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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.4 by root, Sat Aug 1 07:36:30 2009 UTC vs.
Revision 1.32 by root, Wed Aug 5 19:58:46 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 $portid
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.
		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.
154		171
155	=item snd $portid, type => @data	172	=item snd $portid, type => @data
156		173
157	=item snd $portid, @msg	174	=item snd $portid, @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 $portid = port { my @msg = @_; $finished }
181	unless exists $NODE{$noderef};
182		201
183	$NODE{$noderef}->send (["$port", [@_]]);	202	Creates a "mini port", that is, a very lightweight port without any
		203	pattern matching behind it, and returns its ID.
		204
		205	The block will be called for every message received on the port. When the
		206	callback returns a true value its job is considered "done" and the port
		207	will be destroyed. Otherwise it will stay alive.
		208
		209	The message will be passed as-is, no extra argument (i.e. no port id) will
		210	be passed to the callback.
		211
		212	If you need the local port id in the callback, this works nicely:
		213
		214	my $port; $port = port {
		215	snd $otherport, reply => $port;
		216	};
		217
		218	=cut
		219
		220	sub port(;&) {
		221	my $id = "$UNIQ." . $ID++;
		222	my $port = "$NODE#$id";
		223
		224	if (@_) {
		225	my $cb = shift;
		226	$PORT{$id} = sub {
		227	local $SELF = $port;
		228	eval {
		229	&$cb
		230	and kil $id;
		231	};
		232	_self_die if $@;
		233	};
		234	} else {
		235	my $self = bless {
		236	id => "$NODE#$id",
		237	}, "AnyEvent::MP::Port";
		238
		239	$PORT_DATA{$id} = $self;
		240	$PORT{$id} = sub {
		241	local $SELF = $port;
		242
		243	eval {
		244	for (@{ $self->{rc0}{$_[0]} }) {
		245	$_ && &{$_->[0]}
		246	&& undef $_;
		247	}
		248
		249	for (@{ $self->{rcv}{$_[0]} }) {
		250	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		251	&& &{$_->[0]}
		252	&& undef $_;
		253	}
		254
		255	for (@{ $self->{any} }) {
		256	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		257	&& &{$_->[0]}
		258	&& undef $_;
		259	}
		260	};
		261	_self_die if $@;
		262	};
		263	}
		264
		265	$port
184	}	266	}
185		267
		268	=item reg $portid, $name
		269
		270	Registers the given port under the name C<$name>. If the name already
		271	exists it is replaced.
		272
		273	A port can only be registered under one well known name.
		274
		275	A port automatically becomes unregistered when it is killed.
		276
		277	=cut
		278
		279	sub reg(@) {
		280	my ($portid, $name) = @_;
		281
		282	$REG{$name} = $portid;
		283	}
		284
186	=item rcv $portid, type => $callback->(@msg)	285	=item rcv $portid, $callback->(@msg)
187		286
		287	Replaces the callback on the specified miniport (or newly created port
		288	object, see C<port>). Full ports are configured with the following calls:
		289
		290	=item rcv $portid, tagstring => $callback->(@msg), ...
		291
188	=item rcv $portid, $smartmatch => $callback->(@msg)	292	=item rcv $portid, $smartmatch => $callback->(@msg), ...
189		293
190	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	294	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
191		295
192	Register a callback on the port identified by C<$portid>, which I<must> be	296	Register callbacks to be called on matching messages on the given full
193	a local port.	297	port (or newly created port).
194		298
195	The callback has to return a true value when its work is done, after	299	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	300	which is will be removed, or a false value in which case it will stay
197	registered.	301	registered.
198		302
		303	The global C<$SELF> (exported by this module) contains C<$portid> while
		304	executing the callback.
		305
		306	Runtime errors wdurign callback execution will result in the port being
		307	C<kil>ed.
		308
199	If the match is an array reference, then it will be matched against the	309	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	310	first elements of the message, otherwise only the first element is being
201	matched.	311	matched.
202		312
203	Any element in the match that is specified as C<_any_> (a function	313	Any element in the match that is specified as C<_any_> (a function
…		…
208	also the most efficient match (by far).	318	also the most efficient match (by far).
209		319
210	=cut	320	=cut
211		321
212	sub rcv($@) {	322	sub rcv($@) {
213	my ($port, $match, $cb) = @_;	323	my $portid = shift;
214
215	my $port = $PORT{$port}
216	or do {
217	my ($noderef, $lport) = split /#/, $port;	324	my ($noderef, $port) = split /#/, $port, 2;
218	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	325
		326	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
219	or Carp::croak "$port: can only rcv on local ports";	327	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
220		328
221	$PORT{$lport}	329	my $self = $PORT_DATA{$port}
222	or Carp::croak "$port: port does not exist";	330	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
223		331
224	$PORT{$port} = $PORT{$lport} # also return	332	"AnyEvent::MP::Port" eq ref $self
		333	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
		334
		335	while (@_) {
		336	my ($match, $cb) = splice @_, 0, 2;
		337
		338	if (!ref $match) {
		339	push @{ $self->{rc0}{$match} }, [$cb];
		340	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		341	my ($type, @match) = @$match;
		342	@match
		343	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		344	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
		345	} else {
		346	push @{ $self->{any} }, [$cb, $match];
		347	}
		348	}
		349
		350	$portid
		351	}
		352
		353	=item $closure = psub { BLOCK }
		354
		355	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
		356	closure is executed, sets up the environment in the same way as in C<rcv>
		357	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
		358
		359	This is useful when you register callbacks from C<rcv> callbacks:
		360
		361	rcv delayed_reply => sub {
		362	my ($delay, @reply) = @_;
		363	my $timer = AE::timer $delay, 0, psub {
		364	snd @reply, $SELF;
225	};	365	};
		366	};
226		367
227	if (!ref $match) {	368	=cut
228	push @{ $port->{rc0}{$match} }, [$cb];	369
229	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	370	sub psub(&) {
230	my ($type, @match) = @$match;	371	my $cb = shift;
231	@match	372
232	? push @{ $port->{rcv}{$match->[0]} }, [$cb, \@match]	373	my $port = $SELF
233	: push @{ $port->{rc0}{$match->[0]} }, [$cb];	374	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		375
		376	sub {
		377	local $SELF = $port;
		378
		379	if (wantarray) {
		380	my @res = eval { &$cb };
		381	_self_die if $@;
		382	@res
234	} else {	383	} else {
235	push @{ $port->{any} }, [$cb, $match];	384	my $res = eval { &$cb };
		385	_self_die if $@;
		386	$res
		387	}
236	}	388	}
237	}	389	}
238		390
239	sub _inject {	391	=item $guard = mon $portid, $cb->(@reason)
240	my ($port, $msg) = @{+shift};
241		392
242	$port = $PORT{$port}	393	=item $guard = mon $portid, $otherport
243	or return;
244		394
245	@_ = @$msg;	395	=item $guard = mon $portid, $otherport, @msg
246		396
247	for (@{ $port->{rc0}{$msg->[0]} }) {	397	Monitor the given port and do something when the port is killed.
248	$_ && &{$_->[0]}
249	&& undef $_;
250	}
251		398
252	for (@{ $port->{rcv}{$msg->[0]} }) {	399	In the first form, the callback is simply called with any number
253	$_ && [@_[1..$#{$_->[1]}]] ~~ $_->[1]	400	of C<@reason> elements (no @reason means that the port was deleted
254	&& &{$_->[0]}	401	"normally"). Note also that I<< the callback B<must> never die >>, so use
255	&& undef $_;	402	C<eval> if unsure.
256	}
257		403
258	for (@{ $port->{any} }) {	404	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
259	$_ && [@_[0..$#{$_->[1]}]] ~~ $_->[1]	405	a @reason was specified, i.e. on "normal" kils nothing happens, while
260	&& &{$_->[0]}	406	under all other conditions, the other port is killed with the same reason.
261	&& undef $_;
262	}
263	}
264		407
265	sub normalise_noderef($) {	408	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
266	my ($noderef) = @_;
267		409
268	my $cv = AE::cv;	410	Example: call a given callback when C<$port> is killed.
269	my @res;
270		411
271	$cv->begin (sub {	412	mon $port, sub { warn "port died because of <@_>\n" };
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		413
280	$noderef = $DEFAULT_PORT unless length $noderef;	414	Example: kill ourselves when C<$port> is killed abnormally.
281		415
282	my $idx;	416	mon $port, $self;
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		417
290	$cv->begin;	418	Example: send us a restart message another C<$port> is killed.
291	AnyEvent::Socket::resolve_sockaddr $nodename, $t \|\| "aemp=$DEFAULT_PORT", "tcp", 0, undef, sub {	419
		420	mon $port, $self => "restart";
		421
		422	=cut
		423
		424	sub mon {
		425	my ($noderef, $port) = split /#/, shift, 2;
		426
		427	my $node = $NODE{$noderef} \|\| add_node $noderef;
		428
		429	my $cb = shift;
		430
		431	unless (ref $cb) {
292	for (@_) {	432	if (@_) {
293	my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3];	433	# send a kill info message
294	push @res, [	434	my (@msg) = ($cb, @_);
295	$pri += 1e-5,	435	$cb = sub { snd @msg, @_ };
296	AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service
297	];
298	}
299	$cv->end;
300	};
301
302	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;
303	#
304	# for (@ipv4) {
305	# push @res, [
306	# $pri,
307	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,
308	# ];
309	# }
310	} else {	436	} else {
311	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	437	# simply kill other port
312	or Carp::croak "$t: unparsable transport descriptor";	438	my $port = $cb;
313		439	$cb = sub { kil $port, @_ if @_ };
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	}
325	}	440	}
326	}	441	}
327		442
328	$cv->end;	443	$node->monitor ($port, $cb);
329		444
330	$cv	445	defined wantarray
		446	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
331	}	447	}
332		448
333	sub become_public {	449	=item $guard = mon_guard $port, $ref, $ref...
334	return if $PUBLIC;
335		450
336	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	451	Monitors the given C<$port> and keeps the passed references. When the port
337	my @args = @_;	452	is killed, the references will be freed.
338		453
339	$NODE = (normalise_noderef $noderef)->recv;	454	Optionally returns a guard that will stop the monitoring.
340		455
341	for my $t (split /,/, $NODE) {	456	This function is useful when you create e.g. timers or other watchers and
342	$NODE{$t} = $NODE{""};	457	want to free them when the port gets killed:
343		458
344	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	459	$port->rcv (start => sub {
345		460	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
346	$LISTENER{$t} = AnyEvent::MP::Transport::mp_server $host, $port,	461	undef $timer if 0.9 < rand;
347	@args,
348	on_error => sub {
349	die "on_error<@_>\n";#d#
350	},
351	on_connect => sub {
352	my ($tp) = @_;
353
354	$NODE{$tp->{remote_id}} = $_[0];
355	},
356	sub {
357	my ($tp) = @_;
358
359	$NODE{"$tp->{peerhost}:$tp->{peerport}"} = $tp;
360	},
361	;	462	});
362	}	463	});
363		464
364	$PUBLIC = 1;	465	=cut
		466
		467	sub mon_guard {
		468	my ($port, @refs) = @_;
		469
		470	mon $port, sub { 0 && @refs }
365	}	471	}
366		472
		473	=item lnk $port1, $port2
		474
		475	Link two ports. This is simply a shorthand for:
		476
		477	mon $port1, $port2;
		478	mon $port2, $port1;
		479
		480	It means that if either one is killed abnormally, the other one gets
		481	killed as well.
		482
		483	=item kil $portid[, @reason]
		484
		485	Kill the specified port with the given C<@reason>.
		486
		487	If no C<@reason> is specified, then the port is killed "normally" (linked
		488	ports will not be kileld, or even notified).
		489
		490	Otherwise, linked ports get killed with the same reason (second form of
		491	C<mon>, see below).
		492
		493	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		494	will be reported as reason C<< die => $@ >>.
		495
		496	Transport/communication errors are reported as C<< transport_error =>
		497	$message >>.
		498
367	=back	499	=back
368		500
		501	=head1 FUNCTIONS FOR NODES
		502
		503	=over 4
		504
		505	=item become_public $noderef
		506
		507	Tells the node to become a public node, i.e. reachable from other nodes.
		508
		509	The first argument is the (unresolved) node reference of the local node
		510	(if missing then the empty string is used).
		511
		512	It is quite common to not specify anything, in which case the local node
		513	tries to listen on the default port, or to only specify a port number, in
		514	which case AnyEvent::MP tries to guess the local addresses.
		515
		516	=cut
		517
		518	=back
		519
369	=head1 NODE MESSAGES	520	=head1 NODE MESSAGES
370		521
371	Nodes understand the following messages sent to them:	522	Nodes understand the following messages sent to them. Many of them take
		523	arguments called C<@reply>, which will simply be used to compose a reply
		524	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
		525	the remaining arguments are simply the message data.
		526
		527	While other messages exist, they are not public and subject to change.
372		528
373	=over 4	529	=over 4
374		530
375	=cut	531	=cut
376		532
377	#############################################################################	533	=item lookup => $name, @reply
378	# self node code
379		534
380	sub _new_port($) {	535	Replies with the port ID of the specified well-known port, or C<undef>.
381	my ($name) = @_;
382		536
383	my ($noderef, $portname) = split /#/, $name;	537	=item devnull => ...
384		538
385	$PORT{$name} =	539	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		540
394	=item relay => $port, @msg	541	=item relay => $port, @msg
395		542
396	Simply forwards the message to the given port.	543	Simply forwards the message to the given port.
397		544
398	=cut
399
400	rcv "", relay => \&snd;
401
402	=item eval => $string[ @reply]	545	=item eval => $string[ @reply]
403		546
404	Evaluates the given string. If C<@reply> is given, then a message of the	547	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).	548	form C<@reply, $@, @evalres> is sent.
406		549
407	=cut	550	Example: crash another node.
408		551
409	rcv "", eval => sub {	552	snd $othernode, eval => "exit";
410	my (undef, $string, @reply) = @_;
411	my @res = eval $string;
412	snd @reply, "$@", @res if @reply;
413	};
414		553
415	=item time => @reply	554	=item time => @reply
416		555
417	Replies the the current node time to C<@reply>.	556	Replies the the current node time to C<@reply>.
418		557
419	=cut	558	Example: tell the current node to send the current time to C<$myport> in a
		559	C<timereply> message.
420		560
421	rcv "", time => sub { shift; snd @_, AE::time };	561	snd $NODE, time => $myport, timereply => 1, 2;
		562	# => snd $myport, timereply => 1, 2, <time>
		563
		564	=back
		565
		566	=head1 AnyEvent::MP vs. Distributed Erlang
		567
		568	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node
		569	== aemp node, erlang process == aemp port), so many of the documents and
		570	programming techniques employed by erlang apply to AnyEvent::MP. Here is a
		571	sample:
		572
		573	http://www.erlang.se/doc/programming_rules.shtml
		574	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		575	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
		576	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		577
		578	Despite the similarities, there are also some important differences:
		579
		580	=over 4
		581
		582	=item * Node references contain the recipe on how to contact them.
		583
		584	Erlang relies on special naming and DNS to work everywhere in the
		585	same way. AEMP relies on each node knowing it's own address(es), with
		586	convenience functionality.
		587
		588	This means that AEMP requires a less tightly controlled environment at the
		589	cost of longer node references and a slightly higher management overhead.
		590
		591	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		592
		593	Erlang uses processes that selctively receive messages, and therefore
		594	needs a queue. AEMP is event based, queuing messages would serve no useful
		595	purpose.
		596
		597	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		598
		599	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		600
		601	Sending messages in erlang is synchronous and blocks the process. AEMP
		602	sends are immediate, connection establishment is handled in the
		603	background.
		604
		605	=item * Erlang can silently lose messages, AEMP cannot.
		606
		607	Erlang makes few guarantees on messages delivery - messages can get lost
		608	without any of the processes realising it (i.e. you send messages a, b,
		609	and c, and the other side only receives messages a and c).
		610
		611	AEMP guarantees correct ordering, and the guarantee that there are no
		612	holes in the message sequence.
		613
		614	=item * In erlang, processes can be declared dead and later be found to be
		615	alive.
		616
		617	In erlang it can happen that a monitored process is declared dead and
		618	linked processes get killed, but later it turns out that the process is
		619	still alive - and can receive messages.
		620
		621	In AEMP, when port monitoring detects a port as dead, then that port will
		622	eventually be killed - it cannot happen that a node detects a port as dead
		623	and then later sends messages to it, finding it is still alive.
		624
		625	=item * Erlang can send messages to the wrong port, AEMP does not.
		626
		627	In erlang it is quite possible that a node that restarts reuses a process
		628	ID known to other nodes for a completely different process, causing
		629	messages destined for that process to end up in an unrelated process.
		630
		631	AEMP never reuses port IDs, so old messages or old port IDs floating
		632	around in the network will not be sent to an unrelated port.
		633
		634	=item * Erlang uses unprotected connections, AEMP uses secure
		635	authentication and can use TLS.
		636
		637	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		638	securely authenticate nodes.
		639
		640	=item * The AEMP protocol is optimised for both text-based and binary
		641	communications.
		642
		643	The AEMP protocol, unlike the erlang protocol, supports both
		644	language-independent text-only protocols (good for debugging) and binary,
		645	language-specific serialisers (e.g. Storable).
		646
		647	It has also been carefully designed to be implementable in other languages
		648	with a minimum of work while gracefully degrading fucntionality to make the
		649	protocol simple.
422		650
423	=back	651	=back
424		652
425	=head1 SEE ALSO	653	=head1 SEE ALSO
426		654

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Revision 1.4 by root, Sat Aug 1 07:36:30 2009 UTC vs.
Revision 1.32 by root, Wed Aug 5 19:58:46 2009 UTC