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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.44 by root, Wed Aug 12 21:39:58 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
		14	# initialise the node so it can send/receive messages
		15	configure;
		16
15	# ports are message endpoints	17	# ports are message destinations
16		18
17	# sending messages	19	# sending messages
18	snd $port, type => data...;	20	snd $port, type => data...;
19	snd $port, @msg;	21	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
21		23
22	# miniports	24	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
24		26
25	# full ports	27	# creating/using ports, tagged message matching
26	my $port = port;	28	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
30		31
31	# remote ports	32	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	33	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		34
38	# monitoring	35	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	36	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
42		39
		40	=head1 CURRENT STATUS
		41
		42	bin/aemp - stable.
		43	AnyEvent::MP - stable API, should work.
		44	AnyEvent::MP::Intro - epxlains most concepts.
		45	AnyEvent::MP::Kernel - mostly stable.
		46	AnyEvent::MP::Global - stable API, protocol not yet final.
		47
		48	stay tuned.
		49
43	=head1 DESCRIPTION	50	=head1 DESCRIPTION
44		51
45	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
46		53
47	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
48	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
49		56
50	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>
51	manual page.	58	manual page and the examples under F<eg/>.
52
53	At the moment, this module family is severly broken and underdocumented,
54	so do not use. This was uploaded mainly to reserve the CPAN namespace -
55	stay tuned! The basic API should be finished, however.
56		59
57	=head1 CONCEPTS	60	=head1 CONCEPTS
58		61
59	=over 4	62	=over 4
60		63
61	=item port	64	=item port
62		65
63	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).
64		67
65	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
66	messages. All C<rcv> handlers will receive messages they match, messages	69	some messages. Messages send to ports will not be queued, regardless of
67	will not be queued.	70	anything was listening for them or not.
68		71
69	=item port id - C<noderef#portname>	72	=item port ID - C<nodeid#portname>
70		73
71	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
72	separator, and a port name (a printable string of unspecified format). An	75	separator, and a port name (a printable string of unspecified format).
73	exception is the the node port, whose ID is identical to its node
74	reference.
75		76
76	=item node	77	=item node
77		78
78	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,
79	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
80	create new ports, among other things.	81	ports.
81		82
82	Nodes are either private (single-process only), slaves (connected to a	83	Nodes are either public (have one or more listening ports) or private
83	master node only) or public nodes (connectable from unrelated nodes).	84	(no listening ports). Private nodes cannot talk to other private nodes
		85	currently.
84		86
85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	87	=item node ID - C<[a-za-Z0-9_\-.:]+>
86		88
87	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
88	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
89	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.
90		93
91	This recipe is simply a comma-separated list of C<address:port> pairs (for	94	=item binds - C<ip:port>
92	TCP/IP, other protocols might look different).
93		95
94	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
95	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.
96		100
97	Before using an unresolved node reference in a message you first have to	101	=item seeds - C<host:port>
98	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.
99		115
100	=back	116	=back
101		117
102	=head1 VARIABLES/FUNCTIONS	118	=head1 VARIABLES/FUNCTIONS
103		119
…		…
118	use base "Exporter";	134	use base "Exporter";
119		135
120	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
121		137
122	our @EXPORT = qw(	138	our @EXPORT = qw(
123	NODE $NODE *SELF node_of _any_	139	NODE $NODE *SELF node_of after
124	resolve_node initialise_node	140	configure
125	snd rcv mon kil reg psub spawn	141	snd rcv mon mon_guard kil reg psub spawn
126	port	142	port
127	);	143	);
128		144
129	our $SELF;	145	our $SELF;
130		146
…		…
134	kil $SELF, die => $msg;	150	kil $SELF, die => $msg;
135	}	151	}
136		152
137	=item $thisnode = NODE / $NODE	153	=item $thisnode = NODE / $NODE
138		154
139	The C<NODE> function returns, and the C<$NODE> variable contains	155	The C<NODE> function returns, and the C<$NODE> variable contains, the node
140	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
141	to C<become_public> or C<become_slave>, after which all local port	157	a call to C<configure>.
142	identifiers become invalid.
143		158
144	=item $noderef = node_of $port	159	=item $nodeid = node_of $port
145		160
146	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.
147		162
148	=item initialise_node $noderef, $seednode, $seednode...	163	=item configure key => value...
149		164
150	=item initialise_node "slave/", $master, $master...
151
152	Before a node can talk to other nodes on the network it has to initialise	165	Before a node can talk to other nodes on the network (i.e. enter
153	itself - the minimum a node needs to know is it's own name, and optionally	166	"distributed mode") it has to configure itself - the minimum a node needs
154	it should know the noderefs of some other nodes in the network.	167	to know is its own name, and optionally it should know the addresses of
		168	some other nodes in the network to discover other nodes.
155		169
156	This function initialises a node - it must be called exactly once (or	170	This function configures a node - it must be called exactly once (or
157	never) before calling other AnyEvent::MP functions.	171	never) before calling other AnyEvent::MP functions.
158		172
159	All arguments are noderefs, which can be either resolved or unresolved.
160
161	There are two types of networked nodes, public nodes and slave nodes:
162
163	=over 4	173	=over 4
164		174
165	=item public nodes	175	=item step 1, gathering configuration from profiles
166		176
167	For public nodes, C<$noderef> must either be a (possibly unresolved)	177	The function first looks up a profile in the aemp configuration (see the
168	noderef, in which case it will be resolved, or C<undef> (or missing), in	178	L<aemp> commandline utility). The profile name can be specified via the
169	which case the noderef will be guessed.	179	named C<profile> parameter. If it is missing, then the nodename (F<uname
		180	-n>) will be used as profile name.
170		181
171	Afterwards, the node will bind itself on all endpoints and try to connect	182	The profile data is then gathered as follows:
172	to all additional C<$seednodes> that are specified. Seednodes are optional
173	and can be used to quickly bootstrap the node into an existing network.
174		183
175	=item slave nodes	184	First, all remaining key => value pairs (all of which are conviniently
		185	undocumented at the moment) will be interpreted as configuration
		186	data. Then they will be overwritten by any values specified in the global
		187	default configuration (see the F<aemp> utility), then the chain of
		188	profiles chosen by the profile name (and any C<parent> attributes).
176		189
177	When the C<$noderef> is the special string C<slave/>, then the node will	190	That means that the values specified in the profile have highest priority
178	become a slave node. Slave nodes cannot be contacted from outside and will	191	and the values specified directly via C<configure> have lowest priority,
179	route most of their traffic to the master node that they attach to.	192	and can only be used to specify defaults.
180		193
181	At least one additional noderef is required: The node will try to connect	194	If the profile specifies a node ID, then this will become the node ID of
182	to all of them and will become a slave attached to the first node it can	195	this process. If not, then the profile name will be used as node ID. The
183	successfully connect to.	196	special node ID of C<anon/> will be replaced by a random node ID.
		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.
184		215
185	=back	216	=back
186		217
187	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.
188	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.
189	server.
190		220
191	Example: become a public node listening on the default node.	221	configure
192		222
193	initialise_node;	223	Example: become an anonymous node. This form is often used for commandline
		224	clients.
194		225
195	Example: become a public node, and try to contact some well-known master	226	configure nodeid => "anon/";
196	servers to become part of the network.
197		227
198	initialise_node undef, "master1", "master2";	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).
199		231
200	Example: become a public node listening on port C<4041>.	232	# use the aemp commandline utility
		233	# aemp profile seed nodeid anon/ binds '*:4040'
201		234
202	initialise_node 4041;	235	# then use it
		236	configure profile => "seed";
203		237
204	Example: become a public node, only visible on localhost port 4044.	238	# or simply use aemp from the shell again:
		239	# aemp run profile seed
205		240
206	initialise_node "locahost:4044";	241	# or provide a nicer-to-remember nodeid
207		242	# aemp run profile seed nodeid "$(hostname)"
208	Example: become a slave node to any of the specified master servers.
209
210	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
211
212	=item $cv = resolve_node $noderef
213
214	Takes an unresolved node reference that may contain hostnames and
215	abbreviated IDs, resolves all of them and returns a resolved node
216	reference.
217
218	In addition to C<address:port> pairs allowed in resolved noderefs, the
219	following forms are supported:
220
221	=over 4
222
223	=item the empty string
224
225	An empty-string component gets resolved as if the default port (4040) was
226	specified.
227
228	=item naked port numbers (e.g. C<1234>)
229
230	These are resolved by prepending the local nodename and a colon, to be
231	further resolved.
232
233	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
234
235	These are resolved by using AnyEvent::DNS to resolve them, optionally
236	looking up SRV records for the C<aemp=4040> port, if no port was
237	specified.
238
239	=back
240		243
241	=item $SELF	244	=item $SELF
242		245
243	Contains the current port id while executing C<rcv> callbacks or C<psub>	246	Contains the current port id while executing C<rcv> callbacks or C<psub>
244	blocks.	247	blocks.
245		248
246	=item SELF, %SELF, @SELF...	249	=item *SELF, SELF, %SELF, @SELF...
247		250
248	Due to some quirks in how perl exports variables, it is impossible to	251	Due to some quirks in how perl exports variables, it is impossible to
249	just export C<$SELF>, all the symbols called C<SELF> are exported by this	252	just export C<$SELF>, all the symbols named C<SELF> are exported by this
250	module, but only C<$SELF> is currently used.	253	module, but only C<$SELF> is currently used.
251		254
252	=item snd $port, type => @data	255	=item snd $port, type => @data
253		256
254	=item snd $port, @msg	257	=item snd $port, @msg
255		258
256	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
257	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.
258	stringifies a sa port ID (such as a port object :).
259		261
260	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
261	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
262	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.
263		266
264	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
265	function: modifying any argument is not allowed and can cause many	268	function: modifying any argument (or values referenced by them) is
266	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.
267		273
268	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
269	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
270	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
271	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
272	node, anything can be passed.	278	node, anything can be passed. Best rely only on the common denominator of
		279	these.
273		280
274	=item $local_port = port	281	=item $local_port = port
275		282
276	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
277	matching port ("full port") or a single-callback port ("miniport"),	284	no callbacks set and will throw an error when it receives messages.
278	depending on how C<rcv> callbacks are bound to the object.
279		285
280	=item $port = port { my @msg = @_; $finished }	286	=item $local_port = port { my @msg = @_ }
281		287
282	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
283	matching behind it, and returns its ID. Semantically the same as creating
284	a port and calling C<rcv $port, $callback> on it.	289	creating a port and calling C<rcv $port, $callback> on it.
285		290
286	The block will be called for every message received on the port. When the	291	The block will be called for every message received on the port, with the
287	callback returns a true value its job is considered "done" and the port	292	global variable C<$SELF> set to the port ID. Runtime errors will cause the
288	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.
289		295
290	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:
291	be passed to the callback.
292		297
293	If you need the local port id in the callback, this works nicely:	298	my $port = port {
294		299	my @msg = @_;
295	my $port; $port = port {	300	...
296	snd $otherport, reply => $port;	301	kil $SELF;
297	};	302	};
298		303
299	=cut	304	=cut
300		305
301	sub rcv($@);	306	sub rcv($@);
		307
		308	sub _kilme {
		309	die "received message on port without callback";
		310	}
302		311
303	sub port(;&) {	312	sub port(;&) {
304	my $id = "$UNIQ." . $ID++;	313	my $id = "$UNIQ." . $ID++;
305	my $port = "$NODE#$id";	314	my $port = "$NODE#$id";
306		315
307	if (@_) {	316	rcv $port, shift \|\| \&_kilme;
308	rcv $port, shift;
309	} else {
310	$PORT{$id} = sub { }; # nop
311	}
312		317
313	$port	318	$port
314	}	319	}
315		320
316	=item reg $port, $name
317
318	=item reg $name
319
320	Registers the given port (or C<$SELF><<< if missing) under the name
321	C<$name>. If the name already exists it is replaced.
322
323	A port can only be registered under one well known name.
324
325	A port automatically becomes unregistered when it is killed.
326
327	=cut
328
329	sub reg(@) {
330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
331
332	$REG{$_[0]} = $port;
333	}
334
335	=item rcv $port, $callback->(@msg)	321	=item rcv $local_port, $callback->(@msg)
336		322
337	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
338	one if required).	324	remove the default callback: use C<sub { }> to disable it, or better
339		325	C<kil> the port when it is no longer needed.
340	=item rcv $port, tagstring => $callback->(@msg), ...
341
342	=item rcv $port, $smartmatch => $callback->(@msg), ...
343
344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
345
346	Register callbacks to be called on matching messages on the given full
347	port (after converting it to one if required) and return the port.
348
349	The callback has to return a true value when its work is done, after
350	which is will be removed, or a false value in which case it will stay
351	registered.
352		326
353	The global C<$SELF> (exported by this module) contains C<$port> while	327	The global C<$SELF> (exported by this module) contains C<$port> while
354	executing the callback.	328	executing the callback. Runtime errors during callback execution will
		329	result in the port being C<kil>ed.
355		330
356	Runtime errors during callback execution will result in the port being	331	The default callback received all messages not matched by a more specific
357	C<kil>ed.	332	C<tag> match.
358		333
359	If the match is an array reference, then it will be matched against the	334	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
360	first elements of the message, otherwise only the first element is being
361	matched.
362		335
363	Any element in the match that is specified as C<_any_> (a function	336	Register (or replace) callbacks to be called on messages starting with the
364	exported by this module) matches any single element of the message.	337	given tag on the given port (and return the port), or unregister it (when
		338	C<$callback> is C<$undef> or missing). There can only be one callback
		339	registered for each tag.
365		340
366	While not required, it is highly recommended that the first matching	341	The original message will be passed to the callback, after the first
367	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
368	also the most efficient match (by far).	343	environment as the default callback (see above).
369		344
370	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.
371		346
372	my $port = rcv port,	347	my $port = rcv port,
373	msg1 => sub { ...; 0 },	348	msg1 => sub { ... },
374	msg2 => sub { ...; 0 },	349	msg2 => sub { ... },
375	;	350	;
376		351
377	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
378	in one go:	353	in one go:
379		354
380	snd $otherport, reply =>	355	snd $otherport, reply =>
381	rcv port,	356	rcv port,
382	msg1 => sub { ...; 0 },	357	msg1 => sub { ... },
383	...	358	...
384	;	359	;
385		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, $otherport;
		368	};
		369
386	=cut	370	=cut
387		371
388	sub rcv($@) {	372	sub rcv($@) {
389	my $port = shift;	373	my $port = shift;
390	my ($noderef, $portid) = split /#/, $port, 2;	374	my ($nodeid, $portid) = split /#/, $port, 2;
391		375
392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	376	$NODE{$nodeid} == $NODE{""}
393	or Carp::croak "$port: rcv can only be called on local ports, caught";	377	or Carp::croak "$port: rcv can only be called on local ports, caught";
394		378
395	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 {
396	my $cb = shift;	387	my $cb = shift;
397	delete $PORT_DATA{$portid};
398	$PORT{$portid} = sub {	388	$PORT{$portid} = sub {
399	local $SELF = $port;	389	local $SELF = $port;
400	eval {	390	eval { &$cb }; _self_die if $@;
401	&$cb	391	};
402	and kil $port;
403	};	392	}
404	_self_die if $@;	393	} elsif (defined $_[0]) {
405	};
406	} else {
407	my $self = $PORT_DATA{$portid} \|\|= do {	394	my $self = $PORT_DATA{$portid} \|\|= do {
408	my $self = bless {	395	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
409	id => $port,
410	}, "AnyEvent::MP::Port";
411		396
412	$PORT{$portid} = sub {	397	$PORT{$portid} = sub {
413	local $SELF = $port;	398	local $SELF = $port;
414		399
415	eval {
416	for (@{ $self->{rc0}{$_[0]} }) {	400	if (my $cb = $self->[1]{$_[0]}) {
417	$_ && &{$_->[0]}	401	shift;
418	&& undef $_;	402	eval { &$cb }; _self_die if $@;
419	}	403	} else {
420
421	for (@{ $self->{rcv}{$_[0]} }) {
422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
423	&& &{$_->[0]}	404	&{ $self->[0] };
424	&& undef $_;
425	}
426
427	for (@{ $self->{any} }) {
428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
429	&& &{$_->[0]}
430	&& undef $_;
431	}	405	}
432	};	406	};
433	_self_die if $@;	407
		408	$self
434	};	409	};
435		410
436	$self
437	};
438
439	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	412	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
441		413
442	while (@_) {
443	my ($match, $cb) = splice @_, 0, 2;	414	my ($tag, $cb) = splice @_, 0, 2;
444		415
445	if (!ref $match) {	416	if (defined $cb) {
446	push @{ $self->{rc0}{$match} }, [$cb];	417	$self->[1]{$tag} = $cb;
447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
448	my ($type, @match) = @$match;
449	@match
450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
452	} else {	418	} else {
453	push @{ $self->{any} }, [$cb, $match];	419	delete $self->[1]{$tag};
454	}	420	}
455	}	421	}
456	}	422	}
457		423
458	$port	424	$port
…		…
494	$res	460	$res
495	}	461	}
496	}	462	}
497	}	463	}
498		464
499	=item $guard = mon $port, $cb->(@reason)	465	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
500		466
501	=item $guard = mon $port, $rcvport	467	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
502		468
503	=item $guard = mon $port	469	=item $guard = mon $port # kill $SELF when $port dies
504		470
505	=item $guard = mon $port, $rcvport, @msg	471	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
506		472
507	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
508	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
509	to stop monitoring again.	475	to stop monitoring again.
510		476
511	C<mon> effectively guarantees that, in the absence of hardware failures,	477	C<mon> effectively guarantees that, in the absence of hardware failures,
512	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
513	will arrive, or the monitoring action will be invoked after possible	479	arrive, or the monitoring action will be invoked after possible message
514	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
515	(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
516	port). After the monitoring action was invoked, further messages might get	482	port). After the monitoring action was invoked, further messages might get
517	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.
518		487
519	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
520	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
521	"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
522	C<eval> if unsure.	491	C<eval> if unsure.
…		…
552	mon $port, $self => "restart";	521	mon $port, $self => "restart";
553		522
554	=cut	523	=cut
555		524
556	sub mon {	525	sub mon {
557	my ($noderef, $port) = split /#/, shift, 2;	526	my ($nodeid, $port) = split /#/, shift, 2;
558		527
559	my $node = $NODE{$noderef} \|\| add_node $noderef;	528	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
560		529
561	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,';
562		531
563	unless (ref $cb) {	532	unless (ref $cb) {
564	if (@_) {	533	if (@_) {
…		…
584	is killed, the references will be freed.	553	is killed, the references will be freed.
585		554
586	Optionally returns a guard that will stop the monitoring.	555	Optionally returns a guard that will stop the monitoring.
587		556
588	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
589	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>):
590		559
591	$port->rcv (start => sub {	560	$port->rcv (start => sub {
592	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	561	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
593	undef $timer if 0.9 < rand;	562	undef $timer if 0.9 < rand;
594	});	563	});
595	});	564	});
596		565
597	=cut	566	=cut
…		…
606		575
607	=item kil $port[, @reason]	576	=item kil $port[, @reason]
608		577
609	Kill the specified port with the given C<@reason>.	578	Kill the specified port with the given C<@reason>.
610		579
611	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
612	ports will not be kileld, or even notified).	581	monitoring other ports will not necessarily die because a port dies
		582	"normally").
613		583
614	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
615	C<mon>, see below).	585	C<mon>, see above).
616		586
617	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
618	will be reported as reason C<< die => $@ >>.	588	will be reported as reason C<< die => $@ >>.
619		589
620	Transport/communication errors are reported as C<< transport_error =>	590	Transport/communication errors are reported as C<< transport_error =>
…		…
625	=item $port = spawn $node, $initfunc[, @initdata]	595	=item $port = spawn $node, $initfunc[, @initdata]
626		596
627	Creates a port on the node C<$node> (which can also be a port ID, in which	597	Creates a port on the node C<$node> (which can also be a port ID, in which
628	case it's the node where that port resides).	598	case it's the node where that port resides).
629		599
630	The port ID of the newly created port is return immediately, and it is	600	The port ID of the newly created port is returned immediately, and it is
631	permissible to immediately start sending messages or monitor the port.	601	possible to immediately start sending messages or to monitor the port.
632		602
633	After the port has been created, the init function is	603	After the port has been created, the init function is called on the remote
634	called. This function must be a fully-qualified function name	604	node, in the same context as a C<rcv> callback. This function must be a
635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	605	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
636	program, use C<::name>.	606	specify a function in the main program, use C<::name>.
637		607
638	If the function doesn't exist, then the node tries to C<require>	608	If the function doesn't exist, then the node tries to C<require>
639	the package, then the package above the package and so on (e.g.	609	the package, then the package above the package and so on (e.g.
640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	610	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
641	exists or it runs out of package names.	611	exists or it runs out of package names.
642		612
643	The init function is then called with the newly-created port as context	613	The init function is then called with the newly-created port as context
644	object (C<$SELF>) and the C<@initdata> values as arguments.	614	object (C<$SELF>) and the C<@initdata> values as arguments.
645		615
646	A common idiom is to pass your own port, monitor the spawned port, and	616	A common idiom is to pass a local port, immediately monitor the spawned
647	in the init function, monitor the original port. This two-way monitoring	617	port, and in the remote init function, immediately monitor the passed
648	ensures that both ports get cleaned up when there is a problem.	618	local port. This two-way monitoring ensures that both ports get cleaned up
		619	when there is a problem.
649		620
650	Example: spawn a chat server port on C<$othernode>.	621	Example: spawn a chat server port on C<$othernode>.
651		622
652	# this node, executed from within a port context:	623	# this node, executed from within a port context:
653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	624	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
676	};	647	};
677	_self_die if $@;	648	_self_die if $@;
678	}	649	}
679		650
680	sub spawn(@) {	651	sub spawn(@) {
681	my ($noderef, undef) = split /#/, shift, 2;	652	my ($nodeid, undef) = split /#/, shift, 2;
682		653
683	my $id = "$RUNIQ." . $ID++;	654	my $id = "$RUNIQ." . $ID++;
684		655
685	$_[0] =~ /::/	656	$_[0] =~ /::/
686	or Carp::croak "spawn init function must be a fully-qualified name, caught";	657	or Carp::croak "spawn init function must be a fully-qualified name, caught";
687		658
688	($NODE{$noderef} \|\| add_node $noderef)	659	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
690		660
691	"$noderef#$id"	661	"$nodeid#$id"
692	}	662	}
693		663
694	=back	664	=item after $timeout, @msg
695		665
696	=head1 NODE MESSAGES	666	=item after $timeout, $callback
697		667
698	Nodes understand the following messages sent to them. Many of them take	668	Either sends the given message, or call the given callback, after the
699	arguments called C<@reply>, which will simply be used to compose a reply	669	specified number of seconds.
700	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
701	the remaining arguments are simply the message data.
702		670
703	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.
704		674
705	=over 4
706
707	=cut	675	=cut
708		676
709	=item lookup => $name, @reply	677	sub after($@) {
		678	my ($timeout, @action) = @_;
710		679
711	Replies with the port ID of the specified well-known port, or C<undef>.	680	my $t; $t = AE::timer $timeout, 0, sub {
712		681	undef $t;
713	=item devnull => ...	682	ref $action[0]
714		683	? $action[0]()
715	Generic data sink/CPU heat conversion.	684	: snd @action;
716		685	};
717	=item relay => $port, @msg	686	}
718
719	Simply forwards the message to the given port.
720
721	=item eval => $string[ @reply]
722
723	Evaluates the given string. If C<@reply> is given, then a message of the
724	form C<@reply, $@, @evalres> is sent.
725
726	Example: crash another node.
727
728	snd $othernode, eval => "exit";
729
730	=item time => @reply
731
732	Replies the the current node time to C<@reply>.
733
734	Example: tell the current node to send the current time to C<$myport> in a
735	C<timereply> message.
736
737	snd $NODE, time => $myport, timereply => 1, 2;
738	# => snd $myport, timereply => 1, 2, <time>
739		687
740	=back	688	=back
741		689
742	=head1 AnyEvent::MP vs. Distributed Erlang	690	=head1 AnyEvent::MP vs. Distributed Erlang
743		691
…		…
753		701
754	Despite the similarities, there are also some important differences:	702	Despite the similarities, there are also some important differences:
755		703
756	=over 4	704	=over 4
757		705
758	=item * Node references contain the recipe on how to contact them.	706	=item * Node IDs are arbitrary strings in AEMP.
759		707
760	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
761	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
762	convenience functionality.	710	configuraiton or DNS), but will otherwise discover other odes itself.
763		711
764	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
765	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.
766		726
767	=item * Erlang uses processes and a mailbox, AEMP does not queue.	727	=item * Erlang uses processes and a mailbox, AEMP does not queue.
768		728
769	Erlang uses processes that selctively receive messages, and therefore	729	Erlang uses processes that selectively receive messages, and therefore
770	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
771	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.
772		734
773	(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).
774		736
775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	737	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
776		738
777	Sending messages in Erlang is synchronous and blocks the process. AEMP	739	Sending messages in Erlang is synchronous and blocks the process (and
778	sends are immediate, connection establishment is handled in the	740	so does not need a queue that can overflow). AEMP sends are immediate,
779	background.	741	connection establishment is handled in the background.
780		742
781	=item * Erlang can silently lose messages, AEMP cannot.	743	=item * Erlang suffers from silent message loss, AEMP does not.
782		744
783	Erlang makes few guarantees on messages delivery - messages can get lost	745	Erlang makes few guarantees on messages delivery - messages can get lost
784	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,
785	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).
786		748
787	AEMP guarantees correct ordering, and the guarantee that there are no	749	AEMP guarantees correct ordering, and the guarantee that after one message
788	holes in the message sequence.	750	is lost, all following ones sent to the same port are lost as well, until
789		751	monitoring raises an error, so there are no silent "holes" in the message
790	=item * In Erlang, processes can be declared dead and later be found to be	752	sequence.
791	alive.
792
793	In Erlang it can happen that a monitored process is declared dead and
794	linked processes get killed, but later it turns out that the process is
795	still alive - and can receive messages.
796
797	In AEMP, when port monitoring detects a port as dead, then that port will
798	eventually be killed - it cannot happen that a node detects a port as dead
799	and then later sends messages to it, finding it is still alive.
800		753
801	=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.
802		755
803	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
804	ID known to other nodes for a completely different process, causing	757	known to other nodes for a completely different process, causing messages
805	messages destined for that process to end up in an unrelated process.	758	destined for that process to end up in an unrelated process.
806		759
807	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
808	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.
809		762
810	=item * Erlang uses unprotected connections, AEMP uses secure	763	=item * Erlang uses unprotected connections, AEMP uses secure
811	authentication and can use TLS.	764	authentication and can use TLS.
812		765
813	AEMP can use a proven protocol - SSL/TLS - to protect connections and	766	AEMP can use a proven protocol - TLS - to protect connections and
814	securely authenticate nodes.	767	securely authenticate nodes.
815		768
816	=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
817	communications.	770	communications.
818		771
819	The AEMP protocol, unlike the Erlang protocol, supports both	772	The AEMP protocol, unlike the Erlang protocol, supports both programming
820	language-independent text-only protocols (good for debugging) and binary,	773	language independent text-only protocols (good for debugging) and binary,
821	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.
822		776
823	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
824	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
825	protocol simple.	779	protocol simple.
826		780
827	=item * AEMP has more flexible monitoring options than Erlang.	781	=item * AEMP has more flexible monitoring options than Erlang.
828		782
829	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
…		…
832	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
833	on a per-process basis.	787	on a per-process basis.
834		788
835	=item * Erlang tries to hide remote/local connections, AEMP does not.	789	=item * Erlang tries to hide remote/local connections, AEMP does not.
836		790
837	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
838	as linking is (except linking is unreliable in Erlang).	792	same way as linking is (except linking is unreliable in Erlang).
839		793
840	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
841	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
842	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
843	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
844	more reliable.	798	reliable (no need for C<spawn_link>).
845		799
846	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
847	(hard to do in Erlang).	801	(hard to do in Erlang).
848		802
849	=back	803	=back
850		804
		805	=head1 RATIONALE
		806
		807	=over 4
		808
		809	=item Why strings for port and node IDs, why not objects?
		810
		811	We considered "objects", but found that the actual number of methods
		812	that can be called are quite low. Since port and node IDs travel over
		813	the network frequently, the serialising/deserialising would add lots of
		814	overhead, as well as having to keep a proxy object everywhere.
		815
		816	Strings can easily be printed, easily serialised etc. and need no special
		817	procedures to be "valid".
		818
		819	And as a result, a miniport consists of a single closure stored in a
		820	global hash - it can't become much cheaper.
		821
		822	=item Why favour JSON, why not a real serialising format such as Storable?
		823
		824	In fact, any AnyEvent::MP node will happily accept Storable as framing
		825	format, but currently there is no way to make a node use Storable by
		826	default (although all nodes will accept it).
		827
		828	The default framing protocol is JSON because a) JSON::XS is many times
		829	faster for small messages and b) most importantly, after years of
		830	experience we found that object serialisation is causing more problems
		831	than it solves: Just like function calls, objects simply do not travel
		832	easily over the network, mostly because they will always be a copy, so you
		833	always have to re-think your design.
		834
		835	Keeping your messages simple, concentrating on data structures rather than
		836	objects, will keep your messages clean, tidy and efficient.
		837
		838	=back
		839
851	=head1 SEE ALSO	840	=head1 SEE ALSO
		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.
852		848
853	L<AnyEvent>.	849	L<AnyEvent>.
854		850
855	=head1 AUTHOR	851	=head1 AUTHOR
856		852

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC vs. Revision 1.76 by root, Mon Aug 31 18:45:05 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC vs.
Revision 1.76 by root, Mon Aug 31 18:45:05 2009 UTC