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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.130 by root, Fri Mar 9 17:05:26 2012 UTC vs.
Revision 1.143 by root, Fri Mar 23 17:54:36 2012 UTC

…		…
47	# execute callbacks in $SELF port context	47	# execute callbacks in $SELF port context
48	my $timer = AE::timer 1, 0, psub {	48	my $timer = AE::timer 1, 0, psub {
49	die "kill the port, delayed";	49	die "kill the port, delayed";
50	};	50	};
51		51
52	=head1 CURRENT STATUS	52	# distributed database - modification
		53	db_set $family => $subkey [=> $value] # add a subkey
		54	db_del $family => $subkey... # delete one or more subkeys
		55	db_reg $family => $port [=> $value] # register a port
53		56
54	bin/aemp - stable.	57	# distributed database - queries
55	AnyEvent::MP - stable API, should work.	58	db_family $family => $cb->(\%familyhash)
56	AnyEvent::MP::Intro - explains most concepts.	59	db_keys $family => $cb->(\@keys)
57	AnyEvent::MP::Kernel - mostly stable API.	60	db_values $family => $cb->(\@values)
58	AnyEvent::MP::Global - stable API.	61
		62	# distributed database - monitoring a family
		63	db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
59		64
60	=head1 DESCRIPTION	65	=head1 DESCRIPTION
61		66
62	This module (-family) implements a simple message passing framework.	67	This module (-family) implements a simple message passing framework.
63		68
…		…
184		189
185	use common::sense;	190	use common::sense;
186		191
187	use Carp ();	192	use Carp ();
188		193
189	use AE ();	194	use AnyEvent ();
190	use Guard ();	195	use Guard ();
191		196
192	use base "Exporter";	197	use base "Exporter";
193		198
194	our $VERSION = $AnyEvent::MP::Config::VERSION;	199	our $VERSION = $AnyEvent::MP::Config::VERSION;
…		…
247		252
248	IF true, then the values specified in the C<configure> will take	253	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	254	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.	255	the rc file to override any options specified in the program.
251		256
252	=item secure => $pass->($nodeid)
253
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
256	granted iff the callback returns a true value.
257
258	See F<semp setsecure> for more info.
259
260	=back	257	=back
261		258
262	=over 4	259	=over 4
263		260
264	=item step 1, gathering configuration from profiles	261	=item step 1, gathering configuration from profiles
…		…
398		395
399	=cut	396	=cut
400		397
401	sub rcv($@);	398	sub rcv($@);
402		399
403	sub _kilme {	400	my $KILME = sub {
404	die "received message on port without callback";	401	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
405	}	402	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		403	};
406		404
407	sub port(;&) {	405	sub port(;&) {
408	my $id = $UNIQ . ++$ID;	406	my $id = $UNIQ . ++$ID;
409	my $port = "$NODE#$id";	407	my $port = "$NODE#$id";
410		408
411	rcv $port, shift \|\| \&_kilme;	409	rcv $port, shift \|\| $KILME;
412		410
413	$port	411	$port
414	}	412	}
415		413
416	=item rcv $local_port, $callback->(@msg)	414	=item rcv $local_port, $callback->(@msg)
…		…
421		419
422	The global C<$SELF> (exported by this module) contains C<$port> while	420	The global C<$SELF> (exported by this module) contains C<$port> while
423	executing the callback. Runtime errors during callback execution will	421	executing the callback. Runtime errors during callback execution will
424	result in the port being C<kil>ed.	422	result in the port being C<kil>ed.
425		423
426	The default callback received all messages not matched by a more specific	424	The default callback receives all messages not matched by a more specific
427	C<tag> match.	425	C<tag> match.
428		426
429	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	427	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
430		428
431	Register (or replace) callbacks to be called on messages starting with the	429	Register (or replace) callbacks to be called on messages starting with the
…		…
595	$res	593	$res
596	}	594	}
597	}	595	}
598	}	596	}
599		597
		598	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
		599
		600	=item $guard = mon $port # kill $SELF when $port dies
		601
600	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies	602	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
601
602	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
603
604	=item $guard = mon $port # kill $SELF when $port dies
605		603
606	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies	604	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
607		605
608	Monitor the given port and do something when the port is killed or	606	Monitor the given port and do something when the port is killed or
609	messages to it were lost, and optionally return a guard that can be used	607	messages to it were lost, and optionally return a guard that can be used
610	to stop monitoring again.	608	to stop monitoring again.
611		609
		610	The first two forms distinguish between "normal" and "abnormal" kil's:
		611
		612	In the first form (another port given), if the C<$port> is C<kil>'ed with
		613	a non-empty reason, the other port (C<$rcvport>) will be kil'ed with the
		614	same reason. That is, on "normal" kil's nothing happens, while under all
		615	other conditions, the other port is killed with the same reason.
		616
		617	The second form (kill self) is the same as the first form, except that
		618	C<$rvport> defaults to C<$SELF>.
		619
		620	The remaining forms don't distinguish between "normal" and "abnormal" kil's
		621	- it's up to the callback or receiver to check whether the C<@reason> is
		622	empty and act accordingly.
		623
612	In the first form (callback), the callback is simply called with any	624	In the third form (callback), the callback is simply called with any
613	number of C<@reason> elements (no @reason means that the port was deleted	625	number of C<@reason> elements (empty @reason means that the port was deleted
614	"normally"). Note also that I<< the callback B<must> never die >>, so use	626	"normally"). Note also that I<< the callback B<must> never die >>, so use
615	C<eval> if unsure.	627	C<eval> if unsure.
616		628
617	In the second form (another port given), the other port (C<$rcvport>)
618	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
619	"normal" kils nothing happens, while under all other conditions, the other
620	port is killed with the same reason.
621
622	The third form (kill self) is the same as the second form, except that
623	C<$rvport> defaults to C<$SELF>.
624
625	In the last form (message), a message of the form C<@msg, @reason> will be	629	In the last form (message), a message of the form C<$rcvport, @msg,
626	C<snd>.	630	@reason> will be C<snd>.
627		631
628	Monitoring-actions are one-shot: once messages are lost (and a monitoring	632	Monitoring-actions are one-shot: once messages are lost (and a monitoring
629	alert was raised), they are removed and will not trigger again.	633	alert was raised), they are removed and will not trigger again, even if it
		634	turns out that the port is still alive.
630		635
631	As a rule of thumb, monitoring requests should always monitor a port from	636	As a rule of thumb, monitoring requests should always monitor a remote
632	a local port (or callback). The reason is that kill messages might get	637	port locally (using a local C<$rcvport> or a callback). The reason is that
633	lost, just like any other message. Another less obvious reason is that	638	kill messages might get lost, just like any other message. Another less
634	even monitoring requests can get lost (for example, when the connection	639	obvious reason is that even monitoring requests can get lost (for example,
635	to the other node goes down permanently). When monitoring a port locally	640	when the connection to the other node goes down permanently). When
636	these problems do not exist.	641	monitoring a port locally these problems do not exist.
637		642
638	C<mon> effectively guarantees that, in the absence of hardware failures,	643	C<mon> effectively guarantees that, in the absence of hardware failures,
639	after starting the monitor, either all messages sent to the port will	644	after starting the monitor, either all messages sent to the port will
640	arrive, or the monitoring action will be invoked after possible message	645	arrive, or the monitoring action will be invoked after possible message
641	loss has been detected. No messages will be lost "in between" (after	646	loss has been detected. No messages will be lost "in between" (after
…		…
732	will be reported as reason C<< die => $@ >>.	737	will be reported as reason C<< die => $@ >>.
733		738
734	Transport/communication errors are reported as C<< transport_error =>	739	Transport/communication errors are reported as C<< transport_error =>
735	$message >>.	740	$message >>.
736		741
737	=cut	742	Common idioms:
		743
		744	# silently remove yourself, do not kill linked ports
		745	kil $SELF;
		746
		747	# report a failure in some detail
		748	kil $SELF, failure_mode_1 => "it failed with too high temperature";
		749
		750	# do not waste much time with killing, just die when something goes wrong
		751	open my $fh, "<file"
		752	or die "file: $!";
738		753
739	=item $port = spawn $node, $initfunc[, @initdata]	754	=item $port = spawn $node, $initfunc[, @initdata]
740		755
741	Creates a port on the node C<$node> (which can also be a port ID, in which	756	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).	757	case it's the node where that port resides).
…		…
894	=back	909	=back
895		910
896	=head1 DISTRIBUTED DATABASE	911	=head1 DISTRIBUTED DATABASE
897		912
898	AnyEvent::MP comes with a simple distributed database. The database will	913	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	914	be mirrored asynchronously on all global nodes. Other nodes bind to one
900	the global nodes for their needs.	915	of the global nodes for their needs. Every node has a "local database"
		916	which contains all the values that are set locally. All local databases
		917	are merged together to form the global database, which can be queried.
901		918
902	The database consists of a two-level hash - a hash contains a hash which	919	The database structure is that of a two-level hash - the database hash
903	contains values.	920	contains hashes which contain values, similarly to a perl hash of hashes,
		921	i.e.:
		922
		923	$DATABASE{$family}{$subkey} = $value
904		924
905	The top level hash key is called "family", and the second-level hash key	925	The top level hash key is called "family", and the second-level hash key
906	is called "subkey" or simply "key".	926	is called "subkey" or simply "key".
907		927
908	The family must be alphanumeric, i.e. start with a letter and consist	928	The family must be alphanumeric, i.e. start with a letter and consist
…		…
913	with the name of the application or module using it.	933	with the name of the application or module using it.
914		934
915	The subkeys must be non-empty strings, with no further restrictions.	935	The subkeys must be non-empty strings, with no further restrictions.
916		936
917	The values should preferably be strings, but other perl scalars should	937	The values should preferably be strings, but other perl scalars should
918	work as well (such as undef, arrays and hashes).	938	work as well (such as C<undef>, arrays and hashes).
919		939
920	Every database entry is owned by one node - adding the same family/subkey	940	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,	941	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
922	but the result might be nondeterministic, i.e. the key might have	942	but the result might be nondeterministic, i.e. the key might have
923	different values on different nodes.	943	different values on different nodes.
…		…
948	If you feel the need to monitor or query a single subkey, try giving it	968	If you feel the need to monitor or query a single subkey, try giving it
949	it's own family.	969	it's own family.
950		970
951	=over	971	=over
952		972
953	=item db_set $family => $subkey [=> $value]	973	=item $guard = db_set $family => $subkey [=> $value]
954		974
955	Sets (or replaces) a key to the database - if C<$value> is omitted,	975	Sets (or replaces) a key to the database - if C<$value> is omitted,
956	C<undef> is used instead.	976	C<undef> is used instead.
957		977
		978	When called in non-void context, C<db_set> returns a guard that
		979	automatically calls C<db_del> when it is destroyed.
		980
958	=item db_del $family => $subkey...	981	=item db_del $family => $subkey...
959		982
960	Deletes one or more subkeys from the database family.	983	Deletes one or more subkeys from the database family.
961		984
962	=item $guard = db_reg $family => $subkey [=> $value]	985	=item $guard = db_reg $family => $port => $value
963		986
964	Sets the key on the database and returns a guard. When the guard is	987	=item $guard = db_reg $family => $port
965	destroyed, the key is deleted from the database. If C<$value> is missing,	988
966	then C<undef> is used.	989	=item $guard = db_reg $family
		990
		991	Registers a port in the given family and optionally returns a guard to
		992	remove it.
		993
		994	This function basically does the same as:
		995
		996	db_set $family => $port => $value
		997
		998	Except that the port is monitored and automatically removed from the
		999	database family when it is kil'ed.
		1000
		1001	If C<$value> is missing, C<undef> is used. If C<$port> is missing, then
		1002	C<$SELF> is used.
		1003
		1004	This function is most useful to register a port in some port group (which
		1005	is just another name for a database family), and have it removed when the
		1006	port is gone. This works best when the port is a local port.
		1007
		1008	=cut
		1009
		1010	sub db_reg($$;$) {
		1011	my $family = shift;
		1012	my $port = @_ ? shift : $SELF;
		1013
		1014	my $clr = sub { db_del $family => $port };
		1015	mon $port, $clr;
		1016
		1017	db_set $family => $port => $_[0];
		1018
		1019	defined wantarray
		1020	and &Guard::guard ($clr)
		1021	}
967		1022
968	=item db_family $family => $cb->(\%familyhash)	1023	=item db_family $family => $cb->(\%familyhash)
969		1024
970	Queries the named database C<$family> and call the callback with the	1025	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.	1026	family represented as a hash. You can keep and freely modify the hash.
…		…
978	=item db_values $family => $cb->(\@values)	1033	=item db_values $family => $cb->(\@values)
979		1034
980	Same as C<db_family>, except it only queries the family I<values> and passes them	1035	Same as C<db_family>, except it only queries the family I<values> and passes them
981	as array reference to the callback.	1036	as array reference to the callback.
982		1037
983	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)	1038	=item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
984		1039
985	Creates a monitor on the given database family. Each time a key is set	1040	Creates a monitor on the given database family. Each time a key is set
986	or or is deleted the callback is called with a hash containing the	1041	or or is deleted the callback is called with a hash containing the
987	database family and three lists of added, changed and deleted subkeys,	1042	database family and three lists of added, changed and deleted subkeys,
988	respectively. If no keys have changed then the array reference might be	1043	respectively. If no keys have changed then the array reference might be
989	C<undef> or even missing.	1044	C<undef> or even missing.
		1045
		1046	If not called in void context, a guard object is returned that, when
		1047	destroyed, stops the monitor.
990		1048
991	The family hash reference and the key arrays belong to AnyEvent::MP and	1049	The family hash reference and the key arrays belong to AnyEvent::MP and
992	B<must not be modified or stored> by the callback. When in doubt, make a	1050	B<must not be modified or stored> by the callback. When in doubt, make a
993	copy.	1051	copy.
994		1052
…		…
1193	Keeping your messages simple, concentrating on data structures rather than	1251	Keeping your messages simple, concentrating on data structures rather than
1194	objects, will keep your messages clean, tidy and efficient.	1252	objects, will keep your messages clean, tidy and efficient.
1195		1253
1196	=back	1254	=back
1197		1255
		1256	=head1 PORTING FROM AnyEvent::MP VERSION 1.X
		1257
		1258	AEMP version 2 has a few major incompatible changes compared to version 1:
		1259
		1260	=over 4
		1261
		1262	=item AnyEvent::MP::Global no longer has group management functions.
		1263
		1264	At least not officially - the grp_* functions are still exported and might
		1265	work, but they will be removed in some later release.
		1266
		1267	AnyEvent::MP now comes with a distributed database that is more
		1268	powerful. Its database families map closely to port groups, but the API
		1269	has changed (the functions are also now exported by AnyEvent::MP). Here is
		1270	a rough porting guide:
		1271
		1272	grp_reg $group, $port # old
		1273	db_reg $group, $port # new
		1274
		1275	$list = grp_get $group # old
		1276	db_keys $group, sub { my $list = shift } # new
		1277
		1278	grp_mon $group, $cb->(\@ports, $add, $del) # old
		1279	db_mon $group, $cb->(\%ports, $add, $change, $del) # new
		1280
		1281	C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> is
		1282	no longer instant, because the local node might not have a copy of the
		1283	group. You can either modify your code to allow for a callback, or use
		1284	C<db_mon> to keep an updated copy of the group:
		1285
		1286	my $local_group_copy;
		1287	db_mon $group => sub { $local_group_copy = $_[0] };
		1288
		1289	# now "keys %$local_group_copy" always returns the most up-to-date
		1290	# list of ports in the group.
		1291
		1292	C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon>
		1293	passes a hash as first argument, and an extra C<$chg> argument that can be
		1294	ignored:
		1295
		1296	db_mon $group => sub {
		1297	my ($ports, $add, $chg, $lde) = @_;
		1298	$ports = [keys %$ports];
		1299
		1300	# now $ports, $add and $del are the same as
		1301	# were originally passed by grp_mon.
		1302	...
		1303	};
		1304
		1305	=item Nodes not longer connect to all other nodes.
		1306
		1307	In AEMP 1.x, every node automatically loads the L<AnyEvent::MP::Global>
		1308	module, which in turn would create connections to all other nodes in the
		1309	network (helped by the seed nodes).
		1310
		1311	In version 2.x, global nodes still connect to all other global nodes, but
		1312	other nodes don't - now every node either is a global node itself, or
		1313	attaches itself to another global node.
		1314
		1315	If a node isn't a global node itself, then it attaches itself to one
		1316	of its seed nodes. If that seed node isn't a global node yet, it will
		1317	automatically be upgraded to a global node.
		1318
		1319	So in many cases, nothing needs to be changed - one just has to make sure
		1320	that all seed nodes are meshed together with the other seed nodes (as with
		1321	AEMP 1.x), and other nodes specify them as seed nodes. This is most easily
		1322	achieved by specifying the same set of seed nodes for all nodes in the
		1323	network.
		1324
		1325	Not opening a connection to every other node is usually an advantage,
		1326	except when you need the lower latency of an already established
		1327	connection. To ensure a node establishes a connection to another node,
		1328	you can monitor the node port (C<mon $node, ...>), which will attempt to
		1329	create the connection (and notify you when the connection fails).
		1330
		1331	=item Listener-less nodes (nodes without binds) are gone.
		1332
		1333	And are not coming back, at least not in their old form. If no C<binds>
		1334	are specified for a node, AnyEvent::MP assumes a default of C<:>.
		1335
		1336	There are vague plans to implement some form of routing domains, which
		1337	might or might not bring back listener-less nodes, but don't count on it.
		1338
		1339	The fact that most connections are now optional somewhat mitigates this,
		1340	as a node can be effectively unreachable from the outside without any
		1341	problems, as long as it isn't a global node and only reaches out to other
		1342	nodes (as opposed to being contacted from other nodes).
		1343
		1344	=item $AnyEvent::MP::Kernel::WARN has gone.
		1345
		1346	AnyEvent has acquired a logging framework (L<AnyEvent::Log>), and AEMP now
		1347	uses this, and so should your programs.
		1348
		1349	Every module now documents what kinds of messages it generates, with
		1350	AnyEvent::MP acting as a catch all.
		1351
		1352	On the positive side, this means that instead of setting
		1353	C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE> -
		1354	much less to type.
		1355
		1356	=back
		1357
		1358	=head1 LOGGING
		1359
		1360	AnyEvent::MP does not normally log anything by itself, but sinc eit is the
		1361	root of the contetx hierarchy for AnyEvent::MP modules, it will receive
		1362	all log messages by submodules.
		1363
1198	=head1 SEE ALSO	1364	=head1 SEE ALSO
1199		1365
1200	L<AnyEvent::MP::Intro> - a gentle introduction.	1366	L<AnyEvent::MP::Intro> - a gentle introduction.
1201		1367
1202	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	1368	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.130 by root, Fri Mar 9 17:05:26 2012 UTC vs. Revision 1.143 by root, Fri Mar 23 17:54:36 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.130 by root, Fri Mar 9 17:05:26 2012 UTC vs.
Revision 1.143 by root, Fri Mar 23 17:54:36 2012 UTC