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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs.
Revision 1.71 by root, Sun Aug 30 19:52:56 2009 UTC

…		…
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	13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node;
14		17
15	# ports are message endpoints	18	# ports are message endpoints
16		19
17	# sending messages	20	# sending messages
18	snd $port, type => data...;	21	snd $port, type => data...;
19	snd $port, @msg;	22	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
21		24
22	# miniports	25	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
24		27
25	# full ports	28	# creating/using ports, tagged message matching
26	my $port = port;	29	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		32
31	# remote ports	33	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	34	my $port = spawn $node, $initfunc, @initdata;
33
34	# more, smarter, matches (_any_ is exported by this module)
35	rcv $port, [child_died => $pid] => sub { ...
36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
37		35
38	# monitoring	36	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	37	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	38	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	39	mon $port, $otherport, @msg # send message on death
42		40
43	=head1 CURRENT STATUS	41	=head1 CURRENT STATUS
44		42
		43	bin/aemp - stable.
45	AnyEvent::MP - stable API, should work	44	AnyEvent::MP - stable API, should work.
46	AnyEvent::MP::Intro - outdated	45	AnyEvent::MP::Intro - uptodate, but incomplete.
47	AnyEvent::MP::Kernel - WIP
48	AnyEvent::MP::Transport - mostly stable	46	AnyEvent::MP::Kernel - mostly stable.
		47	AnyEvent::MP::Global - stable API, protocol not yet final.
49		48
50	stay tuned.	49	stay tuned.
51		50
52	=head1 DESCRIPTION	51	=head1 DESCRIPTION
53		52
54	This module (-family) implements a simple message passing framework.	53	This module (-family) implements a simple message passing framework.
55		54
56	Despite its simplicity, you can securely message other processes running	55	Despite its simplicity, you can securely message other processes running
57	on the same or other hosts.	56	on the same or other hosts, and you can supervise entities remotely.
58		57
59	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>
60	manual page.	59	manual page and the examples under F<eg/>.
61		60
62	At the moment, this module family is severly broken and underdocumented,	61	At the moment, this module family is a bit underdocumented.
63	so do not use. This was uploaded mainly to reserve the CPAN namespace -
64	stay tuned!
65		62
66	=head1 CONCEPTS	63	=head1 CONCEPTS
67		64
68	=over 4	65	=over 4
69		66
70	=item port	67	=item port
71		68
72	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).
73		70
74	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
75	messages. All C<rcv> handlers will receive messages they match, messages	72	some messages. Messages send to ports will not be queued, regardless of
76	will not be queued.	73	anything was listening for them or not.
77		74
78	=item port id - C<noderef#portname>	75	=item port ID - C<nodeid#portname>
79		76
80	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
81	separator, and a port name (a printable string of unspecified format). An	78	separator, and a port name (a printable string of unspecified format).
82	exception is the the node port, whose ID is identical to its node
83	reference.
84		79
85	=item node	80	=item node
86		81
87	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,
88	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
89	create new ports, among other things.	84	ports.
90		85
91	Nodes are either private (single-process only), slaves (connected to a	86	Nodes are either public (have one or more listening ports) or private
92	master node only) or public nodes (connectable from unrelated nodes).	87	(no listening ports). Private nodes cannot talk to other private nodes
		88	currently.
93		89
94	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	90	=item node ID - C<[a-za-Z0-9_\-.:]+>
95		91
96	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
97	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
98	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.
99		96
100	This recipe is simply a comma-separated list of C<address:port> pairs (for	97	=item binds - C<ip:port>
101	TCP/IP, other protocols might look different).
102		98
103	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
104	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.
105		103
106	Before using an unresolved node reference in a message you first have to	104	=item seeds - C<host:port>
107	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.
108		118
109	=back	119	=back
110		120
111	=head1 VARIABLES/FUNCTIONS	121	=head1 VARIABLES/FUNCTIONS
112		122
…		…
127	use base "Exporter";	137	use base "Exporter";
128		138
129	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	139	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
130		140
131	our @EXPORT = qw(	141	our @EXPORT = qw(
132	NODE $NODE *SELF node_of _any_	142	NODE $NODE *SELF node_of after
133	resolve_node initialise_node	143	initialise_node
134	snd rcv mon kil reg psub spawn	144	snd rcv mon mon_guard kil reg psub spawn
135	port	145	port
136	);	146	);
137		147
138	our $SELF;	148	our $SELF;
139		149
…		…
143	kil $SELF, die => $msg;	153	kil $SELF, die => $msg;
144	}	154	}
145		155
146	=item $thisnode = NODE / $NODE	156	=item $thisnode = NODE / $NODE
147		157
148	The C<NODE> function returns, and the C<$NODE> variable contains	158	The C<NODE> function returns, and the C<$NODE> variable contains, the node
149	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
150	to C<become_public> or C<become_slave>, after which all local port	160	a call to C<initialise_node>.
151	identifiers become invalid.
152		161
153	=item $noderef = node_of $port	162	=item $nodeid = node_of $port
154		163
155	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.
156		165
157	=item initialise_node $noderef, $seednode, $seednode...	166	=item initialise_node $profile_name, key => value...
158		167
159	=item initialise_node "slave/", $master, $master...
160
161	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
162	itself - the minimum a node needs to know is it's own name, and optionally	169	"distributed mode") it has to initialise itself - the minimum a node needs
163	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.
164		172
165	This function initialises a node - it must be called exactly once (or	173	This function initialises a node - it must be called exactly once (or
166	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
167		175
168	All arguments are noderefs, which can be either resolved or unresolved.	176	The first argument is a profile name. If it is C<undef> or missing, then
		177	the current nodename will be used instead (i.e. F<uname -n>).
169		178
170	There are two types of networked nodes, public nodes and slave nodes:	179	The function first looks up the profile in the aemp configuration (see the
		180	L<aemp> commandline utility). the profile is calculated as follows:
171		181
172	=over 4	182	First, all remaining key => value pairs (all of which are conviniently
		183	undocumented at the moment) will be used. Then they will be overwritten by
		184	any values specified in the global default configuration (see the F<aemp>
		185	utility), then the chain of profiles selected, if any. That means that
		186	the values specified in the profile have highest priority and the values
		187	specified via C<initialise_node> have lowest priority.
173		188
174	=item public nodes	189	If the profile specifies a node ID, then this will become the node ID of
		190	this process. If not, then the profile name will be used as node ID. The
		191	special node ID of C<anon/> will be replaced by a random node ID.
175		192
176	For public nodes, C<$noderef> must either be a (possibly unresolved)	193	The next step is to look up the binds in the profile, followed by binding
177	noderef, in which case it will be resolved, or C<undef> (or missing), in	194	aemp protocol listeners on all binds specified (it is possible and valid
178	which case the noderef will be guessed.	195	to have no binds, meaning that the node cannot be contacted form the
		196	outside. This means the node cannot talk to other nodes that also have no
		197	binds, but it can still talk to all "normal" nodes).
179		198
180	Afterwards, the node will bind itself on all endpoints and try to connect	199	If the profile does not specify a binds list, then a default of C<*> is
181	to all additional C<$seednodes> that are specified. Seednodes are optional	200	used.
182	and can be used to quickly bootstrap the node into an existing network.
183		201
184	=item slave nodes	202	Lastly, the seeds list from the profile is passed to the
		203	L<AnyEvent::MP::Global> module, which will then use it to keep
		204	connectivity with at least on of those seed nodes at any point in time.
185		205
186	When the C<$noderef> is the special string C<slave/>, then the node will	206	Example: become a distributed node listening on the guessed noderef, or
187	become a slave node. Slave nodes cannot be contacted from outside and will	207	the one specified via C<aemp> for the current node. This should be the
188	route most of their traffic to the master node that they attach to.	208	most common form of invocation for "daemon"-type nodes.
189
190	At least one additional noderef is required: The node will try to connect
191	to all of them and will become a slave attached to the first node it can
192	successfully connect to.
193
194	=back
195
196	This function will block until all nodes have been resolved and, for slave
197	nodes, until it has successfully established a connection to a master
198	server.
199
200	Example: become a public node listening on the default node.
201		209
202	initialise_node;	210	initialise_node;
203		211
204	Example: become a public node, and try to contact some well-known master	212	Example: become an anonymous node. This form is often used for commandline
205	servers to become part of the network.	213	clients.
206		214
207	initialise_node undef, "master1", "master2";
208
209	Example: become a public node listening on port C<4041>.
210
211	initialise_node 4041;	215	initialise_node "anon/";
212		216
213	Example: become a public node, only visible on localhost port 4044.	217	Example: become a distributed node. If there is no profile of the given
		218	name, or no binds list was specified, resolve C<localhost:4044> and bind
		219	on the resulting addresses.
214		220
215	initialise_node "locahost:4044";	221	initialise_node "localhost:4044";
216
217	Example: become a slave node to any of the specified master servers.
218
219	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
220
221	=item $cv = resolve_node $noderef
222
223	Takes an unresolved node reference that may contain hostnames and
224	abbreviated IDs, resolves all of them and returns a resolved node
225	reference.
226
227	In addition to C<address:port> pairs allowed in resolved noderefs, the
228	following forms are supported:
229
230	=over 4
231
232	=item the empty string
233
234	An empty-string component gets resolved as if the default port (4040) was
235	specified.
236
237	=item naked port numbers (e.g. C<1234>)
238
239	These are resolved by prepending the local nodename and a colon, to be
240	further resolved.
241
242	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
243
244	These are resolved by using AnyEvent::DNS to resolve them, optionally
245	looking up SRV records for the C<aemp=4040> port, if no port was
246	specified.
247
248	=back
249		222
250	=item $SELF	223	=item $SELF
251		224
252	Contains the current port id while executing C<rcv> callbacks or C<psub>	225	Contains the current port id while executing C<rcv> callbacks or C<psub>
253	blocks.	226	blocks.
254		227
255	=item SELF, %SELF, @SELF...	228	=item *SELF, SELF, %SELF, @SELF...
256		229
257	Due to some quirks in how perl exports variables, it is impossible to	230	Due to some quirks in how perl exports variables, it is impossible to
258	just export C<$SELF>, all the symbols called C<SELF> are exported by this	231	just export C<$SELF>, all the symbols named C<SELF> are exported by this
259	module, but only C<$SELF> is currently used.	232	module, but only C<$SELF> is currently used.
260		233
261	=item snd $port, type => @data	234	=item snd $port, type => @data
262		235
263	=item snd $port, @msg	236	=item snd $port, @msg
264		237
265	Send the given message to the given port ID, which can identify either	238	Send the given message to the given port, which can identify either a
266	a local or a remote port, and can be either a string or soemthignt hat	239	local or a remote port, and must be a port ID.
267	stringifies a sa port ID (such as a port object :).
268		240
269	While the message can be about anything, it is highly recommended to use a	241	While the message can be almost anything, it is highly recommended to
270	string as first element (a portid, or some word that indicates a request	242	use a string as first element (a port ID, or some word that indicates a
271	type etc.).	243	request type etc.) and to consist if only simple perl values (scalars,
		244	arrays, hashes) - if you think you need to pass an object, think again.
272		245
273	The message data effectively becomes read-only after a call to this	246	The message data logically becomes read-only after a call to this
274	function: modifying any argument is not allowed and can cause many	247	function: modifying any argument (or values referenced by them) is
275	problems.	248	forbidden, as there can be considerable time between the call to C<snd>
		249	and the time the message is actually being serialised - in fact, it might
		250	never be copied as within the same process it is simply handed to the
		251	receiving port.
276		252
277	The type of data you can transfer depends on the transport protocol: when	253	The type of data you can transfer depends on the transport protocol: when
278	JSON is used, then only strings, numbers and arrays and hashes consisting	254	JSON is used, then only strings, numbers and arrays and hashes consisting
279	of those are allowed (no objects). When Storable is used, then anything	255	of those are allowed (no objects). When Storable is used, then anything
280	that Storable can serialise and deserialise is allowed, and for the local	256	that Storable can serialise and deserialise is allowed, and for the local
281	node, anything can be passed.	257	node, anything can be passed. Best rely only on the common denominator of
		258	these.
282		259
283	=item $local_port = port	260	=item $local_port = port
284		261
285	Create a new local port object that can be used either as a pattern	262	Create a new local port object and returns its port ID. Initially it has
286	matching port ("full port") or a single-callback port ("miniport"),	263	no callbacks set and will throw an error when it receives messages.
287	depending on how C<rcv> callbacks are bound to the object.
288		264
289	=item $port = port { my @msg = @_; $finished }	265	=item $local_port = port { my @msg = @_ }
290		266
291	Creates a "miniport", that is, a very lightweight port without any pattern	267	Creates a new local port, and returns its ID. Semantically the same as
292	matching behind it, and returns its ID. Semantically the same as creating
293	a port and calling C<rcv $port, $callback> on it.	268	creating a port and calling C<rcv $port, $callback> on it.
294		269
295	The block will be called for every message received on the port. When the	270	The block will be called for every message received on the port, with the
296	callback returns a true value its job is considered "done" and the port	271	global variable C<$SELF> set to the port ID. Runtime errors will cause the
297	will be destroyed. Otherwise it will stay alive.	272	port to be C<kil>ed. The message will be passed as-is, no extra argument
		273	(i.e. no port ID) will be passed to the callback.
298		274
299	The message will be passed as-is, no extra argument (i.e. no port id) will	275	If you want to stop/destroy the port, simply C<kil> it:
300	be passed to the callback.
301		276
302	If you need the local port id in the callback, this works nicely:	277	my $port = port {
303		278	my @msg = @_;
304	my $port; $port = port {	279	...
305	snd $otherport, reply => $port;	280	kil $SELF;
306	};	281	};
307		282
308	=cut	283	=cut
309		284
310	sub rcv($@);	285	sub rcv($@);
		286
		287	sub _kilme {
		288	die "received message on port without callback";
		289	}
311		290
312	sub port(;&) {	291	sub port(;&) {
313	my $id = "$UNIQ." . $ID++;	292	my $id = "$UNIQ." . $ID++;
314	my $port = "$NODE#$id";	293	my $port = "$NODE#$id";
315		294
316	if (@_) {	295	rcv $port, shift \|\| \&_kilme;
317	rcv $port, shift;
318	} else {
319	$PORT{$id} = sub { }; # nop
320	}
321		296
322	$port	297	$port
323	}	298	}
324		299
325	=item reg $port, $name
326
327	=item reg $name
328
329	Registers the given port (or C<$SELF><<< if missing) under the name
330	C<$name>. If the name already exists it is replaced.
331
332	A port can only be registered under one well known name.
333
334	A port automatically becomes unregistered when it is killed.
335
336	=cut
337
338	sub reg(@) {
339	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
340
341	$REG{$_[0]} = $port;
342	}
343
344	=item rcv $port, $callback->(@msg)	300	=item rcv $local_port, $callback->(@msg)
345		301
346	Replaces the callback on the specified miniport (after converting it to	302	Replaces the default callback on the specified port. There is no way to
347	one if required).	303	remove the default callback: use C<sub { }> to disable it, or better
348		304	C<kil> the port when it is no longer needed.
349	=item rcv $port, tagstring => $callback->(@msg), ...
350
351	=item rcv $port, $smartmatch => $callback->(@msg), ...
352
353	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
354
355	Register callbacks to be called on matching messages on the given full
356	port (after converting it to one if required) and return the port.
357
358	The callback has to return a true value when its work is done, after
359	which is will be removed, or a false value in which case it will stay
360	registered.
361		305
362	The global C<$SELF> (exported by this module) contains C<$port> while	306	The global C<$SELF> (exported by this module) contains C<$port> while
363	executing the callback.	307	executing the callback. Runtime errors during callback execution will
		308	result in the port being C<kil>ed.
364		309
365	Runtime errors during callback execution will result in the port being	310	The default callback received all messages not matched by a more specific
366	C<kil>ed.	311	C<tag> match.
367		312
368	If the match is an array reference, then it will be matched against the	313	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
369	first elements of the message, otherwise only the first element is being
370	matched.
371		314
372	Any element in the match that is specified as C<_any_> (a function	315	Register (or replace) callbacks to be called on messages starting with the
373	exported by this module) matches any single element of the message.	316	given tag on the given port (and return the port), or unregister it (when
		317	C<$callback> is C<$undef> or missing). There can only be one callback
		318	registered for each tag.
374		319
375	While not required, it is highly recommended that the first matching	320	The original message will be passed to the callback, after the first
376	element is a string identifying the message. The one-string-only match is	321	element (the tag) has been removed. The callback will use the same
377	also the most efficient match (by far).	322	environment as the default callback (see above).
378		323
379	Example: create a port and bind receivers on it in one go.	324	Example: create a port and bind receivers on it in one go.
380		325
381	my $port = rcv port,	326	my $port = rcv port,
382	msg1 => sub { ...; 0 },	327	msg1 => sub { ... },
383	msg2 => sub { ...; 0 },	328	msg2 => sub { ... },
384	;	329	;
385		330
386	Example: create a port, bind receivers and send it in a message elsewhere	331	Example: create a port, bind receivers and send it in a message elsewhere
387	in one go:	332	in one go:
388		333
389	snd $otherport, reply =>	334	snd $otherport, reply =>
390	rcv port,	335	rcv port,
391	msg1 => sub { ...; 0 },	336	msg1 => sub { ... },
392	...	337	...
393	;	338	;
		339
		340	Example: temporarily register a rcv callback for a tag matching some port
		341	(e.g. for a rpc reply) and unregister it after a message was received.
		342
		343	rcv $port, $otherport => sub {
		344	my @reply = @_;
		345
		346	rcv $SELF, $otherport;
		347	};
394		348
395	=cut	349	=cut
396		350
397	sub rcv($@) {	351	sub rcv($@) {
398	my $port = shift;	352	my $port = shift;
399	my ($noderef, $portid) = split /#/, $port, 2;	353	my ($noderef, $portid) = split /#/, $port, 2;
400		354
401	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	355	$NODE{$noderef} == $NODE{""}
402	or Carp::croak "$port: rcv can only be called on local ports, caught";	356	or Carp::croak "$port: rcv can only be called on local ports, caught";
403		357
404	if (@_ == 1) {	358	while (@_) {
		359	if (ref $_[0]) {
		360	if (my $self = $PORT_DATA{$portid}) {
		361	"AnyEvent::MP::Port" eq ref $self
		362	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		363
		364	$self->[2] = shift;
		365	} else {
405	my $cb = shift;	366	my $cb = shift;
406	delete $PORT_DATA{$portid};
407	$PORT{$portid} = sub {	367	$PORT{$portid} = sub {
408	local $SELF = $port;	368	local $SELF = $port;
409	eval {	369	eval { &$cb }; _self_die if $@;
410	&$cb	370	};
411	and kil $port;
412	};	371	}
413	_self_die if $@;	372	} elsif (defined $_[0]) {
414	};
415	} else {
416	my $self = $PORT_DATA{$portid} \|\|= do {	373	my $self = $PORT_DATA{$portid} \|\|= do {
417	my $self = bless {	374	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
418	id => $port,
419	}, "AnyEvent::MP::Port";
420		375
421	$PORT{$portid} = sub {	376	$PORT{$portid} = sub {
422	local $SELF = $port;	377	local $SELF = $port;
423		378
424	eval {
425	for (@{ $self->{rc0}{$_[0]} }) {	379	if (my $cb = $self->[1]{$_[0]}) {
426	$_ && &{$_->[0]}	380	shift;
427	&& undef $_;	381	eval { &$cb }; _self_die if $@;
428	}	382	} else {
429
430	for (@{ $self->{rcv}{$_[0]} }) {
431	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
432	&& &{$_->[0]}	383	&{ $self->[0] };
433	&& undef $_;
434	}
435
436	for (@{ $self->{any} }) {
437	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
438	&& &{$_->[0]}
439	&& undef $_;
440	}	384	}
441	};	385	};
442	_self_die if $@;	386
		387	$self
443	};	388	};
444		389
445	$self
446	};
447
448	"AnyEvent::MP::Port" eq ref $self	390	"AnyEvent::MP::Port" eq ref $self
449	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	391	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
450		392
451	while (@_) {
452	my ($match, $cb) = splice @_, 0, 2;	393	my ($tag, $cb) = splice @_, 0, 2;
453		394
454	if (!ref $match) {	395	if (defined $cb) {
455	push @{ $self->{rc0}{$match} }, [$cb];	396	$self->[1]{$tag} = $cb;
456	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
457	my ($type, @match) = @$match;
458	@match
459	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
460	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
461	} else {	397	} else {
462	push @{ $self->{any} }, [$cb, $match];	398	delete $self->[1]{$tag};
463	}	399	}
464	}	400	}
465	}	401	}
466		402
467	$port	403	$port
…		…
503	$res	439	$res
504	}	440	}
505	}	441	}
506	}	442	}
507		443
508	=item $guard = mon $port, $cb->(@reason)	444	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
509		445
510	=item $guard = mon $port, $rcvport	446	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
511		447
512	=item $guard = mon $port	448	=item $guard = mon $port # kill $SELF when $port dies
513		449
514	=item $guard = mon $port, $rcvport, @msg	450	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
515		451
516	Monitor the given port and do something when the port is killed or	452	Monitor the given port and do something when the port is killed or
517	messages to it were lost, and optionally return a guard that can be used	453	messages to it were lost, and optionally return a guard that can be used
518	to stop monitoring again.	454	to stop monitoring again.
519		455
520	C<mon> effectively guarantees that, in the absence of hardware failures,	456	C<mon> effectively guarantees that, in the absence of hardware failures,
521	that after starting the monitor, either all messages sent to the port	457	after starting the monitor, either all messages sent to the port will
522	will arrive, or the monitoring action will be invoked after possible	458	arrive, or the monitoring action will be invoked after possible message
523	message loss has been detected. No messages will be lost "in between"	459	loss has been detected. No messages will be lost "in between" (after
524	(after the first lost message no further messages will be received by the	460	the first lost message no further messages will be received by the
525	port). After the monitoring action was invoked, further messages might get	461	port). After the monitoring action was invoked, further messages might get
526	delivered again.	462	delivered again.
		463
		464	Note that monitoring-actions are one-shot: once messages are lost (and a
		465	monitoring alert was raised), they are removed and will not trigger again.
527		466
528	In the first form (callback), the callback is simply called with any	467	In the first form (callback), the callback is simply called with any
529	number of C<@reason> elements (no @reason means that the port was deleted	468	number of C<@reason> elements (no @reason means that the port was deleted
530	"normally"). Note also that I<< the callback B<must> never die >>, so use	469	"normally"). Note also that I<< the callback B<must> never die >>, so use
531	C<eval> if unsure.	470	C<eval> if unsure.
…		…
593	is killed, the references will be freed.	532	is killed, the references will be freed.
594		533
595	Optionally returns a guard that will stop the monitoring.	534	Optionally returns a guard that will stop the monitoring.
596		535
597	This function is useful when you create e.g. timers or other watchers and	536	This function is useful when you create e.g. timers or other watchers and
598	want to free them when the port gets killed:	537	want to free them when the port gets killed (note the use of C<psub>):
599		538
600	$port->rcv (start => sub {	539	$port->rcv (start => sub {
601	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	540	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
602	undef $timer if 0.9 < rand;	541	undef $timer if 0.9 < rand;
603	});	542	});
604	});	543	});
605		544
606	=cut	545	=cut
…		…
615		554
616	=item kil $port[, @reason]	555	=item kil $port[, @reason]
617		556
618	Kill the specified port with the given C<@reason>.	557	Kill the specified port with the given C<@reason>.
619		558
620	If no C<@reason> is specified, then the port is killed "normally" (linked	559	If no C<@reason> is specified, then the port is killed "normally" (ports
621	ports will not be kileld, or even notified).	560	monitoring other ports will not necessarily die because a port dies
		561	"normally").
622		562
623	Otherwise, linked ports get killed with the same reason (second form of	563	Otherwise, linked ports get killed with the same reason (second form of
624	C<mon>, see below).	564	C<mon>, see above).
625		565
626	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	566	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
627	will be reported as reason C<< die => $@ >>.	567	will be reported as reason C<< die => $@ >>.
628		568
629	Transport/communication errors are reported as C<< transport_error =>	569	Transport/communication errors are reported as C<< transport_error =>
…		…
634	=item $port = spawn $node, $initfunc[, @initdata]	574	=item $port = spawn $node, $initfunc[, @initdata]
635		575
636	Creates a port on the node C<$node> (which can also be a port ID, in which	576	Creates a port on the node C<$node> (which can also be a port ID, in which
637	case it's the node where that port resides).	577	case it's the node where that port resides).
638		578
639	The port ID of the newly created port is return immediately, and it is	579	The port ID of the newly created port is returned immediately, and it is
640	permissible to immediately start sending messages or monitor the port.	580	possible to immediately start sending messages or to monitor the port.
641		581
642	After the port has been created, the init function is	582	After the port has been created, the init function is called on the remote
643	called. This function must be a fully-qualified function name	583	node, in the same context as a C<rcv> callback. This function must be a
644	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	584	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
645	program, use C<::name>.	585	specify a function in the main program, use C<::name>.
646		586
647	If the function doesn't exist, then the node tries to C<require>	587	If the function doesn't exist, then the node tries to C<require>
648	the package, then the package above the package and so on (e.g.	588	the package, then the package above the package and so on (e.g.
649	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	589	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
650	exists or it runs out of package names.	590	exists or it runs out of package names.
651		591
652	The init function is then called with the newly-created port as context	592	The init function is then called with the newly-created port as context
653	object (C<$SELF>) and the C<@initdata> values as arguments.	593	object (C<$SELF>) and the C<@initdata> values as arguments.
654		594
655	A common idiom is to pass your own port, monitor the spawned port, and	595	A common idiom is to pass a local port, immediately monitor the spawned
656	in the init function, monitor the original port. This two-way monitoring	596	port, and in the remote init function, immediately monitor the passed
657	ensures that both ports get cleaned up when there is a problem.	597	local port. This two-way monitoring ensures that both ports get cleaned up
		598	when there is a problem.
658		599
659	Example: spawn a chat server port on C<$othernode>.	600	Example: spawn a chat server port on C<$othernode>.
660		601
661	# this node, executed from within a port context:	602	# this node, executed from within a port context:
662	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	603	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
692	my $id = "$RUNIQ." . $ID++;	633	my $id = "$RUNIQ." . $ID++;
693		634
694	$_[0] =~ /::/	635	$_[0] =~ /::/
695	or Carp::croak "spawn init function must be a fully-qualified name, caught";	636	or Carp::croak "spawn init function must be a fully-qualified name, caught";
696		637
697	($NODE{$noderef} \|\| add_node $noderef)	638	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
698	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
699		639
700	"$noderef#$id"	640	"$noderef#$id"
701	}	641	}
702		642
703	=back	643	=item after $timeout, @msg
704		644
705	=head1 NODE MESSAGES	645	=item after $timeout, $callback
706		646
707	Nodes understand the following messages sent to them. Many of them take	647	Either sends the given message, or call the given callback, after the
708	arguments called C<@reply>, which will simply be used to compose a reply	648	specified number of seconds.
709	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
710	the remaining arguments are simply the message data.
711		649
712	While other messages exist, they are not public and subject to change.	650	This is simply a utility function that comes in handy at times - the
		651	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		652	so it may go away in the future.
713		653
714	=over 4
715
716	=cut	654	=cut
717		655
718	=item lookup => $name, @reply	656	sub after($@) {
		657	my ($timeout, @action) = @_;
719		658
720	Replies with the port ID of the specified well-known port, or C<undef>.	659	my $t; $t = AE::timer $timeout, 0, sub {
721		660	undef $t;
722	=item devnull => ...	661	ref $action[0]
723		662	? $action[0]()
724	Generic data sink/CPU heat conversion.	663	: snd @action;
725		664	};
726	=item relay => $port, @msg	665	}
727
728	Simply forwards the message to the given port.
729
730	=item eval => $string[ @reply]
731
732	Evaluates the given string. If C<@reply> is given, then a message of the
733	form C<@reply, $@, @evalres> is sent.
734
735	Example: crash another node.
736
737	snd $othernode, eval => "exit";
738
739	=item time => @reply
740
741	Replies the the current node time to C<@reply>.
742
743	Example: tell the current node to send the current time to C<$myport> in a
744	C<timereply> message.
745
746	snd $NODE, time => $myport, timereply => 1, 2;
747	# => snd $myport, timereply => 1, 2, <time>
748		666
749	=back	667	=back
750		668
751	=head1 AnyEvent::MP vs. Distributed Erlang	669	=head1 AnyEvent::MP vs. Distributed Erlang
752		670
…		…
762		680
763	Despite the similarities, there are also some important differences:	681	Despite the similarities, there are also some important differences:
764		682
765	=over 4	683	=over 4
766		684
767	=item * Node references contain the recipe on how to contact them.	685	=item * Node IDs are arbitrary strings in AEMP.
768		686
769	Erlang relies on special naming and DNS to work everywhere in the	687	Erlang relies on special naming and DNS to work everywhere in the same
770	same way. AEMP relies on each node knowing it's own address(es), with	688	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
771	convenience functionality.	689	configuraiton or DNS), but will otherwise discover other odes itself.
772		690
773	This means that AEMP requires a less tightly controlled environment at the	691	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
774	cost of longer node references and a slightly higher management overhead.	692	uses "local ports are like remote ports".
		693
		694	The failure modes for local ports are quite different (runtime errors
		695	only) then for remote ports - when a local port dies, you I<know> it dies,
		696	when a connection to another node dies, you know nothing about the other
		697	port.
		698
		699	Erlang pretends remote ports are as reliable as local ports, even when
		700	they are not.
		701
		702	AEMP encourages a "treat remote ports differently" philosophy, with local
		703	ports being the special case/exception, where transport errors cannot
		704	occur.
775		705
776	=item * Erlang uses processes and a mailbox, AEMP does not queue.	706	=item * Erlang uses processes and a mailbox, AEMP does not queue.
777		707
778	Erlang uses processes that selctively receive messages, and therefore	708	Erlang uses processes that selectively receive messages, and therefore
779	needs a queue. AEMP is event based, queuing messages would serve no useful	709	needs a queue. AEMP is event based, queuing messages would serve no
780	purpose.	710	useful purpose. For the same reason the pattern-matching abilities of
		711	AnyEvent::MP are more limited, as there is little need to be able to
		712	filter messages without dequeing them.
781		713
782	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	714	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
783		715
784	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	716	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
785		717
786	Sending messages in Erlang is synchronous and blocks the process. AEMP	718	Sending messages in Erlang is synchronous and blocks the process (and
787	sends are immediate, connection establishment is handled in the	719	so does not need a queue that can overflow). AEMP sends are immediate,
788	background.	720	connection establishment is handled in the background.
789		721
790	=item * Erlang can silently lose messages, AEMP cannot.	722	=item * Erlang suffers from silent message loss, AEMP does not.
791		723
792	Erlang makes few guarantees on messages delivery - messages can get lost	724	Erlang makes few guarantees on messages delivery - messages can get lost
793	without any of the processes realising it (i.e. you send messages a, b,	725	without any of the processes realising it (i.e. you send messages a, b,
794	and c, and the other side only receives messages a and c).	726	and c, and the other side only receives messages a and c).
795		727
796	AEMP guarantees correct ordering, and the guarantee that there are no	728	AEMP guarantees correct ordering, and the guarantee that after one message
797	holes in the message sequence.	729	is lost, all following ones sent to the same port are lost as well, until
798		730	monitoring raises an error, so there are no silent "holes" in the message
799	=item * In Erlang, processes can be declared dead and later be found to be	731	sequence.
800	alive.
801
802	In Erlang it can happen that a monitored process is declared dead and
803	linked processes get killed, but later it turns out that the process is
804	still alive - and can receive messages.
805
806	In AEMP, when port monitoring detects a port as dead, then that port will
807	eventually be killed - it cannot happen that a node detects a port as dead
808	and then later sends messages to it, finding it is still alive.
809		732
810	=item * Erlang can send messages to the wrong port, AEMP does not.	733	=item * Erlang can send messages to the wrong port, AEMP does not.
811		734
812	In Erlang it is quite possible that a node that restarts reuses a process	735	In Erlang it is quite likely that a node that restarts reuses a process ID
813	ID known to other nodes for a completely different process, causing	736	known to other nodes for a completely different process, causing messages
814	messages destined for that process to end up in an unrelated process.	737	destined for that process to end up in an unrelated process.
815		738
816	AEMP never reuses port IDs, so old messages or old port IDs floating	739	AEMP never reuses port IDs, so old messages or old port IDs floating
817	around in the network will not be sent to an unrelated port.	740	around in the network will not be sent to an unrelated port.
818		741
819	=item * Erlang uses unprotected connections, AEMP uses secure	742	=item * Erlang uses unprotected connections, AEMP uses secure
820	authentication and can use TLS.	743	authentication and can use TLS.
821		744
822	AEMP can use a proven protocol - SSL/TLS - to protect connections and	745	AEMP can use a proven protocol - TLS - to protect connections and
823	securely authenticate nodes.	746	securely authenticate nodes.
824		747
825	=item * The AEMP protocol is optimised for both text-based and binary	748	=item * The AEMP protocol is optimised for both text-based and binary
826	communications.	749	communications.
827		750
828	The AEMP protocol, unlike the Erlang protocol, supports both	751	The AEMP protocol, unlike the Erlang protocol, supports both programming
829	language-independent text-only protocols (good for debugging) and binary,	752	language independent text-only protocols (good for debugging) and binary,
830	language-specific serialisers (e.g. Storable).	753	language-specific serialisers (e.g. Storable). By default, unless TLS is
		754	used, the protocol is actually completely text-based.
831		755
832	It has also been carefully designed to be implementable in other languages	756	It has also been carefully designed to be implementable in other languages
833	with a minimum of work while gracefully degrading fucntionality to make the	757	with a minimum of work while gracefully degrading functionality to make the
834	protocol simple.	758	protocol simple.
835		759
836	=item * AEMP has more flexible monitoring options than Erlang.	760	=item * AEMP has more flexible monitoring options than Erlang.
837		761
838	In Erlang, you can chose to receive I<all> exit signals as messages	762	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
841	Erlang, as one can choose between automatic kill, exit message or callback	765	Erlang, as one can choose between automatic kill, exit message or callback
842	on a per-process basis.	766	on a per-process basis.
843		767
844	=item * Erlang tries to hide remote/local connections, AEMP does not.	768	=item * Erlang tries to hide remote/local connections, AEMP does not.
845		769
846	Monitoring in Erlang is not an indicator of process death/crashes,	770	Monitoring in Erlang is not an indicator of process death/crashes, in the
847	as linking is (except linking is unreliable in Erlang).	771	same way as linking is (except linking is unreliable in Erlang).
848		772
849	In AEMP, you don't "look up" registered port names or send to named ports	773	In AEMP, you don't "look up" registered port names or send to named ports
850	that might or might not be persistent. Instead, you normally spawn a port	774	that might or might not be persistent. Instead, you normally spawn a port
851	on the remote node. The init function monitors the you, and you monitor	775	on the remote node. The init function monitors you, and you monitor the
852	the remote port. Since both monitors are local to the node, they are much	776	remote port. Since both monitors are local to the node, they are much more
853	more reliable.	777	reliable (no need for C<spawn_link>).
854		778
855	This also saves round-trips and avoids sending messages to the wrong port	779	This also saves round-trips and avoids sending messages to the wrong port
856	(hard to do in Erlang).	780	(hard to do in Erlang).
857		781
858	=back	782	=back
859		783
860	=head1 RATIONALE	784	=head1 RATIONALE
861		785
862	=over 4	786	=over 4
863		787
864	=item Why strings for ports and noderefs, why not objects?	788	=item Why strings for port and node IDs, why not objects?
865		789
866	We considered "objects", but found that the actual number of methods	790	We considered "objects", but found that the actual number of methods
867	thatc an be called are very low. Since port IDs and noderefs travel over	791	that can be called are quite low. Since port and node IDs travel over
868	the network frequently, the serialising/deserialising would add lots of	792	the network frequently, the serialising/deserialising would add lots of
869	overhead, as well as having to keep a proxy object.	793	overhead, as well as having to keep a proxy object everywhere.
870		794
871	Strings can easily be printed, easily serialised etc. and need no special	795	Strings can easily be printed, easily serialised etc. and need no special
872	procedures to be "valid".	796	procedures to be "valid".
873		797
874	And a a miniport consists of a single closure stored in a global hash - it	798	And as a result, a miniport consists of a single closure stored in a
875	can't become much cheaper.	799	global hash - it can't become much cheaper.
876		800
877	=item Why favour JSON, why not real serialising format such as Storable?	801	=item Why favour JSON, why not a real serialising format such as Storable?
878		802
879	In fact, any AnyEvent::MP node will happily accept Storable as framing	803	In fact, any AnyEvent::MP node will happily accept Storable as framing
880	format, but currently there is no way to make a node use Storable by	804	format, but currently there is no way to make a node use Storable by
881	default.	805	default (although all nodes will accept it).
882		806
883	The default framing protocol is JSON because a) JSON::XS is many times	807	The default framing protocol is JSON because a) JSON::XS is many times
884	faster for small messages and b) most importantly, after years of	808	faster for small messages and b) most importantly, after years of
885	experience we found that object serialisation is causing more problems	809	experience we found that object serialisation is causing more problems
886	than it gains: Just like function calls, objects simply do not travel	810	than it solves: Just like function calls, objects simply do not travel
887	easily over the network, mostly because they will always be a copy, so you	811	easily over the network, mostly because they will always be a copy, so you
888	always have to re-think your design.	812	always have to re-think your design.
889		813
890	Keeping your messages simple, concentrating on data structures rather than	814	Keeping your messages simple, concentrating on data structures rather than
891	objects, will keep your messages clean, tidy and efficient.	815	objects, will keep your messages clean, tidy and efficient.
892		816
893	=back	817	=back
894		818
895	=head1 SEE ALSO	819	=head1 SEE ALSO
896		820
		821	L<AnyEvent::MP::Intro> - a gentle introduction.
		822
		823	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		824
		825	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		826	your applications.
		827
897	L<AnyEvent>.	828	L<AnyEvent>.
898		829
899	=head1 AUTHOR	830	=head1 AUTHOR
900		831
901	Marc Lehmann <schmorp@schmorp.de>	832	Marc Lehmann <schmorp@schmorp.de>

Diff Legend

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

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs. Revision 1.71 by root, Sun Aug 30 19:52:56 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs.
Revision 1.71 by root, Sun Aug 30 19:52:56 2009 UTC