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

Comparing cvsroot/AnyEvent-MP/MP.pm (file contents):
Revision 1.3 by root, Sat Aug 1 07:11:45 2009 UTC vs.
Revision 1.35 by root, Thu Aug 6 10:21:48 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	# linking two ports, so they both crash together
		29	lnk $port1, $port2;
		30
		31	# monitoring
		32	mon $port, $cb->(@msg) # callback is invoked on death
		33	mon $port, $otherport # kill otherport on abnormal death
		34	mon $port, $otherport, @msg # send message on death
		35
25	=head1 DESCRIPTION	36	=head1 DESCRIPTION
26		37
27	This module (-family) implements a simple message passing framework.	38	This module (-family) implements a simple message passing framework.
28		39
29	Despite its simplicity, you can securely message other processes running	40	Despite its simplicity, you can securely message other processes running
30	on the same or other hosts.	41	on the same or other hosts.
31		42
		43	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		44	manual page.
		45
		46	At the moment, this module family is severly broken and underdocumented,
		47	so do not use. This was uploaded mainly to reserve the CPAN namespace -
		48	stay tuned! The basic API should be finished, however.
		49
32	=head1 CONCEPTS	50	=head1 CONCEPTS
33		51
34	=over 4	52	=over 4
35		53
36	=item port	54	=item port
37		55
38	A port is something you can send messages to with the C<snd> function, and	56	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	57
40	messages they match, messages will not be queued.	58	Some ports allow you to register C<rcv> handlers that can match specific
		59	messages. All C<rcv> handlers will receive messages they match, messages
		60	will not be queued.
41		61
42	=item port id - C<noderef#portname>	62	=item port id - C<noderef#portname>
43		63
44	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	64	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).	65	separator, and a port name (a printable string of unspecified format). An
		66	exception is the the node port, whose ID is identical to its node
		67	reference.
46		68
47	=item node	69	=item node
48		70
49	A node is a single process containing at least one port - the node	71	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,	72	port. You can send messages to node ports to find existing ports or to
51	among other things.	73	create new ports, among other things.
52		74
53	Initially, nodes are either private (single-process only) or hidden	75	Nodes are either private (single-process only), slaves (connected to a
54	(connected to a master node only). Only when they epxlicitly "become	76	master node only) or public nodes (connectable from unrelated nodes).
55	public" can you send them messages from unrelated other nodes.
56		77
57	=item noderef - C<host:port,host:port...>, C<id@noderef, C<id>	78	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
58		79
59	A noderef is a string that either uniquely identifies a given node (for	80	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	81	private and slave nodes), or contains a recipe on how to reach a given
61	node (for public nodes).	82	node (for public nodes).
62		83
		84	This recipe is simply a comma-separated list of C<address:port> pairs (for
		85	TCP/IP, other protocols might look different).
		86
		87	Node references come in two flavours: resolved (containing only numerical
		88	addresses) or unresolved (where hostnames are used instead of addresses).
		89
		90	Before using an unresolved node reference in a message you first have to
		91	resolve it.
		92
63	=back	93	=back
64		94
65	=head1 VARIABLES/FUNCTIONS	95	=head1 VARIABLES/FUNCTIONS
66		96
67	=over 4	97	=over 4
68		98
69	=cut	99	=cut
70		100
71	package AnyEvent::MP;	101	package AnyEvent::MP;
72		102
73	use AnyEvent::MP::Util ();
74	use AnyEvent::MP::Node;	103	use AnyEvent::MP::Base;
75	use AnyEvent::MP::Transport;
76		104
77	use utf8;
78	use common::sense;	105	use common::sense;
79		106
80	use Carp ();	107	use Carp ();
81		108
82	use AE ();	109	use AE ();
83		110
84	use base "Exporter";	111	use base "Exporter";
85		112
86	our $VERSION = '0.0';	113	our $VERSION = '0.1';
87	our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_);	114	our @EXPORT = qw(
		115	NODE $NODE *SELF node_of _any_
		116	resolve_node initialise_node
		117	snd rcv mon kil reg psub
		118	port
		119	);
88		120
89	our $DEFAULT_SECRET;	121	our $SELF;
90	our $DEFAULT_PORT = "4040";
91		122
92	our $CONNECT_INTERVAL = 5; # new connect every 5s, at least	123	sub _self_die() {
93	our $CONNECT_TIMEOUT = 30; # includes handshake	124	my $msg = $@;
94		125	$msg =~ s/\n+$// unless ref $msg;
95	sub default_secret {	126	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	}	127	}
106		128
107	=item NODE / $NODE	129	=item $thisnode = NODE / $NODE
108		130
109	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	131	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	132	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.	133	to C<become_public> or C<become_slave>, after which all local port
		134	identifiers become invalid.
112		135
113	=cut	136	=item $noderef = node_of $port
114		137
115	our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie	138	Extracts and returns the noderef from a portid or a noderef.
116	our $PUBLIC = 0;
117	our $NODE;
118	our $PORT;
119		139
120	our %NODE; # node id to transport mapping, or "undef", for local node	140	=item initialise_node $noderef, $seednode, $seednode...
121	our %PORT; # local ports
122	our %LISTENER; # local transports
123		141
124	sub NODE() { $NODE }	142	=item initialise_node "slave/", $master, $master...
125		143
126	{	144	Before a node can talk to other nodes on the network it has to initialise
127	use POSIX ();	145	itself - the minimum a node needs to know is it's own name, and optionally
128	my $nodename = (POSIX::uname)[1];	146	it should know the noderefs of some other nodes in the network.
129	$NODE = "$$\@$nodename";
130	}
131		147
132	sub _ANY_() { 1 }	148	This function initialises a node - it must be called exactly once (or
133	sub _any_() { \&_ANY_ }	149	never) before calling other AnyEvent::MP functions.
134		150
135	sub add_node {	151	All arguments are noderefs, which can be either resolved or unresolved.
136	my ($noderef) = @_;
137		152
138	return $NODE{$noderef}	153	There are two types of networked nodes, public nodes and slave nodes:
139	if exists $NODE{$noderef};
140		154
141	for (split /,/, $noderef) {	155	=over 4
142	return $NODE{$noderef} = $NODE{$_}
143	if exists $NODE{$_};
144	}
145		156
146	# for indirect sends, use a different class	157	=item public nodes
147	my $node = new AnyEvent::MP::Node::Direct $noderef;
148		158
149	$NODE{$_} = $node	159	For public nodes, C<$noderef> must either be a (possibly unresolved)
150	for $noderef, split /,/, $noderef;	160	noderef, in which case it will be resolved, or C<undef> (or missing), in
		161	which case the noderef will be guessed.
151		162
152	$node	163	Afterwards, the node will bind itself on all endpoints and try to connect
153	}	164	to all additional C<$seednodes> that are specified. Seednodes are optional
		165	and can be used to quickly bootstrap the node into an existing network.
154		166
		167	=item slave nodes
		168
		169	When the C<$noderef> is the special string C<slave/>, then the node will
		170	become a slave node. Slave nodes cannot be contacted from outside and will
		171	route most of their traffic to the master node that they attach to.
		172
		173	At least one additional noderef is required: The node will try to connect
		174	to all of them and will become a slave attached to the first node it can
		175	successfully connect to.
		176
		177	=back
		178
		179	This function will block until all nodes have been resolved and, for slave
		180	nodes, until it has successfully established a connection to a master
		181	server.
		182
		183	Example: become a public node listening on the default node.
		184
		185	initialise_node;
		186
		187	Example: become a public node, and try to contact some well-known master
		188	servers to become part of the network.
		189
		190	initialise_node undef, "master1", "master2";
		191
		192	Example: become a public node listening on port C<4041>.
		193
		194	initialise_node 4041;
		195
		196	Example: become a public node, only visible on localhost port 4044.
		197
		198	initialise_node "locahost:4044";
		199
		200	Example: become a slave node to any of the specified master servers.
		201
		202	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		203
		204	=item $cv = resolve_node $noderef
		205
		206	Takes an unresolved node reference that may contain hostnames and
		207	abbreviated IDs, resolves all of them and returns a resolved node
		208	reference.
		209
		210	In addition to C<address:port> pairs allowed in resolved noderefs, the
		211	following forms are supported:
		212
		213	=over 4
		214
		215	=item the empty string
		216
		217	An empty-string component gets resolved as if the default port (4040) was
		218	specified.
		219
		220	=item naked port numbers (e.g. C<1234>)
		221
		222	These are resolved by prepending the local nodename and a colon, to be
		223	further resolved.
		224
		225	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		226
		227	These are resolved by using AnyEvent::DNS to resolve them, optionally
		228	looking up SRV records for the C<aemp=4040> port, if no port was
		229	specified.
		230
		231	=back
		232
		233	=item $SELF
		234
		235	Contains the current port id while executing C<rcv> callbacks or C<psub>
		236	blocks.
		237
		238	=item SELF, %SELF, @SELF...
		239
		240	Due to some quirks in how perl exports variables, it is impossible to
		241	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		242	module, but only C<$SELF> is currently used.
		243
155	=item snd $portid, type => @data	244	=item snd $port, type => @data
156		245
157	=item snd $portid, @msg	246	=item snd $port, @msg
158		247
159	Send the given message to the given port ID, which can identify either a	248	Send the given message to the given port ID, which can identify either
160	local or a remote port.	249	a local or a remote port, and can be either a string or soemthignt hat
		250	stringifies a sa port ID (such as a port object :).
161		251
162	While the message can be about anything, it is highly recommended to use	252	While the message can be about anything, it is highly recommended to use a
163	a constant string as first element.	253	string as first element (a portid, or some word that indicates a request
		254	type etc.).
164		255
165	The message data effectively becomes read-only after a call to this	256	The message data effectively becomes read-only after a call to this
166	function: modifying any argument is not allowed and can cause many	257	function: modifying any argument is not allowed and can cause many
167	problems.	258	problems.
168		259
…		…
170	JSON is used, then only strings, numbers and arrays and hashes consisting	261	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	262	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	263	that Storable can serialise and deserialise is allowed, and for the local
173	node, anything can be passed.	264	node, anything can be passed.
174		265
175	=cut	266	=item $local_port = port
176		267
177	sub snd($@) {	268	Create a new local port object that can be used either as a pattern
178	my ($noderef, $port) = split /#/, shift, 2;	269	matching port ("full port") or a single-callback port ("miniport"),
		270	depending on how C<rcv> callbacks are bound to the object.
179		271
180	add_node $noderef	272	=item $port = port { my @msg = @_; $finished }
181	unless exists $NODE{$noderef};
182		273
183	$NODE{$noderef}->send (["$port", [@_]]);	274	Creates a "miniport", that is, a very lightweight port without any pattern
		275	matching behind it, and returns its ID. Semantically the same as creating
		276	a port and calling C<rcv $port, $callback> on it.
		277
		278	The block will be called for every message received on the port. When the
		279	callback returns a true value its job is considered "done" and the port
		280	will be destroyed. Otherwise it will stay alive.
		281
		282	The message will be passed as-is, no extra argument (i.e. no port id) will
		283	be passed to the callback.
		284
		285	If you need the local port id in the callback, this works nicely:
		286
		287	my $port; $port = port {
		288	snd $otherport, reply => $port;
		289	};
		290
		291	=cut
		292
		293	sub rcv($@);
		294
		295	sub port(;&) {
		296	my $id = "$UNIQ." . $ID++;
		297	my $port = "$NODE#$id";
		298
		299	if (@_) {
		300	rcv $port, shift;
		301	} else {
		302	$PORT{$id} = sub { }; # nop
		303	}
		304
		305	$port
184	}	306	}
185		307
		308	=item reg $port, $name
		309
		310	Registers the given port under the name C<$name>. If the name already
		311	exists it is replaced.
		312
		313	A port can only be registered under one well known name.
		314
		315	A port automatically becomes unregistered when it is killed.
		316
		317	=cut
		318
		319	sub reg(@) {
		320	my ($port, $name) = @_;
		321
		322	$REG{$name} = $port;
		323	}
		324
186	=item rcv $portid, type => $callback->(@msg)	325	=item rcv $port, $callback->(@msg)
187		326
		327	Replaces the callback on the specified miniport (after converting it to
		328	one if required).
		329
		330	=item rcv $port, tagstring => $callback->(@msg), ...
		331
188	=item rcv $portid, $smartmatch => $callback->(@msg)	332	=item rcv $port, $smartmatch => $callback->(@msg), ...
189		333
190	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	334	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
191		335
192	Register a callback on the port identified by C<$portid>, which I<must> be	336	Register callbacks to be called on matching messages on the given full
193	a local port.	337	port (after converting it to one if required).
194		338
195	The callback has to return a true value when its work is done, after	339	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	340	which is will be removed, or a false value in which case it will stay
197	registered.	341	registered.
198		342
		343	The global C<$SELF> (exported by this module) contains C<$port> while
		344	executing the callback.
		345
		346	Runtime errors wdurign callback execution will result in the port being
		347	C<kil>ed.
		348
199	If the match is an array reference, then it will be matched against the	349	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	350	first elements of the message, otherwise only the first element is being
201	matched.	351	matched.
202		352
203	Any element in the match that is specified as C<_any_> (a function	353	Any element in the match that is specified as C<_any_> (a function
…		…
208	also the most efficient match (by far).	358	also the most efficient match (by far).
209		359
210	=cut	360	=cut
211		361
212	sub rcv($@) {	362	sub rcv($@) {
213	my ($port, $match, $cb) = @_;	363	my $port = shift;
214
215	my $port = $PORT{$port}
216	or do {
217	my ($noderef, $lport) = split /#/, $port;	364	my ($noderef, $portid) = split /#/, $port, 2;
218	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	365
		366	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
219	or Carp::croak "$port: can only rcv on local ports";	367	or Carp::croak "$port: rcv can only be called on local ports, caught";
220		368
221	$PORT{$lport}	369	if (@_ == 1) {
222	or Carp::croak "$port: port does not exist";	370	my $cb = shift;
		371	delete $PORT_DATA{$portid};
		372	$PORT{$portid} = sub {
		373	local $SELF = $port;
		374	eval {
223		375	&$cb
224	$PORT{$port} = $PORT{$lport} # also return	376	and kil $port;
		377	};
		378	_self_die if $@;
225	};	379	};
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 {	380	} else {
235	push @{ $port->{any} }, [$cb, $match];	381	my $self = $PORT_DATA{$portid} \|\|= do {
236	}	382	my $self = bless {
237	}	383	id => $port,
		384	}, "AnyEvent::MP::Port";
238		385
239	sub _inject {	386	$PORT{$portid} = sub {
240	my ($port, $msg) = @{+shift};	387	local $SELF = $port;
241		388
242	$port = $PORT{$port}	389	eval {
243	or return;	390	for (@{ $self->{rc0}{$_[0]} }) {
244
245	@_ = @$msg;
246
247	for (@{ $port->{rc0}{$msg->[0]} }) {
248	$_ && &{$_->[0]}	391	$_ && &{$_->[0]}
249	&& undef $_;	392	&& 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	];	393	}
		394
		395	for (@{ $self->{rcv}{$_[0]} }) {
		396	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		397	&& &{$_->[0]}
		398	&& undef $_;
		399	}
		400
		401	for (@{ $self->{any} }) {
		402	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		403	&& &{$_->[0]}
		404	&& undef $_;
		405	}
298	}	406	};
299	$cv->end;	407	_self_die if $@;
300	};	408	};
301		409
302	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;	410	$self
303	#	411	};
304	# for (@ipv4) {	412
305	# push @res, [	413	"AnyEvent::MP::Port" eq ref $self
306	# $pri,	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
307	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,	415
308	# ];	416	while (@_) {
309	# }	417	my ($match, $cb) = splice @_, 0, 2;
		418
		419	if (!ref $match) {
		420	push @{ $self->{rc0}{$match} }, [$cb];
		421	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		422	my ($type, @match) = @$match;
		423	@match
		424	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		425	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
310	} else {	426	} else {
311	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	427	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	}	428	}
325	}	429	}
326	}	430	}
327		431
328	$cv->end;	432	$port
329
330	$cv
331	}	433	}
332		434
333	sub become_public {	435	=item $closure = psub { BLOCK }
334	return if $PUBLIC;
335		436
336	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	437	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
337	my @args = @_;	438	closure is executed, sets up the environment in the same way as in C<rcv>
		439	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
338		440
339	$NODE = (normalise_noderef $noderef)->recv;	441	This is useful when you register callbacks from C<rcv> callbacks:
340		442
341	for my $t (split /,/, $NODE) {	443	rcv delayed_reply => sub {
342	$NODE{$t} = $NODE{""};	444	my ($delay, @reply) = @_;
343		445	my $timer = AE::timer $delay, 0, psub {
344	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	446	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	;	447	};
		448	};
		449
		450	=cut
		451
		452	sub psub(&) {
		453	my $cb = shift;
		454
		455	my $port = $SELF
		456	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		457
		458	sub {
		459	local $SELF = $port;
		460
		461	if (wantarray) {
		462	my @res = eval { &$cb };
		463	_self_die if $@;
		464	@res
		465	} else {
		466	my $res = eval { &$cb };
		467	_self_die if $@;
		468	$res
		469	}
362	}	470	}
363
364	$PUBLIC = 1;
365	}	471	}
366		472
367	#############################################################################	473	=item $guard = mon $port, $cb->(@reason)
368	# self node code
369		474
370	sub _new_port($) {	475	=item $guard = mon $port, $otherport
371	my ($name) = @_;
372		476
		477	=item $guard = mon $port, $otherport, @msg
		478
		479	Monitor the given port and do something when the port is killed.
		480
		481	In the first form, the callback is simply called with any number
		482	of C<@reason> elements (no @reason means that the port was deleted
		483	"normally"). Note also that I<< the callback B<must> never die >>, so use
		484	C<eval> if unsure.
		485
		486	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
		487	a @reason was specified, i.e. on "normal" kils nothing happens, while
		488	under all other conditions, the other port is killed with the same reason.
		489
		490	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
		491
		492	Example: call a given callback when C<$port> is killed.
		493
		494	mon $port, sub { warn "port died because of <@_>\n" };
		495
		496	Example: kill ourselves when C<$port> is killed abnormally.
		497
		498	mon $port, $self;
		499
		500	Example: send us a restart message another C<$port> is killed.
		501
		502	mon $port, $self => "restart";
		503
		504	=cut
		505
		506	sub mon {
373	my ($noderef, $portname) = split /#/, $name;	507	my ($noderef, $port) = split /#/, shift, 2;
374		508
375	$PORT{$name} =	509	my $node = $NODE{$noderef} \|\| add_node $noderef;
376	$PORT{$portname} = {	510
377	names => [$name, $portname],	511	my $cb = shift;
		512
		513	unless (ref $cb) {
		514	if (@_) {
		515	# send a kill info message
		516	my (@msg) = ($cb, @_);
		517	$cb = sub { snd @msg, @_ };
		518	} else {
		519	# simply kill other port
		520	my $port = $cb;
		521	$cb = sub { kil $port, @_ if @_ };
		522	}
378	};	523	}
		524
		525	$node->monitor ($port, $cb);
		526
		527	defined wantarray
		528	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
379	}	529	}
380		530
381	$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE;	531	=item $guard = mon_guard $port, $ref, $ref...
382	_new_port "";
383		532
384	rcv "", relay => \&snd;	533	Monitors the given C<$port> and keeps the passed references. When the port
		534	is killed, the references will be freed.
		535
		536	Optionally returns a guard that will stop the monitoring.
		537
		538	This function is useful when you create e.g. timers or other watchers and
		539	want to free them when the port gets killed:
		540
		541	$port->rcv (start => sub {
		542	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		543	undef $timer if 0.9 < rand;
		544	});
		545	});
		546
		547	=cut
		548
		549	sub mon_guard {
		550	my ($port, @refs) = @_;
		551
		552	mon $port, sub { 0 && @refs }
		553	}
		554
		555	=item lnk $port1, $port2
		556
		557	Link two ports. This is simply a shorthand for:
		558
		559	mon $port1, $port2;
		560	mon $port2, $port1;
		561
		562	It means that if either one is killed abnormally, the other one gets
		563	killed as well.
		564
		565	=item kil $port[, @reason]
		566
		567	Kill the specified port with the given C<@reason>.
		568
		569	If no C<@reason> is specified, then the port is killed "normally" (linked
		570	ports will not be kileld, or even notified).
		571
		572	Otherwise, linked ports get killed with the same reason (second form of
		573	C<mon>, see below).
		574
		575	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		576	will be reported as reason C<< die => $@ >>.
		577
		578	Transport/communication errors are reported as C<< transport_error =>
		579	$message >>.
		580
		581	=back
		582
		583	=head1 NODE MESSAGES
		584
		585	Nodes understand the following messages sent to them. Many of them take
		586	arguments called C<@reply>, which will simply be used to compose a reply
		587	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
		588	the remaining arguments are simply the message data.
		589
		590	While other messages exist, they are not public and subject to change.
		591
		592	=over 4
		593
		594	=cut
		595
		596	=item lookup => $name, @reply
		597
		598	Replies with the port ID of the specified well-known port, or C<undef>.
		599
		600	=item devnull => ...
		601
		602	Generic data sink/CPU heat conversion.
		603
		604	=item relay => $port, @msg
		605
		606	Simply forwards the message to the given port.
		607
		608	=item eval => $string[ @reply]
		609
		610	Evaluates the given string. If C<@reply> is given, then a message of the
		611	form C<@reply, $@, @evalres> is sent.
		612
		613	Example: crash another node.
		614
		615	snd $othernode, eval => "exit";
		616
		617	=item time => @reply
		618
		619	Replies the the current node time to C<@reply>.
		620
		621	Example: tell the current node to send the current time to C<$myport> in a
		622	C<timereply> message.
		623
		624	snd $NODE, time => $myport, timereply => 1, 2;
		625	# => snd $myport, timereply => 1, 2, <time>
		626
		627	=back
		628
		629	=head1 AnyEvent::MP vs. Distributed Erlang
		630
		631	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
		632	== aemp node, Erlang process == aemp port), so many of the documents and
		633	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		634	sample:
		635
		636	http://www.Erlang.se/doc/programming_rules.shtml
		637	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		638	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		639	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		640
		641	Despite the similarities, there are also some important differences:
		642
		643	=over 4
		644
		645	=item * Node references contain the recipe on how to contact them.
		646
		647	Erlang relies on special naming and DNS to work everywhere in the
		648	same way. AEMP relies on each node knowing it's own address(es), with
		649	convenience functionality.
		650
		651	This means that AEMP requires a less tightly controlled environment at the
		652	cost of longer node references and a slightly higher management overhead.
		653
		654	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		655
		656	Erlang uses processes that selctively receive messages, and therefore
		657	needs a queue. AEMP is event based, queuing messages would serve no useful
		658	purpose.
		659
		660	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
		661
		662	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		663
		664	Sending messages in Erlang is synchronous and blocks the process. AEMP
		665	sends are immediate, connection establishment is handled in the
		666	background.
		667
		668	=item * Erlang can silently lose messages, AEMP cannot.
		669
		670	Erlang makes few guarantees on messages delivery - messages can get lost
		671	without any of the processes realising it (i.e. you send messages a, b,
		672	and c, and the other side only receives messages a and c).
		673
		674	AEMP guarantees correct ordering, and the guarantee that there are no
		675	holes in the message sequence.
		676
		677	=item * In Erlang, processes can be declared dead and later be found to be
		678	alive.
		679
		680	In Erlang it can happen that a monitored process is declared dead and
		681	linked processes get killed, but later it turns out that the process is
		682	still alive - and can receive messages.
		683
		684	In AEMP, when port monitoring detects a port as dead, then that port will
		685	eventually be killed - it cannot happen that a node detects a port as dead
		686	and then later sends messages to it, finding it is still alive.
		687
		688	=item * Erlang can send messages to the wrong port, AEMP does not.
		689
		690	In Erlang it is quite possible that a node that restarts reuses a process
		691	ID known to other nodes for a completely different process, causing
		692	messages destined for that process to end up in an unrelated process.
		693
		694	AEMP never reuses port IDs, so old messages or old port IDs floating
		695	around in the network will not be sent to an unrelated port.
		696
		697	=item * Erlang uses unprotected connections, AEMP uses secure
		698	authentication and can use TLS.
		699
		700	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		701	securely authenticate nodes.
		702
		703	=item * The AEMP protocol is optimised for both text-based and binary
		704	communications.
		705
		706	The AEMP protocol, unlike the Erlang protocol, supports both
		707	language-independent text-only protocols (good for debugging) and binary,
		708	language-specific serialisers (e.g. Storable).
		709
		710	It has also been carefully designed to be implementable in other languages
		711	with a minimum of work while gracefully degrading fucntionality to make the
		712	protocol simple.
		713
		714	=item * AEMP has more flexible monitoring options than Erlang.
		715
		716	In Erlang, you can chose to receive I<all> exit signals as messages
		717	or I<none>, there is no in-between, so monitoring single processes is
		718	difficult to implement. Monitoring in AEMP is more flexible than in
		719	Erlang, as one can choose between automatic kill, exit message or callback
		720	on a per-process basis.
		721
		722	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.
		723
		724	Monitoring in Erlang is not an indicator of process death/crashes,
		725	as linking is (except linking is unreliable in Erlang). In AEMP, the
		726	semantics of monitoring and linking are identical, linking is simply
		727	two-way monitoring with automatic kill.
385		728
386	=back	729	=back
387		730
388	=head1 SEE ALSO	731	=head1 SEE ALSO
389		732

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Revision 1.35 by root, Thu Aug 6 10:21:48 2009 UTC