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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.4 by root, Sat Aug 1 07:36:30 2009 UTC vs.
Revision 1.30 by root, Tue Aug 4 23:35:51 2009 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	NODE # returns this node identifier
10	$NODE # contains this node identifier	9	$NODE # contains this node's noderef
		10	NODE # returns this node's noderef
		11	NODE $port # returns the noderef of the port
11		12
12	snd $port, type => data...;	13	snd $port, type => data...;
		14
		15	$SELF # receiving/own port id in rcv callbacks
13		16
14	rcv $port, smartmatch => $cb->($port, @msg);	17	rcv $port, smartmatch => $cb->($port, @msg);
15		18
16	# examples:	19	# examples:
17	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };
…		…
27	This module (-family) implements a simple message passing framework.	30	This module (-family) implements a simple message passing framework.
28		31
29	Despite its simplicity, you can securely message other processes running	32	Despite its simplicity, you can securely message other processes running
30	on the same or other hosts.	33	on the same or other hosts.
31		34
		35	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
		36	manual page.
		37
		38	At the moment, this module family is severly broken and underdocumented,
		39	so do not use. This was uploaded mainly to reserve the CPAN namespace -
		40	stay tuned! The basic API should be finished, however.
		41
32	=head1 CONCEPTS	42	=head1 CONCEPTS
33		43
34	=over 4	44	=over 4
35		45
36	=item port	46	=item port
37		47
38	A port is something you can send messages to with the C<snd> function, and	48	A port is something you can send messages to (with the C<snd> function).
39	you can register C<rcv> handlers with. All C<rcv> handlers will receive	49
40	messages they match, messages will not be queued.	50	Some ports allow you to register C<rcv> handlers that can match specific
		51	messages. All C<rcv> handlers will receive messages they match, messages
		52	will not be queued.
41		53
42	=item port id - C<noderef#portname>	54	=item port id - C<noderef#portname>
43		55
44	A port id is always the noderef, a hash-mark (C<#>) as separator, followed	56	A port id is normaly the concatenation of a noderef, a hash-mark (C<#>) as
45	by a port name (a printable string of unspecified format).	57	separator, and a port name (a printable string of unspecified format). An
		58	exception is the the node port, whose ID is identical to its node
		59	reference.
46		60
47	=item node	61	=item node
48		62
49	A node is a single process containing at least one port - the node	63	A node is a single process containing at least one port - the node
50	port. You can send messages to node ports to let them create new ports,	64	port. You can send messages to node ports to find existing ports or to
51	among other things.	65	create new ports, among other things.
52		66
53	Initially, nodes are either private (single-process only) or hidden	67	Nodes are either private (single-process only), slaves (connected to a
54	(connected to a master node only). Only when they epxlicitly "become	68	master node only) or public nodes (connectable from unrelated nodes).
55	public" can you send them messages from unrelated other nodes.
56		69
57	=item noderef - C<host:port,host:port...>, C<id@noderef, C<id>	70	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
58		71
59	A noderef is a string that either uniquely identifies a given node (for	72	A node reference is a string that either simply identifies the node (for
60	private and hidden nodes), or contains a recipe on how to reach a given	73	private and slave nodes), or contains a recipe on how to reach a given
61	node (for public nodes).	74	node (for public nodes).
62		75
		76	This recipe is simply a comma-separated list of C<address:port> pairs (for
		77	TCP/IP, other protocols might look different).
		78
		79	Node references come in two flavours: resolved (containing only numerical
		80	addresses) or unresolved (where hostnames are used instead of addresses).
		81
		82	Before using an unresolved node reference in a message you first have to
		83	resolve it.
		84
63	=back	85	=back
64		86
65	=head1 VARIABLES/FUNCTIONS	87	=head1 VARIABLES/FUNCTIONS
66		88
67	=over 4	89	=over 4
68		90
69	=cut	91	=cut
70		92
71	package AnyEvent::MP;	93	package AnyEvent::MP;
72		94
73	use AnyEvent::MP::Util ();
74	use AnyEvent::MP::Node;	95	use AnyEvent::MP::Base;
75	use AnyEvent::MP::Transport;
76		96
77	use utf8;
78	use common::sense;	97	use common::sense;
79		98
80	use Carp ();	99	use Carp ();
81		100
82	use AE ();	101	use AE ();
83		102
84	use base "Exporter";	103	use base "Exporter";
85		104
86	our $VERSION = '0.0';	105	our $VERSION = '0.1';
87	our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_);	106	our @EXPORT = qw(
		107	NODE $NODE *SELF node_of _any_
		108	resolve_node
		109	become_slave become_public
		110	snd rcv mon kil reg psub
		111	port
		112	);
88		113
89	our $DEFAULT_SECRET;	114	our $SELF;
90	our $DEFAULT_PORT = "4040";
91		115
92	our $CONNECT_INTERVAL = 5; # new connect every 5s, at least	116	sub _self_die() {
93	our $CONNECT_TIMEOUT = 30; # includes handshake	117	my $msg = $@;
94		118	$msg =~ s/\n+$// unless ref $msg;
95	sub default_secret {	119	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	}	120	}
106		121
107	=item NODE / $NODE	122	=item $thisnode = NODE / $NODE
108		123
109	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	124	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	125	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.	126	to C<become_public> or C<become_slave>, after which all local port
		127	identifiers become invalid.
112		128
113	=cut	129	=item $noderef = node_of $portid
114		130
115	our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie	131	Extracts and returns the noderef from a portid or a noderef.
116	our $PUBLIC = 0;
117	our $NODE;
118	our $PORT;
119		132
120	our %NODE; # node id to transport mapping, or "undef", for local node	133	=item $cv = resolve_node $noderef
121	our %PORT; # local ports
122	our %LISTENER; # local transports
123		134
124	sub NODE() { $NODE }	135	Takes an unresolved node reference that may contain hostnames and
		136	abbreviated IDs, resolves all of them and returns a resolved node
		137	reference.
125		138
126	{	139	In addition to C<address:port> pairs allowed in resolved noderefs, the
127	use POSIX ();	140	following forms are supported:
128	my $nodename = (POSIX::uname)[1];
129	$NODE = "$$\@$nodename";
130	}
131		141
132	sub _ANY_() { 1 }	142	=over 4
133	sub _any_() { \&_ANY_ }
134		143
135	sub add_node {	144	=item the empty string
136	my ($noderef) = @_;
137		145
138	return $NODE{$noderef}	146	An empty-string component gets resolved as if the default port (4040) was
139	if exists $NODE{$noderef};	147	specified.
140		148
141	for (split /,/, $noderef) {	149	=item naked port numbers (e.g. C<1234>)
142	return $NODE{$noderef} = $NODE{$_}
143	if exists $NODE{$_};
144	}
145		150
146	# for indirect sends, use a different class	151	These are resolved by prepending the local nodename and a colon, to be
147	my $node = new AnyEvent::MP::Node::Direct $noderef;	152	further resolved.
148		153
149	$NODE{$_} = $node	154	=item hostnames (e.g. C<localhost:1234>, C<localhost>)
150	for $noderef, split /,/, $noderef;
151		155
152	$node	156	These are resolved by using AnyEvent::DNS to resolve them, optionally
153	}	157	looking up SRV records for the C<aemp=4040> port, if no port was
		158	specified.
		159
		160	=back
		161
		162	=item $SELF
		163
		164	Contains the current port id while executing C<rcv> callbacks or C<psub>
		165	blocks.
		166
		167	=item SELF, %SELF, @SELF...
		168
		169	Due to some quirks in how perl exports variables, it is impossible to
		170	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		171	module, but only C<$SELF> is currently used.
154		172
155	=item snd $portid, type => @data	173	=item snd $portid, type => @data
156		174
157	=item snd $portid, @msg	175	=item snd $portid, @msg
158		176
159	Send the given message to the given port ID, which can identify either a	177	Send the given message to the given port ID, which can identify either
160	local or a remote port.	178	a local or a remote port, and can be either a string or soemthignt hat
		179	stringifies a sa port ID (such as a port object :).
161		180
162	While the message can be about anything, it is highly recommended to use	181	While the message can be about anything, it is highly recommended to use a
163	a constant string as first element.	182	string as first element (a portid, or some word that indicates a request
		183	type etc.).
164		184
165	The message data effectively becomes read-only after a call to this	185	The message data effectively becomes read-only after a call to this
166	function: modifying any argument is not allowed and can cause many	186	function: modifying any argument is not allowed and can cause many
167	problems.	187	problems.
168		188
…		…
170	JSON is used, then only strings, numbers and arrays and hashes consisting	190	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	191	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	192	that Storable can serialise and deserialise is allowed, and for the local
173	node, anything can be passed.	193	node, anything can be passed.
174		194
175	=cut	195	=item kil $portid[, @reason]
176		196
177	sub snd(@) {	197	Kill the specified port with the given C<@reason>.
		198
		199	If no C<@reason> is specified, then the port is killed "normally" (linked
		200	ports will not be kileld, or even notified).
		201
		202	Otherwise, linked ports get killed with the same reason (second form of
		203	C<mon>, see below).
		204
		205	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		206	will be reported as reason C<< die => $@ >>.
		207
		208	Transport/communication errors are reported as C<< transport_error =>
		209	$message >>.
		210
		211	=item $guard = mon $portid, $cb->(@reason)
		212
		213	=item $guard = mon $portid, $otherport
		214
		215	=item $guard = mon $portid, $otherport, @msg
		216
		217	Monitor the given port and do something when the port is killed.
		218
		219	In the first form, the callback is simply called with any number
		220	of C<@reason> elements (no @reason means that the port was deleted
		221	"normally"). Note also that I<< the callback B<must> never die >>, so use
		222	C<eval> if unsure.
		223
		224	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
		225	a @reason was specified, i.e. on "normal" kils nothing happens, while
		226	under all other conditions, the other port is killed with the same reason.
		227
		228	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
		229
		230	Example: call a given callback when C<$port> is killed.
		231
		232	mon $port, sub { warn "port died because of <@_>\n" };
		233
		234	Example: kill ourselves when C<$port> is killed abnormally.
		235
		236	mon $port, $self;
		237
		238	Example: send us a restart message another C<$port> is killed.
		239
		240	mon $port, $self => "restart";
		241
		242	=cut
		243
		244	sub mon {
178	my ($noderef, $port) = split /#/, shift, 2;	245	my ($noderef, $port) = split /#/, shift, 2;
179		246
180	add_node $noderef	247	my $node = $NODE{$noderef} \|\| add_node $noderef;
181	unless exists $NODE{$noderef};
182		248
183	$NODE{$noderef}->send (["$port", [@_]]);	249	my $cb = shift;
		250
		251	unless (ref $cb) {
		252	if (@_) {
		253	# send a kill info message
		254	my (@msg) = ($cb, @_);
		255	$cb = sub { snd @msg, @_ };
		256	} else {
		257	# simply kill other port
		258	my $port = $cb;
		259	$cb = sub { kil $port, @_ if @_ };
		260	}
		261	}
		262
		263	$node->monitor ($port, $cb);
		264
		265	defined wantarray
		266	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
184	}	267	}
185		268
		269	=item $guard = mon_guard $port, $ref, $ref...
		270
		271	Monitors the given C<$port> and keeps the passed references. When the port
		272	is killed, the references will be freed.
		273
		274	Optionally returns a guard that will stop the monitoring.
		275
		276	This function is useful when you create e.g. timers or other watchers and
		277	want to free them when the port gets killed:
		278
		279	$port->rcv (start => sub {
		280	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		281	undef $timer if 0.9 < rand;
		282	});
		283	});
		284
		285	=cut
		286
		287	sub mon_guard {
		288	my ($port, @refs) = @_;
		289
		290	mon $port, sub { 0 && @refs }
		291	}
		292
		293	=item lnk $port1, $port2
		294
		295	Link two ports. This is simply a shorthand for:
		296
		297	mon $port1, $port2;
		298	mon $port2, $port1;
		299
		300	It means that if either one is killed abnormally, the other one gets
		301	killed as well.
		302
		303	=item $local_port = port
		304
		305	Create a new local port object that supports message matching.
		306
		307	=item $portid = port { my @msg = @_; $finished }
		308
		309	Creates a "mini port", that is, a very lightweight port without any
		310	pattern matching behind it, and returns its ID.
		311
		312	The block will be called for every message received on the port. When the
		313	callback returns a true value its job is considered "done" and the port
		314	will be destroyed. Otherwise it will stay alive.
		315
		316	The message will be passed as-is, no extra argument (i.e. no port id) will
		317	be passed to the callback.
		318
		319	If you need the local port id in the callback, this works nicely:
		320
		321	my $port; $port = miniport {
		322	snd $otherport, reply => $port;
		323	};
		324
		325	=cut
		326
		327	sub port(;&) {
		328	my $id = "$UNIQ." . $ID++;
		329	my $port = "$NODE#$id";
		330
		331	if (@_) {
		332	my $cb = shift;
		333	$PORT{$id} = sub {
		334	local $SELF = $port;
		335	eval {
		336	&$cb
		337	and kil $id;
		338	};
		339	_self_die if $@;
		340	};
		341	} else {
		342	my $self = bless {
		343	id => "$NODE#$id",
		344	}, "AnyEvent::MP::Port";
		345
		346	$PORT_DATA{$id} = $self;
		347	$PORT{$id} = sub {
		348	local $SELF = $port;
		349
		350	eval {
		351	for (@{ $self->{rc0}{$_[0]} }) {
		352	$_ && &{$_->[0]}
		353	&& undef $_;
		354	}
		355
		356	for (@{ $self->{rcv}{$_[0]} }) {
		357	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		358	&& &{$_->[0]}
		359	&& undef $_;
		360	}
		361
		362	for (@{ $self->{any} }) {
		363	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		364	&& &{$_->[0]}
		365	&& undef $_;
		366	}
		367	};
		368	_self_die if $@;
		369	};
		370	}
		371
		372	$port
		373	}
		374
		375	=item reg $portid, $name
		376
		377	Registers the given port under the name C<$name>. If the name already
		378	exists it is replaced.
		379
		380	A port can only be registered under one well known name.
		381
		382	A port automatically becomes unregistered when it is killed.
		383
		384	=cut
		385
		386	sub reg(@) {
		387	my ($portid, $name) = @_;
		388
		389	$REG{$name} = $portid;
		390	}
		391
186	=item rcv $portid, type => $callback->(@msg)	392	=item rcv $portid, tagstring => $callback->(@msg), ...
187		393
188	=item rcv $portid, $smartmatch => $callback->(@msg)	394	=item rcv $portid, $smartmatch => $callback->(@msg), ...
189		395
190	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	396	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
191		397
192	Register a callback on the port identified by C<$portid>, which I<must> be	398	Register callbacks to be called on matching messages on the given port.
193	a local port.
194		399
195	The callback has to return a true value when its work is done, after	400	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	401	which is will be removed, or a false value in which case it will stay
197	registered.	402	registered.
198		403
		404	The global C<$SELF> (exported by this module) contains C<$portid> while
		405	executing the callback.
		406
		407	Runtime errors wdurign callback execution will result in the port being
		408	C<kil>ed.
		409
199	If the match is an array reference, then it will be matched against the	410	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	411	first elements of the message, otherwise only the first element is being
201	matched.	412	matched.
202		413
203	Any element in the match that is specified as C<_any_> (a function	414	Any element in the match that is specified as C<_any_> (a function
…		…
208	also the most efficient match (by far).	419	also the most efficient match (by far).
209		420
210	=cut	421	=cut
211		422
212	sub rcv($@) {	423	sub rcv($@) {
213	my ($port, $match, $cb) = @_;
214
215	my $port = $PORT{$port}
216	or do {
217	my ($noderef, $lport) = split /#/, $port;	424	my ($noderef, $port) = split /#/, shift, 2;
218	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	425
		426	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
219	or Carp::croak "$port: can only rcv on local ports";	427	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
220		428
221	$PORT{$lport}	429	my $self = $PORT_DATA{$port}
222	or Carp::croak "$port: port does not exist";	430	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
223
224	$PORT{$port} = $PORT{$lport} # also return
225	};
226		431
		432	"AnyEvent::MP::Port" eq ref $self
		433	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
		434
		435	while (@_) {
		436	my ($match, $cb) = splice @_, 0, 2;
		437
227	if (!ref $match) {	438	if (!ref $match) {
228	push @{ $port->{rc0}{$match} }, [$cb];	439	push @{ $self->{rc0}{$match} }, [$cb];
229	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	440	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
230	my ($type, @match) = @$match;	441	my ($type, @match) = @$match;
231	@match	442	@match
232	? push @{ $port->{rcv}{$match->[0]} }, [$cb, \@match]	443	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
233	: push @{ $port->{rc0}{$match->[0]} }, [$cb];	444	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
234	} else {	445	} else {
235	push @{ $port->{any} }, [$cb, $match];	446	push @{ $self->{any} }, [$cb, $match];
		447	}
236	}	448	}
237	}	449	}
238		450
239	sub _inject {	451	=item $closure = psub { BLOCK }
240	my ($port, $msg) = @{+shift};
241		452
242	$port = $PORT{$port}	453	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
243	or return;	454	closure is executed, sets up the environment in the same way as in C<rcv>
		455	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
244		456
245	@_ = @$msg;	457	This is useful when you register callbacks from C<rcv> callbacks:
246		458
247	for (@{ $port->{rc0}{$msg->[0]} }) {	459	rcv delayed_reply => sub {
248	$_ && &{$_->[0]}	460	my ($delay, @reply) = @_;
249	&& undef $_;	461	my $timer = AE::timer $delay, 0, psub {
		462	snd @reply, $SELF;
		463	};
250	}	464	};
251		465
252	for (@{ $port->{rcv}{$msg->[0]} }) {	466	=cut
253	$_ && [@_[1..$#{$_->[1]}]] ~~ $_->[1]
254	&& &{$_->[0]}
255	&& undef $_;
256	}
257		467
258	for (@{ $port->{any} }) {	468	sub psub(&) {
259	$_ && [@_[0..$#{$_->[1]}]] ~~ $_->[1]	469	my $cb = shift;
260	&& &{$_->[0]}	470
261	&& undef $_;	471	my $port = $SELF
		472	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		473
		474	sub {
		475	local $SELF = $port;
		476
		477	if (wantarray) {
		478	my @res = eval { &$cb };
		479	_self_die if $@;
		480	@res
		481	} else {
		482	my $res = eval { &$cb };
		483	_self_die if $@;
		484	$res
		485	}
262	}	486	}
263	}	487	}
264		488
265	sub normalise_noderef($) {
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	];
298	}
299	$cv->end;
300	};
301
302	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;
303	#
304	# for (@ipv4) {
305	# push @res, [
306	# $pri,
307	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,
308	# ];
309	# }
310	} else {
311	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"
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	}
325	}
326	}
327
328	$cv->end;
329
330	$cv
331	}
332
333	sub become_public {
334	return if $PUBLIC;
335
336	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;
337	my @args = @_;
338
339	$NODE = (normalise_noderef $noderef)->recv;
340
341	for my $t (split /,/, $NODE) {
342	$NODE{$t} = $NODE{""};
343
344	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;
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	;
362	}
363
364	$PUBLIC = 1;
365	}
366
367	=back	489	=back
368		490
		491	=head1 FUNCTIONS FOR NODES
		492
		493	=over 4
		494
		495	=item become_public $noderef
		496
		497	Tells the node to become a public node, i.e. reachable from other nodes.
		498
		499	The first argument is the (unresolved) node reference of the local node
		500	(if missing then the empty string is used).
		501
		502	It is quite common to not specify anything, in which case the local node
		503	tries to listen on the default port, or to only specify a port number, in
		504	which case AnyEvent::MP tries to guess the local addresses.
		505
		506	=cut
		507
		508	=back
		509
369	=head1 NODE MESSAGES	510	=head1 NODE MESSAGES
370		511
371	Nodes understand the following messages sent to them:	512	Nodes understand the following messages sent to them. Many of them take
		513	arguments called C<@reply>, which will simply be used to compose a reply
		514	message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
		515	the remaining arguments are simply the message data.
		516
		517	While other messages exist, they are not public and subject to change.
372		518
373	=over 4	519	=over 4
374		520
375	=cut	521	=cut
376		522
377	#############################################################################	523	=item lookup => $name, @reply
378	# self node code
379		524
380	sub _new_port($) {	525	Replies with the port ID of the specified well-known port, or C<undef>.
381	my ($name) = @_;
382		526
383	my ($noderef, $portname) = split /#/, $name;	527	=item devnull => ...
384		528
385	$PORT{$name} =	529	Generic data sink/CPU heat conversion.
386	$PORT{$portname} = {
387	names => [$name, $portname],
388	};
389	}
390
391	$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE;
392	_new_port "";
393		530
394	=item relay => $port, @msg	531	=item relay => $port, @msg
395		532
396	Simply forwards the message to the given port.	533	Simply forwards the message to the given port.
397		534
398	=cut
399
400	rcv "", relay => \&snd;
401
402	=item eval => $string[ @reply]	535	=item eval => $string[ @reply]
403		536
404	Evaluates the given string. If C<@reply> is given, then a message of the	537	Evaluates the given string. If C<@reply> is given, then a message of the
405	form C<@reply, $@, @evalres> is sent (C<$reply[0]> is the port to reply to).	538	form C<@reply, $@, @evalres> is sent.
406		539
407	=cut	540	Example: crash another node.
408		541
409	rcv "", eval => sub {	542	snd $othernode, eval => "exit";
410	my (undef, $string, @reply) = @_;
411	my @res = eval $string;
412	snd @reply, "$@", @res if @reply;
413	};
414		543
415	=item time => @reply	544	=item time => @reply
416		545
417	Replies the the current node time to C<@reply>.	546	Replies the the current node time to C<@reply>.
418		547
419	=cut	548	Example: tell the current node to send the current time to C<$myport> in a
		549	C<timereply> message.
420		550
421	rcv "", time => sub { shift; snd @_, AE::time };	551	snd $NODE, time => $myport, timereply => 1, 2;
		552	# => snd $myport, timereply => 1, 2, <time>
		553
		554	=back
		555
		556	=head1 AnyEvent::MP vs. Distributed Erlang
		557
		558	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node
		559	== aemp node, erlang process == aemp port), so many of the documents and
		560	programming techniques employed by erlang apply to AnyEvent::MP. Here is a
		561	sample:
		562
		563	http://www.erlang.se/doc/programming_rules.shtml
		564	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		565	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
		566	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		567
		568	Despite the similarities, there are also some important differences:
		569
		570	=over 4
		571
		572	=item * Node references contain the recipe on how to contact them.
		573
		574	Erlang relies on special naming and DNS to work everywhere in the
		575	same way. AEMP relies on each node knowing it's own address(es), with
		576	convenience functionality.
		577
		578	This means that AEMP requires a less tightly controlled environment at the
		579	cost of longer node references and a slightly higher management overhead.
		580
		581	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		582
		583	Erlang uses processes that selctively receive messages, and therefore
		584	needs a queue. AEMP is event based, queuing messages would serve no useful
		585	purpose.
		586
		587	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		588
		589	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		590
		591	Sending messages in erlang is synchronous and blocks the process. AEMP
		592	sends are immediate, connection establishment is handled in the
		593	background.
		594
		595	=item * Erlang can silently lose messages, AEMP cannot.
		596
		597	Erlang makes few guarantees on messages delivery - messages can get lost
		598	without any of the processes realising it (i.e. you send messages a, b,
		599	and c, and the other side only receives messages a and c).
		600
		601	AEMP guarantees correct ordering, and the guarantee that there are no
		602	holes in the message sequence.
		603
		604	=item * In erlang, processes can be declared dead and later be found to be
		605	alive.
		606
		607	In erlang it can happen that a monitored process is declared dead and
		608	linked processes get killed, but later it turns out that the process is
		609	still alive - and can receive messages.
		610
		611	In AEMP, when port monitoring detects a port as dead, then that port will
		612	eventually be killed - it cannot happen that a node detects a port as dead
		613	and then later sends messages to it, finding it is still alive.
		614
		615	=item * Erlang can send messages to the wrong port, AEMP does not.
		616
		617	In erlang it is quite possible that a node that restarts reuses a process
		618	ID known to other nodes for a completely different process, causing
		619	messages destined for that process to end up in an unrelated process.
		620
		621	AEMP never reuses port IDs, so old messages or old port IDs floating
		622	around in the network will not be sent to an unrelated port.
		623
		624	=item * Erlang uses unprotected connections, AEMP uses secure
		625	authentication and can use TLS.
		626
		627	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		628	securely authenticate nodes.
		629
		630	=item * The AEMP protocol is optimised for both text-based and binary
		631	communications.
		632
		633	The AEMP protocol, unlike the erlang protocol, supports both
		634	language-independent text-only protocols (good for debugging) and binary,
		635	language-specific serialisers (e.g. Storable).
		636
		637	It has also been carefully designed to be implementable in other languages
		638	with a minimum of work while gracefully degrading fucntionality to make the
		639	protocol simple.
422		640
423	=back	641	=back
424		642
425	=head1 SEE ALSO	643	=head1 SEE ALSO
426		644

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.4 by root, Sat Aug 1 07:36:30 2009 UTC vs. Revision 1.30 by root, Tue Aug 4 23:35:51 2009 UTC

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Revision 1.4 by root, Sat Aug 1 07:36:30 2009 UTC vs.
Revision 1.30 by root, Tue Aug 4 23:35:51 2009 UTC