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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC vs.
Revision 1.77 by elmex, Thu Sep 3 07:57:30 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 key => value...
148		164
149	=item initialise_node "slave/", $master, $master...
150
151	Before a node can talk to other nodes on the network it has to initialise	165	Before a node can talk to other nodes on the network (i.e. enter
152	itself - the minimum a node needs to know is it's own name, and optionally	166	"distributed mode") it has to configure itself - the minimum a node needs
153	it should know the noderefs of some other nodes in the network.	167	to know is its own name, and optionally it should know the addresses of
		168	some other nodes in the network to discover other nodes.
154		169
155	This function initialises a node - it must be called exactly once (or	170	This function configures a node - it must be called exactly once (or
156	never) before calling other AnyEvent::MP functions.	171	never) before calling other AnyEvent::MP functions.
157		172
158	All arguments are noderefs, which can be either resolved or unresolved.
159
160	There are two types of networked nodes, public nodes and slave nodes:
161
162	=over 4	173	=over 4
163		174
164	=item public nodes	175	=item step 1, gathering configuration from profiles
165		176
166	For public nodes, C<$noderef> must either be a (possibly unresolved)	177	The function first looks up a profile in the aemp configuration (see the
167	noderef, in which case it will be resolved, or C<undef> (or missing), in	178	L<aemp> commandline utility). The profile name can be specified via the
168	which case the noderef will be guessed.	179	named C<profile> parameter. If it is missing, then the nodename (F<uname
		180	-n>) will be used as profile name.
169		181
170	Afterwards, the node will bind itself on all endpoints and try to connect	182	The profile data is then gathered as follows:
171	to all additional C<$seednodes> that are specified. Seednodes are optional
172	and can be used to quickly bootstrap the node into an existing network.
173		183
174	=item slave nodes	184	First, all remaining key => value pairs (all of which are conveniently
		185	undocumented at the moment) will be interpreted as configuration
		186	data. Then they will be overwritten by any values specified in the global
		187	default configuration (see the F<aemp> utility), then the chain of
		188	profiles chosen by the profile name (and any C<parent> attributes).
175		189
176	When the C<$noderef> is the special string C<slave/>, then the node will	190	That means that the values specified in the profile have highest priority
177	become a slave node. Slave nodes cannot be contacted from outside and will	191	and the values specified directly via C<configure> have lowest priority,
178	route most of their traffic to the master node that they attach to.	192	and can only be used to specify defaults.
179		193
180	At least one additional noderef is required: The node will try to connect	194	If the profile specifies a node ID, then this will become the node ID of
181	to all of them and will become a slave attached to the first node it can	195	this process. If not, then the profile name will be used as node ID. The
182	successfully connect to.	196	special node ID of C<anon/> will be replaced by a random node ID.
		197
		198	=item step 2, bind listener sockets
		199
		200	The next step is to look up the binds in the profile, followed by binding
		201	aemp protocol listeners on all binds specified (it is possible and valid
		202	to have no binds, meaning that the node cannot be contacted form the
		203	outside. This means the node cannot talk to other nodes that also have no
		204	binds, but it can still talk to all "normal" nodes).
		205
		206	If the profile does not specify a binds list, then a default of C<*> is
		207	used, meaning the node will bind on a dynamically-assigned port on every
		208	local IP address it finds.
		209
		210	=item step 3, connect to seed nodes
		211
		212	As the last step, the seeds list from the profile is passed to the
		213	L<AnyEvent::MP::Global> module, which will then use it to keep
		214	connectivity with at least one node at any point in time.
183		215
184	=back	216	=back
185		217
186	This function will block until all nodes have been resolved and, for slave	218	Example: become a distributed node using the locla node name as profile.
187	nodes, until it has successfully established a connection to a master	219	This should be the most common form of invocation for "daemon"-type nodes.
188	server.
189		220
190	Example: become a public node listening on the default node.	221	configure
191		222
192	initialise_node;	223	Example: become an anonymous node. This form is often used for commandline
		224	clients.
193		225
194	Example: become a public node, and try to contact some well-known master	226	configure nodeid => "anon/";
195	servers to become part of the network.
196		227
197	initialise_node undef, "master1", "master2";	228	Example: configure a node using a profile called seed, which si suitable
		229	for a seed node as it binds on all local addresses on a fixed port (4040,
		230	customary for aemp).
198		231
199	Example: become a public node listening on port C<4041>.	232	# use the aemp commandline utility
		233	# aemp profile seed nodeid anon/ binds '*:4040'
200		234
201	initialise_node 4041;	235	# then use it
		236	configure profile => "seed";
202		237
203	Example: become a public node, only visible on localhost port 4044.	238	# or simply use aemp from the shell again:
		239	# aemp run profile seed
204		240
205	initialise_node "locahost:4044";	241	# or provide a nicer-to-remember nodeid
206		242	# 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		243
240	=item $SELF	244	=item $SELF
241		245
242	Contains the current port id while executing C<rcv> callbacks or C<psub>	246	Contains the current port id while executing C<rcv> callbacks or C<psub>
243	blocks.	247	blocks.
244		248
245	=item SELF, %SELF, @SELF...	249	=item *SELF, SELF, %SELF, @SELF...
246		250
247	Due to some quirks in how perl exports variables, it is impossible to	251	Due to some quirks in how perl exports variables, it is impossible to
248	just export C<$SELF>, all the symbols called C<SELF> are exported by this	252	just export C<$SELF>, all the symbols named C<SELF> are exported by this
249	module, but only C<$SELF> is currently used.	253	module, but only C<$SELF> is currently used.
250		254
251	=item snd $port, type => @data	255	=item snd $port, type => @data
252		256
253	=item snd $port, @msg	257	=item snd $port, @msg
254		258
255	Send the given message to the given port ID, which can identify either	259	Send the given message to the given port, which can identify either a
256	a local or a remote port, and can be either a string or soemthignt hat	260	local or a remote port, and must be a port ID.
257	stringifies a sa port ID (such as a port object :).
258		261
259	While the message can be about anything, it is highly recommended to use a	262	While the message can be almost anything, it is highly recommended to
260	string as first element (a portid, or some word that indicates a request	263	use a string as first element (a port ID, or some word that indicates a
261	type etc.).	264	request type etc.) and to consist if only simple perl values (scalars,
		265	arrays, hashes) - if you think you need to pass an object, think again.
262		266
263	The message data effectively becomes read-only after a call to this	267	The message data logically becomes read-only after a call to this
264	function: modifying any argument is not allowed and can cause many	268	function: modifying any argument (or values referenced by them) is
265	problems.	269	forbidden, as there can be considerable time between the call to C<snd>
		270	and the time the message is actually being serialised - in fact, it might
		271	never be copied as within the same process it is simply handed to the
		272	receiving port.
266		273
267	The type of data you can transfer depends on the transport protocol: when	274	The type of data you can transfer depends on the transport protocol: when
268	JSON is used, then only strings, numbers and arrays and hashes consisting	275	JSON is used, then only strings, numbers and arrays and hashes consisting
269	of those are allowed (no objects). When Storable is used, then anything	276	of those are allowed (no objects). When Storable is used, then anything
270	that Storable can serialise and deserialise is allowed, and for the local	277	that Storable can serialise and deserialise is allowed, and for the local
271	node, anything can be passed.	278	node, anything can be passed. Best rely only on the common denominator of
		279	these.
272		280
273	=item $local_port = port	281	=item $local_port = port
274		282
275	Create a new local port object that can be used either as a pattern	283	Create a new local port object and returns its port ID. Initially it has
276	matching port ("full port") or a single-callback port ("miniport"),	284	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		285
279	=item $port = port { my @msg = @_; $finished }	286	=item $local_port = port { my @msg = @_ }
280		287
281	Creates a "miniport", that is, a very lightweight port without any pattern	288	Creates a new local port, and returns its ID. Semantically the same as
282	matching behind it, and returns its ID. Semantically the same as creating
283	a port and calling C<rcv $port, $callback> on it.	289	creating a port and calling C<rcv $port, $callback> on it.
284		290
285	The block will be called for every message received on the port. When the	291	The block will be called for every message received on the port, with the
286	callback returns a true value its job is considered "done" and the port	292	global variable C<$SELF> set to the port ID. Runtime errors will cause the
287	will be destroyed. Otherwise it will stay alive.	293	port to be C<kil>ed. The message will be passed as-is, no extra argument
		294	(i.e. no port ID) will be passed to the callback.
288		295
289	The message will be passed as-is, no extra argument (i.e. no port id) will	296	If you want to stop/destroy the port, simply C<kil> it:
290	be passed to the callback.
291		297
292	If you need the local port id in the callback, this works nicely:	298	my $port = port {
293		299	my @msg = @_;
294	my $port; $port = port {	300	...
295	snd $otherport, reply => $port;	301	kil $SELF;
296	};	302	};
297		303
298	=cut	304	=cut
299		305
300	sub rcv($@);	306	sub rcv($@);
		307
		308	sub _kilme {
		309	die "received message on port without callback";
		310	}
301		311
302	sub port(;&) {	312	sub port(;&) {
303	my $id = "$UNIQ." . $ID++;	313	my $id = "$UNIQ." . $ID++;
304	my $port = "$NODE#$id";	314	my $port = "$NODE#$id";
305		315
306	if (@_) {	316	rcv $port, shift \|\| \&_kilme;
307	rcv $port, shift;
308	} else {
309	$PORT{$id} = sub { }; # nop
310	}
311		317
312	$port	318	$port
313	}	319	}
314		320
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)	321	=item rcv $local_port, $callback->(@msg)
335		322
336	Replaces the callback on the specified miniport (after converting it to	323	Replaces the default callback on the specified port. There is no way to
337	one if required).	324	remove the default callback: use C<sub { }> to disable it, or better
338		325	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...] => $callback->(@msg), ...
344
345	Register callbacks to be called on matching messages on the given full
346	port (after converting it to one if required) and return the port.
347
348	The callback has to return a true value when its work is done, after
349	which is will be removed, or a false value in which case it will stay
350	registered.
351		326
352	The global C<$SELF> (exported by this module) contains C<$port> while	327	The global C<$SELF> (exported by this module) contains C<$port> while
353	executing the callback.	328	executing the callback. Runtime errors during callback execution will
		329	result in the port being C<kil>ed.
354		330
355	Runtime errors during callback execution will result in the port being	331	The default callback received all messages not matched by a more specific
356	C<kil>ed.	332	C<tag> match.
357		333
358	If the match is an array reference, then it will be matched against the	334	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
359	first elements of the message, otherwise only the first element is being
360	matched.
361		335
362	Any element in the match that is specified as C<_any_> (a function	336	Register (or replace) callbacks to be called on messages starting with the
363	exported by this module) matches any single element of the message.	337	given tag on the given port (and return the port), or unregister it (when
		338	C<$callback> is C<$undef> or missing). There can only be one callback
		339	registered for each tag.
364		340
365	While not required, it is highly recommended that the first matching	341	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	342	element (the tag) has been removed. The callback will use the same
367	also the most efficient match (by far).	343	environment as the default callback (see above).
368		344
369	Example: create a port and bind receivers on it in one go.	345	Example: create a port and bind receivers on it in one go.
370		346
371	my $port = rcv port,	347	my $port = rcv port,
372	msg1 => sub { ...; 0 },	348	msg1 => sub { ... },
373	msg2 => sub { ...; 0 },	349	msg2 => sub { ... },
374	;	350	;
375		351
376	Example: create a port, bind receivers and send it in a message elsewhere	352	Example: create a port, bind receivers and send it in a message elsewhere
377	in one go:	353	in one go:
378		354
379	snd $otherport, reply =>	355	snd $otherport, reply =>
380	rcv port,	356	rcv port,
381	msg1 => sub { ...; 0 },	357	msg1 => sub { ... },
382	...	358	...
383	;	359	;
384		360
		361	Example: temporarily register a rcv callback for a tag matching some port
		362	(e.g. for a rpc reply) and unregister it after a message was received.
		363
		364	rcv $port, $otherport => sub {
		365	my @reply = @_;
		366
		367	rcv $SELF, $otherport;
		368	};
		369
385	=cut	370	=cut
386		371
387	sub rcv($@) {	372	sub rcv($@) {
388	my $port = shift;	373	my $port = shift;
389	my ($noderef, $portid) = split /#/, $port, 2;	374	my ($nodeid, $portid) = split /#/, $port, 2;
390		375
391	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	376	$NODE{$nodeid} == $NODE{""}
392	or Carp::croak "$port: rcv can only be called on local ports, caught";	377	or Carp::croak "$port: rcv can only be called on local ports, caught";
393		378
394	if (@_ == 1) {	379	while (@_) {
		380	if (ref $_[0]) {
		381	if (my $self = $PORT_DATA{$portid}) {
		382	"AnyEvent::MP::Port" eq ref $self
		383	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		384
		385	$self->[2] = shift;
		386	} else {
395	my $cb = shift;	387	my $cb = shift;
396	delete $PORT_DATA{$portid};
397	$PORT{$portid} = sub {	388	$PORT{$portid} = sub {
398	local $SELF = $port;	389	local $SELF = $port;
399	eval {	390	eval { &$cb }; _self_die if $@;
400	&$cb	391	};
401	and kil $port;
402	};	392	}
403	_self_die if $@;	393	} elsif (defined $_[0]) {
404	};
405	} else {
406	my $self = $PORT_DATA{$portid} \|\|= do {	394	my $self = $PORT_DATA{$portid} \|\|= do {
407	my $self = bless {	395	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
408	id => $port,
409	}, "AnyEvent::MP::Port";
410		396
411	$PORT{$portid} = sub {	397	$PORT{$portid} = sub {
412	local $SELF = $port;	398	local $SELF = $port;
413		399
414	eval {
415	for (@{ $self->{rc0}{$_[0]} }) {	400	if (my $cb = $self->[1]{$_[0]}) {
416	$_ && &{$_->[0]}	401	shift;
417	&& undef $_;	402	eval { &$cb }; _self_die if $@;
418	}	403	} else {
419
420	for (@{ $self->{rcv}{$_[0]} }) {
421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
422	&& &{$_->[0]}	404	&{ $self->[0] };
423	&& undef $_;
424	}
425
426	for (@{ $self->{any} }) {
427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
428	&& &{$_->[0]}
429	&& undef $_;
430	}	405	}
431	};	406	};
432	_self_die if $@;	407
		408	$self
433	};	409	};
434		410
435	$self
436	};
437
438	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
439	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	412	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
440		413
441	while (@_) {
442	my ($match, $cb) = splice @_, 0, 2;	414	my ($tag, $cb) = splice @_, 0, 2;
443		415
444	if (!ref $match) {	416	if (defined $cb) {
445	push @{ $self->{rc0}{$match} }, [$cb];	417	$self->[1]{$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 {	418	} else {
452	push @{ $self->{any} }, [$cb, $match];	419	delete $self->[1]{$tag};
453	}	420	}
454	}	421	}
455	}	422	}
456		423
457	$port	424	$port
…		…
493	$res	460	$res
494	}	461	}
495	}	462	}
496	}	463	}
497		464
498	=item $guard = mon $port, $cb->(@reason)	465	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
499		466
500	=item $guard = mon $port, $rcvport	467	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
501		468
502	=item $guard = mon $port	469	=item $guard = mon $port # kill $SELF when $port dies
503		470
504	=item $guard = mon $port, $rcvport, @msg	471	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
505		472
506	Monitor the given port and do something when the port is killed, and	473	Monitor the given port and do something when the port is killed or
507	optionally return a guard that can be used to stop monitoring again.	474	messages to it were lost, and optionally return a guard that can be used
		475	to stop monitoring again.
		476
		477	C<mon> effectively guarantees that, in the absence of hardware failures,
		478	after starting the monitor, either all messages sent to the port will
		479	arrive, or the monitoring action will be invoked after possible message
		480	loss has been detected. No messages will be lost "in between" (after
		481	the first lost message no further messages will be received by the
		482	port). After the monitoring action was invoked, further messages might get
		483	delivered again.
		484
		485	Note that monitoring-actions are one-shot: once messages are lost (and a
		486	monitoring alert was raised), they are removed and will not trigger again.
508		487
509	In the first form (callback), the callback is simply called with any	488	In the first form (callback), the callback is simply called with any
510	number of C<@reason> elements (no @reason means that the port was deleted	489	number of C<@reason> elements (no @reason means that the port was deleted
511	"normally"). Note also that I<< the callback B<must> never die >>, so use	490	"normally"). Note also that I<< the callback B<must> never die >>, so use
512	C<eval> if unsure.	491	C<eval> if unsure.
513		492
514	In the second form (another port given), the other port (C<$rcvport)	493	In the second form (another port given), the other port (C<$rcvport>)
515	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	494	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
516	"normal" kils nothing happens, while under all other conditions, the other	495	"normal" kils nothing happens, while under all other conditions, the other
517	port is killed with the same reason.	496	port is killed with the same reason.
518		497
519	The third form (kill self) is the same as the second form, except that	498	The third form (kill self) is the same as the second form, except that
520	C<$rvport> defaults to C<$SELF>.	499	C<$rvport> defaults to C<$SELF>.
…		…
523	C<snd>.	502	C<snd>.
524		503
525	As a rule of thumb, monitoring requests should always monitor a port from	504	As a rule of thumb, monitoring requests should always monitor a port from
526	a local port (or callback). The reason is that kill messages might get	505	a local port (or callback). The reason is that kill messages might get
527	lost, just like any other message. Another less obvious reason is that	506	lost, just like any other message. Another less obvious reason is that
528	even monitoring requests can get lost (for exmaple, when the connection	507	even monitoring requests can get lost (for example, when the connection
529	to the other node goes down permanently). When monitoring a port locally	508	to the other node goes down permanently). When monitoring a port locally
530	these problems do not exist.	509	these problems do not exist.
531		510
532	Example: call a given callback when C<$port> is killed.	511	Example: call a given callback when C<$port> is killed.
533		512
…		…
542	mon $port, $self => "restart";	521	mon $port, $self => "restart";
543		522
544	=cut	523	=cut
545		524
546	sub mon {	525	sub mon {
547	my ($noderef, $port) = split /#/, shift, 2;	526	my ($nodeid, $port) = split /#/, shift, 2;
548		527
549	my $node = $NODE{$noderef} \|\| add_node $noderef;	528	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
550		529
551	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	530	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
552		531
553	unless (ref $cb) {	532	unless (ref $cb) {
554	if (@_) {	533	if (@_) {
555	# send a kill info message	534	# send a kill info message
556	my (@msg) = @_;	535	my (@msg) = ($cb, @_);
557	$cb = sub { snd @msg, @_ };	536	$cb = sub { snd @msg, @_ };
558	} else {	537	} else {
559	# simply kill other port	538	# simply kill other port
560	my $port = $cb;	539	my $port = $cb;
561	$cb = sub { kil $port, @_ if @_ };	540	$cb = sub { kil $port, @_ if @_ };
…		…
574	is killed, the references will be freed.	553	is killed, the references will be freed.
575		554
576	Optionally returns a guard that will stop the monitoring.	555	Optionally returns a guard that will stop the monitoring.
577		556
578	This function is useful when you create e.g. timers or other watchers and	557	This function is useful when you create e.g. timers or other watchers and
579	want to free them when the port gets killed:	558	want to free them when the port gets killed (note the use of C<psub>):
580		559
581	$port->rcv (start => sub {	560	$port->rcv (start => sub {
582	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	561	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
583	undef $timer if 0.9 < rand;	562	undef $timer if 0.9 < rand;
584	});	563	});
585	});	564	});
586		565
587	=cut	566	=cut
…		…
596		575
597	=item kil $port[, @reason]	576	=item kil $port[, @reason]
598		577
599	Kill the specified port with the given C<@reason>.	578	Kill the specified port with the given C<@reason>.
600		579
601	If no C<@reason> is specified, then the port is killed "normally" (linked	580	If no C<@reason> is specified, then the port is killed "normally" (ports
602	ports will not be kileld, or even notified).	581	monitoring other ports will not necessarily die because a port dies
		582	"normally").
603		583
604	Otherwise, linked ports get killed with the same reason (second form of	584	Otherwise, linked ports get killed with the same reason (second form of
605	C<mon>, see below).	585	C<mon>, see above).
606		586
607	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	587	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
608	will be reported as reason C<< die => $@ >>.	588	will be reported as reason C<< die => $@ >>.
609		589
610	Transport/communication errors are reported as C<< transport_error =>	590	Transport/communication errors are reported as C<< transport_error =>
…		…
615	=item $port = spawn $node, $initfunc[, @initdata]	595	=item $port = spawn $node, $initfunc[, @initdata]
616		596
617	Creates a port on the node C<$node> (which can also be a port ID, in which	597	Creates a port on the node C<$node> (which can also be a port ID, in which
618	case it's the node where that port resides).	598	case it's the node where that port resides).
619		599
620	The port ID of the newly created port is return immediately, and it is	600	The port ID of the newly created port is returned immediately, and it is
621	permissible to immediately start sending messages or monitor the port.	601	possible to immediately start sending messages or to monitor the port.
622		602
623	After the port has been created, the init function is	603	After the port has been created, the init function is called on the remote
624	called. This fucntion must be a fully-qualified function name	604	node, in the same context as a C<rcv> callback. This function must be a
625	(e.g. C<MyApp::Chat::Server::init>).	605	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		606	specify a function in the main program, use C<::name>.
626		607
627	If the function doesn't exist, then the node tries to C<require>	608	If the function doesn't exist, then the node tries to C<require>
628	the package, then the package above the package and so on (e.g.	609	the package, then the package above the package and so on (e.g.
629	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	610	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
630	exists or it runs out of package names.	611	exists or it runs out of package names.
631		612
632	The init function is then called with the newly-created port as context	613	The init function is then called with the newly-created port as context
633	object (C<$SELF>) and the C<@initdata> values as arguments.	614	object (C<$SELF>) and the C<@initdata> values as arguments.
634		615
635	A common idiom is to pass your own port, monitor the spawned port, and	616	A common idiom is to pass a local port, immediately monitor the spawned
636	in the init function, monitor the original port. This two-way monitoring	617	port, and in the remote init function, immediately monitor the passed
637	ensures that both ports get cleaned up when there is a problem.	618	local port. This two-way monitoring ensures that both ports get cleaned up
		619	when there is a problem.
638		620
639	Example: spawn a chat server port on C<$othernode>.	621	Example: spawn a chat server port on C<$othernode>.
640		622
641	# this node, executed from within a port context:	623	# this node, executed from within a port context:
642	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	624	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
665	};	647	};
666	_self_die if $@;	648	_self_die if $@;
667	}	649	}
668		650
669	sub spawn(@) {	651	sub spawn(@) {
670	my ($noderef, undef) = split /#/, shift, 2;	652	my ($nodeid, undef) = split /#/, shift, 2;
671		653
672	my $id = "$RUNIQ." . $ID++;	654	my $id = "$RUNIQ." . $ID++;
673		655
674	($NODE{$noderef} \|\| add_node $noderef)	656	$_[0] =~ /::/
675	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);	657	or Carp::croak "spawn init function must be a fully-qualified name, caught";
676		658
		659	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
		660
677	"$noderef#$id"	661	"$nodeid#$id"
678	}	662	}
679		663
680	=back	664	=item after $timeout, @msg
681		665
682	=head1 NODE MESSAGES	666	=item after $timeout, $callback
683		667
684	Nodes understand the following messages sent to them. Many of them take	668	Either sends the given message, or call the given callback, after the
685	arguments called C<@reply>, which will simply be used to compose a reply	669	specified number of seconds.
686	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
687	the remaining arguments are simply the message data.
688		670
689	While other messages exist, they are not public and subject to change.	671	This is simply a utility function that comes in handy at times - the
		672	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		673	so it may go away in the future.
690		674
691	=over 4
692
693	=cut	675	=cut
694		676
695	=item lookup => $name, @reply	677	sub after($@) {
		678	my ($timeout, @action) = @_;
696		679
697	Replies with the port ID of the specified well-known port, or C<undef>.	680	my $t; $t = AE::timer $timeout, 0, sub {
698		681	undef $t;
699	=item devnull => ...	682	ref $action[0]
700		683	? $action[0]()
701	Generic data sink/CPU heat conversion.	684	: snd @action;
702		685	};
703	=item relay => $port, @msg	686	}
704
705	Simply forwards the message to the given port.
706
707	=item eval => $string[ @reply]
708
709	Evaluates the given string. If C<@reply> is given, then a message of the
710	form C<@reply, $@, @evalres> is sent.
711
712	Example: crash another node.
713
714	snd $othernode, eval => "exit";
715
716	=item time => @reply
717
718	Replies the the current node time to C<@reply>.
719
720	Example: tell the current node to send the current time to C<$myport> in a
721	C<timereply> message.
722
723	snd $NODE, time => $myport, timereply => 1, 2;
724	# => snd $myport, timereply => 1, 2, <time>
725		687
726	=back	688	=back
727		689
728	=head1 AnyEvent::MP vs. Distributed Erlang	690	=head1 AnyEvent::MP vs. Distributed Erlang
729		691
…		…
739		701
740	Despite the similarities, there are also some important differences:	702	Despite the similarities, there are also some important differences:
741		703
742	=over 4	704	=over 4
743		705
744	=item * Node references contain the recipe on how to contact them.	706	=item * Node IDs are arbitrary strings in AEMP.
745		707
746	Erlang relies on special naming and DNS to work everywhere in the	708	Erlang relies on special naming and DNS to work everywhere in the same
747	same way. AEMP relies on each node knowing it's own address(es), with	709	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
748	convenience functionality.	710	configuration or DNS), but will otherwise discover other odes itself.
749		711
750	This means that AEMP requires a less tightly controlled environment at the	712	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
751	cost of longer node references and a slightly higher management overhead.	713	uses "local ports are like remote ports".
		714
		715	The failure modes for local ports are quite different (runtime errors
		716	only) then for remote ports - when a local port dies, you I<know> it dies,
		717	when a connection to another node dies, you know nothing about the other
		718	port.
		719
		720	Erlang pretends remote ports are as reliable as local ports, even when
		721	they are not.
		722
		723	AEMP encourages a "treat remote ports differently" philosophy, with local
		724	ports being the special case/exception, where transport errors cannot
		725	occur.
752		726
753	=item * Erlang uses processes and a mailbox, AEMP does not queue.	727	=item * Erlang uses processes and a mailbox, AEMP does not queue.
754		728
755	Erlang uses processes that selctively receive messages, and therefore	729	Erlang uses processes that selectively receive messages, and therefore
756	needs a queue. AEMP is event based, queuing messages would serve no useful	730	needs a queue. AEMP is event based, queuing messages would serve no
757	purpose.	731	useful purpose. For the same reason the pattern-matching abilities of
		732	AnyEvent::MP are more limited, as there is little need to be able to
		733	filter messages without dequeuing them.
758		734
759	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	735	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
760		736
761	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	737	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
762		738
763	Sending messages in Erlang is synchronous and blocks the process. AEMP	739	Sending messages in Erlang is synchronous and blocks the process (and
764	sends are immediate, connection establishment is handled in the	740	so does not need a queue that can overflow). AEMP sends are immediate,
765	background.	741	connection establishment is handled in the background.
766		742
767	=item * Erlang can silently lose messages, AEMP cannot.	743	=item * Erlang suffers from silent message loss, AEMP does not.
768		744
769	Erlang makes few guarantees on messages delivery - messages can get lost	745	Erlang makes few guarantees on messages delivery - messages can get lost
770	without any of the processes realising it (i.e. you send messages a, b,	746	without any of the processes realising it (i.e. you send messages a, b,
771	and c, and the other side only receives messages a and c).	747	and c, and the other side only receives messages a and c).
772		748
773	AEMP guarantees correct ordering, and the guarantee that there are no	749	AEMP guarantees correct ordering, and the guarantee that after one message
774	holes in the message sequence.	750	is lost, all following ones sent to the same port are lost as well, until
775		751	monitoring raises an error, so there are no silent "holes" in the message
776	=item * In Erlang, processes can be declared dead and later be found to be	752	sequence.
777	alive.
778
779	In Erlang it can happen that a monitored process is declared dead and
780	linked processes get killed, but later it turns out that the process is
781	still alive - and can receive messages.
782
783	In AEMP, when port monitoring detects a port as dead, then that port will
784	eventually be killed - it cannot happen that a node detects a port as dead
785	and then later sends messages to it, finding it is still alive.
786		753
787	=item * Erlang can send messages to the wrong port, AEMP does not.	754	=item * Erlang can send messages to the wrong port, AEMP does not.
788		755
789	In Erlang it is quite possible that a node that restarts reuses a process	756	In Erlang it is quite likely that a node that restarts reuses a process ID
790	ID known to other nodes for a completely different process, causing	757	known to other nodes for a completely different process, causing messages
791	messages destined for that process to end up in an unrelated process.	758	destined for that process to end up in an unrelated process.
792		759
793	AEMP never reuses port IDs, so old messages or old port IDs floating	760	AEMP never reuses port IDs, so old messages or old port IDs floating
794	around in the network will not be sent to an unrelated port.	761	around in the network will not be sent to an unrelated port.
795		762
796	=item * Erlang uses unprotected connections, AEMP uses secure	763	=item * Erlang uses unprotected connections, AEMP uses secure
797	authentication and can use TLS.	764	authentication and can use TLS.
798		765
799	AEMP can use a proven protocol - SSL/TLS - to protect connections and	766	AEMP can use a proven protocol - TLS - to protect connections and
800	securely authenticate nodes.	767	securely authenticate nodes.
801		768
802	=item * The AEMP protocol is optimised for both text-based and binary	769	=item * The AEMP protocol is optimised for both text-based and binary
803	communications.	770	communications.
804		771
805	The AEMP protocol, unlike the Erlang protocol, supports both	772	The AEMP protocol, unlike the Erlang protocol, supports both programming
806	language-independent text-only protocols (good for debugging) and binary,	773	language independent text-only protocols (good for debugging) and binary,
807	language-specific serialisers (e.g. Storable).	774	language-specific serialisers (e.g. Storable). By default, unless TLS is
		775	used, the protocol is actually completely text-based.
808		776
809	It has also been carefully designed to be implementable in other languages	777	It has also been carefully designed to be implementable in other languages
810	with a minimum of work while gracefully degrading fucntionality to make the	778	with a minimum of work while gracefully degrading functionality to make the
811	protocol simple.	779	protocol simple.
812		780
813	=item * AEMP has more flexible monitoring options than Erlang.	781	=item * AEMP has more flexible monitoring options than Erlang.
814		782
815	In Erlang, you can chose to receive I<all> exit signals as messages	783	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
818	Erlang, as one can choose between automatic kill, exit message or callback	786	Erlang, as one can choose between automatic kill, exit message or callback
819	on a per-process basis.	787	on a per-process basis.
820		788
821	=item * Erlang tries to hide remote/local connections, AEMP does not.	789	=item * Erlang tries to hide remote/local connections, AEMP does not.
822		790
823	Monitoring in Erlang is not an indicator of process death/crashes,	791	Monitoring in Erlang is not an indicator of process death/crashes, in the
824	as linking is (except linking is unreliable in Erlang).	792	same way as linking is (except linking is unreliable in Erlang).
825		793
826	In AEMP, you don't "look up" registered port names or send to named ports	794	In AEMP, you don't "look up" registered port names or send to named ports
827	that might or might not be persistent. Instead, you normally spawn a port	795	that might or might not be persistent. Instead, you normally spawn a port
828	on the remote node. The init function monitors the you, and you monitor	796	on the remote node. The init function monitors you, and you monitor the
829	the remote port. Since both monitors are local to the node, they are much	797	remote port. Since both monitors are local to the node, they are much more
830	more reliable.	798	reliable (no need for C<spawn_link>).
831		799
832	This also saves round-trips and avoids sending messages to the wrong port	800	This also saves round-trips and avoids sending messages to the wrong port
833	(hard to do in Erlang).	801	(hard to do in Erlang).
834		802
835	=back	803	=back
836		804
		805	=head1 RATIONALE
		806
		807	=over 4
		808
		809	=item Why strings for port and node IDs, why not objects?
		810
		811	We considered "objects", but found that the actual number of methods
		812	that can be called are quite low. Since port and node IDs travel over
		813	the network frequently, the serialising/deserialising would add lots of
		814	overhead, as well as having to keep a proxy object everywhere.
		815
		816	Strings can easily be printed, easily serialised etc. and need no special
		817	procedures to be "valid".
		818
		819	And as a result, a miniport consists of a single closure stored in a
		820	global hash - it can't become much cheaper.
		821
		822	=item Why favour JSON, why not a real serialising format such as Storable?
		823
		824	In fact, any AnyEvent::MP node will happily accept Storable as framing
		825	format, but currently there is no way to make a node use Storable by
		826	default (although all nodes will accept it).
		827
		828	The default framing protocol is JSON because a) JSON::XS is many times
		829	faster for small messages and b) most importantly, after years of
		830	experience we found that object serialisation is causing more problems
		831	than it solves: Just like function calls, objects simply do not travel
		832	easily over the network, mostly because they will always be a copy, so you
		833	always have to re-think your design.
		834
		835	Keeping your messages simple, concentrating on data structures rather than
		836	objects, will keep your messages clean, tidy and efficient.
		837
		838	=back
		839
837	=head1 SEE ALSO	840	=head1 SEE ALSO
		841
		842	L<AnyEvent::MP::Intro> - a gentle introduction.
		843
		844	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		845
		846	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		847	your applications.
838		848
839	L<AnyEvent>.	849	L<AnyEvent>.
840		850
841	=head1 AUTHOR	851	=head1 AUTHOR
842		852

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC vs. Revision 1.77 by elmex, Thu Sep 3 07:57:30 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.38 by root, Fri Aug 7 22:55:18 2009 UTC vs.
Revision 1.77 by elmex, Thu Sep 3 07:57:30 2009 UTC