[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 1.44 by root, Wed Aug 12 21:39:58 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	# ports are message endpoints
		16
		17	# sending messages
12	snd $port, type => data...;	18	snd $port, type => data...;
		19	snd $port, @msg;
		20	snd @msg_with_first_element_being_a_port;
13		21
		22	# miniports
		23	my $miniport = port { my @msg = @_; 0 };
		24
		25	# full ports
		26	my $port = port;
14	rcv $port, smartmatch => $cb->($port, @msg);	27	rcv $port, smartmatch => $cb->(@msg);
15
16	# examples:
17	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
18	rcv $port1, pong => sub { warn "pong received\n" };	29	rcv $port, pong => sub { warn "pong received\n"; 0 };
19	snd $port2, ping => $port1;	30
		31	# remote ports
		32	my $port = spawn $node, $initfunc, @initdata;
20		33
21	# more, smarter, matches (_any_ is exported by this module)	34	# more, smarter, matches (_any_ is exported by this module)
22	rcv $port, [child_died => $pid] => sub { ...	35	rcv $port, [child_died => $pid] => sub { ...
23	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
24		37
		38	# monitoring
		39	mon $port, $cb->(@msg) # callback is invoked on death
		40	mon $port, $otherport # kill otherport on abnormal death
		41	mon $port, $otherport, @msg # send message on death
		42
25	=head1 DESCRIPTION	43	=head1 DESCRIPTION
26		44
27	This module (-family) implements a simple message passing framework.	45	This module (-family) implements a simple message passing framework.
28		46
29	Despite its simplicity, you can securely message other processes running	47	Despite its simplicity, you can securely message other processes running
30	on the same or other hosts.	48	on the same or other hosts.
31		49
		50	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		51	manual page.
		52
		53	At the moment, this module family is severly broken and underdocumented,
		54	so do not use. This was uploaded mainly to reserve the CPAN namespace -
		55	stay tuned! The basic API should be finished, however.
		56
32	=head1 CONCEPTS	57	=head1 CONCEPTS
33		58
34	=over 4	59	=over 4
35		60
36	=item port	61	=item port
37		62
38	A port is something you can send messages to with the C<snd> function, and	63	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	64
40	messages they match, messages will not be queued.	65	Some ports allow you to register C<rcv> handlers that can match specific
		66	messages. All C<rcv> handlers will receive messages they match, messages
		67	will not be queued.
41		68
42	=item port id - C<noderef#portname>	69	=item port id - C<noderef#portname>
43		70
44	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	71	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).	72	separator, and a port name (a printable string of unspecified format). An
		73	exception is the the node port, whose ID is identical to its node
		74	reference.
46		75
47	=item node	76	=item node
48		77
49	A node is a single process containing at least one port - the node	78	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,	79	port. You can send messages to node ports to find existing ports or to
51	among other things.	80	create new ports, among other things.
52		81
53	Initially, nodes are either private (single-process only) or hidden	82	Nodes are either private (single-process only), slaves (connected to a
54	(connected to a master node only). Only when they epxlicitly "become	83	master node only) or public nodes (connectable from unrelated nodes).
55	public" can you send them messages from unrelated other nodes.
56		84
57	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>	85	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
58		86
59	A noderef is a string that either uniquely identifies a given node (for	87	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	88	private and slave nodes), or contains a recipe on how to reach a given
61	node (for public nodes).	89	node (for public nodes).
62		90
		91	This recipe is simply a comma-separated list of C<address:port> pairs (for
		92	TCP/IP, other protocols might look different).
		93
		94	Node references come in two flavours: resolved (containing only numerical
		95	addresses) or unresolved (where hostnames are used instead of addresses).
		96
		97	Before using an unresolved node reference in a message you first have to
		98	resolve it.
		99
63	=back	100	=back
64		101
65	=head1 VARIABLES/FUNCTIONS	102	=head1 VARIABLES/FUNCTIONS
66		103
67	=over 4	104	=over 4
68		105
69	=cut	106	=cut
70		107
71	package AnyEvent::MP;	108	package AnyEvent::MP;
72		109
73	use AnyEvent::MP::Util ();
74	use AnyEvent::MP::Node;	110	use AnyEvent::MP::Kernel;
75	use AnyEvent::MP::Transport;
76		111
77	use utf8;
78	use common::sense;	112	use common::sense;
79		113
80	use Carp ();	114	use Carp ();
81		115
82	use AE ();	116	use AE ();
83		117
84	use base "Exporter";	118	use base "Exporter";
85		119
86	our $VERSION = '0.0';	120	our $VERSION = $AnyEvent::MP::Kernel::VERSION;
87	our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_);
88		121
89	our $DEFAULT_SECRET;	122	our @EXPORT = qw(
90	our $DEFAULT_PORT = "4040";	123	NODE $NODE *SELF node_of _any_
		124	resolve_node initialise_node
		125	snd rcv mon kil reg psub spawn
		126	port
		127	);
91		128
92	our $CONNECT_INTERVAL = 5; # new connect every 5s, at least	129	our $SELF;
93	our $CONNECT_TIMEOUT = 30; # includes handshake
94		130
95	sub default_secret {	131	sub _self_die() {
96	unless (defined $DEFAULT_SECRET) {	132	my $msg = $@;
97	if (open my $fh, "<$ENV{HOME}/.aemp-secret") {	133	$msg =~ s/\n+$// unless ref $msg;
98	sysread $fh, $DEFAULT_SECRET, -s $fh;	134	kil $SELF, die => $msg;
99	} else {
100	$DEFAULT_SECRET = AnyEvent::MP::Util::nonce 32;
101	}
102	}
103
104	$DEFAULT_SECRET
105	}	135	}
106		136
107	=item NODE / $NODE	137	=item $thisnode = NODE / $NODE
108		138
109	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	139	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	140	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.	141	to C<become_public> or C<become_slave>, after which all local port
		142	identifiers become invalid.
112		143
113	=cut	144	=item $noderef = node_of $port
114		145
115	our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie	146	Extracts and returns the noderef from a portid or a noderef.
116	our $PUBLIC = 0;
117	our $NODE;
118	our $PORT;
119		147
120	our %NODE; # node id to transport mapping, or "undef", for local node	148	=item initialise_node $noderef, $seednode, $seednode...
121	our %PORT; # local ports
122	our %LISTENER; # local transports
123		149
124	sub NODE() { $NODE }	150	=item initialise_node "slave/", $master, $master...
125		151
126	{	152	Before a node can talk to other nodes on the network it has to initialise
127	use POSIX ();	153	itself - the minimum a node needs to know is it's own name, and optionally
128	my $nodename = (POSIX::uname)[1];	154	it should know the noderefs of some other nodes in the network.
129	$NODE = "$$\@$nodename";
130	}
131		155
132	sub _ANY_() { 1 }	156	This function initialises a node - it must be called exactly once (or
133	sub _any_() { \&_ANY_ }	157	never) before calling other AnyEvent::MP functions.
134		158
135	sub add_node {	159	All arguments are noderefs, which can be either resolved or unresolved.
136	my ($noderef) = @_;
137		160
138	return $NODE{$noderef}	161	There are two types of networked nodes, public nodes and slave nodes:
139	if exists $NODE{$noderef};
140		162
141	for (split /,/, $noderef) {	163	=over 4
142	return $NODE{$noderef} = $NODE{$_}
143	if exists $NODE{$_};
144	}
145		164
146	# for indirect sends, use a different class	165	=item public nodes
147	my $node = new AnyEvent::MP::Node::Direct $noderef;
148		166
149	$NODE{$_} = $node	167	For public nodes, C<$noderef> must either be a (possibly unresolved)
150	for $noderef, split /,/, $noderef;	168	noderef, in which case it will be resolved, or C<undef> (or missing), in
		169	which case the noderef will be guessed.
151		170
152	$node	171	Afterwards, the node will bind itself on all endpoints and try to connect
153	}	172	to all additional C<$seednodes> that are specified. Seednodes are optional
		173	and can be used to quickly bootstrap the node into an existing network.
154		174
		175	=item slave nodes
		176
		177	When the C<$noderef> is the special string C<slave/>, then the node will
		178	become a slave node. Slave nodes cannot be contacted from outside and will
		179	route most of their traffic to the master node that they attach to.
		180
		181	At least one additional noderef is required: The node will try to connect
		182	to all of them and will become a slave attached to the first node it can
		183	successfully connect to.
		184
		185	=back
		186
		187	This function will block until all nodes have been resolved and, for slave
		188	nodes, until it has successfully established a connection to a master
		189	server.
		190
		191	Example: become a public node listening on the default node.
		192
		193	initialise_node;
		194
		195	Example: become a public node, and try to contact some well-known master
		196	servers to become part of the network.
		197
		198	initialise_node undef, "master1", "master2";
		199
		200	Example: become a public node listening on port C<4041>.
		201
		202	initialise_node 4041;
		203
		204	Example: become a public node, only visible on localhost port 4044.
		205
		206	initialise_node "locahost:4044";
		207
		208	Example: become a slave node to any of the specified master servers.
		209
		210	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
		211
		212	=item $cv = resolve_node $noderef
		213
		214	Takes an unresolved node reference that may contain hostnames and
		215	abbreviated IDs, resolves all of them and returns a resolved node
		216	reference.
		217
		218	In addition to C<address:port> pairs allowed in resolved noderefs, the
		219	following forms are supported:
		220
		221	=over 4
		222
		223	=item the empty string
		224
		225	An empty-string component gets resolved as if the default port (4040) was
		226	specified.
		227
		228	=item naked port numbers (e.g. C<1234>)
		229
		230	These are resolved by prepending the local nodename and a colon, to be
		231	further resolved.
		232
		233	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
		234
		235	These are resolved by using AnyEvent::DNS to resolve them, optionally
		236	looking up SRV records for the C<aemp=4040> port, if no port was
		237	specified.
		238
		239	=back
		240
		241	=item $SELF
		242
		243	Contains the current port id while executing C<rcv> callbacks or C<psub>
		244	blocks.
		245
		246	=item SELF, %SELF, @SELF...
		247
		248	Due to some quirks in how perl exports variables, it is impossible to
		249	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		250	module, but only C<$SELF> is currently used.
		251
155	=item snd $portid, type => @data	252	=item snd $port, type => @data
156		253
157	=item snd $portid, @msg	254	=item snd $port, @msg
158		255
159	Send the given message to the given port ID, which can identify either a	256	Send the given message to the given port ID, which can identify either
160	local or a remote port.	257	a local or a remote port, and can be either a string or soemthignt hat
		258	stringifies a sa port ID (such as a port object :).
161		259
162	While the message can be about anything, it is highly recommended to use	260	While the message can be about anything, it is highly recommended to use a
163	a constant string as first element.	261	string as first element (a portid, or some word that indicates a request
		262	type etc.).
164		263
165	The message data effectively becomes read-only after a call to this	264	The message data effectively becomes read-only after a call to this
166	function: modifying any argument is not allowed and can cause many	265	function: modifying any argument is not allowed and can cause many
167	problems.	266	problems.
168		267
…		…
170	JSON is used, then only strings, numbers and arrays and hashes consisting	269	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	270	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	271	that Storable can serialise and deserialise is allowed, and for the local
173	node, anything can be passed.	272	node, anything can be passed.
174		273
175	=cut	274	=item $local_port = port
176		275
177	sub snd(@) {	276	Create a new local port object that can be used either as a pattern
178	my ($noderef, $port) = split /#/, shift, 2;	277	matching port ("full port") or a single-callback port ("miniport"),
		278	depending on how C<rcv> callbacks are bound to the object.
179		279
180	add_node $noderef	280	=item $port = port { my @msg = @_; $finished }
181	unless exists $NODE{$noderef};
182		281
183	$NODE{$noderef}->send (["$port", [@_]]);	282	Creates a "miniport", that is, a very lightweight port without any pattern
		283	matching behind it, and returns its ID. Semantically the same as creating
		284	a port and calling C<rcv $port, $callback> on it.
		285
		286	The block will be called for every message received on the port. When the
		287	callback returns a true value its job is considered "done" and the port
		288	will be destroyed. Otherwise it will stay alive.
		289
		290	The message will be passed as-is, no extra argument (i.e. no port id) will
		291	be passed to the callback.
		292
		293	If you need the local port id in the callback, this works nicely:
		294
		295	my $port; $port = port {
		296	snd $otherport, reply => $port;
		297	};
		298
		299	=cut
		300
		301	sub rcv($@);
		302
		303	sub port(;&) {
		304	my $id = "$UNIQ." . $ID++;
		305	my $port = "$NODE#$id";
		306
		307	if (@_) {
		308	rcv $port, shift;
		309	} else {
		310	$PORT{$id} = sub { }; # nop
		311	}
		312
		313	$port
184	}	314	}
185		315
		316	=item reg $port, $name
		317
		318	=item reg $name
		319
		320	Registers the given port (or C<$SELF><<< if missing) under the name
		321	C<$name>. If the name already exists it is replaced.
		322
		323	A port can only be registered under one well known name.
		324
		325	A port automatically becomes unregistered when it is killed.
		326
		327	=cut
		328
		329	sub reg(@) {
		330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		331
		332	$REG{$_[0]} = $port;
		333	}
		334
186	=item rcv $portid, type => $callback->(@msg)	335	=item rcv $port, $callback->(@msg)
187		336
		337	Replaces the callback on the specified miniport (after converting it to
		338	one if required).
		339
		340	=item rcv $port, tagstring => $callback->(@msg), ...
		341
188	=item rcv $portid, $smartmatch => $callback->(@msg)	342	=item rcv $port, $smartmatch => $callback->(@msg), ...
189		343
190	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
191		345
192	Register a callback on the port identified by C<$portid>, which I<must> be	346	Register callbacks to be called on matching messages on the given full
193	a local port.	347	port (after converting it to one if required) and return the port.
194		348
195	The callback has to return a true value when its work is done, after	349	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	350	which is will be removed, or a false value in which case it will stay
197	registered.	351	registered.
198		352
		353	The global C<$SELF> (exported by this module) contains C<$port> while
		354	executing the callback.
		355
		356	Runtime errors during callback execution will result in the port being
		357	C<kil>ed.
		358
199	If the match is an array reference, then it will be matched against the	359	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	360	first elements of the message, otherwise only the first element is being
201	matched.	361	matched.
202		362
203	Any element in the match that is specified as C<_any_> (a function	363	Any element in the match that is specified as C<_any_> (a function
…		…
205		365
206	While not required, it is highly recommended that the first matching	366	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	367	element is a string identifying the message. The one-string-only match is
208	also the most efficient match (by far).	368	also the most efficient match (by far).
209		369
		370	Example: create a port and bind receivers on it in one go.
		371
		372	my $port = rcv port,
		373	msg1 => sub { ...; 0 },
		374	msg2 => sub { ...; 0 },
		375	;
		376
		377	Example: create a port, bind receivers and send it in a message elsewhere
		378	in one go:
		379
		380	snd $otherport, reply =>
		381	rcv port,
		382	msg1 => sub { ...; 0 },
		383	...
		384	;
		385
210	=cut	386	=cut
211		387
212	sub rcv($@) {	388	sub rcv($@) {
213	my ($port, $match, $cb) = @_;	389	my $port = shift;
214
215	my $port = $PORT{$port}
216	or do {
217	my ($noderef, $lport) = split /#/, $port;	390	my ($noderef, $portid) = split /#/, $port, 2;
218	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	391
		392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
219	or Carp::croak "$port: can only rcv on local ports";	393	or Carp::croak "$port: rcv can only be called on local ports, caught";
220		394
221	$PORT{$lport}	395	if (@_ == 1) {
222	or Carp::croak "$port: port does not exist";	396	my $cb = shift;
		397	delete $PORT_DATA{$portid};
		398	$PORT{$portid} = sub {
		399	local $SELF = $port;
		400	eval {
223		401	&$cb
224	$PORT{$port} = $PORT{$lport} # also return	402	and kil $port;
		403	};
		404	_self_die if $@;
225	};	405	};
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 {	406	} else {
235	push @{ $port->{any} }, [$cb, $match];	407	my $self = $PORT_DATA{$portid} \|\|= do {
236	}	408	my $self = bless {
237	}	409	id => $port,
		410	}, "AnyEvent::MP::Port";
238		411
239	sub _inject {	412	$PORT{$portid} = sub {
240	my ($port, $msg) = @{+shift};	413	local $SELF = $port;
241		414
242	$port = $PORT{$port}	415	eval {
243	or return;	416	for (@{ $self->{rc0}{$_[0]} }) {
244
245	@_ = @$msg;
246
247	for (@{ $port->{rc0}{$msg->[0]} }) {
248	$_ && &{$_->[0]}	417	$_ && &{$_->[0]}
249	&& undef $_;	418	&& 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	];	419	}
		420
		421	for (@{ $self->{rcv}{$_[0]} }) {
		422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		423	&& &{$_->[0]}
		424	&& undef $_;
		425	}
		426
		427	for (@{ $self->{any} }) {
		428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		429	&& &{$_->[0]}
		430	&& undef $_;
		431	}
298	}	432	};
299	$cv->end;	433	_self_die if $@;
300	};	434	};
301		435
302	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;	436	$self
303	#	437	};
304	# for (@ipv4) {	438
305	# push @res, [	439	"AnyEvent::MP::Port" eq ref $self
306	# $pri,	440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
307	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,	441
308	# ];	442	while (@_) {
309	# }	443	my ($match, $cb) = splice @_, 0, 2;
		444
		445	if (!ref $match) {
		446	push @{ $self->{rc0}{$match} }, [$cb];
		447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		448	my ($type, @match) = @$match;
		449	@match
		450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
310	} else {	452	} else {
311	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	453	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	}	454	}
325	}	455	}
326	}	456	}
327		457
328	$cv->end;	458	$port
329
330	$cv
331	}	459	}
332		460
333	sub become_public {	461	=item $closure = psub { BLOCK }
334	return if $PUBLIC;
335		462
336	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	463	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
337	my @args = @_;	464	closure is executed, sets up the environment in the same way as in C<rcv>
		465	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
338		466
339	$NODE = (normalise_noderef $noderef)->recv;	467	This is useful when you register callbacks from C<rcv> callbacks:
340		468
341	for my $t (split /,/, $NODE) {	469	rcv delayed_reply => sub {
342	$NODE{$t} = $NODE{""};	470	my ($delay, @reply) = @_;
343		471	my $timer = AE::timer $delay, 0, psub {
344	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	472	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	;	473	};
		474	};
		475
		476	=cut
		477
		478	sub psub(&) {
		479	my $cb = shift;
		480
		481	my $port = $SELF
		482	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		483
		484	sub {
		485	local $SELF = $port;
		486
		487	if (wantarray) {
		488	my @res = eval { &$cb };
		489	_self_die if $@;
		490	@res
		491	} else {
		492	my $res = eval { &$cb };
		493	_self_die if $@;
		494	$res
		495	}
362	}	496	}
		497	}
363		498
364	$PUBLIC = 1;	499	=item $guard = mon $port, $cb->(@reason)
		500
		501	=item $guard = mon $port, $rcvport
		502
		503	=item $guard = mon $port
		504
		505	=item $guard = mon $port, $rcvport, @msg
		506
		507	Monitor the given port and do something when the port is killed or
		508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
		510
		511	C<mon> effectively guarantees that, in the absence of hardware failures,
		512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
		518
		519	In the first form (callback), the callback is simply called with any
		520	number of C<@reason> elements (no @reason means that the port was deleted
		521	"normally"). Note also that I<< the callback B<must> never die >>, so use
		522	C<eval> if unsure.
		523
		524	In the second form (another port given), the other port (C<$rcvport>)
		525	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
		526	"normal" kils nothing happens, while under all other conditions, the other
		527	port is killed with the same reason.
		528
		529	The third form (kill self) is the same as the second form, except that
		530	C<$rvport> defaults to C<$SELF>.
		531
		532	In the last form (message), a message of the form C<@msg, @reason> will be
		533	C<snd>.
		534
		535	As a rule of thumb, monitoring requests should always monitor a port from
		536	a local port (or callback). The reason is that kill messages might get
		537	lost, just like any other message. Another less obvious reason is that
		538	even monitoring requests can get lost (for exmaple, when the connection
		539	to the other node goes down permanently). When monitoring a port locally
		540	these problems do not exist.
		541
		542	Example: call a given callback when C<$port> is killed.
		543
		544	mon $port, sub { warn "port died because of <@_>\n" };
		545
		546	Example: kill ourselves when C<$port> is killed abnormally.
		547
		548	mon $port;
		549
		550	Example: send us a restart message when another C<$port> is killed.
		551
		552	mon $port, $self => "restart";
		553
		554	=cut
		555
		556	sub mon {
		557	my ($noderef, $port) = split /#/, shift, 2;
		558
		559	my $node = $NODE{$noderef} \|\| add_node $noderef;
		560
		561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
		562
		563	unless (ref $cb) {
		564	if (@_) {
		565	# send a kill info message
		566	my (@msg) = ($cb, @_);
		567	$cb = sub { snd @msg, @_ };
		568	} else {
		569	# simply kill other port
		570	my $port = $cb;
		571	$cb = sub { kil $port, @_ if @_ };
		572	}
		573	}
		574
		575	$node->monitor ($port, $cb);
		576
		577	defined wantarray
		578	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		579	}
		580
		581	=item $guard = mon_guard $port, $ref, $ref...
		582
		583	Monitors the given C<$port> and keeps the passed references. When the port
		584	is killed, the references will be freed.
		585
		586	Optionally returns a guard that will stop the monitoring.
		587
		588	This function is useful when you create e.g. timers or other watchers and
		589	want to free them when the port gets killed:
		590
		591	$port->rcv (start => sub {
		592	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		593	undef $timer if 0.9 < rand;
		594	});
		595	});
		596
		597	=cut
		598
		599	sub mon_guard {
		600	my ($port, @refs) = @_;
		601
		602	#TODO: mon-less form?
		603
		604	mon $port, sub { 0 && @refs }
		605	}
		606
		607	=item kil $port[, @reason]
		608
		609	Kill the specified port with the given C<@reason>.
		610
		611	If no C<@reason> is specified, then the port is killed "normally" (linked
		612	ports will not be kileld, or even notified).
		613
		614	Otherwise, linked ports get killed with the same reason (second form of
		615	C<mon>, see below).
		616
		617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		618	will be reported as reason C<< die => $@ >>.
		619
		620	Transport/communication errors are reported as C<< transport_error =>
		621	$message >>.
		622
		623	=cut
		624
		625	=item $port = spawn $node, $initfunc[, @initdata]
		626
		627	Creates a port on the node C<$node> (which can also be a port ID, in which
		628	case it's the node where that port resides).
		629
		630	The port ID of the newly created port is return immediately, and it is
		631	permissible to immediately start sending messages or monitor the port.
		632
		633	After the port has been created, the init function is
		634	called. This function must be a fully-qualified function name
		635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		636	program, use C<::name>.
		637
		638	If the function doesn't exist, then the node tries to C<require>
		639	the package, then the package above the package and so on (e.g.
		640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		641	exists or it runs out of package names.
		642
		643	The init function is then called with the newly-created port as context
		644	object (C<$SELF>) and the C<@initdata> values as arguments.
		645
		646	A common idiom is to pass your own port, monitor the spawned port, and
		647	in the init function, monitor the original port. This two-way monitoring
		648	ensures that both ports get cleaned up when there is a problem.
		649
		650	Example: spawn a chat server port on C<$othernode>.
		651
		652	# this node, executed from within a port context:
		653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		654	mon $server;
		655
		656	# init function on C<$othernode>
		657	sub connect {
		658	my ($srcport) = @_;
		659
		660	mon $srcport;
		661
		662	rcv $SELF, sub {
		663	...
		664	};
		665	}
		666
		667	=cut
		668
		669	sub _spawn {
		670	my $port = shift;
		671	my $init = shift;
		672
		673	local $SELF = "$NODE#$port";
		674	eval {
		675	&{ load_func $init }
		676	};
		677	_self_die if $@;
		678	}
		679
		680	sub spawn(@) {
		681	my ($noderef, undef) = split /#/, shift, 2;
		682
		683	my $id = "$RUNIQ." . $ID++;
		684
		685	$_[0] =~ /::/
		686	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		687
		688	($NODE{$noderef} \|\| add_node $noderef)
		689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		690
		691	"$noderef#$id"
365	}	692	}
366		693
367	=back	694	=back
368		695
369	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
…		…
371	Nodes understand the following messages sent to them. Many of them take	698	Nodes understand the following messages sent to them. Many of them take
372	arguments called C<@reply>, which will simply be used to compose a reply	699	arguments called C<@reply>, which will simply be used to compose a reply
373	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and	700	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
374	the remaining arguments are simply the message data.	701	the remaining arguments are simply the message data.
375		702
		703	While other messages exist, they are not public and subject to change.
		704
376	=over 4	705	=over 4
377		706
378	=cut	707	=cut
379		708
380	#############################################################################	709	=item lookup => $name, @reply
381	# self node code
382		710
383	sub _new_port($) {	711	Replies with the port ID of the specified well-known port, or C<undef>.
384	my ($name) = @_;
385		712
386	my ($noderef, $portname) = split /#/, $name;	713	=item devnull => ...
387		714
388	$PORT{$name} =	715	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		716
397	=item relay => $port, @msg	717	=item relay => $port, @msg
398		718
399	Simply forwards the message to the given port.	719	Simply forwards the message to the given port.
400
401	=cut
402
403	rcv "", relay => \&snd;
404		720
405	=item eval => $string[ @reply]	721	=item eval => $string[ @reply]
406		722
407	Evaluates the given string. If C<@reply> is given, then a message of the	723	Evaluates the given string. If C<@reply> is given, then a message of the
408	form C<@reply, $@, @evalres> is sent.	724	form C<@reply, $@, @evalres> is sent.
409		725
410	Example: crash another node.	726	Example: crash another node.
411		727
412	snd $othernode, eval => "exit";	728	snd $othernode, eval => "exit";
413		729
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	730	=item time => @reply
423		731
424	Replies the the current node time to C<@reply>.	732	Replies the the current node time to C<@reply>.
425		733
426	Example: tell the current node to send the current time to C<$myport> in a	734	Example: tell the current node to send the current time to C<$myport> in a
427	C<timereply> message.	735	C<timereply> message.
428		736
429	snd $NODE, time => $myport, timereply => 1, 2;	737	snd $NODE, time => $myport, timereply => 1, 2;
430	# => snd $myport, timereply => 1, 2, <time>	738	# => snd $myport, timereply => 1, 2, <time>
431		739
432	=cut	740	=back
433		741
434	rcv "", time => sub { shift; snd @_, AE::time };	742	=head1 AnyEvent::MP vs. Distributed Erlang
		743
		744	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
		745	== aemp node, Erlang process == aemp port), so many of the documents and
		746	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
		747	sample:
		748
		749	http://www.Erlang.se/doc/programming_rules.shtml
		750	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		751	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
		752	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		753
		754	Despite the similarities, there are also some important differences:
		755
		756	=over 4
		757
		758	=item * Node references contain the recipe on how to contact them.
		759
		760	Erlang relies on special naming and DNS to work everywhere in the
		761	same way. AEMP relies on each node knowing it's own address(es), with
		762	convenience functionality.
		763
		764	This means that AEMP requires a less tightly controlled environment at the
		765	cost of longer node references and a slightly higher management overhead.
		766
		767	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		768
		769	Erlang uses processes that selctively receive messages, and therefore
		770	needs a queue. AEMP is event based, queuing messages would serve no useful
		771	purpose.
		772
		773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
		774
		775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		776
		777	Sending messages in Erlang is synchronous and blocks the process. AEMP
		778	sends are immediate, connection establishment is handled in the
		779	background.
		780
		781	=item * Erlang can silently lose messages, AEMP cannot.
		782
		783	Erlang makes few guarantees on messages delivery - messages can get lost
		784	without any of the processes realising it (i.e. you send messages a, b,
		785	and c, and the other side only receives messages a and c).
		786
		787	AEMP guarantees correct ordering, and the guarantee that there are no
		788	holes in the message sequence.
		789
		790	=item * In Erlang, processes can be declared dead and later be found to be
		791	alive.
		792
		793	In Erlang it can happen that a monitored process is declared dead and
		794	linked processes get killed, but later it turns out that the process is
		795	still alive - and can receive messages.
		796
		797	In AEMP, when port monitoring detects a port as dead, then that port will
		798	eventually be killed - it cannot happen that a node detects a port as dead
		799	and then later sends messages to it, finding it is still alive.
		800
		801	=item * Erlang can send messages to the wrong port, AEMP does not.
		802
		803	In Erlang it is quite possible that a node that restarts reuses a process
		804	ID known to other nodes for a completely different process, causing
		805	messages destined for that process to end up in an unrelated process.
		806
		807	AEMP never reuses port IDs, so old messages or old port IDs floating
		808	around in the network will not be sent to an unrelated port.
		809
		810	=item * Erlang uses unprotected connections, AEMP uses secure
		811	authentication and can use TLS.
		812
		813	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		814	securely authenticate nodes.
		815
		816	=item * The AEMP protocol is optimised for both text-based and binary
		817	communications.
		818
		819	The AEMP protocol, unlike the Erlang protocol, supports both
		820	language-independent text-only protocols (good for debugging) and binary,
		821	language-specific serialisers (e.g. Storable).
		822
		823	It has also been carefully designed to be implementable in other languages
		824	with a minimum of work while gracefully degrading fucntionality to make the
		825	protocol simple.
		826
		827	=item * AEMP has more flexible monitoring options than Erlang.
		828
		829	In Erlang, you can chose to receive I<all> exit signals as messages
		830	or I<none>, there is no in-between, so monitoring single processes is
		831	difficult to implement. Monitoring in AEMP is more flexible than in
		832	Erlang, as one can choose between automatic kill, exit message or callback
		833	on a per-process basis.
		834
		835	=item * Erlang tries to hide remote/local connections, AEMP does not.
		836
		837	Monitoring in Erlang is not an indicator of process death/crashes,
		838	as linking is (except linking is unreliable in Erlang).
		839
		840	In AEMP, you don't "look up" registered port names or send to named ports
		841	that might or might not be persistent. Instead, you normally spawn a port
		842	on the remote node. The init function monitors the you, and you monitor
		843	the remote port. Since both monitors are local to the node, they are much
		844	more reliable.
		845
		846	This also saves round-trips and avoids sending messages to the wrong port
		847	(hard to do in Erlang).
435		848
436	=back	849	=back
437		850
438	=head1 SEE ALSO	851	=head1 SEE ALSO
439		852

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Revision 1.5 by root, Sat Aug 1 07:44:02 2009 UTC vs.
Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC