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

Comparing cvsroot/AnyEvent-MP/MP.pm (file contents):
Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC vs.
Revision 1.81 by root, Mon Sep 7 18:33:44 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
		12	$SELF # receiving/own port id in rcv callbacks
		13
		14	# initialise the node so it can send/receive messages
		15	configure;
		16
		17	# ports are message destinations
		18
		19	# sending messages
13	snd $port, type => data...;	20	snd $port, type => data...;
		21	snd $port, @msg;
		22	snd @msg_with_first_element_being_a_port;
14		23
15	$SELF # receiving/own port id in rcv callbacks	24	# creating/using ports, the simple way
		25	my $simple_port = port { my @msg = @_ };
16		26
17	rcv $port, smartmatch => $cb->($port, @msg);	27	# creating/using ports, tagged message matching
18		28	my $port = port;
19	# examples:
20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
21	rcv $port1, pong => sub { warn "pong received\n" };	30	rcv $port, pong => sub { warn "pong received\n" };
22	snd $port2, ping => $port1;
23		31
24	# more, smarter, matches (_any_ is exported by this module)	32	# create a port on another node
25	rcv $port, [child_died => $pid] => sub { ...	33	my $port = spawn $node, $initfunc, @initdata;
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
27		34
28	# monitoring	35	# monitoring
29	mon $port, $cb->(@msg) # callback is invoked on death	36	mon $port, $cb->(@msg) # callback is invoked on death
30	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
31	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
32		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 but incomplete, protocol not yet final.
		47
		48	stay tuned.
		49
33	=head1 DESCRIPTION	50	=head1 DESCRIPTION
34		51
35	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
36		53
37	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
38	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
39		56
40	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>
41	manual page.	58	manual page and the examples under F<eg/>.
42
43	At the moment, this module family is severly broken and underdocumented,
44	so do not use. This was uploaded mainly to reserve the CPAN namespace -
45	stay tuned! The basic API should be finished, however.
46		59
47	=head1 CONCEPTS	60	=head1 CONCEPTS
48		61
49	=over 4	62	=over 4
50		63
51	=item port	64	=item port
52		65
53	A port is something you can send messages to (with the C<snd> function).	66	Not to be confused with a TCP port, a "port" is something you can send
		67	messages to (with the C<snd> function).
54		68
55	Some ports allow you to register C<rcv> handlers that can match specific	69	Ports allow you to register C<rcv> handlers that can match all or just
56	messages. All C<rcv> handlers will receive messages they match, messages	70	some messages. Messages send to ports will not be queued, regardless of
57	will not be queued.	71	anything was listening for them or not.
58		72
59	=item port id - C<noderef#portname>	73	=item port ID - C<nodeid#portname>
60		74
61	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	75	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
62	separator, and a port name (a printable string of unspecified format). An	76	separator, and a port name (a printable string of unspecified format).
63	exception is the the node port, whose ID is identical to its node
64	reference.
65		77
66	=item node	78	=item node
67		79
68	A node is a single process containing at least one port - the node	80	A node is a single process containing at least one port - the node port,
69	port. You can send messages to node ports to find existing ports or to	81	which enables nodes to manage each other remotely, and to create new
70	create new ports, among other things.	82	ports.
71		83
72	Nodes are either private (single-process only), slaves (connected to a	84	Nodes are either public (have one or more listening ports) or private
73	master node only) or public nodes (connectable from unrelated nodes).	85	(no listening ports). Private nodes cannot talk to other private nodes
		86	currently.
74		87
75	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	88	=item node ID - C<[a-za-Z0-9_\-.:]+>
76		89
77	A node reference is a string that either simply identifies the node (for	90	A node ID is a string that uniquely identifies the node within a
78	private and slave nodes), or contains a recipe on how to reach a given	91	network. Depending on the configuration used, node IDs can look like a
79	node (for public nodes).	92	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		93	doesn't interpret node IDs in any way.
80		94
81	This recipe is simply a comma-separated list of C<address:port> pairs (for	95	=item binds - C<ip:port>
82	TCP/IP, other protocols might look different).
83		96
84	Node references come in two flavours: resolved (containing only numerical	97	Nodes can only talk to each other by creating some kind of connection to
85	addresses) or unresolved (where hostnames are used instead of addresses).	98	each other. To do this, nodes should listen on one or more local transport
		99	endpoints - binds. Currently, only standard C<ip:port> specifications can
		100	be used, which specify TCP ports to listen on.
86		101
87	Before using an unresolved node reference in a message you first have to	102	=item seeds - C<host:port>
88	resolve it.	103
		104	When a node starts, it knows nothing about the network. To teach the node
		105	about the network it first has to contact some other node within the
		106	network. This node is called a seed.
		107
		108	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		109	are expected to be long-running, and at least one of those should always
		110	be available. When nodes run out of connections (e.g. due to a network
		111	error), they try to re-establish connections to some seednodes again to
		112	join the network.
		113
		114	Apart from being sued for seeding, seednodes are not special in any way -
		115	every public node can be a seednode.
89		116
90	=back	117	=back
91		118
92	=head1 VARIABLES/FUNCTIONS	119	=head1 VARIABLES/FUNCTIONS
93		120
…		…
95		122
96	=cut	123	=cut
97		124
98	package AnyEvent::MP;	125	package AnyEvent::MP;
99		126
100	use AnyEvent::MP::Base;	127	use AnyEvent::MP::Kernel;
101		128
102	use common::sense;	129	use common::sense;
103		130
104	use Carp ();	131	use Carp ();
105		132
106	use AE ();	133	use AE ();
107		134
108	use base "Exporter";	135	use base "Exporter";
109		136
110	our $VERSION = '0.1';	137	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		138
111	our @EXPORT = qw(	139	our @EXPORT = qw(
112	NODE $NODE *SELF node_of _any_	140	NODE $NODE *SELF node_of after
113	resolve_node initialise_node	141	configure
114	snd rcv mon kil reg psub	142	snd rcv mon mon_guard kil reg psub spawn
115	port	143	port
116	);	144	);
117		145
118	our $SELF;	146	our $SELF;
119		147
…		…
123	kil $SELF, die => $msg;	151	kil $SELF, die => $msg;
124	}	152	}
125		153
126	=item $thisnode = NODE / $NODE	154	=item $thisnode = NODE / $NODE
127		155
128	The C<NODE> function returns, and the C<$NODE> variable contains	156	The C<NODE> function returns, and the C<$NODE> variable contains, the node
129	the noderef of the local node. The value is initialised by a call	157	ID of the node running in the current process. This value is initialised by
130	to C<become_public> or C<become_slave>, after which all local port	158	a call to C<configure>.
131	identifiers become invalid.
132		159
133	=item $noderef = node_of $port	160	=item $nodeid = node_of $port
134		161
135	Extracts and returns the noderef from a portid or a noderef.	162	Extracts and returns the node ID from a port ID or a node ID.
136		163
137	=item initialise_node $noderef, $seednode, $seednode...	164	=item configure $profile, key => value...
138		165
139	=item initialise_node "slave/", $master, $master...	166	=item configure key => value...
140		167
141	Before a node can talk to other nodes on the network it has to initialise	168	Before a node can talk to other nodes on the network (i.e. enter
142	itself - the minimum a node needs to know is it's own name, and optionally	169	"distributed mode") it has to configure itself - the minimum a node needs
143	it should know the noderefs of some other nodes in the network.	170	to know is its own name, and optionally it should know the addresses of
		171	some other nodes in the network to discover other nodes.
144		172
145	This function initialises a node - it must be called exactly once (or	173	This function configures a node - it must be called exactly once (or
146	never) before calling other AnyEvent::MP functions.	174	never) before calling other AnyEvent::MP functions.
147		175
148	All arguments are noderefs, which can be either resolved or unresolved.
149
150	There are two types of networked nodes, public nodes and slave nodes:
151
152	=over 4	176	=over 4
153		177
154	=item public nodes	178	=item step 1, gathering configuration from profiles
155		179
156	For public nodes, C<$noderef> must either be a (possibly unresolved)	180	The function first looks up a profile in the aemp configuration (see the
157	noderef, in which case it will be resolved, or C<undef> (or missing), in	181	L<aemp> commandline utility). The profile name can be specified via the
158	which case the noderef will be guessed.	182	named C<profile> parameter or can simply be the first parameter). If it is
		183	missing, then the nodename (F<uname -n>) will be used as profile name.
159		184
160	Afterwards, the node will bind itself on all endpoints and try to connect	185	The profile data is then gathered as follows:
161	to all additional C<$seednodes> that are specified. Seednodes are optional
162	and can be used to quickly bootstrap the node into an existing network.
163		186
164	=item slave nodes	187	First, all remaining key => value pairs (all of which are conveniently
		188	undocumented at the moment) will be interpreted as configuration
		189	data. Then they will be overwritten by any values specified in the global
		190	default configuration (see the F<aemp> utility), then the chain of
		191	profiles chosen by the profile name (and any C<parent> attributes).
165		192
166	When the C<$noderef> is the special string C<slave/>, then the node will	193	That means that the values specified in the profile have highest priority
167	become a slave node. Slave nodes cannot be contacted from outside and will	194	and the values specified directly via C<configure> have lowest priority,
168	route most of their traffic to the master node that they attach to.	195	and can only be used to specify defaults.
169		196
170	At least one additional noderef is required: The node will try to connect	197	If the profile specifies a node ID, then this will become the node ID of
171	to all of them and will become a slave attached to the first node it can	198	this process. If not, then the profile name will be used as node ID. The
172	successfully connect to.	199	special node ID of C<anon/> will be replaced by a random node ID.
		200
		201	=item step 2, bind listener sockets
		202
		203	The next step is to look up the binds in the profile, followed by binding
		204	aemp protocol listeners on all binds specified (it is possible and valid
		205	to have no binds, meaning that the node cannot be contacted form the
		206	outside. This means the node cannot talk to other nodes that also have no
		207	binds, but it can still talk to all "normal" nodes).
		208
		209	If the profile does not specify a binds list, then a default of C<*> is
		210	used, meaning the node will bind on a dynamically-assigned port on every
		211	local IP address it finds.
		212
		213	=item step 3, connect to seed nodes
		214
		215	As the last step, the seeds list from the profile is passed to the
		216	L<AnyEvent::MP::Global> module, which will then use it to keep
		217	connectivity with at least one node at any point in time.
173		218
174	=back	219	=back
175		220
176	This function will block until all nodes have been resolved and, for slave	221	Example: become a distributed node using the locla node name as profile.
177	nodes, until it has successfully established a connection to a master	222	This should be the most common form of invocation for "daemon"-type nodes.
178	server.
179		223
180	Example: become a public node listening on the default node.	224	configure
181		225
182	initialise_node;	226	Example: become an anonymous node. This form is often used for commandline
		227	clients.
183		228
184	Example: become a public node, and try to contact some well-known master	229	configure nodeid => "anon/";
185	servers to become part of the network.
186		230
187	initialise_node undef, "master1", "master2";	231	Example: configure a node using a profile called seed, which si suitable
		232	for a seed node as it binds on all local addresses on a fixed port (4040,
		233	customary for aemp).
188		234
189	Example: become a public node listening on port C<4041>.	235	# use the aemp commandline utility
		236	# aemp profile seed nodeid anon/ binds '*:4040'
190		237
191	initialise_node 4041;	238	# then use it
		239	configure profile => "seed";
192		240
193	Example: become a public node, only visible on localhost port 4044.	241	# or simply use aemp from the shell again:
		242	# aemp run profile seed
194		243
195	initialise_node "locahost:4044";	244	# or provide a nicer-to-remember nodeid
196		245	# aemp run profile seed nodeid "$(hostname)"
197	Example: become a slave node to any of the specified master servers.
198
199	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
200
201	=item $cv = resolve_node $noderef
202
203	Takes an unresolved node reference that may contain hostnames and
204	abbreviated IDs, resolves all of them and returns a resolved node
205	reference.
206
207	In addition to C<address:port> pairs allowed in resolved noderefs, the
208	following forms are supported:
209
210	=over 4
211
212	=item the empty string
213
214	An empty-string component gets resolved as if the default port (4040) was
215	specified.
216
217	=item naked port numbers (e.g. C<1234>)
218
219	These are resolved by prepending the local nodename and a colon, to be
220	further resolved.
221
222	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
223
224	These are resolved by using AnyEvent::DNS to resolve them, optionally
225	looking up SRV records for the C<aemp=4040> port, if no port was
226	specified.
227
228	=back
229		246
230	=item $SELF	247	=item $SELF
231		248
232	Contains the current port id while executing C<rcv> callbacks or C<psub>	249	Contains the current port id while executing C<rcv> callbacks or C<psub>
233	blocks.	250	blocks.
234		251
235	=item SELF, %SELF, @SELF...	252	=item *SELF, SELF, %SELF, @SELF...
236		253
237	Due to some quirks in how perl exports variables, it is impossible to	254	Due to some quirks in how perl exports variables, it is impossible to
238	just export C<$SELF>, all the symbols called C<SELF> are exported by this	255	just export C<$SELF>, all the symbols named C<SELF> are exported by this
239	module, but only C<$SELF> is currently used.	256	module, but only C<$SELF> is currently used.
240		257
241	=item snd $port, type => @data	258	=item snd $port, type => @data
242		259
243	=item snd $port, @msg	260	=item snd $port, @msg
244		261
245	Send the given message to the given port ID, which can identify either	262	Send the given message to the given port, which can identify either a
246	a local or a remote port, and can be either a string or soemthignt hat	263	local or a remote port, and must be a port ID.
247	stringifies a sa port ID (such as a port object :).
248		264
249	While the message can be about anything, it is highly recommended to use a	265	While the message can be almost anything, it is highly recommended to
250	string as first element (a portid, or some word that indicates a request	266	use a string as first element (a port ID, or some word that indicates a
251	type etc.).	267	request type etc.) and to consist if only simple perl values (scalars,
		268	arrays, hashes) - if you think you need to pass an object, think again.
252		269
253	The message data effectively becomes read-only after a call to this	270	The message data logically becomes read-only after a call to this
254	function: modifying any argument is not allowed and can cause many	271	function: modifying any argument (or values referenced by them) is
255	problems.	272	forbidden, as there can be considerable time between the call to C<snd>
		273	and the time the message is actually being serialised - in fact, it might
		274	never be copied as within the same process it is simply handed to the
		275	receiving port.
256		276
257	The type of data you can transfer depends on the transport protocol: when	277	The type of data you can transfer depends on the transport protocol: when
258	JSON is used, then only strings, numbers and arrays and hashes consisting	278	JSON is used, then only strings, numbers and arrays and hashes consisting
259	of those are allowed (no objects). When Storable is used, then anything	279	of those are allowed (no objects). When Storable is used, then anything
260	that Storable can serialise and deserialise is allowed, and for the local	280	that Storable can serialise and deserialise is allowed, and for the local
261	node, anything can be passed.	281	node, anything can be passed. Best rely only on the common denominator of
		282	these.
262		283
263	=item $local_port = port	284	=item $local_port = port
264		285
265	Create a new local port object that can be used either as a pattern	286	Create a new local port object and returns its port ID. Initially it has
266	matching port ("full port") or a single-callback port ("miniport"),	287	no callbacks set and will throw an error when it receives messages.
267	depending on how C<rcv> callbacks are bound to the object.
268		288
269	=item $port = port { my @msg = @_; $finished }	289	=item $local_port = port { my @msg = @_ }
270		290
271	Creates a "miniport", that is, a very lightweight port without any pattern	291	Creates a new local port, and returns its ID. Semantically the same as
272	matching behind it, and returns its ID. Semantically the same as creating
273	a port and calling C<rcv $port, $callback> on it.	292	creating a port and calling C<rcv $port, $callback> on it.
274		293
275	The block will be called for every message received on the port. When the	294	The block will be called for every message received on the port, with the
276	callback returns a true value its job is considered "done" and the port	295	global variable C<$SELF> set to the port ID. Runtime errors will cause the
277	will be destroyed. Otherwise it will stay alive.	296	port to be C<kil>ed. The message will be passed as-is, no extra argument
		297	(i.e. no port ID) will be passed to the callback.
278		298
279	The message will be passed as-is, no extra argument (i.e. no port id) will	299	If you want to stop/destroy the port, simply C<kil> it:
280	be passed to the callback.
281		300
282	If you need the local port id in the callback, this works nicely:	301	my $port = port {
283		302	my @msg = @_;
284	my $port; $port = port {	303	...
285	snd $otherport, reply => $port;	304	kil $SELF;
286	};	305	};
287		306
288	=cut	307	=cut
289		308
290	sub rcv($@);	309	sub rcv($@);
		310
		311	sub _kilme {
		312	die "received message on port without callback";
		313	}
291		314
292	sub port(;&) {	315	sub port(;&) {
293	my $id = "$UNIQ." . $ID++;	316	my $id = "$UNIQ." . $ID++;
294	my $port = "$NODE#$id";	317	my $port = "$NODE#$id";
295		318
296	if (@_) {	319	rcv $port, shift \|\| \&_kilme;
297	rcv $port, shift;
298	} else {
299	$PORT{$id} = sub { }; # nop
300	}
301		320
302	$port	321	$port
303	}	322	}
304		323
305	=item reg $port, $name
306
307	=item reg $name
308
309	Registers the given port (or C<$SELF><<< if missing) under the name
310	C<$name>. If the name already exists it is replaced.
311
312	A port can only be registered under one well known name.
313
314	A port automatically becomes unregistered when it is killed.
315
316	=cut
317
318	sub reg(@) {
319	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
320
321	$REG{$_[0]} = $port;
322	}
323
324	=item rcv $port, $callback->(@msg)	324	=item rcv $local_port, $callback->(@msg)
325		325
326	Replaces the callback on the specified miniport (after converting it to	326	Replaces the default callback on the specified port. There is no way to
327	one if required).	327	remove the default callback: use C<sub { }> to disable it, or better
328		328	C<kil> the port when it is no longer needed.
329	=item rcv $port, tagstring => $callback->(@msg), ...
330
331	=item rcv $port, $smartmatch => $callback->(@msg), ...
332
333	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
334
335	Register callbacks to be called on matching messages on the given full
336	port (after converting it to one if required) and return the port.
337
338	The callback has to return a true value when its work is done, after
339	which is will be removed, or a false value in which case it will stay
340	registered.
341		329
342	The global C<$SELF> (exported by this module) contains C<$port> while	330	The global C<$SELF> (exported by this module) contains C<$port> while
343	executing the callback.	331	executing the callback. Runtime errors during callback execution will
		332	result in the port being C<kil>ed.
344		333
345	Runtime errors wdurign callback execution will result in the port being	334	The default callback received all messages not matched by a more specific
346	C<kil>ed.	335	C<tag> match.
347		336
348	If the match is an array reference, then it will be matched against the	337	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
349	first elements of the message, otherwise only the first element is being
350	matched.
351		338
352	Any element in the match that is specified as C<_any_> (a function	339	Register (or replace) callbacks to be called on messages starting with the
353	exported by this module) matches any single element of the message.	340	given tag on the given port (and return the port), or unregister it (when
		341	C<$callback> is C<$undef> or missing). There can only be one callback
		342	registered for each tag.
354		343
355	While not required, it is highly recommended that the first matching	344	The original message will be passed to the callback, after the first
356	element is a string identifying the message. The one-string-only match is	345	element (the tag) has been removed. The callback will use the same
357	also the most efficient match (by far).	346	environment as the default callback (see above).
358		347
359	Example: create a port and bind receivers on it in one go.	348	Example: create a port and bind receivers on it in one go.
360		349
361	my $port = rcv port,	350	my $port = rcv port,
362	msg1 => sub { ...; 0 },	351	msg1 => sub { ... },
363	msg2 => sub { ...; 0 },	352	msg2 => sub { ... },
364	;	353	;
365		354
366	Example: create a port, bind receivers and send it in a message elsewhere	355	Example: create a port, bind receivers and send it in a message elsewhere
367	in one go:	356	in one go:
368		357
369	snd $otherport, reply =>	358	snd $otherport, reply =>
370	rcv port,	359	rcv port,
371	msg1 => sub { ...; 0 },	360	msg1 => sub { ... },
372	...	361	...
373	;	362	;
374		363
		364	Example: temporarily register a rcv callback for a tag matching some port
		365	(e.g. for a rpc reply) and unregister it after a message was received.
		366
		367	rcv $port, $otherport => sub {
		368	my @reply = @_;
		369
		370	rcv $SELF, $otherport;
		371	};
		372
375	=cut	373	=cut
376		374
377	sub rcv($@) {	375	sub rcv($@) {
378	my $port = shift;	376	my $port = shift;
379	my ($noderef, $portid) = split /#/, $port, 2;	377	my ($nodeid, $portid) = split /#/, $port, 2;
380		378
381	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	379	$NODE{$nodeid} == $NODE{""}
382	or Carp::croak "$port: rcv can only be called on local ports, caught";	380	or Carp::croak "$port: rcv can only be called on local ports, caught";
383		381
384	if (@_ == 1) {	382	while (@_) {
		383	if (ref $_[0]) {
		384	if (my $self = $PORT_DATA{$portid}) {
		385	"AnyEvent::MP::Port" eq ref $self
		386	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		387
		388	$self->[2] = shift;
		389	} else {
385	my $cb = shift;	390	my $cb = shift;
386	delete $PORT_DATA{$portid};
387	$PORT{$portid} = sub {	391	$PORT{$portid} = sub {
388	local $SELF = $port;	392	local $SELF = $port;
389	eval {	393	eval { &$cb }; _self_die if $@;
390	&$cb	394	};
391	and kil $port;
392	};	395	}
393	_self_die if $@;	396	} elsif (defined $_[0]) {
394	};
395	} else {
396	my $self = $PORT_DATA{$portid} \|\|= do {	397	my $self = $PORT_DATA{$portid} \|\|= do {
397	my $self = bless {	398	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
398	id => $port,
399	}, "AnyEvent::MP::Port";
400		399
401	$PORT{$portid} = sub {	400	$PORT{$portid} = sub {
402	local $SELF = $port;	401	local $SELF = $port;
403		402
404	eval {
405	for (@{ $self->{rc0}{$_[0]} }) {	403	if (my $cb = $self->[1]{$_[0]}) {
406	$_ && &{$_->[0]}	404	shift;
407	&& undef $_;	405	eval { &$cb }; _self_die if $@;
408	}	406	} else {
409
410	for (@{ $self->{rcv}{$_[0]} }) {
411	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
412	&& &{$_->[0]}	407	&{ $self->[0] };
413	&& undef $_;
414	}
415
416	for (@{ $self->{any} }) {
417	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
418	&& &{$_->[0]}
419	&& undef $_;
420	}	408	}
421	};	409	};
422	_self_die if $@;	410
		411	$self
423	};	412	};
424		413
425	$self
426	};
427
428	"AnyEvent::MP::Port" eq ref $self	414	"AnyEvent::MP::Port" eq ref $self
429	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	415	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
430		416
431	while (@_) {
432	my ($match, $cb) = splice @_, 0, 2;	417	my ($tag, $cb) = splice @_, 0, 2;
433		418
434	if (!ref $match) {	419	if (defined $cb) {
435	push @{ $self->{rc0}{$match} }, [$cb];	420	$self->[1]{$tag} = $cb;
436	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
437	my ($type, @match) = @$match;
438	@match
439	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
440	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
441	} else {	421	} else {
442	push @{ $self->{any} }, [$cb, $match];	422	delete $self->[1]{$tag};
443	}	423	}
444	}	424	}
445	}	425	}
446		426
447	$port	427	$port
…		…
483	$res	463	$res
484	}	464	}
485	}	465	}
486	}	466	}
487		467
488	=item $guard = mon $port, $cb->(@reason)	468	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
489		469
490	=item $guard = mon $port, $rcvport	470	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
491		471
492	=item $guard = mon $port	472	=item $guard = mon $port # kill $SELF when $port dies
493		473
494	=item $guard = mon $port, $rcvport, @msg	474	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
495		475
496	Monitor the given port and do something when the port is killed, and	476	Monitor the given port and do something when the port is killed or
497	optionally return a guard that can be used to stop monitoring again.	477	messages to it were lost, and optionally return a guard that can be used
		478	to stop monitoring again.
498		479
499	In the first form (callback), the callback is simply called with any	480	In the first form (callback), the callback is simply called with any
500	number of C<@reason> elements (no @reason means that the port was deleted	481	number of C<@reason> elements (no @reason means that the port was deleted
501	"normally"). Note also that I<< the callback B<must> never die >>, so use	482	"normally"). Note also that I<< the callback B<must> never die >>, so use
502	C<eval> if unsure.	483	C<eval> if unsure.
503		484
504	In the second form (another port given), the other port (C<$rcvport)	485	In the second form (another port given), the other port (C<$rcvport>)
505	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	486	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
506	"normal" kils nothing happens, while under all other conditions, the other	487	"normal" kils nothing happens, while under all other conditions, the other
507	port is killed with the same reason.	488	port is killed with the same reason.
508		489
509	The third form (kill self) is the same as the second form, except that	490	The third form (kill self) is the same as the second form, except that
510	C<$rvport> defaults to C<$SELF>.	491	C<$rvport> defaults to C<$SELF>.
511		492
512	In the last form (message), a message of the form C<@msg, @reason> will be	493	In the last form (message), a message of the form C<@msg, @reason> will be
513	C<snd>.	494	C<snd>.
		495
		496	Monitoring-actions are one-shot: once messages are lost (and a monitoring
		497	alert was raised), they are removed and will not trigger again.
514		498
515	As a rule of thumb, monitoring requests should always monitor a port from	499	As a rule of thumb, monitoring requests should always monitor a port from
516	a local port (or callback). The reason is that kill messages might get	500	a local port (or callback). The reason is that kill messages might get
517	lost, just like any other message. Another less obvious reason is that	501	lost, just like any other message. Another less obvious reason is that
518	even monitoring requests can get lost (for exmaple, when the connection	502	even monitoring requests can get lost (for example, when the connection
519	to the other node goes down permanently). When monitoring a port locally	503	to the other node goes down permanently). When monitoring a port locally
520	these problems do not exist.	504	these problems do not exist.
521		505
		506	C<mon> effectively guarantees that, in the absence of hardware failures,
		507	after starting the monitor, either all messages sent to the port will
		508	arrive, or the monitoring action will be invoked after possible message
		509	loss has been detected. No messages will be lost "in between" (after
		510	the first lost message no further messages will be received by the
		511	port). After the monitoring action was invoked, further messages might get
		512	delivered again.
		513
		514	Inter-host-connection timeouts and monitoring depend on the transport
		515	used. The only transport currently implemented is TCP, and AnyEvent::MP
		516	relies on TCP to detect node-downs (this can take 10-15 minutes on a
		517	non-idle connection, and usually around two hours for idle conenctions).
		518
		519	This means that monitoring is good for program errors and cleaning up
		520	stuff eventually, but they are no replacement for a timeout when you need
		521	to ensure some maximum latency.
		522
522	Example: call a given callback when C<$port> is killed.	523	Example: call a given callback when C<$port> is killed.
523		524
524	mon $port, sub { warn "port died because of <@_>\n" };	525	mon $port, sub { warn "port died because of <@_>\n" };
525		526
526	Example: kill ourselves when C<$port> is killed abnormally.	527	Example: kill ourselves when C<$port> is killed abnormally.
…		…
532	mon $port, $self => "restart";	533	mon $port, $self => "restart";
533		534
534	=cut	535	=cut
535		536
536	sub mon {	537	sub mon {
537	my ($noderef, $port) = split /#/, shift, 2;	538	my ($nodeid, $port) = split /#/, shift, 2;
538		539
539	my $node = $NODE{$noderef} \|\| add_node $noderef;	540	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
540		541
541	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	542	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
542		543
543	unless (ref $cb) {	544	unless (ref $cb) {
544	if (@_) {	545	if (@_) {
545	# send a kill info message	546	# send a kill info message
546	my (@msg) = @_;	547	my (@msg) = ($cb, @_);
547	$cb = sub { snd @msg, @_ };	548	$cb = sub { snd @msg, @_ };
548	} else {	549	} else {
549	# simply kill other port	550	# simply kill other port
550	my $port = $cb;	551	my $port = $cb;
551	$cb = sub { kil $port, @_ if @_ };	552	$cb = sub { kil $port, @_ if @_ };
…		…
564	is killed, the references will be freed.	565	is killed, the references will be freed.
565		566
566	Optionally returns a guard that will stop the monitoring.	567	Optionally returns a guard that will stop the monitoring.
567		568
568	This function is useful when you create e.g. timers or other watchers and	569	This function is useful when you create e.g. timers or other watchers and
569	want to free them when the port gets killed:	570	want to free them when the port gets killed (note the use of C<psub>):
570		571
571	$port->rcv (start => sub {	572	$port->rcv (start => sub {
572	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	573	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
573	undef $timer if 0.9 < rand;	574	undef $timer if 0.9 < rand;
574	});	575	});
575	});	576	});
576		577
577	=cut	578	=cut
…		…
586		587
587	=item kil $port[, @reason]	588	=item kil $port[, @reason]
588		589
589	Kill the specified port with the given C<@reason>.	590	Kill the specified port with the given C<@reason>.
590		591
591	If no C<@reason> is specified, then the port is killed "normally" (linked	592	If no C<@reason> is specified, then the port is killed "normally" (ports
592	ports will not be kileld, or even notified).	593	monitoring other ports will not necessarily die because a port dies
		594	"normally").
593		595
594	Otherwise, linked ports get killed with the same reason (second form of	596	Otherwise, linked ports get killed with the same reason (second form of
595	C<mon>, see below).	597	C<mon>, see above).
596		598
597	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	599	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
598	will be reported as reason C<< die => $@ >>.	600	will be reported as reason C<< die => $@ >>.
599		601
600	Transport/communication errors are reported as C<< transport_error =>	602	Transport/communication errors are reported as C<< transport_error =>
601	$message >>.	603	$message >>.
602		604
603	=back
604
605	=head1 NODE MESSAGES
606
607	Nodes understand the following messages sent to them. Many of them take
608	arguments called C<@reply>, which will simply be used to compose a reply
609	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
610	the remaining arguments are simply the message data.
611
612	While other messages exist, they are not public and subject to change.
613
614	=over 4
615
616	=cut	605	=cut
617		606
618	=item lookup => $name, @reply	607	=item $port = spawn $node, $initfunc[, @initdata]
619		608
620	Replies with the port ID of the specified well-known port, or C<undef>.	609	Creates a port on the node C<$node> (which can also be a port ID, in which
		610	case it's the node where that port resides).
621		611
622	=item devnull => ...	612	The port ID of the newly created port is returned immediately, and it is
		613	possible to immediately start sending messages or to monitor the port.
623		614
624	Generic data sink/CPU heat conversion.	615	After the port has been created, the init function is called on the remote
		616	node, in the same context as a C<rcv> callback. This function must be a
		617	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		618	specify a function in the main program, use C<::name>.
625		619
626	=item relay => $port, @msg	620	If the function doesn't exist, then the node tries to C<require>
		621	the package, then the package above the package and so on (e.g.
		622	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		623	exists or it runs out of package names.
627		624
628	Simply forwards the message to the given port.	625	The init function is then called with the newly-created port as context
		626	object (C<$SELF>) and the C<@initdata> values as arguments.
629		627
630	=item eval => $string[ @reply]	628	A common idiom is to pass a local port, immediately monitor the spawned
		629	port, and in the remote init function, immediately monitor the passed
		630	local port. This two-way monitoring ensures that both ports get cleaned up
		631	when there is a problem.
631		632
632	Evaluates the given string. If C<@reply> is given, then a message of the	633	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
633	form C<@reply, $@, @evalres> is sent.	634	caller before C<spawn> returns (by delaying invocation when spawn is
		635	called for the local node).
634		636
635	Example: crash another node.	637	Example: spawn a chat server port on C<$othernode>.
636		638
637	snd $othernode, eval => "exit";	639	# this node, executed from within a port context:
		640	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		641	mon $server;
638		642
639	=item time => @reply	643	# init function on C<$othernode>
		644	sub connect {
		645	my ($srcport) = @_;
640		646
641	Replies the the current node time to C<@reply>.	647	mon $srcport;
642		648
643	Example: tell the current node to send the current time to C<$myport> in a	649	rcv $SELF, sub {
644	C<timereply> message.	650	...
		651	};
		652	}
645		653
646	snd $NODE, time => $myport, timereply => 1, 2;	654	=cut
647	# => snd $myport, timereply => 1, 2, <time>	655
		656	sub _spawn {
		657	my $port = shift;
		658	my $init = shift;
		659
		660	local $SELF = "$NODE#$port";
		661	eval {
		662	&{ load_func $init }
		663	};
		664	_self_die if $@;
		665	}
		666
		667	sub spawn(@) {
		668	my ($nodeid, undef) = split /#/, shift, 2;
		669
		670	my $id = "$RUNIQ." . $ID++;
		671
		672	$_[0] =~ /::/
		673	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		674
		675	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
		676
		677	"$nodeid#$id"
		678	}
		679
		680	=item after $timeout, @msg
		681
		682	=item after $timeout, $callback
		683
		684	Either sends the given message, or call the given callback, after the
		685	specified number of seconds.
		686
		687	This is simply a utility function that comes in handy at times - the
		688	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		689	so it may go away in the future.
		690
		691	=cut
		692
		693	sub after($@) {
		694	my ($timeout, @action) = @_;
		695
		696	my $t; $t = AE::timer $timeout, 0, sub {
		697	undef $t;
		698	ref $action[0]
		699	? $action[0]()
		700	: snd @action;
		701	};
		702	}
648		703
649	=back	704	=back
650		705
651	=head1 AnyEvent::MP vs. Distributed Erlang	706	=head1 AnyEvent::MP vs. Distributed Erlang
652		707
…		…
662		717
663	Despite the similarities, there are also some important differences:	718	Despite the similarities, there are also some important differences:
664		719
665	=over 4	720	=over 4
666		721
667	=item * Node references contain the recipe on how to contact them.	722	=item * Node IDs are arbitrary strings in AEMP.
668		723
669	Erlang relies on special naming and DNS to work everywhere in the	724	Erlang relies on special naming and DNS to work everywhere in the same
670	same way. AEMP relies on each node knowing it's own address(es), with	725	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
671	convenience functionality.	726	configuration or DNS), but will otherwise discover other odes itself.
672		727
673	This means that AEMP requires a less tightly controlled environment at the	728	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
674	cost of longer node references and a slightly higher management overhead.	729	uses "local ports are like remote ports".
		730
		731	The failure modes for local ports are quite different (runtime errors
		732	only) then for remote ports - when a local port dies, you I<know> it dies,
		733	when a connection to another node dies, you know nothing about the other
		734	port.
		735
		736	Erlang pretends remote ports are as reliable as local ports, even when
		737	they are not.
		738
		739	AEMP encourages a "treat remote ports differently" philosophy, with local
		740	ports being the special case/exception, where transport errors cannot
		741	occur.
675		742
676	=item * Erlang uses processes and a mailbox, AEMP does not queue.	743	=item * Erlang uses processes and a mailbox, AEMP does not queue.
677		744
678	Erlang uses processes that selctively receive messages, and therefore	745	Erlang uses processes that selectively receive messages, and therefore
679	needs a queue. AEMP is event based, queuing messages would serve no useful	746	needs a queue. AEMP is event based, queuing messages would serve no
680	purpose.	747	useful purpose. For the same reason the pattern-matching abilities of
		748	AnyEvent::MP are more limited, as there is little need to be able to
		749	filter messages without dequeuing them.
681		750
682	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	751	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
683		752
684	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	753	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
685		754
686	Sending messages in Erlang is synchronous and blocks the process. AEMP	755	Sending messages in Erlang is synchronous and blocks the process (and
687	sends are immediate, connection establishment is handled in the	756	so does not need a queue that can overflow). AEMP sends are immediate,
688	background.	757	connection establishment is handled in the background.
689		758
690	=item * Erlang can silently lose messages, AEMP cannot.	759	=item * Erlang suffers from silent message loss, AEMP does not.
691		760
692	Erlang makes few guarantees on messages delivery - messages can get lost	761	Erlang makes few guarantees on messages delivery - messages can get lost
693	without any of the processes realising it (i.e. you send messages a, b,	762	without any of the processes realising it (i.e. you send messages a, b,
694	and c, and the other side only receives messages a and c).	763	and c, and the other side only receives messages a and c).
695		764
696	AEMP guarantees correct ordering, and the guarantee that there are no	765	AEMP guarantees correct ordering, and the guarantee that after one message
697	holes in the message sequence.	766	is lost, all following ones sent to the same port are lost as well, until
698		767	monitoring raises an error, so there are no silent "holes" in the message
699	=item * In Erlang, processes can be declared dead and later be found to be	768	sequence.
700	alive.
701
702	In Erlang it can happen that a monitored process is declared dead and
703	linked processes get killed, but later it turns out that the process is
704	still alive - and can receive messages.
705
706	In AEMP, when port monitoring detects a port as dead, then that port will
707	eventually be killed - it cannot happen that a node detects a port as dead
708	and then later sends messages to it, finding it is still alive.
709		769
710	=item * Erlang can send messages to the wrong port, AEMP does not.	770	=item * Erlang can send messages to the wrong port, AEMP does not.
711		771
712	In Erlang it is quite possible that a node that restarts reuses a process	772	In Erlang it is quite likely that a node that restarts reuses a process ID
713	ID known to other nodes for a completely different process, causing	773	known to other nodes for a completely different process, causing messages
714	messages destined for that process to end up in an unrelated process.	774	destined for that process to end up in an unrelated process.
715		775
716	AEMP never reuses port IDs, so old messages or old port IDs floating	776	AEMP never reuses port IDs, so old messages or old port IDs floating
717	around in the network will not be sent to an unrelated port.	777	around in the network will not be sent to an unrelated port.
718		778
719	=item * Erlang uses unprotected connections, AEMP uses secure	779	=item * Erlang uses unprotected connections, AEMP uses secure
720	authentication and can use TLS.	780	authentication and can use TLS.
721		781
722	AEMP can use a proven protocol - SSL/TLS - to protect connections and	782	AEMP can use a proven protocol - TLS - to protect connections and
723	securely authenticate nodes.	783	securely authenticate nodes.
724		784
725	=item * The AEMP protocol is optimised for both text-based and binary	785	=item * The AEMP protocol is optimised for both text-based and binary
726	communications.	786	communications.
727		787
728	The AEMP protocol, unlike the Erlang protocol, supports both	788	The AEMP protocol, unlike the Erlang protocol, supports both programming
729	language-independent text-only protocols (good for debugging) and binary,	789	language independent text-only protocols (good for debugging) and binary,
730	language-specific serialisers (e.g. Storable).	790	language-specific serialisers (e.g. Storable). By default, unless TLS is
		791	used, the protocol is actually completely text-based.
731		792
732	It has also been carefully designed to be implementable in other languages	793	It has also been carefully designed to be implementable in other languages
733	with a minimum of work while gracefully degrading fucntionality to make the	794	with a minimum of work while gracefully degrading functionality to make the
734	protocol simple.	795	protocol simple.
735		796
736	=item * AEMP has more flexible monitoring options than Erlang.	797	=item * AEMP has more flexible monitoring options than Erlang.
737		798
738	In Erlang, you can chose to receive I<all> exit signals as messages	799	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
741	Erlang, as one can choose between automatic kill, exit message or callback	802	Erlang, as one can choose between automatic kill, exit message or callback
742	on a per-process basis.	803	on a per-process basis.
743		804
744	=item * Erlang tries to hide remote/local connections, AEMP does not.	805	=item * Erlang tries to hide remote/local connections, AEMP does not.
745		806
746	Monitoring in Erlang is not an indicator of process death/crashes,	807	Monitoring in Erlang is not an indicator of process death/crashes, in the
747	as linking is (except linking is unreliable in Erlang).	808	same way as linking is (except linking is unreliable in Erlang).
748		809
749	In AEMP, you don't "look up" registered port names or send to named ports	810	In AEMP, you don't "look up" registered port names or send to named ports
750	that might or might not be persistent. Instead, you normally spawn a port	811	that might or might not be persistent. Instead, you normally spawn a port
751	on the remote node. The init function monitors the you, and you monitor	812	on the remote node. The init function monitors you, and you monitor the
752	the remote port. Since both monitors are local to the node, they are much	813	remote port. Since both monitors are local to the node, they are much more
753	more reliable.	814	reliable (no need for C<spawn_link>).
754		815
755	This also saves round-trips and avoids sending messages to the wrong port	816	This also saves round-trips and avoids sending messages to the wrong port
756	(hard to do in Erlang).	817	(hard to do in Erlang).
757		818
758	=back	819	=back
759		820
		821	=head1 RATIONALE
		822
		823	=over 4
		824
		825	=item Why strings for port and node IDs, why not objects?
		826
		827	We considered "objects", but found that the actual number of methods
		828	that can be called are quite low. Since port and node IDs travel over
		829	the network frequently, the serialising/deserialising would add lots of
		830	overhead, as well as having to keep a proxy object everywhere.
		831
		832	Strings can easily be printed, easily serialised etc. and need no special
		833	procedures to be "valid".
		834
		835	And as a result, a miniport consists of a single closure stored in a
		836	global hash - it can't become much cheaper.
		837
		838	=item Why favour JSON, why not a real serialising format such as Storable?
		839
		840	In fact, any AnyEvent::MP node will happily accept Storable as framing
		841	format, but currently there is no way to make a node use Storable by
		842	default (although all nodes will accept it).
		843
		844	The default framing protocol is JSON because a) JSON::XS is many times
		845	faster for small messages and b) most importantly, after years of
		846	experience we found that object serialisation is causing more problems
		847	than it solves: Just like function calls, objects simply do not travel
		848	easily over the network, mostly because they will always be a copy, so you
		849	always have to re-think your design.
		850
		851	Keeping your messages simple, concentrating on data structures rather than
		852	objects, will keep your messages clean, tidy and efficient.
		853
		854	=back
		855
760	=head1 SEE ALSO	856	=head1 SEE ALSO
		857
		858	L<AnyEvent::MP::Intro> - a gentle introduction.
		859
		860	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		861
		862	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		863	your applications.
		864
		865	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from
		866	all nodes.
761		867
762	L<AnyEvent>.	868	L<AnyEvent>.
763		869
764	=head1 AUTHOR	870	=head1 AUTHOR
765		871

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Comparing cvsroot/AnyEvent-MP/MP.pm (file contents): Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC vs. Revision 1.81 by root, Mon Sep 7 18:33:44 2009 UTC

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Comparing cvsroot/AnyEvent-MP/MP.pm (file contents):
Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC vs.
Revision 1.81 by root, Mon Sep 7 18:33:44 2009 UTC