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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.127 by root, Sat Mar 3 20:35:10 2012 UTC vs.
Revision 1.137 by root, Wed Mar 21 23:48:39 2012 UTC

…		…
35	# destroy a port again	35	# destroy a port again
36	kil $port; # "normal" kill	36	kil $port; # "normal" kill
37	kil $port, my_error => "everything is broken"; # error kill	37	kil $port, my_error => "everything is broken"; # error kill
38		38
39	# monitoring	39	# monitoring
40	mon $localport, $cb->(@msg) # callback is invoked on death	40	mon $port, $cb->(@msg) # callback is invoked on death
41	mon $localport, $otherport # kill otherport on abnormal death	41	mon $port, $localport # kill localport on abnormal death
42	mon $localport, $otherport, @msg # send message on death	42	mon $port, $localport, @msg # send message on death
43		43
44	# temporarily execute code in port context	44	# temporarily execute code in port context
45	peval $port, sub { die "kill the port!" };	45	peval $port, sub { die "kill the port!" };
46		46
47	# execute callbacks in $SELF port context	47	# execute callbacks in $SELF port context
…		…
197	NODE $NODE *SELF node_of after	197	NODE $NODE *SELF node_of after
198	configure	198	configure
199	snd rcv mon mon_guard kil psub peval spawn cal	199	snd rcv mon mon_guard kil psub peval spawn cal
200	port	200	port
201	db_set db_del db_reg	201	db_set db_del db_reg
		202	db_mon db_family db_keys db_values
202	);	203	);
203		204
204	our $SELF;	205	our $SELF;
205		206
206	sub _self_die() {	207	sub _self_die() {
…		…
246		247
247	IF true, then the values specified in the C<configure> will take	248	IF true, then the values specified in the C<configure> will take
248	precedence over any values configured via the rc file. The default is for	249	precedence over any values configured via the rc file. The default is for
249	the rc file to override any options specified in the program.	250	the rc file to override any options specified in the program.
250		251
251	=item secure => $pass->($nodeid)	252	=item secure => $pass->(@msg)
252		253
253	In addition to specifying a boolean, you can specify a code reference that	254	In addition to specifying a boolean, you can specify a code reference that
254	is called for every remote execution attempt - the execution request is	255	is called for every code execution attempt - the execution request is
255	granted iff the callback returns a true value.	256	granted iff the callback returns a true value.
		257
		258	Most of the time the callback should look only at
		259	C<$AnyEvent::MP::Kernel::SRCNODE> to make a decision, and not at the
		260	actual message (which can be about anything, and is mostly provided for
		261	diagnostic purposes).
256		262
257	See F<semp setsecure> for more info.	263	See F<semp setsecure> for more info.
258		264
259	=back	265	=back
260		266
…		…
397		403
398	=cut	404	=cut
399		405
400	sub rcv($@);	406	sub rcv($@);
401		407
402	sub _kilme {	408	my $KILME = sub {
403	die "received message on port without callback";	409	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
404	}	410	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		411	};
405		412
406	sub port(;&) {	413	sub port(;&) {
407	my $id = $UNIQ . ++$ID;	414	my $id = $UNIQ . ++$ID;
408	my $port = "$NODE#$id";	415	my $port = "$NODE#$id";
409		416
410	rcv $port, shift \|\| \&_kilme;	417	rcv $port, shift \|\| $KILME;
411		418
412	$port	419	$port
413	}	420	}
414		421
415	=item rcv $local_port, $callback->(@msg)	422	=item rcv $local_port, $callback->(@msg)
…		…
420		427
421	The global C<$SELF> (exported by this module) contains C<$port> while	428	The global C<$SELF> (exported by this module) contains C<$port> while
422	executing the callback. Runtime errors during callback execution will	429	executing the callback. Runtime errors during callback execution will
423	result in the port being C<kil>ed.	430	result in the port being C<kil>ed.
424		431
425	The default callback received all messages not matched by a more specific	432	The default callback receives all messages not matched by a more specific
426	C<tag> match.	433	C<tag> match.
427		434
428	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	435	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
429		436
430	Register (or replace) callbacks to be called on messages starting with the	437	Register (or replace) callbacks to be called on messages starting with the
…		…
731	will be reported as reason C<< die => $@ >>.	738	will be reported as reason C<< die => $@ >>.
732		739
733	Transport/communication errors are reported as C<< transport_error =>	740	Transport/communication errors are reported as C<< transport_error =>
734	$message >>.	741	$message >>.
735		742
736	=cut	743	Common idioms:
		744
		745	# silently remove yourself, do not kill linked ports
		746	kil $SELF;
		747
		748	# report a failure in some detail
		749	kil $SELF, failure_mode_1 => "it failed with too high temperature";
		750
		751	# do not waste much time with killing, just die when something goes wrong
		752	open my $fh, "<file"
		753	or die "file: $!";
737		754
738	=item $port = spawn $node, $initfunc[, @initdata]	755	=item $port = spawn $node, $initfunc[, @initdata]
739		756
740	Creates a port on the node C<$node> (which can also be a port ID, in which	757	Creates a port on the node C<$node> (which can also be a port ID, in which
741	case it's the node where that port resides).	758	case it's the node where that port resides).
…		…
833	ref $action[0]	850	ref $action[0]
834	? $action[0]()	851	? $action[0]()
835	: snd @action;	852	: snd @action;
836	};	853	};
837	}	854	}
		855
		856	#=item $cb2 = timeout $seconds, $cb[, @args]
838		857
839	=item cal $port, @msg, $callback[, $timeout]	858	=item cal $port, @msg, $callback[, $timeout]
840		859
841	A simple form of RPC - sends a message to the given C<$port> with the	860	A simple form of RPC - sends a message to the given C<$port> with the
842	given contents (C<@msg>), but adds a reply port to the message.	861	given contents (C<@msg>), but adds a reply port to the message.
…		…
891	=back	910	=back
892		911
893	=head1 DISTRIBUTED DATABASE	912	=head1 DISTRIBUTED DATABASE
894		913
895	AnyEvent::MP comes with a simple distributed database. The database will	914	AnyEvent::MP comes with a simple distributed database. The database will
896	be mirrored asynchronously at all global nodes. Other nodes bind to one of	915	be mirrored asynchronously on all global nodes. Other nodes bind to one
897	the global nodes for their needs.	916	of the global nodes for their needs. Every node has a "local database"
		917	which contains all the values that are set locally. All local databases
		918	are merged together to form the global database, which can be queried.
898		919
899	The database consists of a two-level hash - a hash contains a hash which	920	The database structure is that of a two-level hash - the database hash
900	contains values.	921	contains hashes which contain values, similarly to a perl hash of hashes,
		922	i.e.:
		923
		924	$DATABASE{$family}{$subkey} = $value
901		925
902	The top level hash key is called "family", and the second-level hash key	926	The top level hash key is called "family", and the second-level hash key
903	is called "subkey" or simply "key".	927	is called "subkey" or simply "key".
904		928
905	The family must be alphanumeric, i.e. start with a letter and consist	929	The family must be alphanumeric, i.e. start with a letter and consist
…		…
910	with the name of the application or module using it.	934	with the name of the application or module using it.
911		935
912	The subkeys must be non-empty strings, with no further restrictions.	936	The subkeys must be non-empty strings, with no further restrictions.
913		937
914	The values should preferably be strings, but other perl scalars should	938	The values should preferably be strings, but other perl scalars should
915	work as well (such as undef, arrays and hashes).	939	work as well (such as C<undef>, arrays and hashes).
916		940
917	Every database entry is owned by one node - adding the same family/subkey	941	Every database entry is owned by one node - adding the same family/subkey
918	combination on multiple nodes will not cause discomfort for AnyEvent::MP,	942	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
919	but the result might be nondeterministic, i.e. the key might have	943	but the result might be nondeterministic, i.e. the key might have
920	different values on different nodes.	944	different values on different nodes.
…		…
924	pools. For example, a worker port for image scaling might do this:	948	pools. For example, a worker port for image scaling might do this:
925		949
926	db_set my_image_scalers => $port;	950	db_set my_image_scalers => $port;
927		951
928	And clients looking for an image scaler will want to get the	952	And clients looking for an image scaler will want to get the
929	C<my_image_scalers> keys:	953	C<my_image_scalers> keys from time to time:
930		954
931	db_keys "my_image_scalers" => 60 => sub {	955	db_keys my_image_scalers => sub {
932	#d##TODO#	956	@ports = @{ $_[0] };
		957	};
		958
		959	Or better yet, they want to monitor the database family, so they always
		960	have a reasonable up-to-date copy:
		961
		962	db_mon my_image_scalers => sub {
		963	@ports = keys %{ $_[0] };
		964	};
		965
		966	In general, you can set or delete single subkeys, but query and monitor
		967	whole families only.
		968
		969	If you feel the need to monitor or query a single subkey, try giving it
		970	it's own family.
933		971
934	=over	972	=over
935		973
936	=item db_set $family => $subkey [=> $value]	974	=item $guard = db_set $family => $subkey [=> $value]
937		975
938	Sets (or replaces) a key to the database - if C<$value> is omitted,	976	Sets (or replaces) a key to the database - if C<$value> is omitted,
939	C<undef> is used instead.	977	C<undef> is used instead.
940		978
		979	When called in non-void context, C<db_set> returns a guard that
		980	automatically calls C<db_del> when it is destroyed.
		981
941	=item db_del $family => $subkey	982	=item db_del $family => $subkey...
942		983
943	Deletes a key from the database.	984	Deletes one or more subkeys from the database family.
944		985
945	=item $guard = db_reg $family => $subkey [=> $value]	986	=item $guard = db_reg $family => $port => $value
946		987
947	Sets the key on the database and returns a guard. When the guard is	988	=item $guard = db_reg $family => $port
948	destroyed, the key is deleted from the database. If C<$value> is missing,	989
949	then C<undef> is used.	990	=item $guard = db_reg $family
		991
		992	Registers a port in the given family and optionally returns a guard to
		993	remove it.
		994
		995	This function basically does the same as:
		996
		997	db_set $family => $port => $value
		998
		999	Except that the port is monitored and automatically removed from the
		1000	database family when it is kil'ed.
		1001
		1002	If C<$value> is missing, C<undef> is used. If C<$port> is missing, then
		1003	C<$SELF> is used.
		1004
		1005	This function is most useful to register a port in some port group (which
		1006	is just another name for a database family), and have it removed when the
		1007	port is gone. This works best when the port is a local port.
		1008
		1009	=cut
		1010
		1011	sub db_reg($$;$) {
		1012	my $family = shift;
		1013	my $port = @_ ? shift : $SELF;
		1014
		1015	my $clr = sub { db_del $family => $port };
		1016	mon $port, $clr;
		1017
		1018	db_set $family => $port => $_[0];
		1019
		1020	defined wantarray
		1021	and &Guard::guard ($clr)
		1022	}
		1023
		1024	=item db_family $family => $cb->(\%familyhash)
		1025
		1026	Queries the named database C<$family> and call the callback with the
		1027	family represented as a hash. You can keep and freely modify the hash.
		1028
		1029	=item db_keys $family => $cb->(\@keys)
		1030
		1031	Same as C<db_family>, except it only queries the family I<subkeys> and passes
		1032	them as array reference to the callback.
		1033
		1034	=item db_values $family => $cb->(\@values)
		1035
		1036	Same as C<db_family>, except it only queries the family I<values> and passes them
		1037	as array reference to the callback.
		1038
		1039	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)
		1040
		1041	Creates a monitor on the given database family. Each time a key is set
		1042	or or is deleted the callback is called with a hash containing the
		1043	database family and three lists of added, changed and deleted subkeys,
		1044	respectively. If no keys have changed then the array reference might be
		1045	C<undef> or even missing.
		1046
		1047	If not called in void context, a guard object is returned that, when
		1048	destroyed, stops the monitor.
		1049
		1050	The family hash reference and the key arrays belong to AnyEvent::MP and
		1051	B<must not be modified or stored> by the callback. When in doubt, make a
		1052	copy.
		1053
		1054	As soon as possible after the monitoring starts, the callback will be
		1055	called with the intiial contents of the family, even if it is empty,
		1056	i.e. there will always be a timely call to the callback with the current
		1057	contents.
		1058
		1059	It is possible that the callback is called with a change event even though
		1060	the subkey is already present and the value has not changed.
		1061
		1062	The monitoring stops when the guard object is destroyed.
		1063
		1064	Example: on every change to the family "mygroup", print out all keys.
		1065
		1066	my $guard = db_mon mygroup => sub {
		1067	my ($family, $a, $c, $d) = @_;
		1068	print "mygroup members: ", (join " ", keys %$family), "\n";
		1069	};
		1070
		1071	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1072
		1073	my $guard; $guard = db_mon My::Module::workers => sub {
		1074	my ($family, $a, $c, $d) = @_;
		1075	return unless %$family;
		1076	undef $guard;
		1077	print "My::Module::workers now nonempty\n";
		1078	};
		1079
		1080	Example: print all changes to the family "AnyRvent::Fantasy::Module".
		1081
		1082	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
		1083	my ($family, $a, $c, $d) = @_;
		1084
		1085	print "+$_=$family->{$_}\n" for @$a;
		1086	print "*$_=$family->{$_}\n" for @$c;
		1087	print "-$_=$family->{$_}\n" for @$d;
		1088	};
950		1089
951	=cut	1090	=cut
952		1091
953	=back	1092	=back
954		1093
…		…
1113	Keeping your messages simple, concentrating on data structures rather than	1252	Keeping your messages simple, concentrating on data structures rather than
1114	objects, will keep your messages clean, tidy and efficient.	1253	objects, will keep your messages clean, tidy and efficient.
1115		1254
1116	=back	1255	=back
1117		1256
		1257	=head1 PORTING FROM AnyEvent::MP VERSION 1.X
		1258
		1259	AEMP version 2 has three major incompatible changes compared to version 1:
		1260
		1261	=over 4
		1262
		1263	=item AnyEvent::MP::Global no longer has group management functions.
		1264
		1265	AnyEvent::MP now comes with a distributed database that is more
		1266	powerful. It's database families map closely to ports, but the API has
		1267	minor differences:
		1268
		1269	grp_reg $group, $port # old
		1270	db_reg $group, $port # new
		1271
		1272	$list = grp_get $group # old
		1273	db_keys $group, sub { my $list = shift } # new
		1274
		1275	grp_mon $group, $cb->(\@ports, $add, $del) # old
		1276	db_mon $group, $cb->(\%ports, $add, $change, $del) # new
		1277
		1278	C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get>
		1279	is no longer instant, because the local node might not have a copy of
		1280	the group. This can be partially remedied by using C<db_mon> to keep an
		1281	updated copy of the group:
		1282
		1283	my $local_group_copy;
		1284	db_mon $group => sub { $local_group_copy = shift };
		1285
		1286	# no keys %$local_group_copy always returns the most up-to-date
		1287	# list of ports in the group.
		1288
		1289	C<grp_mon> can almost be replaced by C<db_mon>:
		1290
		1291	db_mon $group => sub {
		1292	my ($ports, $add, $chg, $lde) = @_;
		1293	$ports = [keys %$ports];
		1294
		1295	# now $ports, $add and $del are the same as
		1296	# were originally passed by grp_mon.
		1297	...
		1298	};
		1299
		1300	=item Nodes not longer connect to all other nodes.
		1301
		1302	In AEMP 1.x, every node automatically loads the L<AnyEvent::MP::Global>
		1303	module, which in turn would create connections to all other nodes in the
		1304	network (helped by the seed nodes).
		1305
		1306	In version 2.x, global nodes still connect to all other global nodes, but
		1307	other nodes don't - now every node either is a global node itself, or
		1308	attaches itself to another global node.
		1309
		1310	If a node isn't a global node itself, then it attaches itself to one
		1311	of its seed nodes. If that seed node isn't a global node yet, it will
		1312	automatically be upgraded to a global node.
		1313
		1314	So in many cases, nothing needs to be changed - one just has to make sure
		1315	that all seed nodes are meshed together with the other seed nodes (as with
		1316	AEMP 1.x), and other nodes specify them as seed nodes.
		1317
		1318	Not opening a connection to every other node is usually an advantage,
		1319	except when you need the lower latency of an already established
		1320	connection. To ensure a node establishes a connection to another node,
		1321	you can monitor the node port (C<mon $node, ...>), which will attempt to
		1322	create the connection (And notify you when the connection fails).
		1323
		1324	=item Listener-less nodes are gone.
		1325
		1326	And are not coming back, at least not in their old form.
		1327
		1328	There are vague plans to implement some form of routing domains, which
		1329	might or might not bring back listener-less nodes, but don't count on it.
		1330
		1331	The fact that most connections are now optional somewhat mitigates this,
		1332	as a node can be effectively unreachable from the outside without any
		1333	problems, as long as it isn't a global node and only reaches out to other
		1334	nodes (as opposed to being contacted from other nodes).
		1335
		1336	=back
		1337
1118	=head1 SEE ALSO	1338	=head1 SEE ALSO
1119		1339
1120	L<AnyEvent::MP::Intro> - a gentle introduction.	1340	L<AnyEvent::MP::Intro> - a gentle introduction.
1121		1341
1122	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	1342	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.127 by root, Sat Mar 3 20:35:10 2012 UTC vs. Revision 1.137 by root, Wed Mar 21 23:48:39 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.127 by root, Sat Mar 3 20:35:10 2012 UTC vs.
Revision 1.137 by root, Wed Mar 21 23:48:39 2012 UTC