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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
13	$SELF # receiving/own port id in rcv callbacks	12	$SELF # receiving/own port id in rcv callbacks
14		13
		14	# initialise the node so it can send/receive messages
		15	configure;
		16
15	# ports are message endpoints	17	# ports are message destinations
16		18
17	# sending messages	19	# sending messages
18	snd $port, type => data...;	20	snd $port, type => data...;
19	snd $port, @msg;	21	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
21		23
22	# miniports	24	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
24		26
25	# full ports	27	# creating/using ports, tagged message matching
26	my $port = port;	28	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
30		31
31	# remote ports	32	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
33
34	# more, smarter, matches (_any_ is exported by this module)
35	rcv $port, [child_died => $pid] => sub { ...
36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
37		34
38	# monitoring	35	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	36	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
42		39
43	=head1 CURRENT STATUS	40	=head1 CURRENT STATUS
44		41
		42	bin/aemp - stable.
45	AnyEvent::MP - stable API, should work	43	AnyEvent::MP - stable API, should work.
46	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - explains most concepts.
47	AnyEvent::MP::Kernel - WIP
48	AnyEvent::MP::Transport - mostly stable	45	AnyEvent::MP::Kernel - mostly stable.
		46	AnyEvent::MP::Global - stable API, protocol not yet final.
49		47
50	stay tuned.	48	stay tuned.
51		49
52	=head1 DESCRIPTION	50	=head1 DESCRIPTION
53		51
54	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
55		53
56	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
57	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
58		56
59	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>
60	manual page.	58	manual page and the examples under F<eg/>.
61
62	At the moment, this module family is severly broken and underdocumented,
63	so do not use. This was uploaded mainly to reserve the CPAN namespace -
64	stay tuned!
65		59
66	=head1 CONCEPTS	60	=head1 CONCEPTS
67		61
68	=over 4	62	=over 4
69		63
70	=item port	64	=item port
71		65
72	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).
73		67
74	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
75	messages. All C<rcv> handlers will receive messages they match, messages	69	some messages. Messages send to ports will not be queued, regardless of
76	will not be queued.	70	anything was listening for them or not.
77		71
78	=item port id - C<noderef#portname>	72	=item port ID - C<nodeid#portname>
79		73
80	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
81	separator, and a port name (a printable string of unspecified format). An	75	separator, and a port name (a printable string of unspecified format).
82	exception is the the node port, whose ID is identical to its node
83	reference.
84		76
85	=item node	77	=item node
86		78
87	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,
88	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
89	create new ports, among other things.	81	ports.
90		82
91	Nodes are either private (single-process only), slaves (connected to a	83	Nodes are either public (have one or more listening ports) or private
92	master node only) or public nodes (connectable from unrelated nodes).	84	(no listening ports). Private nodes cannot talk to other private nodes
		85	currently.
93		86
94	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	87	=item node ID - C<[a-za-Z0-9_\-.:]+>
95		88
96	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
97	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
98	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.
99		93
100	This recipe is simply a comma-separated list of C<address:port> pairs (for	94	=item binds - C<ip:port>
101	TCP/IP, other protocols might look different).
102		95
103	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
104	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.
105		100
106	Before using an unresolved node reference in a message you first have to	101	=item seeds - C<host:port>
107	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.
108		115
109	=back	116	=back
110		117
111	=head1 VARIABLES/FUNCTIONS	118	=head1 VARIABLES/FUNCTIONS
112		119
…		…
127	use base "Exporter";	134	use base "Exporter";
128		135
129	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
130		137
131	our @EXPORT = qw(	138	our @EXPORT = qw(
132	NODE $NODE *SELF node_of _any_	139	NODE $NODE *SELF node_of after
133	resolve_node initialise_node	140	configure
134	snd rcv mon kil reg psub spawn	141	snd rcv mon mon_guard kil reg psub spawn
135	port	142	port
136	);	143	);
137		144
138	our $SELF;	145	our $SELF;
139		146
…		…
143	kil $SELF, die => $msg;	150	kil $SELF, die => $msg;
144	}	151	}
145		152
146	=item $thisnode = NODE / $NODE	153	=item $thisnode = NODE / $NODE
147		154
148	The C<NODE> function returns, and the C<$NODE> variable contains	155	The C<NODE> function returns, and the C<$NODE> variable contains, the node
149	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
150	to C<become_public> or C<become_slave>, after which all local port	157	a call to C<configure>.
151	identifiers become invalid.
152		158
153	=item $noderef = node_of $port	159	=item $nodeid = node_of $port
154		160
155	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.
156		162
157	=item initialise_node $noderef, $seednode, $seednode...	163	=item configure $profile, key => value...
158		164
159	=item initialise_node "slave/", $master, $master...	165	=item configure key => value...
160		166
161	Before a node can talk to other nodes on the network it has to initialise	167	Before a node can talk to other nodes on the network (i.e. enter
162	itself - the minimum a node needs to know is it's own name, and optionally	168	"distributed mode") it has to configure itself - the minimum a node needs
163	it should know the noderefs of some other nodes in the network.	169	to know is its own name, and optionally it should know the addresses of
		170	some other nodes in the network to discover other nodes.
164		171
165	This function initialises a node - it must be called exactly once (or	172	This function configures a node - it must be called exactly once (or
166	never) before calling other AnyEvent::MP functions.	173	never) before calling other AnyEvent::MP functions.
167		174
168	All arguments are noderefs, which can be either resolved or unresolved.
169
170	There are two types of networked nodes, public nodes and slave nodes:
171
172	=over 4	175	=over 4
173		176
174	=item public nodes	177	=item step 1, gathering configuration from profiles
175		178
176	For public nodes, C<$noderef> must either be a (possibly unresolved)	179	The function first looks up a profile in the aemp configuration (see the
177	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
178	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.
179		183
180	Afterwards, the node will bind itself on all endpoints and try to connect	184	The profile data is then gathered as follows:
181	to all additional C<$seednodes> that are specified. Seednodes are optional
182	and can be used to quickly bootstrap the node into an existing network.
183		185
184	=item slave nodes	186	First, all remaining key => value pairs (all of which are conveniently
		187	undocumented at the moment) will be interpreted as configuration
		188	data. Then they will be overwritten by any values specified in the global
		189	default configuration (see the F<aemp> utility), then the chain of
		190	profiles chosen by the profile name (and any C<parent> attributes).
185		191
186	When the C<$noderef> is the special string C<slave/>, then the node will	192	That means that the values specified in the profile have highest priority
187	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,
188	route most of their traffic to the master node that they attach to.	194	and can only be used to specify defaults.
189		195
190	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
191	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
192	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.
193		217
194	=back	218	=back
195		219
196	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.
197	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.
198	server.
199		222
200	Example: become a public node listening on the default node.	223	configure
201		224
202	initialise_node;	225	Example: become an anonymous node. This form is often used for commandline
		226	clients.
203		227
204	Example: become a public node, and try to contact some well-known master	228	configure nodeid => "anon/";
205	servers to become part of the network.
206		229
207	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).
208		233
209	Example: become a public node listening on port C<4041>.	234	# use the aemp commandline utility
		235	# aemp profile seed nodeid anon/ binds '*:4040'
210		236
211	initialise_node 4041;	237	# then use it
		238	configure profile => "seed";
212		239
213	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
214		242
215	initialise_node "locahost:4044";	243	# or provide a nicer-to-remember nodeid
216		244	# aemp run profile seed nodeid "$(hostname)"
217	Example: become a slave node to any of the specified master servers.
218
219	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
220
221	=item $cv = resolve_node $noderef
222
223	Takes an unresolved node reference that may contain hostnames and
224	abbreviated IDs, resolves all of them and returns a resolved node
225	reference.
226
227	In addition to C<address:port> pairs allowed in resolved noderefs, the
228	following forms are supported:
229
230	=over 4
231
232	=item the empty string
233
234	An empty-string component gets resolved as if the default port (4040) was
235	specified.
236
237	=item naked port numbers (e.g. C<1234>)
238
239	These are resolved by prepending the local nodename and a colon, to be
240	further resolved.
241
242	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
243
244	These are resolved by using AnyEvent::DNS to resolve them, optionally
245	looking up SRV records for the C<aemp=4040> port, if no port was
246	specified.
247
248	=back
249		245
250	=item $SELF	246	=item $SELF
251		247
252	Contains the current port id while executing C<rcv> callbacks or C<psub>	248	Contains the current port id while executing C<rcv> callbacks or C<psub>
253	blocks.	249	blocks.
254		250
255	=item SELF, %SELF, @SELF...	251	=item *SELF, SELF, %SELF, @SELF...
256		252
257	Due to some quirks in how perl exports variables, it is impossible to	253	Due to some quirks in how perl exports variables, it is impossible to
258	just export C<$SELF>, all the symbols called C<SELF> are exported by this	254	just export C<$SELF>, all the symbols named C<SELF> are exported by this
259	module, but only C<$SELF> is currently used.	255	module, but only C<$SELF> is currently used.
260		256
261	=item snd $port, type => @data	257	=item snd $port, type => @data
262		258
263	=item snd $port, @msg	259	=item snd $port, @msg
264		260
265	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
266	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.
267	stringifies a sa port ID (such as a port object :).
268		263
269	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
270	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
271	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.
272		268
273	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
274	function: modifying any argument is not allowed and can cause many	270	function: modifying any argument (or values referenced by them) is
275	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.
276		275
277	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
278	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
279	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
280	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
281	node, anything can be passed.	280	node, anything can be passed. Best rely only on the common denominator of
		281	these.
282		282
283	=item $local_port = port	283	=item $local_port = port
284		284
285	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
286	matching port ("full port") or a single-callback port ("miniport"),	286	no callbacks set and will throw an error when it receives messages.
287	depending on how C<rcv> callbacks are bound to the object.
288		287
289	=item $port = port { my @msg = @_; $finished }	288	=item $local_port = port { my @msg = @_ }
290		289
291	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
292	matching behind it, and returns its ID. Semantically the same as creating
293	a port and calling C<rcv $port, $callback> on it.	291	creating a port and calling C<rcv $port, $callback> on it.
294		292
295	The block will be called for every message received on the port. When the	293	The block will be called for every message received on the port, with the
296	callback returns a true value its job is considered "done" and the port	294	global variable C<$SELF> set to the port ID. Runtime errors will cause the
297	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.
298		297
299	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:
300	be passed to the callback.
301		299
302	If you need the local port id in the callback, this works nicely:	300	my $port = port {
303		301	my @msg = @_;
304	my $port; $port = port {	302	...
305	snd $otherport, reply => $port;	303	kil $SELF;
306	};	304	};
307		305
308	=cut	306	=cut
309		307
310	sub rcv($@);	308	sub rcv($@);
		309
		310	sub _kilme {
		311	die "received message on port without callback";
		312	}
311		313
312	sub port(;&) {	314	sub port(;&) {
313	my $id = "$UNIQ." . $ID++;	315	my $id = "$UNIQ." . $ID++;
314	my $port = "$NODE#$id";	316	my $port = "$NODE#$id";
315		317
316	if (@_) {	318	rcv $port, shift \|\| \&_kilme;
317	rcv $port, shift;
318	} else {
319	$PORT{$id} = sub { }; # nop
320	}
321		319
322	$port	320	$port
323	}	321	}
324		322
325	=item reg $port, $name
326
327	=item reg $name
328
329	Registers the given port (or C<$SELF><<< if missing) under the name
330	C<$name>. If the name already exists it is replaced.
331
332	A port can only be registered under one well known name.
333
334	A port automatically becomes unregistered when it is killed.
335
336	=cut
337
338	sub reg(@) {
339	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
340
341	$REG{$_[0]} = $port;
342	}
343
344	=item rcv $port, $callback->(@msg)	323	=item rcv $local_port, $callback->(@msg)
345		324
346	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
347	one if required).	326	remove the default callback: use C<sub { }> to disable it, or better
348		327	C<kil> the port when it is no longer needed.
349	=item rcv $port, tagstring => $callback->(@msg), ...
350
351	=item rcv $port, $smartmatch => $callback->(@msg), ...
352
353	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
354
355	Register callbacks to be called on matching messages on the given full
356	port (after converting it to one if required) and return the port.
357
358	The callback has to return a true value when its work is done, after
359	which is will be removed, or a false value in which case it will stay
360	registered.
361		328
362	The global C<$SELF> (exported by this module) contains C<$port> while	329	The global C<$SELF> (exported by this module) contains C<$port> while
363	executing the callback.	330	executing the callback. Runtime errors during callback execution will
		331	result in the port being C<kil>ed.
364		332
365	Runtime errors during callback execution will result in the port being	333	The default callback received all messages not matched by a more specific
366	C<kil>ed.	334	C<tag> match.
367		335
368	If the match is an array reference, then it will be matched against the	336	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
369	first elements of the message, otherwise only the first element is being
370	matched.
371		337
372	Any element in the match that is specified as C<_any_> (a function	338	Register (or replace) callbacks to be called on messages starting with the
373	exported by this module) matches any single element of the message.	339	given tag on the given port (and return the port), or unregister it (when
		340	C<$callback> is C<$undef> or missing). There can only be one callback
		341	registered for each tag.
374		342
375	While not required, it is highly recommended that the first matching	343	The original message will be passed to the callback, after the first
376	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
377	also the most efficient match (by far).	345	environment as the default callback (see above).
378		346
379	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.
380		348
381	my $port = rcv port,	349	my $port = rcv port,
382	msg1 => sub { ...; 0 },	350	msg1 => sub { ... },
383	msg2 => sub { ...; 0 },	351	msg2 => sub { ... },
384	;	352	;
385		353
386	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
387	in one go:	355	in one go:
388		356
389	snd $otherport, reply =>	357	snd $otherport, reply =>
390	rcv port,	358	rcv port,
391	msg1 => sub { ...; 0 },	359	msg1 => sub { ... },
392	...	360	...
393	;	361	;
394		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, $otherport;
		370	};
		371
395	=cut	372	=cut
396		373
397	sub rcv($@) {	374	sub rcv($@) {
398	my $port = shift;	375	my $port = shift;
399	my ($noderef, $portid) = split /#/, $port, 2;	376	my ($nodeid, $portid) = split /#/, $port, 2;
400		377
401	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	378	$NODE{$nodeid} == $NODE{""}
402	or Carp::croak "$port: rcv can only be called on local ports, caught";	379	or Carp::croak "$port: rcv can only be called on local ports, caught";
403		380
404	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 {
405	my $cb = shift;	389	my $cb = shift;
406	delete $PORT_DATA{$portid};
407	$PORT{$portid} = sub {	390	$PORT{$portid} = sub {
408	local $SELF = $port;	391	local $SELF = $port;
409	eval {	392	eval { &$cb }; _self_die if $@;
410	&$cb	393	};
411	and kil $port;
412	};	394	}
413	_self_die if $@;	395	} elsif (defined $_[0]) {
414	};
415	} else {
416	my $self = $PORT_DATA{$portid} \|\|= do {	396	my $self = $PORT_DATA{$portid} \|\|= do {
417	my $self = bless {	397	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
418	id => $port,
419	}, "AnyEvent::MP::Port";
420		398
421	$PORT{$portid} = sub {	399	$PORT{$portid} = sub {
422	local $SELF = $port;	400	local $SELF = $port;
423		401
424	eval {
425	for (@{ $self->{rc0}{$_[0]} }) {	402	if (my $cb = $self->[1]{$_[0]}) {
426	$_ && &{$_->[0]}	403	shift;
427	&& undef $_;	404	eval { &$cb }; _self_die if $@;
428	}	405	} else {
429
430	for (@{ $self->{rcv}{$_[0]} }) {
431	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
432	&& &{$_->[0]}	406	&{ $self->[0] };
433	&& undef $_;
434	}
435
436	for (@{ $self->{any} }) {
437	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
438	&& &{$_->[0]}
439	&& undef $_;
440	}	407	}
441	};	408	};
442	_self_die if $@;	409
		410	$self
443	};	411	};
444		412
445	$self
446	};
447
448	"AnyEvent::MP::Port" eq ref $self	413	"AnyEvent::MP::Port" eq ref $self
449	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
450		415
451	while (@_) {
452	my ($match, $cb) = splice @_, 0, 2;	416	my ($tag, $cb) = splice @_, 0, 2;
453		417
454	if (!ref $match) {	418	if (defined $cb) {
455	push @{ $self->{rc0}{$match} }, [$cb];	419	$self->[1]{$tag} = $cb;
456	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
457	my ($type, @match) = @$match;
458	@match
459	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
460	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
461	} else {	420	} else {
462	push @{ $self->{any} }, [$cb, $match];	421	delete $self->[1]{$tag};
463	}	422	}
464	}	423	}
465	}	424	}
466		425
467	$port	426	$port
…		…
503	$res	462	$res
504	}	463	}
505	}	464	}
506	}	465	}
507		466
508	=item $guard = mon $port, $cb->(@reason)	467	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
509		468
510	=item $guard = mon $port, $rcvport	469	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
511		470
512	=item $guard = mon $port	471	=item $guard = mon $port # kill $SELF when $port dies
513		472
514	=item $guard = mon $port, $rcvport, @msg	473	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
515		474
516	Monitor the given port and do something when the port is killed or	475	Monitor the given port and do something when the port is killed or
517	messages to it were lost, and optionally return a guard that can be used	476	messages to it were lost, and optionally return a guard that can be used
518	to stop monitoring again.	477	to stop monitoring again.
519		478
520	C<mon> effectively guarantees that, in the absence of hardware failures,	479	C<mon> effectively guarantees that, in the absence of hardware failures,
521	that after starting the monitor, either all messages sent to the port	480	after starting the monitor, either all messages sent to the port will
522	will arrive, or the monitoring action will be invoked after possible	481	arrive, or the monitoring action will be invoked after possible message
523	message loss has been detected. No messages will be lost "in between"	482	loss has been detected. No messages will be lost "in between" (after
524	(after the first lost message no further messages will be received by the	483	the first lost message no further messages will be received by the
525	port). After the monitoring action was invoked, further messages might get	484	port). After the monitoring action was invoked, further messages might get
526	delivered again.	485	delivered again.
		486
		487	Note that monitoring-actions are one-shot: once messages are lost (and a
		488	monitoring alert was raised), they are removed and will not trigger again.
527		489
528	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
529	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
530	"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
531	C<eval> if unsure.	493	C<eval> if unsure.
532		494
533	In the second form (another port given), the other port (C<$rcvport>)	495	In the second form (another port given), the other port (C<$rcvport>)
534	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	496	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
535	"normal" kils nothing happens, while under all other conditions, the other	497	"normal" kils nothing happens, while under all other conditions, the other
536	port is killed with the same reason.	498	port is killed with the same reason.
537		499
538	The third form (kill self) is the same as the second form, except that	500	The third form (kill self) is the same as the second form, except that
539	C<$rvport> defaults to C<$SELF>.	501	C<$rvport> defaults to C<$SELF>.
…		…
542	C<snd>.	504	C<snd>.
543		505
544	As a rule of thumb, monitoring requests should always monitor a port from	506	As a rule of thumb, monitoring requests should always monitor a port from
545	a local port (or callback). The reason is that kill messages might get	507	a local port (or callback). The reason is that kill messages might get
546	lost, just like any other message. Another less obvious reason is that	508	lost, just like any other message. Another less obvious reason is that
547	even monitoring requests can get lost (for exmaple, when the connection	509	even monitoring requests can get lost (for example, when the connection
548	to the other node goes down permanently). When monitoring a port locally	510	to the other node goes down permanently). When monitoring a port locally
549	these problems do not exist.	511	these problems do not exist.
550		512
551	Example: call a given callback when C<$port> is killed.	513	Example: call a given callback when C<$port> is killed.
552		514
…		…
561	mon $port, $self => "restart";	523	mon $port, $self => "restart";
562		524
563	=cut	525	=cut
564		526
565	sub mon {	527	sub mon {
566	my ($noderef, $port) = split /#/, shift, 2;	528	my ($nodeid, $port) = split /#/, shift, 2;
567		529
568	my $node = $NODE{$noderef} \|\| add_node $noderef;	530	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
569		531
570	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	532	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
571		533
572	unless (ref $cb) {	534	unless (ref $cb) {
573	if (@_) {	535	if (@_) {
…		…
593	is killed, the references will be freed.	555	is killed, the references will be freed.
594		556
595	Optionally returns a guard that will stop the monitoring.	557	Optionally returns a guard that will stop the monitoring.
596		558
597	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
598	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>):
599		561
600	$port->rcv (start => sub {	562	$port->rcv (start => sub {
601	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	563	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
602	undef $timer if 0.9 < rand;	564	undef $timer if 0.9 < rand;
603	});	565	});
604	});	566	});
605		567
606	=cut	568	=cut
…		…
615		577
616	=item kil $port[, @reason]	578	=item kil $port[, @reason]
617		579
618	Kill the specified port with the given C<@reason>.	580	Kill the specified port with the given C<@reason>.
619		581
620	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
621	ports will not be kileld, or even notified).	583	monitoring other ports will not necessarily die because a port dies
		584	"normally").
622		585
623	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
624	C<mon>, see below).	587	C<mon>, see above).
625		588
626	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
627	will be reported as reason C<< die => $@ >>.	590	will be reported as reason C<< die => $@ >>.
628		591
629	Transport/communication errors are reported as C<< transport_error =>	592	Transport/communication errors are reported as C<< transport_error =>
…		…
634	=item $port = spawn $node, $initfunc[, @initdata]	597	=item $port = spawn $node, $initfunc[, @initdata]
635		598
636	Creates a port on the node C<$node> (which can also be a port ID, in which	599	Creates a port on the node C<$node> (which can also be a port ID, in which
637	case it's the node where that port resides).	600	case it's the node where that port resides).
638		601
639	The port ID of the newly created port is return immediately, and it is	602	The port ID of the newly created port is returned immediately, and it is
640	permissible to immediately start sending messages or monitor the port.	603	possible to immediately start sending messages or to monitor the port.
641		604
642	After the port has been created, the init function is	605	After the port has been created, the init function is called on the remote
643	called. This function must be a fully-qualified function name	606	node, in the same context as a C<rcv> callback. This function must be a
644	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	607	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
645	program, use C<::name>.	608	specify a function in the main program, use C<::name>.
646		609
647	If the function doesn't exist, then the node tries to C<require>	610	If the function doesn't exist, then the node tries to C<require>
648	the package, then the package above the package and so on (e.g.	611	the package, then the package above the package and so on (e.g.
649	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	612	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
650	exists or it runs out of package names.	613	exists or it runs out of package names.
651		614
652	The init function is then called with the newly-created port as context	615	The init function is then called with the newly-created port as context
653	object (C<$SELF>) and the C<@initdata> values as arguments.	616	object (C<$SELF>) and the C<@initdata> values as arguments.
654		617
655	A common idiom is to pass your own port, monitor the spawned port, and	618	A common idiom is to pass a local port, immediately monitor the spawned
656	in the init function, monitor the original port. This two-way monitoring	619	port, and in the remote init function, immediately monitor the passed
657	ensures that both ports get cleaned up when there is a problem.	620	local port. This two-way monitoring ensures that both ports get cleaned up
		621	when there is a problem.
658		622
659	Example: spawn a chat server port on C<$othernode>.	623	Example: spawn a chat server port on C<$othernode>.
660		624
661	# this node, executed from within a port context:	625	# this node, executed from within a port context:
662	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	626	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
685	};	649	};
686	_self_die if $@;	650	_self_die if $@;
687	}	651	}
688		652
689	sub spawn(@) {	653	sub spawn(@) {
690	my ($noderef, undef) = split /#/, shift, 2;	654	my ($nodeid, undef) = split /#/, shift, 2;
691		655
692	my $id = "$RUNIQ." . $ID++;	656	my $id = "$RUNIQ." . $ID++;
693		657
694	$_[0] =~ /::/	658	$_[0] =~ /::/
695	or Carp::croak "spawn init function must be a fully-qualified name, caught";	659	or Carp::croak "spawn init function must be a fully-qualified name, caught";
696		660
697	($NODE{$noderef} \|\| add_node $noderef)	661	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
698	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
699		662
700	"$noderef#$id"	663	"$nodeid#$id"
701	}	664	}
702		665
703	=back	666	=item after $timeout, @msg
704		667
705	=head1 NODE MESSAGES	668	=item after $timeout, $callback
706		669
707	Nodes understand the following messages sent to them. Many of them take	670	Either sends the given message, or call the given callback, after the
708	arguments called C<@reply>, which will simply be used to compose a reply	671	specified number of seconds.
709	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
710	the remaining arguments are simply the message data.
711		672
712	While other messages exist, they are not public and subject to change.	673	This is simply a utility function that comes in handy at times - the
		674	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		675	so it may go away in the future.
713		676
714	=over 4
715
716	=cut	677	=cut
717		678
718	=item lookup => $name, @reply	679	sub after($@) {
		680	my ($timeout, @action) = @_;
719		681
720	Replies with the port ID of the specified well-known port, or C<undef>.	682	my $t; $t = AE::timer $timeout, 0, sub {
721		683	undef $t;
722	=item devnull => ...	684	ref $action[0]
723		685	? $action[0]()
724	Generic data sink/CPU heat conversion.	686	: snd @action;
725		687	};
726	=item relay => $port, @msg	688	}
727
728	Simply forwards the message to the given port.
729
730	=item eval => $string[ @reply]
731
732	Evaluates the given string. If C<@reply> is given, then a message of the
733	form C<@reply, $@, @evalres> is sent.
734
735	Example: crash another node.
736
737	snd $othernode, eval => "exit";
738
739	=item time => @reply
740
741	Replies the the current node time to C<@reply>.
742
743	Example: tell the current node to send the current time to C<$myport> in a
744	C<timereply> message.
745
746	snd $NODE, time => $myport, timereply => 1, 2;
747	# => snd $myport, timereply => 1, 2, <time>
748		689
749	=back	690	=back
750		691
751	=head1 AnyEvent::MP vs. Distributed Erlang	692	=head1 AnyEvent::MP vs. Distributed Erlang
752		693
…		…
762		703
763	Despite the similarities, there are also some important differences:	704	Despite the similarities, there are also some important differences:
764		705
765	=over 4	706	=over 4
766		707
767	=item * Node references contain the recipe on how to contact them.	708	=item * Node IDs are arbitrary strings in AEMP.
768		709
769	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
770	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
771	convenience functionality.	712	configuration or DNS), but will otherwise discover other odes itself.
772		713
773	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
774	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.
775		728
776	=item * Erlang uses processes and a mailbox, AEMP does not queue.	729	=item * Erlang uses processes and a mailbox, AEMP does not queue.
777		730
778	Erlang uses processes that selctively receive messages, and therefore	731	Erlang uses processes that selectively receive messages, and therefore
779	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
780	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.
781		736
782	(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).
783		738
784	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
785		740
786	Sending messages in Erlang is synchronous and blocks the process. AEMP	741	Sending messages in Erlang is synchronous and blocks the process (and
787	sends are immediate, connection establishment is handled in the	742	so does not need a queue that can overflow). AEMP sends are immediate,
788	background.	743	connection establishment is handled in the background.
789		744
790	=item * Erlang can silently lose messages, AEMP cannot.	745	=item * Erlang suffers from silent message loss, AEMP does not.
791		746
792	Erlang makes few guarantees on messages delivery - messages can get lost	747	Erlang makes few guarantees on messages delivery - messages can get lost
793	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,
794	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).
795		750
796	AEMP guarantees correct ordering, and the guarantee that there are no	751	AEMP guarantees correct ordering, and the guarantee that after one message
797	holes in the message sequence.	752	is lost, all following ones sent to the same port are lost as well, until
798		753	monitoring raises an error, so there are no silent "holes" in the message
799	=item * In Erlang, processes can be declared dead and later be found to be	754	sequence.
800	alive.
801
802	In Erlang it can happen that a monitored process is declared dead and
803	linked processes get killed, but later it turns out that the process is
804	still alive - and can receive messages.
805
806	In AEMP, when port monitoring detects a port as dead, then that port will
807	eventually be killed - it cannot happen that a node detects a port as dead
808	and then later sends messages to it, finding it is still alive.
809		755
810	=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.
811		757
812	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
813	ID known to other nodes for a completely different process, causing	759	known to other nodes for a completely different process, causing messages
814	messages destined for that process to end up in an unrelated process.	760	destined for that process to end up in an unrelated process.
815		761
816	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
817	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.
818		764
819	=item * Erlang uses unprotected connections, AEMP uses secure	765	=item * Erlang uses unprotected connections, AEMP uses secure
820	authentication and can use TLS.	766	authentication and can use TLS.
821		767
822	AEMP can use a proven protocol - SSL/TLS - to protect connections and	768	AEMP can use a proven protocol - TLS - to protect connections and
823	securely authenticate nodes.	769	securely authenticate nodes.
824		770
825	=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
826	communications.	772	communications.
827		773
828	The AEMP protocol, unlike the Erlang protocol, supports both	774	The AEMP protocol, unlike the Erlang protocol, supports both programming
829	language-independent text-only protocols (good for debugging) and binary,	775	language independent text-only protocols (good for debugging) and binary,
830	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.
831		778
832	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
833	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
834	protocol simple.	781	protocol simple.
835		782
836	=item * AEMP has more flexible monitoring options than Erlang.	783	=item * AEMP has more flexible monitoring options than Erlang.
837		784
838	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
…		…
841	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
842	on a per-process basis.	789	on a per-process basis.
843		790
844	=item * Erlang tries to hide remote/local connections, AEMP does not.	791	=item * Erlang tries to hide remote/local connections, AEMP does not.
845		792
846	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
847	as linking is (except linking is unreliable in Erlang).	794	same way as linking is (except linking is unreliable in Erlang).
848		795
849	In AEMP, you don't "look up" registered port names or send to named ports	796	In AEMP, you don't "look up" registered port names or send to named ports
850	that might or might not be persistent. Instead, you normally spawn a port	797	that might or might not be persistent. Instead, you normally spawn a port
851	on the remote node. The init function monitors the you, and you monitor	798	on the remote node. The init function monitors you, and you monitor the
852	the remote port. Since both monitors are local to the node, they are much	799	remote port. Since both monitors are local to the node, they are much more
853	more reliable.	800	reliable (no need for C<spawn_link>).
854		801
855	This also saves round-trips and avoids sending messages to the wrong port	802	This also saves round-trips and avoids sending messages to the wrong port
856	(hard to do in Erlang).	803	(hard to do in Erlang).
857		804
858	=back	805	=back
859		806
860	=head1 RATIONALE	807	=head1 RATIONALE
861		808
862	=over 4	809	=over 4
863		810
864	=item Why strings for ports and noderefs, why not objects?	811	=item Why strings for port and node IDs, why not objects?
865		812
866	We considered "objects", but found that the actual number of methods	813	We considered "objects", but found that the actual number of methods
867	thatc an be called are very low. Since port IDs and noderefs travel over	814	that can be called are quite low. Since port and node IDs travel over
868	the network frequently, the serialising/deserialising would add lots of	815	the network frequently, the serialising/deserialising would add lots of
869	overhead, as well as having to keep a proxy object.	816	overhead, as well as having to keep a proxy object everywhere.
870		817
871	Strings can easily be printed, easily serialised etc. and need no special	818	Strings can easily be printed, easily serialised etc. and need no special
872	procedures to be "valid".	819	procedures to be "valid".
873		820
874	And a a miniport consists of a single closure stored in a global hash - it	821	And as a result, a miniport consists of a single closure stored in a
875	can't become much cheaper.	822	global hash - it can't become much cheaper.
876		823
877	=item Why favour JSON, why not real serialising format such as Storable?	824	=item Why favour JSON, why not a real serialising format such as Storable?
878		825
879	In fact, any AnyEvent::MP node will happily accept Storable as framing	826	In fact, any AnyEvent::MP node will happily accept Storable as framing
880	format, but currently there is no way to make a node use Storable by	827	format, but currently there is no way to make a node use Storable by
881	default.	828	default (although all nodes will accept it).
882		829
883	The default framing protocol is JSON because a) JSON::XS is many times	830	The default framing protocol is JSON because a) JSON::XS is many times
884	faster for small messages and b) most importantly, after years of	831	faster for small messages and b) most importantly, after years of
885	experience we found that object serialisation is causing more problems	832	experience we found that object serialisation is causing more problems
886	than it gains: Just like function calls, objects simply do not travel	833	than it solves: Just like function calls, objects simply do not travel
887	easily over the network, mostly because they will always be a copy, so you	834	easily over the network, mostly because they will always be a copy, so you
888	always have to re-think your design.	835	always have to re-think your design.
889		836
890	Keeping your messages simple, concentrating on data structures rather than	837	Keeping your messages simple, concentrating on data structures rather than
891	objects, will keep your messages clean, tidy and efficient.	838	objects, will keep your messages clean, tidy and efficient.
892		839
893	=back	840	=back
894		841
895	=head1 SEE ALSO	842	=head1 SEE ALSO
896		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.
		850
897	L<AnyEvent>.	851	L<AnyEvent>.
898		852
899	=head1 AUTHOR	853	=head1 AUTHOR
900		854
901	Marc Lehmann <schmorp@schmorp.de>	855	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.47 by root, Thu Aug 13 01:57:10 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 1.47 by root, Thu Aug 13 01:57:10 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC