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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
13	$SELF # receiving/own port id in rcv callbacks	12	$SELF # receiving/own port id in rcv callbacks
14		13
15	# initialise the node so it can send/receive messages	14	# initialise the node so it can send/receive messages
16	initialise_node; # -OR-	15	configure;
17	initialise_node "localhost:4040"; # -OR-
18	initialise_node "slave/", "localhost:4040"
19		16
20	# ports are message endpoints	17	# ports are message destinations
21		18
22	# sending messages	19	# sending messages
23	snd $port, type => data...;	20	snd $port, type => data...;
24	snd $port, @msg;	21	snd $port, @msg;
25	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
26		23
27	# creating/using miniports	24	# creating/using ports, the simple way
28	my $miniport = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
29		26
30	# creating/using full ports	27	# creating/using ports, tagged message matching
31	my $port = port;	28	my $port = port;
32	rcv $port, smartmatch => $cb->(@msg);
33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
34	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
35
36	# more, smarter, matches (_any_ is exported by this module)
37	rcv $port, [child_died => $pid] => sub { ...
38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
39		31
40	# create a port on another node	32	# create a port on another node
41	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
42		34
43	# monitoring	35	# monitoring
…		…
45	mon $port, $otherport # kill otherport on abnormal death	37	mon $port, $otherport # kill otherport on abnormal death
46	mon $port, $otherport, @msg # send message on death	38	mon $port, $otherport, @msg # send message on death
47		39
48	=head1 CURRENT STATUS	40	=head1 CURRENT STATUS
49		41
		42	bin/aemp - stable.
50	AnyEvent::MP - stable API, should work	43	AnyEvent::MP - stable API, should work.
51	AnyEvent::MP::Intro - outdated	44	AnyEvent::MP::Intro - explains most concepts.
52	AnyEvent::MP::Kernel - WIP
53	AnyEvent::MP::Transport - mostly stable	45	AnyEvent::MP::Kernel - mostly stable.
		46	AnyEvent::MP::Global - stable API, protocol not yet final.
54		47
55	stay tuned.	48	stay tuned.
56		49
57	=head1 DESCRIPTION	50	=head1 DESCRIPTION
58		51
59	This module (-family) implements a simple message passing framework.	52	This module (-family) implements a simple message passing framework.
60		53
61	Despite its simplicity, you can securely message other processes running	54	Despite its simplicity, you can securely message other processes running
62	on the same or other hosts.	55	on the same or other hosts, and you can supervise entities remotely.
63		56
64	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>
65	manual page.	58	manual page and the examples under F<eg/>.
66
67	At the moment, this module family is severly broken and underdocumented,
68	so do not use. This was uploaded mainly to reserve the CPAN namespace -
69	stay tuned!
70		59
71	=head1 CONCEPTS	60	=head1 CONCEPTS
72		61
73	=over 4	62	=over 4
74		63
75	=item port	64	=item port
76		65
77	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).
78		67
79	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
80	messages. All C<rcv> handlers will receive messages they match, messages	69	some messages. Messages send to ports will not be queued, regardless of
81	will not be queued.	70	anything was listening for them or not.
82		71
83	=item port id - C<noderef#portname>	72	=item port ID - C<nodeid#portname>
84		73
85	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
86	separator, and a port name (a printable string of unspecified format). An	75	separator, and a port name (a printable string of unspecified format).
87	exception is the the node port, whose ID is identical to its node
88	reference.
89		76
90	=item node	77	=item node
91		78
92	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,
93	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
94	create new ports, among other things.	81	ports.
95		82
96	Nodes are either private (single-process only), slaves (connected to a	83	Nodes are either public (have one or more listening ports) or private
97	master node only) or public nodes (connectable from unrelated nodes).	84	(no listening ports). Private nodes cannot talk to other private nodes
		85	currently.
98		86
99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	87	=item node ID - C<[a-za-Z0-9_\-.:]+>
100		88
101	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
102	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
103	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.
104		93
105	This recipe is simply a comma-separated list of C<address:port> pairs (for	94	=item binds - C<ip:port>
106	TCP/IP, other protocols might look different).
107		95
108	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
109	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.
110		100
111	Before using an unresolved node reference in a message you first have to	101	=item seeds - C<host:port>
112	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.
113		115
114	=back	116	=back
115		117
116	=head1 VARIABLES/FUNCTIONS	118	=head1 VARIABLES/FUNCTIONS
117		119
…		…
132	use base "Exporter";	134	use base "Exporter";
133		135
134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	136	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
135		137
136	our @EXPORT = qw(	138	our @EXPORT = qw(
137	NODE $NODE *SELF node_of _any_	139	NODE $NODE *SELF node_of after
138	resolve_node initialise_node	140	configure
139	snd rcv mon kil reg psub spawn	141	snd rcv mon mon_guard kil reg psub spawn
140	port	142	port
141	);	143	);
142		144
143	our $SELF;	145	our $SELF;
144		146
…		…
148	kil $SELF, die => $msg;	150	kil $SELF, die => $msg;
149	}	151	}
150		152
151	=item $thisnode = NODE / $NODE	153	=item $thisnode = NODE / $NODE
152		154
153	The C<NODE> function returns, and the C<$NODE> variable contains	155	The C<NODE> function returns, and the C<$NODE> variable contains, the node
154	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
155	to C<become_public> or C<become_slave>, after which all local port	157	a call to C<configure>.
156	identifiers become invalid.
157		158
158	=item $noderef = node_of $port	159	=item $nodeid = node_of $port
159		160
160	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.
161		162
162	=item initialise_node $noderef, $seednode, $seednode...	163	=item configure $profile, key => value...
163		164
164	=item initialise_node "slave/", $master, $master...	165	=item configure key => value...
165		166
166	Before a node can talk to other nodes on the network it has to initialise	167	Before a node can talk to other nodes on the network (i.e. enter
167	itself - the minimum a node needs to know is it's own name, and optionally	168	"distributed mode") it has to configure itself - the minimum a node needs
168	it should know the noderefs of some other nodes in the network.	169	to know is its own name, and optionally it should know the addresses of
		170	some other nodes in the network to discover other nodes.
169		171
170	This function initialises a node - it must be called exactly once (or	172	This function configures a node - it must be called exactly once (or
171	never) before calling other AnyEvent::MP functions.	173	never) before calling other AnyEvent::MP functions.
172		174
173	All arguments are noderefs, which can be either resolved or unresolved.
174
175	There are two types of networked nodes, public nodes and slave nodes:
176
177	=over 4	175	=over 4
178		176
179	=item public nodes	177	=item step 1, gathering configuration from profiles
180		178
181	For public nodes, C<$noderef> must either be a (possibly unresolved)	179	The function first looks up a profile in the aemp configuration (see the
182	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
183	which case the noderef will be guessed.	181	named C<profile> parameter or can simply be the first parameter). If it is
		182	missing, then the nodename (F<uname -n>) will be used as profile name.
184		183
185	Afterwards, the node will bind itself on all endpoints and try to connect	184	The profile data is then gathered as follows:
186	to all additional C<$seednodes> that are specified. Seednodes are optional
187	and can be used to quickly bootstrap the node into an existing network.
188		185
189	=item slave nodes	186	First, all remaining key => value pairs (all of which are conveniently
		187	undocumented at the moment) will be interpreted as configuration
		188	data. Then they will be overwritten by any values specified in the global
		189	default configuration (see the F<aemp> utility), then the chain of
		190	profiles chosen by the profile name (and any C<parent> attributes).
190		191
191	When the C<$noderef> is the special string C<slave/>, then the node will	192	That means that the values specified in the profile have highest priority
192	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,
193	route most of their traffic to the master node that they attach to.	194	and can only be used to specify defaults.
194		195
195	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
196	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
197	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.
198		217
199	=back	218	=back
200		219
201	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.
202	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.
203	server.
204		222
205	Example: become a public node listening on the default node.	223	configure
206		224
207	initialise_node;	225	Example: become an anonymous node. This form is often used for commandline
		226	clients.
208		227
209	Example: become a public node, and try to contact some well-known master	228	configure nodeid => "anon/";
210	servers to become part of the network.
211		229
212	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).
213		233
214	Example: become a public node listening on port C<4041>.	234	# use the aemp commandline utility
		235	# aemp profile seed nodeid anon/ binds '*:4040'
215		236
216	initialise_node 4041;	237	# then use it
		238	configure profile => "seed";
217		239
218	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
219		242
220	initialise_node "locahost:4044";	243	# or provide a nicer-to-remember nodeid
221		244	# aemp run profile seed nodeid "$(hostname)"
222	Example: become a slave node to any of the specified master servers.
223
224	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
225
226	=item $cv = resolve_node $noderef
227
228	Takes an unresolved node reference that may contain hostnames and
229	abbreviated IDs, resolves all of them and returns a resolved node
230	reference.
231
232	In addition to C<address:port> pairs allowed in resolved noderefs, the
233	following forms are supported:
234
235	=over 4
236
237	=item the empty string
238
239	An empty-string component gets resolved as if the default port (4040) was
240	specified.
241
242	=item naked port numbers (e.g. C<1234>)
243
244	These are resolved by prepending the local nodename and a colon, to be
245	further resolved.
246
247	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
248
249	These are resolved by using AnyEvent::DNS to resolve them, optionally
250	looking up SRV records for the C<aemp=4040> port, if no port was
251	specified.
252
253	=back
254		245
255	=item $SELF	246	=item $SELF
256		247
257	Contains the current port id while executing C<rcv> callbacks or C<psub>	248	Contains the current port id while executing C<rcv> callbacks or C<psub>
258	blocks.	249	blocks.
259		250
260	=item SELF, %SELF, @SELF...	251	=item *SELF, SELF, %SELF, @SELF...
261		252
262	Due to some quirks in how perl exports variables, it is impossible to	253	Due to some quirks in how perl exports variables, it is impossible to
263	just export C<$SELF>, all the symbols called C<SELF> are exported by this	254	just export C<$SELF>, all the symbols named C<SELF> are exported by this
264	module, but only C<$SELF> is currently used.	255	module, but only C<$SELF> is currently used.
265		256
266	=item snd $port, type => @data	257	=item snd $port, type => @data
267		258
268	=item snd $port, @msg	259	=item snd $port, @msg
269		260
270	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
271	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.
272	stringifies a sa port ID (such as a port object :).
273		263
274	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
275	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
276	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.
277		268
278	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
279	function: modifying any argument is not allowed and can cause many	270	function: modifying any argument (or values referenced by them) is
280	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.
281		275
282	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
283	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
284	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
285	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
286	node, anything can be passed.	280	node, anything can be passed. Best rely only on the common denominator of
		281	these.
287		282
288	=item $local_port = port	283	=item $local_port = port
289		284
290	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
291	matching port ("full port") or a single-callback port ("miniport"),	286	no callbacks set and will throw an error when it receives messages.
292	depending on how C<rcv> callbacks are bound to the object.
293		287
294	=item $port = port { my @msg = @_; $finished }	288	=item $local_port = port { my @msg = @_ }
295		289
296	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
297	matching behind it, and returns its ID. Semantically the same as creating
298	a port and calling C<rcv $port, $callback> on it.	291	creating a port and calling C<rcv $port, $callback> on it.
299		292
300	The block will be called for every message received on the port. When the	293	The block will be called for every message received on the port, with the
301	callback returns a true value its job is considered "done" and the port	294	global variable C<$SELF> set to the port ID. Runtime errors will cause the
302	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.
303		297
304	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:
305	be passed to the callback.
306		299
307	If you need the local port id in the callback, this works nicely:	300	my $port = port {
308		301	my @msg = @_;
309	my $port; $port = port {	302	...
310	snd $otherport, reply => $port;	303	kil $SELF;
311	};	304	};
312		305
313	=cut	306	=cut
314		307
315	sub rcv($@);	308	sub rcv($@);
		309
		310	sub _kilme {
		311	die "received message on port without callback";
		312	}
316		313
317	sub port(;&) {	314	sub port(;&) {
318	my $id = "$UNIQ." . $ID++;	315	my $id = "$UNIQ." . $ID++;
319	my $port = "$NODE#$id";	316	my $port = "$NODE#$id";
320		317
321	if (@_) {	318	rcv $port, shift \|\| \&_kilme;
322	rcv $port, shift;
323	} else {
324	$PORT{$id} = sub { }; # nop
325	}
326		319
327	$port	320	$port
328	}	321	}
329		322
330	=item reg $port, $name
331
332	=item reg $name
333
334	Registers the given port (or C<$SELF><<< if missing) under the name
335	C<$name>. If the name already exists it is replaced.
336
337	A port can only be registered under one well known name.
338
339	A port automatically becomes unregistered when it is killed.
340
341	=cut
342
343	sub reg(@) {
344	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
345
346	$REG{$_[0]} = $port;
347	}
348
349	=item rcv $port, $callback->(@msg)	323	=item rcv $local_port, $callback->(@msg)
350		324
351	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
352	one if required).	326	remove the default callback: use C<sub { }> to disable it, or better
353		327	C<kil> the port when it is no longer needed.
354	=item rcv $port, tagstring => $callback->(@msg), ...
355
356	=item rcv $port, $smartmatch => $callback->(@msg), ...
357
358	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
359
360	Register callbacks to be called on matching messages on the given full
361	port (after converting it to one if required) and return the port.
362
363	The callback has to return a true value when its work is done, after
364	which is will be removed, or a false value in which case it will stay
365	registered.
366		328
367	The global C<$SELF> (exported by this module) contains C<$port> while	329	The global C<$SELF> (exported by this module) contains C<$port> while
368	executing the callback.	330	executing the callback. Runtime errors during callback execution will
		331	result in the port being C<kil>ed.
369		332
370	Runtime errors during callback execution will result in the port being	333	The default callback received all messages not matched by a more specific
371	C<kil>ed.	334	C<tag> match.
372		335
373	If the match is an array reference, then it will be matched against the	336	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
374	first elements of the message, otherwise only the first element is being
375	matched.
376		337
377	Any element in the match that is specified as C<_any_> (a function	338	Register (or replace) callbacks to be called on messages starting with the
378	exported by this module) matches any single element of the message.	339	given tag on the given port (and return the port), or unregister it (when
		340	C<$callback> is C<$undef> or missing). There can only be one callback
		341	registered for each tag.
379		342
380	While not required, it is highly recommended that the first matching	343	The original message will be passed to the callback, after the first
381	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
382	also the most efficient match (by far).	345	environment as the default callback (see above).
383		346
384	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.
385		348
386	my $port = rcv port,	349	my $port = rcv port,
387	msg1 => sub { ...; 0 },	350	msg1 => sub { ... },
388	msg2 => sub { ...; 0 },	351	msg2 => sub { ... },
389	;	352	;
390		353
391	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
392	in one go:	355	in one go:
393		356
394	snd $otherport, reply =>	357	snd $otherport, reply =>
395	rcv port,	358	rcv port,
396	msg1 => sub { ...; 0 },	359	msg1 => sub { ... },
397	...	360	...
398	;	361	;
399		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, $otherport;
		370	};
		371
400	=cut	372	=cut
401		373
402	sub rcv($@) {	374	sub rcv($@) {
403	my $port = shift;	375	my $port = shift;
404	my ($noderef, $portid) = split /#/, $port, 2;	376	my ($nodeid, $portid) = split /#/, $port, 2;
405		377
406	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}	378	$NODE{$nodeid} == $NODE{""}
407	or Carp::croak "$port: rcv can only be called on local ports, caught";	379	or Carp::croak "$port: rcv can only be called on local ports, caught";
408		380
409	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 {
410	my $cb = shift;	389	my $cb = shift;
411	delete $PORT_DATA{$portid};
412	$PORT{$portid} = sub {	390	$PORT{$portid} = sub {
413	local $SELF = $port;	391	local $SELF = $port;
414	eval {	392	eval { &$cb }; _self_die if $@;
415	&$cb	393	};
416	and kil $port;
417	};	394	}
418	_self_die if $@;	395	} elsif (defined $_[0]) {
419	};
420	} else {
421	my $self = $PORT_DATA{$portid} \|\|= do {	396	my $self = $PORT_DATA{$portid} \|\|= do {
422	my $self = bless {	397	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
423	id => $port,
424	}, "AnyEvent::MP::Port";
425		398
426	$PORT{$portid} = sub {	399	$PORT{$portid} = sub {
427	local $SELF = $port;	400	local $SELF = $port;
428		401
429	eval {
430	for (@{ $self->{rc0}{$_[0]} }) {	402	if (my $cb = $self->[1]{$_[0]}) {
431	$_ && &{$_->[0]}	403	shift;
432	&& undef $_;	404	eval { &$cb }; _self_die if $@;
433	}	405	} else {
434
435	for (@{ $self->{rcv}{$_[0]} }) {
436	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
437	&& &{$_->[0]}	406	&{ $self->[0] };
438	&& undef $_;
439	}
440
441	for (@{ $self->{any} }) {
442	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
443	&& &{$_->[0]}
444	&& undef $_;
445	}	407	}
446	};	408	};
447	_self_die if $@;	409
		410	$self
448	};	411	};
449		412
450	$self
451	};
452
453	"AnyEvent::MP::Port" eq ref $self	413	"AnyEvent::MP::Port" eq ref $self
454	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
455		415
456	while (@_) {
457	my ($match, $cb) = splice @_, 0, 2;	416	my ($tag, $cb) = splice @_, 0, 2;
458		417
459	if (!ref $match) {	418	if (defined $cb) {
460	push @{ $self->{rc0}{$match} }, [$cb];	419	$self->[1]{$tag} = $cb;
461	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
462	my ($type, @match) = @$match;
463	@match
464	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
465	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
466	} else {	420	} else {
467	push @{ $self->{any} }, [$cb, $match];	421	delete $self->[1]{$tag};
468	}	422	}
469	}	423	}
470	}	424	}
471		425
472	$port	426	$port
…		…
508	$res	462	$res
509	}	463	}
510	}	464	}
511	}	465	}
512		466
513	=item $guard = mon $port, $cb->(@reason)	467	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
514		468
515	=item $guard = mon $port, $rcvport	469	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
516		470
517	=item $guard = mon $port	471	=item $guard = mon $port # kill $SELF when $port dies
518		472
519	=item $guard = mon $port, $rcvport, @msg	473	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
520		474
521	Monitor the given port and do something when the port is killed or	475	Monitor the given port and do something when the port is killed or
522	messages to it were lost, and optionally return a guard that can be used	476	messages to it were lost, and optionally return a guard that can be used
523	to stop monitoring again.	477	to stop monitoring again.
524		478
525	C<mon> effectively guarantees that, in the absence of hardware failures,	479	C<mon> effectively guarantees that, in the absence of hardware failures,
526	that after starting the monitor, either all messages sent to the port	480	after starting the monitor, either all messages sent to the port will
527	will arrive, or the monitoring action will be invoked after possible	481	arrive, or the monitoring action will be invoked after possible message
528	message loss has been detected. No messages will be lost "in between"	482	loss has been detected. No messages will be lost "in between" (after
529	(after the first lost message no further messages will be received by the	483	the first lost message no further messages will be received by the
530	port). After the monitoring action was invoked, further messages might get	484	port). After the monitoring action was invoked, further messages might get
531	delivered again.	485	delivered again.
		486
		487	Note that monitoring-actions are one-shot: once messages are lost (and a
		488	monitoring alert was raised), they are removed and will not trigger again.
532		489
533	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
534	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
535	"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
536	C<eval> if unsure.	493	C<eval> if unsure.
537		494
538	In the second form (another port given), the other port (C<$rcvport>)	495	In the second form (another port given), the other port (C<$rcvport>)
539	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	496	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
540	"normal" kils nothing happens, while under all other conditions, the other	497	"normal" kils nothing happens, while under all other conditions, the other
541	port is killed with the same reason.	498	port is killed with the same reason.
542		499
543	The third form (kill self) is the same as the second form, except that	500	The third form (kill self) is the same as the second form, except that
544	C<$rvport> defaults to C<$SELF>.	501	C<$rvport> defaults to C<$SELF>.
…		…
547	C<snd>.	504	C<snd>.
548		505
549	As a rule of thumb, monitoring requests should always monitor a port from	506	As a rule of thumb, monitoring requests should always monitor a port from
550	a local port (or callback). The reason is that kill messages might get	507	a local port (or callback). The reason is that kill messages might get
551	lost, just like any other message. Another less obvious reason is that	508	lost, just like any other message. Another less obvious reason is that
552	even monitoring requests can get lost (for exmaple, when the connection	509	even monitoring requests can get lost (for example, when the connection
553	to the other node goes down permanently). When monitoring a port locally	510	to the other node goes down permanently). When monitoring a port locally
554	these problems do not exist.	511	these problems do not exist.
555		512
556	Example: call a given callback when C<$port> is killed.	513	Example: call a given callback when C<$port> is killed.
557		514
…		…
566	mon $port, $self => "restart";	523	mon $port, $self => "restart";
567		524
568	=cut	525	=cut
569		526
570	sub mon {	527	sub mon {
571	my ($noderef, $port) = split /#/, shift, 2;	528	my ($nodeid, $port) = split /#/, shift, 2;
572		529
573	my $node = $NODE{$noderef} \|\| add_node $noderef;	530	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
574		531
575	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	532	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
576		533
577	unless (ref $cb) {	534	unless (ref $cb) {
578	if (@_) {	535	if (@_) {
…		…
598	is killed, the references will be freed.	555	is killed, the references will be freed.
599		556
600	Optionally returns a guard that will stop the monitoring.	557	Optionally returns a guard that will stop the monitoring.
601		558
602	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
603	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>):
604		561
605	$port->rcv (start => sub {	562	$port->rcv (start => sub {
606	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {	563	my $timer; $timer = mon_guard $port, AE::timer 1, 1, psub {
607	undef $timer if 0.9 < rand;	564	undef $timer if 0.9 < rand;
608	});	565	});
609	});	566	});
610		567
611	=cut	568	=cut
…		…
620		577
621	=item kil $port[, @reason]	578	=item kil $port[, @reason]
622		579
623	Kill the specified port with the given C<@reason>.	580	Kill the specified port with the given C<@reason>.
624		581
625	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
626	ports will not be kileld, or even notified).	583	monitoring other ports will not necessarily die because a port dies
		584	"normally").
627		585
628	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
629	C<mon>, see below).	587	C<mon>, see above).
630		588
631	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
632	will be reported as reason C<< die => $@ >>.	590	will be reported as reason C<< die => $@ >>.
633		591
634	Transport/communication errors are reported as C<< transport_error =>	592	Transport/communication errors are reported as C<< transport_error =>
…		…
639	=item $port = spawn $node, $initfunc[, @initdata]	597	=item $port = spawn $node, $initfunc[, @initdata]
640		598
641	Creates a port on the node C<$node> (which can also be a port ID, in which	599	Creates a port on the node C<$node> (which can also be a port ID, in which
642	case it's the node where that port resides).	600	case it's the node where that port resides).
643		601
644	The port ID of the newly created port is return immediately, and it is	602	The port ID of the newly created port is returned immediately, and it is
645	permissible to immediately start sending messages or monitor the port.	603	possible to immediately start sending messages or to monitor the port.
646		604
647	After the port has been created, the init function is	605	After the port has been created, the init function is called on the remote
648	called. This function must be a fully-qualified function name	606	node, in the same context as a C<rcv> callback. This function must be a
649	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main	607	fully-qualified function name (e.g. C<MyApp::Chat::Server::init>). To
650	program, use C<::name>.	608	specify a function in the main program, use C<::name>.
651		609
652	If the function doesn't exist, then the node tries to C<require>	610	If the function doesn't exist, then the node tries to C<require>
653	the package, then the package above the package and so on (e.g.	611	the package, then the package above the package and so on (e.g.
654	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	612	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
655	exists or it runs out of package names.	613	exists or it runs out of package names.
656		614
657	The init function is then called with the newly-created port as context	615	The init function is then called with the newly-created port as context
658	object (C<$SELF>) and the C<@initdata> values as arguments.	616	object (C<$SELF>) and the C<@initdata> values as arguments.
659		617
660	A common idiom is to pass your own port, monitor the spawned port, and	618	A common idiom is to pass a local port, immediately monitor the spawned
661	in the init function, monitor the original port. This two-way monitoring	619	port, and in the remote init function, immediately monitor the passed
662	ensures that both ports get cleaned up when there is a problem.	620	local port. This two-way monitoring ensures that both ports get cleaned up
		621	when there is a problem.
663		622
664	Example: spawn a chat server port on C<$othernode>.	623	Example: spawn a chat server port on C<$othernode>.
665		624
666	# this node, executed from within a port context:	625	# this node, executed from within a port context:
667	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	626	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
…		…
690	};	649	};
691	_self_die if $@;	650	_self_die if $@;
692	}	651	}
693		652
694	sub spawn(@) {	653	sub spawn(@) {
695	my ($noderef, undef) = split /#/, shift, 2;	654	my ($nodeid, undef) = split /#/, shift, 2;
696		655
697	my $id = "$RUNIQ." . $ID++;	656	my $id = "$RUNIQ." . $ID++;
698		657
699	$_[0] =~ /::/	658	$_[0] =~ /::/
700	or Carp::croak "spawn init function must be a fully-qualified name, caught";	659	or Carp::croak "spawn init function must be a fully-qualified name, caught";
701		660
702	($NODE{$noderef} \|\| add_node $noderef)	661	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
703	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
704		662
705	"$noderef#$id"	663	"$nodeid#$id"
706	}	664	}
707		665
708	=back	666	=item after $timeout, @msg
709		667
710	=head1 NODE MESSAGES	668	=item after $timeout, $callback
711		669
712	Nodes understand the following messages sent to them. Many of them take	670	Either sends the given message, or call the given callback, after the
713	arguments called C<@reply>, which will simply be used to compose a reply	671	specified number of seconds.
714	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
715	the remaining arguments are simply the message data.
716		672
717	While other messages exist, they are not public and subject to change.	673	This is simply a utility function that comes in handy at times - the
		674	AnyEvent::MP author is not convinced of the wisdom of having it, though,
		675	so it may go away in the future.
718		676
719	=over 4
720
721	=cut	677	=cut
722		678
723	=item lookup => $name, @reply	679	sub after($@) {
		680	my ($timeout, @action) = @_;
724		681
725	Replies with the port ID of the specified well-known port, or C<undef>.	682	my $t; $t = AE::timer $timeout, 0, sub {
726		683	undef $t;
727	=item devnull => ...	684	ref $action[0]
728		685	? $action[0]()
729	Generic data sink/CPU heat conversion.	686	: snd @action;
730		687	};
731	=item relay => $port, @msg	688	}
732
733	Simply forwards the message to the given port.
734
735	=item eval => $string[ @reply]
736
737	Evaluates the given string. If C<@reply> is given, then a message of the
738	form C<@reply, $@, @evalres> is sent.
739
740	Example: crash another node.
741
742	snd $othernode, eval => "exit";
743
744	=item time => @reply
745
746	Replies the the current node time to C<@reply>.
747
748	Example: tell the current node to send the current time to C<$myport> in a
749	C<timereply> message.
750
751	snd $NODE, time => $myport, timereply => 1, 2;
752	# => snd $myport, timereply => 1, 2, <time>
753		689
754	=back	690	=back
755		691
756	=head1 AnyEvent::MP vs. Distributed Erlang	692	=head1 AnyEvent::MP vs. Distributed Erlang
757		693
…		…
767		703
768	Despite the similarities, there are also some important differences:	704	Despite the similarities, there are also some important differences:
769		705
770	=over 4	706	=over 4
771		707
772	=item * Node references contain the recipe on how to contact them.	708	=item * Node IDs are arbitrary strings in AEMP.
773		709
774	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
775	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
776	convenience functionality.	712	configuration or DNS), but will otherwise discover other odes itself.
777		713
778	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
779	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.
780		728
781	=item * Erlang uses processes and a mailbox, AEMP does not queue.	729	=item * Erlang uses processes and a mailbox, AEMP does not queue.
782		730
783	Erlang uses processes that selctively receive messages, and therefore	731	Erlang uses processes that selectively receive messages, and therefore
784	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
785	purpose.	733	useful purpose. For the same reason the pattern-matching abilities of
		734	AnyEvent::MP are more limited, as there is little need to be able to
		735	filter messages without dequeuing them.
786		736
787	(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).
788		738
789	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	739	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
790		740
791	Sending messages in Erlang is synchronous and blocks the process. AEMP	741	Sending messages in Erlang is synchronous and blocks the process (and
792	sends are immediate, connection establishment is handled in the	742	so does not need a queue that can overflow). AEMP sends are immediate,
793	background.	743	connection establishment is handled in the background.
794		744
795	=item * Erlang can silently lose messages, AEMP cannot.	745	=item * Erlang suffers from silent message loss, AEMP does not.
796		746
797	Erlang makes few guarantees on messages delivery - messages can get lost	747	Erlang makes few guarantees on messages delivery - messages can get lost
798	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,
799	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).
800		750
801	AEMP guarantees correct ordering, and the guarantee that there are no	751	AEMP guarantees correct ordering, and the guarantee that after one message
802	holes in the message sequence.	752	is lost, all following ones sent to the same port are lost as well, until
803		753	monitoring raises an error, so there are no silent "holes" in the message
804	=item * In Erlang, processes can be declared dead and later be found to be	754	sequence.
805	alive.
806
807	In Erlang it can happen that a monitored process is declared dead and
808	linked processes get killed, but later it turns out that the process is
809	still alive - and can receive messages.
810
811	In AEMP, when port monitoring detects a port as dead, then that port will
812	eventually be killed - it cannot happen that a node detects a port as dead
813	and then later sends messages to it, finding it is still alive.
814		755
815	=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.
816		757
817	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
818	ID known to other nodes for a completely different process, causing	759	known to other nodes for a completely different process, causing messages
819	messages destined for that process to end up in an unrelated process.	760	destined for that process to end up in an unrelated process.
820		761
821	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
822	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.
823		764
824	=item * Erlang uses unprotected connections, AEMP uses secure	765	=item * Erlang uses unprotected connections, AEMP uses secure
825	authentication and can use TLS.	766	authentication and can use TLS.
826		767
827	AEMP can use a proven protocol - SSL/TLS - to protect connections and	768	AEMP can use a proven protocol - TLS - to protect connections and
828	securely authenticate nodes.	769	securely authenticate nodes.
829		770
830	=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
831	communications.	772	communications.
832		773
833	The AEMP protocol, unlike the Erlang protocol, supports both	774	The AEMP protocol, unlike the Erlang protocol, supports both programming
834	language-independent text-only protocols (good for debugging) and binary,	775	language independent text-only protocols (good for debugging) and binary,
835	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.
836		778
837	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
838	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
839	protocol simple.	781	protocol simple.
840		782
841	=item * AEMP has more flexible monitoring options than Erlang.	783	=item * AEMP has more flexible monitoring options than Erlang.
842		784
843	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
…		…
846	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
847	on a per-process basis.	789	on a per-process basis.
848		790
849	=item * Erlang tries to hide remote/local connections, AEMP does not.	791	=item * Erlang tries to hide remote/local connections, AEMP does not.
850		792
851	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
852	as linking is (except linking is unreliable in Erlang).	794	same way as linking is (except linking is unreliable in Erlang).
853		795
854	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
855	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
856	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
857	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
858	more reliable.	800	reliable (no need for C<spawn_link>).
859		801
860	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
861	(hard to do in Erlang).	803	(hard to do in Erlang).
862		804
863	=back	805	=back
864		806
865	=head1 RATIONALE	807	=head1 RATIONALE
866		808
867	=over 4	809	=over 4
868		810
869	=item Why strings for ports and noderefs, why not objects?	811	=item Why strings for port and node IDs, why not objects?
870		812
871	We considered "objects", but found that the actual number of methods	813	We considered "objects", but found that the actual number of methods
872	thatc an be called are very low. Since port IDs and noderefs travel over	814	that can be called are quite low. Since port and node IDs travel over
873	the network frequently, the serialising/deserialising would add lots of	815	the network frequently, the serialising/deserialising would add lots of
874	overhead, as well as having to keep a proxy object.	816	overhead, as well as having to keep a proxy object everywhere.
875		817
876	Strings can easily be printed, easily serialised etc. and need no special	818	Strings can easily be printed, easily serialised etc. and need no special
877	procedures to be "valid".	819	procedures to be "valid".
878		820
879	And a a miniport consists of a single closure stored in a global hash - it	821	And as a result, a miniport consists of a single closure stored in a
880	can't become much cheaper.	822	global hash - it can't become much cheaper.
881		823
882	=item Why favour JSON, why not real serialising format such as Storable?	824	=item Why favour JSON, why not a real serialising format such as Storable?
883		825
884	In fact, any AnyEvent::MP node will happily accept Storable as framing	826	In fact, any AnyEvent::MP node will happily accept Storable as framing
885	format, but currently there is no way to make a node use Storable by	827	format, but currently there is no way to make a node use Storable by
886	default.	828	default (although all nodes will accept it).
887		829
888	The default framing protocol is JSON because a) JSON::XS is many times	830	The default framing protocol is JSON because a) JSON::XS is many times
889	faster for small messages and b) most importantly, after years of	831	faster for small messages and b) most importantly, after years of
890	experience we found that object serialisation is causing more problems	832	experience we found that object serialisation is causing more problems
891	than it gains: Just like function calls, objects simply do not travel	833	than it solves: Just like function calls, objects simply do not travel
892	easily over the network, mostly because they will always be a copy, so you	834	easily over the network, mostly because they will always be a copy, so you
893	always have to re-think your design.	835	always have to re-think your design.
894		836
895	Keeping your messages simple, concentrating on data structures rather than	837	Keeping your messages simple, concentrating on data structures rather than
896	objects, will keep your messages clean, tidy and efficient.	838	objects, will keep your messages clean, tidy and efficient.
897		839
898	=back	840	=back
899		841
900	=head1 SEE ALSO	842	=head1 SEE ALSO
901		843
		844	L<AnyEvent::MP::Intro> - a gentle introduction.
		845
		846	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
		847
		848	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
		849	your applications.
		850
902	L<AnyEvent>.	851	L<AnyEvent>.
903		852
904	=head1 AUTHOR	853	=head1 AUTHOR
905		854
906	Marc Lehmann <schmorp@schmorp.de>	855	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs. Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.48 by root, Thu Aug 13 02:59:42 2009 UTC vs.
Revision 1.78 by root, Thu Sep 3 20:16:36 2009 UTC