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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.40 by root, Sat Aug 8 00:22:16 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 = '0.1';	136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		137
121	our @EXPORT = qw(	138	our @EXPORT = qw(
122	NODE $NODE *SELF node_of _any_	139	NODE $NODE *SELF node_of after
123	resolve_node initialise_node	140	configure
124	snd rcv mon kil reg psub spawn	141	snd rcv mon mon_guard kil reg psub spawn
125	port	142	port
126	);	143	);
127		144
128	our $SELF;	145	our $SELF;
129		146
…		…
133	kil $SELF, die => $msg;	150	kil $SELF, die => $msg;
134	}	151	}
135		152
136	=item $thisnode = NODE / $NODE	153	=item $thisnode = NODE / $NODE
137		154
138	The C<NODE> function returns, and the C<$NODE> variable contains	155	The C<NODE> function returns, and the C<$NODE> variable contains, the node
139	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
140	to C<become_public> or C<become_slave>, after which all local port	157	a call to C<configure>.
141	identifiers become invalid.
142		158
143	=item $noderef = node_of $port	159	=item $nodeid = node_of $port
144		160
145	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.
146		162
147	=item initialise_node $noderef, $seednode, $seednode...	163	=item configure $profile, key => value...
148		164
149	=item initialise_node "slave/", $master, $master...	165	=item configure key => value...
150		166
151	Before a node can talk to other nodes on the network it has to initialise	167	Before a node can talk to other nodes on the network (i.e. enter
152	itself - the minimum a node needs to know is it's own name, and optionally	168	"distributed mode") it has to configure itself - the minimum a node needs
153	it should know the noderefs of some other nodes in the network.	169	to know is its own name, and optionally it should know the addresses of
		170	some other nodes in the network to discover other nodes.
154		171
155	This function initialises a node - it must be called exactly once (or	172	This function configures a node - it must be called exactly once (or
156	never) before calling other AnyEvent::MP functions.	173	never) before calling other AnyEvent::MP functions.
157		174
158	All arguments are noderefs, which can be either resolved or unresolved.
159
160	There are two types of networked nodes, public nodes and slave nodes:
161
162	=over 4	175	=over 4
163		176
164	=item public nodes	177	=item step 1, gathering configuration from profiles
165		178
166	For public nodes, C<$noderef> must either be a (possibly unresolved)	179	The function first looks up a profile in the aemp configuration (see the
167	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
168	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.
169		183
170	Afterwards, the node will bind itself on all endpoints and try to connect	184	The profile data is then gathered as follows:
171	to all additional C<$seednodes> that are specified. Seednodes are optional
172	and can be used to quickly bootstrap the node into an existing network.
173		185
174	=item slave nodes	186	First, all remaining key => value pairs (all of which are conveniently
		187	undocumented at the moment) will be interpreted as configuration
		188	data. Then they will be overwritten by any values specified in the global
		189	default configuration (see the F<aemp> utility), then the chain of
		190	profiles chosen by the profile name (and any C<parent> attributes).
175		191
176	When the C<$noderef> is the special string C<slave/>, then the node will	192	That means that the values specified in the profile have highest priority
177	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,
178	route most of their traffic to the master node that they attach to.	194	and can only be used to specify defaults.
179		195
180	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
181	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
182	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.
183		217
184	=back	218	=back
185		219
186	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.
187	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.
188	server.
189		222
190	Example: become a public node listening on the default node.	223	configure
191		224
192	initialise_node;	225	Example: become an anonymous node. This form is often used for commandline
		226	clients.
193		227
194	Example: become a public node, and try to contact some well-known master	228	configure nodeid => "anon/";
195	servers to become part of the network.
196		229
197	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).
198		233
199	Example: become a public node listening on port C<4041>.	234	# use the aemp commandline utility
		235	# aemp profile seed nodeid anon/ binds '*:4040'
200		236
201	initialise_node 4041;	237	# then use it
		238	configure profile => "seed";
202		239
203	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
204		242
205	initialise_node "locahost:4044";	243	# or provide a nicer-to-remember nodeid
206		244	# aemp run profile seed nodeid "$(hostname)"
207	Example: become a slave node to any of the specified master servers.
208
209	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
210
211	=item $cv = resolve_node $noderef
212
213	Takes an unresolved node reference that may contain hostnames and
214	abbreviated IDs, resolves all of them and returns a resolved node
215	reference.
216
217	In addition to C<address:port> pairs allowed in resolved noderefs, the
218	following forms are supported:
219
220	=over 4
221
222	=item the empty string
223
224	An empty-string component gets resolved as if the default port (4040) was
225	specified.
226
227	=item naked port numbers (e.g. C<1234>)
228
229	These are resolved by prepending the local nodename and a colon, to be
230	further resolved.
231
232	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
233
234	These are resolved by using AnyEvent::DNS to resolve them, optionally
235	looking up SRV records for the C<aemp=4040> port, if no port was
236	specified.
237
238	=back
239		245
240	=item $SELF	246	=item $SELF
241		247
242	Contains the current port id while executing C<rcv> callbacks or C<psub>	248	Contains the current port id while executing C<rcv> callbacks or C<psub>
243	blocks.	249	blocks.
244		250
245	=item SELF, %SELF, @SELF...	251	=item *SELF, SELF, %SELF, @SELF...
246		252
247	Due to some quirks in how perl exports variables, it is impossible to	253	Due to some quirks in how perl exports variables, it is impossible to
248	just export C<$SELF>, all the symbols called C<SELF> are exported by this	254	just export C<$SELF>, all the symbols named C<SELF> are exported by this
249	module, but only C<$SELF> is currently used.	255	module, but only C<$SELF> is currently used.
250		256
251	=item snd $port, type => @data	257	=item snd $port, type => @data
252		258
253	=item snd $port, @msg	259	=item snd $port, @msg
254		260
255	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
256	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.
257	stringifies a sa port ID (such as a port object :).
258		263
259	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
260	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
261	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.
262		268
263	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
264	function: modifying any argument is not allowed and can cause many	270	function: modifying any argument (or values referenced by them) is
265	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.
266		275
267	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
268	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
269	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
270	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
271	node, anything can be passed.	280	node, anything can be passed. Best rely only on the common denominator of
		281	these.
272		282
273	=item $local_port = port	283	=item $local_port = port
274		284
275	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
276	matching port ("full port") or a single-callback port ("miniport"),	286	no callbacks set and will throw an error when it receives messages.
277	depending on how C<rcv> callbacks are bound to the object.
278		287
279	=item $port = port { my @msg = @_; $finished }	288	=item $local_port = port { my @msg = @_ }
280		289
281	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
282	matching behind it, and returns its ID. Semantically the same as creating
283	a port and calling C<rcv $port, $callback> on it.	291	creating a port and calling C<rcv $port, $callback> on it.
284		292
285	The block will be called for every message received on the port. When the	293	The block will be called for every message received on the port, with the
286	callback returns a true value its job is considered "done" and the port	294	global variable C<$SELF> set to the port ID. Runtime errors will cause the
287	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.
288		297
289	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:
290	be passed to the callback.
291		299
292	If you need the local port id in the callback, this works nicely:	300	my $port = port {
293		301	my @msg = @_;
294	my $port; $port = port {	302	...
295	snd $otherport, reply => $port;	303	kil $SELF;
296	};	304	};
297		305
298	=cut	306	=cut
299		307
300	sub rcv($@);	308	sub rcv($@);
		309
		310	sub _kilme {
		311	die "received message on port without callback";
		312	}
301		313
302	sub port(;&) {	314	sub port(;&) {
303	my $id = "$UNIQ." . $ID++;	315	my $id = "$UNIQ." . $ID++;
304	my $port = "$NODE#$id";	316	my $port = "$NODE#$id";
305		317
306	if (@_) {	318	rcv $port, shift \|\| \&_kilme;
307	rcv $port, shift;
308	} else {
309	$PORT{$id} = sub { }; # nop
310	}
311		319
312	$port	320	$port
313	}	321	}
314		322
315	=item reg $port, $name
316
317	=item reg $name
318
319	Registers the given port (or C<$SELF><<< if missing) under the name
320	C<$name>. If the name already exists it is replaced.
321
322	A port can only be registered under one well known name.
323
324	A port automatically becomes unregistered when it is killed.
325
326	=cut
327
328	sub reg(@) {
329	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
330
331	$REG{$_[0]} = $port;
332	}
333
334	=item rcv $port, $callback->(@msg)	323	=item rcv $local_port, $callback->(@msg)
335		324
336	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
337	one if required).	326	remove the default callback: use C<sub { }> to disable it, or better
338		327	C<kil> the port when it is no longer needed.
339	=item rcv $port, tagstring => $callback->(@msg), ...
340
341	=item rcv $port, $smartmatch => $callback->(@msg), ...
342
343	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
344
345	Register callbacks to be called on matching messages on the given full
346	port (after converting it to one if required) and return the port.
347
348	The callback has to return a true value when its work is done, after
349	which is will be removed, or a false value in which case it will stay
350	registered.
351		328
352	The global C<$SELF> (exported by this module) contains C<$port> while	329	The global C<$SELF> (exported by this module) contains C<$port> while
353	executing the callback.	330	executing the callback. Runtime errors during callback execution will
		331	result in the port being C<kil>ed.
354		332
355	Runtime errors during callback execution will result in the port being	333	The default callback received all messages not matched by a more specific
356	C<kil>ed.	334	C<tag> match.
357		335
358	If the match is an array reference, then it will be matched against the	336	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
359	first elements of the message, otherwise only the first element is being
360	matched.
361		337
362	Any element in the match that is specified as C<_any_> (a function	338	Register (or replace) callbacks to be called on messages starting with the
363	exported by this module) matches any single element of the message.	339	given tag on the given port (and return the port), or unregister it (when
		340	C<$callback> is C<$undef> or missing). There can only be one callback
		341	registered for each tag.
364		342
365	While not required, it is highly recommended that the first matching	343	The original message will be passed to the callback, after the first
366	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
367	also the most efficient match (by far).	345	environment as the default callback (see above).
368		346
369	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.
370		348
371	my $port = rcv port,	349	my $port = rcv port,
372	msg1 => sub { ...; 0 },	350	msg1 => sub { ... },
373	msg2 => sub { ...; 0 },	351	msg2 => sub { ... },
374	;	352	;
375		353
376	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
377	in one go:	355	in one go:
378		356
379	snd $otherport, reply =>	357	snd $otherport, reply =>
380	rcv port,	358	rcv port,
381	msg1 => sub { ...; 0 },	359	msg1 => sub { ... },
382	...	360	...
383	;	361	;
384		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, $otherport;
		370	};
		371
385	=cut	372	=cut
386		373
387	sub rcv($@) {	374	sub rcv($@) {
388	my $port = shift;	375	my $port = shift;
389	my ($noderef, $portid) = split /#/, $port, 2;	376	my ($nodeid, $portid) = split /#/, $port, 2;
390		377
391	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	378	$NODE{$nodeid} == $NODE{""}
392	or Carp::croak "$port: rcv can only be called on local ports, caught";	379	or Carp::croak "$port: rcv can only be called on local ports, caught";
393		380
394	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 {
395	my $cb = shift;	389	my $cb = shift;
396	delete $PORT_DATA{$portid};
397	$PORT{$portid} = sub {	390	$PORT{$portid} = sub {
398	local $SELF = $port;	391	local $SELF = $port;
399	eval {	392	eval { &$cb }; _self_die if $@;
400	&$cb	393	};
401	and kil $port;
402	};	394	}
403	_self_die if $@;	395	} elsif (defined $_[0]) {
404	};
405	} else {
406	my $self = $PORT_DATA{$portid} \|\|= do {	396	my $self = $PORT_DATA{$portid} \|\|= do {
407	my $self = bless {	397	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
408	id => $port,
409	}, "AnyEvent::MP::Port";
410		398
411	$PORT{$portid} = sub {	399	$PORT{$portid} = sub {
412	local $SELF = $port;	400	local $SELF = $port;
413		401
414	eval {
415	for (@{ $self->{rc0}{$_[0]} }) {	402	if (my $cb = $self->[1]{$_[0]}) {
416	$_ && &{$_->[0]}	403	shift;
417	&& undef $_;	404	eval { &$cb }; _self_die if $@;
418	}	405	} else {
419
420	for (@{ $self->{rcv}{$_[0]} }) {
421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
422	&& &{$_->[0]}	406	&{ $self->[0] };
423	&& undef $_;
424	}
425
426	for (@{ $self->{any} }) {
427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
428	&& &{$_->[0]}
429	&& undef $_;
430	}	407	}
431	};	408	};
432	_self_die if $@;	409
		410	$self
433	};	411	};
434		412
435	$self
436	};
437
438	"AnyEvent::MP::Port" eq ref $self	413	"AnyEvent::MP::Port" eq ref $self
439	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
440		415
441	while (@_) {
442	my ($match, $cb) = splice @_, 0, 2;	416	my ($tag, $cb) = splice @_, 0, 2;
443		417
444	if (!ref $match) {	418	if (defined $cb) {
445	push @{ $self->{rc0}{$match} }, [$cb];	419	$self->[1]{$tag} = $cb;
446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
447	my ($type, @match) = @$match;
448	@match
449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
451	} else {	420	} else {
452	push @{ $self->{any} }, [$cb, $match];	421	delete $self->[1]{$tag};
453	}	422	}
454	}	423	}
455	}	424	}
456		425
457	$port	426	$port
…		…
493	$res	462	$res
494	}	463	}
495	}	464	}
496	}	465	}
497		466
498	=item $guard = mon $port, $cb->(@reason)	467	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
499		468
500	=item $guard = mon $port, $rcvport	469	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
501		470
502	=item $guard = mon $port	471	=item $guard = mon $port # kill $SELF when $port dies
503		472
504	=item $guard = mon $port, $rcvport, @msg	473	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
505		474
506	Monitor the given port and do something when the port is killed, and	475	Monitor the given port and do something when the port is killed or
507	optionally return a guard that can be used to stop monitoring again.	476	messages to it were lost, and optionally return a guard that can be used
		477	to stop monitoring again.
		478
		479	C<mon> effectively guarantees that, in the absence of hardware failures,
		480	after starting the monitor, either all messages sent to the port will
		481	arrive, or the monitoring action will be invoked after possible message
		482	loss has been detected. No messages will be lost "in between" (after
		483	the first lost message no further messages will be received by the
		484	port). After the monitoring action was invoked, further messages might get
		485	delivered again.
		486
		487	Note that monitoring-actions are one-shot: once messages are lost (and a
		488	monitoring alert was raised), they are removed and will not trigger again.
508		489
509	In the first form (callback), the callback is simply called with any	490	In the first form (callback), the callback is simply called with any
510	number of C<@reason> elements (no @reason means that the port was deleted	491	number of C<@reason> elements (no @reason means that the port was deleted
511	"normally"). Note also that I<< the callback B<must> never die >>, so use	492	"normally"). Note also that I<< the callback B<must> never die >>, so use
512	C<eval> if unsure.	493	C<eval> if unsure.
513		494
514	In the second form (another port given), the other port (C<$rcvport)	495	In the second form (another port given), the other port (C<$rcvport>)
515	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	496	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
516	"normal" kils nothing happens, while under all other conditions, the other	497	"normal" kils nothing happens, while under all other conditions, the other
517	port is killed with the same reason.	498	port is killed with the same reason.
518		499
519	The third form (kill self) is the same as the second form, except that	500	The third form (kill self) is the same as the second form, except that
520	C<$rvport> defaults to C<$SELF>.	501	C<$rvport> defaults to C<$SELF>.
…		…
523	C<snd>.	504	C<snd>.
524		505
525	As a rule of thumb, monitoring requests should always monitor a port from	506	As a rule of thumb, monitoring requests should always monitor a port from
526	a local port (or callback). The reason is that kill messages might get	507	a local port (or callback). The reason is that kill messages might get
527	lost, just like any other message. Another less obvious reason is that	508	lost, just like any other message. Another less obvious reason is that
528	even monitoring requests can get lost (for exmaple, when the connection	509	even monitoring requests can get lost (for example, when the connection
529	to the other node goes down permanently). When monitoring a port locally	510	to the other node goes down permanently). When monitoring a port locally
530	these problems do not exist.	511	these problems do not exist.
531		512
532	Example: call a given callback when C<$port> is killed.	513	Example: call a given callback when C<$port> is killed.
533		514
…		…
542	mon $port, $self => "restart";	523	mon $port, $self => "restart";
543		524
544	=cut	525	=cut
545		526
546	sub mon {	527	sub mon {
547	my ($noderef, $port) = split /#/, shift, 2;	528	my ($nodeid, $port) = split /#/, shift, 2;
548		529
549	my $node = $NODE{$noderef} \|\| add_node $noderef;	530	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
550		531
551	my $cb = @_ ? $_[0] : $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,';
552		533
553	unless (ref $cb) {	534	unless (ref $cb) {
554	if (@_) {	535	if (@_) {
555	# send a kill info message	536	# send a kill info message
556	my (@msg) = @_;	537	my (@msg) = ($cb, @_);
557	$cb = sub { snd @msg, @_ };	538	$cb = sub { snd @msg, @_ };
558	} else {	539	} else {
559	# simply kill other port	540	# simply kill other port
560	my $port = $cb;	541	my $port = $cb;
561	$cb = sub { kil $port, @_ if @_ };	542	$cb = sub { kil $port, @_ if @_ };
…		…
574	is killed, the references will be freed.	555	is killed, the references will be freed.
575		556
576	Optionally returns a guard that will stop the monitoring.	557	Optionally returns a guard that will stop the monitoring.
577		558
578	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
579	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>):
580		561
581	$port->rcv (start => sub {	562	$port->rcv (start => sub {
582	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	563	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
583	undef $timer if 0.9 < rand;	564	undef $timer if 0.9 < rand;
584	});	565	});
585	});	566	});
586		567
587	=cut	568	=cut
…		…
596		577
597	=item kil $port[, @reason]	578	=item kil $port[, @reason]
598		579
599	Kill the specified port with the given C<@reason>.	580	Kill the specified port with the given C<@reason>.
600		581
601	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
602	ports will not be kileld, or even notified).	583	monitoring other ports will not necessarily die because a port dies
		584	"normally").
603		585
604	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
605	C<mon>, see below).	587	C<mon>, see above).
606		588
607	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
608	will be reported as reason C<< die => $@ >>.	590	will be reported as reason C<< die => $@ >>.
609		591
610	Transport/communication errors are reported as C<< transport_error =>	592	Transport/communication errors are reported as C<< transport_error =>
…		…
615	=item $port = spawn $node, $initfunc[, @initdata]	597	=item $port = spawn $node, $initfunc[, @initdata]
616		598
617	Creates a port on the node C<$node> (which can also be a port ID, in which	599	Creates a port on the node C<$node> (which can also be a port ID, in which
618	case it's the node where that port resides).	600	case it's the node where that port resides).
619		601
620	The port ID of the newly created port is return immediately, and it is	602	The port ID of the newly created port is returned immediately, and it is
621	permissible to immediately start sending messages or monitor the port.	603	possible to immediately start sending messages or to monitor the port.
622		604
623	After the port has been created, the init function is	605	After the port has been created, the init function is called on the remote
624	called. This function must be a fully-qualified function name	606	node, in the same context as a C<rcv> callback. This function must be a
625	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	607	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
626	program, use C<::name>.	608	specify a function in the main program, use C<::name>.
627		609
628	If the function doesn't exist, then the node tries to C<require>	610	If the function doesn't exist, then the node tries to C<require>
629	the package, then the package above the package and so on (e.g.	611	the package, then the package above the package and so on (e.g.
630	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	612	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
631	exists or it runs out of package names.	613	exists or it runs out of package names.
632		614
633	The init function is then called with the newly-created port as context	615	The init function is then called with the newly-created port as context
634	object (C<$SELF>) and the C<@initdata> values as arguments.	616	object (C<$SELF>) and the C<@initdata> values as arguments.
635		617
636	A common idiom is to pass your own port, monitor the spawned port, and	618	A common idiom is to pass a local port, immediately monitor the spawned
637	in the init function, monitor the original port. This two-way monitoring	619	port, and in the remote init function, immediately monitor the passed
638	ensures that both ports get cleaned up when there is a problem.	620	local port. This two-way monitoring ensures that both ports get cleaned up
		621	when there is a problem.
639		622
640	Example: spawn a chat server port on C<$othernode>.	623	Example: spawn a chat server port on C<$othernode>.
641		624
642	# this node, executed from within a port context:	625	# this node, executed from within a port context:
643	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	626	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
666	};	649	};
667	_self_die if $@;	650	_self_die if $@;
668	}	651	}
669		652
670	sub spawn(@) {	653	sub spawn(@) {
671	my ($noderef, undef) = split /#/, shift, 2;	654	my ($nodeid, undef) = split /#/, shift, 2;
672		655
673	my $id = "$RUNIQ." . $ID++;	656	my $id = "$RUNIQ." . $ID++;
674		657
675	$_[0] =~ /::/	658	$_[0] =~ /::/
676	or Carp::croak "spawn init function must be a fully-qualified name, caught";	659	or Carp::croak "spawn init function must be a fully-qualified name, caught";
677		660
678	($NODE{$noderef} \|\| add_node $noderef)	661	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
679	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
680		662
681	"$noderef#$id"	663	"$nodeid#$id"
682	}	664	}
683		665
684	=back	666	=item after $timeout, @msg
685		667
686	=head1 NODE MESSAGES	668	=item after $timeout, $callback
687		669
688	Nodes understand the following messages sent to them. Many of them take	670	Either sends the given message, or call the given callback, after the
689	arguments called C<@reply>, which will simply be used to compose a reply	671	specified number of seconds.
690	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
691	the remaining arguments are simply the message data.
692		672
693	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.
694		676
695	=over 4
696
697	=cut	677	=cut
698		678
699	=item lookup => $name, @reply	679	sub after($@) {
		680	my ($timeout, @action) = @_;
700		681
701	Replies with the port ID of the specified well-known port, or C<undef>.	682	my $t; $t = AE::timer $timeout, 0, sub {
702		683	undef $t;
703	=item devnull => ...	684	ref $action[0]
704		685	? $action[0]()
705	Generic data sink/CPU heat conversion.	686	: snd @action;
706		687	};
707	=item relay => $port, @msg	688	}
708
709	Simply forwards the message to the given port.
710
711	=item eval => $string[ @reply]
712
713	Evaluates the given string. If C<@reply> is given, then a message of the
714	form C<@reply, $@, @evalres> is sent.
715
716	Example: crash another node.
717
718	snd $othernode, eval => "exit";
719
720	=item time => @reply
721
722	Replies the the current node time to C<@reply>.
723
724	Example: tell the current node to send the current time to C<$myport> in a
725	C<timereply> message.
726
727	snd $NODE, time => $myport, timereply => 1, 2;
728	# => snd $myport, timereply => 1, 2, <time>
729		689
730	=back	690	=back
731		691
732	=head1 AnyEvent::MP vs. Distributed Erlang	692	=head1 AnyEvent::MP vs. Distributed Erlang
733		693
…		…
743		703
744	Despite the similarities, there are also some important differences:	704	Despite the similarities, there are also some important differences:
745		705
746	=over 4	706	=over 4
747		707
748	=item * Node references contain the recipe on how to contact them.	708	=item * Node IDs are arbitrary strings in AEMP.
749		709
750	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
751	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
752	convenience functionality.	712	configuration or DNS), but will otherwise discover other odes itself.
753		713
754	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
755	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.
756		728
757	=item * Erlang uses processes and a mailbox, AEMP does not queue.	729	=item * Erlang uses processes and a mailbox, AEMP does not queue.
758		730
759	Erlang uses processes that selctively receive messages, and therefore	731	Erlang uses processes that selectively receive messages, and therefore
760	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
761	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.
762		736
763	(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).
764		738
765	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
766		740
767	Sending messages in Erlang is synchronous and blocks the process. AEMP	741	Sending messages in Erlang is synchronous and blocks the process (and
768	sends are immediate, connection establishment is handled in the	742	so does not need a queue that can overflow). AEMP sends are immediate,
769	background.	743	connection establishment is handled in the background.
770		744
771	=item * Erlang can silently lose messages, AEMP cannot.	745	=item * Erlang suffers from silent message loss, AEMP does not.
772		746
773	Erlang makes few guarantees on messages delivery - messages can get lost	747	Erlang makes few guarantees on messages delivery - messages can get lost
774	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,
775	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).
776		750
777	AEMP guarantees correct ordering, and the guarantee that there are no	751	AEMP guarantees correct ordering, and the guarantee that after one message
778	holes in the message sequence.	752	is lost, all following ones sent to the same port are lost as well, until
779		753	monitoring raises an error, so there are no silent "holes" in the message
780	=item * In Erlang, processes can be declared dead and later be found to be	754	sequence.
781	alive.
782
783	In Erlang it can happen that a monitored process is declared dead and
784	linked processes get killed, but later it turns out that the process is
785	still alive - and can receive messages.
786
787	In AEMP, when port monitoring detects a port as dead, then that port will
788	eventually be killed - it cannot happen that a node detects a port as dead
789	and then later sends messages to it, finding it is still alive.
790		755
791	=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.
792		757
793	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
794	ID known to other nodes for a completely different process, causing	759	known to other nodes for a completely different process, causing messages
795	messages destined for that process to end up in an unrelated process.	760	destined for that process to end up in an unrelated process.
796		761
797	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
798	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.
799		764
800	=item * Erlang uses unprotected connections, AEMP uses secure	765	=item * Erlang uses unprotected connections, AEMP uses secure
801	authentication and can use TLS.	766	authentication and can use TLS.
802		767
803	AEMP can use a proven protocol - SSL/TLS - to protect connections and	768	AEMP can use a proven protocol - TLS - to protect connections and
804	securely authenticate nodes.	769	securely authenticate nodes.
805		770
806	=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
807	communications.	772	communications.
808		773
809	The AEMP protocol, unlike the Erlang protocol, supports both	774	The AEMP protocol, unlike the Erlang protocol, supports both programming
810	language-independent text-only protocols (good for debugging) and binary,	775	language independent text-only protocols (good for debugging) and binary,
811	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.
812		778
813	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
814	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
815	protocol simple.	781	protocol simple.
816		782
817	=item * AEMP has more flexible monitoring options than Erlang.	783	=item * AEMP has more flexible monitoring options than Erlang.
818		784
819	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
…		…
822	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
823	on a per-process basis.	789	on a per-process basis.
824		790
825	=item * Erlang tries to hide remote/local connections, AEMP does not.	791	=item * Erlang tries to hide remote/local connections, AEMP does not.
826		792
827	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
828	as linking is (except linking is unreliable in Erlang).	794	same way as linking is (except linking is unreliable in Erlang).
829		795
830	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
831	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
832	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
833	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
834	more reliable.	800	reliable (no need for C<spawn_link>).
835		801
836	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
837	(hard to do in Erlang).	803	(hard to do in Erlang).
838		804
839	=back	805	=back
840		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
841	=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.
842		850
843	L<AnyEvent>.	851	L<AnyEvent>.
844		852
845	=head1 AUTHOR	853	=head1 AUTHOR
846		854

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.40 by root, Sat Aug 8 00:22:16 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 1.40 by root, Sat Aug 8 00:22:16 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC