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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.5 by root, Sat Aug 1 07:44:02 2009 UTC vs.
Revision 1.34 by root, Wed Aug 5 23:50:46 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	NODE # returns this node identifier
10	$NODE # contains this node identifier	9	$NODE # contains this node's noderef
		10	NODE # returns this node's noderef
		11	NODE $port # returns the noderef of the port
11		12
12	snd $port, type => data...;	13	snd $port, type => data...;
		14
		15	$SELF # receiving/own port id in rcv callbacks
13		16
14	rcv $port, smartmatch => $cb->($port, @msg);	17	rcv $port, smartmatch => $cb->($port, @msg);
15		18
16	# examples:	19	# examples:
17	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };
…		…
27	This module (-family) implements a simple message passing framework.	30	This module (-family) implements a simple message passing framework.
28		31
29	Despite its simplicity, you can securely message other processes running	32	Despite its simplicity, you can securely message other processes running
30	on the same or other hosts.	33	on the same or other hosts.
31		34
		35	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		36	manual page.
		37
		38	At the moment, this module family is severly broken and underdocumented,
		39	so do not use. This was uploaded mainly to reserve the CPAN namespace -
		40	stay tuned! The basic API should be finished, however.
		41
32	=head1 CONCEPTS	42	=head1 CONCEPTS
33		43
34	=over 4	44	=over 4
35		45
36	=item port	46	=item port
37		47
38	A port is something you can send messages to with the C<snd> function, and	48	A port is something you can send messages to (with the C<snd> function).
39	you can register C<rcv> handlers with. All C<rcv> handlers will receive	49
40	messages they match, messages will not be queued.	50	Some ports allow you to register C<rcv> handlers that can match specific
		51	messages. All C<rcv> handlers will receive messages they match, messages
		52	will not be queued.
41		53
42	=item port id - C<noderef#portname>	54	=item port id - C<noderef#portname>
43		55
44	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	56	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as
45	by a port name (a printable string of unspecified format).	57	separator, and a port name (a printable string of unspecified format). An
		58	exception is the the node port, whose ID is identical to its node
		59	reference.
46		60
47	=item node	61	=item node
48		62
49	A node is a single process containing at least one port - the node	63	A node is a single process containing at least one port - the node
50	port. You can send messages to node ports to let them create new ports,	64	port. You can send messages to node ports to find existing ports or to
51	among other things.	65	create new ports, among other things.
52		66
53	Initially, nodes are either private (single-process only) or hidden	67	Nodes are either private (single-process only), slaves (connected to a
54	(connected to a master node only). Only when they epxlicitly "become	68	master node only) or public nodes (connectable from unrelated nodes).
55	public" can you send them messages from unrelated other nodes.
56		69
57	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	70	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
58		71
59	A noderef is a string that either uniquely identifies a given node (for	72	A node reference is a string that either simply identifies the node (for
60	private and hidden nodes), or contains a recipe on how to reach a given	73	private and slave nodes), or contains a recipe on how to reach a given
61	node (for public nodes).	74	node (for public nodes).
62		75
		76	This recipe is simply a comma-separated list of C<address:port> pairs (for
		77	TCP/IP, other protocols might look different).
		78
		79	Node references come in two flavours: resolved (containing only numerical
		80	addresses) or unresolved (where hostnames are used instead of addresses).
		81
		82	Before using an unresolved node reference in a message you first have to
		83	resolve it.
		84
63	=back	85	=back
64		86
65	=head1 VARIABLES/FUNCTIONS	87	=head1 VARIABLES/FUNCTIONS
66		88
67	=over 4	89	=over 4
68		90
69	=cut	91	=cut
70		92
71	package AnyEvent::MP;	93	package AnyEvent::MP;
72		94
73	use AnyEvent::MP::Util ();
74	use AnyEvent::MP::Node;	95	use AnyEvent::MP::Base;
75	use AnyEvent::MP::Transport;
76		96
77	use utf8;
78	use common::sense;	97	use common::sense;
79		98
80	use Carp ();	99	use Carp ();
81		100
82	use AE ();	101	use AE ();
83		102
84	use base "Exporter";	103	use base "Exporter";
85		104
86	our $VERSION = '0.0';	105	our $VERSION = '0.1';
87	our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_);	106	our @EXPORT = qw(
		107	NODE $NODE *SELF node_of _any_
		108	resolve_node initialise_node
		109	snd rcv mon kil reg psub
		110	port
		111	);
88		112
89	our $DEFAULT_SECRET;	113	our $SELF;
90	our $DEFAULT_PORT = "4040";
91		114
92	our $CONNECT_INTERVAL = 5; # new connect every 5s, at least	115	sub _self_die() {
93	our $CONNECT_TIMEOUT = 30; # includes handshake	116	my $msg = $@;
94		117	$msg =~ s/\n+$// unless ref $msg;
95	sub default_secret {	118	kil $SELF, die => $msg;
96	unless (defined $DEFAULT_SECRET) {
97	if (open my $fh, "<$ENV{HOME}/.aemp-secret") {
98	sysread $fh, $DEFAULT_SECRET, -s $fh;
99	} else {
100	$DEFAULT_SECRET = AnyEvent::MP::Util::nonce 32;
101	}
102	}
103
104	$DEFAULT_SECRET
105	}	119	}
106		120
107	=item NODE / $NODE	121	=item $thisnode = NODE / $NODE
108		122
109	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	123	The C<NODE> function returns, and the C<$NODE> variable contains
110	the local node. The value is initialised by a call to C<become_public> or	124	the noderef of the local node. The value is initialised by a call
111	C<become_slave>, after which all local port identifiers become invalid.	125	to C<become_public> or C<become_slave>, after which all local port
		126	identifiers become invalid.
112		127
113	=cut	128	=item $noderef = node_of $port
114		129
115	our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie	130	Extracts and returns the noderef from a portid or a noderef.
116	our $PUBLIC = 0;
117	our $NODE;
118	our $PORT;
119		131
120	our %NODE; # node id to transport mapping, or "undef", for local node	132	=item initialise_node $noderef, $seednode, $seednode...
121	our %PORT; # local ports
122	our %LISTENER; # local transports
123		133
124	sub NODE() { $NODE }	134	=item initialise_node "slave/", $master, $master...
125		135
126	{	136	Before a node can talk to other nodes on the network it has to initialise
127	use POSIX ();	137	itself - the minimum a node needs to know is it's own name, and optionally
128	my $nodename = (POSIX::uname)[1];	138	it should know the noderefs of some other nodes in the network.
129	$NODE = "$$\@$nodename";
130	}
131		139
132	sub _ANY_() { 1 }	140	This function initialises a node - it must be called exactly once (or
133	sub _any_() { \&_ANY_ }	141	never) before calling other AnyEvent::MP functions.
134		142
135	sub add_node {	143	All arguments are noderefs, which can be either resolved or unresolved.
136	my ($noderef) = @_;
137		144
138	return $NODE{$noderef}	145	There are two types of networked nodes, public nodes and slave nodes:
139	if exists $NODE{$noderef};
140		146
141	for (split /,/, $noderef) {	147	=over 4
142	return $NODE{$noderef} = $NODE{$_}
143	if exists $NODE{$_};
144	}
145		148
146	# for indirect sends, use a different class	149	=item public nodes
147	my $node = new AnyEvent::MP::Node::Direct $noderef;
148		150
149	$NODE{$_} = $node	151	For public nodes, C<$noderef> must either be a (possibly unresolved)
150	for $noderef, split /,/, $noderef;	152	noderef, in which case it will be resolved, or C<undef> (or missing), in
		153	which case the noderef will be guessed.
151		154
152	$node	155	Afterwards, the node will bind itself on all endpoints and try to connect
153	}	156	to all additional C<$seednodes> that are specified. Seednodes are optional
		157	and can be used to quickly bootstrap the node into an existing network.
154		158
		159	=item slave nodes
		160
		161	When the C<$noderef> is the special string C<slave/>, then the node will
		162	become a slave node. Slave nodes cannot be contacted from outside and will
		163	route most of their traffic to the master node that they attach to.
		164
		165	At least one additional noderef is required: The node will try to connect
		166	to all of them and will become a slave attached to the first node it can
		167	successfully connect to.
		168
		169	=back
		170
		171	This function will block until all nodes have been resolved and, for slave
		172	nodes, until it has successfully established a connection to a master
		173	server.
		174
		175	Example: become a public node listening on the default node.
		176
		177	initialise_node;
		178
		179	Example: become a public node, and try to contact some well-known master
		180	servers to become part of the network.
		181
		182	initialise_node undef, "master1", "master2";
		183
		184	Example: become a public node listening on port C<4041>.
		185
		186	initialise_node 4041;
		187
		188	Example: become a public node, only visible on localhost port 4044.
		189
		190	initialise_node "locahost:4044";
		191
		192	Example: become a slave node to any of the specified master servers.
		193
		194	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		195
		196	=item $cv = resolve_node $noderef
		197
		198	Takes an unresolved node reference that may contain hostnames and
		199	abbreviated IDs, resolves all of them and returns a resolved node
		200	reference.
		201
		202	In addition to C<address:port> pairs allowed in resolved noderefs, the
		203	following forms are supported:
		204
		205	=over 4
		206
		207	=item the empty string
		208
		209	An empty-string component gets resolved as if the default port (4040) was
		210	specified.
		211
		212	=item naked port numbers (e.g. C<1234>)
		213
		214	These are resolved by prepending the local nodename and a colon, to be
		215	further resolved.
		216
		217	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		218
		219	These are resolved by using AnyEvent::DNS to resolve them, optionally
		220	looking up SRV records for the C<aemp=4040> port, if no port was
		221	specified.
		222
		223	=back
		224
		225	=item $SELF
		226
		227	Contains the current port id while executing C<rcv> callbacks or C<psub>
		228	blocks.
		229
		230	=item SELF, %SELF, @SELF...
		231
		232	Due to some quirks in how perl exports variables, it is impossible to
		233	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		234	module, but only C<$SELF> is currently used.
		235
155	=item snd $portid, type => @data	236	=item snd $port, type => @data
156		237
157	=item snd $portid, @msg	238	=item snd $port, @msg
158		239
159	Send the given message to the given port ID, which can identify either a	240	Send the given message to the given port ID, which can identify either
160	local or a remote port.	241	a local or a remote port, and can be either a string or soemthignt hat
		242	stringifies a sa port ID (such as a port object :).
161		243
162	While the message can be about anything, it is highly recommended to use	244	While the message can be about anything, it is highly recommended to use a
163	a constant string as first element.	245	string as first element (a portid, or some word that indicates a request
		246	type etc.).
164		247
165	The message data effectively becomes read-only after a call to this	248	The message data effectively becomes read-only after a call to this
166	function: modifying any argument is not allowed and can cause many	249	function: modifying any argument is not allowed and can cause many
167	problems.	250	problems.
168		251
…		…
170	JSON is used, then only strings, numbers and arrays and hashes consisting	253	JSON is used, then only strings, numbers and arrays and hashes consisting
171	of those are allowed (no objects). When Storable is used, then anything	254	of those are allowed (no objects). When Storable is used, then anything
172	that Storable can serialise and deserialise is allowed, and for the local	255	that Storable can serialise and deserialise is allowed, and for the local
173	node, anything can be passed.	256	node, anything can be passed.
174		257
175	=cut	258	=item $local_port = port
176		259
177	sub snd(@) {	260	Create a new local port object that can be used either as a pattern
178	my ($noderef, $port) = split /#/, shift, 2;	261	matching port ("full port") or a single-callback port ("miniport"),
		262	depending on how C<rcv> callbacks are bound to the object.
179		263
180	add_node $noderef	264	=item $port = port { my @msg = @_; $finished }
181	unless exists $NODE{$noderef};
182		265
183	$NODE{$noderef}->send (["$port", [@_]]);	266	Creates a "miniport", that is, a very lightweight port without any pattern
		267	matching behind it, and returns its ID. Semantically the same as creating
		268	a port and calling C<rcv $port, $callback> on it.
		269
		270	The block will be called for every message received on the port. When the
		271	callback returns a true value its job is considered "done" and the port
		272	will be destroyed. Otherwise it will stay alive.
		273
		274	The message will be passed as-is, no extra argument (i.e. no port id) will
		275	be passed to the callback.
		276
		277	If you need the local port id in the callback, this works nicely:
		278
		279	my $port; $port = port {
		280	snd $otherport, reply => $port;
		281	};
		282
		283	=cut
		284
		285	sub rcv($@);
		286
		287	sub port(;&) {
		288	my $id = "$UNIQ." . $ID++;
		289	my $port = "$NODE#$id";
		290
		291	if (@_) {
		292	rcv $port, shift;
		293	} else {
		294	$PORT{$id} = sub { }; # nop
		295	}
		296
		297	$port
184	}	298	}
185		299
		300	=item reg $port, $name
		301
		302	Registers the given port under the name C<$name>. If the name already
		303	exists it is replaced.
		304
		305	A port can only be registered under one well known name.
		306
		307	A port automatically becomes unregistered when it is killed.
		308
		309	=cut
		310
		311	sub reg(@) {
		312	my ($port, $name) = @_;
		313
		314	$REG{$name} = $port;
		315	}
		316
186	=item rcv $portid, type => $callback->(@msg)	317	=item rcv $port, $callback->(@msg)
187		318
		319	Replaces the callback on the specified miniport (after converting it to
		320	one if required).
		321
		322	=item rcv $port, tagstring => $callback->(@msg), ...
		323
188	=item rcv $portid, $smartmatch => $callback->(@msg)	324	=item rcv $port, $smartmatch => $callback->(@msg), ...
189		325
190	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	326	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
191		327
192	Register a callback on the port identified by C<$portid>, which I<must> be	328	Register callbacks to be called on matching messages on the given full
193	a local port.	329	port (after converting it to one if required).
194		330
195	The callback has to return a true value when its work is done, after	331	The callback has to return a true value when its work is done, after
196	which is will be removed, or a false value in which case it will stay	332	which is will be removed, or a false value in which case it will stay
197	registered.	333	registered.
198		334
		335	The global C<$SELF> (exported by this module) contains C<$port> while
		336	executing the callback.
		337
		338	Runtime errors wdurign callback execution will result in the port being
		339	C<kil>ed.
		340
199	If the match is an array reference, then it will be matched against the	341	If the match is an array reference, then it will be matched against the
200	first elements of the message, otherwise only the first element is being	342	first elements of the message, otherwise only the first element is being
201	matched.	343	matched.
202		344
203	Any element in the match that is specified as C<_any_> (a function	345	Any element in the match that is specified as C<_any_> (a function
…		…
208	also the most efficient match (by far).	350	also the most efficient match (by far).
209		351
210	=cut	352	=cut
211		353
212	sub rcv($@) {	354	sub rcv($@) {
213	my ($port, $match, $cb) = @_;	355	my $port = shift;
214
215	my $port = $PORT{$port}
216	or do {
217	my ($noderef, $lport) = split /#/, $port;	356	my ($noderef, $portid) = split /#/, $port, 2;
218	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	357
		358	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
219	or Carp::croak "$port: can only rcv on local ports";	359	or Carp::croak "$port: rcv can only be called on local ports, caught";
220		360
221	$PORT{$lport}	361	if (@_ == 1) {
222	or Carp::croak "$port: port does not exist";	362	my $cb = shift;
		363	delete $PORT_DATA{$portid};
		364	$PORT{$portid} = sub {
		365	local $SELF = $port;
		366	eval {
223		367	&$cb
224	$PORT{$port} = $PORT{$lport} # also return	368	and kil $port;
		369	};
		370	_self_die if $@;
225	};	371	};
226
227	if (!ref $match) {
228	push @{ $port->{rc0}{$match} }, [$cb];
229	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
230	my ($type, @match) = @$match;
231	@match
232	? push @{ $port->{rcv}{$match->[0]} }, [$cb, \@match]
233	: push @{ $port->{rc0}{$match->[0]} }, [$cb];
234	} else {	372	} else {
235	push @{ $port->{any} }, [$cb, $match];	373	my $self = $PORT_DATA{$portid} \|\|= do {
236	}	374	my $self = bless {
237	}	375	id => $port,
		376	}, "AnyEvent::MP::Port";
238		377
239	sub _inject {	378	$PORT{$portid} = sub {
240	my ($port, $msg) = @{+shift};	379	local $SELF = $port;
241		380
242	$port = $PORT{$port}	381	eval {
243	or return;	382	for (@{ $self->{rc0}{$_[0]} }) {
244
245	@_ = @$msg;
246
247	for (@{ $port->{rc0}{$msg->[0]} }) {
248	$_ && &{$_->[0]}	383	$_ && &{$_->[0]}
249	&& undef $_;	384	&& undef $_;
250	}
251
252	for (@{ $port->{rcv}{$msg->[0]} }) {
253	$_ && [@_[1..$#{$_->[1]}]] ~~ $_->[1]
254	&& &{$_->[0]}
255	&& undef $_;
256	}
257
258	for (@{ $port->{any} }) {
259	$_ && [@_[0..$#{$_->[1]}]] ~~ $_->[1]
260	&& &{$_->[0]}
261	&& undef $_;
262	}
263	}
264
265	sub normalise_noderef($) {
266	my ($noderef) = @_;
267
268	my $cv = AE::cv;
269	my @res;
270
271	$cv->begin (sub {
272	my %seen;
273	my @refs;
274	for (sort { $a->[0] <=> $b->[0] } @res) {
275	push @refs, $_->[1] unless $seen{$_->[1]}++
276	}
277	shift->send (join ",", @refs);
278	});
279
280	$noderef = $DEFAULT_PORT unless length $noderef;
281
282	my $idx;
283	for my $t (split /,/, $noderef) {
284	my $pri = ++$idx;
285
286	#TODO: this should be outside normalise_noderef and in become_public
287	if ($t =~ /^\d*$/) {
288	my $nodename = (POSIX::uname)[1];
289
290	$cv->begin;
291	AnyEvent::Socket::resolve_sockaddr $nodename, $t \|\| "aemp=$DEFAULT_PORT", "tcp", 0, undef, sub {
292	for (@_) {
293	my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3];
294	push @res, [
295	$pri += 1e-5,
296	AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service
297	];	385	}
		386
		387	for (@{ $self->{rcv}{$_[0]} }) {
		388	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		389	&& &{$_->[0]}
		390	&& undef $_;
		391	}
		392
		393	for (@{ $self->{any} }) {
		394	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		395	&& &{$_->[0]}
		396	&& undef $_;
		397	}
298	}	398	};
299	$cv->end;	399	_self_die if $@;
300	};	400	};
301		401
302	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;	402	$self
303	#	403	};
304	# for (@ipv4) {	404
305	# push @res, [	405	"AnyEvent::MP::Port" eq ref $self
306	# $pri,	406	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
307	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,	407
308	# ];	408	while (@_) {
309	# }	409	my ($match, $cb) = splice @_, 0, 2;
		410
		411	if (!ref $match) {
		412	push @{ $self->{rc0}{$match} }, [$cb];
		413	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		414	my ($type, @match) = @$match;
		415	@match
		416	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		417	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
310	} else {	418	} else {
311	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	419	push @{ $self->{any} }, [$cb, $match];
312	or Carp::croak "$t: unparsable transport descriptor";
313
314	$cv->begin;
315	AnyEvent::Socket::resolve_sockaddr $host, $port, "tcp", 0, undef, sub {
316	for (@_) {
317	my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3];
318	push @res, [
319	$pri += 1e-5,
320	AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service
321	];
322	}
323	$cv->end;
324	}	420	}
325	}	421	}
326	}	422	}
327		423
328	$cv->end;	424	$port
329
330	$cv
331	}	425	}
332		426
333	sub become_public {	427	=item $closure = psub { BLOCK }
334	return if $PUBLIC;
335		428
336	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	429	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
337	my @args = @_;	430	closure is executed, sets up the environment in the same way as in C<rcv>
		431	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
338		432
339	$NODE = (normalise_noderef $noderef)->recv;	433	This is useful when you register callbacks from C<rcv> callbacks:
340		434
341	for my $t (split /,/, $NODE) {	435	rcv delayed_reply => sub {
342	$NODE{$t} = $NODE{""};	436	my ($delay, @reply) = @_;
343		437	my $timer = AE::timer $delay, 0, psub {
344	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	438	snd @reply, $SELF;
345
346	$LISTENER{$t} = AnyEvent::MP::Transport::mp_server $host, $port,
347	@args,
348	on_error => sub {
349	die "on_error<@_>\n";#d#
350	},
351	on_connect => sub {
352	my ($tp) = @_;
353
354	$NODE{$tp->{remote_id}} = $_[0];
355	},
356	sub {
357	my ($tp) = @_;
358
359	$NODE{"$tp->{peerhost}:$tp->{peerport}"} = $tp;
360	},
361	;	439	};
		440	};
		441
		442	=cut
		443
		444	sub psub(&) {
		445	my $cb = shift;
		446
		447	my $port = $SELF
		448	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		449
		450	sub {
		451	local $SELF = $port;
		452
		453	if (wantarray) {
		454	my @res = eval { &$cb };
		455	_self_die if $@;
		456	@res
		457	} else {
		458	my $res = eval { &$cb };
		459	_self_die if $@;
		460	$res
		461	}
362	}	462	}
363
364	$PUBLIC = 1;
365	}	463	}
		464
		465	=item $guard = mon $port, $cb->(@reason)
		466
		467	=item $guard = mon $port, $otherport
		468
		469	=item $guard = mon $port, $otherport, @msg
		470
		471	Monitor the given port and do something when the port is killed.
		472
		473	In the first form, the callback is simply called with any number
		474	of C<@reason> elements (no @reason means that the port was deleted
		475	"normally"). Note also that I<< the callback B<must> never die >>, so use
		476	C<eval> if unsure.
		477
		478	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
		479	a @reason was specified, i.e. on "normal" kils nothing happens, while
		480	under all other conditions, the other port is killed with the same reason.
		481
		482	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
		483
		484	Example: call a given callback when C<$port> is killed.
		485
		486	mon $port, sub { warn "port died because of <@_>\n" };
		487
		488	Example: kill ourselves when C<$port> is killed abnormally.
		489
		490	mon $port, $self;
		491
		492	Example: send us a restart message another C<$port> is killed.
		493
		494	mon $port, $self => "restart";
		495
		496	=cut
		497
		498	sub mon {
		499	my ($noderef, $port) = split /#/, shift, 2;
		500
		501	my $node = $NODE{$noderef} \|\| add_node $noderef;
		502
		503	my $cb = shift;
		504
		505	unless (ref $cb) {
		506	if (@_) {
		507	# send a kill info message
		508	my (@msg) = ($cb, @_);
		509	$cb = sub { snd @msg, @_ };
		510	} else {
		511	# simply kill other port
		512	my $port = $cb;
		513	$cb = sub { kil $port, @_ if @_ };
		514	}
		515	}
		516
		517	$node->monitor ($port, $cb);
		518
		519	defined wantarray
		520	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		521	}
		522
		523	=item $guard = mon_guard $port, $ref, $ref...
		524
		525	Monitors the given C<$port> and keeps the passed references. When the port
		526	is killed, the references will be freed.
		527
		528	Optionally returns a guard that will stop the monitoring.
		529
		530	This function is useful when you create e.g. timers or other watchers and
		531	want to free them when the port gets killed:
		532
		533	$port->rcv (start => sub {
		534	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		535	undef $timer if 0.9 < rand;
		536	});
		537	});
		538
		539	=cut
		540
		541	sub mon_guard {
		542	my ($port, @refs) = @_;
		543
		544	mon $port, sub { 0 && @refs }
		545	}
		546
		547	=item lnk $port1, $port2
		548
		549	Link two ports. This is simply a shorthand for:
		550
		551	mon $port1, $port2;
		552	mon $port2, $port1;
		553
		554	It means that if either one is killed abnormally, the other one gets
		555	killed as well.
		556
		557	=item kil $port[, @reason]
		558
		559	Kill the specified port with the given C<@reason>.
		560
		561	If no C<@reason> is specified, then the port is killed "normally" (linked
		562	ports will not be kileld, or even notified).
		563
		564	Otherwise, linked ports get killed with the same reason (second form of
		565	C<mon>, see below).
		566
		567	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		568	will be reported as reason C<< die => $@ >>.
		569
		570	Transport/communication errors are reported as C<< transport_error =>
		571	$message >>.
366		572
367	=back	573	=back
368		574
369	=head1 NODE MESSAGES	575	=head1 NODE MESSAGES
370		576
371	Nodes understand the following messages sent to them. Many of them take	577	Nodes understand the following messages sent to them. Many of them take
372	arguments called C<@reply>, which will simply be used to compose a reply	578	arguments called C<@reply>, which will simply be used to compose a reply
373	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	579	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
374	the remaining arguments are simply the message data.	580	the remaining arguments are simply the message data.
375		581
		582	While other messages exist, they are not public and subject to change.
		583
376	=over 4	584	=over 4
377		585
378	=cut	586	=cut
379		587
380	#############################################################################	588	=item lookup => $name, @reply
381	# self node code
382		589
383	sub _new_port($) {	590	Replies with the port ID of the specified well-known port, or C<undef>.
384	my ($name) = @_;
385		591
386	my ($noderef, $portname) = split /#/, $name;	592	=item devnull => ...
387		593
388	$PORT{$name} =	594	Generic data sink/CPU heat conversion.
389	$PORT{$portname} = {
390	names => [$name, $portname],
391	};
392	}
393
394	$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE;
395	_new_port "";
396		595
397	=item relay => $port, @msg	596	=item relay => $port, @msg
398		597
399	Simply forwards the message to the given port.	598	Simply forwards the message to the given port.
400
401	=cut
402
403	rcv "", relay => \&snd;
404		599
405	=item eval => $string[ @reply]	600	=item eval => $string[ @reply]
406		601
407	Evaluates the given string. If C<@reply> is given, then a message of the	602	Evaluates the given string. If C<@reply> is given, then a message of the
408	form C<@reply, $@, @evalres> is sent.	603	form C<@reply, $@, @evalres> is sent.
409		604
410	Example: crash another node.	605	Example: crash another node.
411		606
412	snd $othernode, eval => "exit";	607	snd $othernode, eval => "exit";
413		608
414	=cut
415
416	rcv "", eval => sub {
417	my (undef, $string, @reply) = @_;
418	my @res = eval $string;
419	snd @reply, "$@", @res if @reply;
420	};
421
422	=item time => @reply	609	=item time => @reply
423		610
424	Replies the the current node time to C<@reply>.	611	Replies the the current node time to C<@reply>.
425		612
426	Example: tell the current node to send the current time to C<$myport> in a	613	Example: tell the current node to send the current time to C<$myport> in a
427	C<timereply> message.	614	C<timereply> message.
428		615
429	snd $NODE, time => $myport, timereply => 1, 2;	616	snd $NODE, time => $myport, timereply => 1, 2;
430	# => snd $myport, timereply => 1, 2, <time>	617	# => snd $myport, timereply => 1, 2, <time>
431		618
432	=cut	619	=back
433		620
434	rcv "", time => sub { shift; snd @_, AE::time };	621	=head1 AnyEvent::MP vs. Distributed Erlang
		622
		623	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node
		624	== aemp node, erlang process == aemp port), so many of the documents and
		625	programming techniques employed by erlang apply to AnyEvent::MP. Here is a
		626	sample:
		627
		628	http://www.erlang.se/doc/programming_rules.shtml
		629	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		630	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
		631	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		632
		633	Despite the similarities, there are also some important differences:
		634
		635	=over 4
		636
		637	=item * Node references contain the recipe on how to contact them.
		638
		639	Erlang relies on special naming and DNS to work everywhere in the
		640	same way. AEMP relies on each node knowing it's own address(es), with
		641	convenience functionality.
		642
		643	This means that AEMP requires a less tightly controlled environment at the
		644	cost of longer node references and a slightly higher management overhead.
		645
		646	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		647
		648	Erlang uses processes that selctively receive messages, and therefore
		649	needs a queue. AEMP is event based, queuing messages would serve no useful
		650	purpose.
		651
		652	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		653
		654	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		655
		656	Sending messages in erlang is synchronous and blocks the process. AEMP
		657	sends are immediate, connection establishment is handled in the
		658	background.
		659
		660	=item * Erlang can silently lose messages, AEMP cannot.
		661
		662	Erlang makes few guarantees on messages delivery - messages can get lost
		663	without any of the processes realising it (i.e. you send messages a, b,
		664	and c, and the other side only receives messages a and c).
		665
		666	AEMP guarantees correct ordering, and the guarantee that there are no
		667	holes in the message sequence.
		668
		669	=item * In erlang, processes can be declared dead and later be found to be
		670	alive.
		671
		672	In erlang it can happen that a monitored process is declared dead and
		673	linked processes get killed, but later it turns out that the process is
		674	still alive - and can receive messages.
		675
		676	In AEMP, when port monitoring detects a port as dead, then that port will
		677	eventually be killed - it cannot happen that a node detects a port as dead
		678	and then later sends messages to it, finding it is still alive.
		679
		680	=item * Erlang can send messages to the wrong port, AEMP does not.
		681
		682	In erlang it is quite possible that a node that restarts reuses a process
		683	ID known to other nodes for a completely different process, causing
		684	messages destined for that process to end up in an unrelated process.
		685
		686	AEMP never reuses port IDs, so old messages or old port IDs floating
		687	around in the network will not be sent to an unrelated port.
		688
		689	=item * Erlang uses unprotected connections, AEMP uses secure
		690	authentication and can use TLS.
		691
		692	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		693	securely authenticate nodes.
		694
		695	=item * The AEMP protocol is optimised for both text-based and binary
		696	communications.
		697
		698	The AEMP protocol, unlike the erlang protocol, supports both
		699	language-independent text-only protocols (good for debugging) and binary,
		700	language-specific serialisers (e.g. Storable).
		701
		702	It has also been carefully designed to be implementable in other languages
		703	with a minimum of work while gracefully degrading fucntionality to make the
		704	protocol simple.
435		705
436	=back	706	=back
437		707
438	=head1 SEE ALSO	708	=head1 SEE ALSO
439		709

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Revision 1.5 by root, Sat Aug 1 07:44:02 2009 UTC vs.
Revision 1.34 by root, Wed Aug 5 23:50:46 2009 UTC