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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.7 by root, Sat Aug 1 15:04:30 2009 UTC vs.
Revision 1.26 by root, Tue Aug 4 22:05:43 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
32	At the moment, this module family is severly brokena nd underdocumented,	38	At the moment, this module family is severly broken and underdocumented,
33	so do not use. This was uploaded mainly to resreve the CPAN namespace -	39	so do not use. This was uploaded mainly to reserve the CPAN namespace -
34	stay tuned!	40	stay tuned! The basic API should be finished, however.
35		41
36	=head1 CONCEPTS	42	=head1 CONCEPTS
37		43
38	=over 4	44	=over 4
39		45
…		…
72		78
73	=cut	79	=cut
74		80
75	package AnyEvent::MP;	81	package AnyEvent::MP;
76		82
77	use AnyEvent::MP::Util ();
78	use AnyEvent::MP::Node;	83	use AnyEvent::MP::Base;
79	use AnyEvent::MP::Transport;
80		84
81	use utf8;
82	use common::sense;	85	use common::sense;
83		86
84	use Carp ();	87	use Carp ();
85		88
86	use AE ();	89	use AE ();
87		90
88	use base "Exporter";	91	use base "Exporter";
89		92
90	our $VERSION = '0.01';	93	our $VERSION = '0.1';
91	our @EXPORT = qw(NODE $NODE $PORT snd rcv _any_);	94	our @EXPORT = qw(
		95	NODE $NODE *SELF node_of _any_
		96	become_slave become_public
		97	snd rcv mon kil reg psub
		98	port
		99	);
92		100
93	our $DEFAULT_SECRET;	101	our $SELF;
94	our $DEFAULT_PORT = "4040";
95		102
96	our $CONNECT_INTERVAL = 5; # new connect every 5s, at least	103	sub _self_die() {
97	our $CONNECT_TIMEOUT = 30; # includes handshake	104	my $msg = $@;
98		105	$msg =~ s/\n+$// unless ref $msg;
99	sub default_secret {	106	kil $SELF, die => $msg;
100	unless (defined $DEFAULT_SECRET) {
101	if (open my $fh, "<$ENV{HOME}/.aemp-secret") {
102	sysread $fh, $DEFAULT_SECRET, -s $fh;
103	} else {
104	$DEFAULT_SECRET = AnyEvent::MP::Util::nonce 32;
105	}
106	}
107
108	$DEFAULT_SECRET
109	}	107	}
110		108
111	=item NODE / $NODE	109	=item $thisnode = NODE / $NODE
112		110
113	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	111	The C<NODE> function returns, and the C<$NODE> variable contains
114	the local node. The value is initialised by a call to C<become_public> or	112	the noderef of the local node. The value is initialised by a call
115	C<become_slave>, after which all local port identifiers become invalid.	113	to C<become_public> or C<become_slave>, after which all local port
		114	identifiers become invalid.
116		115
117	=cut	116	=item $noderef = node_of $portid
118		117
119	our $UNIQ = sprintf "%x.%x", $$, time; # per-process/node unique cookie	118	Extracts and returns the noderef from a portid or a noderef.
120	our $ID = "a0";
121	our $PUBLIC = 0;
122	our $NODE;
123	our $PORT;
124		119
125	our %NODE; # node id to transport mapping, or "undef", for local node	120	=item $SELF
126	our %PORT; # local ports
127	our %LISTENER; # local transports
128		121
129	sub NODE() { $NODE }	122	Contains the current port id while executing C<rcv> callbacks or C<psub>
		123	blocks.
130		124
131	{	125	=item SELF, %SELF, @SELF...
132	use POSIX ();
133	my $nodename = (POSIX::uname)[1];
134	$NODE = "$$\@$nodename";
135	}
136		126
137	sub _ANY_() { 1 }	127	Due to some quirks in how perl exports variables, it is impossible to
138	sub _any_() { \&_ANY_ }	128	just export C<$SELF>, all the symbols called C<SELF> are exported by this
139		129	module, but only C<$SELF> is currently used.
140	sub add_node {
141	my ($noderef) = @_;
142
143	return $NODE{$noderef}
144	if exists $NODE{$noderef};
145
146	for (split /,/, $noderef) {
147	return $NODE{$noderef} = $NODE{$_}
148	if exists $NODE{$_};
149	}
150
151	# for indirect sends, use a different class
152	my $node = new AnyEvent::MP::Node::Direct $noderef;
153
154	$NODE{$_} = $node
155	for $noderef, split /,/, $noderef;
156
157	$node
158	}
159		130
160	=item snd $portid, type => @data	131	=item snd $portid, type => @data
161		132
162	=item snd $portid, @msg	133	=item snd $portid, @msg
163		134
164	Send the given message to the given port ID, which can identify either a	135	Send the given message to the given port ID, which can identify either
165	local or a remote port.	136	a local or a remote port, and can be either a string or soemthignt hat
		137	stringifies a sa port ID (such as a port object :).
166		138
167	While the message can be about anything, it is highly recommended to use	139	While the message can be about anything, it is highly recommended to use a
168	a constant string as first element.	140	string as first element (a portid, or some word that indicates a request
		141	type etc.).
169		142
170	The message data effectively becomes read-only after a call to this	143	The message data effectively becomes read-only after a call to this
171	function: modifying any argument is not allowed and can cause many	144	function: modifying any argument is not allowed and can cause many
172	problems.	145	problems.
173		146
…		…
175	JSON is used, then only strings, numbers and arrays and hashes consisting	148	JSON is used, then only strings, numbers and arrays and hashes consisting
176	of those are allowed (no objects). When Storable is used, then anything	149	of those are allowed (no objects). When Storable is used, then anything
177	that Storable can serialise and deserialise is allowed, and for the local	150	that Storable can serialise and deserialise is allowed, and for the local
178	node, anything can be passed.	151	node, anything can be passed.
179		152
180	=cut	153	=item kil $portid[, @reason]
181		154
182	sub snd(@) {	155	Kill the specified port with the given C<@reason>.
		156
		157	If no C<@reason> is specified, then the port is killed "normally" (linked
		158	ports will not be kileld, or even notified).
		159
		160	Otherwise, linked ports get killed with the same reason (second form of
		161	C<mon>, see below).
		162
		163	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		164	will be reported as reason C<< die => $@ >>.
		165
		166	Transport/communication errors are reported as C<< transport_error =>
		167	$message >>.
		168
		169	=item $guard = mon $portid, $cb->(@reason)
		170
		171	=item $guard = mon $portid, $otherport
		172
		173	=item $guard = mon $portid, $otherport, @msg
		174
		175	Monitor the given port and do something when the port is killed.
		176
		177	In the first form, the callback is simply called with any number
		178	of C<@reason> elements (no @reason means that the port was deleted
		179	"normally"). Note also that I<< the callback B<must> never die >>, so use
		180	C<eval> if unsure.
		181
		182	In the second form, the other port will be C<kil>'ed with C<@reason>, iff
		183	a @reason was specified, i.e. on "normal" kils nothing happens, while
		184	under all other conditions, the other port is killed with the same reason.
		185
		186	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
		187
		188	Example: call a given callback when C<$port> is killed.
		189
		190	mon $port, sub { warn "port died because of <@_>\n" };
		191
		192	Example: kill ourselves when C<$port> is killed abnormally.
		193
		194	mon $port, $self;
		195
		196	Example: send us a restart message another C<$port> is killed.
		197
		198	mon $port, $self => "restart";
		199
		200	=cut
		201
		202	sub mon {
183	my ($noderef, $port) = split /#/, shift, 2;	203	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
184		204
185	add_node $noderef	205	my $node = $NODE{$noderef} \|\| add_node $noderef;
186	unless exists $NODE{$noderef};
187		206
188	$NODE{$noderef}->send (["$port", [@_]]);	207	#TODO: ports must not be references
189	}	208	if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
		209	if (@_) {
		210	# send a kill info message
		211	my (@msg) = ($cb, @_);
		212	$cb = sub { snd @msg, @_ };
		213	} else {
		214	# simply kill other port
		215	my $port = $cb;
		216	$cb = sub { kil $port, @_ if @_ };
		217	}
		218	}
190		219
		220	$node->monitor ($port, $cb);
		221
		222	defined wantarray
		223	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
		224	}
		225
		226	=item $guard = mon_guard $port, $ref, $ref...
		227
		228	Monitors the given C<$port> and keeps the passed references. When the port
		229	is killed, the references will be freed.
		230
		231	Optionally returns a guard that will stop the monitoring.
		232
		233	This function is useful when you create e.g. timers or other watchers and
		234	want to free them when the port gets killed:
		235
		236	$port->rcv (start => sub {
		237	my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
		238	undef $timer if 0.9 < rand;
		239	});
		240	});
		241
		242	=cut
		243
		244	sub mon_guard {
		245	my ($port, @refs) = @_;
		246
		247	mon $port, sub { 0 && @refs }
		248	}
		249
		250	=item lnk $port1, $port2
		251
		252	Link two ports. This is simply a shorthand for:
		253
		254	mon $port1, $port2;
		255	mon $port2, $port1;
		256
		257	It means that if either one is killed abnormally, the other one gets
		258	killed as well.
		259
		260	=item $local_port = port
		261
		262	Create a new local port object that supports message matching.
		263
		264	=item $portid = port { my @msg = @_; $finished }
		265
		266	Creates a "mini port", that is, a very lightweight port without any
		267	pattern matching behind it, and returns its ID.
		268
		269	The block will be called for every message received on the port. When the
		270	callback returns a true value its job is considered "done" and the port
		271	will be destroyed. Otherwise it will stay alive.
		272
		273	The message will be passed as-is, no extra argument (i.e. no port id) will
		274	be passed to the callback.
		275
		276	If you need the local port id in the callback, this works nicely:
		277
		278	my $port; $port = miniport {
		279	snd $otherport, reply => $port;
		280	};
		281
		282	=cut
		283
		284	sub port(;&) {
		285	my $id = "$UNIQ." . $ID++;
		286	my $port = "$NODE#$id";
		287
		288	if (@_) {
		289	my $cb = shift;
		290	$PORT{$id} = sub {
		291	local $SELF = $port;
		292	eval {
		293	&$cb
		294	and kil $id;
		295	};
		296	_self_die if $@;
		297	};
		298	} else {
		299	my $self = bless {
		300	id => "$NODE#$id",
		301	}, "AnyEvent::MP::Port";
		302
		303	$PORT_DATA{$id} = $self;
		304	$PORT{$id} = sub {
		305	local $SELF = $port;
		306
		307	eval {
		308	for (@{ $self->{rc0}{$_[0]} }) {
		309	$_ && &{$_->[0]}
		310	&& undef $_;
		311	}
		312
		313	for (@{ $self->{rcv}{$_[0]} }) {
		314	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		315	&& &{$_->[0]}
		316	&& undef $_;
		317	}
		318
		319	for (@{ $self->{any} }) {
		320	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		321	&& &{$_->[0]}
		322	&& undef $_;
		323	}
		324	};
		325	_self_die if $@;
		326	};
		327	}
		328
		329	$port
		330	}
		331
		332	=item reg $portid, $name
		333
		334	Registers the given port under the name C<$name>. If the name already
		335	exists it is replaced.
		336
		337	A port can only be registered under one well known name.
		338
		339	A port automatically becomes unregistered when it is killed.
		340
		341	=cut
		342
		343	sub reg(@) {
		344	my ($portid, $name) = @_;
		345
		346	$REG{$name} = $portid;
		347	}
		348
191	=item rcv $portid, type => $callback->(@msg)	349	=item rcv $portid, tagstring => $callback->(@msg), ...
192		350
193	=item rcv $portid, $smartmatch => $callback->(@msg)	351	=item rcv $portid, $smartmatch => $callback->(@msg), ...
194		352
195	=item rcv $portid, [$smartmatch...] => $callback->(@msg)	353	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
196		354
197	Register a callback on the port identified by C<$portid>, which I<must> be	355	Register callbacks to be called on matching messages on the given port.
198	a local port.
199		356
200	The callback has to return a true value when its work is done, after	357	The callback has to return a true value when its work is done, after
201	which is will be removed, or a false value in which case it will stay	358	which is will be removed, or a false value in which case it will stay
202	registered.	359	registered.
203		360
		361	The global C<$SELF> (exported by this module) contains C<$portid> while
		362	executing the callback.
		363
		364	Runtime errors wdurign callback execution will result in the port being
		365	C<kil>ed.
		366
204	If the match is an array reference, then it will be matched against the	367	If the match is an array reference, then it will be matched against the
205	first elements of the message, otherwise only the first element is being	368	first elements of the message, otherwise only the first element is being
206	matched.	369	matched.
207		370
208	Any element in the match that is specified as C<_any_> (a function	371	Any element in the match that is specified as C<_any_> (a function
…		…
213	also the most efficient match (by far).	376	also the most efficient match (by far).
214		377
215	=cut	378	=cut
216		379
217	sub rcv($@) {	380	sub rcv($@) {
218	my ($port, $match, $cb) = @_;
219
220	my $port = $PORT{$port}
221	or do {
222	my ($noderef, $lport) = split /#/, $port;	381	my ($noderef, $port) = split /#/, shift, 2;
223	"AnyEvent::MP::Node::Self" eq ref $NODE{$noderef}	382
		383	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
224	or Carp::croak "$port: can only rcv on local ports";	384	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
225		385
226	$PORT{$lport}	386	my $self = $PORT_DATA{$port}
227	or Carp::croak "$port: port does not exist";	387	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
228
229	$PORT{$port} = $PORT{$lport} # also return
230	};
231		388
		389	"AnyEvent::MP::Port" eq ref $self
		390	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
		391
		392	while (@_) {
		393	my ($match, $cb) = splice @_, 0, 2;
		394
232	if (!ref $match) {	395	if (!ref $match) {
233	push @{ $port->{rc0}{$match} }, [$cb];	396	push @{ $self->{rc0}{$match} }, [$cb];
234	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	397	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
235	my ($type, @match) = @$match;	398	my ($type, @match) = @$match;
236	@match	399	@match
237	? push @{ $port->{rcv}{$match->[0]} }, [$cb, \@match]	400	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
238	: push @{ $port->{rc0}{$match->[0]} }, [$cb];	401	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
239	} else {
240	push @{ $port->{any} }, [$cb, $match];
241	}
242	}
243
244	sub _inject {
245	my ($port, $msg) = @{+shift};
246
247	$port = $PORT{$port}
248	or return;
249
250	@_ = @$msg;
251
252	for (@{ $port->{rc0}{$msg->[0]} }) {
253	$_ && &{$_->[0]}
254	&& undef $_;
255	}
256
257	for (@{ $port->{rcv}{$msg->[0]} }) {
258	$_ && [@_[1..$#{$_->[1]}]] ~~ $_->[1]
259	&& &{$_->[0]}
260	&& undef $_;
261	}
262
263	for (@{ $port->{any} }) {
264	$_ && [@_[0..$#{$_->[1]}]] ~~ $_->[1]
265	&& &{$_->[0]}
266	&& undef $_;
267	}
268	}
269
270	sub normalise_noderef($) {
271	my ($noderef) = @_;
272
273	my $cv = AE::cv;
274	my @res;
275
276	$cv->begin (sub {
277	my %seen;
278	my @refs;
279	for (sort { $a->[0] <=> $b->[0] } @res) {
280	push @refs, $_->[1] unless $seen{$_->[1]}++
281	}
282	shift->send (join ",", @refs);
283	});
284
285	$noderef = $DEFAULT_PORT unless length $noderef;
286
287	my $idx;
288	for my $t (split /,/, $noderef) {
289	my $pri = ++$idx;
290
291	#TODO: this should be outside normalise_noderef and in become_public
292	if ($t =~ /^\d*$/) {
293	my $nodename = (POSIX::uname)[1];
294
295	$cv->begin;
296	AnyEvent::Socket::resolve_sockaddr $nodename, $t \|\| "aemp=$DEFAULT_PORT", "tcp", 0, undef, sub {
297	for (@_) {
298	my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3];
299	push @res, [
300	$pri += 1e-5,
301	AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service
302	];
303	}
304	$cv->end;
305	};
306
307	# my (undef, undef, undef, undef, @ipv4) = gethostbyname $nodename;
308	#
309	# for (@ipv4) {
310	# push @res, [
311	# $pri,
312	# AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $_, $t \|\| $DEFAULT_PORT,
313	# ];
314	# }
315	} else {	402	} else {
316	my ($host, $port) = AnyEvent::Socket::parse_hostport $t, "aemp=$DEFAULT_PORT"	403	push @{ $self->{any} }, [$cb, $match];
317	or Carp::croak "$t: unparsable transport descriptor";
318
319	$cv->begin;
320	AnyEvent::Socket::resolve_sockaddr $host, $port, "tcp", 0, undef, sub {
321	for (@_) {
322	my ($service, $host) = AnyEvent::Socket::unpack_sockaddr $_->[3];
323	push @res, [
324	$pri += 1e-5,
325	AnyEvent::Socket::format_hostport AnyEvent::Socket::format_address $host, $service
326	];
327	}
328	$cv->end;
329	}
330	}	404	}
331	}	405	}
332
333	$cv->end;
334
335	$cv
336	}	406	}
337		407
338	sub become_public {	408	=item $closure = psub { BLOCK }
339	return if $PUBLIC;
340		409
341	my $noderef = join ",", ref $_[0] ? @{+shift} : shift;	410	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
342	my @args = @_;	411	closure is executed, sets up the environment in the same way as in C<rcv>
		412	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
343		413
344	$NODE = (normalise_noderef $noderef)->recv;	414	This is useful when you register callbacks from C<rcv> callbacks:
345		415
346	for my $t (split /,/, $NODE) {	416	rcv delayed_reply => sub {
347	$NODE{$t} = $NODE{""};	417	my ($delay, @reply) = @_;
348		418	my $timer = AE::timer $delay, 0, psub {
349	my ($host, $port) = AnyEvent::Socket::parse_hostport $t;	419	snd @reply, $SELF;
350
351	$LISTENER{$t} = AnyEvent::MP::Transport::mp_server $host, $port,
352	@args,
353	on_error => sub {
354	die "on_error<@_>\n";#d#
355	},
356	on_connect => sub {
357	my ($tp) = @_;
358
359	$NODE{$tp->{remote_id}} = $_[0];
360	},
361	sub {
362	my ($tp) = @_;
363
364	$NODE{"$tp->{peerhost}:$tp->{peerport}"} = $tp;
365	},
366	;	420	};
		421	};
		422
		423	=cut
		424
		425	sub psub(&) {
		426	my $cb = shift;
		427
		428	my $port = $SELF
		429	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		430
		431	sub {
		432	local $SELF = $port;
		433
		434	if (wantarray) {
		435	my @res = eval { &$cb };
		436	_self_die if $@;
		437	@res
		438	} else {
		439	my $res = eval { &$cb };
		440	_self_die if $@;
		441	$res
		442	}
367	}	443	}
368
369	$PUBLIC = 1;
370	}	444	}
		445
		446	=back
		447
		448	=head1 FUNCTIONS FOR NODES
		449
		450	=over 4
		451
		452	=item become_public endpoint...
		453
		454	Tells the node to become a public node, i.e. reachable from other nodes.
		455
		456	If no arguments are given, or the first argument is C<undef>, then
		457	AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
		458	local nodename resolves to.
		459
		460	Otherwise the first argument must be an array-reference with transport
		461	endpoints ("ip:port", "hostname:port") or port numbers (in which case the
		462	local nodename is used as hostname). The endpoints are all resolved and
		463	will become the node reference.
		464
		465	=cut
371		466
372	=back	467	=back
373		468
374	=head1 NODE MESSAGES	469	=head1 NODE MESSAGES
375		470
…		…
380		475
381	=over 4	476	=over 4
382		477
383	=cut	478	=cut
384		479
385	#############################################################################	480	=item lookup => $name, @reply
386	# self node code
387		481
388	sub _new_port($) {	482	Replies with the port ID of the specified well-known port, or C<undef>.
389	my ($name) = @_;
390
391	my ($noderef, $portname) = split /#/, $name;
392
393	$PORT{$name} =
394	$PORT{$portname} = {
395	names => [$name, $portname],
396	};
397	}
398
399	$NODE{""} = new AnyEvent::MP::Node::Self noderef => $NODE;
400	_new_port "";
401		483
402	=item devnull => ...	484	=item devnull => ...
403		485
404	Generic data sink/CPU heat conversion.	486	Generic data sink/CPU heat conversion.
405		487
406	=cut
407
408	rcv "", devnull => sub { () };
409
410	=item relay => $port, @msg	488	=item relay => $port, @msg
411		489
412	Simply forwards the message to the given port.	490	Simply forwards the message to the given port.
413
414	=cut
415
416	rcv "", relay => sub { \&snd; () };
417		491
418	=item eval => $string[ @reply]	492	=item eval => $string[ @reply]
419		493
420	Evaluates the given string. If C<@reply> is given, then a message of the	494	Evaluates the given string. If C<@reply> is given, then a message of the
421	form C<@reply, $@, @evalres> is sent.	495	form C<@reply, $@, @evalres> is sent.
422		496
423	Example: crash another node.	497	Example: crash another node.
424		498
425	snd $othernode, eval => "exit";	499	snd $othernode, eval => "exit";
426		500
427	=cut
428
429	rcv "", eval => sub {
430	my (undef, $string, @reply) = @_;
431	my @res = eval $string;
432	snd @reply, "$@", @res if @reply;
433	()
434	};
435
436	=item time => @reply	501	=item time => @reply
437		502
438	Replies the the current node time to C<@reply>.	503	Replies the the current node time to C<@reply>.
439		504
440	Example: tell the current node to send the current time to C<$myport> in a	505	Example: tell the current node to send the current time to C<$myport> in a
441	C<timereply> message.	506	C<timereply> message.
442		507
443	snd $NODE, time => $myport, timereply => 1, 2;	508	snd $NODE, time => $myport, timereply => 1, 2;
444	# => snd $myport, timereply => 1, 2, <time>	509	# => snd $myport, timereply => 1, 2, <time>
445		510
446	=cut	511	=back
447		512
448	rcv "", time => sub { shift; snd @_, AE::time; () };	513	=head1 AnyEvent::MP vs. Distributed Erlang
		514
		515	AnyEvent::MP got lots of its ideas from distributed erlang. Despite the
		516	similarities (erlang node == aemp node, erlang process == aemp port and so
		517	on), there are also some important differences:
		518
		519	=over 4
		520
		521	=item * Node references contain the recipe on how to contact them.
		522
		523	Erlang relies on special naming and DNS to work everywhere in the
		524	same way. AEMP relies on each node knowing it's own address(es), with
		525	convenience functionality.
		526
		527	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		528
		529	Erlang uses processes that selctively receive messages, and therefore
		530	needs a queue. AEMP is event based, queuing messages would serve no useful
		531	purpose.
		532
		533	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		534
		535	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		536
		537	Sending messages in erlang is synchronous and blocks the process. AEMP
		538	sends are immediate, connection establishment is handled in the
		539	background.
		540
		541	=item * Erlang can silently lose messages, AEMP cannot.
		542
		543	Erlang makes few guarantees on messages delivery - messages can get lost
		544	without any of the processes realising it (i.e. you send messages a, b,
		545	and c, and the other side only receives messages a and c).
		546
		547	AEMP guarantees correct ordering, and the guarantee that there are no
		548	holes in the message sequence.
		549
		550	=item * In erlang, processes can be declared dead and later be found to be
		551	alive.
		552
		553	In erlang it can happen that a monitored process is declared dead and
		554	linked processes get killed, but later it turns out that the process is
		555	still alive - and can receive messages.
		556
		557	In AEMP, when port monitoring detects a port as dead, then that port will
		558	eventually be killed - it cannot happen that a node detects a port as dead
		559	and then later sends messages to it, finding it is still alive.
		560
		561	=item * Erlang can send messages to the wrong port, AEMP does not.
		562
		563	In erlang it is quite possible that a node that restarts reuses a process
		564	ID known to other nodes for a completely different process, causing
		565	messages destined for that process to end up in an unrelated process.
		566
		567	AEMP never reuses port IDs, so old messages or old port IDs floating
		568	around in the network will not be sent to an unrelated port.
		569
		570	=item * Erlang uses unprotected connections, AEMP uses secure
		571	authentication and can use TLS.
		572
		573	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		574	securely authenticate nodes.
449		575
450	=back	576	=back
451		577
452	=head1 SEE ALSO	578	=head1 SEE ALSO
453		579

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.7 by root, Sat Aug 1 15:04:30 2009 UTC vs. Revision 1.26 by root, Tue Aug 4 22:05:43 2009 UTC

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Revision 1.26 by root, Tue Aug 4 22:05:43 2009 UTC