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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.5 by root, Sat Aug 1 07:44:02 2009 UTC vs.
Revision 1.49 by root, Thu Aug 13 15:29:58 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
		13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# initialise the node so it can send/receive messages
		16	initialise_node; # -OR-
		17	initialise_node "localhost:4040"; # -OR-
		18	initialise_node "slave/", "localhost:4040"
		19
		20	# ports are message endpoints
		21
		22	# sending messages
12	snd $port, type => data...;	23	snd $port, type => data...;
		24	snd $port, @msg;
		25	snd @msg_with_first_element_being_a_port;
13		26
		27	# creating/using miniports
		28	my $miniport = port { my @msg = @_; 0 };
		29
		30	# creating/using full ports
		31	my $port = port;
14	rcv $port, smartmatch => $cb->($port, @msg);	32	rcv $port, smartmatch => $cb->(@msg);
15
16	# examples:
17	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	33	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
18	rcv $port1, pong => sub { warn "pong received\n" };	34	rcv $port, pong => sub { warn "pong received\n"; 0 };
19	snd $port2, ping => $port1;
20		35
21	# more, smarter, matches (_any_ is exported by this module)	36	# more, smarter, matches (_any_ is exported by this module)
22	rcv $port, [child_died => $pid] => sub { ...	37	rcv $port, [child_died => $pid] => sub { ...
23	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	38	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
24		39
		40	# create a port on another node
		41	my $port = spawn $node, $initfunc, @initdata;
		42
		43	# monitoring
		44	mon $port, $cb->(@msg) # callback is invoked on death
		45	mon $port, $otherport # kill otherport on abnormal death
		46	mon $port, $otherport, @msg # send message on death
		47
		48	=head1 CURRENT STATUS
		49
		50	AnyEvent::MP - stable API, should work
		51	AnyEvent::MP::Intro - outdated
		52	AnyEvent::MP::Kernel - WIP
		53	AnyEvent::MP::Transport - mostly stable
		54
		55	stay tuned.
		56
25	=head1 DESCRIPTION	57	=head1 DESCRIPTION
26		58
27	This module (-family) implements a simple message passing framework.	59	This module (-family) implements a simple message passing framework.
28		60
29	Despite its simplicity, you can securely message other processes running	61	Despite its simplicity, you can securely message other processes running
30	on the same or other hosts.	62	on the same or other hosts.
31		63
		64	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		65	manual page.
		66
		67	At the moment, this module family is severly broken and underdocumented,
		68	so do not use. This was uploaded mainly to reserve the CPAN namespace -
		69	stay tuned!
		70
32	=head1 CONCEPTS	71	=head1 CONCEPTS
33		72
34	=over 4	73	=over 4
35		74
36	=item port	75	=item port
37		76
38	A port is something you can send messages to with the C<snd> function, and	77	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	78
40	messages they match, messages will not be queued.	79	Some ports allow you to register C<rcv> handlers that can match specific
		80	messages. All C<rcv> handlers will receive messages they match, messages
		81	will not be queued.
41		82
42	=item port id - C<noderef#portname>	83	=item port id - C<noderef#portname>
43		84
44	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	85	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).	86	separator, and a port name (a printable string of unspecified format). An
		87	exception is the the node port, whose ID is identical to its node
		88	reference.
46		89
47	=item node	90	=item node
48		91
49	A node is a single process containing at least one port - the node	92	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,	93	port. You can send messages to node ports to find existing ports or to
51	among other things.	94	create new ports, among other things.
52		95
53	Initially, nodes are either private (single-process only) or hidden	96	Nodes are either private (single-process only), slaves (connected to a
54	(connected to a master node only). Only when they epxlicitly "become	97	master node only) or public nodes (connectable from unrelated nodes).
55	public" can you send them messages from unrelated other nodes.
56		98
57	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	99	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
58		100
59	A noderef is a string that either uniquely identifies a given node (for	101	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	102	private and slave nodes), or contains a recipe on how to reach a given
61	node (for public nodes).	103	node (for public nodes).
62		104
		105	This recipe is simply a comma-separated list of C<address:port> pairs (for
		106	TCP/IP, other protocols might look different).
		107
		108	Node references come in two flavours: resolved (containing only numerical
		109	addresses) or unresolved (where hostnames are used instead of addresses).
		110
		111	Before using an unresolved node reference in a message you first have to
		112	resolve it.
		113
63	=back	114	=back
64		115
65	=head1 VARIABLES/FUNCTIONS	116	=head1 VARIABLES/FUNCTIONS
66		117
67	=over 4	118	=over 4
68		119
69	=cut	120	=cut
70		121
71	package AnyEvent::MP;	122	package AnyEvent::MP;
72		123
73	use AnyEvent::MP::Util ();
74	use AnyEvent::MP::Node;	124	use AnyEvent::MP::Kernel;
75	use AnyEvent::MP::Transport;
76		125
77	use utf8;
78	use common::sense;	126	use common::sense;
79		127
80	use Carp ();	128	use Carp ();
81		129
82	use AE ();	130	use AE ();
83		131
84	use base "Exporter";	132	use base "Exporter";
85		133
86	our $VERSION = '0.0';	134	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
87	our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_);
88		135
89	our $DEFAULT_SECRET;	136	our @EXPORT = qw(
90	our $DEFAULT_PORT = "4040";	137	NODE $NODE *SELF node_of _any_
		138	resolve_node initialise_node
		139	snd rcv mon kil reg psub spawn
		140	port
		141	);
91		142
92	our $CONNECT_INTERVAL = 5; # new connect every 5s, at least	143	our $SELF;
93	our $CONNECT_TIMEOUT = 30; # includes handshake
94		144
95	sub default_secret {	145	sub _self_die() {
96	unless (defined $DEFAULT_SECRET) {	146	my $msg = $@;
97	if (open my $fh, "<$ENV{HOME}/.aemp-secret") {	147	$msg =~ s/\n+$// unless ref $msg;
98	sysread $fh, $DEFAULT_SECRET, -s $fh;	148	kil $SELF, die => $msg;
99	} else {
100	$DEFAULT_SECRET = AnyEvent::MP::Util::nonce 32;
101	}
102	}
103
104	$DEFAULT_SECRET
105	}	149	}
106		150
107	=item NODE / $NODE	151	=item $thisnode = NODE / $NODE
108		152
109	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	153	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	154	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.	155	to C<become_public> or C<become_slave>, after which all local port
		156	identifiers become invalid.
112		157
113	=cut	158	=item $noderef = node_of $port
114		159
115	our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie	160	Extracts and returns the noderef from a portid or a noderef.
116	our $PUBLIC = 0;
117	our $NODE;
118	our $PORT;
119		161
120	our %NODE; # node id to transport mapping, or "undef", for local node	162	=item initialise_node $noderef, $seednode, $seednode...
121	our %PORT; # local ports
122	our %LISTENER; # local transports
123		163
124	sub NODE() { $NODE }	164	=item initialise_node "slave/", $master, $master...
125		165
126	{	166	Before a node can talk to other nodes on the network it has to initialise
127	use POSIX ();	167	itself - the minimum a node needs to know is it's own name, and optionally
128	my $nodename = (POSIX::uname)[1];	168	it should know the noderefs of some other nodes in the network.
129	$NODE = "$$\@$nodename";
130	}
131		169
132	sub _ANY_() { 1 }	170	This function initialises a node - it must be called exactly once (or
133	sub _any_() { \&_ANY_ }	171	never) before calling other AnyEvent::MP functions.
134		172
135	sub add_node {	173	All arguments (optionally except for the first) are noderefs, which can be
136	my ($noderef) = @_;	174	either resolved or unresolved.
137		175
138	return $NODE{$noderef}	176	The first argument will be looked up in the configuration database first
139	if exists $NODE{$noderef};	177	(if it is C<undef> then the current nodename will be used instead) to find
		178	the relevant configuration profile (see L<aemp>). If none is found then
		179	the default configuration is used. The configuration supplies additional
		180	seed/master nodes and can override the actual noderef.
140		181
141	for (split /,/, $noderef) {	182	There are two types of networked nodes, public nodes and slave nodes:
142	return $NODE{$noderef} = $NODE{$_}
143	if exists $NODE{$_};
144	}
145		183
146	# for indirect sends, use a different class	184	=over 4
147	my $node = new AnyEvent::MP::Node::Direct $noderef;
148		185
149	$NODE{$_} = $node	186	=item public nodes
150	for $noderef, split /,/, $noderef;
151		187
152	$node	188	For public nodes, C<$noderef> (supplied either directly to
153	}	189	C<initialise_node> or indirectly via a profile or the nodename) must be a
		190	noderef (possibly unresolved, in which case it will be resolved).
154		191
		192	After resolving, the node will bind itself on all endpoints and try to
		193	connect to all additional C<$seednodes> that are specified. Seednodes are
		194	optional and can be used to quickly bootstrap the node into an existing
		195	network.
		196
		197	=item slave nodes
		198
		199	When the C<$noderef> (either as given or overriden by the config file)
		200	is the special string C<slave/>, then the node will become a slave
		201	node. Slave nodes cannot be contacted from outside and will route most of
		202	their traffic to the master node that they attach to.
		203
		204	At least one additional noderef is required (either by specifying it
		205	directly or because it is part of the configuration profile): The node
		206	will try to connect to all of them and will become a slave attached to the
		207	first node it can successfully connect to.
		208
		209	=back
		210
		211	This function will block until all nodes have been resolved and, for slave
		212	nodes, until it has successfully established a connection to a master
		213	server.
		214
		215	Example: become a public node listening on the guessed noderef, or the one
		216	specified via C<aemp> for the current node. This should be the most common
		217	form of invocation for "daemon"-type nodes.
		218
		219	initialise_node;
		220
		221	Example: become a slave node to any of the the seednodes specified via
		222	C<aemp>. This form is often used for commandline clients.
		223
		224	initialise_node "slave/";
		225
		226	Example: become a slave node to any of the specified master servers. This
		227	form is also often used for commandline clients.
		228
		229	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		230
		231	Example: become a public node, and try to contact some well-known master
		232	servers to become part of the network.
		233
		234	initialise_node undef, "master1", "master2";
		235
		236	Example: become a public node listening on port C<4041>.
		237
		238	initialise_node 4041;
		239
		240	Example: become a public node, only visible on localhost port 4044.
		241
		242	initialise_node "localhost:4044";
		243
		244	=item $cv = resolve_node $noderef
		245
		246	Takes an unresolved node reference that may contain hostnames and
		247	abbreviated IDs, resolves all of them and returns a resolved node
		248	reference.
		249
		250	In addition to C<address:port> pairs allowed in resolved noderefs, the
		251	following forms are supported:
		252
		253	=over 4
		254
		255	=item the empty string
		256
		257	An empty-string component gets resolved as if the default port (4040) was
		258	specified.
		259
		260	=item naked port numbers (e.g. C<1234>)
		261
		262	These are resolved by prepending the local nodename and a colon, to be
		263	further resolved.
		264
		265	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		266
		267	These are resolved by using AnyEvent::DNS to resolve them, optionally
		268	looking up SRV records for the C<aemp=4040> port, if no port was
		269	specified.
		270
		271	=back
		272
		273	=item $SELF
		274
		275	Contains the current port id while executing C<rcv> callbacks or C<psub>
		276	blocks.
		277
		278	=item SELF, %SELF, @SELF...
		279
		280	Due to some quirks in how perl exports variables, it is impossible to
		281	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		282	module, but only C<$SELF> is currently used.
		283
155	=item snd $portid, type => @data	284	=item snd $port, type => @data
156		285
157	=item snd $portid, @msg	286	=item snd $port, @msg
158		287
159	Send the given message to the given port ID, which can identify either a	288	Send the given message to the given port ID, which can identify either
160	local or a remote port.	289	a local or a remote port, and can be either a string or soemthignt hat
		290	stringifies a sa port ID (such as a port object :).
161		291
162	While the message can be about anything, it is highly recommended to use	292	While the message can be about anything, it is highly recommended to use a
163	a constant string as first element.	293	string as first element (a portid, or some word that indicates a request
		294	type etc.).
164		295
165	The message data effectively becomes read-only after a call to this	296	The message data effectively becomes read-only after a call to this
166	function: modifying any argument is not allowed and can cause many	297	function: modifying any argument is not allowed and can cause many
167	problems.	298	problems.
168		299
…		…
170	JSON is used, then only strings, numbers and arrays and hashes consisting	301	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	302	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	303	that Storable can serialise and deserialise is allowed, and for the local
173	node, anything can be passed.	304	node, anything can be passed.
174		305
175	=cut	306	=item $local_port = port
176		307
177	sub snd(@) {	308	Create a new local port object that can be used either as a pattern
178	my ($noderef, $port) = split /#/, shift, 2;	309	matching port ("full port") or a single-callback port ("miniport"),
		310	depending on how C<rcv> callbacks are bound to the object.
179		311
180	add_node $noderef	312	=item $port = port { my @msg = @_; $finished }
181	unless exists $NODE{$noderef};
182		313
183	$NODE{$noderef}->send (["$port", [@_]]);	314	Creates a "miniport", that is, a very lightweight port without any pattern
		315	matching behind it, and returns its ID. Semantically the same as creating
		316	a port and calling C<rcv $port, $callback> on it.
		317
		318	The block will be called for every message received on the port. When the
		319	callback returns a true value its job is considered "done" and the port
		320	will be destroyed. Otherwise it will stay alive.
		321
		322	The message will be passed as-is, no extra argument (i.e. no port id) will
		323	be passed to the callback.
		324
		325	If you need the local port id in the callback, this works nicely:
		326
		327	my $port; $port = port {
		328	snd $otherport, reply => $port;
		329	};
		330
		331	=cut
		332
		333	sub rcv($@);
		334
		335	sub port(;&) {
		336	my $id = "$UNIQ." . $ID++;
		337	my $port = "$NODE#$id";
		338
		339	if (@_) {
		340	rcv $port, shift;
		341	} else {
		342	$PORT{$id} = sub { }; # nop
		343	}
		344
		345	$port
184	}	346	}
185		347
		348	=item reg $port, $name
		349
		350	=item reg $name
		351
		352	Registers the given port (or C<$SELF><<< if missing) under the name
		353	C<$name>. If the name already exists it is replaced.
		354
		355	A port can only be registered under one well known name.
		356
		357	A port automatically becomes unregistered when it is killed.
		358
		359	=cut
		360
		361	sub reg(@) {
		362	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		363
		364	$REG{$_[0]} = $port;
		365	}
		366
186	=item rcv $portid, type => $callback->(@msg)	367	=item rcv $port, $callback->(@msg)
187		368
		369	Replaces the callback on the specified miniport (after converting it to
		370	one if required).
		371
		372	=item rcv $port, tagstring => $callback->(@msg), ...
		373
188	=item rcv $portid, $smartmatch => $callback->(@msg)	374	=item rcv $port, $smartmatch => $callback->(@msg), ...
189		375
190	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	376	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
191		377
192	Register a callback on the port identified by C<$portid>, which I<must> be	378	Register callbacks to be called on matching messages on the given full
193	a local port.	379	port (after converting it to one if required) and return the port.
194		380
195	The callback has to return a true value when its work is done, after	381	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	382	which is will be removed, or a false value in which case it will stay
197	registered.	383	registered.
198		384
		385	The global C<$SELF> (exported by this module) contains C<$port> while
		386	executing the callback.
		387
		388	Runtime errors during callback execution will result in the port being
		389	C<kil>ed.
		390
199	If the match is an array reference, then it will be matched against the	391	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	392	first elements of the message, otherwise only the first element is being
201	matched.	393	matched.
202		394
203	Any element in the match that is specified as C<_any_> (a function	395	Any element in the match that is specified as C<_any_> (a function
…		…
205		397
206	While not required, it is highly recommended that the first matching	398	While not required, it is highly recommended that the first matching
207	element is a string identifying the message. The one-string-only match is	399	element is a string identifying the message. The one-string-only match is
208	also the most efficient match (by far).	400	also the most efficient match (by far).
209		401
		402	Example: create a port and bind receivers on it in one go.
		403
		404	my $port = rcv port,
		405	msg1 => sub { ...; 0 },
		406	msg2 => sub { ...; 0 },
		407	;
		408
		409	Example: create a port, bind receivers and send it in a message elsewhere
		410	in one go:
		411
		412	snd $otherport, reply =>
		413	rcv port,
		414	msg1 => sub { ...; 0 },
		415	...
		416	;
		417
210	=cut	418	=cut
211		419
212	sub rcv($@) {	420	sub rcv($@) {
213	my ($port, $match, $cb) = @_;	421	my $port = shift;
214
215	my $port = $PORT{$port}
216	or do {
217	my ($noderef, $lport) = split /#/, $port;	422	my ($noderef, $portid) = split /#/, $port, 2;
218	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	423
		424	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
219	or Carp::croak "$port: can only rcv on local ports";	425	or Carp::croak "$port: rcv can only be called on local ports, caught";
220		426
221	$PORT{$lport}	427	if (@_ == 1) {
222	or Carp::croak "$port: port does not exist";	428	my $cb = shift;
		429	delete $PORT_DATA{$portid};
		430	$PORT{$portid} = sub {
		431	local $SELF = $port;
		432	eval {
223		433	&$cb
224	$PORT{$port} = $PORT{$lport} # also return	434	and kil $port;
		435	};
		436	_self_die if $@;
225	};	437	};
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 {	438	} else {
235	push @{ $port->{any} }, [$cb, $match];	439	my $self = $PORT_DATA{$portid} \|\|= do {
236	}	440	my $self = bless {
237	}	441	id => $port,
		442	}, "AnyEvent::MP::Port";
238		443
239	sub _inject {	444	$PORT{$portid} = sub {
240	my ($port, $msg) = @{+shift};	445	local $SELF = $port;
241		446
242	$port = $PORT{$port}	447	eval {
243	or return;	448	for (@{ $self->{rc0}{$_[0]} }) {
244
245	@_ = @$msg;
246
247	for (@{ $port->{rc0}{$msg->[0]} }) {
248	$_ && &{$_->[0]}	449	$_ && &{$_->[0]}
249	&& undef $_;	450	&& 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	];	451	}
		452
		453	for (@{ $self->{rcv}{$_[0]} }) {
		454	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		455	&& &{$_->[0]}
		456	&& undef $_;
		457	}
		458
		459	for (@{ $self->{any} }) {
		460	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		461	&& &{$_->[0]}
		462	&& undef $_;
		463	}
298	}	464	};
299	$cv->end;	465	_self_die if $@;
300	};	466	};
301		467
302	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;	468	$self
303	#	469	};
304	# for (@ipv4) {	470
305	# push @res, [	471	"AnyEvent::MP::Port" eq ref $self
306	# $pri,	472	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
307	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,	473
308	# ];	474	while (@_) {
309	# }	475	my ($match, $cb) = splice @_, 0, 2;
		476
		477	if (!ref $match) {
		478	push @{ $self->{rc0}{$match} }, [$cb];
		479	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		480	my ($type, @match) = @$match;
		481	@match
		482	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		483	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
310	} else {	484	} else {
311	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	485	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	}	486	}
325	}	487	}
326	}	488	}
327		489
328	$cv->end;	490	$port
329
330	$cv
331	}	491	}
332		492
333	sub become_public {	493	=item $closure = psub { BLOCK }
334	return if $PUBLIC;
335		494
336	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	495	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
337	my @args = @_;	496	closure is executed, sets up the environment in the same way as in C<rcv>
		497	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
338		498
339	$NODE = (normalise_noderef $noderef)->recv;	499	This is useful when you register callbacks from C<rcv> callbacks:
340		500
341	for my $t (split /,/, $NODE) {	501	rcv delayed_reply => sub {
342	$NODE{$t} = $NODE{""};	502	my ($delay, @reply) = @_;
343		503	my $timer = AE::timer $delay, 0, psub {
344	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	504	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	;	505	};
		506	};
		507
		508	=cut
		509
		510	sub psub(&) {
		511	my $cb = shift;
		512
		513	my $port = $SELF
		514	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		515
		516	sub {
		517	local $SELF = $port;
		518
		519	if (wantarray) {
		520	my @res = eval { &$cb };
		521	_self_die if $@;
		522	@res
		523	} else {
		524	my $res = eval { &$cb };
		525	_self_die if $@;
		526	$res
		527	}
362	}	528	}
		529	}
363		530
364	$PUBLIC = 1;	531	=item $guard = mon $port, $cb->(@reason)
		532
		533	=item $guard = mon $port, $rcvport
		534
		535	=item $guard = mon $port
		536
		537	=item $guard = mon $port, $rcvport, @msg
		538
		539	Monitor the given port and do something when the port is killed or
		540	messages to it were lost, and optionally return a guard that can be used
		541	to stop monitoring again.
		542
		543	C<mon> effectively guarantees that, in the absence of hardware failures,
		544	that after starting the monitor, either all messages sent to the port
		545	will arrive, or the monitoring action will be invoked after possible
		546	message loss has been detected. No messages will be lost "in between"
		547	(after the first lost message no further messages will be received by the
		548	port). After the monitoring action was invoked, further messages might get
		549	delivered again.
		550
		551	In the first form (callback), the callback is simply called with any
		552	number of C<@reason> elements (no @reason means that the port was deleted
		553	"normally"). Note also that I<< the callback B<must> never die >>, so use
		554	C<eval> if unsure.
		555
		556	In the second form (another port given), the other port (C<$rcvport>)
		557	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
		558	"normal" kils nothing happens, while under all other conditions, the other
		559	port is killed with the same reason.
		560
		561	The third form (kill self) is the same as the second form, except that
		562	C<$rvport> defaults to C<$SELF>.
		563
		564	In the last form (message), a message of the form C<@msg, @reason> will be
		565	C<snd>.
		566
		567	As a rule of thumb, monitoring requests should always monitor a port from
		568	a local port (or callback). The reason is that kill messages might get
		569	lost, just like any other message. Another less obvious reason is that
		570	even monitoring requests can get lost (for exmaple, when the connection
		571	to the other node goes down permanently). When monitoring a port locally
		572	these problems do not exist.
		573
		574	Example: call a given callback when C<$port> is killed.
		575
		576	mon $port, sub { warn "port died because of <@_>\n" };
		577
		578	Example: kill ourselves when C<$port> is killed abnormally.
		579
		580	mon $port;
		581
		582	Example: send us a restart message when another C<$port> is killed.
		583
		584	mon $port, $self => "restart";
		585
		586	=cut
		587
		588	sub mon {
		589	my ($noderef, $port) = split /#/, shift, 2;
		590
		591	my $node = $NODE{$noderef} \|\| add_node $noderef;
		592
		593	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
		594
		595	unless (ref $cb) {
		596	if (@_) {
		597	# send a kill info message
		598	my (@msg) = ($cb, @_);
		599	$cb = sub { snd @msg, @_ };
		600	} else {
		601	# simply kill other port
		602	my $port = $cb;
		603	$cb = sub { kil $port, @_ if @_ };
		604	}
		605	}
		606
		607	$node->monitor ($port, $cb);
		608
		609	defined wantarray
		610	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		611	}
		612
		613	=item $guard = mon_guard $port, $ref, $ref...
		614
		615	Monitors the given C<$port> and keeps the passed references. When the port
		616	is killed, the references will be freed.
		617
		618	Optionally returns a guard that will stop the monitoring.
		619
		620	This function is useful when you create e.g. timers or other watchers and
		621	want to free them when the port gets killed:
		622
		623	$port->rcv (start => sub {
		624	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		625	undef $timer if 0.9 < rand;
		626	});
		627	});
		628
		629	=cut
		630
		631	sub mon_guard {
		632	my ($port, @refs) = @_;
		633
		634	#TODO: mon-less form?
		635
		636	mon $port, sub { 0 && @refs }
		637	}
		638
		639	=item kil $port[, @reason]
		640
		641	Kill the specified port with the given C<@reason>.
		642
		643	If no C<@reason> is specified, then the port is killed "normally" (linked
		644	ports will not be kileld, or even notified).
		645
		646	Otherwise, linked ports get killed with the same reason (second form of
		647	C<mon>, see below).
		648
		649	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		650	will be reported as reason C<< die => $@ >>.
		651
		652	Transport/communication errors are reported as C<< transport_error =>
		653	$message >>.
		654
		655	=cut
		656
		657	=item $port = spawn $node, $initfunc[, @initdata]
		658
		659	Creates a port on the node C<$node> (which can also be a port ID, in which
		660	case it's the node where that port resides).
		661
		662	The port ID of the newly created port is return immediately, and it is
		663	permissible to immediately start sending messages or monitor the port.
		664
		665	After the port has been created, the init function is
		666	called. This function must be a fully-qualified function name
		667	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		668	program, use C<::name>.
		669
		670	If the function doesn't exist, then the node tries to C<require>
		671	the package, then the package above the package and so on (e.g.
		672	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		673	exists or it runs out of package names.
		674
		675	The init function is then called with the newly-created port as context
		676	object (C<$SELF>) and the C<@initdata> values as arguments.
		677
		678	A common idiom is to pass your own port, monitor the spawned port, and
		679	in the init function, monitor the original port. This two-way monitoring
		680	ensures that both ports get cleaned up when there is a problem.
		681
		682	Example: spawn a chat server port on C<$othernode>.
		683
		684	# this node, executed from within a port context:
		685	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		686	mon $server;
		687
		688	# init function on C<$othernode>
		689	sub connect {
		690	my ($srcport) = @_;
		691
		692	mon $srcport;
		693
		694	rcv $SELF, sub {
		695	...
		696	};
		697	}
		698
		699	=cut
		700
		701	sub _spawn {
		702	my $port = shift;
		703	my $init = shift;
		704
		705	local $SELF = "$NODE#$port";
		706	eval {
		707	&{ load_func $init }
		708	};
		709	_self_die if $@;
		710	}
		711
		712	sub spawn(@) {
		713	my ($noderef, undef) = split /#/, shift, 2;
		714
		715	my $id = "$RUNIQ." . $ID++;
		716
		717	$_[0] =~ /::/
		718	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		719
		720	($NODE{$noderef} \|\| add_node $noderef)
		721	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		722
		723	"$noderef#$id"
365	}	724	}
366		725
367	=back	726	=back
368		727
369	=head1 NODE MESSAGES	728	=head1 NODE MESSAGES
…		…
371	Nodes understand the following messages sent to them. Many of them take	730	Nodes understand the following messages sent to them. Many of them take
372	arguments called C<@reply>, which will simply be used to compose a reply	731	arguments called C<@reply>, which will simply be used to compose a reply
373	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	732	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
374	the remaining arguments are simply the message data.	733	the remaining arguments are simply the message data.
375		734
		735	While other messages exist, they are not public and subject to change.
		736
376	=over 4	737	=over 4
377		738
378	=cut	739	=cut
379		740
380	#############################################################################	741	=item lookup => $name, @reply
381	# self node code
382		742
383	sub _new_port($) {	743	Replies with the port ID of the specified well-known port, or C<undef>.
384	my ($name) = @_;
385		744
386	my ($noderef, $portname) = split /#/, $name;	745	=item devnull => ...
387		746
388	$PORT{$name} =	747	Generic data sink/CPU heat conversion.
389	$PORT{$portname} = {
390	names => [$name, $portname],
391	};
392	}
393
394	$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE;
395	_new_port "";
396		748
397	=item relay => $port, @msg	749	=item relay => $port, @msg
398		750
399	Simply forwards the message to the given port.	751	Simply forwards the message to the given port.
400
401	=cut
402
403	rcv "", relay => \&snd;
404		752
405	=item eval => $string[ @reply]	753	=item eval => $string[ @reply]
406		754
407	Evaluates the given string. If C<@reply> is given, then a message of the	755	Evaluates the given string. If C<@reply> is given, then a message of the
408	form C<@reply, $@, @evalres> is sent.	756	form C<@reply, $@, @evalres> is sent.
409		757
410	Example: crash another node.	758	Example: crash another node.
411		759
412	snd $othernode, eval => "exit";	760	snd $othernode, eval => "exit";
413		761
414	=cut
415
416	rcv "", eval => sub {
417	my (undef, $string, @reply) = @_;
418	my @res = eval $string;
419	snd @reply, "$@", @res if @reply;
420	};
421
422	=item time => @reply	762	=item time => @reply
423		763
424	Replies the the current node time to C<@reply>.	764	Replies the the current node time to C<@reply>.
425		765
426	Example: tell the current node to send the current time to C<$myport> in a	766	Example: tell the current node to send the current time to C<$myport> in a
427	C<timereply> message.	767	C<timereply> message.
428		768
429	snd $NODE, time => $myport, timereply => 1, 2;	769	snd $NODE, time => $myport, timereply => 1, 2;
430	# => snd $myport, timereply => 1, 2, <time>	770	# => snd $myport, timereply => 1, 2, <time>
431		771
432	=cut	772	=back
433		773
434	rcv "", time => sub { shift; snd @_, AE::time };	774	=head1 AnyEvent::MP vs. Distributed Erlang
		775
		776	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
		777	== aemp node, Erlang process == aemp port), so many of the documents and
		778	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		779	sample:
		780
		781	http://www.Erlang.se/doc/programming_rules.shtml
		782	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		783	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		784	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		785
		786	Despite the similarities, there are also some important differences:
		787
		788	=over 4
		789
		790	=item * Node references contain the recipe on how to contact them.
		791
		792	Erlang relies on special naming and DNS to work everywhere in the
		793	same way. AEMP relies on each node knowing it's own address(es), with
		794	convenience functionality.
		795
		796	This means that AEMP requires a less tightly controlled environment at the
		797	cost of longer node references and a slightly higher management overhead.
		798
		799	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		800
		801	Erlang uses processes that selctively receive messages, and therefore
		802	needs a queue. AEMP is event based, queuing messages would serve no useful
		803	purpose.
		804
		805	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
		806
		807	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		808
		809	Sending messages in Erlang is synchronous and blocks the process. AEMP
		810	sends are immediate, connection establishment is handled in the
		811	background.
		812
		813	=item * Erlang can silently lose messages, AEMP cannot.
		814
		815	Erlang makes few guarantees on messages delivery - messages can get lost
		816	without any of the processes realising it (i.e. you send messages a, b,
		817	and c, and the other side only receives messages a and c).
		818
		819	AEMP guarantees correct ordering, and the guarantee that there are no
		820	holes in the message sequence.
		821
		822	=item * In Erlang, processes can be declared dead and later be found to be
		823	alive.
		824
		825	In Erlang it can happen that a monitored process is declared dead and
		826	linked processes get killed, but later it turns out that the process is
		827	still alive - and can receive messages.
		828
		829	In AEMP, when port monitoring detects a port as dead, then that port will
		830	eventually be killed - it cannot happen that a node detects a port as dead
		831	and then later sends messages to it, finding it is still alive.
		832
		833	=item * Erlang can send messages to the wrong port, AEMP does not.
		834
		835	In Erlang it is quite possible that a node that restarts reuses a process
		836	ID known to other nodes for a completely different process, causing
		837	messages destined for that process to end up in an unrelated process.
		838
		839	AEMP never reuses port IDs, so old messages or old port IDs floating
		840	around in the network will not be sent to an unrelated port.
		841
		842	=item * Erlang uses unprotected connections, AEMP uses secure
		843	authentication and can use TLS.
		844
		845	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		846	securely authenticate nodes.
		847
		848	=item * The AEMP protocol is optimised for both text-based and binary
		849	communications.
		850
		851	The AEMP protocol, unlike the Erlang protocol, supports both
		852	language-independent text-only protocols (good for debugging) and binary,
		853	language-specific serialisers (e.g. Storable).
		854
		855	It has also been carefully designed to be implementable in other languages
		856	with a minimum of work while gracefully degrading fucntionality to make the
		857	protocol simple.
		858
		859	=item * AEMP has more flexible monitoring options than Erlang.
		860
		861	In Erlang, you can chose to receive I<all> exit signals as messages
		862	or I<none>, there is no in-between, so monitoring single processes is
		863	difficult to implement. Monitoring in AEMP is more flexible than in
		864	Erlang, as one can choose between automatic kill, exit message or callback
		865	on a per-process basis.
		866
		867	=item * Erlang tries to hide remote/local connections, AEMP does not.
		868
		869	Monitoring in Erlang is not an indicator of process death/crashes,
		870	as linking is (except linking is unreliable in Erlang).
		871
		872	In AEMP, you don't "look up" registered port names or send to named ports
		873	that might or might not be persistent. Instead, you normally spawn a port
		874	on the remote node. The init function monitors the you, and you monitor
		875	the remote port. Since both monitors are local to the node, they are much
		876	more reliable.
		877
		878	This also saves round-trips and avoids sending messages to the wrong port
		879	(hard to do in Erlang).
		880
		881	=back
		882
		883	=head1 RATIONALE
		884
		885	=over 4
		886
		887	=item Why strings for ports and noderefs, why not objects?
		888
		889	We considered "objects", but found that the actual number of methods
		890	thatc an be called are very low. Since port IDs and noderefs travel over
		891	the network frequently, the serialising/deserialising would add lots of
		892	overhead, as well as having to keep a proxy object.
		893
		894	Strings can easily be printed, easily serialised etc. and need no special
		895	procedures to be "valid".
		896
		897	And a a miniport consists of a single closure stored in a global hash - it
		898	can't become much cheaper.
		899
		900	=item Why favour JSON, why not real serialising format such as Storable?
		901
		902	In fact, any AnyEvent::MP node will happily accept Storable as framing
		903	format, but currently there is no way to make a node use Storable by
		904	default.
		905
		906	The default framing protocol is JSON because a) JSON::XS is many times
		907	faster for small messages and b) most importantly, after years of
		908	experience we found that object serialisation is causing more problems
		909	than it gains: Just like function calls, objects simply do not travel
		910	easily over the network, mostly because they will always be a copy, so you
		911	always have to re-think your design.
		912
		913	Keeping your messages simple, concentrating on data structures rather than
		914	objects, will keep your messages clean, tidy and efficient.
435		915
436	=back	916	=back
437		917
438	=head1 SEE ALSO	918	=head1 SEE ALSO
439		919

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Revision 1.49 by root, Thu Aug 13 15:29:58 2009 UTC