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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.129 by root, Thu Mar 8 21:37:51 2012 UTC vs.
Revision 1.138 by root, Thu Mar 22 00:48:29 2012 UTC

…		…
247		247
248	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
249	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
250	the rc file to override any options specified in the program.	250	the rc file to override any options specified in the program.
251		251
252	=item secure => $pass->($nodeid)	252	=item secure => $pass->(@msg)
253		253
254	In addition to specifying a boolean, you can specify a code reference that	254	In addition to specifying a boolean, you can specify a code reference that
255	is called for every remote execution attempt - the execution request is	255	is called for every code execution attempt - the execution request is
256	granted iff the callback returns a true value.	256	granted iff the callback returns a true value.
		257
		258	Most of the time the callback should look only at
		259	C<$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).
257		262
258	See F<semp setsecure> for more info.	263	See F<semp setsecure> for more info.
259		264
260	=back	265	=back
261		266
…		…
398		403
399	=cut	404	=cut
400		405
401	sub rcv($@);	406	sub rcv($@);
402		407
403	sub _kilme {	408	my $KILME = sub {
404	die "received message on port without callback";	409	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
405	}	410	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		411	};
406		412
407	sub port(;&) {	413	sub port(;&) {
408	my $id = $UNIQ . ++$ID;	414	my $id = $UNIQ . ++$ID;
409	my $port = "$NODE#$id";	415	my $port = "$NODE#$id";
410		416
411	rcv $port, shift \|\| \&_kilme;	417	rcv $port, shift \|\| $KILME;
412		418
413	$port	419	$port
414	}	420	}
415		421
416	=item rcv $local_port, $callback->(@msg)	422	=item rcv $local_port, $callback->(@msg)
…		…
421		427
422	The global C<$SELF> (exported by this module) contains C<$port> while	428	The global C<$SELF> (exported by this module) contains C<$port> while
423	executing the callback. Runtime errors during callback execution will	429	executing the callback. Runtime errors during callback execution will
424	result in the port being C<kil>ed.	430	result in the port being C<kil>ed.
425		431
426	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
427	C<tag> match.	433	C<tag> match.
428		434
429	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	435	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
430		436
431	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
…		…
732	will be reported as reason C<< die => $@ >>.	738	will be reported as reason C<< die => $@ >>.
733		739
734	Transport/communication errors are reported as C<< transport_error =>	740	Transport/communication errors are reported as C<< transport_error =>
735	$message >>.	741	$message >>.
736		742
737	=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: $!";
738		754
739	=item $port = spawn $node, $initfunc[, @initdata]	755	=item $port = spawn $node, $initfunc[, @initdata]
740		756
741	Creates a port on the node C<$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
742	case it's the node where that port resides).	758	case it's the node where that port resides).
…		…
894	=back	910	=back
895		911
896	=head1 DISTRIBUTED DATABASE	912	=head1 DISTRIBUTED DATABASE
897		913
898	AnyEvent::MP comes with a simple distributed database. The database will	914	AnyEvent::MP comes with a simple distributed database. The database will
899	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
900	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.
901		919
902	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
903	contains values.	921	contains hashes which contain values, similarly to a perl hash of hashes,
		922	i.e.:
		923
		924	$DATABASE{$family}{$subkey} = $value
904		925
905	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
906	is called "subkey" or simply "key".	927	is called "subkey" or simply "key".
907		928
908	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
…		…
913	with the name of the application or module using it.	934	with the name of the application or module using it.
914		935
915	The subkeys must be non-empty strings, with no further restrictions.	936	The subkeys must be non-empty strings, with no further restrictions.
916		937
917	The values should preferably be strings, but other perl scalars should	938	The values should preferably be strings, but other perl scalars should
918	work as well (such as undef, arrays and hashes).	939	work as well (such as C<undef>, arrays and hashes).
919		940
920	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
921	combination on multiple nodes will not cause discomfort for AnyEvent::MP,	942	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
922	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
923	different values on different nodes.	944	different values on different nodes.
…		…
948	If you feel the need to monitor or query a single subkey, try giving it	969	If you feel the need to monitor or query a single subkey, try giving it
949	it's own family.	970	it's own family.
950		971
951	=over	972	=over
952		973
953	=item db_set $family => $subkey [=> $value]	974	=item $guard = db_set $family => $subkey [=> $value]
954		975
955	Sets (or replaces) a key to the database - if C<$value> is omitted,	976	Sets (or replaces) a key to the database - if C<$value> is omitted,
956	C<undef> is used instead.	977	C<undef> is used instead.
957		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
958	=item db_del $family => $subkey	982	=item db_del $family => $subkey...
959		983
960	Deletes a key from the database.	984	Deletes one or more subkeys from the database family.
961		985
962	=item $guard = db_reg $family => $subkey [=> $value]	986	=item $guard = db_reg $family => $port => $value
963		987
964	Sets the key on the database and returns a guard. When the guard is	988	=item $guard = db_reg $family => $port
965	destroyed, the key is deleted from the database. If C<$value> is missing,	989
966	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	}
967		1023
968	=item db_family $family => $cb->(\%familyhash)	1024	=item db_family $family => $cb->(\%familyhash)
969		1025
970	Queries the named database C<$family> and call the callback with the	1026	Queries the named database C<$family> and call the callback with the
971	family represented as a hash. You can keep and freely modify the hash.	1027	family represented as a hash. You can keep and freely modify the hash.
…		…
978	=item db_values $family => $cb->(\@values)	1034	=item db_values $family => $cb->(\@values)
979		1035
980	Same as C<db_family>, except it only queries the family I<values> and passes them	1036	Same as C<db_family>, except it only queries the family I<values> and passes them
981	as array reference to the callback.	1037	as array reference to the callback.
982		1038
983	=item $guard = db_mon $family => $cb->($familyhash, \@subkeys...)	1039	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)
984		1040
985	Creates a monitor on the given database family. Each time a key is set or	1041	Creates a monitor on the given database family. Each time a key is set
986	or is deleted the callback is called with a hash containing the database	1042	or or is deleted the callback is called with a hash containing the
987	family and an arrayref with subkeys that have changed.	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.
988		1046
989	Specifically, if one of the passed subkeys exists in the $familyhash, then	1047	If not called in void context, a guard object is returned that, when
990	it is currently set to the value in the $familyhash. Otherwise, it has	1048	destroyed, stops the monitor.
991	been deleted.
992		1049
993	The family hash reference belongs to AnyEvent::MP and B<must not be	1050	The family hash reference and the key arrays belong to AnyEvent::MP and
994	modified or stored> by the callback. When in doubt, make a copy.	1051	B<must not be modified or stored> by the callback. When in doubt, make a
		1052	copy.
995		1053
996	The first call will be with the current contents of the family and all	1054	As soon as possible after the monitoring starts, the callback will be
997	keys, as if they were just added.	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.
998		1058
999	It is possible that the callback is called with a change event even though	1059	It is possible that the callback is called with a change event even though
1000	the subkey is already present and the value has not changed.	1060	the subkey is already present and the value has not changed.
1001		1061
1002	The monitoring stops when the guard object is destroyed.	1062	The monitoring stops when the guard object is destroyed.
1003		1063
1004	Example: on every change to the family "mygroup", print out all keys.	1064	Example: on every change to the family "mygroup", print out all keys.
1005		1065
1006	my $guard = db_mon mygroup => sub {	1066	my $guard = db_mon mygroup => sub {
1007	my ($family, $keys) = @_;	1067	my ($family, $a, $c, $d) = @_;
1008	print "mygroup members: ", (join " ", keys %$family), "\n";	1068	print "mygroup members: ", (join " ", keys %$family), "\n";
1009	};	1069	};
1010		1070
1011	Exmaple: wait until the family "My::Module::workers" is non-empty.	1071	Exmaple: wait until the family "My::Module::workers" is non-empty.
1012		1072
1013	my $guard; $guard = db_mon My::Module::workers => sub {	1073	my $guard; $guard = db_mon My::Module::workers => sub {
1014	my ($family, $keys) = @_;	1074	my ($family, $a, $c, $d) = @_;
1015	return unless %$family;	1075	return unless %$family;
1016	undef $guard;	1076	undef $guard;
1017	print "My::Module::workers now nonempty\n";	1077	print "My::Module::workers now nonempty\n";
1018	};	1078	};
1019		1079
1020	Example: print all changes to the family "AnyRvent::Fantasy::Module".	1080	Example: print all changes to the family "AnyRvent::Fantasy::Module".
1021		1081
1022	my $guard = db_mon AnyRvent::Fantasy::Module => sub {	1082	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
1023	my ($family, $keys) = @_;	1083	my ($family, $a, $c, $d) = @_;
1024		1084
1025	for (@$keys) {	1085	print "+$_=$family->{$_}\n" for @$a;
1026	print "$_: ",	1086	print "*$_=$family->{$_}\n" for @$c;
1027	(exists $family->{$_}	1087	print "-$_=$family->{$_}\n" for @$d;
1028	? $family->{$_}
1029	: "(deleted)"),
1030	"\n";
1031	}
1032	};	1088	};
1033		1089
1034	=cut	1090	=cut
1035		1091
1036	=back	1092	=back
…		…
1196	Keeping your messages simple, concentrating on data structures rather than	1252	Keeping your messages simple, concentrating on data structures rather than
1197	objects, will keep your messages clean, tidy and efficient.	1253	objects, will keep your messages clean, tidy and efficient.
1198		1254
1199	=back	1255	=back
1200		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 (nodes without binds) are gone.
		1325
		1326	And are not coming back, at least not in their old form. If no C<binds>
		1327	are specified for a node, AnyEvent::MP now assumes a default of C<:>.
		1328
		1329	There are vague plans to implement some form of routing domains, which
		1330	might or might not bring back listener-less nodes, but don't count on it.
		1331
		1332	The fact that most connections are now optional somewhat mitigates this,
		1333	as a node can be effectively unreachable from the outside without any
		1334	problems, as long as it isn't a global node and only reaches out to other
		1335	nodes (as opposed to being contacted from other nodes).
		1336
		1337	=item $AnyEvent::MP::Kernel::WARN has gone.
		1338
		1339	AnyEvent has acquired a logging framework (L<AnyEvent::Log>), and AEMP now
		1340	uses this, and so should your programs.
		1341
		1342	Every module now documents what kinds of messages it generates, with
		1343	AnyEvent::MP acting as a catch all.
		1344
		1345	On the positive side, this means that instead of setting
		1346	C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE>,
		1347	much less to type.
		1348
		1349	=back
		1350
1201	=head1 SEE ALSO	1351	=head1 SEE ALSO
1202		1352
1203	L<AnyEvent::MP::Intro> - a gentle introduction.	1353	L<AnyEvent::MP::Intro> - a gentle introduction.
1204		1354
1205	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	1355	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.129 by root, Thu Mar 8 21:37:51 2012 UTC vs. Revision 1.138 by root, Thu Mar 22 00:48:29 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.129 by root, Thu Mar 8 21:37:51 2012 UTC vs.
Revision 1.138 by root, Thu Mar 22 00:48:29 2012 UTC