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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC vs.
Revision 1.77 by elmex, Thu Sep 3 07:57:30 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
		12	$SELF # receiving/own port id in rcv callbacks
		13
		14	# initialise the node so it can send/receive messages
		15	configure;
		16
		17	# ports are message destinations
		18
		19	# sending messages
13	snd $port, type => data...;	20	snd $port, type => data...;
		21	snd $port, @msg;
		22	snd @msg_with_first_element_being_a_port;
14		23
15	$SELF # receiving/own port id in rcv callbacks	24	# creating/using ports, the simple way
		25	my $simple_port = port { my @msg = @_ };
16		26
17	rcv $port, smartmatch => $cb->($port, @msg);	27	# creating/using ports, tagged message matching
18		28	my $port = port;
19	# examples:
20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
21	rcv $port1, pong => sub { warn "pong received\n" };	30	rcv $port, pong => sub { warn "pong received\n" };
22	snd $port2, ping => $port1;
23		31
24	# more, smarter, matches (_any_ is exported by this module)	32	# create a port on another node
25	rcv $port, [child_died => $pid] => sub { ...	33	my $port = spawn $node, $initfunc, @initdata;
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
27		34
28	# monitoring	35	# monitoring
29	mon $port, $cb->(@msg) # callback is invoked on death	36	mon $port, $cb->(@msg) # callback is invoked on death
30	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
31	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
32		39
		40	=head1 CURRENT STATUS
		41
		42	bin/aemp - stable.
		43	AnyEvent::MP - stable API, should work.
		44	AnyEvent::MP::Intro - explains most concepts.
		45	AnyEvent::MP::Kernel - mostly stable.
		46	AnyEvent::MP::Global - stable API, protocol not yet final.
		47
		48	stay tuned.
		49
33	=head1 DESCRIPTION	50	=head1 DESCRIPTION
34		51
35	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
36		53
37	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
38	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
39		56
40	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	57	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
41	manual page.	58	manual page and the examples under F<eg/>.
42
43	At the moment, this module family is severly broken and underdocumented,
44	so do not use. This was uploaded mainly to reserve the CPAN namespace -
45	stay tuned! The basic API should be finished, however.
46		59
47	=head1 CONCEPTS	60	=head1 CONCEPTS
48		61
49	=over 4	62	=over 4
50		63
51	=item port	64	=item port
52		65
53	A port is something you can send messages to (with the C<snd> function).	66	A port is something you can send messages to (with the C<snd> function).
54		67
55	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
56	messages. All C<rcv> handlers will receive messages they match, messages	69	some messages. Messages send to ports will not be queued, regardless of
57	will not be queued.	70	anything was listening for them or not.
58		71
59	=item port id - C<noderef#portname>	72	=item port ID - C<nodeid#portname>
60		73
61	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
62	separator, and a port name (a printable string of unspecified format). An	75	separator, and a port name (a printable string of unspecified format).
63	exception is the the node port, whose ID is identical to its node
64	reference.
65		76
66	=item node	77	=item node
67		78
68	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,
69	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
70	create new ports, among other things.	81	ports.
71		82
72	Nodes are either private (single-process only), slaves (connected to a	83	Nodes are either public (have one or more listening ports) or private
73	master node only) or public nodes (connectable from unrelated nodes).	84	(no listening ports). Private nodes cannot talk to other private nodes
		85	currently.
74		86
75	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	87	=item node ID - C<[a-za-Z0-9_\-.:]+>
76		88
77	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
78	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
79	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.
80		93
81	This recipe is simply a comma-separated list of C<address:port> pairs (for	94	=item binds - C<ip:port>
82	TCP/IP, other protocols might look different).
83		95
84	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
85	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.
86		100
87	Before using an unresolved node reference in a message you first have to	101	=item seeds - C<host:port>
88	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.
89		115
90	=back	116	=back
91		117
92	=head1 VARIABLES/FUNCTIONS	118	=head1 VARIABLES/FUNCTIONS
93		119
…		…
95		121
96	=cut	122	=cut
97		123
98	package AnyEvent::MP;	124	package AnyEvent::MP;
99		125
100	use AnyEvent::MP::Base;	126	use AnyEvent::MP::Kernel;
101		127
102	use common::sense;	128	use common::sense;
103		129
104	use Carp ();	130	use Carp ();
105		131
106	use AE ();	132	use AE ();
107		133
108	use base "Exporter";	134	use base "Exporter";
109		135
110	our $VERSION = '0.1';	136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		137
111	our @EXPORT = qw(	138	our @EXPORT = qw(
112	NODE $NODE *SELF node_of _any_	139	NODE $NODE *SELF node_of after
113	resolve_node initialise_node	140	configure
114	snd rcv mon kil reg psub	141	snd rcv mon mon_guard kil reg psub spawn
115	port	142	port
116	);	143	);
117		144
118	our $SELF;	145	our $SELF;
119		146
…		…
123	kil $SELF, die => $msg;	150	kil $SELF, die => $msg;
124	}	151	}
125		152
126	=item $thisnode = NODE / $NODE	153	=item $thisnode = NODE / $NODE
127		154
128	The C<NODE> function returns, and the C<$NODE> variable contains	155	The C<NODE> function returns, and the C<$NODE> variable contains, the node
129	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
130	to C<become_public> or C<become_slave>, after which all local port	157	a call to C<configure>.
131	identifiers become invalid.
132		158
133	=item $noderef = node_of $port	159	=item $nodeid = node_of $port
134		160
135	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.
136		162
137	=item initialise_node $noderef, $seednode, $seednode...	163	=item configure key => value...
138		164
139	=item initialise_node "slave/", $master, $master...
140
141	Before a node can talk to other nodes on the network it has to initialise	165	Before a node can talk to other nodes on the network (i.e. enter
142	itself - the minimum a node needs to know is it's own name, and optionally	166	"distributed mode") it has to configure itself - the minimum a node needs
143	it should know the noderefs of some other nodes in the network.	167	to know is its own name, and optionally it should know the addresses of
		168	some other nodes in the network to discover other nodes.
144		169
145	This function initialises a node - it must be called exactly once (or	170	This function configures a node - it must be called exactly once (or
146	never) before calling other AnyEvent::MP functions.	171	never) before calling other AnyEvent::MP functions.
147		172
148	All arguments are noderefs, which can be either resolved or unresolved.
149
150	There are two types of networked nodes, public nodes and slave nodes:
151
152	=over 4	173	=over 4
153		174
154	=item public nodes	175	=item step 1, gathering configuration from profiles
155		176
156	For public nodes, C<$noderef> must either be a (possibly unresolved)	177	The function first looks up a profile in the aemp configuration (see the
157	noderef, in which case it will be resolved, or C<undef> (or missing), in	178	L<aemp> commandline utility). The profile name can be specified via the
158	which case the noderef will be guessed.	179	named C<profile> parameter. If it is missing, then the nodename (F<uname
		180	-n>) will be used as profile name.
159		181
160	Afterwards, the node will bind itself on all endpoints and try to connect	182	The profile data is then gathered as follows:
161	to all additional C<$seednodes> that are specified. Seednodes are optional
162	and can be used to quickly bootstrap the node into an existing network.
163		183
164	=item slave nodes	184	First, all remaining key => value pairs (all of which are conveniently
		185	undocumented at the moment) will be interpreted as configuration
		186	data. Then they will be overwritten by any values specified in the global
		187	default configuration (see the F<aemp> utility), then the chain of
		188	profiles chosen by the profile name (and any C<parent> attributes).
165		189
166	When the C<$noderef> is the special string C<slave/>, then the node will	190	That means that the values specified in the profile have highest priority
167	become a slave node. Slave nodes cannot be contacted from outside and will	191	and the values specified directly via C<configure> have lowest priority,
168	route most of their traffic to the master node that they attach to.	192	and can only be used to specify defaults.
169		193
170	At least one additional noderef is required: The node will try to connect	194	If the profile specifies a node ID, then this will become the node ID of
171	to all of them and will become a slave attached to the first node it can	195	this process. If not, then the profile name will be used as node ID. The
172	successfully connect to.	196	special node ID of C<anon/> will be replaced by a random node ID.
		197
		198	=item step 2, bind listener sockets
		199
		200	The next step is to look up the binds in the profile, followed by binding
		201	aemp protocol listeners on all binds specified (it is possible and valid
		202	to have no binds, meaning that the node cannot be contacted form the
		203	outside. This means the node cannot talk to other nodes that also have no
		204	binds, but it can still talk to all "normal" nodes).
		205
		206	If the profile does not specify a binds list, then a default of C<*> is
		207	used, meaning the node will bind on a dynamically-assigned port on every
		208	local IP address it finds.
		209
		210	=item step 3, connect to seed nodes
		211
		212	As the last step, the seeds list from the profile is passed to the
		213	L<AnyEvent::MP::Global> module, which will then use it to keep
		214	connectivity with at least one node at any point in time.
173		215
174	=back	216	=back
175		217
176	This function will block until all nodes have been resolved and, for slave	218	Example: become a distributed node using the locla node name as profile.
177	nodes, until it has successfully established a connection to a master	219	This should be the most common form of invocation for "daemon"-type nodes.
178	server.
179		220
180	Example: become a public node listening on the default node.	221	configure
181		222
182	initialise_node;	223	Example: become an anonymous node. This form is often used for commandline
		224	clients.
183		225
184	Example: become a public node, and try to contact some well-known master	226	configure nodeid => "anon/";
185	servers to become part of the network.
186		227
187	initialise_node undef, "master1", "master2";	228	Example: configure a node using a profile called seed, which si suitable
		229	for a seed node as it binds on all local addresses on a fixed port (4040,
		230	customary for aemp).
188		231
189	Example: become a public node listening on port C<4041>.	232	# use the aemp commandline utility
		233	# aemp profile seed nodeid anon/ binds '*:4040'
190		234
191	initialise_node 4041;	235	# then use it
		236	configure profile => "seed";
192		237
193	Example: become a public node, only visible on localhost port 4044.	238	# or simply use aemp from the shell again:
		239	# aemp run profile seed
194		240
195	initialise_node "locahost:4044";	241	# or provide a nicer-to-remember nodeid
196		242	# aemp run profile seed nodeid "$(hostname)"
197	Example: become a slave node to any of the specified master servers.
198
199	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
200
201	=item $cv = resolve_node $noderef
202
203	Takes an unresolved node reference that may contain hostnames and
204	abbreviated IDs, resolves all of them and returns a resolved node
205	reference.
206
207	In addition to C<address:port> pairs allowed in resolved noderefs, the
208	following forms are supported:
209
210	=over 4
211
212	=item the empty string
213
214	An empty-string component gets resolved as if the default port (4040) was
215	specified.
216
217	=item naked port numbers (e.g. C<1234>)
218
219	These are resolved by prepending the local nodename and a colon, to be
220	further resolved.
221
222	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
223
224	These are resolved by using AnyEvent::DNS to resolve them, optionally
225	looking up SRV records for the C<aemp=4040> port, if no port was
226	specified.
227
228	=back
229		243
230	=item $SELF	244	=item $SELF
231		245
232	Contains the current port id while executing C<rcv> callbacks or C<psub>	246	Contains the current port id while executing C<rcv> callbacks or C<psub>
233	blocks.	247	blocks.
234		248
235	=item SELF, %SELF, @SELF...	249	=item *SELF, SELF, %SELF, @SELF...
236		250
237	Due to some quirks in how perl exports variables, it is impossible to	251	Due to some quirks in how perl exports variables, it is impossible to
238	just export C<$SELF>, all the symbols called C<SELF> are exported by this	252	just export C<$SELF>, all the symbols named C<SELF> are exported by this
239	module, but only C<$SELF> is currently used.	253	module, but only C<$SELF> is currently used.
240		254
241	=item snd $port, type => @data	255	=item snd $port, type => @data
242		256
243	=item snd $port, @msg	257	=item snd $port, @msg
244		258
245	Send the given message to the given port ID, which can identify either	259	Send the given message to the given port, which can identify either a
246	a local or a remote port, and can be either a string or soemthignt hat	260	local or a remote port, and must be a port ID.
247	stringifies a sa port ID (such as a port object :).
248		261
249	While the message can be about anything, it is highly recommended to use a	262	While the message can be almost anything, it is highly recommended to
250	string as first element (a portid, or some word that indicates a request	263	use a string as first element (a port ID, or some word that indicates a
251	type etc.).	264	request type etc.) and to consist if only simple perl values (scalars,
		265	arrays, hashes) - if you think you need to pass an object, think again.
252		266
253	The message data effectively becomes read-only after a call to this	267	The message data logically becomes read-only after a call to this
254	function: modifying any argument is not allowed and can cause many	268	function: modifying any argument (or values referenced by them) is
255	problems.	269	forbidden, as there can be considerable time between the call to C<snd>
		270	and the time the message is actually being serialised - in fact, it might
		271	never be copied as within the same process it is simply handed to the
		272	receiving port.
256		273
257	The type of data you can transfer depends on the transport protocol: when	274	The type of data you can transfer depends on the transport protocol: when
258	JSON is used, then only strings, numbers and arrays and hashes consisting	275	JSON is used, then only strings, numbers and arrays and hashes consisting
259	of those are allowed (no objects). When Storable is used, then anything	276	of those are allowed (no objects). When Storable is used, then anything
260	that Storable can serialise and deserialise is allowed, and for the local	277	that Storable can serialise and deserialise is allowed, and for the local
261	node, anything can be passed.	278	node, anything can be passed. Best rely only on the common denominator of
		279	these.
262		280
263	=item $local_port = port	281	=item $local_port = port
264		282
265	Create a new local port object that can be used either as a pattern	283	Create a new local port object and returns its port ID. Initially it has
266	matching port ("full port") or a single-callback port ("miniport"),	284	no callbacks set and will throw an error when it receives messages.
267	depending on how C<rcv> callbacks are bound to the object.
268		285
269	=item $port = port { my @msg = @_; $finished }	286	=item $local_port = port { my @msg = @_ }
270		287
271	Creates a "miniport", that is, a very lightweight port without any pattern	288	Creates a new local port, and returns its ID. Semantically the same as
272	matching behind it, and returns its ID. Semantically the same as creating
273	a port and calling C<rcv $port, $callback> on it.	289	creating a port and calling C<rcv $port, $callback> on it.
274		290
275	The block will be called for every message received on the port. When the	291	The block will be called for every message received on the port, with the
276	callback returns a true value its job is considered "done" and the port	292	global variable C<$SELF> set to the port ID. Runtime errors will cause the
277	will be destroyed. Otherwise it will stay alive.	293	port to be C<kil>ed. The message will be passed as-is, no extra argument
		294	(i.e. no port ID) will be passed to the callback.
278		295
279	The message will be passed as-is, no extra argument (i.e. no port id) will	296	If you want to stop/destroy the port, simply C<kil> it:
280	be passed to the callback.
281		297
282	If you need the local port id in the callback, this works nicely:	298	my $port = port {
283		299	my @msg = @_;
284	my $port; $port = port {	300	...
285	snd $otherport, reply => $port;	301	kil $SELF;
286	};	302	};
287		303
288	=cut	304	=cut
289		305
290	sub rcv($@);	306	sub rcv($@);
		307
		308	sub _kilme {
		309	die "received message on port without callback";
		310	}
291		311
292	sub port(;&) {	312	sub port(;&) {
293	my $id = "$UNIQ." . $ID++;	313	my $id = "$UNIQ." . $ID++;
294	my $port = "$NODE#$id";	314	my $port = "$NODE#$id";
295		315
296	if (@_) {	316	rcv $port, shift \|\| \&_kilme;
297	rcv $port, shift;
298	} else {
299	$PORT{$id} = sub { }; # nop
300	}
301		317
302	$port	318	$port
303	}	319	}
304		320
305	=item reg $port, $name
306
307	=item reg $name
308
309	Registers the given port (or C<$SELF><<< if missing) under the name
310	C<$name>. If the name already exists it is replaced.
311
312	A port can only be registered under one well known name.
313
314	A port automatically becomes unregistered when it is killed.
315
316	=cut
317
318	sub reg(@) {
319	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
320
321	$REG{$_[0]} = $port;
322	}
323
324	=item rcv $port, $callback->(@msg)	321	=item rcv $local_port, $callback->(@msg)
325		322
326	Replaces the callback on the specified miniport (after converting it to	323	Replaces the default callback on the specified port. There is no way to
327	one if required).	324	remove the default callback: use C<sub { }> to disable it, or better
328		325	C<kil> the port when it is no longer needed.
329	=item rcv $port, tagstring => $callback->(@msg), ...
330
331	=item rcv $port, $smartmatch => $callback->(@msg), ...
332
333	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
334
335	Register callbacks to be called on matching messages on the given full
336	port (after converting it to one if required) and return the port.
337
338	The callback has to return a true value when its work is done, after
339	which is will be removed, or a false value in which case it will stay
340	registered.
341		326
342	The global C<$SELF> (exported by this module) contains C<$port> while	327	The global C<$SELF> (exported by this module) contains C<$port> while
343	executing the callback.	328	executing the callback. Runtime errors during callback execution will
		329	result in the port being C<kil>ed.
344		330
345	Runtime errors wdurign callback execution will result in the port being	331	The default callback received all messages not matched by a more specific
346	C<kil>ed.	332	C<tag> match.
347		333
348	If the match is an array reference, then it will be matched against the	334	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
349	first elements of the message, otherwise only the first element is being
350	matched.
351		335
352	Any element in the match that is specified as C<_any_> (a function	336	Register (or replace) callbacks to be called on messages starting with the
353	exported by this module) matches any single element of the message.	337	given tag on the given port (and return the port), or unregister it (when
		338	C<$callback> is C<$undef> or missing). There can only be one callback
		339	registered for each tag.
354		340
355	While not required, it is highly recommended that the first matching	341	The original message will be passed to the callback, after the first
356	element is a string identifying the message. The one-string-only match is	342	element (the tag) has been removed. The callback will use the same
357	also the most efficient match (by far).	343	environment as the default callback (see above).
358		344
359	Example: create a port and bind receivers on it in one go.	345	Example: create a port and bind receivers on it in one go.
360		346
361	my $port = rcv port,	347	my $port = rcv port,
362	msg1 => sub { ...; 0 },	348	msg1 => sub { ... },
363	msg2 => sub { ...; 0 },	349	msg2 => sub { ... },
364	;	350	;
365		351
366	Example: create a port, bind receivers and send it in a message elsewhere	352	Example: create a port, bind receivers and send it in a message elsewhere
367	in one go:	353	in one go:
368		354
369	snd $otherport, reply =>	355	snd $otherport, reply =>
370	rcv port,	356	rcv port,
371	msg1 => sub { ...; 0 },	357	msg1 => sub { ... },
372	...	358	...
373	;	359	;
374		360
		361	Example: temporarily register a rcv callback for a tag matching some port
		362	(e.g. for a rpc reply) and unregister it after a message was received.
		363
		364	rcv $port, $otherport => sub {
		365	my @reply = @_;
		366
		367	rcv $SELF, $otherport;
		368	};
		369
375	=cut	370	=cut
376		371
377	sub rcv($@) {	372	sub rcv($@) {
378	my $port = shift;	373	my $port = shift;
379	my ($noderef, $portid) = split /#/, $port, 2;	374	my ($nodeid, $portid) = split /#/, $port, 2;
380		375
381	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	376	$NODE{$nodeid} == $NODE{""}
382	or Carp::croak "$port: rcv can only be called on local ports, caught";	377	or Carp::croak "$port: rcv can only be called on local ports, caught";
383		378
384	if (@_ == 1) {	379	while (@_) {
		380	if (ref $_[0]) {
		381	if (my $self = $PORT_DATA{$portid}) {
		382	"AnyEvent::MP::Port" eq ref $self
		383	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		384
		385	$self->[2] = shift;
		386	} else {
385	my $cb = shift;	387	my $cb = shift;
386	delete $PORT_DATA{$portid};
387	$PORT{$portid} = sub {	388	$PORT{$portid} = sub {
388	local $SELF = $port;	389	local $SELF = $port;
389	eval {	390	eval { &$cb }; _self_die if $@;
390	&$cb	391	};
391	and kil $port;
392	};	392	}
393	_self_die if $@;	393	} elsif (defined $_[0]) {
394	};
395	} else {
396	my $self = $PORT_DATA{$portid} \|\|= do {	394	my $self = $PORT_DATA{$portid} \|\|= do {
397	my $self = bless {	395	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
398	id => $port,
399	}, "AnyEvent::MP::Port";
400		396
401	$PORT{$portid} = sub {	397	$PORT{$portid} = sub {
402	local $SELF = $port;	398	local $SELF = $port;
403		399
404	eval {
405	for (@{ $self->{rc0}{$_[0]} }) {	400	if (my $cb = $self->[1]{$_[0]}) {
406	$_ && &{$_->[0]}	401	shift;
407	&& undef $_;	402	eval { &$cb }; _self_die if $@;
408	}	403	} else {
409
410	for (@{ $self->{rcv}{$_[0]} }) {
411	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
412	&& &{$_->[0]}	404	&{ $self->[0] };
413	&& undef $_;
414	}
415
416	for (@{ $self->{any} }) {
417	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
418	&& &{$_->[0]}
419	&& undef $_;
420	}	405	}
421	};	406	};
422	_self_die if $@;	407
		408	$self
423	};	409	};
424		410
425	$self
426	};
427
428	"AnyEvent::MP::Port" eq ref $self	411	"AnyEvent::MP::Port" eq ref $self
429	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	412	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
430		413
431	while (@_) {
432	my ($match, $cb) = splice @_, 0, 2;	414	my ($tag, $cb) = splice @_, 0, 2;
433		415
434	if (!ref $match) {	416	if (defined $cb) {
435	push @{ $self->{rc0}{$match} }, [$cb];	417	$self->[1]{$tag} = $cb;
436	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
437	my ($type, @match) = @$match;
438	@match
439	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
440	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
441	} else {	418	} else {
442	push @{ $self->{any} }, [$cb, $match];	419	delete $self->[1]{$tag};
443	}	420	}
444	}	421	}
445	}	422	}
446		423
447	$port	424	$port
…		…
483	$res	460	$res
484	}	461	}
485	}	462	}
486	}	463	}
487		464
488	=item $guard = mon $port, $cb->(@reason)	465	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
489		466
490	=item $guard = mon $port, $rcvport	467	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
491		468
492	=item $guard = mon $port	469	=item $guard = mon $port # kill $SELF when $port dies
493		470
494	=item $guard = mon $port, $rcvport, @msg	471	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
495		472
496	Monitor the given port and do something when the port is killed, and	473	Monitor the given port and do something when the port is killed or
497	optionally return a guard that can be used to stop monitoring again.	474	messages to it were lost, and optionally return a guard that can be used
		475	to stop monitoring again.
		476
		477	C<mon> effectively guarantees that, in the absence of hardware failures,
		478	after starting the monitor, either all messages sent to the port will
		479	arrive, or the monitoring action will be invoked after possible message
		480	loss has been detected. No messages will be lost "in between" (after
		481	the first lost message no further messages will be received by the
		482	port). After the monitoring action was invoked, further messages might get
		483	delivered again.
		484
		485	Note that monitoring-actions are one-shot: once messages are lost (and a
		486	monitoring alert was raised), they are removed and will not trigger again.
498		487
499	In the first form (callback), the callback is simply called with any	488	In the first form (callback), the callback is simply called with any
500	number of C<@reason> elements (no @reason means that the port was deleted	489	number of C<@reason> elements (no @reason means that the port was deleted
501	"normally"). Note also that I<< the callback B<must> never die >>, so use	490	"normally"). Note also that I<< the callback B<must> never die >>, so use
502	C<eval> if unsure.	491	C<eval> if unsure.
503		492
504	In the second form (another port given), the other port (C<$rcvport)	493	In the second form (another port given), the other port (C<$rcvport>)
505	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	494	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
506	"normal" kils nothing happens, while under all other conditions, the other	495	"normal" kils nothing happens, while under all other conditions, the other
507	port is killed with the same reason.	496	port is killed with the same reason.
508		497
509	The third form (kill self) is the same as the second form, except that	498	The third form (kill self) is the same as the second form, except that
510	C<$rvport> defaults to C<$SELF>.	499	C<$rvport> defaults to C<$SELF>.
…		…
513	C<snd>.	502	C<snd>.
514		503
515	As a rule of thumb, monitoring requests should always monitor a port from	504	As a rule of thumb, monitoring requests should always monitor a port from
516	a local port (or callback). The reason is that kill messages might get	505	a local port (or callback). The reason is that kill messages might get
517	lost, just like any other message. Another less obvious reason is that	506	lost, just like any other message. Another less obvious reason is that
518	even monitoring requests can get lost (for exmaple, when the connection	507	even monitoring requests can get lost (for example, when the connection
519	to the other node goes down permanently). When monitoring a port locally	508	to the other node goes down permanently). When monitoring a port locally
520	these problems do not exist.	509	these problems do not exist.
521		510
522	Example: call a given callback when C<$port> is killed.	511	Example: call a given callback when C<$port> is killed.
523		512
…		…
532	mon $port, $self => "restart";	521	mon $port, $self => "restart";
533		522
534	=cut	523	=cut
535		524
536	sub mon {	525	sub mon {
537	my ($noderef, $port) = split /#/, shift, 2;	526	my ($nodeid, $port) = split /#/, shift, 2;
538		527
539	my $node = $NODE{$noderef} \|\| add_node $noderef;	528	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
540		529
541	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	530	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
542		531
543	unless (ref $cb) {	532	unless (ref $cb) {
544	if (@_) {	533	if (@_) {
545	# send a kill info message	534	# send a kill info message
546	my (@msg) = @_;	535	my (@msg) = ($cb, @_);
547	$cb = sub { snd @msg, @_ };	536	$cb = sub { snd @msg, @_ };
548	} else {	537	} else {
549	# simply kill other port	538	# simply kill other port
550	my $port = $cb;	539	my $port = $cb;
551	$cb = sub { kil $port, @_ if @_ };	540	$cb = sub { kil $port, @_ if @_ };
…		…
564	is killed, the references will be freed.	553	is killed, the references will be freed.
565		554
566	Optionally returns a guard that will stop the monitoring.	555	Optionally returns a guard that will stop the monitoring.
567		556
568	This function is useful when you create e.g. timers or other watchers and	557	This function is useful when you create e.g. timers or other watchers and
569	want to free them when the port gets killed:	558	want to free them when the port gets killed (note the use of C<psub>):
570		559
571	$port->rcv (start => sub {	560	$port->rcv (start => sub {
572	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	561	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
573	undef $timer if 0.9 < rand;	562	undef $timer if 0.9 < rand;
574	});	563	});
575	});	564	});
576		565
577	=cut	566	=cut
…		…
586		575
587	=item kil $port[, @reason]	576	=item kil $port[, @reason]
588		577
589	Kill the specified port with the given C<@reason>.	578	Kill the specified port with the given C<@reason>.
590		579
591	If no C<@reason> is specified, then the port is killed "normally" (linked	580	If no C<@reason> is specified, then the port is killed "normally" (ports
592	ports will not be kileld, or even notified).	581	monitoring other ports will not necessarily die because a port dies
		582	"normally").
593		583
594	Otherwise, linked ports get killed with the same reason (second form of	584	Otherwise, linked ports get killed with the same reason (second form of
595	C<mon>, see below).	585	C<mon>, see above).
596		586
597	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	587	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
598	will be reported as reason C<< die => $@ >>.	588	will be reported as reason C<< die => $@ >>.
599		589
600	Transport/communication errors are reported as C<< transport_error =>	590	Transport/communication errors are reported as C<< transport_error =>
601	$message >>.	591	$message >>.
602		592
603	=back
604
605	=head1 NODE MESSAGES
606
607	Nodes understand the following messages sent to them. Many of them take
608	arguments called C<@reply>, which will simply be used to compose a reply
609	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
610	the remaining arguments are simply the message data.
611
612	While other messages exist, they are not public and subject to change.
613
614	=over 4
615
616	=cut	593	=cut
617		594
618	=item lookup => $name, @reply	595	=item $port = spawn $node, $initfunc[, @initdata]
619		596
620	Replies with the port ID of the specified well-known port, or C<undef>.	597	Creates a port on the node C<$node> (which can also be a port ID, in which
		598	case it's the node where that port resides).
621		599
622	=item devnull => ...	600	The port ID of the newly created port is returned immediately, and it is
		601	possible to immediately start sending messages or to monitor the port.
623		602
624	Generic data sink/CPU heat conversion.	603	After the port has been created, the init function is called on the remote
		604	node, in the same context as a C<rcv> callback. This function must be a
		605	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		606	specify a function in the main program, use C<::name>.
625		607
626	=item relay => $port, @msg	608	If the function doesn't exist, then the node tries to C<require>
		609	the package, then the package above the package and so on (e.g.
		610	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		611	exists or it runs out of package names.
627		612
628	Simply forwards the message to the given port.	613	The init function is then called with the newly-created port as context
		614	object (C<$SELF>) and the C<@initdata> values as arguments.
629		615
630	=item eval => $string[ @reply]	616	A common idiom is to pass a local port, immediately monitor the spawned
		617	port, and in the remote init function, immediately monitor the passed
		618	local port. This two-way monitoring ensures that both ports get cleaned up
		619	when there is a problem.
631		620
632	Evaluates the given string. If C<@reply> is given, then a message of the	621	Example: spawn a chat server port on C<$othernode>.
633	form C<@reply, $@, @evalres> is sent.
634		622
635	Example: crash another node.	623	# this node, executed from within a port context:
		624	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		625	mon $server;
636		626
637	snd $othernode, eval => "exit";	627	# init function on C<$othernode>
		628	sub connect {
		629	my ($srcport) = @_;
638		630
639	=item time => @reply	631	mon $srcport;
640		632
641	Replies the the current node time to C<@reply>.	633	rcv $SELF, sub {
		634	...
		635	};
		636	}
642		637
643	Example: tell the current node to send the current time to C<$myport> in a	638	=cut
644	C<timereply> message.
645		639
646	snd $NODE, time => $myport, timereply => 1, 2;	640	sub _spawn {
647	# => snd $myport, timereply => 1, 2, <time>	641	my $port = shift;
		642	my $init = shift;
		643
		644	local $SELF = "$NODE#$port";
		645	eval {
		646	&{ load_func $init }
		647	};
		648	_self_die if $@;
		649	}
		650
		651	sub spawn(@) {
		652	my ($nodeid, undef) = split /#/, shift, 2;
		653
		654	my $id = "$RUNIQ." . $ID++;
		655
		656	$_[0] =~ /::/
		657	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		658
		659	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
		660
		661	"$nodeid#$id"
		662	}
		663
		664	=item after $timeout, @msg
		665
		666	=item after $timeout, $callback
		667
		668	Either sends the given message, or call the given callback, after the
		669	specified number of seconds.
		670
		671	This is simply a utility function that comes in handy at times - the
		672	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		673	so it may go away in the future.
		674
		675	=cut
		676
		677	sub after($@) {
		678	my ($timeout, @action) = @_;
		679
		680	my $t; $t = AE::timer $timeout, 0, sub {
		681	undef $t;
		682	ref $action[0]
		683	? $action[0]()
		684	: snd @action;
		685	};
		686	}
648		687
649	=back	688	=back
650		689
651	=head1 AnyEvent::MP vs. Distributed Erlang	690	=head1 AnyEvent::MP vs. Distributed Erlang
652		691
…		…
662		701
663	Despite the similarities, there are also some important differences:	702	Despite the similarities, there are also some important differences:
664		703
665	=over 4	704	=over 4
666		705
667	=item * Node references contain the recipe on how to contact them.	706	=item * Node IDs are arbitrary strings in AEMP.
668		707
669	Erlang relies on special naming and DNS to work everywhere in the	708	Erlang relies on special naming and DNS to work everywhere in the same
670	same way. AEMP relies on each node knowing it's own address(es), with	709	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
671	convenience functionality.	710	configuration or DNS), but will otherwise discover other odes itself.
672		711
673	This means that AEMP requires a less tightly controlled environment at the	712	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
674	cost of longer node references and a slightly higher management overhead.	713	uses "local ports are like remote ports".
		714
		715	The failure modes for local ports are quite different (runtime errors
		716	only) then for remote ports - when a local port dies, you I<know> it dies,
		717	when a connection to another node dies, you know nothing about the other
		718	port.
		719
		720	Erlang pretends remote ports are as reliable as local ports, even when
		721	they are not.
		722
		723	AEMP encourages a "treat remote ports differently" philosophy, with local
		724	ports being the special case/exception, where transport errors cannot
		725	occur.
675		726
676	=item * Erlang uses processes and a mailbox, AEMP does not queue.	727	=item * Erlang uses processes and a mailbox, AEMP does not queue.
677		728
678	Erlang uses processes that selctively receive messages, and therefore	729	Erlang uses processes that selectively receive messages, and therefore
679	needs a queue. AEMP is event based, queuing messages would serve no useful	730	needs a queue. AEMP is event based, queuing messages would serve no
680	purpose.	731	useful purpose. For the same reason the pattern-matching abilities of
		732	AnyEvent::MP are more limited, as there is little need to be able to
		733	filter messages without dequeuing them.
681		734
682	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	735	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
683		736
684	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	737	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
685		738
686	Sending messages in Erlang is synchronous and blocks the process. AEMP	739	Sending messages in Erlang is synchronous and blocks the process (and
687	sends are immediate, connection establishment is handled in the	740	so does not need a queue that can overflow). AEMP sends are immediate,
688	background.	741	connection establishment is handled in the background.
689		742
690	=item * Erlang can silently lose messages, AEMP cannot.	743	=item * Erlang suffers from silent message loss, AEMP does not.
691		744
692	Erlang makes few guarantees on messages delivery - messages can get lost	745	Erlang makes few guarantees on messages delivery - messages can get lost
693	without any of the processes realising it (i.e. you send messages a, b,	746	without any of the processes realising it (i.e. you send messages a, b,
694	and c, and the other side only receives messages a and c).	747	and c, and the other side only receives messages a and c).
695		748
696	AEMP guarantees correct ordering, and the guarantee that there are no	749	AEMP guarantees correct ordering, and the guarantee that after one message
697	holes in the message sequence.	750	is lost, all following ones sent to the same port are lost as well, until
698		751	monitoring raises an error, so there are no silent "holes" in the message
699	=item * In Erlang, processes can be declared dead and later be found to be	752	sequence.
700	alive.
701
702	In Erlang it can happen that a monitored process is declared dead and
703	linked processes get killed, but later it turns out that the process is
704	still alive - and can receive messages.
705
706	In AEMP, when port monitoring detects a port as dead, then that port will
707	eventually be killed - it cannot happen that a node detects a port as dead
708	and then later sends messages to it, finding it is still alive.
709		753
710	=item * Erlang can send messages to the wrong port, AEMP does not.	754	=item * Erlang can send messages to the wrong port, AEMP does not.
711		755
712	In Erlang it is quite possible that a node that restarts reuses a process	756	In Erlang it is quite likely that a node that restarts reuses a process ID
713	ID known to other nodes for a completely different process, causing	757	known to other nodes for a completely different process, causing messages
714	messages destined for that process to end up in an unrelated process.	758	destined for that process to end up in an unrelated process.
715		759
716	AEMP never reuses port IDs, so old messages or old port IDs floating	760	AEMP never reuses port IDs, so old messages or old port IDs floating
717	around in the network will not be sent to an unrelated port.	761	around in the network will not be sent to an unrelated port.
718		762
719	=item * Erlang uses unprotected connections, AEMP uses secure	763	=item * Erlang uses unprotected connections, AEMP uses secure
720	authentication and can use TLS.	764	authentication and can use TLS.
721		765
722	AEMP can use a proven protocol - SSL/TLS - to protect connections and	766	AEMP can use a proven protocol - TLS - to protect connections and
723	securely authenticate nodes.	767	securely authenticate nodes.
724		768
725	=item * The AEMP protocol is optimised for both text-based and binary	769	=item * The AEMP protocol is optimised for both text-based and binary
726	communications.	770	communications.
727		771
728	The AEMP protocol, unlike the Erlang protocol, supports both	772	The AEMP protocol, unlike the Erlang protocol, supports both programming
729	language-independent text-only protocols (good for debugging) and binary,	773	language independent text-only protocols (good for debugging) and binary,
730	language-specific serialisers (e.g. Storable).	774	language-specific serialisers (e.g. Storable). By default, unless TLS is
		775	used, the protocol is actually completely text-based.
731		776
732	It has also been carefully designed to be implementable in other languages	777	It has also been carefully designed to be implementable in other languages
733	with a minimum of work while gracefully degrading fucntionality to make the	778	with a minimum of work while gracefully degrading functionality to make the
734	protocol simple.	779	protocol simple.
735		780
736	=item * AEMP has more flexible monitoring options than Erlang.	781	=item * AEMP has more flexible monitoring options than Erlang.
737		782
738	In Erlang, you can chose to receive I<all> exit signals as messages	783	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
741	Erlang, as one can choose between automatic kill, exit message or callback	786	Erlang, as one can choose between automatic kill, exit message or callback
742	on a per-process basis.	787	on a per-process basis.
743		788
744	=item * Erlang tries to hide remote/local connections, AEMP does not.	789	=item * Erlang tries to hide remote/local connections, AEMP does not.
745		790
746	Monitoring in Erlang is not an indicator of process death/crashes,	791	Monitoring in Erlang is not an indicator of process death/crashes, in the
747	as linking is (except linking is unreliable in Erlang).	792	same way as linking is (except linking is unreliable in Erlang).
748		793
749	In AEMP, you don't "look up" registered port names or send to named ports	794	In AEMP, you don't "look up" registered port names or send to named ports
750	that might or might not be persistent. Instead, you normally spawn a port	795	that might or might not be persistent. Instead, you normally spawn a port
751	on the remote node. The init function monitors the you, and you monitor	796	on the remote node. The init function monitors you, and you monitor the
752	the remote port. Since both monitors are local to the node, they are much	797	remote port. Since both monitors are local to the node, they are much more
753	more reliable.	798	reliable (no need for C<spawn_link>).
754		799
755	This also saves round-trips and avoids sending messages to the wrong port	800	This also saves round-trips and avoids sending messages to the wrong port
756	(hard to do in Erlang).	801	(hard to do in Erlang).
757		802
758	=back	803	=back
759		804
		805	=head1 RATIONALE
		806
		807	=over 4
		808
		809	=item Why strings for port and node IDs, why not objects?
		810
		811	We considered "objects", but found that the actual number of methods
		812	that can be called are quite low. Since port and node IDs travel over
		813	the network frequently, the serialising/deserialising would add lots of
		814	overhead, as well as having to keep a proxy object everywhere.
		815
		816	Strings can easily be printed, easily serialised etc. and need no special
		817	procedures to be "valid".
		818
		819	And as a result, a miniport consists of a single closure stored in a
		820	global hash - it can't become much cheaper.
		821
		822	=item Why favour JSON, why not a real serialising format such as Storable?
		823
		824	In fact, any AnyEvent::MP node will happily accept Storable as framing
		825	format, but currently there is no way to make a node use Storable by
		826	default (although all nodes will accept it).
		827
		828	The default framing protocol is JSON because a) JSON::XS is many times
		829	faster for small messages and b) most importantly, after years of
		830	experience we found that object serialisation is causing more problems
		831	than it solves: Just like function calls, objects simply do not travel
		832	easily over the network, mostly because they will always be a copy, so you
		833	always have to re-think your design.
		834
		835	Keeping your messages simple, concentrating on data structures rather than
		836	objects, will keep your messages clean, tidy and efficient.
		837
		838	=back
		839
760	=head1 SEE ALSO	840	=head1 SEE ALSO
		841
		842	L<AnyEvent::MP::Intro> - a gentle introduction.
		843
		844	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		845
		846	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		847	your applications.
761		848
762	L<AnyEvent>.	849	L<AnyEvent>.
763		850
764	=head1 AUTHOR	851	=head1 AUTHOR
765		852

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC vs. Revision 1.77 by elmex, Thu Sep 3 07:57:30 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC vs.
Revision 1.77 by elmex, Thu Sep 3 07:57:30 2009 UTC