[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 1.142 by root, Fri Mar 23 13:44:01 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
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
52	=head1 CURRENT STATUS
53
54	bin/aemp - stable.
55	AnyEvent::MP - stable API, should work.
56	AnyEvent::MP::Intro - explains most concepts.
57	AnyEvent::MP::Kernel - mostly stable API.
58	AnyEvent::MP::Global - stable API.
59		51
60	=head1 DESCRIPTION	52	=head1 DESCRIPTION
61		53
62	This module (-family) implements a simple message passing framework.	54	This module (-family) implements a simple message passing framework.
63		55
…		…
184		176
185	use common::sense;	177	use common::sense;
186		178
187	use Carp ();	179	use Carp ();
188		180
189	use AE ();	181	use AnyEvent ();
190	use Guard ();	182	use Guard ();
191		183
192	use base "Exporter";	184	use base "Exporter";
193		185
194	our $VERSION = $AnyEvent::MP::Config::VERSION;	186	our $VERSION = $AnyEvent::MP::Config::VERSION;
…		…
197	NODE $NODE *SELF node_of after	189	NODE $NODE *SELF node_of after
198	configure	190	configure
199	snd rcv mon mon_guard kil psub peval spawn cal	191	snd rcv mon mon_guard kil psub peval spawn cal
200	port	192	port
201	db_set db_del db_reg	193	db_set db_del db_reg
		194	db_mon db_family db_keys db_values
202	);	195	);
203		196
204	our $SELF;	197	our $SELF;
205		198
206	sub _self_die() {	199	sub _self_die() {
…		…
245	=item force => $boolean (default false)	238	=item force => $boolean (default false)
246		239
247	IF true, then the values specified in the C<configure> will take	240	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	241	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.	242	the rc file to override any options specified in the program.
250
251	=item secure => $pass->($nodeid)
252
253	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	granted iff the callback returns a true value.
256
257	See F<semp setsecure> for more info.
258		243
259	=back	244	=back
260		245
261	=over 4	246	=over 4
262		247
…		…
397		382
398	=cut	383	=cut
399		384
400	sub rcv($@);	385	sub rcv($@);
401		386
402	sub _kilme {	387	my $KILME = sub {
403	die "received message on port without callback";	388	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
404	}	389	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		390	};
405		391
406	sub port(;&) {	392	sub port(;&) {
407	my $id = $UNIQ . ++$ID;	393	my $id = $UNIQ . ++$ID;
408	my $port = "$NODE#$id";	394	my $port = "$NODE#$id";
409		395
410	rcv $port, shift \|\| \&_kilme;	396	rcv $port, shift \|\| $KILME;
411		397
412	$port	398	$port
413	}	399	}
414		400
415	=item rcv $local_port, $callback->(@msg)	401	=item rcv $local_port, $callback->(@msg)
…		…
420		406
421	The global C<$SELF> (exported by this module) contains C<$port> while	407	The global C<$SELF> (exported by this module) contains C<$port> while
422	executing the callback. Runtime errors during callback execution will	408	executing the callback. Runtime errors during callback execution will
423	result in the port being C<kil>ed.	409	result in the port being C<kil>ed.
424		410
425	The default callback received all messages not matched by a more specific	411	The default callback receives all messages not matched by a more specific
426	C<tag> match.	412	C<tag> match.
427		413
428	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	414	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
429		415
430	Register (or replace) callbacks to be called on messages starting with the	416	Register (or replace) callbacks to be called on messages starting with the
…		…
594	$res	580	$res
595	}	581	}
596	}	582	}
597	}	583	}
598		584
		585	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
		586
		587	=item $guard = mon $port # kill $SELF when $port dies
		588
599	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies	589	=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
600
601	=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
602
603	=item $guard = mon $port # kill $SELF when $port dies
604		590
605	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies	591	=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
606		592
607	Monitor the given port and do something when the port is killed or	593	Monitor the given port and do something when the port is killed or
608	messages to it were lost, and optionally return a guard that can be used	594	messages to it were lost, and optionally return a guard that can be used
609	to stop monitoring again.	595	to stop monitoring again.
610		596
		597	The first two forms distinguish between "normal" and "abnormal" kil's:
		598
		599	In the first form (another port given), if the C<$port> is C<kil>'ed with
		600	a non-empty reason, the other port (C<$rcvport>) will be kil'ed with the
		601	same reason. That is, on "normal" kil's nothing happens, while under all
		602	other conditions, the other port is killed with the same reason.
		603
		604	The second form (kill self) is the same as the first form, except that
		605	C<$rvport> defaults to C<$SELF>.
		606
		607	The remaining forms don't distinguish between "normal" and "abnormal" kil's
		608	- it's up to the callback or receiver to check whether the C<@reason> is
		609	empty and act accordingly.
		610
611	In the first form (callback), the callback is simply called with any	611	In the third form (callback), the callback is simply called with any
612	number of C<@reason> elements (no @reason means that the port was deleted	612	number of C<@reason> elements (empty @reason means that the port was deleted
613	"normally"). Note also that I<< the callback B<must> never die >>, so use	613	"normally"). Note also that I<< the callback B<must> never die >>, so use
614	C<eval> if unsure.	614	C<eval> if unsure.
615		615
616	In the second form (another port given), the other port (C<$rcvport>)
617	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
618	"normal" kils nothing happens, while under all other conditions, the other
619	port is killed with the same reason.
620
621	The third form (kill self) is the same as the second form, except that
622	C<$rvport> defaults to C<$SELF>.
623
624	In the last form (message), a message of the form C<@msg, @reason> will be	616	In the last form (message), a message of the form C<$rcvport, @msg,
625	C<snd>.	617	@reason> will be C<snd>.
626		618
627	Monitoring-actions are one-shot: once messages are lost (and a monitoring	619	Monitoring-actions are one-shot: once messages are lost (and a monitoring
628	alert was raised), they are removed and will not trigger again.	620	alert was raised), they are removed and will not trigger again, even if it
		621	turns out that the port is still alive.
629		622
630	As a rule of thumb, monitoring requests should always monitor a port from	623	As a rule of thumb, monitoring requests should always monitor a remote
631	a local port (or callback). The reason is that kill messages might get	624	port locally (using a local C<$rcvport> or a callback). The reason is that
632	lost, just like any other message. Another less obvious reason is that	625	kill messages might get lost, just like any other message. Another less
633	even monitoring requests can get lost (for example, when the connection	626	obvious reason is that even monitoring requests can get lost (for example,
634	to the other node goes down permanently). When monitoring a port locally	627	when the connection to the other node goes down permanently). When
635	these problems do not exist.	628	monitoring a port locally these problems do not exist.
636		629
637	C<mon> effectively guarantees that, in the absence of hardware failures,	630	C<mon> effectively guarantees that, in the absence of hardware failures,
638	after starting the monitor, either all messages sent to the port will	631	after starting the monitor, either all messages sent to the port will
639	arrive, or the monitoring action will be invoked after possible message	632	arrive, or the monitoring action will be invoked after possible message
640	loss has been detected. No messages will be lost "in between" (after	633	loss has been detected. No messages will be lost "in between" (after
…		…
731	will be reported as reason C<< die => $@ >>.	724	will be reported as reason C<< die => $@ >>.
732		725
733	Transport/communication errors are reported as C<< transport_error =>	726	Transport/communication errors are reported as C<< transport_error =>
734	$message >>.	727	$message >>.
735		728
736	=cut	729	Common idioms:
		730
		731	# silently remove yourself, do not kill linked ports
		732	kil $SELF;
		733
		734	# report a failure in some detail
		735	kil $SELF, failure_mode_1 => "it failed with too high temperature";
		736
		737	# do not waste much time with killing, just die when something goes wrong
		738	open my $fh, "<file"
		739	or die "file: $!";
737		740
738	=item $port = spawn $node, $initfunc[, @initdata]	741	=item $port = spawn $node, $initfunc[, @initdata]
739		742
740	Creates a port on the node C<$node> (which can also be a port ID, in which	743	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).	744	case it's the node where that port resides).
…		…
833	ref $action[0]	836	ref $action[0]
834	? $action[0]()	837	? $action[0]()
835	: snd @action;	838	: snd @action;
836	};	839	};
837	}	840	}
		841
		842	#=item $cb2 = timeout $seconds, $cb[, @args]
838		843
839	=item cal $port, @msg, $callback[, $timeout]	844	=item cal $port, @msg, $callback[, $timeout]
840		845
841	A simple form of RPC - sends a message to the given C<$port> with the	846	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.	847	given contents (C<@msg>), but adds a reply port to the message.
…		…
891	=back	896	=back
892		897
893	=head1 DISTRIBUTED DATABASE	898	=head1 DISTRIBUTED DATABASE
894		899
895	AnyEvent::MP comes with a simple distributed database. The database will	900	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	901	be mirrored asynchronously on all global nodes. Other nodes bind to one
897	the global nodes for their needs.	902	of the global nodes for their needs. Every node has a "local database"
		903	which contains all the values that are set locally. All local databases
		904	are merged together to form the global database, which can be queried.
898		905
899	The database consists of a two-level hash - a hash contains a hash which	906	The database structure is that of a two-level hash - the database hash
900	contains values.	907	contains hashes which contain values, similarly to a perl hash of hashes,
		908	i.e.:
		909
		910	$DATABASE{$family}{$subkey} = $value
901		911
902	The top level hash key is called "family", and the second-level hash key	912	The top level hash key is called "family", and the second-level hash key
903	is called "subkey" or simply "key".	913	is called "subkey" or simply "key".
904		914
905	The family must be alphanumeric, i.e. start with a letter and consist	915	The family must be alphanumeric, i.e. start with a letter and consist
…		…
910	with the name of the application or module using it.	920	with the name of the application or module using it.
911		921
912	The subkeys must be non-empty strings, with no further restrictions.	922	The subkeys must be non-empty strings, with no further restrictions.
913		923
914	The values should preferably be strings, but other perl scalars should	924	The values should preferably be strings, but other perl scalars should
915	work as well (such as undef, arrays and hashes).	925	work as well (such as C<undef>, arrays and hashes).
916		926
917	Every database entry is owned by one node - adding the same family/subkey	927	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,	928	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
919	but the result might be nondeterministic, i.e. the key might have	929	but the result might be nondeterministic, i.e. the key might have
920	different values on different nodes.	930	different values on different nodes.
…		…
924	pools. For example, a worker port for image scaling might do this:	934	pools. For example, a worker port for image scaling might do this:
925		935
926	db_set my_image_scalers => $port;	936	db_set my_image_scalers => $port;
927		937
928	And clients looking for an image scaler will want to get the	938	And clients looking for an image scaler will want to get the
929	C<my_image_scalers> keys:	939	C<my_image_scalers> keys from time to time:
930		940
931	db_keys "my_image_scalers" => 60 => sub {	941	db_keys my_image_scalers => sub {
932	#d##TODO#	942	@ports = @{ $_[0] };
		943	};
		944
		945	Or better yet, they want to monitor the database family, so they always
		946	have a reasonable up-to-date copy:
		947
		948	db_mon my_image_scalers => sub {
		949	@ports = keys %{ $_[0] };
		950	};
		951
		952	In general, you can set or delete single subkeys, but query and monitor
		953	whole families only.
		954
		955	If you feel the need to monitor or query a single subkey, try giving it
		956	it's own family.
933		957
934	=over	958	=over
935		959
936	=item db_set $family => $subkey [=> $value]	960	=item $guard = db_set $family => $subkey [=> $value]
937		961
938	Sets (or replaces) a key to the database - if C<$value> is omitted,	962	Sets (or replaces) a key to the database - if C<$value> is omitted,
939	C<undef> is used instead.	963	C<undef> is used instead.
940		964
		965	When called in non-void context, C<db_set> returns a guard that
		966	automatically calls C<db_del> when it is destroyed.
		967
941	=item db_del $family => $subkey	968	=item db_del $family => $subkey...
942		969
943	Deletes a key from the database.	970	Deletes one or more subkeys from the database family.
944		971
945	=item $guard = db_reg $family => $subkey [=> $value]	972	=item $guard = db_reg $family => $port => $value
946		973
947	Sets the key on the database and returns a guard. When the guard is	974	=item $guard = db_reg $family => $port
948	destroyed, the key is deleted from the database. If C<$value> is missing,	975
949	then C<undef> is used.	976	=item $guard = db_reg $family
		977
		978	Registers a port in the given family and optionally returns a guard to
		979	remove it.
		980
		981	This function basically does the same as:
		982
		983	db_set $family => $port => $value
		984
		985	Except that the port is monitored and automatically removed from the
		986	database family when it is kil'ed.
		987
		988	If C<$value> is missing, C<undef> is used. If C<$port> is missing, then
		989	C<$SELF> is used.
		990
		991	This function is most useful to register a port in some port group (which
		992	is just another name for a database family), and have it removed when the
		993	port is gone. This works best when the port is a local port.
		994
		995	=cut
		996
		997	sub db_reg($$;$) {
		998	my $family = shift;
		999	my $port = @_ ? shift : $SELF;
		1000
		1001	my $clr = sub { db_del $family => $port };
		1002	mon $port, $clr;
		1003
		1004	db_set $family => $port => $_[0];
		1005
		1006	defined wantarray
		1007	and &Guard::guard ($clr)
		1008	}
		1009
		1010	=item db_family $family => $cb->(\%familyhash)
		1011
		1012	Queries the named database C<$family> and call the callback with the
		1013	family represented as a hash. You can keep and freely modify the hash.
		1014
		1015	=item db_keys $family => $cb->(\@keys)
		1016
		1017	Same as C<db_family>, except it only queries the family I<subkeys> and passes
		1018	them as array reference to the callback.
		1019
		1020	=item db_values $family => $cb->(\@values)
		1021
		1022	Same as C<db_family>, except it only queries the family I<values> and passes them
		1023	as array reference to the callback.
		1024
		1025	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)
		1026
		1027	Creates a monitor on the given database family. Each time a key is set
		1028	or or is deleted the callback is called with a hash containing the
		1029	database family and three lists of added, changed and deleted subkeys,
		1030	respectively. If no keys have changed then the array reference might be
		1031	C<undef> or even missing.
		1032
		1033	If not called in void context, a guard object is returned that, when
		1034	destroyed, stops the monitor.
		1035
		1036	The family hash reference and the key arrays belong to AnyEvent::MP and
		1037	B<must not be modified or stored> by the callback. When in doubt, make a
		1038	copy.
		1039
		1040	As soon as possible after the monitoring starts, the callback will be
		1041	called with the intiial contents of the family, even if it is empty,
		1042	i.e. there will always be a timely call to the callback with the current
		1043	contents.
		1044
		1045	It is possible that the callback is called with a change event even though
		1046	the subkey is already present and the value has not changed.
		1047
		1048	The monitoring stops when the guard object is destroyed.
		1049
		1050	Example: on every change to the family "mygroup", print out all keys.
		1051
		1052	my $guard = db_mon mygroup => sub {
		1053	my ($family, $a, $c, $d) = @_;
		1054	print "mygroup members: ", (join " ", keys %$family), "\n";
		1055	};
		1056
		1057	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1058
		1059	my $guard; $guard = db_mon My::Module::workers => sub {
		1060	my ($family, $a, $c, $d) = @_;
		1061	return unless %$family;
		1062	undef $guard;
		1063	print "My::Module::workers now nonempty\n";
		1064	};
		1065
		1066	Example: print all changes to the family "AnyRvent::Fantasy::Module".
		1067
		1068	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
		1069	my ($family, $a, $c, $d) = @_;
		1070
		1071	print "+$_=$family->{$_}\n" for @$a;
		1072	print "*$_=$family->{$_}\n" for @$c;
		1073	print "-$_=$family->{$_}\n" for @$d;
		1074	};
950		1075
951	=cut	1076	=cut
952		1077
953	=back	1078	=back
954		1079
…		…
1113	Keeping your messages simple, concentrating on data structures rather than	1238	Keeping your messages simple, concentrating on data structures rather than
1114	objects, will keep your messages clean, tidy and efficient.	1239	objects, will keep your messages clean, tidy and efficient.
1115		1240
1116	=back	1241	=back
1117		1242
		1243	=head1 PORTING FROM AnyEvent::MP VERSION 1.X
		1244
		1245	AEMP version 2 has a few major incompatible changes compared to version 1:
		1246
		1247	=over 4
		1248
		1249	=item AnyEvent::MP::Global no longer has group management functions.
		1250
		1251	At least not officially - the grp_* functions are still exported and might
		1252	work, but they will be removed in some later release.
		1253
		1254	AnyEvent::MP now comes with a distributed database that is more
		1255	powerful. Its database families map closely to port groups, but the API
		1256	has changed (the functions are also now exported by AnyEvent::MP). Here is
		1257	a rough porting guide:
		1258
		1259	grp_reg $group, $port # old
		1260	db_reg $group, $port # new
		1261
		1262	$list = grp_get $group # old
		1263	db_keys $group, sub { my $list = shift } # new
		1264
		1265	grp_mon $group, $cb->(\@ports, $add, $del) # old
		1266	db_mon $group, $cb->(\%ports, $add, $change, $del) # new
		1267
		1268	C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> is
		1269	no longer instant, because the local node might not have a copy of the
		1270	group. You can either modify your code to allow for a callback, or use
		1271	C<db_mon> to keep an updated copy of the group:
		1272
		1273	my $local_group_copy;
		1274	db_mon $group => sub { $local_group_copy = $_[0] };
		1275
		1276	# now "keys %$local_group_copy" always returns the most up-to-date
		1277	# list of ports in the group.
		1278
		1279	C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon>
		1280	passes a hash as first argument, and an extra C<$chg> argument that can be
		1281	ignored:
		1282
		1283	db_mon $group => sub {
		1284	my ($ports, $add, $chg, $lde) = @_;
		1285	$ports = [keys %$ports];
		1286
		1287	# now $ports, $add and $del are the same as
		1288	# were originally passed by grp_mon.
		1289	...
		1290	};
		1291
		1292	=item Nodes not longer connect to all other nodes.
		1293
		1294	In AEMP 1.x, every node automatically loads the L<AnyEvent::MP::Global>
		1295	module, which in turn would create connections to all other nodes in the
		1296	network (helped by the seed nodes).
		1297
		1298	In version 2.x, global nodes still connect to all other global nodes, but
		1299	other nodes don't - now every node either is a global node itself, or
		1300	attaches itself to another global node.
		1301
		1302	If a node isn't a global node itself, then it attaches itself to one
		1303	of its seed nodes. If that seed node isn't a global node yet, it will
		1304	automatically be upgraded to a global node.
		1305
		1306	So in many cases, nothing needs to be changed - one just has to make sure
		1307	that all seed nodes are meshed together with the other seed nodes (as with
		1308	AEMP 1.x), and other nodes specify them as seed nodes. This is most easily
		1309	achieved by specifying the same set of seed nodes for all nodes in the
		1310	network.
		1311
		1312	Not opening a connection to every other node is usually an advantage,
		1313	except when you need the lower latency of an already established
		1314	connection. To ensure a node establishes a connection to another node,
		1315	you can monitor the node port (C<mon $node, ...>), which will attempt to
		1316	create the connection (and notify you when the connection fails).
		1317
		1318	=item Listener-less nodes (nodes without binds) are gone.
		1319
		1320	And are not coming back, at least not in their old form. If no C<binds>
		1321	are specified for a node, AnyEvent::MP assumes a default of C<:>.
		1322
		1323	There are vague plans to implement some form of routing domains, which
		1324	might or might not bring back listener-less nodes, but don't count on it.
		1325
		1326	The fact that most connections are now optional somewhat mitigates this,
		1327	as a node can be effectively unreachable from the outside without any
		1328	problems, as long as it isn't a global node and only reaches out to other
		1329	nodes (as opposed to being contacted from other nodes).
		1330
		1331	=item $AnyEvent::MP::Kernel::WARN has gone.
		1332
		1333	AnyEvent has acquired a logging framework (L<AnyEvent::Log>), and AEMP now
		1334	uses this, and so should your programs.
		1335
		1336	Every module now documents what kinds of messages it generates, with
		1337	AnyEvent::MP acting as a catch all.
		1338
		1339	On the positive side, this means that instead of setting
		1340	C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE> -
		1341	much less to type.
		1342
		1343	=back
		1344
		1345	=head1 LOGGING
		1346
		1347	AnyEvent::MP does not normally log anything by itself, but sinc eit is the
		1348	root of the contetx hierarchy for AnyEvent::MP modules, it will receive
		1349	all log messages by submodules.
		1350
1118	=head1 SEE ALSO	1351	=head1 SEE ALSO
1119		1352
1120	L<AnyEvent::MP::Intro> - a gentle introduction.	1353	L<AnyEvent::MP::Intro> - a gentle introduction.
1121		1354
1122	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 1.127 by root, Sat Mar 3 20:35:10 2012 UTC vs. Revision 1.142 by root, Fri Mar 23 13:44:01 2012 UTC

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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 1.142 by root, Fri Mar 23 13:44:01 2012 UTC