[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 1.75 by root, Mon Aug 31 13:18:06 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 - uptodate, but incomplete.
		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		59
43	At the moment, this module family is severly broken and underdocumented,	60	At the moment, this module family is a bit 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		61
47	=head1 CONCEPTS	62	=head1 CONCEPTS
48		63
49	=over 4	64	=over 4
50		65
51	=item port	66	=item port
52		67
53	A port is something you can send messages to (with the C<snd> function).	68	A port is something you can send messages to (with the C<snd> function).
54		69
55	Some ports allow you to register C<rcv> handlers that can match specific	70	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	71	some messages. Messages send to ports will not be queued, regardless of
57	will not be queued.	72	anything was listening for them or not.
58		73
59	=item port id - C<noderef#portname>	74	=item port ID - C<nodeid#portname>
60		75
61	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as	76	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	77	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		78
66	=item node	79	=item node
67		80
68	A node is a single process containing at least one port - the node	81	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	82	which enables nodes to manage each other remotely, and to create new
70	create new ports, among other things.	83	ports.
71		84
72	Nodes are either private (single-process only), slaves (connected to a	85	Nodes are either public (have one or more listening ports) or private
73	master node only) or public nodes (connectable from unrelated nodes).	86	(no listening ports). Private nodes cannot talk to other private nodes
		87	currently.
74		88
75	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	89	=item node ID - C<[a-za-Z0-9_\-.:]+>
76		90
77	A node reference is a string that either simply identifies the node (for	91	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	92	network. Depending on the configuration used, node IDs can look like a
79	node (for public nodes).	93	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
		94	doesn't interpret node IDs in any way.
80		95
81	This recipe is simply a comma-separated list of C<address:port> pairs (for	96	=item binds - C<ip:port>
82	TCP/IP, other protocols might look different).
83		97
84	Node references come in two flavours: resolved (containing only numerical	98	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).	99	each other. To do this, nodes should listen on one or more local transport
		100	endpoints - binds. Currently, only standard C<ip:port> specifications can
		101	be used, which specify TCP ports to listen on.
86		102
87	Before using an unresolved node reference in a message you first have to	103	=item seeds - C<host:port>
88	resolve it.	104
		105	When a node starts, it knows nothing about the network. To teach the node
		106	about the network it first has to contact some other node within the
		107	network. This node is called a seed.
		108
		109	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes
		110	are expected to be long-running, and at least one of those should always
		111	be available. When nodes run out of connections (e.g. due to a network
		112	error), they try to re-establish connections to some seednodes again to
		113	join the network.
		114
		115	Apart from being sued for seeding, seednodes are not special in any way -
		116	every public node can be a seednode.
89		117
90	=back	118	=back
91		119
92	=head1 VARIABLES/FUNCTIONS	120	=head1 VARIABLES/FUNCTIONS
93		121
…		…
95		123
96	=cut	124	=cut
97		125
98	package AnyEvent::MP;	126	package AnyEvent::MP;
99		127
100	use AnyEvent::MP::Base;	128	use AnyEvent::MP::Kernel;
101		129
102	use common::sense;	130	use common::sense;
103		131
104	use Carp ();	132	use Carp ();
105		133
106	use AE ();	134	use AE ();
107		135
108	use base "Exporter";	136	use base "Exporter";
109		137
110	our $VERSION = '0.1';	138	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
		139
111	our @EXPORT = qw(	140	our @EXPORT = qw(
112	NODE $NODE *SELF node_of _any_	141	NODE $NODE *SELF node_of after
113	resolve_node initialise_node	142	configure
114	snd rcv mon kil reg psub	143	snd rcv mon mon_guard kil reg psub spawn
115	port	144	port
116	);	145	);
117		146
118	our $SELF;	147	our $SELF;
119		148
…		…
123	kil $SELF, die => $msg;	152	kil $SELF, die => $msg;
124	}	153	}
125		154
126	=item $thisnode = NODE / $NODE	155	=item $thisnode = NODE / $NODE
127		156
128	The C<NODE> function returns, and the C<$NODE> variable contains	157	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	158	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	159	a call to C<configure>.
131	identifiers become invalid.
132		160
133	=item $noderef = node_of $port	161	=item $nodeid = node_of $port
134		162
135	Extracts and returns the noderef from a portid or a noderef.	163	Extracts and returns the node ID from a port ID or a node ID.
136		164
137	=item initialise_node $noderef, $seednode, $seednode...	165	=item configure key => value...
138		166
139	=item initialise_node "slave/", $master, $master...
140
141	Before a node can talk to other nodes on the network it has to initialise	167	Before a node can talk to other nodes on the network (i.e. enter
142	itself - the minimum a node needs to know is it's own name, and optionally	168	"distributed mode") it has to configure itself - the minimum a node needs
143	it should know the noderefs of some other nodes in the network.	169	to know is its own name, and optionally it should know the addresses of
		170	some other nodes in the network to discover other nodes.
144		171
145	This function initialises a node - it must be called exactly once (or	172	This function configures a node - it must be called exactly once (or
146	never) before calling other AnyEvent::MP functions.	173	never) before calling other AnyEvent::MP functions.
147		174
148	All arguments are noderefs, which can be either resolved or unresolved.
149
150	There are two types of networked nodes, public nodes and slave nodes:
151
152	=over 4	175	=over 4
153		176
154	=item public nodes	177	=item step 1, gathering configuration from profiles
155		178
156	For public nodes, C<$noderef> must either be a (possibly unresolved)	179	The function first looks up a profile in the aemp configuration (see the
157	noderef, in which case it will be resolved, or C<undef> (or missing), in	180	L<aemp> commandline utility). The profile name can be specified via the
158	which case the noderef will be guessed.	181	named C<profile> parameter. If it is missing, then the nodename (F<uname
		182	-n>) will be used as profile name.
159		183
160	Afterwards, the node will bind itself on all endpoints and try to connect	184	The profile data is then gathered as follows:
161	to all additional C<$seednodes> that are specified. Seednodes are optional
162	and can be used to quickly bootstrap the node into an existing network.
163		185
164	=item slave nodes	186	First, all remaining key => value pairs (all of which are conviniently
		187	undocumented at the moment) will be interpreted as configuration
		188	data. Then they will be overwritten by any values specified in the global
		189	default configuration (see the F<aemp> utility), then the chain of
		190	profiles chosen by the profile name (and any C<parent> attributes).
165		191
166	When the C<$noderef> is the special string C<slave/>, then the node will	192	That means that the values specified in the profile have highest priority
167	become a slave node. Slave nodes cannot be contacted from outside and will	193	and the values specified directly via C<configure> have lowest priority,
168	route most of their traffic to the master node that they attach to.	194	and can only be used to specify defaults.
169		195
170	At least one additional noderef is required: The node will try to connect	196	If the profile specifies a node ID, then this will become the node ID of
171	to all of them and will become a slave attached to the first node it can	197	this process. If not, then the profile name will be used as node ID. The
172	successfully connect to.	198	special node ID of C<anon/> will be replaced by a random node ID.
		199
		200	=item step 2, bind listener sockets
		201
		202	The next step is to look up the binds in the profile, followed by binding
		203	aemp protocol listeners on all binds specified (it is possible and valid
		204	to have no binds, meaning that the node cannot be contacted form the
		205	outside. This means the node cannot talk to other nodes that also have no
		206	binds, but it can still talk to all "normal" nodes).
		207
		208	If the profile does not specify a binds list, then a default of C<*> is
		209	used, meaning the node will bind on a dynamically-assigned port on every
		210	local IP address it finds.
		211
		212	=item step 3, connect to seed nodes
		213
		214	As the last step, the seeds list from the profile is passed to the
		215	L<AnyEvent::MP::Global> module, which will then use it to keep
		216	connectivity with at least one node at any point in time.
173		217
174	=back	218	=back
175		219
176	This function will block until all nodes have been resolved and, for slave	220	Example: become a distributed node using the locla node name as profile.
177	nodes, until it has successfully established a connection to a master	221	This should be the most common form of invocation for "daemon"-type nodes.
178	server.
179		222
180	Example: become a public node listening on the default node.	223	configure
181		224
182	initialise_node;	225	Example: become an anonymous node. This form is often used for commandline
		226	clients.
183		227
184	Example: become a public node, and try to contact some well-known master	228	configure nodeid => "anon/";
185	servers to become part of the network.
186		229
187	initialise_node undef, "master1", "master2";	230	Example: configure a node using a profile called seed, which si suitable
		231	for a seed node as it binds on all local addresses on a fixed port (4040,
		232	customary for aemp).
188		233
189	Example: become a public node listening on port C<4041>.	234	# use the aemp commandline utility
		235	# aemp profile seed nodeid anon/ binds '*:4040'
190		236
191	initialise_node 4041;	237	# then use it
		238	configure profile => "seed";
192		239
193	Example: become a public node, only visible on localhost port 4044.	240	# or simply use aemp from the shell again:
		241	# aemp run profile seed
194		242
195	initialise_node "locahost:4044";	243	# or provide a nicer-to-remember nodeid
196		244	# 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		245
230	=item $SELF	246	=item $SELF
231		247
232	Contains the current port id while executing C<rcv> callbacks or C<psub>	248	Contains the current port id while executing C<rcv> callbacks or C<psub>
233	blocks.	249	blocks.
234		250
235	=item SELF, %SELF, @SELF...	251	=item *SELF, SELF, %SELF, @SELF...
236		252
237	Due to some quirks in how perl exports variables, it is impossible to	253	Due to some quirks in how perl exports variables, it is impossible to
238	just export C<$SELF>, all the symbols called C<SELF> are exported by this	254	just export C<$SELF>, all the symbols named C<SELF> are exported by this
239	module, but only C<$SELF> is currently used.	255	module, but only C<$SELF> is currently used.
240		256
241	=item snd $port, type => @data	257	=item snd $port, type => @data
242		258
243	=item snd $port, @msg	259	=item snd $port, @msg
244		260
245	Send the given message to the given port ID, which can identify either	261	Send the given message to the given port, which can identify either a
246	a local or a remote port, and can be either a string or soemthignt hat	262	local or a remote port, and must be a port ID.
247	stringifies a sa port ID (such as a port object :).
248		263
249	While the message can be about anything, it is highly recommended to use a	264	While the message can be almost anything, it is highly recommended to
250	string as first element (a portid, or some word that indicates a request	265	use a string as first element (a port ID, or some word that indicates a
251	type etc.).	266	request type etc.) and to consist if only simple perl values (scalars,
		267	arrays, hashes) - if you think you need to pass an object, think again.
252		268
253	The message data effectively becomes read-only after a call to this	269	The message data logically becomes read-only after a call to this
254	function: modifying any argument is not allowed and can cause many	270	function: modifying any argument (or values referenced by them) is
255	problems.	271	forbidden, as there can be considerable time between the call to C<snd>
		272	and the time the message is actually being serialised - in fact, it might
		273	never be copied as within the same process it is simply handed to the
		274	receiving port.
256		275
257	The type of data you can transfer depends on the transport protocol: when	276	The type of data you can transfer depends on the transport protocol: when
258	JSON is used, then only strings, numbers and arrays and hashes consisting	277	JSON is used, then only strings, numbers and arrays and hashes consisting
259	of those are allowed (no objects). When Storable is used, then anything	278	of those are allowed (no objects). When Storable is used, then anything
260	that Storable can serialise and deserialise is allowed, and for the local	279	that Storable can serialise and deserialise is allowed, and for the local
261	node, anything can be passed.	280	node, anything can be passed. Best rely only on the common denominator of
		281	these.
262		282
263	=item $local_port = port	283	=item $local_port = port
264		284
265	Create a new local port object that can be used either as a pattern	285	Create a new local port object and returns its port ID. Initially it has
266	matching port ("full port") or a single-callback port ("miniport"),	286	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		287
269	=item $port = port { my @msg = @_; $finished }	288	=item $local_port = port { my @msg = @_ }
270		289
271	Creates a "miniport", that is, a very lightweight port without any pattern	290	Creates a new local port, and returns its ID. Semantically the same as
272	matching behind it, and returns its ID. Semantically the same as creating
273	a port and calling C<rcv $port, $callback> on it.	291	creating a port and calling C<rcv $port, $callback> on it.
274		292
275	The block will be called for every message received on the port. When the	293	The block will be called for every message received on the port, with the
276	callback returns a true value its job is considered "done" and the port	294	global variable C<$SELF> set to the port ID. Runtime errors will cause the
277	will be destroyed. Otherwise it will stay alive.	295	port to be C<kil>ed. The message will be passed as-is, no extra argument
		296	(i.e. no port ID) will be passed to the callback.
278		297
279	The message will be passed as-is, no extra argument (i.e. no port id) will	298	If you want to stop/destroy the port, simply C<kil> it:
280	be passed to the callback.
281		299
282	If you need the local port id in the callback, this works nicely:	300	my $port = port {
283		301	my @msg = @_;
284	my $port; $port = port {	302	...
285	snd $otherport, reply => $port;	303	kil $SELF;
286	};	304	};
287		305
288	=cut	306	=cut
289		307
290	sub rcv($@);	308	sub rcv($@);
		309
		310	sub _kilme {
		311	die "received message on port without callback";
		312	}
291		313
292	sub port(;&) {	314	sub port(;&) {
293	my $id = "$UNIQ." . $ID++;	315	my $id = "$UNIQ." . $ID++;
294	my $port = "$NODE#$id";	316	my $port = "$NODE#$id";
295		317
296	if (@_) {	318	rcv $port, shift \|\| \&_kilme;
297	rcv $port, shift;
298	} else {
299	$PORT{$id} = sub { }; # nop
300	}
301		319
302	$port	320	$port
303	}	321	}
304		322
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)	323	=item rcv $local_port, $callback->(@msg)
325		324
326	Replaces the callback on the specified miniport (after converting it to	325	Replaces the default callback on the specified port. There is no way to
327	one if required).	326	remove the default callback: use C<sub { }> to disable it, or better
328		327	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...] => $callback->(@msg), ...
334
335	Register callbacks to be called on matching messages on the given full
336	port (after converting it to one if required) and return the port.
337
338	The callback has to return a true value when its work is done, after
339	which is will be removed, or a false value in which case it will stay
340	registered.
341		328
342	The global C<$SELF> (exported by this module) contains C<$port> while	329	The global C<$SELF> (exported by this module) contains C<$port> while
343	executing the callback.	330	executing the callback. Runtime errors during callback execution will
		331	result in the port being C<kil>ed.
344		332
345	Runtime errors wdurign callback execution will result in the port being	333	The default callback received all messages not matched by a more specific
346	C<kil>ed.	334	C<tag> match.
347		335
348	If the match is an array reference, then it will be matched against the	336	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
349	first elements of the message, otherwise only the first element is being
350	matched.
351		337
352	Any element in the match that is specified as C<_any_> (a function	338	Register (or replace) callbacks to be called on messages starting with the
353	exported by this module) matches any single element of the message.	339	given tag on the given port (and return the port), or unregister it (when
		340	C<$callback> is C<$undef> or missing). There can only be one callback
		341	registered for each tag.
354		342
355	While not required, it is highly recommended that the first matching	343	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	344	element (the tag) has been removed. The callback will use the same
357	also the most efficient match (by far).	345	environment as the default callback (see above).
358		346
359	Example: create a port and bind receivers on it in one go.	347	Example: create a port and bind receivers on it in one go.
360		348
361	my $port = rcv port,	349	my $port = rcv port,
362	msg1 => sub { ...; 0 },	350	msg1 => sub { ... },
363	msg2 => sub { ...; 0 },	351	msg2 => sub { ... },
364	;	352	;
365		353
366	Example: create a port, bind receivers and send it in a message elsewhere	354	Example: create a port, bind receivers and send it in a message elsewhere
367	in one go:	355	in one go:
368		356
369	snd $otherport, reply =>	357	snd $otherport, reply =>
370	rcv port,	358	rcv port,
371	msg1 => sub { ...; 0 },	359	msg1 => sub { ... },
372	...	360	...
373	;	361	;
374		362
		363	Example: temporarily register a rcv callback for a tag matching some port
		364	(e.g. for a rpc reply) and unregister it after a message was received.
		365
		366	rcv $port, $otherport => sub {
		367	my @reply = @_;
		368
		369	rcv $SELF, $otherport;
		370	};
		371
375	=cut	372	=cut
376		373
377	sub rcv($@) {	374	sub rcv($@) {
378	my $port = shift;	375	my $port = shift;
379	my ($noderef, $portid) = split /#/, $port, 2;	376	my ($nodeid, $portid) = split /#/, $port, 2;
380		377
381	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	378	$NODE{$nodeid} == $NODE{""}
382	or Carp::croak "$port: rcv can only be called on local ports, caught";	379	or Carp::croak "$port: rcv can only be called on local ports, caught";
383		380
384	if (@_ == 1) {	381	while (@_) {
		382	if (ref $_[0]) {
		383	if (my $self = $PORT_DATA{$portid}) {
		384	"AnyEvent::MP::Port" eq ref $self
		385	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		386
		387	$self->[2] = shift;
		388	} else {
385	my $cb = shift;	389	my $cb = shift;
386	delete $PORT_DATA{$portid};
387	$PORT{$portid} = sub {	390	$PORT{$portid} = sub {
388	local $SELF = $port;	391	local $SELF = $port;
389	eval {	392	eval { &$cb }; _self_die if $@;
390	&$cb	393	};
391	and kil $port;
392	};	394	}
393	_self_die if $@;	395	} elsif (defined $_[0]) {
394	};
395	} else {
396	my $self = $PORT_DATA{$portid} \|\|= do {	396	my $self = $PORT_DATA{$portid} \|\|= do {
397	my $self = bless {	397	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
398	id => $port,
399	}, "AnyEvent::MP::Port";
400		398
401	$PORT{$portid} = sub {	399	$PORT{$portid} = sub {
402	local $SELF = $port;	400	local $SELF = $port;
403		401
404	eval {
405	for (@{ $self->{rc0}{$_[0]} }) {	402	if (my $cb = $self->[1]{$_[0]}) {
406	$_ && &{$_->[0]}	403	shift;
407	&& undef $_;	404	eval { &$cb }; _self_die if $@;
408	}	405	} else {
409
410	for (@{ $self->{rcv}{$_[0]} }) {
411	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
412	&& &{$_->[0]}	406	&{ $self->[0] };
413	&& undef $_;
414	}
415
416	for (@{ $self->{any} }) {
417	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
418	&& &{$_->[0]}
419	&& undef $_;
420	}	407	}
421	};	408	};
422	_self_die if $@;	409
		410	$self
423	};	411	};
424		412
425	$self
426	};
427
428	"AnyEvent::MP::Port" eq ref $self	413	"AnyEvent::MP::Port" eq ref $self
429	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
430		415
431	while (@_) {
432	my ($match, $cb) = splice @_, 0, 2;	416	my ($tag, $cb) = splice @_, 0, 2;
433		417
434	if (!ref $match) {	418	if (defined $cb) {
435	push @{ $self->{rc0}{$match} }, [$cb];	419	$self->[1]{$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 {	420	} else {
442	push @{ $self->{any} }, [$cb, $match];	421	delete $self->[1]{$tag};
443	}	422	}
444	}	423	}
445	}	424	}
446		425
447	$port	426	$port
…		…
483	$res	462	$res
484	}	463	}
485	}	464	}
486	}	465	}
487		466
488	=item $guard = mon $port, $cb->(@reason)	467	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
489		468
490	=item $guard = mon $port, $rcvport	469	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
491		470
492	=item $guard = mon $port	471	=item $guard = mon $port # kill $SELF when $port dies
493		472
494	=item $guard = mon $port, $rcvport, @msg	473	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
495		474
496	Monitor the given port and do something when the port is killed, and	475	Monitor the given port and do something when the port is killed or
497	optionally return a guard that can be used to stop monitoring again.	476	messages to it were lost, and optionally return a guard that can be used
		477	to stop monitoring again.
		478
		479	C<mon> effectively guarantees that, in the absence of hardware failures,
		480	after starting the monitor, either all messages sent to the port will
		481	arrive, or the monitoring action will be invoked after possible message
		482	loss has been detected. No messages will be lost "in between" (after
		483	the first lost message no further messages will be received by the
		484	port). After the monitoring action was invoked, further messages might get
		485	delivered again.
		486
		487	Note that monitoring-actions are one-shot: once messages are lost (and a
		488	monitoring alert was raised), they are removed and will not trigger again.
498		489
499	In the first form (callback), the callback is simply called with any	490	In the first form (callback), the callback is simply called with any
500	number of C<@reason> elements (no @reason means that the port was deleted	491	number of C<@reason> elements (no @reason means that the port was deleted
501	"normally"). Note also that I<< the callback B<must> never die >>, so use	492	"normally"). Note also that I<< the callback B<must> never die >>, so use
502	C<eval> if unsure.	493	C<eval> if unsure.
503		494
504	In the second form (another port given), the other port (C<$rcvport)	495	In the second form (another port given), the other port (C<$rcvport>)
505	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	496	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
506	"normal" kils nothing happens, while under all other conditions, the other	497	"normal" kils nothing happens, while under all other conditions, the other
507	port is killed with the same reason.	498	port is killed with the same reason.
508		499
509	The third form (kill self) is the same as the second form, except that	500	The third form (kill self) is the same as the second form, except that
…		…
532	mon $port, $self => "restart";	523	mon $port, $self => "restart";
533		524
534	=cut	525	=cut
535		526
536	sub mon {	527	sub mon {
537	my ($noderef, $port) = split /#/, shift, 2;	528	my ($nodeid, $port) = split /#/, shift, 2;
538		529
539	my $node = $NODE{$noderef} \|\| add_node $noderef;	530	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
540		531
541	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	532	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
542		533
543	unless (ref $cb) {	534	unless (ref $cb) {
544	if (@_) {	535	if (@_) {
545	# send a kill info message	536	# send a kill info message
546	my (@msg) = @_;	537	my (@msg) = ($cb, @_);
547	$cb = sub { snd @msg, @_ };	538	$cb = sub { snd @msg, @_ };
548	} else {	539	} else {
549	# simply kill other port	540	# simply kill other port
550	my $port = $cb;	541	my $port = $cb;
551	$cb = sub { kil $port, @_ if @_ };	542	$cb = sub { kil $port, @_ if @_ };
…		…
564	is killed, the references will be freed.	555	is killed, the references will be freed.
565		556
566	Optionally returns a guard that will stop the monitoring.	557	Optionally returns a guard that will stop the monitoring.
567		558
568	This function is useful when you create e.g. timers or other watchers and	559	This function is useful when you create e.g. timers or other watchers and
569	want to free them when the port gets killed:	560	want to free them when the port gets killed (note the use of C<psub>):
570		561
571	$port->rcv (start => sub {	562	$port->rcv (start => sub {
572	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	563	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
573	undef $timer if 0.9 < rand;	564	undef $timer if 0.9 < rand;
574	});	565	});
575	});	566	});
576		567
577	=cut	568	=cut
…		…
586		577
587	=item kil $port[, @reason]	578	=item kil $port[, @reason]
588		579
589	Kill the specified port with the given C<@reason>.	580	Kill the specified port with the given C<@reason>.
590		581
591	If no C<@reason> is specified, then the port is killed "normally" (linked	582	If no C<@reason> is specified, then the port is killed "normally" (ports
592	ports will not be kileld, or even notified).	583	monitoring other ports will not necessarily die because a port dies
		584	"normally").
593		585
594	Otherwise, linked ports get killed with the same reason (second form of	586	Otherwise, linked ports get killed with the same reason (second form of
595	C<mon>, see below).	587	C<mon>, see above).
596		588
597	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	589	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
598	will be reported as reason C<< die => $@ >>.	590	will be reported as reason C<< die => $@ >>.
599		591
600	Transport/communication errors are reported as C<< transport_error =>	592	Transport/communication errors are reported as C<< transport_error =>
601	$message >>.	593	$message >>.
602		594
603	=back
604
605	=head1 NODE MESSAGES
606
607	Nodes understand the following messages sent to them. Many of them take
608	arguments called C<@reply>, which will simply be used to compose a reply
609	message - C<$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	595	=cut
617		596
618	=item lookup => $name, @reply	597	=item $port = spawn $node, $initfunc[, @initdata]
619		598
620	Replies with the port ID of the specified well-known port, or C<undef>.	599	Creates a port on the node C<$node> (which can also be a port ID, in which
		600	case it's the node where that port resides).
621		601
622	=item devnull => ...	602	The port ID of the newly created port is returned immediately, and it is
		603	possible to immediately start sending messages or to monitor the port.
623		604
624	Generic data sink/CPU heat conversion.	605	After the port has been created, the init function is called on the remote
		606	node, in the same context as a C<rcv> callback. This function must be a
		607	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
		608	specify a function in the main program, use C<::name>.
625		609
626	=item relay => $port, @msg	610	If the function doesn't exist, then the node tries to C<require>
		611	the package, then the package above the package and so on (e.g.
		612	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		613	exists or it runs out of package names.
627		614
628	Simply forwards the message to the given port.	615	The init function is then called with the newly-created port as context
		616	object (C<$SELF>) and the C<@initdata> values as arguments.
629		617
630	=item eval => $string[ @reply]	618	A common idiom is to pass a local port, immediately monitor the spawned
		619	port, and in the remote init function, immediately monitor the passed
		620	local port. This two-way monitoring ensures that both ports get cleaned up
		621	when there is a problem.
631		622
632	Evaluates the given string. If C<@reply> is given, then a message of the	623	Example: spawn a chat server port on C<$othernode>.
633	form C<@reply, $@, @evalres> is sent.
634		624
635	Example: crash another node.	625	# this node, executed from within a port context:
		626	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		627	mon $server;
636		628
637	snd $othernode, eval => "exit";	629	# init function on C<$othernode>
		630	sub connect {
		631	my ($srcport) = @_;
638		632
639	=item time => @reply	633	mon $srcport;
640		634
641	Replies the the current node time to C<@reply>.	635	rcv $SELF, sub {
		636	...
		637	};
		638	}
642		639
643	Example: tell the current node to send the current time to C<$myport> in a	640	=cut
644	C<timereply> message.
645		641
646	snd $NODE, time => $myport, timereply => 1, 2;	642	sub _spawn {
647	# => snd $myport, timereply => 1, 2, <time>	643	my $port = shift;
		644	my $init = shift;
		645
		646	local $SELF = "$NODE#$port";
		647	eval {
		648	&{ load_func $init }
		649	};
		650	_self_die if $@;
		651	}
		652
		653	sub spawn(@) {
		654	my ($nodeid, undef) = split /#/, shift, 2;
		655
		656	my $id = "$RUNIQ." . $ID++;
		657
		658	$_[0] =~ /::/
		659	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		660
		661	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
		662
		663	"$nodeid#$id"
		664	}
		665
		666	=item after $timeout, @msg
		667
		668	=item after $timeout, $callback
		669
		670	Either sends the given message, or call the given callback, after the
		671	specified number of seconds.
		672
		673	This is simply a utility function that comes in handy at times - the
		674	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		675	so it may go away in the future.
		676
		677	=cut
		678
		679	sub after($@) {
		680	my ($timeout, @action) = @_;
		681
		682	my $t; $t = AE::timer $timeout, 0, sub {
		683	undef $t;
		684	ref $action[0]
		685	? $action[0]()
		686	: snd @action;
		687	};
		688	}
648		689
649	=back	690	=back
650		691
651	=head1 AnyEvent::MP vs. Distributed Erlang	692	=head1 AnyEvent::MP vs. Distributed Erlang
652		693
…		…
662		703
663	Despite the similarities, there are also some important differences:	704	Despite the similarities, there are also some important differences:
664		705
665	=over 4	706	=over 4
666		707
667	=item * Node references contain the recipe on how to contact them.	708	=item * Node IDs are arbitrary strings in AEMP.
668		709
669	Erlang relies on special naming and DNS to work everywhere in the	710	Erlang relies on special naming and DNS to work everywhere in the same
670	same way. AEMP relies on each node knowing it's own address(es), with	711	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
671	convenience functionality.	712	configuraiton or DNS), but will otherwise discover other odes itself.
672		713
673	This means that AEMP requires a less tightly controlled environment at the	714	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
674	cost of longer node references and a slightly higher management overhead.	715	uses "local ports are like remote ports".
		716
		717	The failure modes for local ports are quite different (runtime errors
		718	only) then for remote ports - when a local port dies, you I<know> it dies,
		719	when a connection to another node dies, you know nothing about the other
		720	port.
		721
		722	Erlang pretends remote ports are as reliable as local ports, even when
		723	they are not.
		724
		725	AEMP encourages a "treat remote ports differently" philosophy, with local
		726	ports being the special case/exception, where transport errors cannot
		727	occur.
675		728
676	=item * Erlang uses processes and a mailbox, AEMP does not queue.	729	=item * Erlang uses processes and a mailbox, AEMP does not queue.
677		730
678	Erlang uses processes that selctively receive messages, and therefore	731	Erlang uses processes that selectively receive messages, and therefore
679	needs a queue. AEMP is event based, queuing messages would serve no useful	732	needs a queue. AEMP is event based, queuing messages would serve no
680	purpose.	733	useful purpose. For the same reason the pattern-matching abilities of
		734	AnyEvent::MP are more limited, as there is little need to be able to
		735	filter messages without dequeing them.
681		736
682	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	737	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
683		738
684	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
685		740
686	Sending messages in Erlang is synchronous and blocks the process. AEMP	741	Sending messages in Erlang is synchronous and blocks the process (and
687	sends are immediate, connection establishment is handled in the	742	so does not need a queue that can overflow). AEMP sends are immediate,
688	background.	743	connection establishment is handled in the background.
689		744
690	=item * Erlang can silently lose messages, AEMP cannot.	745	=item * Erlang suffers from silent message loss, AEMP does not.
691		746
692	Erlang makes few guarantees on messages delivery - messages can get lost	747	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,	748	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).	749	and c, and the other side only receives messages a and c).
695		750
696	AEMP guarantees correct ordering, and the guarantee that there are no	751	AEMP guarantees correct ordering, and the guarantee that after one message
697	holes in the message sequence.	752	is lost, all following ones sent to the same port are lost as well, until
698		753	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	754	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		755
710	=item * Erlang can send messages to the wrong port, AEMP does not.	756	=item * Erlang can send messages to the wrong port, AEMP does not.
711		757
712	In Erlang it is quite possible that a node that restarts reuses a process	758	In Erlang it is quite likely that a node that restarts reuses a process ID
713	ID known to other nodes for a completely different process, causing	759	known to other nodes for a completely different process, causing messages
714	messages destined for that process to end up in an unrelated process.	760	destined for that process to end up in an unrelated process.
715		761
716	AEMP never reuses port IDs, so old messages or old port IDs floating	762	AEMP never reuses port IDs, so old messages or old port IDs floating
717	around in the network will not be sent to an unrelated port.	763	around in the network will not be sent to an unrelated port.
718		764
719	=item * Erlang uses unprotected connections, AEMP uses secure	765	=item * Erlang uses unprotected connections, AEMP uses secure
720	authentication and can use TLS.	766	authentication and can use TLS.
721		767
722	AEMP can use a proven protocol - SSL/TLS - to protect connections and	768	AEMP can use a proven protocol - TLS - to protect connections and
723	securely authenticate nodes.	769	securely authenticate nodes.
724		770
725	=item * The AEMP protocol is optimised for both text-based and binary	771	=item * The AEMP protocol is optimised for both text-based and binary
726	communications.	772	communications.
727		773
728	The AEMP protocol, unlike the Erlang protocol, supports both	774	The AEMP protocol, unlike the Erlang protocol, supports both programming
729	language-independent text-only protocols (good for debugging) and binary,	775	language independent text-only protocols (good for debugging) and binary,
730	language-specific serialisers (e.g. Storable).	776	language-specific serialisers (e.g. Storable). By default, unless TLS is
		777	used, the protocol is actually completely text-based.
731		778
732	It has also been carefully designed to be implementable in other languages	779	It has also been carefully designed to be implementable in other languages
733	with a minimum of work while gracefully degrading fucntionality to make the	780	with a minimum of work while gracefully degrading functionality to make the
734	protocol simple.	781	protocol simple.
735		782
736	=item * AEMP has more flexible monitoring options than Erlang.	783	=item * AEMP has more flexible monitoring options than Erlang.
737		784
738	In Erlang, you can chose to receive I<all> exit signals as messages	785	In Erlang, you can chose to receive I<all> exit signals as messages
…		…
741	Erlang, as one can choose between automatic kill, exit message or callback	788	Erlang, as one can choose between automatic kill, exit message or callback
742	on a per-process basis.	789	on a per-process basis.
743		790
744	=item * Erlang tries to hide remote/local connections, AEMP does not.	791	=item * Erlang tries to hide remote/local connections, AEMP does not.
745		792
746	Monitoring in Erlang is not an indicator of process death/crashes,	793	Monitoring in Erlang is not an indicator of process death/crashes, in the
747	as linking is (except linking is unreliable in Erlang).	794	same way as linking is (except linking is unreliable in Erlang).
748		795
749	In AEMP, you don't "look up" registered port names or send to named ports	796	In AEMP, you don't "look up" registered port names or send to named ports
750	that might or might not be persistent. Instead, you normally spawn a port	797	that might or might not be persistent. Instead, you normally spawn a port
751	on the remote node. The init function monitors the you, and you monitor	798	on the remote node. The init function monitors you, and you monitor the
752	the remote port. Since both monitors are local to the node, they are much	799	remote port. Since both monitors are local to the node, they are much more
753	more reliable.	800	reliable (no need for C<spawn_link>).
754		801
755	This also saves round-trips and avoids sending messages to the wrong port	802	This also saves round-trips and avoids sending messages to the wrong port
756	(hard to do in Erlang).	803	(hard to do in Erlang).
757		804
758	=back	805	=back
759		806
		807	=head1 RATIONALE
		808
		809	=over 4
		810
		811	=item Why strings for port and node IDs, why not objects?
		812
		813	We considered "objects", but found that the actual number of methods
		814	that can be called are quite low. Since port and node IDs travel over
		815	the network frequently, the serialising/deserialising would add lots of
		816	overhead, as well as having to keep a proxy object everywhere.
		817
		818	Strings can easily be printed, easily serialised etc. and need no special
		819	procedures to be "valid".
		820
		821	And as a result, a miniport consists of a single closure stored in a
		822	global hash - it can't become much cheaper.
		823
		824	=item Why favour JSON, why not a real serialising format such as Storable?
		825
		826	In fact, any AnyEvent::MP node will happily accept Storable as framing
		827	format, but currently there is no way to make a node use Storable by
		828	default (although all nodes will accept it).
		829
		830	The default framing protocol is JSON because a) JSON::XS is many times
		831	faster for small messages and b) most importantly, after years of
		832	experience we found that object serialisation is causing more problems
		833	than it solves: Just like function calls, objects simply do not travel
		834	easily over the network, mostly because they will always be a copy, so you
		835	always have to re-think your design.
		836
		837	Keeping your messages simple, concentrating on data structures rather than
		838	objects, will keep your messages clean, tidy and efficient.
		839
		840	=back
		841
760	=head1 SEE ALSO	842	=head1 SEE ALSO
		843
		844	L<AnyEvent::MP::Intro> - a gentle introduction.
		845
		846	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		847
		848	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		849	your applications.
761		850
762	L<AnyEvent>.	851	L<AnyEvent>.
763		852
764	=head1 AUTHOR	853	=head1 AUTHOR
765		854

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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 1.75 by root, Mon Aug 31 13:18:06 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 1.75 by root, Mon Aug 31 13:18:06 2009 UTC