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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 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 - explains 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
…		…
105		121
106	=cut	122	=cut
107		123
108	package AnyEvent::MP;	124	package AnyEvent::MP;
109		125
110	use AnyEvent::MP::Base;	126	use AnyEvent::MP::Kernel;
111		127
112	use common::sense;	128	use common::sense;
113		129
114	use Carp ();	130	use Carp ();
115		131
116	use AE ();	132	use AE ();
117		133
118	use base "Exporter";	134	use base "Exporter";
119		135
120	our $VERSION = $AnyEvent::MP::Base::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 $profile, key => value...
149		164
150	=item initialise_node "slave/", $master, $master...	165	=item configure key => value...
151		166
152	Before a node can talk to other nodes on the network it has to initialise	167	Before a node can talk to other nodes on the network (i.e. enter
153	itself - the minimum a node needs to know is it's own name, and optionally	168	"distributed mode") it has to configure itself - the minimum a node needs
154	it should know the noderefs of some other nodes in the network.	169	to know is its own name, and optionally it should know the addresses of
		170	some other nodes in the network to discover other nodes.
155		171
156	This function initialises a node - it must be called exactly once (or	172	This function configures a node - it must be called exactly once (or
157	never) before calling other AnyEvent::MP functions.	173	never) before calling other AnyEvent::MP functions.
158		174
159	All arguments are noderefs, which can be either resolved or unresolved.
160
161	There are two types of networked nodes, public nodes and slave nodes:
162
163	=over 4	175	=over 4
164		176
165	=item public nodes	177	=item step 1, gathering configuration from profiles
166		178
167	For public nodes, C<$noderef> must either be a (possibly unresolved)	179	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	180	L<aemp> commandline utility). The profile name can be specified via the
169	which case the noderef will be guessed.	181	named C<profile> parameter or can simply be the first parameter). If it is
		182	missing, then the nodename (F<uname -n>) will be used as profile name.
170		183
171	Afterwards, the node will bind itself on all endpoints and try to connect	184	The profile data is then gathered as follows:
172	to all additional C<$seednodes> that are specified. Seednodes are optional
173	and can be used to quickly bootstrap the node into an existing network.
174		185
175	=item slave nodes	186	First, all remaining key => value pairs (all of which are conveniently
		187	undocumented at the moment) will be interpreted as configuration
		188	data. Then they will be overwritten by any values specified in the global
		189	default configuration (see the F<aemp> utility), then the chain of
		190	profiles chosen by the profile name (and any C<parent> attributes).
176		191
177	When the C<$noderef> is the special string C<slave/>, then the node will	192	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	193	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.	194	and can only be used to specify defaults.
180		195
181	At least one additional noderef is required: The node will try to connect	196	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	197	this process. If not, then the profile name will be used as node ID. The
183	successfully connect to.	198	special node ID of C<anon/> will be replaced by a random node ID.
		199
		200	=item step 2, bind listener sockets
		201
		202	The next step is to look up the binds in the profile, followed by binding
		203	aemp protocol listeners on all binds specified (it is possible and valid
		204	to have no binds, meaning that the node cannot be contacted form the
		205	outside. This means the node cannot talk to other nodes that also have no
		206	binds, but it can still talk to all "normal" nodes).
		207
		208	If the profile does not specify a binds list, then a default of C<*> is
		209	used, meaning the node will bind on a dynamically-assigned port on every
		210	local IP address it finds.
		211
		212	=item step 3, connect to seed nodes
		213
		214	As the last step, the seeds list from the profile is passed to the
		215	L<AnyEvent::MP::Global> module, which will then use it to keep
		216	connectivity with at least one node at any point in time.
184		217
185	=back	218	=back
186		219
187	This function will block until all nodes have been resolved and, for slave	220	Example: become a distributed node using the locla node name as profile.
188	nodes, until it has successfully established a connection to a master	221	This should be the most common form of invocation for "daemon"-type nodes.
189	server.
190		222
191	Example: become a public node listening on the default node.	223	configure
192		224
193	initialise_node;	225	Example: become an anonymous node. This form is often used for commandline
		226	clients.
194		227
195	Example: become a public node, and try to contact some well-known master	228	configure nodeid => "anon/";
196	servers to become part of the network.
197		229
198	initialise_node undef, "master1", "master2";	230	Example: configure a node using a profile called seed, which si suitable
		231	for a seed node as it binds on all local addresses on a fixed port (4040,
		232	customary for aemp).
199		233
200	Example: become a public node listening on port C<4041>.	234	# use the aemp commandline utility
		235	# aemp profile seed nodeid anon/ binds '*:4040'
201		236
202	initialise_node 4041;	237	# then use it
		238	configure profile => "seed";
203		239
204	Example: become a public node, only visible on localhost port 4044.	240	# or simply use aemp from the shell again:
		241	# aemp run profile seed
205		242
206	initialise_node "locahost:4044";	243	# or provide a nicer-to-remember nodeid
207		244	# 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		245
241	=item $SELF	246	=item $SELF
242		247
243	Contains the current port id while executing C<rcv> callbacks or C<psub>	248	Contains the current port id while executing C<rcv> callbacks or C<psub>
244	blocks.	249	blocks.
245		250
246	=item SELF, %SELF, @SELF...	251	=item *SELF, SELF, %SELF, @SELF...
247		252
248	Due to some quirks in how perl exports variables, it is impossible to	253	Due to some quirks in how perl exports variables, it is impossible to
249	just export C<$SELF>, all the symbols called C<SELF> are exported by this	254	just export C<$SELF>, all the symbols named C<SELF> are exported by this
250	module, but only C<$SELF> is currently used.	255	module, but only C<$SELF> is currently used.
251		256
252	=item snd $port, type => @data	257	=item snd $port, type => @data
253		258
254	=item snd $port, @msg	259	=item snd $port, @msg
255		260
256	Send the given message to the given port ID, which can identify either	261	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	262	local or a remote port, and must be a port ID.
258	stringifies a sa port ID (such as a port object :).
259		263
260	While the message can be about anything, it is highly recommended to use a	264	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	265	use a string as first element (a port ID, or some word that indicates a
262	type etc.).	266	request type etc.) and to consist if only simple perl values (scalars,
		267	arrays, hashes) - if you think you need to pass an object, think again.
263		268
264	The message data effectively becomes read-only after a call to this	269	The message data logically becomes read-only after a call to this
265	function: modifying any argument is not allowed and can cause many	270	function: modifying any argument (or values referenced by them) is
266	problems.	271	forbidden, as there can be considerable time between the call to C<snd>
		272	and the time the message is actually being serialised - in fact, it might
		273	never be copied as within the same process it is simply handed to the
		274	receiving port.
267		275
268	The type of data you can transfer depends on the transport protocol: when	276	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	277	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	278	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	279	that Storable can serialise and deserialise is allowed, and for the local
272	node, anything can be passed.	280	node, anything can be passed. Best rely only on the common denominator of
		281	these.
273		282
274	=item $local_port = port	283	=item $local_port = port
275		284
276	Create a new local port object that can be used either as a pattern	285	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"),	286	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		287
280	=item $port = port { my @msg = @_; $finished }	288	=item $local_port = port { my @msg = @_ }
281		289
282	Creates a "miniport", that is, a very lightweight port without any pattern	290	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.	291	creating a port and calling C<rcv $port, $callback> on it.
285		292
286	The block will be called for every message received on the port. When the	293	The block will be called for every message received on the port, with the
287	callback returns a true value its job is considered "done" and the port	294	global variable C<$SELF> set to the port ID. Runtime errors will cause the
288	will be destroyed. Otherwise it will stay alive.	295	port to be C<kil>ed. The message will be passed as-is, no extra argument
		296	(i.e. no port ID) will be passed to the callback.
289		297
290	The message will be passed as-is, no extra argument (i.e. no port id) will	298	If you want to stop/destroy the port, simply C<kil> it:
291	be passed to the callback.
292		299
293	If you need the local port id in the callback, this works nicely:	300	my $port = port {
294		301	my @msg = @_;
295	my $port; $port = port {	302	...
296	snd $otherport, reply => $port;	303	kil $SELF;
297	};	304	};
298		305
299	=cut	306	=cut
300		307
301	sub rcv($@);	308	sub rcv($@);
		309
		310	sub _kilme {
		311	die "received message on port without callback";
		312	}
302		313
303	sub port(;&) {	314	sub port(;&) {
304	my $id = "$UNIQ." . $ID++;	315	my $id = "$UNIQ." . $ID++;
305	my $port = "$NODE#$id";	316	my $port = "$NODE#$id";
306		317
307	if (@_) {	318	rcv $port, shift \|\| \&_kilme;
308	rcv $port, shift;
309	} else {
310	$PORT{$id} = sub { }; # nop
311	}
312		319
313	$port	320	$port
314	}	321	}
315		322
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)	323	=item rcv $local_port, $callback->(@msg)
336		324
337	Replaces the callback on the specified miniport (after converting it to	325	Replaces the default callback on the specified port. There is no way to
338	one if required).	326	remove the default callback: use C<sub { }> to disable it, or better
339		327	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...] => $callback->(@msg), ...
345
346	Register callbacks to be called on matching messages on the given full
347	port (after converting it to one if required) and return the port.
348
349	The callback has to return a true value when its work is done, after
350	which is will be removed, or a false value in which case it will stay
351	registered.
352		328
353	The global C<$SELF> (exported by this module) contains C<$port> while	329	The global C<$SELF> (exported by this module) contains C<$port> while
354	executing the callback.	330	executing the callback. Runtime errors during callback execution will
		331	result in the port being C<kil>ed.
355		332
356	Runtime errors during callback execution will result in the port being	333	The default callback received all messages not matched by a more specific
357	C<kil>ed.	334	C<tag> match.
358		335
359	If the match is an array reference, then it will be matched against the	336	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
360	first elements of the message, otherwise only the first element is being
361	matched.
362		337
363	Any element in the match that is specified as C<_any_> (a function	338	Register (or replace) callbacks to be called on messages starting with the
364	exported by this module) matches any single element of the message.	339	given tag on the given port (and return the port), or unregister it (when
		340	C<$callback> is C<$undef> or missing). There can only be one callback
		341	registered for each tag.
365		342
366	While not required, it is highly recommended that the first matching	343	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	344	element (the tag) has been removed. The callback will use the same
368	also the most efficient match (by far).	345	environment as the default callback (see above).
369		346
370	Example: create a port and bind receivers on it in one go.	347	Example: create a port and bind receivers on it in one go.
371		348
372	my $port = rcv port,	349	my $port = rcv port,
373	msg1 => sub { ...; 0 },	350	msg1 => sub { ... },
374	msg2 => sub { ...; 0 },	351	msg2 => sub { ... },
375	;	352	;
376		353
377	Example: create a port, bind receivers and send it in a message elsewhere	354	Example: create a port, bind receivers and send it in a message elsewhere
378	in one go:	355	in one go:
379		356
380	snd $otherport, reply =>	357	snd $otherport, reply =>
381	rcv port,	358	rcv port,
382	msg1 => sub { ...; 0 },	359	msg1 => sub { ... },
383	...	360	...
384	;	361	;
385		362
		363	Example: temporarily register a rcv callback for a tag matching some port
		364	(e.g. for a rpc reply) and unregister it after a message was received.
		365
		366	rcv $port, $otherport => sub {
		367	my @reply = @_;
		368
		369	rcv $SELF, $otherport;
		370	};
		371
386	=cut	372	=cut
387		373
388	sub rcv($@) {	374	sub rcv($@) {
389	my $port = shift;	375	my $port = shift;
390	my ($noderef, $portid) = split /#/, $port, 2;	376	my ($nodeid, $portid) = split /#/, $port, 2;
391		377
392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	378	$NODE{$nodeid} == $NODE{""}
393	or Carp::croak "$port: rcv can only be called on local ports, caught";	379	or Carp::croak "$port: rcv can only be called on local ports, caught";
394		380
395	if (@_ == 1) {	381	while (@_) {
		382	if (ref $_[0]) {
		383	if (my $self = $PORT_DATA{$portid}) {
		384	"AnyEvent::MP::Port" eq ref $self
		385	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		386
		387	$self->[2] = shift;
		388	} else {
396	my $cb = shift;	389	my $cb = shift;
397	delete $PORT_DATA{$portid};
398	$PORT{$portid} = sub {	390	$PORT{$portid} = sub {
399	local $SELF = $port;	391	local $SELF = $port;
400	eval {	392	eval { &$cb }; _self_die if $@;
401	&$cb	393	};
402	and kil $port;
403	};	394	}
404	_self_die if $@;	395	} elsif (defined $_[0]) {
405	};
406	} else {
407	my $self = $PORT_DATA{$portid} \|\|= do {	396	my $self = $PORT_DATA{$portid} \|\|= do {
408	my $self = bless {	397	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
409	id => $port,
410	}, "AnyEvent::MP::Port";
411		398
412	$PORT{$portid} = sub {	399	$PORT{$portid} = sub {
413	local $SELF = $port;	400	local $SELF = $port;
414		401
415	eval {
416	for (@{ $self->{rc0}{$_[0]} }) {	402	if (my $cb = $self->[1]{$_[0]}) {
417	$_ && &{$_->[0]}	403	shift;
418	&& undef $_;	404	eval { &$cb }; _self_die if $@;
419	}	405	} else {
420
421	for (@{ $self->{rcv}{$_[0]} }) {
422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
423	&& &{$_->[0]}	406	&{ $self->[0] };
424	&& undef $_;
425	}
426
427	for (@{ $self->{any} }) {
428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
429	&& &{$_->[0]}
430	&& undef $_;
431	}	407	}
432	};	408	};
433	_self_die if $@;	409
		410	$self
434	};	411	};
435		412
436	$self
437	};
438
439	"AnyEvent::MP::Port" eq ref $self	413	"AnyEvent::MP::Port" eq ref $self
440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
441		415
442	while (@_) {
443	my ($match, $cb) = splice @_, 0, 2;	416	my ($tag, $cb) = splice @_, 0, 2;
444		417
445	if (!ref $match) {	418	if (defined $cb) {
446	push @{ $self->{rc0}{$match} }, [$cb];	419	$self->[1]{$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 {	420	} else {
453	push @{ $self->{any} }, [$cb, $match];	421	delete $self->[1]{$tag};
454	}	422	}
455	}	423	}
456	}	424	}
457		425
458	$port	426	$port
…		…
494	$res	462	$res
495	}	463	}
496	}	464	}
497	}	465	}
498		466
499	=item $guard = mon $port, $cb->(@reason)	467	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
500		468
501	=item $guard = mon $port, $rcvport	469	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
502		470
503	=item $guard = mon $port	471	=item $guard = mon $port # kill $SELF when $port dies
504		472
505	=item $guard = mon $port, $rcvport, @msg	473	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
506		474
507	Monitor the given port and do something when the port is killed or	475	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	476	messages to it were lost, and optionally return a guard that can be used
509	to stop monitoring again.	477	to stop monitoring again.
510		478
511	C<mon> effectively guarantees that, in the absence of hardware failures,	479	C<mon> effectively guarantees that, in the absence of hardware failures,
512	that after starting the monitor, either all messages sent to the port	480	after starting the monitor, either all messages sent to the port will
513	will arrive, or the monitoring action will be invoked after possible	481	arrive, or the monitoring action will be invoked after possible message
514	message loss has been detected. No messages will be lost "in between"	482	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	483	the first lost message no further messages will be received by the
516	port). After the monitoring action was invoked, further messages might get	484	port). After the monitoring action was invoked, further messages might get
517	delivered again.	485	delivered again.
		486
		487	Note that monitoring-actions are one-shot: once messages are lost (and a
		488	monitoring alert was raised), they are removed and will not trigger again.
518		489
519	In the first form (callback), the callback is simply called with any	490	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	491	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	492	"normally"). Note also that I<< the callback B<must> never die >>, so use
522	C<eval> if unsure.	493	C<eval> if unsure.
523		494
524	In the second form (another port given), the other port (C<$rcvport>)	495	In the second form (another port given), the other port (C<$rcvport>)
525	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	496	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
526	"normal" kils nothing happens, while under all other conditions, the other	497	"normal" kils nothing happens, while under all other conditions, the other
527	port is killed with the same reason.	498	port is killed with the same reason.
528		499
529	The third form (kill self) is the same as the second form, except that	500	The third form (kill self) is the same as the second form, except that
530	C<$rvport> defaults to C<$SELF>.	501	C<$rvport> defaults to C<$SELF>.
…		…
533	C<snd>.	504	C<snd>.
534		505
535	As a rule of thumb, monitoring requests should always monitor a port from	506	As a rule of thumb, monitoring requests should always monitor a port from
536	a local port (or callback). The reason is that kill messages might get	507	a local port (or callback). The reason is that kill messages might get
537	lost, just like any other message. Another less obvious reason is that	508	lost, just like any other message. Another less obvious reason is that
538	even monitoring requests can get lost (for exmaple, when the connection	509	even monitoring requests can get lost (for example, when the connection
539	to the other node goes down permanently). When monitoring a port locally	510	to the other node goes down permanently). When monitoring a port locally
540	these problems do not exist.	511	these problems do not exist.
541		512
542	Example: call a given callback when C<$port> is killed.	513	Example: call a given callback when C<$port> is killed.
543		514
…		…
552	mon $port, $self => "restart";	523	mon $port, $self => "restart";
553		524
554	=cut	525	=cut
555		526
556	sub mon {	527	sub mon {
557	my ($noderef, $port) = split /#/, shift, 2;	528	my ($nodeid, $port) = split /#/, shift, 2;
558		529
559	my $node = $NODE{$noderef} \|\| add_node $noderef;	530	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
560		531
561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	532	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
562		533
563	unless (ref $cb) {	534	unless (ref $cb) {
564	if (@_) {	535	if (@_) {
…		…
584	is killed, the references will be freed.	555	is killed, the references will be freed.
585		556
586	Optionally returns a guard that will stop the monitoring.	557	Optionally returns a guard that will stop the monitoring.
587		558
588	This function is useful when you create e.g. timers or other watchers and	559	This function is useful when you create e.g. timers or other watchers and
589	want to free them when the port gets killed:	560	want to free them when the port gets killed (note the use of C<psub>):
590		561
591	$port->rcv (start => sub {	562	$port->rcv (start => sub {
592	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	563	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
593	undef $timer if 0.9 < rand;	564	undef $timer if 0.9 < rand;
594	});	565	});
595	});	566	});
596		567
597	=cut	568	=cut
…		…
606		577
607	=item kil $port[, @reason]	578	=item kil $port[, @reason]
608		579
609	Kill the specified port with the given C<@reason>.	580	Kill the specified port with the given C<@reason>.
610		581
611	If no C<@reason> is specified, then the port is killed "normally" (linked	582	If no C<@reason> is specified, then the port is killed "normally" (ports
612	ports will not be kileld, or even notified).	583	monitoring other ports will not necessarily die because a port dies
		584	"normally").
613		585
614	Otherwise, linked ports get killed with the same reason (second form of	586	Otherwise, linked ports get killed with the same reason (second form of
615	C<mon>, see below).	587	C<mon>, see above).
616		588
617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	589	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
618	will be reported as reason C<< die => $@ >>.	590	will be reported as reason C<< die => $@ >>.
619		591
620	Transport/communication errors are reported as C<< transport_error =>	592	Transport/communication errors are reported as C<< transport_error =>
…		…
625	=item $port = spawn $node, $initfunc[, @initdata]	597	=item $port = spawn $node, $initfunc[, @initdata]
626		598
627	Creates a port on the node C<$node> (which can also be a port ID, in which	599	Creates a port on the node C<$node> (which can also be a port ID, in which
628	case it's the node where that port resides).	600	case it's the node where that port resides).
629		601
630	The port ID of the newly created port is return immediately, and it is	602	The port ID of the newly created port is returned immediately, and it is
631	permissible to immediately start sending messages or monitor the port.	603	possible to immediately start sending messages or to monitor the port.
632		604
633	After the port has been created, the init function is	605	After the port has been created, the init function is called on the remote
634	called. This function must be a fully-qualified function name	606	node, in the same context as a C<rcv> callback. This function must be a
635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	607	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
636	program, use C<::name>.	608	specify a function in the main program, use C<::name>.
637		609
638	If the function doesn't exist, then the node tries to C<require>	610	If the function doesn't exist, then the node tries to C<require>
639	the package, then the package above the package and so on (e.g.	611	the package, then the package above the package and so on (e.g.
640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	612	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
641	exists or it runs out of package names.	613	exists or it runs out of package names.
642		614
643	The init function is then called with the newly-created port as context	615	The init function is then called with the newly-created port as context
644	object (C<$SELF>) and the C<@initdata> values as arguments.	616	object (C<$SELF>) and the C<@initdata> values as arguments.
645		617
646	A common idiom is to pass your own port, monitor the spawned port, and	618	A common idiom is to pass a local port, immediately monitor the spawned
647	in the init function, monitor the original port. This two-way monitoring	619	port, and in the remote init function, immediately monitor the passed
648	ensures that both ports get cleaned up when there is a problem.	620	local port. This two-way monitoring ensures that both ports get cleaned up
		621	when there is a problem.
649		622
650	Example: spawn a chat server port on C<$othernode>.	623	Example: spawn a chat server port on C<$othernode>.
651		624
652	# this node, executed from within a port context:	625	# this node, executed from within a port context:
653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	626	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
676	};	649	};
677	_self_die if $@;	650	_self_die if $@;
678	}	651	}
679		652
680	sub spawn(@) {	653	sub spawn(@) {
681	my ($noderef, undef) = split /#/, shift, 2;	654	my ($nodeid, undef) = split /#/, shift, 2;
682		655
683	my $id = "$RUNIQ." . $ID++;	656	my $id = "$RUNIQ." . $ID++;
684		657
685	$_[0] =~ /::/	658	$_[0] =~ /::/
686	or Carp::croak "spawn init function must be a fully-qualified name, caught";	659	or Carp::croak "spawn init function must be a fully-qualified name, caught";
687		660
688	($NODE{$noderef} \|\| add_node $noderef)	661	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
690		662
691	"$noderef#$id"	663	"$nodeid#$id"
692	}	664	}
693		665
694	=back	666	=item after $timeout, @msg
695		667
696	=head1 NODE MESSAGES	668	=item after $timeout, $callback
697		669
698	Nodes understand the following messages sent to them. Many of them take	670	Either sends the given message, or call the given callback, after the
699	arguments called C<@reply>, which will simply be used to compose a reply	671	specified number of seconds.
700	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
701	the remaining arguments are simply the message data.
702		672
703	While other messages exist, they are not public and subject to change.	673	This is simply a utility function that comes in handy at times - the
		674	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		675	so it may go away in the future.
704		676
705	=over 4
706
707	=cut	677	=cut
708		678
709	=item lookup => $name, @reply	679	sub after($@) {
		680	my ($timeout, @action) = @_;
710		681
711	Replies with the port ID of the specified well-known port, or C<undef>.	682	my $t; $t = AE::timer $timeout, 0, sub {
712		683	undef $t;
713	=item devnull => ...	684	ref $action[0]
714		685	? $action[0]()
715	Generic data sink/CPU heat conversion.	686	: snd @action;
716		687	};
717	=item relay => $port, @msg	688	}
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		689
740	=back	690	=back
741		691
742	=head1 AnyEvent::MP vs. Distributed Erlang	692	=head1 AnyEvent::MP vs. Distributed Erlang
743		693
…		…
753		703
754	Despite the similarities, there are also some important differences:	704	Despite the similarities, there are also some important differences:
755		705
756	=over 4	706	=over 4
757		707
758	=item * Node references contain the recipe on how to contact them.	708	=item * Node IDs are arbitrary strings in AEMP.
759		709
760	Erlang relies on special naming and DNS to work everywhere in the	710	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	711	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
762	convenience functionality.	712	configuration or DNS), but will otherwise discover other odes itself.
763		713
764	This means that AEMP requires a less tightly controlled environment at the	714	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
765	cost of longer node references and a slightly higher management overhead.	715	uses "local ports are like remote ports".
		716
		717	The failure modes for local ports are quite different (runtime errors
		718	only) then for remote ports - when a local port dies, you I<know> it dies,
		719	when a connection to another node dies, you know nothing about the other
		720	port.
		721
		722	Erlang pretends remote ports are as reliable as local ports, even when
		723	they are not.
		724
		725	AEMP encourages a "treat remote ports differently" philosophy, with local
		726	ports being the special case/exception, where transport errors cannot
		727	occur.
766		728
767	=item * Erlang uses processes and a mailbox, AEMP does not queue.	729	=item * Erlang uses processes and a mailbox, AEMP does not queue.
768		730
769	Erlang uses processes that selctively receive messages, and therefore	731	Erlang uses processes that selectively receive messages, and therefore
770	needs a queue. AEMP is event based, queuing messages would serve no useful	732	needs a queue. AEMP is event based, queuing messages would serve no
771	purpose.	733	useful purpose. For the same reason the pattern-matching abilities of
		734	AnyEvent::MP are more limited, as there is little need to be able to
		735	filter messages without dequeuing them.
772		736
773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	737	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
774		738
775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
776		740
777	Sending messages in Erlang is synchronous and blocks the process. AEMP	741	Sending messages in Erlang is synchronous and blocks the process (and
778	sends are immediate, connection establishment is handled in the	742	so does not need a queue that can overflow). AEMP sends are immediate,
779	background.	743	connection establishment is handled in the background.
780		744
781	=item * Erlang can silently lose messages, AEMP cannot.	745	=item * Erlang suffers from silent message loss, AEMP does not.
782		746
783	Erlang makes few guarantees on messages delivery - messages can get lost	747	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,	748	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).	749	and c, and the other side only receives messages a and c).
786		750
787	AEMP guarantees correct ordering, and the guarantee that there are no	751	AEMP guarantees correct ordering, and the guarantee that after one message
788	holes in the message sequence.	752	is lost, all following ones sent to the same port are lost as well, until
789		753	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	754	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		755
801	=item * Erlang can send messages to the wrong port, AEMP does not.	756	=item * Erlang can send messages to the wrong port, AEMP does not.
802		757
803	In Erlang it is quite possible that a node that restarts reuses a process	758	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	759	known to other nodes for a completely different process, causing messages
805	messages destined for that process to end up in an unrelated process.	760	destined for that process to end up in an unrelated process.
806		761
807	AEMP never reuses port IDs, so old messages or old port IDs floating	762	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.	763	around in the network will not be sent to an unrelated port.
809		764
810	=item * Erlang uses unprotected connections, AEMP uses secure	765	=item * Erlang uses unprotected connections, AEMP uses secure
811	authentication and can use TLS.	766	authentication and can use TLS.
812		767
813	AEMP can use a proven protocol - SSL/TLS - to protect connections and	768	AEMP can use a proven protocol - TLS - to protect connections and
814	securely authenticate nodes.	769	securely authenticate nodes.
815		770
816	=item * The AEMP protocol is optimised for both text-based and binary	771	=item * The AEMP protocol is optimised for both text-based and binary
817	communications.	772	communications.
818		773
819	The AEMP protocol, unlike the Erlang protocol, supports both	774	The AEMP protocol, unlike the Erlang protocol, supports both programming
820	language-independent text-only protocols (good for debugging) and binary,	775	language independent text-only protocols (good for debugging) and binary,
821	language-specific serialisers (e.g. Storable).	776	language-specific serialisers (e.g. Storable). By default, unless TLS is
		777	used, the protocol is actually completely text-based.
822		778
823	It has also been carefully designed to be implementable in other languages	779	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	780	with a minimum of work while gracefully degrading functionality to make the
825	protocol simple.	781	protocol simple.
826		782
827	=item * AEMP has more flexible monitoring options than Erlang.	783	=item * AEMP has more flexible monitoring options than Erlang.
828		784
829	In Erlang, you can chose to receive I<all> exit signals as messages	785	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	788	Erlang, as one can choose between automatic kill, exit message or callback
833	on a per-process basis.	789	on a per-process basis.
834		790
835	=item * Erlang tries to hide remote/local connections, AEMP does not.	791	=item * Erlang tries to hide remote/local connections, AEMP does not.
836		792
837	Monitoring in Erlang is not an indicator of process death/crashes,	793	Monitoring in Erlang is not an indicator of process death/crashes, in the
838	as linking is (except linking is unreliable in Erlang).	794	same way as linking is (except linking is unreliable in Erlang).
839		795
840	In AEMP, you don't "look up" registered port names or send to named ports	796	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	797	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	798	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	799	remote port. Since both monitors are local to the node, they are much more
844	more reliable.	800	reliable (no need for C<spawn_link>).
845		801
846	This also saves round-trips and avoids sending messages to the wrong port	802	This also saves round-trips and avoids sending messages to the wrong port
847	(hard to do in Erlang).	803	(hard to do in Erlang).
848		804
849	=back	805	=back
850		806
		807	=head1 RATIONALE
		808
		809	=over 4
		810
		811	=item Why strings for port and node IDs, why not objects?
		812
		813	We considered "objects", but found that the actual number of methods
		814	that can be called are quite low. Since port and node IDs travel over
		815	the network frequently, the serialising/deserialising would add lots of
		816	overhead, as well as having to keep a proxy object everywhere.
		817
		818	Strings can easily be printed, easily serialised etc. and need no special
		819	procedures to be "valid".
		820
		821	And as a result, a miniport consists of a single closure stored in a
		822	global hash - it can't become much cheaper.
		823
		824	=item Why favour JSON, why not a real serialising format such as Storable?
		825
		826	In fact, any AnyEvent::MP node will happily accept Storable as framing
		827	format, but currently there is no way to make a node use Storable by
		828	default (although all nodes will accept it).
		829
		830	The default framing protocol is JSON because a) JSON::XS is many times
		831	faster for small messages and b) most importantly, after years of
		832	experience we found that object serialisation is causing more problems
		833	than it solves: Just like function calls, objects simply do not travel
		834	easily over the network, mostly because they will always be a copy, so you
		835	always have to re-think your design.
		836
		837	Keeping your messages simple, concentrating on data structures rather than
		838	objects, will keep your messages clean, tidy and efficient.
		839
		840	=back
		841
851	=head1 SEE ALSO	842	=head1 SEE ALSO
		843
		844	L<AnyEvent::MP::Intro> - a gentle introduction.
		845
		846	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		847
		848	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		849	your applications.
852		850
853	L<AnyEvent>.	851	L<AnyEvent>.
854		852
855	=head1 AUTHOR	853	=head1 AUTHOR
856		854

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs. Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC