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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.6 by root, Sat Aug 1 10:02:33 2009 UTC vs.
Revision 1.37 by root, Fri Aug 7 16:47:23 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 };
…		…
20		23
21	# more, smarter, matches (_any_ is exported by this module)	24	# more, smarter, matches (_any_ is exported by this module)
22	rcv $port, [child_died => $pid] => sub { ...	25	rcv $port, [child_died => $pid] => sub { ...
23	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
24		27
		28	# monitoring
		29	mon $port, $cb->(@msg) # callback is invoked on death
		30	mon $port, $otherport # kill otherport on abnormal death
		31	mon $port, $otherport, @msg # send message on death
		32
25	=head1 DESCRIPTION	33	=head1 DESCRIPTION
26		34
27	This module (-family) implements a simple message passing framework.	35	This module (-family) implements a simple message passing framework.
28		36
29	Despite its simplicity, you can securely message other processes running	37	Despite its simplicity, you can securely message other processes running
30	on the same or other hosts.	38	on the same or other hosts.
31		39
		40	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		41	manual page.
		42
32	At the moment, this module family is severly brokena nd underdocumented,	43	At the moment, this module family is severly broken and underdocumented,
33	so do not use. This was uploaded mainly to resreve the CPAN namespace -	44	so do not use. This was uploaded mainly to reserve the CPAN namespace -
34	stay tuned!	45	stay tuned! The basic API should be finished, however.
35		46
36	=head1 CONCEPTS	47	=head1 CONCEPTS
37		48
38	=over 4	49	=over 4
39		50
40	=item port	51	=item port
41		52
42	A port is something you can send messages to with the C<snd> function, and	53	A port is something you can send messages to (with the C<snd> function).
43	you can register C<rcv> handlers with. All C<rcv> handlers will receive	54
44	messages they match, messages will not be queued.	55	Some ports allow you to register C<rcv> handlers that can match specific
		56	messages. All C<rcv> handlers will receive messages they match, messages
		57	will not be queued.
45		58
46	=item port id - C<noderef#portname>	59	=item port id - C<noderef#portname>
47		60
48	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	61	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as
49	by a port name (a printable string of unspecified format).	62	separator, and a port name (a printable string of unspecified format). An
		63	exception is the the node port, whose ID is identical to its node
		64	reference.
50		65
51	=item node	66	=item node
52		67
53	A node is a single process containing at least one port - the node	68	A node is a single process containing at least one port - the node
54	port. You can send messages to node ports to let them create new ports,	69	port. You can send messages to node ports to find existing ports or to
55	among other things.	70	create new ports, among other things.
56		71
57	Initially, nodes are either private (single-process only) or hidden	72	Nodes are either private (single-process only), slaves (connected to a
58	(connected to a master node only). Only when they epxlicitly "become	73	master node only) or public nodes (connectable from unrelated nodes).
59	public" can you send them messages from unrelated other nodes.
60		74
61	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	75	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
62		76
63	A noderef is a string that either uniquely identifies a given node (for	77	A node reference is a string that either simply identifies the node (for
64	private and hidden nodes), or contains a recipe on how to reach a given	78	private and slave nodes), or contains a recipe on how to reach a given
65	node (for public nodes).	79	node (for public nodes).
66		80
		81	This recipe is simply a comma-separated list of C<address:port> pairs (for
		82	TCP/IP, other protocols might look different).
		83
		84	Node references come in two flavours: resolved (containing only numerical
		85	addresses) or unresolved (where hostnames are used instead of addresses).
		86
		87	Before using an unresolved node reference in a message you first have to
		88	resolve it.
		89
67	=back	90	=back
68		91
69	=head1 VARIABLES/FUNCTIONS	92	=head1 VARIABLES/FUNCTIONS
70		93
71	=over 4	94	=over 4
72		95
73	=cut	96	=cut
74		97
75	package AnyEvent::MP;	98	package AnyEvent::MP;
76		99
77	use AnyEvent::MP::Util ();
78	use AnyEvent::MP::Node;	100	use AnyEvent::MP::Base;
79	use AnyEvent::MP::Transport;
80		101
81	use utf8;
82	use common::sense;	102	use common::sense;
83		103
84	use Carp ();	104	use Carp ();
85		105
86	use AE ();	106	use AE ();
87		107
88	use base "Exporter";	108	use base "Exporter";
89		109
90	our $VERSION = '0.01';	110	our $VERSION = '0.1';
91	our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_);	111	our @EXPORT = qw(
		112	NODE $NODE *SELF node_of _any_
		113	resolve_node initialise_node
		114	snd rcv mon kil reg psub
		115	port
		116	);
92		117
93	our $DEFAULT_SECRET;	118	our $SELF;
94	our $DEFAULT_PORT = "4040";
95		119
96	our $CONNECT_INTERVAL = 5; # new connect every 5s, at least	120	sub _self_die() {
97	our $CONNECT_TIMEOUT = 30; # includes handshake	121	my $msg = $@;
98		122	$msg =~ s/\n+$// unless ref $msg;
99	sub default_secret {	123	kil $SELF, die => $msg;
100	unless (defined $DEFAULT_SECRET) {
101	if (open my $fh, "<$ENV{HOME}/.aemp-secret") {
102	sysread $fh, $DEFAULT_SECRET, -s $fh;
103	} else {
104	$DEFAULT_SECRET = AnyEvent::MP::Util::nonce 32;
105	}
106	}
107
108	$DEFAULT_SECRET
109	}	124	}
110		125
111	=item NODE / $NODE	126	=item $thisnode = NODE / $NODE
112		127
113	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	128	The C<NODE> function returns, and the C<$NODE> variable contains
114	the local node. The value is initialised by a call to C<become_public> or	129	the noderef of the local node. The value is initialised by a call
115	C<become_slave>, after which all local port identifiers become invalid.	130	to C<become_public> or C<become_slave>, after which all local port
		131	identifiers become invalid.
116		132
117	=cut	133	=item $noderef = node_of $port
118		134
119	our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie	135	Extracts and returns the noderef from a portid or a noderef.
120	our $ID = "a0";
121	our $PUBLIC = 0;
122	our $NODE;
123	our $PORT;
124		136
125	our %NODE; # node id to transport mapping, or "undef", for local node	137	=item initialise_node $noderef, $seednode, $seednode...
126	our %PORT; # local ports
127	our %LISTENER; # local transports
128		138
129	sub NODE() { $NODE }	139	=item initialise_node "slave/", $master, $master...
130		140
131	{	141	Before a node can talk to other nodes on the network it has to initialise
132	use POSIX ();	142	itself - the minimum a node needs to know is it's own name, and optionally
133	my $nodename = (POSIX::uname)[1];	143	it should know the noderefs of some other nodes in the network.
134	$NODE = "$$\@$nodename";
135	}
136		144
137	sub _ANY_() { 1 }	145	This function initialises a node - it must be called exactly once (or
138	sub _any_() { \&_ANY_ }	146	never) before calling other AnyEvent::MP functions.
139		147
140	sub add_node {	148	All arguments are noderefs, which can be either resolved or unresolved.
141	my ($noderef) = @_;
142		149
143	return $NODE{$noderef}	150	There are two types of networked nodes, public nodes and slave nodes:
144	if exists $NODE{$noderef};
145		151
146	for (split /,/, $noderef) {	152	=over 4
147	return $NODE{$noderef} = $NODE{$_}
148	if exists $NODE{$_};
149	}
150		153
151	# for indirect sends, use a different class	154	=item public nodes
152	my $node = new AnyEvent::MP::Node::Direct $noderef;
153		155
154	$NODE{$_} = $node	156	For public nodes, C<$noderef> must either be a (possibly unresolved)
155	for $noderef, split /,/, $noderef;	157	noderef, in which case it will be resolved, or C<undef> (or missing), in
		158	which case the noderef will be guessed.
156		159
157	$node	160	Afterwards, the node will bind itself on all endpoints and try to connect
158	}	161	to all additional C<$seednodes> that are specified. Seednodes are optional
		162	and can be used to quickly bootstrap the node into an existing network.
159		163
		164	=item slave nodes
		165
		166	When the C<$noderef> is the special string C<slave/>, then the node will
		167	become a slave node. Slave nodes cannot be contacted from outside and will
		168	route most of their traffic to the master node that they attach to.
		169
		170	At least one additional noderef is required: The node will try to connect
		171	to all of them and will become a slave attached to the first node it can
		172	successfully connect to.
		173
		174	=back
		175
		176	This function will block until all nodes have been resolved and, for slave
		177	nodes, until it has successfully established a connection to a master
		178	server.
		179
		180	Example: become a public node listening on the default node.
		181
		182	initialise_node;
		183
		184	Example: become a public node, and try to contact some well-known master
		185	servers to become part of the network.
		186
		187	initialise_node undef, "master1", "master2";
		188
		189	Example: become a public node listening on port C<4041>.
		190
		191	initialise_node 4041;
		192
		193	Example: become a public node, only visible on localhost port 4044.
		194
		195	initialise_node "locahost:4044";
		196
		197	Example: become a slave node to any of the specified master servers.
		198
		199	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		200
		201	=item $cv = resolve_node $noderef
		202
		203	Takes an unresolved node reference that may contain hostnames and
		204	abbreviated IDs, resolves all of them and returns a resolved node
		205	reference.
		206
		207	In addition to C<address:port> pairs allowed in resolved noderefs, the
		208	following forms are supported:
		209
		210	=over 4
		211
		212	=item the empty string
		213
		214	An empty-string component gets resolved as if the default port (4040) was
		215	specified.
		216
		217	=item naked port numbers (e.g. C<1234>)
		218
		219	These are resolved by prepending the local nodename and a colon, to be
		220	further resolved.
		221
		222	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		223
		224	These are resolved by using AnyEvent::DNS to resolve them, optionally
		225	looking up SRV records for the C<aemp=4040> port, if no port was
		226	specified.
		227
		228	=back
		229
		230	=item $SELF
		231
		232	Contains the current port id while executing C<rcv> callbacks or C<psub>
		233	blocks.
		234
		235	=item SELF, %SELF, @SELF...
		236
		237	Due to some quirks in how perl exports variables, it is impossible to
		238	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		239	module, but only C<$SELF> is currently used.
		240
160	=item snd $portid, type => @data	241	=item snd $port, type => @data
161		242
162	=item snd $portid, @msg	243	=item snd $port, @msg
163		244
164	Send the given message to the given port ID, which can identify either a	245	Send the given message to the given port ID, which can identify either
165	local or a remote port.	246	a local or a remote port, and can be either a string or soemthignt hat
		247	stringifies a sa port ID (such as a port object :).
166		248
167	While the message can be about anything, it is highly recommended to use	249	While the message can be about anything, it is highly recommended to use a
168	a constant string as first element.	250	string as first element (a portid, or some word that indicates a request
		251	type etc.).
169		252
170	The message data effectively becomes read-only after a call to this	253	The message data effectively becomes read-only after a call to this
171	function: modifying any argument is not allowed and can cause many	254	function: modifying any argument is not allowed and can cause many
172	problems.	255	problems.
173		256
…		…
175	JSON is used, then only strings, numbers and arrays and hashes consisting	258	JSON is used, then only strings, numbers and arrays and hashes consisting
176	of those are allowed (no objects). When Storable is used, then anything	259	of those are allowed (no objects). When Storable is used, then anything
177	that Storable can serialise and deserialise is allowed, and for the local	260	that Storable can serialise and deserialise is allowed, and for the local
178	node, anything can be passed.	261	node, anything can be passed.
179		262
180	=cut	263	=item $local_port = port
181		264
182	sub snd(@) {	265	Create a new local port object that can be used either as a pattern
183	my ($noderef, $port) = split /#/, shift, 2;	266	matching port ("full port") or a single-callback port ("miniport"),
		267	depending on how C<rcv> callbacks are bound to the object.
184		268
185	add_node $noderef	269	=item $port = port { my @msg = @_; $finished }
186	unless exists $NODE{$noderef};
187		270
188	$NODE{$noderef}->send (["$port", [@_]]);	271	Creates a "miniport", that is, a very lightweight port without any pattern
		272	matching behind it, and returns its ID. Semantically the same as creating
		273	a port and calling C<rcv $port, $callback> on it.
		274
		275	The block will be called for every message received on the port. When the
		276	callback returns a true value its job is considered "done" and the port
		277	will be destroyed. Otherwise it will stay alive.
		278
		279	The message will be passed as-is, no extra argument (i.e. no port id) will
		280	be passed to the callback.
		281
		282	If you need the local port id in the callback, this works nicely:
		283
		284	my $port; $port = port {
		285	snd $otherport, reply => $port;
		286	};
		287
		288	=cut
		289
		290	sub rcv($@);
		291
		292	sub port(;&) {
		293	my $id = "$UNIQ." . $ID++;
		294	my $port = "$NODE#$id";
		295
		296	if (@_) {
		297	rcv $port, shift;
		298	} else {
		299	$PORT{$id} = sub { }; # nop
		300	}
		301
		302	$port
189	}	303	}
190		304
		305	=item reg $port, $name
		306
		307	=item reg $name
		308
		309	Registers the given port (or C<$SELF><<< if missing) under the name
		310	C<$name>. If the name already exists it is replaced.
		311
		312	A port can only be registered under one well known name.
		313
		314	A port automatically becomes unregistered when it is killed.
		315
		316	=cut
		317
		318	sub reg(@) {
		319	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		320
		321	$REG{$_[0]} = $port;
		322	}
		323
191	=item rcv $portid, type => $callback->(@msg)	324	=item rcv $port, $callback->(@msg)
192		325
		326	Replaces the callback on the specified miniport (after converting it to
		327	one if required).
		328
		329	=item rcv $port, tagstring => $callback->(@msg), ...
		330
193	=item rcv $portid, $smartmatch => $callback->(@msg)	331	=item rcv $port, $smartmatch => $callback->(@msg), ...
194		332
195	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	333	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
196		334
197	Register a callback on the port identified by C<$portid>, which I<must> be	335	Register callbacks to be called on matching messages on the given full
198	a local port.	336	port (after converting it to one if required) and return the port.
199		337
200	The callback has to return a true value when its work is done, after	338	The callback has to return a true value when its work is done, after
201	which is will be removed, or a false value in which case it will stay	339	which is will be removed, or a false value in which case it will stay
202	registered.	340	registered.
203		341
		342	The global C<$SELF> (exported by this module) contains C<$port> while
		343	executing the callback.
		344
		345	Runtime errors wdurign callback execution will result in the port being
		346	C<kil>ed.
		347
204	If the match is an array reference, then it will be matched against the	348	If the match is an array reference, then it will be matched against the
205	first elements of the message, otherwise only the first element is being	349	first elements of the message, otherwise only the first element is being
206	matched.	350	matched.
207		351
208	Any element in the match that is specified as C<_any_> (a function	352	Any element in the match that is specified as C<_any_> (a function
…		…
210		354
211	While not required, it is highly recommended that the first matching	355	While not required, it is highly recommended that the first matching
212	element is a string identifying the message. The one-string-only match is	356	element is a string identifying the message. The one-string-only match is
213	also the most efficient match (by far).	357	also the most efficient match (by far).
214		358
		359	Example: create a port and bind receivers on it in one go.
		360
		361	my $port = rcv port,
		362	msg1 => sub { ...; 0 },
		363	msg2 => sub { ...; 0 },
		364	;
		365
		366	Example: create a port, bind receivers and send it in a message elsewhere
		367	in one go:
		368
		369	snd $otherport, reply =>
		370	rcv port,
		371	msg1 => sub { ...; 0 },
		372	...
		373	;
		374
215	=cut	375	=cut
216		376
217	sub rcv($@) {	377	sub rcv($@) {
218	my ($port, $match, $cb) = @_;	378	my $port = shift;
219
220	my $port = $PORT{$port}
221	or do {
222	my ($noderef, $lport) = split /#/, $port;	379	my ($noderef, $portid) = split /#/, $port, 2;
223	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	380
		381	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
224	or Carp::croak "$port: can only rcv on local ports";	382	or Carp::croak "$port: rcv can only be called on local ports, caught";
225		383
226	$PORT{$lport}	384	if (@_ == 1) {
227	or Carp::croak "$port: port does not exist";	385	my $cb = shift;
		386	delete $PORT_DATA{$portid};
		387	$PORT{$portid} = sub {
		388	local $SELF = $port;
		389	eval {
228		390	&$cb
229	$PORT{$port} = $PORT{$lport} # also return	391	and kil $port;
		392	};
		393	_self_die if $@;
230	};	394	};
231
232	if (!ref $match) {
233	push @{ $port->{rc0}{$match} }, [$cb];
234	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
235	my ($type, @match) = @$match;
236	@match
237	? push @{ $port->{rcv}{$match->[0]} }, [$cb, \@match]
238	: push @{ $port->{rc0}{$match->[0]} }, [$cb];
239	} else {	395	} else {
240	push @{ $port->{any} }, [$cb, $match];	396	my $self = $PORT_DATA{$portid} \|\|= do {
241	}	397	my $self = bless {
242	}	398	id => $port,
		399	}, "AnyEvent::MP::Port";
243		400
244	sub _inject {	401	$PORT{$portid} = sub {
245	my ($port, $msg) = @{+shift};	402	local $SELF = $port;
246		403
247	$port = $PORT{$port}	404	eval {
248	or return;	405	for (@{ $self->{rc0}{$_[0]} }) {
249
250	@_ = @$msg;
251
252	for (@{ $port->{rc0}{$msg->[0]} }) {
253	$_ && &{$_->[0]}	406	$_ && &{$_->[0]}
254	&& undef $_;	407	&& undef $_;
255	}
256
257	for (@{ $port->{rcv}{$msg->[0]} }) {
258	$_ && [@_[1..$#{$_->[1]}]] ~~ $_->[1]
259	&& &{$_->[0]}
260	&& undef $_;
261	}
262
263	for (@{ $port->{any} }) {
264	$_ && [@_[0..$#{$_->[1]}]] ~~ $_->[1]
265	&& &{$_->[0]}
266	&& undef $_;
267	}
268	}
269
270	sub normalise_noderef($) {
271	my ($noderef) = @_;
272
273	my $cv = AE::cv;
274	my @res;
275
276	$cv->begin (sub {
277	my %seen;
278	my @refs;
279	for (sort { $a->[0] <=> $b->[0] } @res) {
280	push @refs, $_->[1] unless $seen{$_->[1]}++
281	}
282	shift->send (join ",", @refs);
283	});
284
285	$noderef = $DEFAULT_PORT unless length $noderef;
286
287	my $idx;
288	for my $t (split /,/, $noderef) {
289	my $pri = ++$idx;
290
291	#TODO: this should be outside normalise_noderef and in become_public
292	if ($t =~ /^\d*$/) {
293	my $nodename = (POSIX::uname)[1];
294
295	$cv->begin;
296	AnyEvent::Socket::resolve_sockaddr $nodename, $t \|\| "aemp=$DEFAULT_PORT", "tcp", 0, undef, sub {
297	for (@_) {
298	my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3];
299	push @res, [
300	$pri += 1e-5,
301	AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service
302	];	408	}
		409
		410	for (@{ $self->{rcv}{$_[0]} }) {
		411	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		412	&& &{$_->[0]}
		413	&& undef $_;
		414	}
		415
		416	for (@{ $self->{any} }) {
		417	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		418	&& &{$_->[0]}
		419	&& undef $_;
		420	}
303	}	421	};
304	$cv->end;	422	_self_die if $@;
305	};	423	};
306		424
307	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;	425	$self
308	#	426	};
309	# for (@ipv4) {	427
310	# push @res, [	428	"AnyEvent::MP::Port" eq ref $self
311	# $pri,	429	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
312	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,	430
313	# ];	431	while (@_) {
314	# }	432	my ($match, $cb) = splice @_, 0, 2;
		433
		434	if (!ref $match) {
		435	push @{ $self->{rc0}{$match} }, [$cb];
		436	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		437	my ($type, @match) = @$match;
		438	@match
		439	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		440	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
315	} else {	441	} else {
316	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	442	push @{ $self->{any} }, [$cb, $match];
317	or Carp::croak "$t: unparsable transport descriptor";
318
319	$cv->begin;
320	AnyEvent::Socket::resolve_sockaddr $host, $port, "tcp", 0, undef, sub {
321	for (@_) {
322	my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3];
323	push @res, [
324	$pri += 1e-5,
325	AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service
326	];
327	}
328	$cv->end;
329	}	443	}
330	}	444	}
331	}	445	}
332		446
333	$cv->end;	447	$port
334
335	$cv
336	}	448	}
337		449
338	sub become_public {	450	=item $closure = psub { BLOCK }
339	return if $PUBLIC;
340		451
341	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	452	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
342	my @args = @_;	453	closure is executed, sets up the environment in the same way as in C<rcv>
		454	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
343		455
344	$NODE = (normalise_noderef $noderef)->recv;	456	This is useful when you register callbacks from C<rcv> callbacks:
345		457
346	for my $t (split /,/, $NODE) {	458	rcv delayed_reply => sub {
347	$NODE{$t} = $NODE{""};	459	my ($delay, @reply) = @_;
348		460	my $timer = AE::timer $delay, 0, psub {
349	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	461	snd @reply, $SELF;
350
351	$LISTENER{$t} = AnyEvent::MP::Transport::mp_server $host, $port,
352	@args,
353	on_error => sub {
354	die "on_error<@_>\n";#d#
355	},
356	on_connect => sub {
357	my ($tp) = @_;
358
359	$NODE{$tp->{remote_id}} = $_[0];
360	},
361	sub {
362	my ($tp) = @_;
363
364	$NODE{"$tp->{peerhost}:$tp->{peerport}"} = $tp;
365	},
366	;	462	};
		463	};
		464
		465	=cut
		466
		467	sub psub(&) {
		468	my $cb = shift;
		469
		470	my $port = $SELF
		471	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		472
		473	sub {
		474	local $SELF = $port;
		475
		476	if (wantarray) {
		477	my @res = eval { &$cb };
		478	_self_die if $@;
		479	@res
		480	} else {
		481	my $res = eval { &$cb };
		482	_self_die if $@;
		483	$res
		484	}
367	}	485	}
368
369	$PUBLIC = 1;
370	}	486	}
		487
		488	=item $guard = mon $port, $cb->(@reason)
		489
		490	=item $guard = mon $port, $rcvport
		491
		492	=item $guard = mon $port
		493
		494	=item $guard = mon $port, $rcvport, @msg
		495
		496	Monitor the given port and do something when the port is killed, and
		497	optionally return a guard that can be used to stop monitoring again.
		498
		499	In the first form (callback), the callback is simply called with any
		500	number of C<@reason> elements (no @reason means that the port was deleted
		501	"normally"). Note also that I<< the callback B<must> never die >>, so use
		502	C<eval> if unsure.
		503
		504	In the second form (another port given), the other port (C<$rcvport)
		505	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
		506	"normal" kils nothing happens, while under all other conditions, the other
		507	port is killed with the same reason.
		508
		509	The third form (kill self) is the same as the second form, except that
		510	C<$rvport> defaults to C<$SELF>.
		511
		512	In the last form (message), a message of the form C<@msg, @reason> will be
		513	C<snd>.
		514
		515	As a rule of thumb, monitoring requests should always monitor a port from
		516	a local port (or callback). The reason is that kill messages might get
		517	lost, just like any other message. Another less obvious reason is that
		518	even monitoring requests can get lost (for exmaple, when the connection
		519	to the other node goes down permanently). When monitoring a port locally
		520	these problems do not exist.
		521
		522	Example: call a given callback when C<$port> is killed.
		523
		524	mon $port, sub { warn "port died because of <@_>\n" };
		525
		526	Example: kill ourselves when C<$port> is killed abnormally.
		527
		528	mon $port;
		529
		530	Example: send us a restart message when another C<$port> is killed.
		531
		532	mon $port, $self => "restart";
		533
		534	=cut
		535
		536	sub mon {
		537	my ($noderef, $port) = split /#/, shift, 2;
		538
		539	my $node = $NODE{$noderef} \|\| add_node $noderef;
		540
		541	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
		542
		543	unless (ref $cb) {
		544	if (@_) {
		545	# send a kill info message
		546	my (@msg) = @_;
		547	$cb = sub { snd @msg, @_ };
		548	} else {
		549	# simply kill other port
		550	my $port = $cb;
		551	$cb = sub { kil $port, @_ if @_ };
		552	}
		553	}
		554
		555	$node->monitor ($port, $cb);
		556
		557	defined wantarray
		558	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		559	}
		560
		561	=item $guard = mon_guard $port, $ref, $ref...
		562
		563	Monitors the given C<$port> and keeps the passed references. When the port
		564	is killed, the references will be freed.
		565
		566	Optionally returns a guard that will stop the monitoring.
		567
		568	This function is useful when you create e.g. timers or other watchers and
		569	want to free them when the port gets killed:
		570
		571	$port->rcv (start => sub {
		572	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		573	undef $timer if 0.9 < rand;
		574	});
		575	});
		576
		577	=cut
		578
		579	sub mon_guard {
		580	my ($port, @refs) = @_;
		581
		582	#TODO: mon-less form?
		583
		584	mon $port, sub { 0 && @refs }
		585	}
		586
		587	=item kil $port[, @reason]
		588
		589	Kill the specified port with the given C<@reason>.
		590
		591	If no C<@reason> is specified, then the port is killed "normally" (linked
		592	ports will not be kileld, or even notified).
		593
		594	Otherwise, linked ports get killed with the same reason (second form of
		595	C<mon>, see below).
		596
		597	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		598	will be reported as reason C<< die => $@ >>.
		599
		600	Transport/communication errors are reported as C<< transport_error =>
		601	$message >>.
371		602
372	=back	603	=back
373		604
374	=head1 NODE MESSAGES	605	=head1 NODE MESSAGES
375		606
376	Nodes understand the following messages sent to them. Many of them take	607	Nodes understand the following messages sent to them. Many of them take
377	arguments called C<@reply>, which will simply be used to compose a reply	608	arguments called C<@reply>, which will simply be used to compose a reply
378	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	609	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
379	the remaining arguments are simply the message data.	610	the remaining arguments are simply the message data.
380		611
		612	While other messages exist, they are not public and subject to change.
		613
381	=over 4	614	=over 4
382		615
383	=cut	616	=cut
384		617
385	#############################################################################	618	=item lookup => $name, @reply
386	# self node code
387		619
388	sub _new_port($) {	620	Replies with the port ID of the specified well-known port, or C<undef>.
389	my ($name) = @_;
390		621
391	my ($noderef, $portname) = split /#/, $name;	622	=item devnull => ...
392		623
393	$PORT{$name} =	624	Generic data sink/CPU heat conversion.
394	$PORT{$portname} = {
395	names => [$name, $portname],
396	};
397	}
398
399	$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE;
400	_new_port "";
401		625
402	=item relay => $port, @msg	626	=item relay => $port, @msg
403		627
404	Simply forwards the message to the given port.	628	Simply forwards the message to the given port.
405
406	=cut
407
408	rcv "", relay => \&snd;
409		629
410	=item eval => $string[ @reply]	630	=item eval => $string[ @reply]
411		631
412	Evaluates the given string. If C<@reply> is given, then a message of the	632	Evaluates the given string. If C<@reply> is given, then a message of the
413	form C<@reply, $@, @evalres> is sent.	633	form C<@reply, $@, @evalres> is sent.
414		634
415	Example: crash another node.	635	Example: crash another node.
416		636
417	snd $othernode, eval => "exit";	637	snd $othernode, eval => "exit";
418		638
419	=cut
420
421	rcv "", eval => sub {
422	my (undef, $string, @reply) = @_;
423	my @res = eval $string;
424	snd @reply, "$@", @res if @reply;
425	};
426
427	=item time => @reply	639	=item time => @reply
428		640
429	Replies the the current node time to C<@reply>.	641	Replies the the current node time to C<@reply>.
430		642
431	Example: tell the current node to send the current time to C<$myport> in a	643	Example: tell the current node to send the current time to C<$myport> in a
432	C<timereply> message.	644	C<timereply> message.
433		645
434	snd $NODE, time => $myport, timereply => 1, 2;	646	snd $NODE, time => $myport, timereply => 1, 2;
435	# => snd $myport, timereply => 1, 2, <time>	647	# => snd $myport, timereply => 1, 2, <time>
436		648
437	=cut	649	=back
438		650
439	rcv "", time => sub { shift; snd @_, AE::time };	651	=head1 AnyEvent::MP vs. Distributed Erlang
		652
		653	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
		654	== aemp node, Erlang process == aemp port), so many of the documents and
		655	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		656	sample:
		657
		658	http://www.Erlang.se/doc/programming_rules.shtml
		659	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		660	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		661	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		662
		663	Despite the similarities, there are also some important differences:
		664
		665	=over 4
		666
		667	=item * Node references contain the recipe on how to contact them.
		668
		669	Erlang relies on special naming and DNS to work everywhere in the
		670	same way. AEMP relies on each node knowing it's own address(es), with
		671	convenience functionality.
		672
		673	This means that AEMP requires a less tightly controlled environment at the
		674	cost of longer node references and a slightly higher management overhead.
		675
		676	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		677
		678	Erlang uses processes that selctively receive messages, and therefore
		679	needs a queue. AEMP is event based, queuing messages would serve no useful
		680	purpose.
		681
		682	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
		683
		684	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		685
		686	Sending messages in Erlang is synchronous and blocks the process. AEMP
		687	sends are immediate, connection establishment is handled in the
		688	background.
		689
		690	=item * Erlang can silently lose messages, AEMP cannot.
		691
		692	Erlang makes few guarantees on messages delivery - messages can get lost
		693	without any of the processes realising it (i.e. you send messages a, b,
		694	and c, and the other side only receives messages a and c).
		695
		696	AEMP guarantees correct ordering, and the guarantee that there are no
		697	holes in the message sequence.
		698
		699	=item * In Erlang, processes can be declared dead and later be found to be
		700	alive.
		701
		702	In Erlang it can happen that a monitored process is declared dead and
		703	linked processes get killed, but later it turns out that the process is
		704	still alive - and can receive messages.
		705
		706	In AEMP, when port monitoring detects a port as dead, then that port will
		707	eventually be killed - it cannot happen that a node detects a port as dead
		708	and then later sends messages to it, finding it is still alive.
		709
		710	=item * Erlang can send messages to the wrong port, AEMP does not.
		711
		712	In Erlang it is quite possible that a node that restarts reuses a process
		713	ID known to other nodes for a completely different process, causing
		714	messages destined for that process to end up in an unrelated process.
		715
		716	AEMP never reuses port IDs, so old messages or old port IDs floating
		717	around in the network will not be sent to an unrelated port.
		718
		719	=item * Erlang uses unprotected connections, AEMP uses secure
		720	authentication and can use TLS.
		721
		722	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		723	securely authenticate nodes.
		724
		725	=item * The AEMP protocol is optimised for both text-based and binary
		726	communications.
		727
		728	The AEMP protocol, unlike the Erlang protocol, supports both
		729	language-independent text-only protocols (good for debugging) and binary,
		730	language-specific serialisers (e.g. Storable).
		731
		732	It has also been carefully designed to be implementable in other languages
		733	with a minimum of work while gracefully degrading fucntionality to make the
		734	protocol simple.
		735
		736	=item * AEMP has more flexible monitoring options than Erlang.
		737
		738	In Erlang, you can chose to receive I<all> exit signals as messages
		739	or I<none>, there is no in-between, so monitoring single processes is
		740	difficult to implement. Monitoring in AEMP is more flexible than in
		741	Erlang, as one can choose between automatic kill, exit message or callback
		742	on a per-process basis.
		743
		744	=item * Erlang tries to hide remote/local connections, AEMP does not.
		745
		746	Monitoring in Erlang is not an indicator of process death/crashes,
		747	as linking is (except linking is unreliable in Erlang).
		748
		749	In AEMP, you don't "look up" registered port names or send to named ports
		750	that might or might not be persistent. Instead, you normally spawn a port
		751	on the remote node. The init function monitors the you, and you monitor
		752	the remote port. Since both monitors are local to the node, they are much
		753	more reliable.
		754
		755	This also saves round-trips and avoids sending messages to the wrong port
		756	(hard to do in Erlang).
440		757
441	=back	758	=back
442		759
443	=head1 SEE ALSO	760	=head1 SEE ALSO
444		761

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.6 by root, Sat Aug 1 10:02:33 2009 UTC vs. Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.6 by root, Sat Aug 1 10:02:33 2009 UTC vs.
Revision 1.37 by root, Fri Aug 7 16:47:23 2009 UTC