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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.40 by root, Sat Aug 8 00:22:16 2009 UTC vs.
Revision 1.67 by root, Fri Aug 28 22:21:53 2009 UTC

…		…
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
13	$SELF # receiving/own port id in rcv callbacks	13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node;
14		17
15	# ports are message endpoints	18	# ports are message endpoints
16		19
17	# sending messages	20	# sending messages
18	snd $port, type => data...;	21	snd $port, type => data...;
19	snd $port, @msg;	22	snd $port, @msg;
20	snd @msg_with_first_element_being_a_port;	23	snd @msg_with_first_element_being_a_port;
21		24
22	# miniports	25	# creating/using ports, the simple way
23	my $miniport = port { my @msg = @_; 0 };	26	my $simple_port = port { my @msg = @_; 0 };
24		27
25	# full ports	28	# creating/using ports, tagged message matching
26	my $port = port;	29	my $port = port;
27	rcv $port, smartmatch => $cb->(@msg);
28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
29	rcv $port, pong => sub { warn "pong received\n"; 0 };	31	rcv $port, pong => sub { warn "pong received\n"; 0 };
30		32
31	# remote ports	33	# create a port on another node
32	my $port = spawn $node, $initfunc, @initdata;	34	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		35
38	# monitoring	36	# monitoring
39	mon $port, $cb->(@msg) # callback is invoked on death	37	mon $port, $cb->(@msg) # callback is invoked on death
40	mon $port, $otherport # kill otherport on abnormal death	38	mon $port, $otherport # kill otherport on abnormal death
41	mon $port, $otherport, @msg # send message on death	39	mon $port, $otherport, @msg # send message on death
42		40
		41	=head1 CURRENT STATUS
		42
		43	AnyEvent::MP - stable API, should work
		44	AnyEvent::MP::Intro - outdated
		45	AnyEvent::MP::Kernel - mostly stable
		46	AnyEvent::MP::Global - mostly stable
		47	AnyEvent::MP::Node - mostly stable, but internal anyways
		48	AnyEvent::MP::Transport - mostly stable, but internal anyways
		49
		50	stay tuned.
		51
43	=head1 DESCRIPTION	52	=head1 DESCRIPTION
44		53
45	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
46		55
47	Despite its simplicity, you can securely message other processes running	56	Despite its simplicity, you can securely message other processes running
48	on the same or other hosts.	57	on the same or other hosts, and you can supervise entities remotely.
49		58
50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	59	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
51	manual page.	60	manual page and the examples under F<eg/>.
52		61
53	At the moment, this module family is severly broken and underdocumented,	62	At the moment, this module family is a bit underdocumented.
54	so do not use. This was uploaded mainly to reserve the CPAN namespace -
55	stay tuned! The basic API should be finished, however.
56		63
57	=head1 CONCEPTS	64	=head1 CONCEPTS
58		65
59	=over 4	66	=over 4
60		67
61	=item port	68	=item port
62		69
63	A port is something you can send messages to (with the C<snd> function).	70	A port is something you can send messages to (with the C<snd> function).
64		71
65	Some ports allow you to register C<rcv> handlers that can match specific	72	Ports allow you to register C<rcv> handlers that can match all or just
66	messages. All C<rcv> handlers will receive messages they match, messages	73	some messages. Messages send to ports will not be queued, regardless of
67	will not be queued.	74	anything was listening for them or not.
68		75
69	=item port id - C<noderef#portname>	76	=item port ID - C<nodeid#portname>
70		77
71	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	78	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as
72	separator, and a port name (a printable string of unspecified format). An	79	separator, and a port name (a printable string of unspecified format).
73	exception is the the node port, whose ID is identical to its node
74	reference.
75		80
76	=item node	81	=item node
77		82
78	A node is a single process containing at least one port - the node	83	A node is a single process containing at least one port - the node port,
79	port. You can send messages to node ports to find existing ports or to	84	which enables nodes to manage each other remotely, and to create new
80	create new ports, among other things.	85	ports.
81		86
82	Nodes are either private (single-process only), slaves (connected to a	87	Nodes are either public (have one or more listening ports) or private
83	master node only) or public nodes (connectable from unrelated nodes).	88	(no listening ports). Private nodes cannot talk to other private nodes
		89	currently.
84		90
85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	91	=item node ID - C<[a-za-Z0-9_\-.:]+>
86		92
87	A node reference is a string that either simply identifies the node (for	93	A node ID is a string that uniquely identifies the node within a
88	private and slave nodes), or contains a recipe on how to reach a given	94	network. Depending on the configuration used, node IDs can look like a
89	node (for public nodes).	95	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		96	doesn't interpret node IDs in any way.
90		97
91	This recipe is simply a comma-separated list of C<address:port> pairs (for	98	=item binds - C<ip:port>
92	TCP/IP, other protocols might look different).
93		99
94	Node references come in two flavours: resolved (containing only numerical	100	Nodes can only talk to each other by creating some kind of connection to
95	addresses) or unresolved (where hostnames are used instead of addresses).	101	each other. To do this, nodes should listen on one or more local transport
		102	endpoints - binds. Currently, only standard C<ip:port> specifications can
		103	be used, which specify TCP ports to listen on.
96		104
97	Before using an unresolved node reference in a message you first have to	105	=item seeds - C<host:port>
98	resolve it.	106
		107	When a node starts, it knows nothing about the network. To teach the node
		108	about the network it first has to contact some other node within the
		109	network. This node is called a seed.
		110
		111	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		112	are expected to be long-running, and at least one of those should always
		113	be available. When nodes run out of connections (e.g. due to a network
		114	error), they try to re-establish connections to some seednodes again to
		115	join the network.
		116
		117	Apart from being sued for seeding, seednodes are not special in any way -
		118	every public node can be a seednode.
99		119
100	=back	120	=back
101		121
102	=head1 VARIABLES/FUNCTIONS	122	=head1 VARIABLES/FUNCTIONS
103		123
…		…
105		125
106	=cut	126	=cut
107		127
108	package AnyEvent::MP;	128	package AnyEvent::MP;
109		129
110	use AnyEvent::MP::Base;	130	use AnyEvent::MP::Kernel;
111		131
112	use common::sense;	132	use common::sense;
113		133
114	use Carp ();	134	use Carp ();
115		135
116	use AE ();	136	use AE ();
117		137
118	use base "Exporter";	138	use base "Exporter";
119		139
120	our $VERSION = '0.1';	140	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		141
121	our @EXPORT = qw(	142	our @EXPORT = qw(
122	NODE $NODE *SELF node_of _any_	143	NODE $NODE *SELF node_of after
123	resolve_node initialise_node	144	initialise_node
124	snd rcv mon kil reg psub spawn	145	snd rcv mon mon_guard kil reg psub spawn
125	port	146	port
126	);	147	);
127		148
128	our $SELF;	149	our $SELF;
129		150
…		…
133	kil $SELF, die => $msg;	154	kil $SELF, die => $msg;
134	}	155	}
135		156
136	=item $thisnode = NODE / $NODE	157	=item $thisnode = NODE / $NODE
137		158
138	The C<NODE> function returns, and the C<$NODE> variable contains	159	The C<NODE> function returns, and the C<$NODE> variable contains, the node
139	the noderef of the local node. The value is initialised by a call	160	ID of the node running in the current process. This value is initialised by
140	to C<become_public> or C<become_slave>, after which all local port	161	a call to C<initialise_node>.
141	identifiers become invalid.
142		162
143	=item $noderef = node_of $port	163	=item $nodeid = node_of $port
144		164
145	Extracts and returns the noderef from a portid or a noderef.	165	Extracts and returns the node ID from a port ID or a node ID.
146		166
147	=item initialise_node $noderef, $seednode, $seednode...	167	=item initialise_node $profile_name
148		168
149	=item initialise_node "slave/", $master, $master...
150
151	Before a node can talk to other nodes on the network it has to initialise	169	Before a node can talk to other nodes on the network (i.e. enter
152	itself - the minimum a node needs to know is it's own name, and optionally	170	"distributed mode") it has to initialise itself - the minimum a node needs
153	it should know the noderefs of some other nodes in the network.	171	to know is its own name, and optionally it should know the addresses of
		172	some other nodes in the network to discover other nodes.
154		173
155	This function initialises a node - it must be called exactly once (or	174	This function initialises a node - it must be called exactly once (or
156	never) before calling other AnyEvent::MP functions.	175	never) before calling other AnyEvent::MP functions.
157		176
158	All arguments are noderefs, which can be either resolved or unresolved.	177	The first argument is a profile name. If it is C<undef> or missing, then
		178	the current nodename will be used instead (i.e. F<uname -n>).
159		179
160	There are two types of networked nodes, public nodes and slave nodes:	180	The function then looks up the profile in the aemp configuration (see the
		181	L<aemp> commandline utility).
161		182
162	=over 4	183	If the profile specifies a node ID, then this will become the node ID of
		184	this process. If not, then the profile name will be used as node ID. The
		185	special node ID of C<anon/> will be replaced by a random node ID.
163		186
164	=item public nodes	187	The next step is to look up the binds in the profile, followed by binding
		188	aemp protocol listeners on all binds specified (it is possible and valid
		189	to have no binds, meaning that the node cannot be contacted form the
		190	outside. This means the node cannot talk to other nodes that also have no
		191	binds, but it can still talk to all "normal" nodes).
165		192
166	For public nodes, C<$noderef> must either be a (possibly unresolved)	193	If the profile does not specify a binds list, then the node ID will be
167	noderef, in which case it will be resolved, or C<undef> (or missing), in	194	treated as if it were of the form C<host:port>, which will be resolved and
168	which case the noderef will be guessed.	195	used as binds list.
169		196
170	Afterwards, the node will bind itself on all endpoints and try to connect	197	Lastly, the seeds list from the profile is passed to the
171	to all additional C<$seednodes> that are specified. Seednodes are optional	198	L<AnyEvent::MP::Global> module, which will then use it to keep
172	and can be used to quickly bootstrap the node into an existing network.	199	connectivity with at least on of those seed nodes at any point in time.
173		200
174	=item slave nodes	201	Example: become a distributed node listening on the guessed noderef, or
175		202	the one specified via C<aemp> for the current node. This should be the
176	When the C<$noderef> is the special string C<slave/>, then the node will	203	most common form of invocation for "daemon"-type nodes.
177	become a slave node. Slave nodes cannot be contacted from outside and will
178	route most of their traffic to the master node that they attach to.
179
180	At least one additional noderef is required: The node will try to connect
181	to all of them and will become a slave attached to the first node it can
182	successfully connect to.
183
184	=back
185
186	This function will block until all nodes have been resolved and, for slave
187	nodes, until it has successfully established a connection to a master
188	server.
189
190	Example: become a public node listening on the default node.
191		204
192	initialise_node;	205	initialise_node;
193		206
194	Example: become a public node, and try to contact some well-known master	207	Example: become an anonymous node. This form is often used for commandline
195	servers to become part of the network.	208	clients.
196		209
197	initialise_node undef, "master1", "master2";
198
199	Example: become a public node listening on port C<4041>.
200
201	initialise_node 4041;	210	initialise_node "anon/";
202		211
203	Example: become a public node, only visible on localhost port 4044.	212	Example: become a distributed node. If there is no profile of the given
		213	name, or no binds list was specified, resolve C<localhost:4044> and bind
		214	on the resulting addresses.
204		215
205	initialise_node "locahost:4044";	216	initialise_node "localhost:4044";
206
207	Example: become a slave node to any of the specified master servers.
208
209	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
210
211	=item $cv = resolve_node $noderef
212
213	Takes an unresolved node reference that may contain hostnames and
214	abbreviated IDs, resolves all of them and returns a resolved node
215	reference.
216
217	In addition to C<address:port> pairs allowed in resolved noderefs, the
218	following forms are supported:
219
220	=over 4
221
222	=item the empty string
223
224	An empty-string component gets resolved as if the default port (4040) was
225	specified.
226
227	=item naked port numbers (e.g. C<1234>)
228
229	These are resolved by prepending the local nodename and a colon, to be
230	further resolved.
231
232	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
233
234	These are resolved by using AnyEvent::DNS to resolve them, optionally
235	looking up SRV records for the C<aemp=4040> port, if no port was
236	specified.
237
238	=back
239		217
240	=item $SELF	218	=item $SELF
241		219
242	Contains the current port id while executing C<rcv> callbacks or C<psub>	220	Contains the current port id while executing C<rcv> callbacks or C<psub>
243	blocks.	221	blocks.
244		222
245	=item SELF, %SELF, @SELF...	223	=item *SELF, SELF, %SELF, @SELF...
246		224
247	Due to some quirks in how perl exports variables, it is impossible to	225	Due to some quirks in how perl exports variables, it is impossible to
248	just export C<$SELF>, all the symbols called C<SELF> are exported by this	226	just export C<$SELF>, all the symbols named C<SELF> are exported by this
249	module, but only C<$SELF> is currently used.	227	module, but only C<$SELF> is currently used.
250		228
251	=item snd $port, type => @data	229	=item snd $port, type => @data
252		230
253	=item snd $port, @msg	231	=item snd $port, @msg
254		232
255	Send the given message to the given port ID, which can identify either	233	Send the given message to the given port, which can identify either a
256	a local or a remote port, and can be either a string or soemthignt hat	234	local or a remote port, and must be a port ID.
257	stringifies a sa port ID (such as a port object :).
258		235
259	While the message can be about anything, it is highly recommended to use a	236	While the message can be almost anything, it is highly recommended to
260	string as first element (a portid, or some word that indicates a request	237	use a string as first element (a port ID, or some word that indicates a
261	type etc.).	238	request type etc.) and to consist if only simple perl values (scalars,
		239	arrays, hashes) - if you think you need to pass an object, think again.
262		240
263	The message data effectively becomes read-only after a call to this	241	The message data logically becomes read-only after a call to this
264	function: modifying any argument is not allowed and can cause many	242	function: modifying any argument (or values referenced by them) is
265	problems.	243	forbidden, as there can be considerable time between the call to C<snd>
		244	and the time the message is actually being serialised - in fact, it might
		245	never be copied as within the same process it is simply handed to the
		246	receiving port.
266		247
267	The type of data you can transfer depends on the transport protocol: when	248	The type of data you can transfer depends on the transport protocol: when
268	JSON is used, then only strings, numbers and arrays and hashes consisting	249	JSON is used, then only strings, numbers and arrays and hashes consisting
269	of those are allowed (no objects). When Storable is used, then anything	250	of those are allowed (no objects). When Storable is used, then anything
270	that Storable can serialise and deserialise is allowed, and for the local	251	that Storable can serialise and deserialise is allowed, and for the local
271	node, anything can be passed.	252	node, anything can be passed. Best rely only on the common denominator of
		253	these.
272		254
273	=item $local_port = port	255	=item $local_port = port
274		256
275	Create a new local port object that can be used either as a pattern	257	Create a new local port object and returns its port ID. Initially it has
276	matching port ("full port") or a single-callback port ("miniport"),	258	no callbacks set and will throw an error when it receives messages.
277	depending on how C<rcv> callbacks are bound to the object.
278		259
279	=item $port = port { my @msg = @_; $finished }	260	=item $local_port = port { my @msg = @_ }
280		261
281	Creates a "miniport", that is, a very lightweight port without any pattern	262	Creates a new local port, and returns its ID. Semantically the same as
282	matching behind it, and returns its ID. Semantically the same as creating
283	a port and calling C<rcv $port, $callback> on it.	263	creating a port and calling C<rcv $port, $callback> on it.
284		264
285	The block will be called for every message received on the port. When the	265	The block will be called for every message received on the port, with the
286	callback returns a true value its job is considered "done" and the port	266	global variable C<$SELF> set to the port ID. Runtime errors will cause the
287	will be destroyed. Otherwise it will stay alive.	267	port to be C<kil>ed. The message will be passed as-is, no extra argument
		268	(i.e. no port ID) will be passed to the callback.
288		269
289	The message will be passed as-is, no extra argument (i.e. no port id) will	270	If you want to stop/destroy the port, simply C<kil> it:
290	be passed to the callback.
291		271
292	If you need the local port id in the callback, this works nicely:	272	my $port = port {
293		273	my @msg = @_;
294	my $port; $port = port {	274	...
295	snd $otherport, reply => $port;	275	kil $SELF;
296	};	276	};
297		277
298	=cut	278	=cut
299		279
300	sub rcv($@);	280	sub rcv($@);
		281
		282	sub _kilme {
		283	die "received message on port without callback";
		284	}
301		285
302	sub port(;&) {	286	sub port(;&) {
303	my $id = "$UNIQ." . $ID++;	287	my $id = "$UNIQ." . $ID++;
304	my $port = "$NODE#$id";	288	my $port = "$NODE#$id";
305		289
306	if (@_) {	290	rcv $port, shift \|\| \&_kilme;
307	rcv $port, shift;
308	} else {
309	$PORT{$id} = sub { }; # nop
310	}
311		291
312	$port	292	$port
313	}	293	}
314		294
315	=item reg $port, $name
316
317	=item reg $name
318
319	Registers the given port (or C<$SELF><<< if missing) under the name
320	C<$name>. If the name already exists it is replaced.
321
322	A port can only be registered under one well known name.
323
324	A port automatically becomes unregistered when it is killed.
325
326	=cut
327
328	sub reg(@) {
329	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
330
331	$REG{$_[0]} = $port;
332	}
333
334	=item rcv $port, $callback->(@msg)	295	=item rcv $local_port, $callback->(@msg)
335		296
336	Replaces the callback on the specified miniport (after converting it to	297	Replaces the default callback on the specified port. There is no way to
337	one if required).	298	remove the default callback: use C<sub { }> to disable it, or better
338		299	C<kil> the port when it is no longer needed.
339	=item rcv $port, tagstring => $callback->(@msg), ...
340
341	=item rcv $port, $smartmatch => $callback->(@msg), ...
342
343	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
344
345	Register callbacks to be called on matching messages on the given full
346	port (after converting it to one if required) and return the port.
347
348	The callback has to return a true value when its work is done, after
349	which is will be removed, or a false value in which case it will stay
350	registered.
351		300
352	The global C<$SELF> (exported by this module) contains C<$port> while	301	The global C<$SELF> (exported by this module) contains C<$port> while
353	executing the callback.	302	executing the callback. Runtime errors during callback execution will
		303	result in the port being C<kil>ed.
354		304
355	Runtime errors during callback execution will result in the port being	305	The default callback received all messages not matched by a more specific
356	C<kil>ed.	306	C<tag> match.
357		307
358	If the match is an array reference, then it will be matched against the	308	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
359	first elements of the message, otherwise only the first element is being
360	matched.
361		309
362	Any element in the match that is specified as C<_any_> (a function	310	Register (or replace) callbacks to be called on messages starting with the
363	exported by this module) matches any single element of the message.	311	given tag on the given port (and return the port), or unregister it (when
		312	C<$callback> is C<$undef> or missing). There can only be one callback
		313	registered for each tag.
364		314
365	While not required, it is highly recommended that the first matching	315	The original message will be passed to the callback, after the first
366	element is a string identifying the message. The one-string-only match is	316	element (the tag) has been removed. The callback will use the same
367	also the most efficient match (by far).	317	environment as the default callback (see above).
368		318
369	Example: create a port and bind receivers on it in one go.	319	Example: create a port and bind receivers on it in one go.
370		320
371	my $port = rcv port,	321	my $port = rcv port,
372	msg1 => sub { ...; 0 },	322	msg1 => sub { ... },
373	msg2 => sub { ...; 0 },	323	msg2 => sub { ... },
374	;	324	;
375		325
376	Example: create a port, bind receivers and send it in a message elsewhere	326	Example: create a port, bind receivers and send it in a message elsewhere
377	in one go:	327	in one go:
378		328
379	snd $otherport, reply =>	329	snd $otherport, reply =>
380	rcv port,	330	rcv port,
381	msg1 => sub { ...; 0 },	331	msg1 => sub { ... },
382	...	332	...
383	;	333	;
		334
		335	Example: temporarily register a rcv callback for a tag matching some port
		336	(e.g. for a rpc reply) and unregister it after a message was received.
		337
		338	rcv $port, $otherport => sub {
		339	my @reply = @_;
		340
		341	rcv $SELF, $otherport;
		342	};
384		343
385	=cut	344	=cut
386		345
387	sub rcv($@) {	346	sub rcv($@) {
388	my $port = shift;	347	my $port = shift;
389	my ($noderef, $portid) = split /#/, $port, 2;	348	my ($noderef, $portid) = split /#/, $port, 2;
390		349
391	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	350	$NODE{$noderef} == $NODE{""}
392	or Carp::croak "$port: rcv can only be called on local ports, caught";	351	or Carp::croak "$port: rcv can only be called on local ports, caught";
393		352
394	if (@_ == 1) {	353	while (@_) {
		354	if (ref $_[0]) {
		355	if (my $self = $PORT_DATA{$portid}) {
		356	"AnyEvent::MP::Port" eq ref $self
		357	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		358
		359	$self->[2] = shift;
		360	} else {
395	my $cb = shift;	361	my $cb = shift;
396	delete $PORT_DATA{$portid};
397	$PORT{$portid} = sub {	362	$PORT{$portid} = sub {
398	local $SELF = $port;	363	local $SELF = $port;
399	eval {	364	eval { &$cb }; _self_die if $@;
400	&$cb	365	};
401	and kil $port;
402	};	366	}
403	_self_die if $@;	367	} elsif (defined $_[0]) {
404	};
405	} else {
406	my $self = $PORT_DATA{$portid} \|\|= do {	368	my $self = $PORT_DATA{$portid} \|\|= do {
407	my $self = bless {	369	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
408	id => $port,
409	}, "AnyEvent::MP::Port";
410		370
411	$PORT{$portid} = sub {	371	$PORT{$portid} = sub {
412	local $SELF = $port;	372	local $SELF = $port;
413		373
414	eval {
415	for (@{ $self->{rc0}{$_[0]} }) {	374	if (my $cb = $self->[1]{$_[0]}) {
416	$_ && &{$_->[0]}	375	shift;
417	&& undef $_;	376	eval { &$cb }; _self_die if $@;
418	}	377	} else {
419
420	for (@{ $self->{rcv}{$_[0]} }) {
421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
422	&& &{$_->[0]}	378	&{ $self->[0] };
423	&& undef $_;
424	}
425
426	for (@{ $self->{any} }) {
427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
428	&& &{$_->[0]}
429	&& undef $_;
430	}	379	}
431	};	380	};
432	_self_die if $@;	381
		382	$self
433	};	383	};
434		384
435	$self
436	};
437
438	"AnyEvent::MP::Port" eq ref $self	385	"AnyEvent::MP::Port" eq ref $self
439	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	386	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
440		387
441	while (@_) {
442	my ($match, $cb) = splice @_, 0, 2;	388	my ($tag, $cb) = splice @_, 0, 2;
443		389
444	if (!ref $match) {	390	if (defined $cb) {
445	push @{ $self->{rc0}{$match} }, [$cb];	391	$self->[1]{$tag} = $cb;
446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
447	my ($type, @match) = @$match;
448	@match
449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
451	} else {	392	} else {
452	push @{ $self->{any} }, [$cb, $match];	393	delete $self->[1]{$tag};
453	}	394	}
454	}	395	}
455	}	396	}
456		397
457	$port	398	$port
…		…
493	$res	434	$res
494	}	435	}
495	}	436	}
496	}	437	}
497		438
498	=item $guard = mon $port, $cb->(@reason)	439	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
499		440
500	=item $guard = mon $port, $rcvport	441	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
501		442
502	=item $guard = mon $port	443	=item $guard = mon $port # kill $SELF when $port dies
503		444
504	=item $guard = mon $port, $rcvport, @msg	445	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
505		446
506	Monitor the given port and do something when the port is killed, and	447	Monitor the given port and do something when the port is killed or
507	optionally return a guard that can be used to stop monitoring again.	448	messages to it were lost, and optionally return a guard that can be used
		449	to stop monitoring again.
		450
		451	C<mon> effectively guarantees that, in the absence of hardware failures,
		452	after starting the monitor, either all messages sent to the port will
		453	arrive, or the monitoring action will be invoked after possible message
		454	loss has been detected. No messages will be lost "in between" (after
		455	the first lost message no further messages will be received by the
		456	port). After the monitoring action was invoked, further messages might get
		457	delivered again.
		458
		459	Note that monitoring-actions are one-shot: once messages are lost (and a
		460	monitoring alert was raised), they are removed and will not trigger again.
508		461
509	In the first form (callback), the callback is simply called with any	462	In the first form (callback), the callback is simply called with any
510	number of C<@reason> elements (no @reason means that the port was deleted	463	number of C<@reason> elements (no @reason means that the port was deleted
511	"normally"). Note also that I<< the callback B<must> never die >>, so use	464	"normally"). Note also that I<< the callback B<must> never die >>, so use
512	C<eval> if unsure.	465	C<eval> if unsure.
513		466
514	In the second form (another port given), the other port (C<$rcvport)	467	In the second form (another port given), the other port (C<$rcvport>)
515	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	468	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
516	"normal" kils nothing happens, while under all other conditions, the other	469	"normal" kils nothing happens, while under all other conditions, the other
517	port is killed with the same reason.	470	port is killed with the same reason.
518		471
519	The third form (kill self) is the same as the second form, except that	472	The third form (kill self) is the same as the second form, except that
…		…
546	sub mon {	499	sub mon {
547	my ($noderef, $port) = split /#/, shift, 2;	500	my ($noderef, $port) = split /#/, shift, 2;
548		501
549	my $node = $NODE{$noderef} \|\| add_node $noderef;	502	my $node = $NODE{$noderef} \|\| add_node $noderef;
550		503
551	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	504	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
552		505
553	unless (ref $cb) {	506	unless (ref $cb) {
554	if (@_) {	507	if (@_) {
555	# send a kill info message	508	# send a kill info message
556	my (@msg) = @_;	509	my (@msg) = ($cb, @_);
557	$cb = sub { snd @msg, @_ };	510	$cb = sub { snd @msg, @_ };
558	} else {	511	} else {
559	# simply kill other port	512	# simply kill other port
560	my $port = $cb;	513	my $port = $cb;
561	$cb = sub { kil $port, @_ if @_ };	514	$cb = sub { kil $port, @_ if @_ };
…		…
574	is killed, the references will be freed.	527	is killed, the references will be freed.
575		528
576	Optionally returns a guard that will stop the monitoring.	529	Optionally returns a guard that will stop the monitoring.
577		530
578	This function is useful when you create e.g. timers or other watchers and	531	This function is useful when you create e.g. timers or other watchers and
579	want to free them when the port gets killed:	532	want to free them when the port gets killed (note the use of C<psub>):
580		533
581	$port->rcv (start => sub {	534	$port->rcv (start => sub {
582	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	535	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
583	undef $timer if 0.9 < rand;	536	undef $timer if 0.9 < rand;
584	});	537	});
585	});	538	});
586		539
587	=cut	540	=cut
…		…
596		549
597	=item kil $port[, @reason]	550	=item kil $port[, @reason]
598		551
599	Kill the specified port with the given C<@reason>.	552	Kill the specified port with the given C<@reason>.
600		553
601	If no C<@reason> is specified, then the port is killed "normally" (linked	554	If no C<@reason> is specified, then the port is killed "normally" (ports
602	ports will not be kileld, or even notified).	555	monitoring other ports will not necessarily die because a port dies
		556	"normally").
603		557
604	Otherwise, linked ports get killed with the same reason (second form of	558	Otherwise, linked ports get killed with the same reason (second form of
605	C<mon>, see below).	559	C<mon>, see above).
606		560
607	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	561	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
608	will be reported as reason C<< die => $@ >>.	562	will be reported as reason C<< die => $@ >>.
609		563
610	Transport/communication errors are reported as C<< transport_error =>	564	Transport/communication errors are reported as C<< transport_error =>
…		…
615	=item $port = spawn $node, $initfunc[, @initdata]	569	=item $port = spawn $node, $initfunc[, @initdata]
616		570
617	Creates a port on the node C<$node> (which can also be a port ID, in which	571	Creates a port on the node C<$node> (which can also be a port ID, in which
618	case it's the node where that port resides).	572	case it's the node where that port resides).
619		573
620	The port ID of the newly created port is return immediately, and it is	574	The port ID of the newly created port is returned immediately, and it is
621	permissible to immediately start sending messages or monitor the port.	575	possible to immediately start sending messages or to monitor the port.
622		576
623	After the port has been created, the init function is	577	After the port has been created, the init function is called on the remote
624	called. This function must be a fully-qualified function name	578	node, in the same context as a C<rcv> callback. This function must be a
625	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	579	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
626	program, use C<::name>.	580	specify a function in the main program, use C<::name>.
627		581
628	If the function doesn't exist, then the node tries to C<require>	582	If the function doesn't exist, then the node tries to C<require>
629	the package, then the package above the package and so on (e.g.	583	the package, then the package above the package and so on (e.g.
630	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	584	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
631	exists or it runs out of package names.	585	exists or it runs out of package names.
632		586
633	The init function is then called with the newly-created port as context	587	The init function is then called with the newly-created port as context
634	object (C<$SELF>) and the C<@initdata> values as arguments.	588	object (C<$SELF>) and the C<@initdata> values as arguments.
635		589
636	A common idiom is to pass your own port, monitor the spawned port, and	590	A common idiom is to pass a local port, immediately monitor the spawned
637	in the init function, monitor the original port. This two-way monitoring	591	port, and in the remote init function, immediately monitor the passed
638	ensures that both ports get cleaned up when there is a problem.	592	local port. This two-way monitoring ensures that both ports get cleaned up
		593	when there is a problem.
639		594
640	Example: spawn a chat server port on C<$othernode>.	595	Example: spawn a chat server port on C<$othernode>.
641		596
642	# this node, executed from within a port context:	597	# this node, executed from within a port context:
643	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	598	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
673	my $id = "$RUNIQ." . $ID++;	628	my $id = "$RUNIQ." . $ID++;
674		629
675	$_[0] =~ /::/	630	$_[0] =~ /::/
676	or Carp::croak "spawn init function must be a fully-qualified name, caught";	631	or Carp::croak "spawn init function must be a fully-qualified name, caught";
677		632
678	($NODE{$noderef} \|\| add_node $noderef)	633	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;
679	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
680		634
681	"$noderef#$id"	635	"$noderef#$id"
682	}	636	}
683		637
684	=back	638	=item after $timeout, @msg
685		639
686	=head1 NODE MESSAGES	640	=item after $timeout, $callback
687		641
688	Nodes understand the following messages sent to them. Many of them take	642	Either sends the given message, or call the given callback, after the
689	arguments called C<@reply>, which will simply be used to compose a reply	643	specified number of seconds.
690	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
691	the remaining arguments are simply the message data.
692		644
693	While other messages exist, they are not public and subject to change.	645	This is simply a utility function that comes in handy at times - the
		646	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		647	so it may go away in the future.
694		648
695	=over 4
696
697	=cut	649	=cut
698		650
699	=item lookup => $name, @reply	651	sub after($@) {
		652	my ($timeout, @action) = @_;
700		653
701	Replies with the port ID of the specified well-known port, or C<undef>.	654	my $t; $t = AE::timer $timeout, 0, sub {
702		655	undef $t;
703	=item devnull => ...	656	ref $action[0]
704		657	? $action[0]()
705	Generic data sink/CPU heat conversion.	658	: snd @action;
706		659	};
707	=item relay => $port, @msg	660	}
708
709	Simply forwards the message to the given port.
710
711	=item eval => $string[ @reply]
712
713	Evaluates the given string. If C<@reply> is given, then a message of the
714	form C<@reply, $@, @evalres> is sent.
715
716	Example: crash another node.
717
718	snd $othernode, eval => "exit";
719
720	=item time => @reply
721
722	Replies the the current node time to C<@reply>.
723
724	Example: tell the current node to send the current time to C<$myport> in a
725	C<timereply> message.
726
727	snd $NODE, time => $myport, timereply => 1, 2;
728	# => snd $myport, timereply => 1, 2, <time>
729		661
730	=back	662	=back
731		663
732	=head1 AnyEvent::MP vs. Distributed Erlang	664	=head1 AnyEvent::MP vs. Distributed Erlang
733		665
…		…
743		675
744	Despite the similarities, there are also some important differences:	676	Despite the similarities, there are also some important differences:
745		677
746	=over 4	678	=over 4
747		679
748	=item * Node references contain the recipe on how to contact them.	680	=item * Node IDs are arbitrary strings in AEMP.
749		681
750	Erlang relies on special naming and DNS to work everywhere in the	682	Erlang relies on special naming and DNS to work everywhere in the same
751	same way. AEMP relies on each node knowing it's own address(es), with	683	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
752	convenience functionality.	684	configuraiton or DNS), but will otherwise discover other odes itself.
753		685
754	This means that AEMP requires a less tightly controlled environment at the	686	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
755	cost of longer node references and a slightly higher management overhead.	687	uses "local ports are like remote ports".
		688
		689	The failure modes for local ports are quite different (runtime errors
		690	only) then for remote ports - when a local port dies, you I<know> it dies,
		691	when a connection to another node dies, you know nothing about the other
		692	port.
		693
		694	Erlang pretends remote ports are as reliable as local ports, even when
		695	they are not.
		696
		697	AEMP encourages a "treat remote ports differently" philosophy, with local
		698	ports being the special case/exception, where transport errors cannot
		699	occur.
756		700
757	=item * Erlang uses processes and a mailbox, AEMP does not queue.	701	=item * Erlang uses processes and a mailbox, AEMP does not queue.
758		702
759	Erlang uses processes that selctively receive messages, and therefore	703	Erlang uses processes that selectively receive messages, and therefore
760	needs a queue. AEMP is event based, queuing messages would serve no useful	704	needs a queue. AEMP is event based, queuing messages would serve no
761	purpose.	705	useful purpose. For the same reason the pattern-matching abilities of
		706	AnyEvent::MP are more limited, as there is little need to be able to
		707	filter messages without dequeing them.
762		708
763	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	709	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
764		710
765	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	711	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
766		712
767	Sending messages in Erlang is synchronous and blocks the process. AEMP	713	Sending messages in Erlang is synchronous and blocks the process (and
768	sends are immediate, connection establishment is handled in the	714	so does not need a queue that can overflow). AEMP sends are immediate,
769	background.	715	connection establishment is handled in the background.
770		716
771	=item * Erlang can silently lose messages, AEMP cannot.	717	=item * Erlang suffers from silent message loss, AEMP does not.
772		718
773	Erlang makes few guarantees on messages delivery - messages can get lost	719	Erlang makes few guarantees on messages delivery - messages can get lost
774	without any of the processes realising it (i.e. you send messages a, b,	720	without any of the processes realising it (i.e. you send messages a, b,
775	and c, and the other side only receives messages a and c).	721	and c, and the other side only receives messages a and c).
776		722
777	AEMP guarantees correct ordering, and the guarantee that there are no	723	AEMP guarantees correct ordering, and the guarantee that after one message
778	holes in the message sequence.	724	is lost, all following ones sent to the same port are lost as well, until
779		725	monitoring raises an error, so there are no silent "holes" in the message
780	=item * In Erlang, processes can be declared dead and later be found to be	726	sequence.
781	alive.
782
783	In Erlang it can happen that a monitored process is declared dead and
784	linked processes get killed, but later it turns out that the process is
785	still alive - and can receive messages.
786
787	In AEMP, when port monitoring detects a port as dead, then that port will
788	eventually be killed - it cannot happen that a node detects a port as dead
789	and then later sends messages to it, finding it is still alive.
790		727
791	=item * Erlang can send messages to the wrong port, AEMP does not.	728	=item * Erlang can send messages to the wrong port, AEMP does not.
792		729
793	In Erlang it is quite possible that a node that restarts reuses a process	730	In Erlang it is quite likely that a node that restarts reuses a process ID
794	ID known to other nodes for a completely different process, causing	731	known to other nodes for a completely different process, causing messages
795	messages destined for that process to end up in an unrelated process.	732	destined for that process to end up in an unrelated process.
796		733
797	AEMP never reuses port IDs, so old messages or old port IDs floating	734	AEMP never reuses port IDs, so old messages or old port IDs floating
798	around in the network will not be sent to an unrelated port.	735	around in the network will not be sent to an unrelated port.
799		736
800	=item * Erlang uses unprotected connections, AEMP uses secure	737	=item * Erlang uses unprotected connections, AEMP uses secure
801	authentication and can use TLS.	738	authentication and can use TLS.
802		739
803	AEMP can use a proven protocol - SSL/TLS - to protect connections and	740	AEMP can use a proven protocol - TLS - to protect connections and
804	securely authenticate nodes.	741	securely authenticate nodes.
805		742
806	=item * The AEMP protocol is optimised for both text-based and binary	743	=item * The AEMP protocol is optimised for both text-based and binary
807	communications.	744	communications.
808		745
809	The AEMP protocol, unlike the Erlang protocol, supports both	746	The AEMP protocol, unlike the Erlang protocol, supports both programming
810	language-independent text-only protocols (good for debugging) and binary,	747	language independent text-only protocols (good for debugging) and binary,
811	language-specific serialisers (e.g. Storable).	748	language-specific serialisers (e.g. Storable). By default, unless TLS is
		749	used, the protocol is actually completely text-based.
812		750
813	It has also been carefully designed to be implementable in other languages	751	It has also been carefully designed to be implementable in other languages
814	with a minimum of work while gracefully degrading fucntionality to make the	752	with a minimum of work while gracefully degrading functionality to make the
815	protocol simple.	753	protocol simple.
816		754
817	=item * AEMP has more flexible monitoring options than Erlang.	755	=item * AEMP has more flexible monitoring options than Erlang.
818		756
819	In Erlang, you can chose to receive I<all> exit signals as messages	757	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
822	Erlang, as one can choose between automatic kill, exit message or callback	760	Erlang, as one can choose between automatic kill, exit message or callback
823	on a per-process basis.	761	on a per-process basis.
824		762
825	=item * Erlang tries to hide remote/local connections, AEMP does not.	763	=item * Erlang tries to hide remote/local connections, AEMP does not.
826		764
827	Monitoring in Erlang is not an indicator of process death/crashes,	765	Monitoring in Erlang is not an indicator of process death/crashes, in the
828	as linking is (except linking is unreliable in Erlang).	766	same way as linking is (except linking is unreliable in Erlang).
829		767
830	In AEMP, you don't "look up" registered port names or send to named ports	768	In AEMP, you don't "look up" registered port names or send to named ports
831	that might or might not be persistent. Instead, you normally spawn a port	769	that might or might not be persistent. Instead, you normally spawn a port
832	on the remote node. The init function monitors the you, and you monitor	770	on the remote node. The init function monitors you, and you monitor the
833	the remote port. Since both monitors are local to the node, they are much	771	remote port. Since both monitors are local to the node, they are much more
834	more reliable.	772	reliable (no need for C<spawn_link>).
835		773
836	This also saves round-trips and avoids sending messages to the wrong port	774	This also saves round-trips and avoids sending messages to the wrong port
837	(hard to do in Erlang).	775	(hard to do in Erlang).
838		776
839	=back	777	=back
840		778
		779	=head1 RATIONALE
		780
		781	=over 4
		782
		783	=item Why strings for port and node IDs, why not objects?
		784
		785	We considered "objects", but found that the actual number of methods
		786	that can be called are quite low. Since port and node IDs travel over
		787	the network frequently, the serialising/deserialising would add lots of
		788	overhead, as well as having to keep a proxy object everywhere.
		789
		790	Strings can easily be printed, easily serialised etc. and need no special
		791	procedures to be "valid".
		792
		793	And as a result, a miniport consists of a single closure stored in a
		794	global hash - it can't become much cheaper.
		795
		796	=item Why favour JSON, why not a real serialising format such as Storable?
		797
		798	In fact, any AnyEvent::MP node will happily accept Storable as framing
		799	format, but currently there is no way to make a node use Storable by
		800	default (although all nodes will accept it).
		801
		802	The default framing protocol is JSON because a) JSON::XS is many times
		803	faster for small messages and b) most importantly, after years of
		804	experience we found that object serialisation is causing more problems
		805	than it solves: Just like function calls, objects simply do not travel
		806	easily over the network, mostly because they will always be a copy, so you
		807	always have to re-think your design.
		808
		809	Keeping your messages simple, concentrating on data structures rather than
		810	objects, will keep your messages clean, tidy and efficient.
		811
		812	=back
		813
841	=head1 SEE ALSO	814	=head1 SEE ALSO
842		815
843	L<AnyEvent>.	816	L<AnyEvent>.
844		817
845	=head1 AUTHOR	818	=head1 AUTHOR

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.40 by root, Sat Aug 8 00:22:16 2009 UTC vs.
Revision 1.67 by root, Fri Aug 28 22:21:53 2009 UTC