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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.8 by root, Sun Aug 2 14:44:37 2009 UTC vs.
Revision 1.27 by root, Tue Aug 4 22:13:45 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
…		…
82		88
83	use AE ();	89	use AE ();
84		90
85	use base "Exporter";	91	use base "Exporter";
86		92
87	our $VERSION = '0.01';	93	our $VERSION = '0.1';
88	our @EXPORT = qw(	94	our @EXPORT = qw(
89	NODE $NODE $PORT snd rcv _any_	95	NODE $NODE *SELF node_of _any_
90	create_port create_port_on
91	become_slave become_public	96	become_slave become_public
		97	snd rcv mon kil reg psub
		98	port
92	);	99	);
93		100
		101	our $SELF;
		102
		103	sub _self_die() {
		104	my $msg = $@;
		105	$msg =~ s/\n+$// unless ref $msg;
		106	kil $SELF, die => $msg;
		107	}
		108
94	=item NODE / $NODE	109	=item $thisnode = NODE / $NODE
95		110
96	The C<NODE ()> function and the C<$NODE> variable contain the noderef of	111	The C<NODE> function returns, and the C<$NODE> variable contains
97	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
98	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.
		115
		116	=item $noderef = node_of $portid
		117
		118	Extracts and returns the noderef from a portid or a noderef.
		119
		120	=item $SELF
		121
		122	Contains the current port id while executing C<rcv> callbacks or C<psub>
		123	blocks.
		124
		125	=item SELF, %SELF, @SELF...
		126
		127	Due to some quirks in how perl exports variables, it is impossible to
		128	just export C<$SELF>, all the symbols called C<SELF> are exported by this
		129	module, but only C<$SELF> is currently used.
99		130
100	=item snd $portid, type => @data	131	=item snd $portid, type => @data
101		132
102	=item snd $portid, @msg	133	=item snd $portid, @msg
103		134
…		…
117	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
118	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
119	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
120	node, anything can be passed.	151	node, anything can be passed.
121		152
122	=item $local_port = create_port	153	=item kil $portid[, @reason]
123		154
124	Create a new local port object. See the next section for allowed methods.	155	Kill the specified port with the given C<@reason>.
125		156
126	=cut	157	If no C<@reason> is specified, then the port is killed "normally" (linked
		158	ports will not be kileld, or even notified).
127		159
128	sub create_port {	160	Otherwise, linked ports get killed with the same reason (second form of
129	my $id = "$AnyEvent::MP::Base::UNIQ." . ++$AnyEvent::MP::Base::ID;	161	C<mon>, see below).
130		162
131	my $self = bless {	163	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
132	id => "$NODE#$id",	164	will be reported as reason C<< die => $@ >>.
133	names => [$id],
134	}, "AnyEvent::MP::Port";
135		165
136	$AnyEvent::MP::Base::PORT{$id} = sub {	166	Transport/communication errors are reported as C<< transport_error =>
137	unshift @_, $self;	167	$message >>.
138		168
139	for (@{ $self->{rc0}{$_[1]} }) {	169	=item $guard = mon $portid, $cb->(@reason)
140	$_ && &{$_->[0]}	170
141	&& undef $_;	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, $self => "restart";
		199
		200	=cut
		201
		202	sub mon {
		203	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
		204
		205	my $node = $NODE{$noderef} \|\| add_node $noderef;
		206
		207	#TODO: ports must not be references
		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 @_ };
142	}	217	}
		218	}
143		219
144	for (@{ $self->{rcv}{$_[1]} }) {	220	$node->monitor ($port, $cb);
145	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	221
146	&& &{$_->[0]}	222	defined wantarray
147	&& undef $_;	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;
148	}	239	});
		240	});
149		241
150	for (@{ $self->{any} }) {	242	=cut
151	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	243
152	&& &{$_->[0]}	244	sub mon_guard {
153	&& undef $_;	245	my ($port, @refs) = @_;
154	}	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;
155	};	280	};
156		281
157	$self	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
158	}	330	}
159		331
160	package AnyEvent::MP::Port;	332	=item reg $portid, $name
161		333
162	=back	334	Registers the given port under the name C<$name>. If the name already
		335	exists it is replaced.
163		336
164	=head1 METHODS FOR PORT OBJECTS	337	A port can only be registered under one well known name.
165		338
166	=over 4	339	A port automatically becomes unregistered when it is killed.
167		340
168	=item "$port"
169
170	A port object stringifies to its port ID, so can be used directly for
171	C<snd> operations.
172
173	=cut	341	=cut
174		342
175	use overload	343	sub reg(@) {
176	'""' => sub { $_[0]{id} },	344	my ($portid, $name) = @_;
177	fallback => 1;
178		345
179	=item $port->rcv (type => $callback->($port, @msg))	346	$REG{$name} = $portid;
		347	}
180		348
181	=item $port->rcv ($smartmatch => $callback->($port, @msg))	349	=item rcv $portid, tagstring => $callback->(@msg), ...
182		350
		351	=item rcv $portid, $smartmatch => $callback->(@msg), ...
		352
183	=item $port->rcv ([$smartmatch...] => $callback->($port, @msg))	353	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
184		354
185	Register a callback on the given port.	355	Register callbacks to be called on matching messages on the given port.
186		356
187	The callback has to return a true value when its work is done, after	357	The callback has to return a true value when its work is done, after
188	which is will be removed, or a false value in which case it will stay	358	which is will be removed, or a false value in which case it will stay
189	registered.	359	registered.
190		360
		361	The global C<$SELF> (exported by this module) contains C<$portid> while
		362	executing the callback.
		363
		364	Runtime errors wdurign callback execution will result in the port being
		365	C<kil>ed.
		366
191	If the match is an array reference, then it will be matched against the	367	If the match is an array reference, then it will be matched against the
192	first elements of the message, otherwise only the first element is being	368	first elements of the message, otherwise only the first element is being
193	matched.	369	matched.
194		370
195	Any element in the match that is specified as C<_any_> (a function	371	Any element in the match that is specified as C<_any_> (a function
…		…
200	also the most efficient match (by far).	376	also the most efficient match (by far).
201		377
202	=cut	378	=cut
203		379
204	sub rcv($@) {	380	sub rcv($@) {
205	my ($self, $match, $cb) = @_;	381	my ($noderef, $port) = split /#/, shift, 2;
206		382
		383	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		384	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
		385
		386	my $self = $PORT_DATA{$port}
		387	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
		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
207	if (!ref $match) {	395	if (!ref $match) {
208	push @{ $self->{rc0}{$match} }, [$cb];	396	push @{ $self->{rc0}{$match} }, [$cb];
209	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	397	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
210	my ($type, @match) = @$match;	398	my ($type, @match) = @$match;
211	@match	399	@match
212	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	400	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
213	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	401	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
214	} else {	402	} else {
215	push @{ $self->{any} }, [$cb, $match];	403	push @{ $self->{any} }, [$cb, $match];
		404	}
216	}	405	}
217	}	406	}
218		407
219	=item $port->register ($name)	408	=item $closure = psub { BLOCK }
220		409
221	Registers the given port under the well known name C<$name>. If the name	410	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
222	already exists it is replaced.	411	closure is executed, sets up the environment in the same way as in C<rcv>
		412	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
223		413
224	A port can only be registered under one well known name.	414	This is useful when you register callbacks from C<rcv> callbacks:
225		415
226	=cut	416	rcv delayed_reply => sub {
		417	my ($delay, @reply) = @_;
		418	my $timer = AE::timer $delay, 0, psub {
		419	snd @reply, $SELF;
		420	};
		421	};
227		422
228	sub register {	423	=cut
229	my ($self, $name) = @_;
230		424
231	$self->{wkname} = $name;	425	sub psub(&) {
232	$AnyEvent::MP::Base::WKP{$name} = "$self";	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	}
		443	}
233	}	444	}
234		445
235	=item $port->destroy
236
237	Explicitly destroy/remove/nuke/vaporise the port.
238
239	Ports are normally kept alive by there mere existance alone, and need to
240	be destroyed explicitly.
241
242	=cut
243
244	sub destroy {
245	my ($self) = @_;
246
247	delete $AnyEvent::MP::Base::WKP{ $self->{wkname} };
248
249	delete $AnyEvent::MP::Base::PORT{$_}
250	for @{ $self->{names} };
251	}
252
253	=back	446	=back
254		447
255	=head1 FUNCTIONS FOR NODES	448	=head1 FUNCTIONS FOR NODES
256		449
257	=over 4	450	=over 4
258
259	=item mon $noderef, $callback->($noderef, $status, $)
260
261	Monitors the given noderef.
262		451
263	=item become_public endpoint...	452	=item become_public endpoint...
264		453
265	Tells the node to become a public node, i.e. reachable from other nodes.	454	Tells the node to become a public node, i.e. reachable from other nodes.
266		455
…		…
286		475
287	=over 4	476	=over 4
288		477
289	=cut	478	=cut
290		479
291	=item wkp => $name, @reply	480	=item lookup => $name, @reply
292		481
293	Replies with the port ID of the specified well-known port, or C<undef>.	482	Replies with the port ID of the specified well-known port, or C<undef>.
294		483
295	=item devnull => ...	484	=item devnull => ...
296		485
…		…
319	snd $NODE, time => $myport, timereply => 1, 2;	508	snd $NODE, time => $myport, timereply => 1, 2;
320	# => snd $myport, timereply => 1, 2, <time>	509	# => snd $myport, timereply => 1, 2, <time>
321		510
322	=back	511	=back
323		512
		513	=head1 AnyEvent::MP vs. Distributed Erlang
		514
		515	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node
		516	== aemp node, erlang process == aemp port), so many of the documents and
		517	programming techniques employed by erlang apply to AnyEvent::MP. Here is a
		518	sample:
		519
		520	http://www.erlang.se/doc/programming_rules.shtml
		521	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
		522	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
		523	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
		524
		525	Despite the similarities, there are also some important differences:
		526
		527	=over 4
		528
		529	=item * Node references contain the recipe on how to contact them.
		530
		531	Erlang relies on special naming and DNS to work everywhere in the
		532	same way. AEMP relies on each node knowing it's own address(es), with
		533	convenience functionality.
		534
		535	This means that AEMP requires a less tightly controlled environment at the
		536	cost of longer node references and a slightly higher management overhead.
		537
		538	=item * Erlang uses processes and a mailbox, AEMP does not queue.
		539
		540	Erlang uses processes that selctively receive messages, and therefore
		541	needs a queue. AEMP is event based, queuing messages would serve no useful
		542	purpose.
		543
		544	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).
		545
		546	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
		547
		548	Sending messages in erlang is synchronous and blocks the process. AEMP
		549	sends are immediate, connection establishment is handled in the
		550	background.
		551
		552	=item * Erlang can silently lose messages, AEMP cannot.
		553
		554	Erlang makes few guarantees on messages delivery - messages can get lost
		555	without any of the processes realising it (i.e. you send messages a, b,
		556	and c, and the other side only receives messages a and c).
		557
		558	AEMP guarantees correct ordering, and the guarantee that there are no
		559	holes in the message sequence.
		560
		561	=item * In erlang, processes can be declared dead and later be found to be
		562	alive.
		563
		564	In erlang it can happen that a monitored process is declared dead and
		565	linked processes get killed, but later it turns out that the process is
		566	still alive - and can receive messages.
		567
		568	In AEMP, when port monitoring detects a port as dead, then that port will
		569	eventually be killed - it cannot happen that a node detects a port as dead
		570	and then later sends messages to it, finding it is still alive.
		571
		572	=item * Erlang can send messages to the wrong port, AEMP does not.
		573
		574	In erlang it is quite possible that a node that restarts reuses a process
		575	ID known to other nodes for a completely different process, causing
		576	messages destined for that process to end up in an unrelated process.
		577
		578	AEMP never reuses port IDs, so old messages or old port IDs floating
		579	around in the network will not be sent to an unrelated port.
		580
		581	=item * Erlang uses unprotected connections, AEMP uses secure
		582	authentication and can use TLS.
		583
		584	AEMP can use a proven protocol - SSL/TLS - to protect connections and
		585	securely authenticate nodes.
		586
		587	=back
		588
324	=head1 SEE ALSO	589	=head1 SEE ALSO
325		590
326	L<AnyEvent>.	591	L<AnyEvent>.
327		592
328	=head1 AUTHOR	593	=head1 AUTHOR

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.8 by root, Sun Aug 2 14:44:37 2009 UTC vs. Revision 1.27 by root, Tue Aug 4 22:13:45 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.8 by root, Sun Aug 2 14:44:37 2009 UTC vs.
Revision 1.27 by root, Tue Aug 4 22:13:45 2009 UTC