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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
		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
28	# linking two ports, so they both crash together
29	lnk $port1, $port2;
30		34
31	# monitoring	35	# monitoring
32	mon $port, $cb->(@msg) # callback is invoked on death	36	mon $port, $cb->(@msg) # callback is invoked on death
33	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
34	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
35		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
36	=head1 DESCRIPTION	50	=head1 DESCRIPTION
37		51
38	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
39		53
40	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
41	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
42		56
43	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>
44	manual page.	58	manual page and the examples under F<eg/>.
45
46	At the moment, this module family is severly broken and underdocumented,
47	so do not use. This was uploaded mainly to reserve the CPAN namespace -
48	stay tuned! The basic API should be finished, however.
49		59
50	=head1 CONCEPTS	60	=head1 CONCEPTS
51		61
52	=over 4	62	=over 4
53		63
54	=item port	64	=item port
55		65
56	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).
57		67
58	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
59	messages. All C<rcv> handlers will receive messages they match, messages	69	some messages. Messages send to ports will not be queued, regardless of
60	will not be queued.	70	anything was listening for them or not.
61		71
62	=item port id - C<noderef#portname>	72	=item port ID - C<nodeid#portname>
63		73
64	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
65	separator, and a port name (a printable string of unspecified format). An	75	separator, and a port name (a printable string of unspecified format).
66	exception is the the node port, whose ID is identical to its node
67	reference.
68		76
69	=item node	77	=item node
70		78
71	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,
72	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
73	create new ports, among other things.	81	ports.
74		82
75	Nodes are either private (single-process only), slaves (connected to a	83	Nodes are either public (have one or more listening ports) or private
76	master node only) or public nodes (connectable from unrelated nodes).	84	(no listening ports). Private nodes cannot talk to other private nodes
		85	currently.
77		86
78	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	87	=item node ID - C<[a-za-Z0-9_\-.:]+>
79		88
80	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
81	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
82	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.
83		93
84	This recipe is simply a comma-separated list of C<address:port> pairs (for	94	=item binds - C<ip:port>
85	TCP/IP, other protocols might look different).
86		95
87	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
88	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.
89		100
90	Before using an unresolved node reference in a message you first have to	101	=item seeds - C<host:port>
91	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.
92		115
93	=back	116	=back
94		117
95	=head1 VARIABLES/FUNCTIONS	118	=head1 VARIABLES/FUNCTIONS
96		119
…		…
98		121
99	=cut	122	=cut
100		123
101	package AnyEvent::MP;	124	package AnyEvent::MP;
102		125
103	use AnyEvent::MP::Base;	126	use AnyEvent::MP::Kernel;
104		127
105	use common::sense;	128	use common::sense;
106		129
107	use Carp ();	130	use Carp ();
108		131
109	use AE ();	132	use AE ();
110		133
111	use base "Exporter";	134	use base "Exporter";
112		135
113	our $VERSION = '0.1';	136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		137
114	our @EXPORT = qw(	138	our @EXPORT = qw(
115	NODE $NODE *SELF node_of _any_	139	NODE $NODE *SELF node_of after
116	resolve_node initialise_node	140	configure
117	snd rcv mon kil reg psub	141	snd rcv mon mon_guard kil reg psub spawn
118	port	142	port
119	);	143	);
120		144
121	our $SELF;	145	our $SELF;
122		146
…		…
126	kil $SELF, die => $msg;	150	kil $SELF, die => $msg;
127	}	151	}
128		152
129	=item $thisnode = NODE / $NODE	153	=item $thisnode = NODE / $NODE
130		154
131	The C<NODE> function returns, and the C<$NODE> variable contains	155	The C<NODE> function returns, and the C<$NODE> variable contains, the node
132	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
133	to C<become_public> or C<become_slave>, after which all local port	157	a call to C<configure>.
134	identifiers become invalid.
135		158
136	=item $noderef = node_of $port	159	=item $nodeid = node_of $port
137		160
138	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.
139		162
140	=item initialise_node $noderef, $seednode, $seednode...	163	=item configure $profile, key => value...
141		164
142	=item initialise_node "slave/", $master, $master...	165	=item configure key => value...
143		166
144	Before a node can talk to other nodes on the network it has to initialise	167	Before a node can talk to other nodes on the network (i.e. enter
145	itself - the minimum a node needs to know is it's own name, and optionally	168	"distributed mode") it has to configure itself - the minimum a node needs
146	it should know the noderefs of some other nodes in the network.	169	to know is its own name, and optionally it should know the addresses of
		170	some other nodes in the network to discover other nodes.
147		171
148	This function initialises a node - it must be called exactly once (or	172	This function configures a node - it must be called exactly once (or
149	never) before calling other AnyEvent::MP functions.	173	never) before calling other AnyEvent::MP functions.
150		174
151	All arguments are noderefs, which can be either resolved or unresolved.
152
153	There are two types of networked nodes, public nodes and slave nodes:
154
155	=over 4	175	=over 4
156		176
157	=item public nodes	177	=item step 1, gathering configuration from profiles
158		178
159	For public nodes, C<$noderef> must either be a (possibly unresolved)	179	The function first looks up a profile in the aemp configuration (see the
160	noderef, in which case it will be resolved, or C<undef> (or missing), in	180	L<aemp> commandline utility). The profile name can be specified via the
161	which case the noderef will be guessed.	181	named C<profile> parameter or can simply be the first parameter). If it is
		182	missing, then the nodename (F<uname -n>) will be used as profile name.
162		183
163	Afterwards, the node will bind itself on all endpoints and try to connect	184	The profile data is then gathered as follows:
164	to all additional C<$seednodes> that are specified. Seednodes are optional
165	and can be used to quickly bootstrap the node into an existing network.
166		185
167	=item slave nodes	186	First, all remaining key => value pairs (all of which are conveniently
		187	undocumented at the moment) will be interpreted as configuration
		188	data. Then they will be overwritten by any values specified in the global
		189	default configuration (see the F<aemp> utility), then the chain of
		190	profiles chosen by the profile name (and any C<parent> attributes).
168		191
169	When the C<$noderef> is the special string C<slave/>, then the node will	192	That means that the values specified in the profile have highest priority
170	become a slave node. Slave nodes cannot be contacted from outside and will	193	and the values specified directly via C<configure> have lowest priority,
171	route most of their traffic to the master node that they attach to.	194	and can only be used to specify defaults.
172		195
173	At least one additional noderef is required: The node will try to connect	196	If the profile specifies a node ID, then this will become the node ID of
174	to all of them and will become a slave attached to the first node it can	197	this process. If not, then the profile name will be used as node ID. The
175	successfully connect to.	198	special node ID of C<anon/> will be replaced by a random node ID.
		199
		200	=item step 2, bind listener sockets
		201
		202	The next step is to look up the binds in the profile, followed by binding
		203	aemp protocol listeners on all binds specified (it is possible and valid
		204	to have no binds, meaning that the node cannot be contacted form the
		205	outside. This means the node cannot talk to other nodes that also have no
		206	binds, but it can still talk to all "normal" nodes).
		207
		208	If the profile does not specify a binds list, then a default of C<*> is
		209	used, meaning the node will bind on a dynamically-assigned port on every
		210	local IP address it finds.
		211
		212	=item step 3, connect to seed nodes
		213
		214	As the last step, the seeds list from the profile is passed to the
		215	L<AnyEvent::MP::Global> module, which will then use it to keep
		216	connectivity with at least one node at any point in time.
176		217
177	=back	218	=back
178		219
179	This function will block until all nodes have been resolved and, for slave	220	Example: become a distributed node using the locla node name as profile.
180	nodes, until it has successfully established a connection to a master	221	This should be the most common form of invocation for "daemon"-type nodes.
181	server.
182		222
183	Example: become a public node listening on the default node.	223	configure
184		224
185	initialise_node;	225	Example: become an anonymous node. This form is often used for commandline
		226	clients.
186		227
187	Example: become a public node, and try to contact some well-known master	228	configure nodeid => "anon/";
188	servers to become part of the network.
189		229
190	initialise_node undef, "master1", "master2";	230	Example: configure a node using a profile called seed, which si suitable
		231	for a seed node as it binds on all local addresses on a fixed port (4040,
		232	customary for aemp).
191		233
192	Example: become a public node listening on port C<4041>.	234	# use the aemp commandline utility
		235	# aemp profile seed nodeid anon/ binds '*:4040'
193		236
194	initialise_node 4041;	237	# then use it
		238	configure profile => "seed";
195		239
196	Example: become a public node, only visible on localhost port 4044.	240	# or simply use aemp from the shell again:
		241	# aemp run profile seed
197		242
198	initialise_node "locahost:4044";	243	# or provide a nicer-to-remember nodeid
199		244	# aemp run profile seed nodeid "$(hostname)"
200	Example: become a slave node to any of the specified master servers.
201
202	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
203
204	=item $cv = resolve_node $noderef
205
206	Takes an unresolved node reference that may contain hostnames and
207	abbreviated IDs, resolves all of them and returns a resolved node
208	reference.
209
210	In addition to C<address:port> pairs allowed in resolved noderefs, the
211	following forms are supported:
212
213	=over 4
214
215	=item the empty string
216
217	An empty-string component gets resolved as if the default port (4040) was
218	specified.
219
220	=item naked port numbers (e.g. C<1234>)
221
222	These are resolved by prepending the local nodename and a colon, to be
223	further resolved.
224
225	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
226
227	These are resolved by using AnyEvent::DNS to resolve them, optionally
228	looking up SRV records for the C<aemp=4040> port, if no port was
229	specified.
230
231	=back
232		245
233	=item $SELF	246	=item $SELF
234		247
235	Contains the current port id while executing C<rcv> callbacks or C<psub>	248	Contains the current port id while executing C<rcv> callbacks or C<psub>
236	blocks.	249	blocks.
237		250
238	=item SELF, %SELF, @SELF...	251	=item *SELF, SELF, %SELF, @SELF...
239		252
240	Due to some quirks in how perl exports variables, it is impossible to	253	Due to some quirks in how perl exports variables, it is impossible to
241	just export C<$SELF>, all the symbols called C<SELF> are exported by this	254	just export C<$SELF>, all the symbols named C<SELF> are exported by this
242	module, but only C<$SELF> is currently used.	255	module, but only C<$SELF> is currently used.
243		256
244	=item snd $port, type => @data	257	=item snd $port, type => @data
245		258
246	=item snd $port, @msg	259	=item snd $port, @msg
247		260
248	Send the given message to the given port ID, which can identify either	261	Send the given message to the given port, which can identify either a
249	a local or a remote port, and can be either a string or soemthignt hat	262	local or a remote port, and must be a port ID.
250	stringifies a sa port ID (such as a port object :).
251		263
252	While the message can be about anything, it is highly recommended to use a	264	While the message can be almost anything, it is highly recommended to
253	string as first element (a portid, or some word that indicates a request	265	use a string as first element (a port ID, or some word that indicates a
254	type etc.).	266	request type etc.) and to consist if only simple perl values (scalars,
		267	arrays, hashes) - if you think you need to pass an object, think again.
255		268
256	The message data effectively becomes read-only after a call to this	269	The message data logically becomes read-only after a call to this
257	function: modifying any argument is not allowed and can cause many	270	function: modifying any argument (or values referenced by them) is
258	problems.	271	forbidden, as there can be considerable time between the call to C<snd>
		272	and the time the message is actually being serialised - in fact, it might
		273	never be copied as within the same process it is simply handed to the
		274	receiving port.
259		275
260	The type of data you can transfer depends on the transport protocol: when	276	The type of data you can transfer depends on the transport protocol: when
261	JSON is used, then only strings, numbers and arrays and hashes consisting	277	JSON is used, then only strings, numbers and arrays and hashes consisting
262	of those are allowed (no objects). When Storable is used, then anything	278	of those are allowed (no objects). When Storable is used, then anything
263	that Storable can serialise and deserialise is allowed, and for the local	279	that Storable can serialise and deserialise is allowed, and for the local
264	node, anything can be passed.	280	node, anything can be passed. Best rely only on the common denominator of
		281	these.
265		282
266	=item $local_port = port	283	=item $local_port = port
267		284
268	Create a new local port object that can be used either as a pattern	285	Create a new local port object and returns its port ID. Initially it has
269	matching port ("full port") or a single-callback port ("miniport"),	286	no callbacks set and will throw an error when it receives messages.
270	depending on how C<rcv> callbacks are bound to the object.
271		287
272	=item $port = port { my @msg = @_; $finished }	288	=item $local_port = port { my @msg = @_ }
273		289
274	Creates a "miniport", that is, a very lightweight port without any pattern	290	Creates a new local port, and returns its ID. Semantically the same as
275	matching behind it, and returns its ID. Semantically the same as creating
276	a port and calling C<rcv $port, $callback> on it.	291	creating a port and calling C<rcv $port, $callback> on it.
277		292
278	The block will be called for every message received on the port. When the	293	The block will be called for every message received on the port, with the
279	callback returns a true value its job is considered "done" and the port	294	global variable C<$SELF> set to the port ID. Runtime errors will cause the
280	will be destroyed. Otherwise it will stay alive.	295	port to be C<kil>ed. The message will be passed as-is, no extra argument
		296	(i.e. no port ID) will be passed to the callback.
281		297
282	The message will be passed as-is, no extra argument (i.e. no port id) will	298	If you want to stop/destroy the port, simply C<kil> it:
283	be passed to the callback.
284		299
285	If you need the local port id in the callback, this works nicely:	300	my $port = port {
286		301	my @msg = @_;
287	my $port; $port = port {	302	...
288	snd $otherport, reply => $port;	303	kil $SELF;
289	};	304	};
290		305
291	=cut	306	=cut
292		307
293	sub rcv($@);	308	sub rcv($@);
		309
		310	sub _kilme {
		311	die "received message on port without callback";
		312	}
294		313
295	sub port(;&) {	314	sub port(;&) {
296	my $id = "$UNIQ." . $ID++;	315	my $id = "$UNIQ." . $ID++;
297	my $port = "$NODE#$id";	316	my $port = "$NODE#$id";
298		317
299	if (@_) {	318	rcv $port, shift \|\| \&_kilme;
300	rcv $port, shift;
301	} else {
302	$PORT{$id} = sub { }; # nop
303	}
304		319
305	$port	320	$port
306	}	321	}
307		322
308	=item reg $port, $name
309
310	=item reg $name
311
312	Registers the given port (or C<$SELF><<< if missing) under the name
313	C<$name>. If the name already exists it is replaced.
314
315	A port can only be registered under one well known name.
316
317	A port automatically becomes unregistered when it is killed.
318
319	=cut
320
321	sub reg(@) {
322	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
323
324	$REG{$_[0]} = $port;
325	}
326
327	=item rcv $port, $callback->(@msg)	323	=item rcv $local_port, $callback->(@msg)
328		324
329	Replaces the callback on the specified miniport (after converting it to	325	Replaces the default callback on the specified port. There is no way to
330	one if required).	326	remove the default callback: use C<sub { }> to disable it, or better
331		327	C<kil> the port when it is no longer needed.
332	=item rcv $port, tagstring => $callback->(@msg), ...
333
334	=item rcv $port, $smartmatch => $callback->(@msg), ...
335
336	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
337
338	Register callbacks to be called on matching messages on the given full
339	port (after converting it to one if required) and return the port.
340
341	The callback has to return a true value when its work is done, after
342	which is will be removed, or a false value in which case it will stay
343	registered.
344		328
345	The global C<$SELF> (exported by this module) contains C<$port> while	329	The global C<$SELF> (exported by this module) contains C<$port> while
346	executing the callback.	330	executing the callback. Runtime errors during callback execution will
		331	result in the port being C<kil>ed.
347		332
348	Runtime errors wdurign callback execution will result in the port being	333	The default callback received all messages not matched by a more specific
349	C<kil>ed.	334	C<tag> match.
350		335
351	If the match is an array reference, then it will be matched against the	336	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
352	first elements of the message, otherwise only the first element is being
353	matched.
354		337
355	Any element in the match that is specified as C<_any_> (a function	338	Register (or replace) callbacks to be called on messages starting with the
356	exported by this module) matches any single element of the message.	339	given tag on the given port (and return the port), or unregister it (when
		340	C<$callback> is C<$undef> or missing). There can only be one callback
		341	registered for each tag.
357		342
358	While not required, it is highly recommended that the first matching	343	The original message will be passed to the callback, after the first
359	element is a string identifying the message. The one-string-only match is	344	element (the tag) has been removed. The callback will use the same
360	also the most efficient match (by far).	345	environment as the default callback (see above).
361		346
362	Example: create a port and bind receivers on it in one go.	347	Example: create a port and bind receivers on it in one go.
363		348
364	my $port = rcv port,	349	my $port = rcv port,
365	msg1 => sub { ...; 0 },	350	msg1 => sub { ... },
366	msg2 => sub { ...; 0 },	351	msg2 => sub { ... },
367	;	352	;
368		353
369	Example: create a port, bind receivers and send it in a message elsewhere	354	Example: create a port, bind receivers and send it in a message elsewhere
370	in one go:	355	in one go:
371		356
372	snd $otherport, reply =>	357	snd $otherport, reply =>
373	rcv port,	358	rcv port,
374	msg1 => sub { ...; 0 },	359	msg1 => sub { ... },
375	...	360	...
376	;	361	;
377		362
		363	Example: temporarily register a rcv callback for a tag matching some port
		364	(e.g. for a rpc reply) and unregister it after a message was received.
		365
		366	rcv $port, $otherport => sub {
		367	my @reply = @_;
		368
		369	rcv $SELF, $otherport;
		370	};
		371
378	=cut	372	=cut
379		373
380	sub rcv($@) {	374	sub rcv($@) {
381	my $port = shift;	375	my $port = shift;
382	my ($noderef, $portid) = split /#/, $port, 2;	376	my ($nodeid, $portid) = split /#/, $port, 2;
383		377
384	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	378	$NODE{$nodeid} == $NODE{""}
385	or Carp::croak "$port: rcv can only be called on local ports, caught";	379	or Carp::croak "$port: rcv can only be called on local ports, caught";
386		380
387	if (@_ == 1) {	381	while (@_) {
		382	if (ref $_[0]) {
		383	if (my $self = $PORT_DATA{$portid}) {
		384	"AnyEvent::MP::Port" eq ref $self
		385	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		386
		387	$self->[2] = shift;
		388	} else {
388	my $cb = shift;	389	my $cb = shift;
389	delete $PORT_DATA{$portid};
390	$PORT{$portid} = sub {	390	$PORT{$portid} = sub {
391	local $SELF = $port;	391	local $SELF = $port;
392	eval {	392	eval { &$cb }; _self_die if $@;
393	&$cb	393	};
394	and kil $port;
395	};	394	}
396	_self_die if $@;	395	} elsif (defined $_[0]) {
397	};
398	} else {
399	my $self = $PORT_DATA{$portid} \|\|= do {	396	my $self = $PORT_DATA{$portid} \|\|= do {
400	my $self = bless {	397	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
401	id => $port,
402	}, "AnyEvent::MP::Port";
403		398
404	$PORT{$portid} = sub {	399	$PORT{$portid} = sub {
405	local $SELF = $port;	400	local $SELF = $port;
406		401
407	eval {
408	for (@{ $self->{rc0}{$_[0]} }) {	402	if (my $cb = $self->[1]{$_[0]}) {
409	$_ && &{$_->[0]}	403	shift;
410	&& undef $_;	404	eval { &$cb }; _self_die if $@;
411	}	405	} else {
412
413	for (@{ $self->{rcv}{$_[0]} }) {
414	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
415	&& &{$_->[0]}	406	&{ $self->[0] };
416	&& undef $_;
417	}
418
419	for (@{ $self->{any} }) {
420	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
421	&& &{$_->[0]}
422	&& undef $_;
423	}	407	}
424	};	408	};
425	_self_die if $@;	409
		410	$self
426	};	411	};
427		412
428	$self
429	};
430
431	"AnyEvent::MP::Port" eq ref $self	413	"AnyEvent::MP::Port" eq ref $self
432	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
433		415
434	while (@_) {
435	my ($match, $cb) = splice @_, 0, 2;	416	my ($tag, $cb) = splice @_, 0, 2;
436		417
437	if (!ref $match) {	418	if (defined $cb) {
438	push @{ $self->{rc0}{$match} }, [$cb];	419	$self->[1]{$tag} = $cb;
439	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
440	my ($type, @match) = @$match;
441	@match
442	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
443	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
444	} else {	420	} else {
445	push @{ $self->{any} }, [$cb, $match];	421	delete $self->[1]{$tag};
446	}	422	}
447	}	423	}
448	}	424	}
449		425
450	$port	426	$port
…		…
486	$res	462	$res
487	}	463	}
488	}	464	}
489	}	465	}
490		466
491	=item $guard = mon $port, $cb->(@reason)	467	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
492		468
493	=item $guard = mon $port, $rcvport	469	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
494		470
495	=item $guard = mon $port	471	=item $guard = mon $port # kill $SELF when $port dies
496		472
497	=item $guard = mon $port, $rcvport, @msg	473	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
498		474
499	Monitor the given port and do something when the port is killed, and	475	Monitor the given port and do something when the port is killed or
500	optionally return a guard that can be used to stop monitoring again.	476	messages to it were lost, and optionally return a guard that can be used
		477	to stop monitoring again.
		478
		479	C<mon> effectively guarantees that, in the absence of hardware failures,
		480	after starting the monitor, either all messages sent to the port will
		481	arrive, or the monitoring action will be invoked after possible message
		482	loss has been detected. No messages will be lost "in between" (after
		483	the first lost message no further messages will be received by the
		484	port). After the monitoring action was invoked, further messages might get
		485	delivered again.
		486
		487	Note that monitoring-actions are one-shot: once messages are lost (and a
		488	monitoring alert was raised), they are removed and will not trigger again.
501		489
502	In the first form (callback), the callback is simply called with any	490	In the first form (callback), the callback is simply called with any
503	number of C<@reason> elements (no @reason means that the port was deleted	491	number of C<@reason> elements (no @reason means that the port was deleted
504	"normally"). Note also that I<< the callback B<must> never die >>, so use	492	"normally"). Note also that I<< the callback B<must> never die >>, so use
505	C<eval> if unsure.	493	C<eval> if unsure.
506		494
507	In the second form (another port given), the other port (C<$rcvport)	495	In the second form (another port given), the other port (C<$rcvport>)
508	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	496	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
509	"normal" kils nothing happens, while under all other conditions, the other	497	"normal" kils nothing happens, while under all other conditions, the other
510	port is killed with the same reason.	498	port is killed with the same reason.
511		499
512	The third form (kill self) is the same as the second form, except that	500	The third form (kill self) is the same as the second form, except that
513	C<$rvport> defaults to C<$SELF>.	501	C<$rvport> defaults to C<$SELF>.
514		502
515	In the last form (message), a message of the form C<@msg, @reason> will be	503	In the last form (message), a message of the form C<@msg, @reason> will be
516	C<snd>.	504	C<snd>.
517		505
		506	As a rule of thumb, monitoring requests should always monitor a port from
		507	a local port (or callback). The reason is that kill messages might get
		508	lost, just like any other message. Another less obvious reason is that
		509	even monitoring requests can get lost (for example, when the connection
		510	to the other node goes down permanently). When monitoring a port locally
		511	these problems do not exist.
		512
518	Example: call a given callback when C<$port> is killed.	513	Example: call a given callback when C<$port> is killed.
519		514
520	mon $port, sub { warn "port died because of <@_>\n" };	515	mon $port, sub { warn "port died because of <@_>\n" };
521		516
522	Example: kill ourselves when C<$port> is killed abnormally.	517	Example: kill ourselves when C<$port> is killed abnormally.
…		…
528	mon $port, $self => "restart";	523	mon $port, $self => "restart";
529		524
530	=cut	525	=cut
531		526
532	sub mon {	527	sub mon {
533	my ($noderef, $port) = split /#/, shift, 2;	528	my ($nodeid, $port) = split /#/, shift, 2;
534		529
535	my $node = $NODE{$noderef} \|\| add_node $noderef;	530	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
536		531
537	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	532	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
538		533
539	unless (ref $cb) {	534	unless (ref $cb) {
540	if (@_) {	535	if (@_) {
541	# send a kill info message	536	# send a kill info message
542	my (@msg) = @_;	537	my (@msg) = ($cb, @_);
543	$cb = sub { snd @msg, @_ };	538	$cb = sub { snd @msg, @_ };
544	} else {	539	} else {
545	# simply kill other port	540	# simply kill other port
546	my $port = $cb;	541	my $port = $cb;
547	$cb = sub { kil $port, @_ if @_ };	542	$cb = sub { kil $port, @_ if @_ };
…		…
560	is killed, the references will be freed.	555	is killed, the references will be freed.
561		556
562	Optionally returns a guard that will stop the monitoring.	557	Optionally returns a guard that will stop the monitoring.
563		558
564	This function is useful when you create e.g. timers or other watchers and	559	This function is useful when you create e.g. timers or other watchers and
565	want to free them when the port gets killed:	560	want to free them when the port gets killed (note the use of C<psub>):
566		561
567	$port->rcv (start => sub {	562	$port->rcv (start => sub {
568	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	563	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
569	undef $timer if 0.9 < rand;	564	undef $timer if 0.9 < rand;
570	});	565	});
571	});	566	});
572		567
573	=cut	568	=cut
…		…
578	#TODO: mon-less form?	573	#TODO: mon-less form?
579		574
580	mon $port, sub { 0 && @refs }	575	mon $port, sub { 0 && @refs }
581	}	576	}
582		577
583	=item lnk $port1, $port2
584
585	=item lnk $otherport
586
587	Link two ports. This is simply a shorthand for:
588
589	mon $port1, $port2;
590	mon $port2, $port1;
591
592	It means that if either one is killed abnormally, the other one gets
593	killed as well.
594
595	The one-argument form assumes that one port is C<$SELF>.
596
597	=cut
598
599	sub lnk {
600	my $port1 = shift;
601	my $port2 = @_ ? shift : $SELF \|\| Carp::croak 'lnk: called with one argument only, but $SELF not set,';
602
603	mon $port1, $port2;
604	mon $port2, $port1;
605	}
606
607	=item kil $port[, @reason]	578	=item kil $port[, @reason]
608		579
609	Kill the specified port with the given C<@reason>.	580	Kill the specified port with the given C<@reason>.
610		581
611	If no C<@reason> is specified, then the port is killed "normally" (linked	582	If no C<@reason> is specified, then the port is killed "normally" (ports
612	ports will not be kileld, or even notified).	583	monitoring other ports will not necessarily die because a port dies
		584	"normally").
613		585
614	Otherwise, linked ports get killed with the same reason (second form of	586	Otherwise, linked ports get killed with the same reason (second form of
615	C<mon>, see below).	587	C<mon>, see above).
616		588
617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	589	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
618	will be reported as reason C<< die => $@ >>.	590	will be reported as reason C<< die => $@ >>.
619		591
620	Transport/communication errors are reported as C<< transport_error =>	592	Transport/communication errors are reported as C<< transport_error =>
621	$message >>.	593	$message >>.
622		594
623	=back
624
625	=head1 NODE MESSAGES
626
627	Nodes understand the following messages sent to them. Many of them take
628	arguments called C<@reply>, which will simply be used to compose a reply
629	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
630	the remaining arguments are simply the message data.
631
632	While other messages exist, they are not public and subject to change.
633
634	=over 4
635
636	=cut	595	=cut
637		596
638	=item lookup => $name, @reply	597	=item $port = spawn $node, $initfunc[, @initdata]
639		598
640	Replies with the port ID of the specified well-known port, or C<undef>.	599	Creates a port on the node C<$node> (which can also be a port ID, in which
		600	case it's the node where that port resides).
641		601
642	=item devnull => ...	602	The port ID of the newly created port is returned immediately, and it is
		603	possible to immediately start sending messages or to monitor the port.
643		604
644	Generic data sink/CPU heat conversion.	605	After the port has been created, the init function is called on the remote
		606	node, in the same context as a C<rcv> callback. This function must be a
		607	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		608	specify a function in the main program, use C<::name>.
645		609
646	=item relay => $port, @msg	610	If the function doesn't exist, then the node tries to C<require>
		611	the package, then the package above the package and so on (e.g.
		612	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		613	exists or it runs out of package names.
647		614
648	Simply forwards the message to the given port.	615	The init function is then called with the newly-created port as context
		616	object (C<$SELF>) and the C<@initdata> values as arguments.
649		617
650	=item eval => $string[ @reply]	618	A common idiom is to pass a local port, immediately monitor the spawned
		619	port, and in the remote init function, immediately monitor the passed
		620	local port. This two-way monitoring ensures that both ports get cleaned up
		621	when there is a problem.
651		622
652	Evaluates the given string. If C<@reply> is given, then a message of the	623	Example: spawn a chat server port on C<$othernode>.
653	form C<@reply, $@, @evalres> is sent.
654		624
655	Example: crash another node.	625	# this node, executed from within a port context:
		626	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		627	mon $server;
656		628
657	snd $othernode, eval => "exit";	629	# init function on C<$othernode>
		630	sub connect {
		631	my ($srcport) = @_;
658		632
659	=item time => @reply	633	mon $srcport;
660		634
661	Replies the the current node time to C<@reply>.	635	rcv $SELF, sub {
		636	...
		637	};
		638	}
662		639
663	Example: tell the current node to send the current time to C<$myport> in a	640	=cut
664	C<timereply> message.
665		641
666	snd $NODE, time => $myport, timereply => 1, 2;	642	sub _spawn {
667	# => snd $myport, timereply => 1, 2, <time>	643	my $port = shift;
		644	my $init = shift;
		645
		646	local $SELF = "$NODE#$port";
		647	eval {
		648	&{ load_func $init }
		649	};
		650	_self_die if $@;
		651	}
		652
		653	sub spawn(@) {
		654	my ($nodeid, undef) = split /#/, shift, 2;
		655
		656	my $id = "$RUNIQ." . $ID++;
		657
		658	$_[0] =~ /::/
		659	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		660
		661	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
		662
		663	"$nodeid#$id"
		664	}
		665
		666	=item after $timeout, @msg
		667
		668	=item after $timeout, $callback
		669
		670	Either sends the given message, or call the given callback, after the
		671	specified number of seconds.
		672
		673	This is simply a utility function that comes in handy at times - the
		674	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		675	so it may go away in the future.
		676
		677	=cut
		678
		679	sub after($@) {
		680	my ($timeout, @action) = @_;
		681
		682	my $t; $t = AE::timer $timeout, 0, sub {
		683	undef $t;
		684	ref $action[0]
		685	? $action[0]()
		686	: snd @action;
		687	};
		688	}
668		689
669	=back	690	=back
670		691
671	=head1 AnyEvent::MP vs. Distributed Erlang	692	=head1 AnyEvent::MP vs. Distributed Erlang
672		693
…		…
682		703
683	Despite the similarities, there are also some important differences:	704	Despite the similarities, there are also some important differences:
684		705
685	=over 4	706	=over 4
686		707
687	=item * Node references contain the recipe on how to contact them.	708	=item * Node IDs are arbitrary strings in AEMP.
688		709
689	Erlang relies on special naming and DNS to work everywhere in the	710	Erlang relies on special naming and DNS to work everywhere in the same
690	same way. AEMP relies on each node knowing it's own address(es), with	711	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
691	convenience functionality.	712	configuration or DNS), but will otherwise discover other odes itself.
692		713
693	This means that AEMP requires a less tightly controlled environment at the	714	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
694	cost of longer node references and a slightly higher management overhead.	715	uses "local ports are like remote ports".
		716
		717	The failure modes for local ports are quite different (runtime errors
		718	only) then for remote ports - when a local port dies, you I<know> it dies,
		719	when a connection to another node dies, you know nothing about the other
		720	port.
		721
		722	Erlang pretends remote ports are as reliable as local ports, even when
		723	they are not.
		724
		725	AEMP encourages a "treat remote ports differently" philosophy, with local
		726	ports being the special case/exception, where transport errors cannot
		727	occur.
695		728
696	=item * Erlang uses processes and a mailbox, AEMP does not queue.	729	=item * Erlang uses processes and a mailbox, AEMP does not queue.
697		730
698	Erlang uses processes that selctively receive messages, and therefore	731	Erlang uses processes that selectively receive messages, and therefore
699	needs a queue. AEMP is event based, queuing messages would serve no useful	732	needs a queue. AEMP is event based, queuing messages would serve no
700	purpose.	733	useful purpose. For the same reason the pattern-matching abilities of
		734	AnyEvent::MP are more limited, as there is little need to be able to
		735	filter messages without dequeuing them.
701		736
702	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	737	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
703		738
704	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
705		740
706	Sending messages in Erlang is synchronous and blocks the process. AEMP	741	Sending messages in Erlang is synchronous and blocks the process (and
707	sends are immediate, connection establishment is handled in the	742	so does not need a queue that can overflow). AEMP sends are immediate,
708	background.	743	connection establishment is handled in the background.
709		744
710	=item * Erlang can silently lose messages, AEMP cannot.	745	=item * Erlang suffers from silent message loss, AEMP does not.
711		746
712	Erlang makes few guarantees on messages delivery - messages can get lost	747	Erlang makes few guarantees on messages delivery - messages can get lost
713	without any of the processes realising it (i.e. you send messages a, b,	748	without any of the processes realising it (i.e. you send messages a, b,
714	and c, and the other side only receives messages a and c).	749	and c, and the other side only receives messages a and c).
715		750
716	AEMP guarantees correct ordering, and the guarantee that there are no	751	AEMP guarantees correct ordering, and the guarantee that after one message
717	holes in the message sequence.	752	is lost, all following ones sent to the same port are lost as well, until
718		753	monitoring raises an error, so there are no silent "holes" in the message
719	=item * In Erlang, processes can be declared dead and later be found to be	754	sequence.
720	alive.
721
722	In Erlang it can happen that a monitored process is declared dead and
723	linked processes get killed, but later it turns out that the process is
724	still alive - and can receive messages.
725
726	In AEMP, when port monitoring detects a port as dead, then that port will
727	eventually be killed - it cannot happen that a node detects a port as dead
728	and then later sends messages to it, finding it is still alive.
729		755
730	=item * Erlang can send messages to the wrong port, AEMP does not.	756	=item * Erlang can send messages to the wrong port, AEMP does not.
731		757
732	In Erlang it is quite possible that a node that restarts reuses a process	758	In Erlang it is quite likely that a node that restarts reuses a process ID
733	ID known to other nodes for a completely different process, causing	759	known to other nodes for a completely different process, causing messages
734	messages destined for that process to end up in an unrelated process.	760	destined for that process to end up in an unrelated process.
735		761
736	AEMP never reuses port IDs, so old messages or old port IDs floating	762	AEMP never reuses port IDs, so old messages or old port IDs floating
737	around in the network will not be sent to an unrelated port.	763	around in the network will not be sent to an unrelated port.
738		764
739	=item * Erlang uses unprotected connections, AEMP uses secure	765	=item * Erlang uses unprotected connections, AEMP uses secure
740	authentication and can use TLS.	766	authentication and can use TLS.
741		767
742	AEMP can use a proven protocol - SSL/TLS - to protect connections and	768	AEMP can use a proven protocol - TLS - to protect connections and
743	securely authenticate nodes.	769	securely authenticate nodes.
744		770
745	=item * The AEMP protocol is optimised for both text-based and binary	771	=item * The AEMP protocol is optimised for both text-based and binary
746	communications.	772	communications.
747		773
748	The AEMP protocol, unlike the Erlang protocol, supports both	774	The AEMP protocol, unlike the Erlang protocol, supports both programming
749	language-independent text-only protocols (good for debugging) and binary,	775	language independent text-only protocols (good for debugging) and binary,
750	language-specific serialisers (e.g. Storable).	776	language-specific serialisers (e.g. Storable). By default, unless TLS is
		777	used, the protocol is actually completely text-based.
751		778
752	It has also been carefully designed to be implementable in other languages	779	It has also been carefully designed to be implementable in other languages
753	with a minimum of work while gracefully degrading fucntionality to make the	780	with a minimum of work while gracefully degrading functionality to make the
754	protocol simple.	781	protocol simple.
755		782
756	=item * AEMP has more flexible monitoring options than Erlang.	783	=item * AEMP has more flexible monitoring options than Erlang.
757		784
758	In Erlang, you can chose to receive I<all> exit signals as messages	785	In Erlang, you can chose to receive I<all> exit signals as messages
759	or I<none>, there is no in-between, so monitoring single processes is	786	or I<none>, there is no in-between, so monitoring single processes is
760	difficult to implement. Monitoring in AEMP is more flexible than in	787	difficult to implement. Monitoring in AEMP is more flexible than in
761	Erlang, as one can choose between automatic kill, exit message or callback	788	Erlang, as one can choose between automatic kill, exit message or callback
762	on a per-process basis.	789	on a per-process basis.
763		790
764	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.	791	=item * Erlang tries to hide remote/local connections, AEMP does not.
765		792
766	Monitoring in Erlang is not an indicator of process death/crashes,	793	Monitoring in Erlang is not an indicator of process death/crashes, in the
767	as linking is (except linking is unreliable in Erlang). In AEMP, the	794	same way as linking is (except linking is unreliable in Erlang).
768	semantics of monitoring and linking are identical, linking is simply	795
769	two-way monitoring with automatic kill.	796	In AEMP, you don't "look up" registered port names or send to named ports
		797	that might or might not be persistent. Instead, you normally spawn a port
		798	on the remote node. The init function monitors you, and you monitor the
		799	remote port. Since both monitors are local to the node, they are much more
		800	reliable (no need for C<spawn_link>).
		801
		802	This also saves round-trips and avoids sending messages to the wrong port
		803	(hard to do in Erlang).
770		804
771	=back	805	=back
772		806
		807	=head1 RATIONALE
		808
		809	=over 4
		810
		811	=item Why strings for port and node IDs, why not objects?
		812
		813	We considered "objects", but found that the actual number of methods
		814	that can be called are quite low. Since port and node IDs travel over
		815	the network frequently, the serialising/deserialising would add lots of
		816	overhead, as well as having to keep a proxy object everywhere.
		817
		818	Strings can easily be printed, easily serialised etc. and need no special
		819	procedures to be "valid".
		820
		821	And as a result, a miniport consists of a single closure stored in a
		822	global hash - it can't become much cheaper.
		823
		824	=item Why favour JSON, why not a real serialising format such as Storable?
		825
		826	In fact, any AnyEvent::MP node will happily accept Storable as framing
		827	format, but currently there is no way to make a node use Storable by
		828	default (although all nodes will accept it).
		829
		830	The default framing protocol is JSON because a) JSON::XS is many times
		831	faster for small messages and b) most importantly, after years of
		832	experience we found that object serialisation is causing more problems
		833	than it solves: Just like function calls, objects simply do not travel
		834	easily over the network, mostly because they will always be a copy, so you
		835	always have to re-think your design.
		836
		837	Keeping your messages simple, concentrating on data structures rather than
		838	objects, will keep your messages clean, tidy and efficient.
		839
		840	=back
		841
773	=head1 SEE ALSO	842	=head1 SEE ALSO
		843
		844	L<AnyEvent::MP::Intro> - a gentle introduction.
		845
		846	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		847
		848	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		849	your applications.
774		850
775	L<AnyEvent>.	851	L<AnyEvent>.
776		852
777	=head1 AUTHOR	853	=head1 AUTHOR
778		854

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs. Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC