	476	Monitor the given port and do something when the port is killed or
500	optionally return a guard that can be used to stop monitoring again.	477	messages to it were lost, and optionally return a guard that can be used
		478	to stop monitoring again.
		479
		480	C<mon> effectively guarantees that, in the absence of hardware failures,
		481	after starting the monitor, either all messages sent to the port will
		482	arrive, or the monitoring action will be invoked after possible message
		483	loss has been detected. No messages will be lost "in between" (after
		484	the first lost message no further messages will be received by the
		485	port). After the monitoring action was invoked, further messages might get
		486	delivered again.
		487
		488	Note that monitoring-actions are one-shot: once messages are lost (and a
		489	monitoring alert was raised), they are removed and will not trigger again.
501		490
502	In the first form (callback), the callback is simply called with any	491	In the first form (callback), the callback is simply called with any
503	number of C<@reason> elements (no @reason means that the port was deleted	492	number of C<@reason> elements (no @reason means that the port was deleted
504	"normally"). Note also that I<< the callback B<must> never die >>, so use	493	"normally"). Note also that I<< the callback B<must> never die >>, so use
505	C<eval> if unsure.	494	C<eval> if unsure.
506		495
507	In the second form (another port given), the other port (C<$rcvport)	496	In the second form (another port given), the other port (C<$rcvport>)
508	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	497	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
509	"normal" kils nothing happens, while under all other conditions, the other	498	"normal" kils nothing happens, while under all other conditions, the other
510	port is killed with the same reason.	499	port is killed with the same reason.
511		500
512	The third form (kill self) is the same as the second form, except that	501	The third form (kill self) is the same as the second form, except that
513	C<$rvport> defaults to C<$SELF>.	502	C<$rvport> defaults to C<$SELF>.
514		503
515	In the last form (message), a message of the form C<@msg, @reason> will be	504	In the last form (message), a message of the form C<@msg, @reason> will be
516	C<snd>.	505	C<snd>.
517		506
		507	As a rule of thumb, monitoring requests should always monitor a port from
		508	a local port (or callback). The reason is that kill messages might get
		509	lost, just like any other message. Another less obvious reason is that
		510	even monitoring requests can get lost (for exmaple, when the connection
		511	to the other node goes down permanently). When monitoring a port locally
		512	these problems do not exist.
		513
518	Example: call a given callback when C<$port> is killed.	514	Example: call a given callback when C<$port> is killed.
519		515
520	mon $port, sub { warn "port died because of <@_>\n" };	516	mon $port, sub { warn "port died because of <@_>\n" };
521		517
522	Example: kill ourselves when C<$port> is killed abnormally.	518	Example: kill ourselves when C<$port> is killed abnormally.
…		…
532	sub mon {	528	sub mon {
533	my ($noderef, $port) = split /#/, shift, 2;	529	my ($noderef, $port) = split /#/, shift, 2;
534		530
535	my $node = $NODE{$noderef} \|\| add_node $noderef;	531	my $node = $NODE{$noderef} \|\| add_node $noderef;
536		532
537	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	533	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
538		534
539	unless (ref $cb) {	535	unless (ref $cb) {
540	if (@_) {	536	if (@_) {
541	# send a kill info message	537	# send a kill info message
542	my (@msg) = @_;	538	my (@msg) = ($cb, @_);
543	$cb = sub { snd @msg, @_ };	539	$cb = sub { snd @msg, @_ };
544	} else {	540	} else {
545	# simply kill other port	541	# simply kill other port
546	my $port = $cb;	542	my $port = $cb;
547	$cb = sub { kil $port, @_ if @_ };	543	$cb = sub { kil $port, @_ if @_ };
…		…
560	is killed, the references will be freed.	556	is killed, the references will be freed.
561		557
562	Optionally returns a guard that will stop the monitoring.	558	Optionally returns a guard that will stop the monitoring.
563		559
564	This function is useful when you create e.g. timers or other watchers and	560	This function is useful when you create e.g. timers or other watchers and
565	want to free them when the port gets killed:	561	want to free them when the port gets killed (note the use of C<psub>):
566		562
567	$port->rcv (start => sub {	563	$port->rcv (start => sub {
568	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	564	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
569	undef $timer if 0.9 < rand;	565	undef $timer if 0.9 < rand;
570	});	566	});
571	});	567	});
572		568
573	=cut	569	=cut
…		…
578	#TODO: mon-less form?	574	#TODO: mon-less form?
579		575
580	mon $port, sub { 0 && @refs }	576	mon $port, sub { 0 && @refs }
581	}	577	}
582		578
583	=item lnk $port1, $port2
584
585	=item lnk $otherport
586
587	Link two ports. This is simply a shorthand for:
588
589	mon $port1, $port2;
590	mon $port2, $port1;
591
592	It means that if either one is killed abnormally, the other one gets
593	killed as well.
594
595	The one-argument form assumes that one port is C<$SELF>.
596
597	=cut
598
599	sub lnk {
600	my $port1 = shift;
601	my $port2 = @_ ? shift : $SELF \|\| Carp::croak 'lnk: called with one argument only, but $SELF not set,';
602
603	mon $port1, $port2;
604	mon $port2, $port1;
605	}
606
607	=item kil $port[, @reason]	579	=item kil $port[, @reason]
608		580
609	Kill the specified port with the given C<@reason>.	581	Kill the specified port with the given C<@reason>.
610		582
611	If no C<@reason> is specified, then the port is killed "normally" (linked	583	If no C<@reason> is specified, then the port is killed "normally" (ports
612	ports will not be kileld, or even notified).	584	monitoring other ports will not necessarily die because a port dies
		585	"normally").
613		586
614	Otherwise, linked ports get killed with the same reason (second form of	587	Otherwise, linked ports get killed with the same reason (second form of
615	C<mon>, see below).	588	C<mon>, see above).
616		589
617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	590	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
618	will be reported as reason C<< die => $@ >>.	591	will be reported as reason C<< die => $@ >>.
619		592
620	Transport/communication errors are reported as C<< transport_error =>	593	Transport/communication errors are reported as C<< transport_error =>
621	$message >>.	594	$message >>.
622		595
623	=back
624
625	=head1 NODE MESSAGES
626
627	Nodes understand the following messages sent to them. Many of them take
628	arguments called C<@reply>, which will simply be used to compose a reply
629	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
630	the remaining arguments are simply the message data.
631
632	While other messages exist, they are not public and subject to change.
633
634	=over 4
635
636	=cut	596	=cut
637		597
638	=item lookup => $name, @reply	598	=item $port = spawn $node, $initfunc[, @initdata]
639		599
640	Replies with the port ID of the specified well-known port, or C<undef>.	600	Creates a port on the node C<$node> (which can also be a port ID, in which
		601	case it's the node where that port resides).
641		602
642	=item devnull => ...	603	The port ID of the newly created port is returned immediately, and it is
		604	possible to immediately start sending messages or to monitor the port.
643		605
644	Generic data sink/CPU heat conversion.	606	After the port has been created, the init function is called on the remote
		607	node, in the same context as a C<rcv> callback. This function must be a
		608	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		609	specify a function in the main program, use C<::name>.
645		610
646	=item relay => $port, @msg	611	If the function doesn't exist, then the node tries to C<require>
		612	the package, then the package above the package and so on (e.g.
		613	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		614	exists or it runs out of package names.
647		615
648	Simply forwards the message to the given port.	616	The init function is then called with the newly-created port as context
		617	object (C<$SELF>) and the C<@initdata> values as arguments.
649		618
650	=item eval => $string[ @reply]	619	A common idiom is to pass a local port, immediately monitor the spawned
		620	port, and in the remote init function, immediately monitor the passed
		621	local port. This two-way monitoring ensures that both ports get cleaned up
		622	when there is a problem.
651		623
652	Evaluates the given string. If C<@reply> is given, then a message of the	624	Example: spawn a chat server port on C<$othernode>.
653	form C<@reply, $@, @evalres> is sent.
654		625
655	Example: crash another node.	626	# this node, executed from within a port context:
		627	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		628	mon $server;
656		629
657	snd $othernode, eval => "exit";	630	# init function on C<$othernode>
		631	sub connect {
		632	my ($srcport) = @_;
658		633
659	=item time => @reply	634	mon $srcport;
660		635
661	Replies the the current node time to C<@reply>.	636	rcv $SELF, sub {
		637	...
		638	};
		639	}
662		640
663	Example: tell the current node to send the current time to C<$myport> in a	641	=cut
664	C<timereply> message.
665		642
666	snd $NODE, time => $myport, timereply => 1, 2;	643	sub _spawn {
667	# => snd $myport, timereply => 1, 2, <time>	644	my $port = shift;
		645	my $init = shift;
		646
		647	local $SELF = "$NODE#$port";
		648	eval {
		649	&{ load_func $init }
		650	};
		651	_self_die if $@;
		652	}
		653
		654	sub spawn(@) {
		655	my ($noderef, undef) = split /#/, shift, 2;
		656
		657	my $id = "$RUNIQ." . $ID++;
		658
		659	$_[0] =~ /::/
		660	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		661
		662	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
		663
		664	"$noderef#$id"
		665	}
		666
		667	=item after $timeout, @msg
		668
		669	=item after $timeout, $callback
		670
		671	Either sends the given message, or call the given callback, after the
		672	specified number of seconds.
		673
		674	This is simply a utility function that comes in handy at times - the
		675	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		676	so it may go away in the future.
		677
		678	=cut
		679
		680	sub after($@) {
		681	my ($timeout, @action) = @_;
		682
		683	my $t; $t = AE::timer $timeout, 0, sub {
		684	undef $t;
		685	ref $action[0]
		686	? $action[0]()
		687	: snd @action;
		688	};
		689	}
668		690
669	=back	691	=back
670		692
671	=head1 AnyEvent::MP vs. Distributed Erlang	693	=head1 AnyEvent::MP vs. Distributed Erlang
672		694
…		…
682		704
683	Despite the similarities, there are also some important differences:	705	Despite the similarities, there are also some important differences:
684		706
685	=over 4	707	=over 4
686		708
687	=item * Node references contain the recipe on how to contact them.	709	=item * Node IDs are arbitrary strings in AEMP.
688		710
689	Erlang relies on special naming and DNS to work everywhere in the	711	Erlang relies on special naming and DNS to work everywhere in the same
690	same way. AEMP relies on each node knowing it's own address(es), with	712	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
691	convenience functionality.	713	configuraiton or DNS), but will otherwise discover other odes itself.
692		714
693	This means that AEMP requires a less tightly controlled environment at the	715	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
694	cost of longer node references and a slightly higher management overhead.	716	uses "local ports are like remote ports".
		717
		718	The failure modes for local ports are quite different (runtime errors
		719	only) then for remote ports - when a local port dies, you I<know> it dies,
		720	when a connection to another node dies, you know nothing about the other
		721	port.
		722
		723	Erlang pretends remote ports are as reliable as local ports, even when
		724	they are not.
		725
		726	AEMP encourages a "treat remote ports differently" philosophy, with local
		727	ports being the special case/exception, where transport errors cannot
		728	occur.
695		729
696	=item * Erlang uses processes and a mailbox, AEMP does not queue.	730	=item * Erlang uses processes and a mailbox, AEMP does not queue.
697		731
698	Erlang uses processes that selctively receive messages, and therefore	732	Erlang uses processes that selectively receive messages, and therefore
699	needs a queue. AEMP is event based, queuing messages would serve no useful	733	needs a queue. AEMP is event based, queuing messages would serve no
700	purpose.	734	useful purpose. For the same reason the pattern-matching abilities of
		735	AnyEvent::MP are more limited, as there is little need to be able to
		736	filter messages without dequeing them.
701		737
702	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	738	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
703		739
704	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	740	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
705		741
706	Sending messages in Erlang is synchronous and blocks the process. AEMP	742	Sending messages in Erlang is synchronous and blocks the process (and
707	sends are immediate, connection establishment is handled in the	743	so does not need a queue that can overflow). AEMP sends are immediate,
708	background.	744	connection establishment is handled in the background.
709		745
710	=item * Erlang can silently lose messages, AEMP cannot.	746	=item * Erlang suffers from silent message loss, AEMP does not.
711		747
712	Erlang makes few guarantees on messages delivery - messages can get lost	748	Erlang makes few guarantees on messages delivery - messages can get lost
713	without any of the processes realising it (i.e. you send messages a, b,	749	without any of the processes realising it (i.e. you send messages a, b,
714	and c, and the other side only receives messages a and c).	750	and c, and the other side only receives messages a and c).
715		751
716	AEMP guarantees correct ordering, and the guarantee that there are no	752	AEMP guarantees correct ordering, and the guarantee that after one message
717	holes in the message sequence.	753	is lost, all following ones sent to the same port are lost as well, until
718		754	monitoring raises an error, so there are no silent "holes" in the message
719	=item * In Erlang, processes can be declared dead and later be found to be	755	sequence.
720	alive.
721
722	In Erlang it can happen that a monitored process is declared dead and
723	linked processes get killed, but later it turns out that the process is
724	still alive - and can receive messages.
725
726	In AEMP, when port monitoring detects a port as dead, then that port will
727	eventually be killed - it cannot happen that a node detects a port as dead
728	and then later sends messages to it, finding it is still alive.
729		756
730	=item * Erlang can send messages to the wrong port, AEMP does not.	757	=item * Erlang can send messages to the wrong port, AEMP does not.
731		758
732	In Erlang it is quite possible that a node that restarts reuses a process	759	In Erlang it is quite likely that a node that restarts reuses a process ID
733	ID known to other nodes for a completely different process, causing	760	known to other nodes for a completely different process, causing messages
734	messages destined for that process to end up in an unrelated process.	761	destined for that process to end up in an unrelated process.
735		762
736	AEMP never reuses port IDs, so old messages or old port IDs floating	763	AEMP never reuses port IDs, so old messages or old port IDs floating
737	around in the network will not be sent to an unrelated port.	764	around in the network will not be sent to an unrelated port.
738		765
739	=item * Erlang uses unprotected connections, AEMP uses secure	766	=item * Erlang uses unprotected connections, AEMP uses secure
740	authentication and can use TLS.	767	authentication and can use TLS.
741		768
742	AEMP can use a proven protocol - SSL/TLS - to protect connections and	769	AEMP can use a proven protocol - TLS - to protect connections and
743	securely authenticate nodes.	770	securely authenticate nodes.
744		771
745	=item * The AEMP protocol is optimised for both text-based and binary	772	=item * The AEMP protocol is optimised for both text-based and binary
746	communications.	773	communications.
747		774
748	The AEMP protocol, unlike the Erlang protocol, supports both	775	The AEMP protocol, unlike the Erlang protocol, supports both programming
749	language-independent text-only protocols (good for debugging) and binary,	776	language independent text-only protocols (good for debugging) and binary,
750	language-specific serialisers (e.g. Storable).	777	language-specific serialisers (e.g. Storable). By default, unless TLS is
		778	used, the protocol is actually completely text-based.
751		779
752	It has also been carefully designed to be implementable in other languages	780	It has also been carefully designed to be implementable in other languages
753	with a minimum of work while gracefully degrading fucntionality to make the	781	with a minimum of work while gracefully degrading functionality to make the
754	protocol simple.	782	protocol simple.
755		783
756	=item * AEMP has more flexible monitoring options than Erlang.	784	=item * AEMP has more flexible monitoring options than Erlang.
757		785
758	In Erlang, you can chose to receive I<all> exit signals as messages	786	In Erlang, you can chose to receive I<all> exit signals as messages
759	or I<none>, there is no in-between, so monitoring single processes is	787	or I<none>, there is no in-between, so monitoring single processes is
760	difficult to implement. Monitoring in AEMP is more flexible than in	788	difficult to implement. Monitoring in AEMP is more flexible than in
761	Erlang, as one can choose between automatic kill, exit message or callback	789	Erlang, as one can choose between automatic kill, exit message or callback
762	on a per-process basis.	790	on a per-process basis.
763		791
764	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.	792	=item * Erlang tries to hide remote/local connections, AEMP does not.
765		793
766	Monitoring in Erlang is not an indicator of process death/crashes,	794	Monitoring in Erlang is not an indicator of process death/crashes, in the
767	as linking is (except linking is unreliable in Erlang). In AEMP, the	795	same way as linking is (except linking is unreliable in Erlang).
768	semantics of monitoring and linking are identical, linking is simply	796
769	two-way monitoring with automatic kill.	797	In AEMP, you don't "look up" registered port names or send to named ports
		798	that might or might not be persistent. Instead, you normally spawn a port
		799	on the remote node. The init function monitors you, and you monitor the
		800	remote port. Since both monitors are local to the node, they are much more
		801	reliable (no need for C<spawn_link>).
		802
		803	This also saves round-trips and avoids sending messages to the wrong port
		804	(hard to do in Erlang).
770		805
771	=back	806	=back
772		807
		808	=head1 RATIONALE
		809
		810	=over 4
		811
		812	=item Why strings for port and node IDs, why not objects?
		813
		814	We considered "objects", but found that the actual number of methods
		815	that can be called are quite low. Since port and node IDs travel over
		816	the network frequently, the serialising/deserialising would add lots of
		817	overhead, as well as having to keep a proxy object everywhere.
		818
		819	Strings can easily be printed, easily serialised etc. and need no special
		820	procedures to be "valid".
		821
		822	And as a result, a miniport consists of a single closure stored in a
		823	global hash - it can't become much cheaper.
		824
		825	=item Why favour JSON, why not a real serialising format such as Storable?
		826
		827	In fact, any AnyEvent::MP node will happily accept Storable as framing
		828	format, but currently there is no way to make a node use Storable by
		829	default (although all nodes will accept it).
		830
		831	The default framing protocol is JSON because a) JSON::XS is many times
		832	faster for small messages and b) most importantly, after years of
		833	experience we found that object serialisation is causing more problems
		834	than it solves: Just like function calls, objects simply do not travel
		835	easily over the network, mostly because they will always be a copy, so you
		836	always have to re-think your design.
		837
		838	Keeping your messages simple, concentrating on data structures rather than
		839	objects, will keep your messages clean, tidy and efficient.
		840
		841	=back
		842
773	=head1 SEE ALSO	843	=head1 SEE ALSO
		844
		845	L<AnyEvent::MP::Intro> - a gentle introduction.
		846
		847	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		848
		849	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		850	your applications.
774		851
775	L<AnyEvent>.	852	L<AnyEvent>.
776		853
777	=head1 AUTHOR	854	=head1 AUTHOR
778		855

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs. Revision 1.74 by root, Mon Aug 31 11:11:27 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs.
Revision 1.74 by root, Mon Aug 31 11:11:27 2009 UTC