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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.32 by root, Wed Aug 5 19:58:46 2009 UTC vs.
Revision 1.35 by root, Thu Aug 6 10:21:48 2009 UTC

…		…
22	snd $port2, ping => $port1;	22	snd $port2, ping => $port1;
23		23
24	# more, smarter, matches (_any_ is exported by this module)	24	# more, smarter, matches (_any_ is exported by this module)
25	rcv $port, [child_died => $pid] => sub { ...	25	rcv $port, [child_died => $pid] => sub { ...
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
		27
		28	# linking two ports, so they both crash together
		29	lnk $port1, $port2;
		30
		31	# monitoring
		32	mon $port, $cb->(@msg) # callback is invoked on death
		33	mon $port, $otherport # kill otherport on abnormal death
		34	mon $port, $otherport, @msg # send message on death
27		35
28	=head1 DESCRIPTION	36	=head1 DESCRIPTION
29		37
30	This module (-family) implements a simple message passing framework.	38	This module (-family) implements a simple message passing framework.
31		39
…		…
123	The C<NODE> function returns, and the C<$NODE> variable contains	131	The C<NODE> function returns, and the C<$NODE> variable contains
124	the noderef of the local node. The value is initialised by a call	132	the noderef of the local node. The value is initialised by a call
125	to C<become_public> or C<become_slave>, after which all local port	133	to C<become_public> or C<become_slave>, after which all local port
126	identifiers become invalid.	134	identifiers become invalid.
127		135
128	=item $noderef = node_of $portid	136	=item $noderef = node_of $port
129		137
130	Extracts and returns the noderef from a portid or a noderef.	138	Extracts and returns the noderef from a portid or a noderef.
		139
		140	=item initialise_node $noderef, $seednode, $seednode...
		141
		142	=item initialise_node "slave/", $master, $master...
		143
		144	Before a node can talk to other nodes on the network it has to initialise
		145	itself - the minimum a node needs to know is it's own name, and optionally
		146	it should know the noderefs of some other nodes in the network.
		147
		148	This function initialises a node - it must be called exactly once (or
		149	never) before calling other AnyEvent::MP functions.
		150
		151	All arguments are noderefs, which can be either resolved or unresolved.
		152
		153	There are two types of networked nodes, public nodes and slave nodes:
		154
		155	=over 4
		156
		157	=item public nodes
		158
		159	For public nodes, C<$noderef> must either be a (possibly unresolved)
		160	noderef, in which case it will be resolved, or C<undef> (or missing), in
		161	which case the noderef will be guessed.
		162
		163	Afterwards, the node will bind itself on all endpoints and try to connect
		164	to all additional C<$seednodes> that are specified. Seednodes are optional
		165	and can be used to quickly bootstrap the node into an existing network.
		166
		167	=item slave nodes
		168
		169	When the C<$noderef> is the special string C<slave/>, then the node will
		170	become a slave node. Slave nodes cannot be contacted from outside and will
		171	route most of their traffic to the master node that they attach to.
		172
		173	At least one additional noderef is required: The node will try to connect
		174	to all of them and will become a slave attached to the first node it can
		175	successfully connect to.
		176
		177	=back
		178
		179	This function will block until all nodes have been resolved and, for slave
		180	nodes, until it has successfully established a connection to a master
		181	server.
		182
		183	Example: become a public node listening on the default node.
		184
		185	initialise_node;
		186
		187	Example: become a public node, and try to contact some well-known master
		188	servers to become part of the network.
		189
		190	initialise_node undef, "master1", "master2";
		191
		192	Example: become a public node listening on port C<4041>.
		193
		194	initialise_node 4041;
		195
		196	Example: become a public node, only visible on localhost port 4044.
		197
		198	initialise_node "locahost:4044";
		199
		200	Example: become a slave node to any of the specified master servers.
		201
		202	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
131		203
132	=item $cv = resolve_node $noderef	204	=item $cv = resolve_node $noderef
133		205
134	Takes an unresolved node reference that may contain hostnames and	206	Takes an unresolved node reference that may contain hostnames and
135	abbreviated IDs, resolves all of them and returns a resolved node	207	abbreviated IDs, resolves all of them and returns a resolved node
…		…
167		239
168	Due to some quirks in how perl exports variables, it is impossible to	240	Due to some quirks in how perl exports variables, it is impossible to
169	just export C<$SELF>, all the symbols called C<SELF> are exported by this	241	just export C<$SELF>, all the symbols called C<SELF> are exported by this
170	module, but only C<$SELF> is currently used.	242	module, but only C<$SELF> is currently used.
171		243
172	=item snd $portid, type => @data	244	=item snd $port, type => @data
173		245
174	=item snd $portid, @msg	246	=item snd $port, @msg
175		247
176	Send the given message to the given port ID, which can identify either	248	Send the given message to the given port ID, which can identify either
177	a local or a remote port, and can be either a string or soemthignt hat	249	a local or a remote port, and can be either a string or soemthignt hat
178	stringifies a sa port ID (such as a port object :).	250	stringifies a sa port ID (such as a port object :).
179		251
…		…
195		267
196	Create a new local port object that can be used either as a pattern	268	Create a new local port object that can be used either as a pattern
197	matching port ("full port") or a single-callback port ("miniport"),	269	matching port ("full port") or a single-callback port ("miniport"),
198	depending on how C<rcv> callbacks are bound to the object.	270	depending on how C<rcv> callbacks are bound to the object.
199		271
200	=item $portid = port { my @msg = @_; $finished }	272	=item $port = port { my @msg = @_; $finished }
201		273
202	Creates a "mini port", that is, a very lightweight port without any	274	Creates a "miniport", that is, a very lightweight port without any pattern
203	pattern matching behind it, and returns its ID.	275	matching behind it, and returns its ID. Semantically the same as creating
		276	a port and calling C<rcv $port, $callback> on it.
204		277
205	The block will be called for every message received on the port. When the	278	The block will be called for every message received on the port. When the
206	callback returns a true value its job is considered "done" and the port	279	callback returns a true value its job is considered "done" and the port
207	will be destroyed. Otherwise it will stay alive.	280	will be destroyed. Otherwise it will stay alive.
208		281
…		…
215	snd $otherport, reply => $port;	288	snd $otherport, reply => $port;
216	};	289	};
217		290
218	=cut	291	=cut
219		292
		293	sub rcv($@);
		294
220	sub port(;&) {	295	sub port(;&) {
221	my $id = "$UNIQ." . $ID++;	296	my $id = "$UNIQ." . $ID++;
222	my $port = "$NODE#$id";	297	my $port = "$NODE#$id";
223		298
224	if (@_) {	299	if (@_) {
		300	rcv $port, shift;
		301	} else {
		302	$PORT{$id} = sub { }; # nop
		303	}
		304
		305	$port
		306	}
		307
		308	=item reg $port, $name
		309
		310	Registers the given port under the name C<$name>. If the name already
		311	exists it is replaced.
		312
		313	A port can only be registered under one well known name.
		314
		315	A port automatically becomes unregistered when it is killed.
		316
		317	=cut
		318
		319	sub reg(@) {
		320	my ($port, $name) = @_;
		321
		322	$REG{$name} = $port;
		323	}
		324
		325	=item rcv $port, $callback->(@msg)
		326
		327	Replaces the callback on the specified miniport (after converting it to
		328	one if required).
		329
		330	=item rcv $port, tagstring => $callback->(@msg), ...
		331
		332	=item rcv $port, $smartmatch => $callback->(@msg), ...
		333
		334	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		335
		336	Register callbacks to be called on matching messages on the given full
		337	port (after converting it to one if required).
		338
		339	The callback has to return a true value when its work is done, after
		340	which is will be removed, or a false value in which case it will stay
		341	registered.
		342
		343	The global C<$SELF> (exported by this module) contains C<$port> while
		344	executing the callback.
		345
		346	Runtime errors wdurign callback execution will result in the port being
		347	C<kil>ed.
		348
		349	If the match is an array reference, then it will be matched against the
		350	first elements of the message, otherwise only the first element is being
		351	matched.
		352
		353	Any element in the match that is specified as C<_any_> (a function
		354	exported by this module) matches any single element of the message.
		355
		356	While not required, it is highly recommended that the first matching
		357	element is a string identifying the message. The one-string-only match is
		358	also the most efficient match (by far).
		359
		360	=cut
		361
		362	sub rcv($@) {
		363	my $port = shift;
		364	my ($noderef, $portid) = split /#/, $port, 2;
		365
		366	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		367	or Carp::croak "$port: rcv can only be called on local ports, caught";
		368
		369	if (@_ == 1) {
225	my $cb = shift;	370	my $cb = shift;
		371	delete $PORT_DATA{$portid};
226	$PORT{$id} = sub {	372	$PORT{$portid} = sub {
227	local $SELF = $port;	373	local $SELF = $port;
228	eval {	374	eval {
229	&$cb	375	&$cb
230	and kil $id;	376	and kil $port;
231	};	377	};
232	_self_die if $@;	378	_self_die if $@;
233	};	379	};
234	} else {	380	} else {
		381	my $self = $PORT_DATA{$portid} \|\|= do {
235	my $self = bless {	382	my $self = bless {
236	id => "$NODE#$id",	383	id => $port,
237	}, "AnyEvent::MP::Port";	384	}, "AnyEvent::MP::Port";
238		385
239	$PORT_DATA{$id} = $self;
240	$PORT{$id} = sub {	386	$PORT{$portid} = sub {
241	local $SELF = $port;	387	local $SELF = $port;
242		388
243	eval {	389	eval {
244	for (@{ $self->{rc0}{$_[0]} }) {	390	for (@{ $self->{rc0}{$_[0]} }) {
245	$_ && &{$_->[0]}	391	$_ && &{$_->[0]}
246	&& undef $_;	392	&& undef $_;
247	}	393	}
248		394
249	for (@{ $self->{rcv}{$_[0]} }) {	395	for (@{ $self->{rcv}{$_[0]} }) {
250	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	396	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
251	&& &{$_->[0]}	397	&& &{$_->[0]}
252	&& undef $_;	398	&& undef $_;
253	}	399	}
254		400
255	for (@{ $self->{any} }) {	401	for (@{ $self->{any} }) {
256	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	402	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
257	&& &{$_->[0]}	403	&& &{$_->[0]}
258	&& undef $_;	404	&& undef $_;
		405	}
259	}	406	};
		407	_self_die if $@;
260	};	408	};
261	_self_die if $@;	409
		410	$self
262	};	411	};
263	}
264		412
265	$port
266	}
267
268	=item reg $portid, $name
269
270	Registers the given port under the name C<$name>. If the name already
271	exists it is replaced.
272
273	A port can only be registered under one well known name.
274
275	A port automatically becomes unregistered when it is killed.
276
277	=cut
278
279	sub reg(@) {
280	my ($portid, $name) = @_;
281
282	$REG{$name} = $portid;
283	}
284
285	=item rcv $portid, $callback->(@msg)
286
287	Replaces the callback on the specified miniport (or newly created port
288	object, see C<port>). Full ports are configured with the following calls:
289
290	=item rcv $portid, tagstring => $callback->(@msg), ...
291
292	=item rcv $portid, $smartmatch => $callback->(@msg), ...
293
294	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
295
296	Register callbacks to be called on matching messages on the given full
297	port (or newly created port).
298
299	The callback has to return a true value when its work is done, after
300	which is will be removed, or a false value in which case it will stay
301	registered.
302
303	The global C<$SELF> (exported by this module) contains C<$portid> while
304	executing the callback.
305
306	Runtime errors wdurign callback execution will result in the port being
307	C<kil>ed.
308
309	If the match is an array reference, then it will be matched against the
310	first elements of the message, otherwise only the first element is being
311	matched.
312
313	Any element in the match that is specified as C<_any_> (a function
314	exported by this module) matches any single element of the message.
315
316	While not required, it is highly recommended that the first matching
317	element is a string identifying the message. The one-string-only match is
318	also the most efficient match (by far).
319
320	=cut
321
322	sub rcv($@) {
323	my $portid = shift;
324	my ($noderef, $port) = split /#/, $port, 2;
325
326	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
327	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
328
329	my $self = $PORT_DATA{$port}
330	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
331
332	"AnyEvent::MP::Port" eq ref $self	413	"AnyEvent::MP::Port" eq ref $self
333	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";	414	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
334		415
335	while (@_) {	416	while (@_) {
336	my ($match, $cb) = splice @_, 0, 2;	417	my ($match, $cb) = splice @_, 0, 2;
337		418
338	if (!ref $match) {	419	if (!ref $match) {
339	push @{ $self->{rc0}{$match} }, [$cb];	420	push @{ $self->{rc0}{$match} }, [$cb];
340	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	421	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
341	my ($type, @match) = @$match;	422	my ($type, @match) = @$match;
342	@match	423	@match
343	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	424	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
344	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	425	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
345	} else {	426	} else {
346	push @{ $self->{any} }, [$cb, $match];	427	push @{ $self->{any} }, [$cb, $match];
		428	}
347	}	429	}
348	}	430	}
349		431
350	$portid	432	$port
351	}	433	}
352		434
353	=item $closure = psub { BLOCK }	435	=item $closure = psub { BLOCK }
354		436
355	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	437	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
…		…
386	$res	468	$res
387	}	469	}
388	}	470	}
389	}	471	}
390		472
391	=item $guard = mon $portid, $cb->(@reason)	473	=item $guard = mon $port, $cb->(@reason)
392		474
393	=item $guard = mon $portid, $otherport	475	=item $guard = mon $port, $otherport
394		476
395	=item $guard = mon $portid, $otherport, @msg	477	=item $guard = mon $port, $otherport, @msg
396		478
397	Monitor the given port and do something when the port is killed.	479	Monitor the given port and do something when the port is killed.
398		480
399	In the first form, the callback is simply called with any number	481	In the first form, the callback is simply called with any number
400	of C<@reason> elements (no @reason means that the port was deleted	482	of C<@reason> elements (no @reason means that the port was deleted
…		…
478	mon $port2, $port1;	560	mon $port2, $port1;
479		561
480	It means that if either one is killed abnormally, the other one gets	562	It means that if either one is killed abnormally, the other one gets
481	killed as well.	563	killed as well.
482		564
483	=item kil $portid[, @reason]	565	=item kil $port[, @reason]
484		566
485	Kill the specified port with the given C<@reason>.	567	Kill the specified port with the given C<@reason>.
486		568
487	If no C<@reason> is specified, then the port is killed "normally" (linked	569	If no C<@reason> is specified, then the port is killed "normally" (linked
488	ports will not be kileld, or even notified).	570	ports will not be kileld, or even notified).
…		…
493	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	575	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
494	will be reported as reason C<< die => $@ >>.	576	will be reported as reason C<< die => $@ >>.
495		577
496	Transport/communication errors are reported as C<< transport_error =>	578	Transport/communication errors are reported as C<< transport_error =>
497	$message >>.	579	$message >>.
498
499	=back
500
501	=head1 FUNCTIONS FOR NODES
502
503	=over 4
504
505	=item become_public $noderef
506
507	Tells the node to become a public node, i.e. reachable from other nodes.
508
509	The first argument is the (unresolved) node reference of the local node
510	(if missing then the empty string is used).
511
512	It is quite common to not specify anything, in which case the local node
513	tries to listen on the default port, or to only specify a port number, in
514	which case AnyEvent::MP tries to guess the local addresses.
515
516	=cut
517		580
518	=back	581	=back
519		582
520	=head1 NODE MESSAGES	583	=head1 NODE MESSAGES
521		584
…		…
563		626
564	=back	627	=back
565		628
566	=head1 AnyEvent::MP vs. Distributed Erlang	629	=head1 AnyEvent::MP vs. Distributed Erlang
567		630
568	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node	631	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
569	== aemp node, erlang process == aemp port), so many of the documents and	632	== aemp node, Erlang process == aemp port), so many of the documents and
570	programming techniques employed by erlang apply to AnyEvent::MP. Here is a	633	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
571	sample:	634	sample:
572		635
573	http://www.erlang.se/doc/programming_rules.shtml	636	http://www.Erlang.se/doc/programming_rules.shtml
574	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	637	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
575	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6	638	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
576	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5	639	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
577		640
578	Despite the similarities, there are also some important differences:	641	Despite the similarities, there are also some important differences:
579		642
580	=over 4	643	=over 4
581		644
…		…
592		655
593	Erlang uses processes that selctively receive messages, and therefore	656	Erlang uses processes that selctively receive messages, and therefore
594	needs a queue. AEMP is event based, queuing messages would serve no useful	657	needs a queue. AEMP is event based, queuing messages would serve no useful
595	purpose.	658	purpose.
596		659
597	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).	660	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
598		661
599	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	662	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
600		663
601	Sending messages in erlang is synchronous and blocks the process. AEMP	664	Sending messages in Erlang is synchronous and blocks the process. AEMP
602	sends are immediate, connection establishment is handled in the	665	sends are immediate, connection establishment is handled in the
603	background.	666	background.
604		667
605	=item * Erlang can silently lose messages, AEMP cannot.	668	=item * Erlang can silently lose messages, AEMP cannot.
606		669
…		…
609	and c, and the other side only receives messages a and c).	672	and c, and the other side only receives messages a and c).
610		673
611	AEMP guarantees correct ordering, and the guarantee that there are no	674	AEMP guarantees correct ordering, and the guarantee that there are no
612	holes in the message sequence.	675	holes in the message sequence.
613		676
614	=item * In erlang, processes can be declared dead and later be found to be	677	=item * In Erlang, processes can be declared dead and later be found to be
615	alive.	678	alive.
616		679
617	In erlang it can happen that a monitored process is declared dead and	680	In Erlang it can happen that a monitored process is declared dead and
618	linked processes get killed, but later it turns out that the process is	681	linked processes get killed, but later it turns out that the process is
619	still alive - and can receive messages.	682	still alive - and can receive messages.
620		683
621	In AEMP, when port monitoring detects a port as dead, then that port will	684	In AEMP, when port monitoring detects a port as dead, then that port will
622	eventually be killed - it cannot happen that a node detects a port as dead	685	eventually be killed - it cannot happen that a node detects a port as dead
623	and then later sends messages to it, finding it is still alive.	686	and then later sends messages to it, finding it is still alive.
624		687
625	=item * Erlang can send messages to the wrong port, AEMP does not.	688	=item * Erlang can send messages to the wrong port, AEMP does not.
626		689
627	In erlang it is quite possible that a node that restarts reuses a process	690	In Erlang it is quite possible that a node that restarts reuses a process
628	ID known to other nodes for a completely different process, causing	691	ID known to other nodes for a completely different process, causing
629	messages destined for that process to end up in an unrelated process.	692	messages destined for that process to end up in an unrelated process.
630		693
631	AEMP never reuses port IDs, so old messages or old port IDs floating	694	AEMP never reuses port IDs, so old messages or old port IDs floating
632	around in the network will not be sent to an unrelated port.	695	around in the network will not be sent to an unrelated port.
…		…
638	securely authenticate nodes.	701	securely authenticate nodes.
639		702
640	=item * The AEMP protocol is optimised for both text-based and binary	703	=item * The AEMP protocol is optimised for both text-based and binary
641	communications.	704	communications.
642		705
643	The AEMP protocol, unlike the erlang protocol, supports both	706	The AEMP protocol, unlike the Erlang protocol, supports both
644	language-independent text-only protocols (good for debugging) and binary,	707	language-independent text-only protocols (good for debugging) and binary,
645	language-specific serialisers (e.g. Storable).	708	language-specific serialisers (e.g. Storable).
646		709
647	It has also been carefully designed to be implementable in other languages	710	It has also been carefully designed to be implementable in other languages
648	with a minimum of work while gracefully degrading fucntionality to make the	711	with a minimum of work while gracefully degrading fucntionality to make the
649	protocol simple.	712	protocol simple.
650		713
		714	=item * AEMP has more flexible monitoring options than Erlang.
		715
		716	In Erlang, you can chose to receive I<all> exit signals as messages
		717	or I<none>, there is no in-between, so monitoring single processes is
		718	difficult to implement. Monitoring in AEMP is more flexible than in
		719	Erlang, as one can choose between automatic kill, exit message or callback
		720	on a per-process basis.
		721
		722	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.
		723
		724	Monitoring in Erlang is not an indicator of process death/crashes,
		725	as linking is (except linking is unreliable in Erlang). In AEMP, the
		726	semantics of monitoring and linking are identical, linking is simply
		727	two-way monitoring with automatic kill.
		728
651	=back	729	=back
652		730
653	=head1 SEE ALSO	731	=head1 SEE ALSO
654		732
655	L<AnyEvent>.	733	L<AnyEvent>.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.32 by root, Wed Aug 5 19:58:46 2009 UTC vs. Revision 1.35 by root, Thu Aug 6 10:21:48 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.32 by root, Wed Aug 5 19:58:46 2009 UTC vs.
Revision 1.35 by root, Thu Aug 6 10:21:48 2009 UTC