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

Comparing cvsroot/AnyEvent-MP/MP.pm (file contents):
Revision 1.4 by root, Sat Aug 1 07:36:30 2009 UTC vs.
Revision 1.33 by root, Wed Aug 5 22:40:51 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", $$, time; # per-process/node unique cookie	130	Extracts and returns the noderef from a portid or a noderef.
116	our $PUBLIC = 0;
117	our $NODE;
118	our $PORT;
119		131
120	our %NODE; # node id to transport mapping, or "undef", for local node	132	=item $cv = resolve_node $noderef
121	our %PORT; # local ports
122	our %LISTENER; # local transports
123		133
124	sub NODE() { $NODE }	134	Takes an unresolved node reference that may contain hostnames and
		135	abbreviated IDs, resolves all of them and returns a resolved node
		136	reference.
125		137
126	{	138	In addition to C<address:port> pairs allowed in resolved noderefs, the
127	use POSIX ();	139	following forms are supported:
128	my $nodename = (POSIX::uname)[1];
129	$NODE = "$$\@$nodename";
130	}
131		140
132	sub _ANY_() { 1 }	141	=over 4
133	sub _any_() { \&_ANY_ }
134		142
135	sub add_node {	143	=item the empty string
136	my ($noderef) = @_;
137		144
138	return $NODE{$noderef}	145	An empty-string component gets resolved as if the default port (4040) was
139	if exists $NODE{$noderef};	146	specified.
140		147
141	for (split /,/, $noderef) {	148	=item naked port numbers (e.g. C<1234>)
142	return $NODE{$noderef} = $NODE{$_}
143	if exists $NODE{$_};
144	}
145		149
146	# for indirect sends, use a different class	150	These are resolved by prepending the local nodename and a colon, to be
147	my $node = new AnyEvent::MP::Node::Direct $noderef;	151	further resolved.
148		152
149	$NODE{$_} = $node	153	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
150	for $noderef, split /,/, $noderef;
151		154
152	$node	155	These are resolved by using AnyEvent::DNS to resolve them, optionally
153	}	156	looking up SRV records for the C<aemp=4040> port, if no port was
		157	specified.
154		158
		159	=back
		160
		161	=item $SELF
		162
		163	Contains the current port id while executing C<rcv> callbacks or C<psub>
		164	blocks.
		165
		166	=item SELF, %SELF, @SELF...
		167
		168	Due to some quirks in how perl exports variables, it is impossible to
		169	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		170	module, but only C<$SELF> is currently used.
		171
155	=item snd $portid, type => @data	172	=item snd $port, type => @data
156		173
157	=item snd $portid, @msg	174	=item snd $port, @msg
158		175
159	Send the given message to the given port ID, which can identify either a	176	Send the given message to the given port ID, which can identify either
160	local or a remote port.	177	a local or a remote port, and can be either a string or soemthignt hat
		178	stringifies a sa port ID (such as a port object :).
161		179
162	While the message can be about anything, it is highly recommended to use	180	While the message can be about anything, it is highly recommended to use a
163	a constant string as first element.	181	string as first element (a portid, or some word that indicates a request
		182	type etc.).
164		183
165	The message data effectively becomes read-only after a call to this	184	The message data effectively becomes read-only after a call to this
166	function: modifying any argument is not allowed and can cause many	185	function: modifying any argument is not allowed and can cause many
167	problems.	186	problems.
168		187
…		…
170	JSON is used, then only strings, numbers and arrays and hashes consisting	189	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	190	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	191	that Storable can serialise and deserialise is allowed, and for the local
173	node, anything can be passed.	192	node, anything can be passed.
174		193
175	=cut	194	=item $local_port = port
176		195
177	sub snd(@) {	196	Create a new local port object that can be used either as a pattern
178	my ($noderef, $port) = split /#/, shift, 2;	197	matching port ("full port") or a single-callback port ("miniport"),
		198	depending on how C<rcv> callbacks are bound to the object.
179		199
180	add_node $noderef	200	=item $port = port { my @msg = @_; $finished }
181	unless exists $NODE{$noderef};
182		201
183	$NODE{$noderef}->send (["$port", [@_]]);	202	Creates a "miniport", that is, a very lightweight port without any pattern
		203	matching behind it, and returns its ID. Semantically the same as creating
		204	a port and calling C<rcv $port, $callback> on it.
		205
		206	The block will be called for every message received on the port. When the
		207	callback returns a true value its job is considered "done" and the port
		208	will be destroyed. Otherwise it will stay alive.
		209
		210	The message will be passed as-is, no extra argument (i.e. no port id) will
		211	be passed to the callback.
		212
		213	If you need the local port id in the callback, this works nicely:
		214
		215	my $port; $port = port {
		216	snd $otherport, reply => $port;
		217	};
		218
		219	=cut
		220
		221	sub rcv($@);
		222
		223	sub port(;&) {
		224	my $id = "$UNIQ." . $ID++;
		225	my $port = "$NODE#$id";
		226
		227	if (@_) {
		228	rcv $port, shift;
		229	} else {
		230	$PORT{$id} = sub { }; # nop
		231	}
		232
		233	$port
184	}	234	}
185		235
		236	=item reg $port, $name
		237
		238	Registers the given port under the name C<$name>. If the name already
		239	exists it is replaced.
		240
		241	A port can only be registered under one well known name.
		242
		243	A port automatically becomes unregistered when it is killed.
		244
		245	=cut
		246
		247	sub reg(@) {
		248	my ($port, $name) = @_;
		249
		250	$REG{$name} = $port;
		251	}
		252
186	=item rcv $portid, type => $callback->(@msg)	253	=item rcv $port, $callback->(@msg)
187		254
		255	Replaces the callback on the specified miniport (after converting it to
		256	one if required).
		257
		258	=item rcv $port, tagstring => $callback->(@msg), ...
		259
188	=item rcv $portid, $smartmatch => $callback->(@msg)	260	=item rcv $port, $smartmatch => $callback->(@msg), ...
189		261
190	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	262	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
191		263
192	Register a callback on the port identified by C<$portid>, which I<must> be	264	Register callbacks to be called on matching messages on the given full
193	a local port.	265	port (after converting it to one if required).
194		266
195	The callback has to return a true value when its work is done, after	267	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	268	which is will be removed, or a false value in which case it will stay
197	registered.	269	registered.
198		270
		271	The global C<$SELF> (exported by this module) contains C<$port> while
		272	executing the callback.
		273
		274	Runtime errors wdurign callback execution will result in the port being
		275	C<kil>ed.
		276
199	If the match is an array reference, then it will be matched against the	277	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	278	first elements of the message, otherwise only the first element is being
201	matched.	279	matched.
202		280
203	Any element in the match that is specified as C<_any_> (a function	281	Any element in the match that is specified as C<_any_> (a function
…		…
208	also the most efficient match (by far).	286	also the most efficient match (by far).
209		287
210	=cut	288	=cut
211		289
212	sub rcv($@) {	290	sub rcv($@) {
213	my ($port, $match, $cb) = @_;	291	my $port = shift;
214
215	my $port = $PORT{$port}
216	or do {
217	my ($noderef, $lport) = split /#/, $port;	292	my ($noderef, $portid) = split /#/, $port, 2;
218	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	293
		294	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
219	or Carp::croak "$port: can only rcv on local ports";	295	or Carp::croak "$port: rcv can only be called on local ports, caught";
220		296
221	$PORT{$lport}	297	if (@_ == 1) {
222	or Carp::croak "$port: port does not exist";	298	my $cb = shift;
		299	delete $PORT_DATA{$portid};
		300	$PORT{$portid} = sub {
		301	local $SELF = $port;
		302	eval {
223		303	&$cb
224	$PORT{$port} = $PORT{$lport} # also return	304	and kil $port;
		305	};
		306	_self_die if $@;
225	};	307	};
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 {	308	} else {
235	push @{ $port->{any} }, [$cb, $match];	309	my $self = $PORT_DATA{$portid} \|\|= do {
236	}	310	my $self = bless {
237	}	311	id => $port,
		312	}, "AnyEvent::MP::Port";
238		313
239	sub _inject {	314	$PORT{$portid} = sub {
240	my ($port, $msg) = @{+shift};	315	local $SELF = $port;
241		316
242	$port = $PORT{$port}	317	eval {
243	or return;	318	for (@{ $self->{rc0}{$_[0]} }) {
244
245	@_ = @$msg;
246
247	for (@{ $port->{rc0}{$msg->[0]} }) {
248	$_ && &{$_->[0]}	319	$_ && &{$_->[0]}
249	&& undef $_;	320	&& 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	];	321	}
		322
		323	for (@{ $self->{rcv}{$_[0]} }) {
		324	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		325	&& &{$_->[0]}
		326	&& undef $_;
		327	}
		328
		329	for (@{ $self->{any} }) {
		330	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		331	&& &{$_->[0]}
		332	&& undef $_;
		333	}
298	}	334	};
299	$cv->end;	335	_self_die if $@;
300	};	336	};
301		337
302	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;	338	$self
303	#	339	};
304	# for (@ipv4) {	340
305	# push @res, [	341	"AnyEvent::MP::Port" eq ref $self
306	# $pri,	342	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
307	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,	343
308	# ];	344	while (@_) {
309	# }	345	my ($match, $cb) = splice @_, 0, 2;
		346
		347	if (!ref $match) {
		348	push @{ $self->{rc0}{$match} }, [$cb];
		349	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		350	my ($type, @match) = @$match;
		351	@match
		352	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		353	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
310	} else {	354	} else {
311	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	355	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	}	356	}
325	}	357	}
326	}	358	}
327		359
328	$cv->end;	360	$port
329
330	$cv
331	}	361	}
332		362
333	sub become_public {	363	=item $closure = psub { BLOCK }
334	return if $PUBLIC;
335		364
336	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	365	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
337	my @args = @_;	366	closure is executed, sets up the environment in the same way as in C<rcv>
		367	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
338		368
339	$NODE = (normalise_noderef $noderef)->recv;	369	This is useful when you register callbacks from C<rcv> callbacks:
340		370
341	for my $t (split /,/, $NODE) {	371	rcv delayed_reply => sub {
342	$NODE{$t} = $NODE{""};	372	my ($delay, @reply) = @_;
343		373	my $timer = AE::timer $delay, 0, psub {
344	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	374	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	;	375	};
		376	};
		377
		378	=cut
		379
		380	sub psub(&) {
		381	my $cb = shift;
		382
		383	my $port = $SELF
		384	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		385
		386	sub {
		387	local $SELF = $port;
		388
		389	if (wantarray) {
		390	my @res = eval { &$cb };
		391	_self_die if $@;
		392	@res
		393	} else {
		394	my $res = eval { &$cb };
		395	_self_die if $@;
		396	$res
		397	}
362	}	398	}
363
364	$PUBLIC = 1;
365	}	399	}
366		400
		401	=item $guard = mon $port, $cb->(@reason)
		402
		403	=item $guard = mon $port, $otherport
		404
		405	=item $guard = mon $port, $otherport, @msg
		406
		407	Monitor the given port and do something when the port is killed.
		408
		409	In the first form, the callback is simply called with any number
		410	of C<@reason> elements (no @reason means that the port was deleted
		411	"normally"). Note also that I<< the callback B<must> never die >>, so use
		412	C<eval> if unsure.
		413
		414	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
		415	a @reason was specified, i.e. on "normal" kils nothing happens, while
		416	under all other conditions, the other port is killed with the same reason.
		417
		418	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
		419
		420	Example: call a given callback when C<$port> is killed.
		421
		422	mon $port, sub { warn "port died because of <@_>\n" };
		423
		424	Example: kill ourselves when C<$port> is killed abnormally.
		425
		426	mon $port, $self;
		427
		428	Example: send us a restart message another C<$port> is killed.
		429
		430	mon $port, $self => "restart";
		431
		432	=cut
		433
		434	sub mon {
		435	my ($noderef, $port) = split /#/, shift, 2;
		436
		437	my $node = $NODE{$noderef} \|\| add_node $noderef;
		438
		439	my $cb = shift;
		440
		441	unless (ref $cb) {
		442	if (@_) {
		443	# send a kill info message
		444	my (@msg) = ($cb, @_);
		445	$cb = sub { snd @msg, @_ };
		446	} else {
		447	# simply kill other port
		448	my $port = $cb;
		449	$cb = sub { kil $port, @_ if @_ };
		450	}
		451	}
		452
		453	$node->monitor ($port, $cb);
		454
		455	defined wantarray
		456	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		457	}
		458
		459	=item $guard = mon_guard $port, $ref, $ref...
		460
		461	Monitors the given C<$port> and keeps the passed references. When the port
		462	is killed, the references will be freed.
		463
		464	Optionally returns a guard that will stop the monitoring.
		465
		466	This function is useful when you create e.g. timers or other watchers and
		467	want to free them when the port gets killed:
		468
		469	$port->rcv (start => sub {
		470	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		471	undef $timer if 0.9 < rand;
		472	});
		473	});
		474
		475	=cut
		476
		477	sub mon_guard {
		478	my ($port, @refs) = @_;
		479
		480	mon $port, sub { 0 && @refs }
		481	}
		482
		483	=item lnk $port1, $port2
		484
		485	Link two ports. This is simply a shorthand for:
		486
		487	mon $port1, $port2;
		488	mon $port2, $port1;
		489
		490	It means that if either one is killed abnormally, the other one gets
		491	killed as well.
		492
		493	=item kil $port[, @reason]
		494
		495	Kill the specified port with the given C<@reason>.
		496
		497	If no C<@reason> is specified, then the port is killed "normally" (linked
		498	ports will not be kileld, or even notified).
		499
		500	Otherwise, linked ports get killed with the same reason (second form of
		501	C<mon>, see below).
		502
		503	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		504	will be reported as reason C<< die => $@ >>.
		505
		506	Transport/communication errors are reported as C<< transport_error =>
		507	$message >>.
		508
367	=back	509	=back
368		510
		511	=head1 FUNCTIONS FOR NODES
		512
		513	=over 4
		514
		515	=item initialise_node $noderef, $seednode, $seednode...
		516
		517	=item initialise_node "slave/", $master, $master...
		518
		519	Initialises a node - must be called exactly once before calling other
		520	AnyEvent::MP functions when talking to other nodes is required.
		521
		522	All arguments are noderefs, which can be either resolved or unresolved.
		523
		524	There are two types of networked nodes, public nodes and slave nodes:
		525
		526	=over 4
		527
		528	=item public nodes
		529
		530	For public nodes, C<$noderef> must either be a (possibly unresolved)
		531	noderef, in which case it will be resolved, or C<undef> (or missing), in
		532	which case the noderef will be guessed.
		533
		534	Afterwards, the node will bind itself on all endpoints and try to connect
		535	to all additional C<$seednodes> that are specified. Seednodes are optional
		536	and can be used to quickly bootstrap the node into an existing network.
		537
		538	=item slave nodes
		539
		540	When the C<$noderef> is the special string C<slave/>, then the node will
		541	become a slave node. Slave nodes cannot be contacted from outside and will
		542	route most of their traffic to the master node that they attach to.
		543
		544	At least one additional noderef is required: The node will try to connect
		545	to all of them and will become a slave attached to the first node it can
		546	successfully connect to.
		547
		548	=back
		549
		550	This function will block until all nodes have been resolved and, for slave
		551	nodes, until it has successfully established a connection to a master
		552	server.
		553
		554	Example: become a public node listening on the default node.
		555
		556	initialise_node;
		557
		558	Example: become a public node, and try to contact some well-known master
		559	servers to become part of the network.
		560
		561	initialise_node undef, "master1", "master2";
		562
		563	Example: become a public node listening on port C<4041>.
		564
		565	initialise_node 4041;
		566
		567	Example: become a public node, only visible on localhost port 4044.
		568
		569	initialise_node "locahost:4044";
		570
		571	Example: become a slave node to any of the specified master servers.
		572
		573	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		574
		575	=cut
		576
		577	=back
		578
369	=head1 NODE MESSAGES	579	=head1 NODE MESSAGES
370		580
371	Nodes understand the following messages sent to them:	581	Nodes understand the following messages sent to them. Many of them take
		582	arguments called C<@reply>, which will simply be used to compose a reply
		583	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
		584	the remaining arguments are simply the message data.
		585
		586	While other messages exist, they are not public and subject to change.
372		587
373	=over 4	588	=over 4
374		589
375	=cut	590	=cut
376		591
377	#############################################################################	592	=item lookup => $name, @reply
378	# self node code
379		593
380	sub _new_port($) {	594	Replies with the port ID of the specified well-known port, or C<undef>.
381	my ($name) = @_;
382		595
383	my ($noderef, $portname) = split /#/, $name;	596	=item devnull => ...
384		597
385	$PORT{$name} =	598	Generic data sink/CPU heat conversion.
386	$PORT{$portname} = {
387	names => [$name, $portname],
388	};
389	}
390
391	$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE;
392	_new_port "";
393		599
394	=item relay => $port, @msg	600	=item relay => $port, @msg
395		601
396	Simply forwards the message to the given port.	602	Simply forwards the message to the given port.
397		603
398	=cut
399
400	rcv "", relay => \&snd;
401
402	=item eval => $string[ @reply]	604	=item eval => $string[ @reply]
403		605
404	Evaluates the given string. If C<@reply> is given, then a message of the	606	Evaluates the given string. If C<@reply> is given, then a message of the
405	form C<@reply, $@, @evalres> is sent (C<$reply[0]> is the port to reply to).	607	form C<@reply, $@, @evalres> is sent.
406		608
407	=cut	609	Example: crash another node.
408		610
409	rcv "", eval => sub {	611	snd $othernode, eval => "exit";
410	my (undef, $string, @reply) = @_;
411	my @res = eval $string;
412	snd @reply, "$@", @res if @reply;
413	};
414		612
415	=item time => @reply	613	=item time => @reply
416		614
417	Replies the the current node time to C<@reply>.	615	Replies the the current node time to C<@reply>.
418		616
419	=cut	617	Example: tell the current node to send the current time to C<$myport> in a
		618	C<timereply> message.
420		619
421	rcv "", time => sub { shift; snd @_, AE::time };	620	snd $NODE, time => $myport, timereply => 1, 2;
		621	# => snd $myport, timereply => 1, 2, <time>
		622
		623	=back
		624
		625	=head1 AnyEvent::MP vs. Distributed Erlang
		626
		627	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node
		628	== aemp node, erlang process == aemp port), so many of the documents and
		629	programming techniques employed by erlang apply to AnyEvent::MP. Here is a
		630	sample:
		631
		632	http://www.erlang.se/doc/programming_rules.shtml
		633	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		634	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
		635	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		636
		637	Despite the similarities, there are also some important differences:
		638
		639	=over 4
		640
		641	=item * Node references contain the recipe on how to contact them.
		642
		643	Erlang relies on special naming and DNS to work everywhere in the
		644	same way. AEMP relies on each node knowing it's own address(es), with
		645	convenience functionality.
		646
		647	This means that AEMP requires a less tightly controlled environment at the
		648	cost of longer node references and a slightly higher management overhead.
		649
		650	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		651
		652	Erlang uses processes that selctively receive messages, and therefore
		653	needs a queue. AEMP is event based, queuing messages would serve no useful
		654	purpose.
		655
		656	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		657
		658	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		659
		660	Sending messages in erlang is synchronous and blocks the process. AEMP
		661	sends are immediate, connection establishment is handled in the
		662	background.
		663
		664	=item * Erlang can silently lose messages, AEMP cannot.
		665
		666	Erlang makes few guarantees on messages delivery - messages can get lost
		667	without any of the processes realising it (i.e. you send messages a, b,
		668	and c, and the other side only receives messages a and c).
		669
		670	AEMP guarantees correct ordering, and the guarantee that there are no
		671	holes in the message sequence.
		672
		673	=item * In erlang, processes can be declared dead and later be found to be
		674	alive.
		675
		676	In erlang it can happen that a monitored process is declared dead and
		677	linked processes get killed, but later it turns out that the process is
		678	still alive - and can receive messages.
		679
		680	In AEMP, when port monitoring detects a port as dead, then that port will
		681	eventually be killed - it cannot happen that a node detects a port as dead
		682	and then later sends messages to it, finding it is still alive.
		683
		684	=item * Erlang can send messages to the wrong port, AEMP does not.
		685
		686	In erlang it is quite possible that a node that restarts reuses a process
		687	ID known to other nodes for a completely different process, causing
		688	messages destined for that process to end up in an unrelated process.
		689
		690	AEMP never reuses port IDs, so old messages or old port IDs floating
		691	around in the network will not be sent to an unrelated port.
		692
		693	=item * Erlang uses unprotected connections, AEMP uses secure
		694	authentication and can use TLS.
		695
		696	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		697	securely authenticate nodes.
		698
		699	=item * The AEMP protocol is optimised for both text-based and binary
		700	communications.
		701
		702	The AEMP protocol, unlike the erlang protocol, supports both
		703	language-independent text-only protocols (good for debugging) and binary,
		704	language-specific serialisers (e.g. Storable).
		705
		706	It has also been carefully designed to be implementable in other languages
		707	with a minimum of work while gracefully degrading fucntionality to make the
		708	protocol simple.
422		709
423	=back	710	=back
424		711
425	=head1 SEE ALSO	712	=head1 SEE ALSO
426		713

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Revision 1.33 by root, Wed Aug 5 22:40:51 2009 UTC