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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.121 by root, Tue Feb 28 18:37:24 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
…		…
82		82
83	Ports are represented by (printable) strings called "port IDs".	83	Ports are represented by (printable) strings called "port IDs".
84		84
85	=item port ID - C<nodeid#portname>	85	=item port ID - C<nodeid#portname>
86		86
87	A port ID is the concatenation of a node ID, a hash-mark (C<#>) as	87	A port ID is the concatenation of a node ID, a hash-mark (C<#>)
88	separator, and a port name (a printable string of unspecified format).	88	as separator, and a port name (a printable string of unspecified
		89	format created by AnyEvent::MP).
89		90
90	=item node	91	=item node
91		92
92	A node is a single process containing at least one port - the node port,	93	A node is a single process containing at least one port - the node port,
93	which enables nodes to manage each other remotely, and to create new	94	which enables nodes to manage each other remotely, and to create new
…		…
184	use common::sense;	185	use common::sense;
185		186
186	use Carp ();	187	use Carp ();
187		188
188	use AE ();	189	use AE ();
		190	use Guard ();
189		191
190	use base "Exporter";	192	use base "Exporter";
191		193
192	our $VERSION = $AnyEvent::MP::Config::VERSION;	194	our $VERSION = $AnyEvent::MP::Config::VERSION;
193		195
194	our @EXPORT = qw(	196	our @EXPORT = qw(
195	NODE $NODE *SELF node_of after	197	NODE $NODE *SELF node_of after
196	configure	198	configure
197	snd rcv mon mon_guard kil psub peval spawn cal	199	snd rcv mon mon_guard kil psub peval spawn cal
198	port	200	port
		201	db_set db_del db_reg
		202	db_mon db_family db_keys db_values
199	);	203	);
200		204
201	our $SELF;	205	our $SELF;
202		206
203	sub _self_die() {	207	sub _self_die() {
…		…
227		231
228	This function configures a node - it must be called exactly once (or	232	This function configures a node - it must be called exactly once (or
229	never) before calling other AnyEvent::MP functions.	233	never) before calling other AnyEvent::MP functions.
230		234
231	The key/value pairs are basically the same ones as documented for the	235	The key/value pairs are basically the same ones as documented for the
232	F<aemp> command line utility (sans the set/del prefix), with two additions:	236	F<aemp> command line utility (sans the set/del prefix), with these additions:
233		237
234	=over 4	238	=over 4
235		239
236	=item norc => $boolean (default false)	240	=item norc => $boolean (default false)
237		241
…		…
242	=item force => $boolean (default false)	246	=item force => $boolean (default false)
243		247
244	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
245	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
246	the rc file to override any options specified in the program.	250	the rc file to override any options specified in the program.
		251
		252	=item secure => $pass->(@msg)
		253
		254	In addition to specifying a boolean, you can specify a code reference that
		255	is called for every code execution attempt - the execution request is
		256	granted iff the callback returns a true value.
		257
		258	Most of the time the callback should look only at
		259	C<$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).
		262
		263	See F<semp setsecure> for more info.
247		264
248	=back	265	=back
249		266
250	=over 4	267	=over 4
251		268
…		…
267	That means that the values specified in the profile have highest priority	284	That means that the values specified in the profile have highest priority
268	and the values specified directly via C<configure> have lowest priority,	285	and the values specified directly via C<configure> have lowest priority,
269	and can only be used to specify defaults.	286	and can only be used to specify defaults.
270		287
271	If the profile specifies a node ID, then this will become the node ID of	288	If the profile specifies a node ID, then this will become the node ID of
272	this process. If not, then the profile name will be used as node ID. The	289	this process. If not, then the profile name will be used as node ID, with
273	special node ID of C<anon/> will be replaced by a random node ID.	290	a unique randoms tring (C</%u>) appended.
		291
		292	The node ID can contain some C<%> sequences that are expanded: C<%n>
		293	is expanded to the local nodename, C<%u> is replaced by a random
		294	strign to make the node unique. For example, the F<aemp> commandline
		295	utility uses C<aemp/%n/%u> as nodename, which might expand to
		296	C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>.
274		297
275	=item step 2, bind listener sockets	298	=item step 2, bind listener sockets
276		299
277	The next step is to look up the binds in the profile, followed by binding	300	The next step is to look up the binds in the profile, followed by binding
278	aemp protocol listeners on all binds specified (it is possible and valid	301	aemp protocol listeners on all binds specified (it is possible and valid
…		…
295	Example: become a distributed node using the local node name as profile.	318	Example: become a distributed node using the local node name as profile.
296	This should be the most common form of invocation for "daemon"-type nodes.	319	This should be the most common form of invocation for "daemon"-type nodes.
297		320
298	configure	321	configure
299		322
300	Example: become an anonymous node. This form is often used for commandline	323	Example: become a semi-anonymous node. This form is often used for
301	clients.	324	commandline clients.
302		325
303	configure nodeid => "anon/";	326	configure nodeid => "myscript/%n/%u";
304		327
305	Example: configure a node using a profile called seed, which is suitable	328	Example: configure a node using a profile called seed, which is suitable
306	for a seed node as it binds on all local addresses on a fixed port (4040,	329	for a seed node as it binds on all local addresses on a fixed port (4040,
307	customary for aemp).	330	customary for aemp).
308		331
309	# use the aemp commandline utility	332	# use the aemp commandline utility
310	# aemp profile seed nodeid anon/ binds '*:4040'	333	# aemp profile seed binds '*:4040'
311		334
312	# then use it	335	# then use it
313	configure profile => "seed";	336	configure profile => "seed";
314		337
315	# or simply use aemp from the shell again:	338	# or simply use aemp from the shell again:
…		…
380		403
381	=cut	404	=cut
382		405
383	sub rcv($@);	406	sub rcv($@);
384		407
385	sub _kilme {	408	my $KILME = sub {
386	die "received message on port without callback";	409	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
387	}	410	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		411	};
388		412
389	sub port(;&) {	413	sub port(;&) {
390	my $id = "$UNIQ." . ++$ID;	414	my $id = $UNIQ . ++$ID;
391	my $port = "$NODE#$id";	415	my $port = "$NODE#$id";
392		416
393	rcv $port, shift \|\| \&_kilme;	417	rcv $port, shift \|\| $KILME;
394		418
395	$port	419	$port
396	}	420	}
397		421
398	=item rcv $local_port, $callback->(@msg)	422	=item rcv $local_port, $callback->(@msg)
…		…
403		427
404	The global C<$SELF> (exported by this module) contains C<$port> while	428	The global C<$SELF> (exported by this module) contains C<$port> while
405	executing the callback. Runtime errors during callback execution will	429	executing the callback. Runtime errors during callback execution will
406	result in the port being C<kil>ed.	430	result in the port being C<kil>ed.
407		431
408	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
409	C<tag> match.	433	C<tag> match.
410		434
411	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	435	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
412		436
413	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
…		…
668	}	692	}
669		693
670	$node->monitor ($port, $cb);	694	$node->monitor ($port, $cb);
671		695
672	defined wantarray	696	defined wantarray
673	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })	697	and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
674	}	698	}
675		699
676	=item $guard = mon_guard $port, $ref, $ref...	700	=item $guard = mon_guard $port, $ref, $ref...
677		701
678	Monitors the given C<$port> and keeps the passed references. When the port	702	Monitors the given C<$port> and keeps the passed references. When the port
…		…
714	will be reported as reason C<< die => $@ >>.	738	will be reported as reason C<< die => $@ >>.
715		739
716	Transport/communication errors are reported as C<< transport_error =>	740	Transport/communication errors are reported as C<< transport_error =>
717	$message >>.	741	$message >>.
718		742
719	=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: $!";
720		754
721	=item $port = spawn $node, $initfunc[, @initdata]	755	=item $port = spawn $node, $initfunc[, @initdata]
722		756
723	Creates a port on the node C<$node> (which can also be a port ID, in which	757	Creates a port on the node C<$node> (which can also be a port ID, in which
724	case it's the node where that port resides).	758	case it's the node where that port resides).
…		…
782	}	816	}
783		817
784	sub spawn(@) {	818	sub spawn(@) {
785	my ($nodeid, undef) = split /#/, shift, 2;	819	my ($nodeid, undef) = split /#/, shift, 2;
786		820
787	my $id = "$RUNIQ." . ++$ID;	821	my $id = $RUNIQ . ++$ID;
788		822
789	$_[0] =~ /::/	823	$_[0] =~ /::/
790	or Carp::croak "spawn init function must be a fully-qualified name, caught";	824	or Carp::croak "spawn init function must be a fully-qualified name, caught";
791		825
792	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	826	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
…		…
816	ref $action[0]	850	ref $action[0]
817	? $action[0]()	851	? $action[0]()
818	: snd @action;	852	: snd @action;
819	};	853	};
820	}	854	}
		855
		856	#=item $cb2 = timeout $seconds, $cb[, @args]
821		857
822	=item cal $port, @msg, $callback[, $timeout]	858	=item cal $port, @msg, $callback[, $timeout]
823		859
824	A simple form of RPC - sends a message to the given C<$port> with the	860	A simple form of RPC - sends a message to the given C<$port> with the
825	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.
…		…
871	$port	907	$port
872	}	908	}
873		909
874	=back	910	=back
875		911
		912	=head1 DISTRIBUTED DATABASE
		913
		914	AnyEvent::MP comes with a simple distributed database. The database will
		915	be mirrored asynchronously on all global nodes. Other nodes bind to one
		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.
		919
		920	The database structure is that of a two-level hash - the database hash
		921	contains hashes which contain values, similarly to a perl hash of hashes,
		922	i.e.:
		923
		924	$DATABASE{$family}{$subkey} = $value
		925
		926	The top level hash key is called "family", and the second-level hash key
		927	is called "subkey" or simply "key".
		928
		929	The family must be alphanumeric, i.e. start with a letter and consist
		930	of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>,
		931	pretty much like Perl module names.
		932
		933	As the family namespace is global, it is recommended to prefix family names
		934	with the name of the application or module using it.
		935
		936	The subkeys must be non-empty strings, with no further restrictions.
		937
		938	The values should preferably be strings, but other perl scalars should
		939	work as well (such as C<undef>, arrays and hashes).
		940
		941	Every database entry is owned by one node - adding the same family/subkey
		942	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
		943	but the result might be nondeterministic, i.e. the key might have
		944	different values on different nodes.
		945
		946	Different subkeys in the same family can be owned by different nodes
		947	without problems, and in fact, this is the common method to create worker
		948	pools. For example, a worker port for image scaling might do this:
		949
		950	db_set my_image_scalers => $port;
		951
		952	And clients looking for an image scaler will want to get the
		953	C<my_image_scalers> keys from time to time:
		954
		955	db_keys my_image_scalers => sub {
		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.
		971
		972	=over
		973
		974	=item $guard = db_set $family => $subkey [=> $value]
		975
		976	Sets (or replaces) a key to the database - if C<$value> is omitted,
		977	C<undef> is used instead.
		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
		982	=item db_del $family => $subkey...
		983
		984	Deletes one or more subkeys from the database family.
		985
		986	=item $guard = db_reg $family => $port => $value
		987
		988	=item $guard = db_reg $family => $port
		989
		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	};
		1089
		1090	=cut
		1091
		1092	=back
		1093
876	=head1 AnyEvent::MP vs. Distributed Erlang	1094	=head1 AnyEvent::MP vs. Distributed Erlang
877		1095
878	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	1096	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
879	== aemp node, Erlang process == aemp port), so many of the documents and	1097	== aemp node, Erlang process == aemp port), so many of the documents and
880	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	1098	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
…		…
1034	Keeping your messages simple, concentrating on data structures rather than	1252	Keeping your messages simple, concentrating on data structures rather than
1035	objects, will keep your messages clean, tidy and efficient.	1253	objects, will keep your messages clean, tidy and efficient.
1036		1254
1037	=back	1255	=back
1038		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
1039	=head1 SEE ALSO	1338	=head1 SEE ALSO
1040		1339
1041	L<AnyEvent::MP::Intro> - a gentle introduction.	1340	L<AnyEvent::MP::Intro> - a gentle introduction.
1042		1341
1043	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 1.121 by root, Tue Feb 28 18:37:24 2012 UTC vs. Revision 1.137 by root, Wed Mar 21 23:48:39 2012 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.121 by root, Tue Feb 28 18:37:24 2012 UTC vs.
Revision 1.137 by root, Wed Mar 21 23:48:39 2012 UTC