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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.76 by root, Mon Aug 31 18:45:05 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
13	$SELF # receiving/own port id in rcv callbacks	12	$SELF # receiving/own port id in rcv callbacks
14		13
15	# initialise the node so it can send/receive messages	14	# initialise the node so it can send/receive messages
16	initialise_node; # -OR-	15	configure;
17	initialise_node "localhost:4040"; # -OR-
18	initialise_node "slave/", "localhost:4040"
19		16
20	# ports are message endpoints	17	# ports are message destinations
21		18
22	# sending messages	19	# sending messages
23	snd $port, type => data...;	20	snd $port, type => data...;
24	snd $port, @msg;	21	snd $port, @msg;
25	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
26		23
27	# creating/using miniports	24	# creating/using ports, the simple way
28	my $miniport = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
29		26
30	# creating/using full ports	27	# creating/using ports, tagged message matching
31	my $port = port;	28	my $port = port;
32	rcv $port, smartmatch => $cb->(@msg);
33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
34	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
35
36	# more, smarter, matches (_any_ is exported by this module)
37	rcv $port, [child_died => $pid] => sub { ...
38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
39		31
40	# create a port on another node	32	# create a port on another node
41	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
42		34
43	# monitoring	35	# monitoring
…		…
45	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
46	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
47		39
48	=head1 CURRENT STATUS	40	=head1 CURRENT STATUS
49		41
		42	bin/aemp - stable.
50	AnyEvent::MP - stable API, should work	43	AnyEvent::MP - stable API, should work.
51	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - epxlains most concepts.
52	AnyEvent::MP::Kernel - WIP
53	AnyEvent::MP::Transport - mostly stable	45	AnyEvent::MP::Kernel - mostly stable.
		46	AnyEvent::MP::Global - stable API, protocol not yet final.
54		47
55	stay tuned.	48	stay tuned.
56		49
57	=head1 DESCRIPTION	50	=head1 DESCRIPTION
58		51
59	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
60		53
61	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
62	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
63		56
64	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	57	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
65	manual page.	58	manual page and the examples under F<eg/>.
66
67	At the moment, this module family is severly broken and underdocumented,
68	so do not use. This was uploaded mainly to reserve the CPAN namespace -
69	stay tuned!
70		59
71	=head1 CONCEPTS	60	=head1 CONCEPTS
72		61
73	=over 4	62	=over 4
74		63
75	=item port	64	=item port
76		65
77	A port is something you can send messages to (with the C<snd> function).	66	A port is something you can send messages to (with the C<snd> function).
78		67
79	Some ports allow you to register C<rcv> handlers that can match specific	68	Ports allow you to register C<rcv> handlers that can match all or just
80	messages. All C<rcv> handlers will receive messages they match, messages	69	some messages. Messages send to ports will not be queued, regardless of
81	will not be queued.	70	anything was listening for them or not.
82		71
83	=item port id - C<noderef#portname>	72	=item port ID - C<nodeid#portname>
84		73
85	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	74	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
86	separator, and a port name (a printable string of unspecified format). An	75	separator, and a port name (a printable string of unspecified format).
87	exception is the the node port, whose ID is identical to its node
88	reference.
89		76
90	=item node	77	=item node
91		78
92	A node is a single process containing at least one port - the node	79	A node is a single process containing at least one port - the node port,
93	port. You can send messages to node ports to find existing ports or to	80	which enables nodes to manage each other remotely, and to create new
94	create new ports, among other things.	81	ports.
95		82
96	Nodes are either private (single-process only), slaves (connected to a	83	Nodes are either public (have one or more listening ports) or private
97	master node only) or public nodes (connectable from unrelated nodes).	84	(no listening ports). Private nodes cannot talk to other private nodes
		85	currently.
98		86
99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	87	=item node ID - C<[a-za-Z0-9_\-.:]+>
100		88
101	A node reference is a string that either simply identifies the node (for	89	A node ID is a string that uniquely identifies the node within a
102	private and slave nodes), or contains a recipe on how to reach a given	90	network. Depending on the configuration used, node IDs can look like a
103	node (for public nodes).	91	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		92	doesn't interpret node IDs in any way.
104		93
105	This recipe is simply a comma-separated list of C<address:port> pairs (for	94	=item binds - C<ip:port>
106	TCP/IP, other protocols might look different).
107		95
108	Node references come in two flavours: resolved (containing only numerical	96	Nodes can only talk to each other by creating some kind of connection to
109	addresses) or unresolved (where hostnames are used instead of addresses).	97	each other. To do this, nodes should listen on one or more local transport
		98	endpoints - binds. Currently, only standard C<ip:port> specifications can
		99	be used, which specify TCP ports to listen on.
110		100
111	Before using an unresolved node reference in a message you first have to	101	=item seeds - C<host:port>
112	resolve it.	102
		103	When a node starts, it knows nothing about the network. To teach the node
		104	about the network it first has to contact some other node within the
		105	network. This node is called a seed.
		106
		107	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		108	are expected to be long-running, and at least one of those should always
		109	be available. When nodes run out of connections (e.g. due to a network
		110	error), they try to re-establish connections to some seednodes again to
		111	join the network.
		112
		113	Apart from being sued for seeding, seednodes are not special in any way -
		114	every public node can be a seednode.
113		115
114	=back	116	=back
115		117
116	=head1 VARIABLES/FUNCTIONS	118	=head1 VARIABLES/FUNCTIONS
117		119
…		…
132	use base "Exporter";	134	use base "Exporter";
133		135
134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
135		137
136	our @EXPORT = qw(	138	our @EXPORT = qw(
137	NODE $NODE *SELF node_of _any_	139	NODE $NODE *SELF node_of after
138	resolve_node initialise_node	140	configure
139	snd rcv mon kil reg psub spawn	141	snd rcv mon mon_guard kil reg psub spawn
140	port	142	port
141	);	143	);
142		144
143	our $SELF;	145	our $SELF;
144		146
…		…
148	kil $SELF, die => $msg;	150	kil $SELF, die => $msg;
149	}	151	}
150		152
151	=item $thisnode = NODE / $NODE	153	=item $thisnode = NODE / $NODE
152		154
153	The C<NODE> function returns, and the C<$NODE> variable contains	155	The C<NODE> function returns, and the C<$NODE> variable contains, the node
154	the noderef of the local node. The value is initialised by a call	156	ID of the node running in the current process. This value is initialised by
155	to C<become_public> or C<become_slave>, after which all local port	157	a call to C<configure>.
156	identifiers become invalid.
157		158
158	=item $noderef = node_of $port	159	=item $nodeid = node_of $port
159		160
160	Extracts and returns the noderef from a portid or a noderef.	161	Extracts and returns the node ID from a port ID or a node ID.
161		162
162	=item initialise_node $noderef, $seednode, $seednode...	163	=item configure key => value...
163		164
164	=item initialise_node "slave/", $master, $master...
165
166	Before a node can talk to other nodes on the network it has to initialise	165	Before a node can talk to other nodes on the network (i.e. enter
167	itself - the minimum a node needs to know is it's own name, and optionally	166	"distributed mode") it has to configure itself - the minimum a node needs
168	it should know the noderefs of some other nodes in the network.	167	to know is its own name, and optionally it should know the addresses of
		168	some other nodes in the network to discover other nodes.
169		169
170	This function initialises a node - it must be called exactly once (or	170	This function configures a node - it must be called exactly once (or
171	never) before calling other AnyEvent::MP functions.	171	never) before calling other AnyEvent::MP functions.
172		172
173	All arguments (optionally except for the first) are noderefs, which can be
174	either resolved or unresolved.
175
176	The first argument will be looked up in the configuration database first
177	(if it is C<undef> then the current nodename will be used instead) to find
178	the relevant configuration profile (see L<aemp>). If none is found then
179	the default configuration is used. The configuration supplies additional
180	seed/master nodes and can override the actual noderef.
181
182	There are two types of networked nodes, public nodes and slave nodes:
183
184	=over 4	173	=over 4
185		174
186	=item public nodes	175	=item step 1, gathering configuration from profiles
187		176
188	For public nodes, C<$noderef> (supplied either directly to	177	The function first looks up a profile in the aemp configuration (see the
189	C<initialise_node> or indirectly via a profile or the nodename) must be a	178	L<aemp> commandline utility). The profile name can be specified via the
190	noderef (possibly unresolved, in which case it will be resolved).	179	named C<profile> parameter. If it is missing, then the nodename (F<uname
		180	-n>) will be used as profile name.
191		181
192	After resolving, the node will bind itself on all endpoints and try to	182	The profile data is then gathered as follows:
193	connect to all additional C<$seednodes> that are specified. Seednodes are
194	optional and can be used to quickly bootstrap the node into an existing
195	network.
196		183
197	=item slave nodes	184	First, all remaining key => value pairs (all of which are conviniently
		185	undocumented at the moment) will be interpreted as configuration
		186	data. Then they will be overwritten by any values specified in the global
		187	default configuration (see the F<aemp> utility), then the chain of
		188	profiles chosen by the profile name (and any C<parent> attributes).
198		189
199	When the C<$noderef> (either as given or overriden by the config file)	190	That means that the values specified in the profile have highest priority
200	is the special string C<slave/>, then the node will become a slave	191	and the values specified directly via C<configure> have lowest priority,
201	node. Slave nodes cannot be contacted from outside and will route most of	192	and can only be used to specify defaults.
202	their traffic to the master node that they attach to.
203		193
204	At least one additional noderef is required (either by specifying it	194	If the profile specifies a node ID, then this will become the node ID of
205	directly or because it is part of the configuration profile): The node	195	this process. If not, then the profile name will be used as node ID. The
206	will try to connect to all of them and will become a slave attached to the	196	special node ID of C<anon/> will be replaced by a random node ID.
207	first node it can successfully connect to.	197
		198	=item step 2, bind listener sockets
		199
		200	The next step is to look up the binds in the profile, followed by binding
		201	aemp protocol listeners on all binds specified (it is possible and valid
		202	to have no binds, meaning that the node cannot be contacted form the
		203	outside. This means the node cannot talk to other nodes that also have no
		204	binds, but it can still talk to all "normal" nodes).
		205
		206	If the profile does not specify a binds list, then a default of C<*> is
		207	used, meaning the node will bind on a dynamically-assigned port on every
		208	local IP address it finds.
		209
		210	=item step 3, connect to seed nodes
		211
		212	As the last step, the seeds list from the profile is passed to the
		213	L<AnyEvent::MP::Global> module, which will then use it to keep
		214	connectivity with at least one node at any point in time.
208		215
209	=back	216	=back
210		217
211	This function will block until all nodes have been resolved and, for slave	218	Example: become a distributed node using the locla node name as profile.
212	nodes, until it has successfully established a connection to a master	219	This should be the most common form of invocation for "daemon"-type nodes.
213	server.
214		220
215	Example: become a public node listening on the guessed noderef, or the one	221	configure
216	specified via C<aemp> for the current node. This should be the most common
217	form of invocation for "daemon"-type nodes.
218		222
219	initialise_node;	223	Example: become an anonymous node. This form is often used for commandline
		224	clients.
220		225
221	Example: become a slave node to any of the the seednodes specified via	226	configure nodeid => "anon/";
222	C<aemp>. This form is often used for commandline clients.
223		227
224	initialise_node "slave/";	228	Example: configure a node using a profile called seed, which si suitable
		229	for a seed node as it binds on all local addresses on a fixed port (4040,
		230	customary for aemp).
225		231
226	Example: become a slave node to any of the specified master servers. This	232	# use the aemp commandline utility
227	form is also often used for commandline clients.	233	# aemp profile seed nodeid anon/ binds '*:4040'
228		234
229	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";	235	# then use it
		236	configure profile => "seed";
230		237
231	Example: become a public node, and try to contact some well-known master	238	# or simply use aemp from the shell again:
232	servers to become part of the network.	239	# aemp run profile seed
233		240
234	initialise_node undef, "master1", "master2";	241	# or provide a nicer-to-remember nodeid
235		242	# aemp run profile seed nodeid "$(hostname)"
236	Example: become a public node listening on port C<4041>.
237
238	initialise_node 4041;
239
240	Example: become a public node, only visible on localhost port 4044.
241
242	initialise_node "localhost:4044";
243
244	=item $cv = resolve_node $noderef
245
246	Takes an unresolved node reference that may contain hostnames and
247	abbreviated IDs, resolves all of them and returns a resolved node
248	reference.
249
250	In addition to C<address:port> pairs allowed in resolved noderefs, the
251	following forms are supported:
252
253	=over 4
254
255	=item the empty string
256
257	An empty-string component gets resolved as if the default port (4040) was
258	specified.
259
260	=item naked port numbers (e.g. C<1234>)
261
262	These are resolved by prepending the local nodename and a colon, to be
263	further resolved.
264
265	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
266
267	These are resolved by using AnyEvent::DNS to resolve them, optionally
268	looking up SRV records for the C<aemp=4040> port, if no port was
269	specified.
270
271	=back
272		243
273	=item $SELF	244	=item $SELF
274		245
275	Contains the current port id while executing C<rcv> callbacks or C<psub>	246	Contains the current port id while executing C<rcv> callbacks or C<psub>
276	blocks.	247	blocks.
277		248
278	=item SELF, %SELF, @SELF...	249	=item *SELF, SELF, %SELF, @SELF...
279		250
280	Due to some quirks in how perl exports variables, it is impossible to	251	Due to some quirks in how perl exports variables, it is impossible to
281	just export C<$SELF>, all the symbols called C<SELF> are exported by this	252	just export C<$SELF>, all the symbols named C<SELF> are exported by this
282	module, but only C<$SELF> is currently used.	253	module, but only C<$SELF> is currently used.
283		254
284	=item snd $port, type => @data	255	=item snd $port, type => @data
285		256
286	=item snd $port, @msg	257	=item snd $port, @msg
287		258
288	Send the given message to the given port ID, which can identify either	259	Send the given message to the given port, which can identify either a
289	a local or a remote port, and can be either a string or soemthignt hat	260	local or a remote port, and must be a port ID.
290	stringifies a sa port ID (such as a port object :).
291		261
292	While the message can be about anything, it is highly recommended to use a	262	While the message can be almost anything, it is highly recommended to
293	string as first element (a portid, or some word that indicates a request	263	use a string as first element (a port ID, or some word that indicates a
294	type etc.).	264	request type etc.) and to consist if only simple perl values (scalars,
		265	arrays, hashes) - if you think you need to pass an object, think again.
295		266
296	The message data effectively becomes read-only after a call to this	267	The message data logically becomes read-only after a call to this
297	function: modifying any argument is not allowed and can cause many	268	function: modifying any argument (or values referenced by them) is
298	problems.	269	forbidden, as there can be considerable time between the call to C<snd>
		270	and the time the message is actually being serialised - in fact, it might
		271	never be copied as within the same process it is simply handed to the
		272	receiving port.
299		273
300	The type of data you can transfer depends on the transport protocol: when	274	The type of data you can transfer depends on the transport protocol: when
301	JSON is used, then only strings, numbers and arrays and hashes consisting	275	JSON is used, then only strings, numbers and arrays and hashes consisting
302	of those are allowed (no objects). When Storable is used, then anything	276	of those are allowed (no objects). When Storable is used, then anything
303	that Storable can serialise and deserialise is allowed, and for the local	277	that Storable can serialise and deserialise is allowed, and for the local
304	node, anything can be passed.	278	node, anything can be passed. Best rely only on the common denominator of
		279	these.
305		280
306	=item $local_port = port	281	=item $local_port = port
307		282
308	Create a new local port object that can be used either as a pattern	283	Create a new local port object and returns its port ID. Initially it has
309	matching port ("full port") or a single-callback port ("miniport"),	284	no callbacks set and will throw an error when it receives messages.
310	depending on how C<rcv> callbacks are bound to the object.
311		285
312	=item $port = port { my @msg = @_; $finished }	286	=item $local_port = port { my @msg = @_ }
313		287
314	Creates a "miniport", that is, a very lightweight port without any pattern	288	Creates a new local port, and returns its ID. Semantically the same as
315	matching behind it, and returns its ID. Semantically the same as creating
316	a port and calling C<rcv $port, $callback> on it.	289	creating a port and calling C<rcv $port, $callback> on it.
317		290
318	The block will be called for every message received on the port. When the	291	The block will be called for every message received on the port, with the
319	callback returns a true value its job is considered "done" and the port	292	global variable C<$SELF> set to the port ID. Runtime errors will cause the
320	will be destroyed. Otherwise it will stay alive.	293	port to be C<kil>ed. The message will be passed as-is, no extra argument
		294	(i.e. no port ID) will be passed to the callback.
321		295
322	The message will be passed as-is, no extra argument (i.e. no port id) will	296	If you want to stop/destroy the port, simply C<kil> it:
323	be passed to the callback.
324		297
325	If you need the local port id in the callback, this works nicely:	298	my $port = port {
326		299	my @msg = @_;
327	my $port; $port = port {	300	...
328	snd $otherport, reply => $port;	301	kil $SELF;
329	};	302	};
330		303
331	=cut	304	=cut
332		305
333	sub rcv($@);	306	sub rcv($@);
		307
		308	sub _kilme {
		309	die "received message on port without callback";
		310	}
334		311
335	sub port(;&) {	312	sub port(;&) {
336	my $id = "$UNIQ." . $ID++;	313	my $id = "$UNIQ." . $ID++;
337	my $port = "$NODE#$id";	314	my $port = "$NODE#$id";
338		315
339	if (@_) {	316	rcv $port, shift \|\| \&_kilme;
340	rcv $port, shift;
341	} else {
342	$PORT{$id} = sub { }; # nop
343	}
344		317
345	$port	318	$port
346	}	319	}
347		320
348	=item reg $port, $name
349
350	=item reg $name
351
352	Registers the given port (or C<$SELF><<< if missing) under the name
353	C<$name>. If the name already exists it is replaced.
354
355	A port can only be registered under one well known name.
356
357	A port automatically becomes unregistered when it is killed.
358
359	=cut
360
361	sub reg(@) {
362	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
363
364	$REG{$_[0]} = $port;
365	}
366
367	=item rcv $port, $callback->(@msg)	321	=item rcv $local_port, $callback->(@msg)
368		322
369	Replaces the callback on the specified miniport (after converting it to	323	Replaces the default callback on the specified port. There is no way to
370	one if required).	324	remove the default callback: use C<sub { }> to disable it, or better
371		325	C<kil> the port when it is no longer needed.
372	=item rcv $port, tagstring => $callback->(@msg), ...
373
374	=item rcv $port, $smartmatch => $callback->(@msg), ...
375
376	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
377
378	Register callbacks to be called on matching messages on the given full
379	port (after converting it to one if required) and return the port.
380
381	The callback has to return a true value when its work is done, after
382	which is will be removed, or a false value in which case it will stay
383	registered.
384		326
385	The global C<$SELF> (exported by this module) contains C<$port> while	327	The global C<$SELF> (exported by this module) contains C<$port> while
386	executing the callback.	328	executing the callback. Runtime errors during callback execution will
		329	result in the port being C<kil>ed.
387		330
388	Runtime errors during callback execution will result in the port being	331	The default callback received all messages not matched by a more specific
389	C<kil>ed.	332	C<tag> match.
390		333
391	If the match is an array reference, then it will be matched against the	334	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
392	first elements of the message, otherwise only the first element is being
393	matched.
394		335
395	Any element in the match that is specified as C<_any_> (a function	336	Register (or replace) callbacks to be called on messages starting with the
396	exported by this module) matches any single element of the message.	337	given tag on the given port (and return the port), or unregister it (when
		338	C<$callback> is C<$undef> or missing). There can only be one callback
		339	registered for each tag.
397		340
398	While not required, it is highly recommended that the first matching	341	The original message will be passed to the callback, after the first
399	element is a string identifying the message. The one-string-only match is	342	element (the tag) has been removed. The callback will use the same
400	also the most efficient match (by far).	343	environment as the default callback (see above).
401		344
402	Example: create a port and bind receivers on it in one go.	345	Example: create a port and bind receivers on it in one go.
403		346
404	my $port = rcv port,	347	my $port = rcv port,
405	msg1 => sub { ...; 0 },	348	msg1 => sub { ... },
406	msg2 => sub { ...; 0 },	349	msg2 => sub { ... },
407	;	350	;
408		351
409	Example: create a port, bind receivers and send it in a message elsewhere	352	Example: create a port, bind receivers and send it in a message elsewhere
410	in one go:	353	in one go:
411		354
412	snd $otherport, reply =>	355	snd $otherport, reply =>
413	rcv port,	356	rcv port,
414	msg1 => sub { ...; 0 },	357	msg1 => sub { ... },
415	...	358	...
416	;	359	;
417		360
		361	Example: temporarily register a rcv callback for a tag matching some port
		362	(e.g. for a rpc reply) and unregister it after a message was received.
		363
		364	rcv $port, $otherport => sub {
		365	my @reply = @_;
		366
		367	rcv $SELF, $otherport;
		368	};
		369
418	=cut	370	=cut
419		371
420	sub rcv($@) {	372	sub rcv($@) {
421	my $port = shift;	373	my $port = shift;
422	my ($noderef, $portid) = split /#/, $port, 2;	374	my ($nodeid, $portid) = split /#/, $port, 2;
423		375
424	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	376	$NODE{$nodeid} == $NODE{""}
425	or Carp::croak "$port: rcv can only be called on local ports, caught";	377	or Carp::croak "$port: rcv can only be called on local ports, caught";
426		378
427	if (@_ == 1) {	379	while (@_) {
		380	if (ref $_[0]) {
		381	if (my $self = $PORT_DATA{$portid}) {
		382	"AnyEvent::MP::Port" eq ref $self
		383	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		384
		385	$self->[2] = shift;
		386	} else {
428	my $cb = shift;	387	my $cb = shift;
429	delete $PORT_DATA{$portid};
430	$PORT{$portid} = sub {	388	$PORT{$portid} = sub {
431	local $SELF = $port;	389	local $SELF = $port;
432	eval {	390	eval { &$cb }; _self_die if $@;
433	&$cb	391	};
434	and kil $port;
435	};	392	}
436	_self_die if $@;	393	} elsif (defined $_[0]) {
437	};
438	} else {
439	my $self = $PORT_DATA{$portid} \|\|= do {	394	my $self = $PORT_DATA{$portid} \|\|= do {
440	my $self = bless {	395	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
441	id => $port,
442	}, "AnyEvent::MP::Port";
443		396
444	$PORT{$portid} = sub {	397	$PORT{$portid} = sub {
445	local $SELF = $port;	398	local $SELF = $port;
446		399
447	eval {
448	for (@{ $self->{rc0}{$_[0]} }) {	400	if (my $cb = $self->[1]{$_[0]}) {
449	$_ && &{$_->[0]}	401	shift;
450	&& undef $_;	402	eval { &$cb }; _self_die if $@;
451	}	403	} else {
452
453	for (@{ $self->{rcv}{$_[0]} }) {
454	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
455	&& &{$_->[0]}	404	&{ $self->[0] };
456	&& undef $_;
457	}
458
459	for (@{ $self->{any} }) {
460	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
461	&& &{$_->[0]}
462	&& undef $_;
463	}	405	}
464	};	406	};
465	_self_die if $@;	407
		408	$self
466	};	409	};
467		410
468	$self
469	};
470
471	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
472	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	412	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
473		413
474	while (@_) {
475	my ($match, $cb) = splice @_, 0, 2;	414	my ($tag, $cb) = splice @_, 0, 2;
476		415
477	if (!ref $match) {	416	if (defined $cb) {
478	push @{ $self->{rc0}{$match} }, [$cb];	417	$self->[1]{$tag} = $cb;
479	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
480	my ($type, @match) = @$match;
481	@match
482	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
483	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
484	} else {	418	} else {
485	push @{ $self->{any} }, [$cb, $match];	419	delete $self->[1]{$tag};
486	}	420	}
487	}	421	}
488	}	422	}
489		423
490	$port	424	$port
…		…
526	$res	460	$res
527	}	461	}
528	}	462	}
529	}	463	}
530		464
531	=item $guard = mon $port, $cb->(@reason)	465	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
532		466
533	=item $guard = mon $port, $rcvport	467	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
534		468
535	=item $guard = mon $port	469	=item $guard = mon $port # kill $SELF when $port dies
536		470
537	=item $guard = mon $port, $rcvport, @msg	471	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
538		472
539	Monitor the given port and do something when the port is killed or	473	Monitor the given port and do something when the port is killed or
540	messages to it were lost, and optionally return a guard that can be used	474	messages to it were lost, and optionally return a guard that can be used
541	to stop monitoring again.	475	to stop monitoring again.
542		476
543	C<mon> effectively guarantees that, in the absence of hardware failures,	477	C<mon> effectively guarantees that, in the absence of hardware failures,
544	that after starting the monitor, either all messages sent to the port	478	after starting the monitor, either all messages sent to the port will
545	will arrive, or the monitoring action will be invoked after possible	479	arrive, or the monitoring action will be invoked after possible message
546	message loss has been detected. No messages will be lost "in between"	480	loss has been detected. No messages will be lost "in between" (after
547	(after the first lost message no further messages will be received by the	481	the first lost message no further messages will be received by the
548	port). After the monitoring action was invoked, further messages might get	482	port). After the monitoring action was invoked, further messages might get
549	delivered again.	483	delivered again.
		484
		485	Note that monitoring-actions are one-shot: once messages are lost (and a
		486	monitoring alert was raised), they are removed and will not trigger again.
550		487
551	In the first form (callback), the callback is simply called with any	488	In the first form (callback), the callback is simply called with any
552	number of C<@reason> elements (no @reason means that the port was deleted	489	number of C<@reason> elements (no @reason means that the port was deleted
553	"normally"). Note also that I<< the callback B<must> never die >>, so use	490	"normally"). Note also that I<< the callback B<must> never die >>, so use
554	C<eval> if unsure.	491	C<eval> if unsure.
…		…
584	mon $port, $self => "restart";	521	mon $port, $self => "restart";
585		522
586	=cut	523	=cut
587		524
588	sub mon {	525	sub mon {
589	my ($noderef, $port) = split /#/, shift, 2;	526	my ($nodeid, $port) = split /#/, shift, 2;
590		527
591	my $node = $NODE{$noderef} \|\| add_node $noderef;	528	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
592		529
593	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	530	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
594		531
595	unless (ref $cb) {	532	unless (ref $cb) {
596	if (@_) {	533	if (@_) {
…		…
616	is killed, the references will be freed.	553	is killed, the references will be freed.
617		554
618	Optionally returns a guard that will stop the monitoring.	555	Optionally returns a guard that will stop the monitoring.
619		556
620	This function is useful when you create e.g. timers or other watchers and	557	This function is useful when you create e.g. timers or other watchers and
621	want to free them when the port gets killed:	558	want to free them when the port gets killed (note the use of C<psub>):
622		559
623	$port->rcv (start => sub {	560	$port->rcv (start => sub {
624	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	561	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
625	undef $timer if 0.9 < rand;	562	undef $timer if 0.9 < rand;
626	});	563	});
627	});	564	});
628		565
629	=cut	566	=cut
…		…
638		575
639	=item kil $port[, @reason]	576	=item kil $port[, @reason]
640		577
641	Kill the specified port with the given C<@reason>.	578	Kill the specified port with the given C<@reason>.
642		579
643	If no C<@reason> is specified, then the port is killed "normally" (linked	580	If no C<@reason> is specified, then the port is killed "normally" (ports
644	ports will not be kileld, or even notified).	581	monitoring other ports will not necessarily die because a port dies
		582	"normally").
645		583
646	Otherwise, linked ports get killed with the same reason (second form of	584	Otherwise, linked ports get killed with the same reason (second form of
647	C<mon>, see below).	585	C<mon>, see above).
648		586
649	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	587	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
650	will be reported as reason C<< die => $@ >>.	588	will be reported as reason C<< die => $@ >>.
651		589
652	Transport/communication errors are reported as C<< transport_error =>	590	Transport/communication errors are reported as C<< transport_error =>
…		…
657	=item $port = spawn $node, $initfunc[, @initdata]	595	=item $port = spawn $node, $initfunc[, @initdata]
658		596
659	Creates a port on the node C<$node> (which can also be a port ID, in which	597	Creates a port on the node C<$node> (which can also be a port ID, in which
660	case it's the node where that port resides).	598	case it's the node where that port resides).
661		599
662	The port ID of the newly created port is return immediately, and it is	600	The port ID of the newly created port is returned immediately, and it is
663	permissible to immediately start sending messages or monitor the port.	601	possible to immediately start sending messages or to monitor the port.
664		602
665	After the port has been created, the init function is	603	After the port has been created, the init function is called on the remote
666	called. This function must be a fully-qualified function name	604	node, in the same context as a C<rcv> callback. This function must be a
667	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	605	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
668	program, use C<::name>.	606	specify a function in the main program, use C<::name>.
669		607
670	If the function doesn't exist, then the node tries to C<require>	608	If the function doesn't exist, then the node tries to C<require>
671	the package, then the package above the package and so on (e.g.	609	the package, then the package above the package and so on (e.g.
672	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	610	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
673	exists or it runs out of package names.	611	exists or it runs out of package names.
674		612
675	The init function is then called with the newly-created port as context	613	The init function is then called with the newly-created port as context
676	object (C<$SELF>) and the C<@initdata> values as arguments.	614	object (C<$SELF>) and the C<@initdata> values as arguments.
677		615
678	A common idiom is to pass your own port, monitor the spawned port, and	616	A common idiom is to pass a local port, immediately monitor the spawned
679	in the init function, monitor the original port. This two-way monitoring	617	port, and in the remote init function, immediately monitor the passed
680	ensures that both ports get cleaned up when there is a problem.	618	local port. This two-way monitoring ensures that both ports get cleaned up
		619	when there is a problem.
681		620
682	Example: spawn a chat server port on C<$othernode>.	621	Example: spawn a chat server port on C<$othernode>.
683		622
684	# this node, executed from within a port context:	623	# this node, executed from within a port context:
685	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	624	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
708	};	647	};
709	_self_die if $@;	648	_self_die if $@;
710	}	649	}
711		650
712	sub spawn(@) {	651	sub spawn(@) {
713	my ($noderef, undef) = split /#/, shift, 2;	652	my ($nodeid, undef) = split /#/, shift, 2;
714		653
715	my $id = "$RUNIQ." . $ID++;	654	my $id = "$RUNIQ." . $ID++;
716		655
717	$_[0] =~ /::/	656	$_[0] =~ /::/
718	or Carp::croak "spawn init function must be a fully-qualified name, caught";	657	or Carp::croak "spawn init function must be a fully-qualified name, caught";
719		658
720	($NODE{$noderef} \|\| add_node $noderef)	659	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
721	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
722		660
723	"$noderef#$id"	661	"$nodeid#$id"
724	}	662	}
725		663
726	=back	664	=item after $timeout, @msg
727		665
728	=head1 NODE MESSAGES	666	=item after $timeout, $callback
729		667
730	Nodes understand the following messages sent to them. Many of them take	668	Either sends the given message, or call the given callback, after the
731	arguments called C<@reply>, which will simply be used to compose a reply	669	specified number of seconds.
732	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
733	the remaining arguments are simply the message data.
734		670
735	While other messages exist, they are not public and subject to change.	671	This is simply a utility function that comes in handy at times - the
		672	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		673	so it may go away in the future.
736		674
737	=over 4
738
739	=cut	675	=cut
740		676
741	=item lookup => $name, @reply	677	sub after($@) {
		678	my ($timeout, @action) = @_;
742		679
743	Replies with the port ID of the specified well-known port, or C<undef>.	680	my $t; $t = AE::timer $timeout, 0, sub {
744		681	undef $t;
745	=item devnull => ...	682	ref $action[0]
746		683	? $action[0]()
747	Generic data sink/CPU heat conversion.	684	: snd @action;
748		685	};
749	=item relay => $port, @msg	686	}
750
751	Simply forwards the message to the given port.
752
753	=item eval => $string[ @reply]
754
755	Evaluates the given string. If C<@reply> is given, then a message of the
756	form C<@reply, $@, @evalres> is sent.
757
758	Example: crash another node.
759
760	snd $othernode, eval => "exit";
761
762	=item time => @reply
763
764	Replies the the current node time to C<@reply>.
765
766	Example: tell the current node to send the current time to C<$myport> in a
767	C<timereply> message.
768
769	snd $NODE, time => $myport, timereply => 1, 2;
770	# => snd $myport, timereply => 1, 2, <time>
771		687
772	=back	688	=back
773		689
774	=head1 AnyEvent::MP vs. Distributed Erlang	690	=head1 AnyEvent::MP vs. Distributed Erlang
775		691
…		…
785		701
786	Despite the similarities, there are also some important differences:	702	Despite the similarities, there are also some important differences:
787		703
788	=over 4	704	=over 4
789		705
790	=item * Node references contain the recipe on how to contact them.	706	=item * Node IDs are arbitrary strings in AEMP.
791		707
792	Erlang relies on special naming and DNS to work everywhere in the	708	Erlang relies on special naming and DNS to work everywhere in the same
793	same way. AEMP relies on each node knowing it's own address(es), with	709	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
794	convenience functionality.	710	configuraiton or DNS), but will otherwise discover other odes itself.
795		711
796	This means that AEMP requires a less tightly controlled environment at the	712	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
797	cost of longer node references and a slightly higher management overhead.	713	uses "local ports are like remote ports".
		714
		715	The failure modes for local ports are quite different (runtime errors
		716	only) then for remote ports - when a local port dies, you I<know> it dies,
		717	when a connection to another node dies, you know nothing about the other
		718	port.
		719
		720	Erlang pretends remote ports are as reliable as local ports, even when
		721	they are not.
		722
		723	AEMP encourages a "treat remote ports differently" philosophy, with local
		724	ports being the special case/exception, where transport errors cannot
		725	occur.
798		726
799	=item * Erlang uses processes and a mailbox, AEMP does not queue.	727	=item * Erlang uses processes and a mailbox, AEMP does not queue.
800		728
801	Erlang uses processes that selctively receive messages, and therefore	729	Erlang uses processes that selectively receive messages, and therefore
802	needs a queue. AEMP is event based, queuing messages would serve no useful	730	needs a queue. AEMP is event based, queuing messages would serve no
803	purpose.	731	useful purpose. For the same reason the pattern-matching abilities of
		732	AnyEvent::MP are more limited, as there is little need to be able to
		733	filter messages without dequeing them.
804		734
805	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	735	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
806		736
807	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	737	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
808		738
809	Sending messages in Erlang is synchronous and blocks the process. AEMP	739	Sending messages in Erlang is synchronous and blocks the process (and
810	sends are immediate, connection establishment is handled in the	740	so does not need a queue that can overflow). AEMP sends are immediate,
811	background.	741	connection establishment is handled in the background.
812		742
813	=item * Erlang can silently lose messages, AEMP cannot.	743	=item * Erlang suffers from silent message loss, AEMP does not.
814		744
815	Erlang makes few guarantees on messages delivery - messages can get lost	745	Erlang makes few guarantees on messages delivery - messages can get lost
816	without any of the processes realising it (i.e. you send messages a, b,	746	without any of the processes realising it (i.e. you send messages a, b,
817	and c, and the other side only receives messages a and c).	747	and c, and the other side only receives messages a and c).
818		748
819	AEMP guarantees correct ordering, and the guarantee that there are no	749	AEMP guarantees correct ordering, and the guarantee that after one message
820	holes in the message sequence.	750	is lost, all following ones sent to the same port are lost as well, until
821		751	monitoring raises an error, so there are no silent "holes" in the message
822	=item * In Erlang, processes can be declared dead and later be found to be	752	sequence.
823	alive.
824
825	In Erlang it can happen that a monitored process is declared dead and
826	linked processes get killed, but later it turns out that the process is
827	still alive - and can receive messages.
828
829	In AEMP, when port monitoring detects a port as dead, then that port will
830	eventually be killed - it cannot happen that a node detects a port as dead
831	and then later sends messages to it, finding it is still alive.
832		753
833	=item * Erlang can send messages to the wrong port, AEMP does not.	754	=item * Erlang can send messages to the wrong port, AEMP does not.
834		755
835	In Erlang it is quite possible that a node that restarts reuses a process	756	In Erlang it is quite likely that a node that restarts reuses a process ID
836	ID known to other nodes for a completely different process, causing	757	known to other nodes for a completely different process, causing messages
837	messages destined for that process to end up in an unrelated process.	758	destined for that process to end up in an unrelated process.
838		759
839	AEMP never reuses port IDs, so old messages or old port IDs floating	760	AEMP never reuses port IDs, so old messages or old port IDs floating
840	around in the network will not be sent to an unrelated port.	761	around in the network will not be sent to an unrelated port.
841		762
842	=item * Erlang uses unprotected connections, AEMP uses secure	763	=item * Erlang uses unprotected connections, AEMP uses secure
843	authentication and can use TLS.	764	authentication and can use TLS.
844		765
845	AEMP can use a proven protocol - SSL/TLS - to protect connections and	766	AEMP can use a proven protocol - TLS - to protect connections and
846	securely authenticate nodes.	767	securely authenticate nodes.
847		768
848	=item * The AEMP protocol is optimised for both text-based and binary	769	=item * The AEMP protocol is optimised for both text-based and binary
849	communications.	770	communications.
850		771
851	The AEMP protocol, unlike the Erlang protocol, supports both	772	The AEMP protocol, unlike the Erlang protocol, supports both programming
852	language-independent text-only protocols (good for debugging) and binary,	773	language independent text-only protocols (good for debugging) and binary,
853	language-specific serialisers (e.g. Storable).	774	language-specific serialisers (e.g. Storable). By default, unless TLS is
		775	used, the protocol is actually completely text-based.
854		776
855	It has also been carefully designed to be implementable in other languages	777	It has also been carefully designed to be implementable in other languages
856	with a minimum of work while gracefully degrading fucntionality to make the	778	with a minimum of work while gracefully degrading functionality to make the
857	protocol simple.	779	protocol simple.
858		780
859	=item * AEMP has more flexible monitoring options than Erlang.	781	=item * AEMP has more flexible monitoring options than Erlang.
860		782
861	In Erlang, you can chose to receive I<all> exit signals as messages	783	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
864	Erlang, as one can choose between automatic kill, exit message or callback	786	Erlang, as one can choose between automatic kill, exit message or callback
865	on a per-process basis.	787	on a per-process basis.
866		788
867	=item * Erlang tries to hide remote/local connections, AEMP does not.	789	=item * Erlang tries to hide remote/local connections, AEMP does not.
868		790
869	Monitoring in Erlang is not an indicator of process death/crashes,	791	Monitoring in Erlang is not an indicator of process death/crashes, in the
870	as linking is (except linking is unreliable in Erlang).	792	same way as linking is (except linking is unreliable in Erlang).
871		793
872	In AEMP, you don't "look up" registered port names or send to named ports	794	In AEMP, you don't "look up" registered port names or send to named ports
873	that might or might not be persistent. Instead, you normally spawn a port	795	that might or might not be persistent. Instead, you normally spawn a port
874	on the remote node. The init function monitors the you, and you monitor	796	on the remote node. The init function monitors you, and you monitor the
875	the remote port. Since both monitors are local to the node, they are much	797	remote port. Since both monitors are local to the node, they are much more
876	more reliable.	798	reliable (no need for C<spawn_link>).
877		799
878	This also saves round-trips and avoids sending messages to the wrong port	800	This also saves round-trips and avoids sending messages to the wrong port
879	(hard to do in Erlang).	801	(hard to do in Erlang).
880		802
881	=back	803	=back
882		804
883	=head1 RATIONALE	805	=head1 RATIONALE
884		806
885	=over 4	807	=over 4
886		808
887	=item Why strings for ports and noderefs, why not objects?	809	=item Why strings for port and node IDs, why not objects?
888		810
889	We considered "objects", but found that the actual number of methods	811	We considered "objects", but found that the actual number of methods
890	thatc an be called are very low. Since port IDs and noderefs travel over	812	that can be called are quite low. Since port and node IDs travel over
891	the network frequently, the serialising/deserialising would add lots of	813	the network frequently, the serialising/deserialising would add lots of
892	overhead, as well as having to keep a proxy object.	814	overhead, as well as having to keep a proxy object everywhere.
893		815
894	Strings can easily be printed, easily serialised etc. and need no special	816	Strings can easily be printed, easily serialised etc. and need no special
895	procedures to be "valid".	817	procedures to be "valid".
896		818
897	And a a miniport consists of a single closure stored in a global hash - it	819	And as a result, a miniport consists of a single closure stored in a
898	can't become much cheaper.	820	global hash - it can't become much cheaper.
899		821
900	=item Why favour JSON, why not real serialising format such as Storable?	822	=item Why favour JSON, why not a real serialising format such as Storable?
901		823
902	In fact, any AnyEvent::MP node will happily accept Storable as framing	824	In fact, any AnyEvent::MP node will happily accept Storable as framing
903	format, but currently there is no way to make a node use Storable by	825	format, but currently there is no way to make a node use Storable by
904	default.	826	default (although all nodes will accept it).
905		827
906	The default framing protocol is JSON because a) JSON::XS is many times	828	The default framing protocol is JSON because a) JSON::XS is many times
907	faster for small messages and b) most importantly, after years of	829	faster for small messages and b) most importantly, after years of
908	experience we found that object serialisation is causing more problems	830	experience we found that object serialisation is causing more problems
909	than it gains: Just like function calls, objects simply do not travel	831	than it solves: Just like function calls, objects simply do not travel
910	easily over the network, mostly because they will always be a copy, so you	832	easily over the network, mostly because they will always be a copy, so you
911	always have to re-think your design.	833	always have to re-think your design.
912		834
913	Keeping your messages simple, concentrating on data structures rather than	835	Keeping your messages simple, concentrating on data structures rather than
914	objects, will keep your messages clean, tidy and efficient.	836	objects, will keep your messages clean, tidy and efficient.
915		837
916	=back	838	=back
917		839
918	=head1 SEE ALSO	840	=head1 SEE ALSO
919		841
		842	L<AnyEvent::MP::Intro> - a gentle introduction.
		843
		844	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		845
		846	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		847	your applications.
		848
920	L<AnyEvent>.	849	L<AnyEvent>.
921		850
922	=head1 AUTHOR	851	=head1 AUTHOR
923		852
924	Marc Lehmann <schmorp@schmorp.de>	853	Marc Lehmann <schmorp@schmorp.de>

Diff Legend

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

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs. Revision 1.76 by root, Mon Aug 31 18:45:05 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC vs.
Revision 1.76 by root, Mon Aug 31 18:45:05 2009 UTC