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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.123 by root, Thu Mar 1 19:37:59 2012 UTC vs.
Revision 1.134 by root, Mon Mar 12 14:47:23 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
…		…
185	use common::sense;	185	use common::sense;
186		186
187	use Carp ();	187	use Carp ();
188		188
189	use AE ();	189	use AE ();
		190	use Guard ();
190		191
191	use base "Exporter";	192	use base "Exporter";
192		193
193	our $VERSION = $AnyEvent::MP::Config::VERSION;	194	our $VERSION = $AnyEvent::MP::Config::VERSION;
194		195
195	our @EXPORT = qw(	196	our @EXPORT = qw(
196	NODE $NODE *SELF node_of after	197	NODE $NODE *SELF node_of after
197	configure	198	configure
198	snd rcv mon mon_guard kil psub peval spawn cal	199	snd rcv mon mon_guard kil psub peval spawn cal
199	port	200	port
		201	db_set db_del db_reg
		202	db_mon db_family db_keys db_values
200	);	203	);
201		204
202	our $SELF;	205	our $SELF;
203		206
204	sub _self_die() {	207	sub _self_die() {
…		…
228		231
229	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
230	never) before calling other AnyEvent::MP functions.	233	never) before calling other AnyEvent::MP functions.
231		234
232	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
233	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:
234		237
235	=over 4	238	=over 4
236		239
237	=item norc => $boolean (default false)	240	=item norc => $boolean (default false)
238		241
…		…
243	=item force => $boolean (default false)	246	=item force => $boolean (default false)
244		247
245	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
246	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
247	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 => $pass->($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.
248		259
249	=back	260	=back
250		261
251	=over 4	262	=over 4
252		263
…		…
269	and the values specified directly via C<configure> have lowest priority,	280	and the values specified directly via C<configure> have lowest priority,
270	and can only be used to specify defaults.	281	and can only be used to specify defaults.
271		282
272	If the profile specifies a node ID, then this will become the node ID of	283	If the profile specifies a node ID, then this will become the node ID of
273	this process. If not, then the profile name will be used as node ID, with	284	this process. If not, then the profile name will be used as node ID, with
274	a slash (C</>) attached.	285	a unique randoms tring (C</%u>) appended.
275		286
276	If the node ID (or profile name) ends with a slash (C</>), then a random	287	The node ID can contain some C<%> sequences that are expanded: C<%n>
277	string is appended to make it unique.	288	is expanded to the local nodename, C<%u> is replaced by a random
		289	strign to make the node unique. For example, the F<aemp> commandline
		290	utility uses C<aemp/%n/%u> as nodename, which might expand to
		291	C<aemp/cerebro/ZQDGSIkRhEZQDGSIkRhE>.
278		292
279	=item step 2, bind listener sockets	293	=item step 2, bind listener sockets
280		294
281	The next step is to look up the binds in the profile, followed by binding	295	The next step is to look up the binds in the profile, followed by binding
282	aemp protocol listeners on all binds specified (it is possible and valid	296	aemp protocol listeners on all binds specified (it is possible and valid
…		…
299	Example: become a distributed node using the local node name as profile.	313	Example: become a distributed node using the local node name as profile.
300	This should be the most common form of invocation for "daemon"-type nodes.	314	This should be the most common form of invocation for "daemon"-type nodes.
301		315
302	configure	316	configure
303		317
304	Example: become an anonymous node. This form is often used for commandline	318	Example: become a semi-anonymous node. This form is often used for
305	clients.	319	commandline clients.
306		320
307	configure nodeid => "anon/";	321	configure nodeid => "myscript/%n/%u";
308		322
309	Example: configure a node using a profile called seed, which is suitable	323	Example: configure a node using a profile called seed, which is suitable
310	for a seed node as it binds on all local addresses on a fixed port (4040,	324	for a seed node as it binds on all local addresses on a fixed port (4040,
311	customary for aemp).	325	customary for aemp).
312		326
…		…
384		398
385	=cut	399	=cut
386		400
387	sub rcv($@);	401	sub rcv($@);
388		402
389	sub _kilme {	403	my $KILME = sub {
390	die "received message on port without callback";	404	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
391	}	405	kil $SELF, unhandled_message => "missing (tag or fallback) callback for message '$tag'";
		406	};
392		407
393	sub port(;&) {	408	sub port(;&) {
394	my $id = $UNIQ . ++$ID;	409	my $id = $UNIQ . ++$ID;
395	my $port = "$NODE#$id";	410	my $port = "$NODE#$id";
396		411
397	rcv $port, shift \|\| \&_kilme;	412	rcv $port, shift \|\| $KILME;
398		413
399	$port	414	$port
400	}	415	}
401		416
402	=item rcv $local_port, $callback->(@msg)	417	=item rcv $local_port, $callback->(@msg)
…		…
407		422
408	The global C<$SELF> (exported by this module) contains C<$port> while	423	The global C<$SELF> (exported by this module) contains C<$port> while
409	executing the callback. Runtime errors during callback execution will	424	executing the callback. Runtime errors during callback execution will
410	result in the port being C<kil>ed.	425	result in the port being C<kil>ed.
411		426
412	The default callback received all messages not matched by a more specific	427	The default callback receives all messages not matched by a more specific
413	C<tag> match.	428	C<tag> match.
414		429
415	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	430	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
416		431
417	Register (or replace) callbacks to be called on messages starting with the	432	Register (or replace) callbacks to be called on messages starting with the
…		…
672	}	687	}
673		688
674	$node->monitor ($port, $cb);	689	$node->monitor ($port, $cb);
675		690
676	defined wantarray	691	defined wantarray
677	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })	692	and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
678	}	693	}
679		694
680	=item $guard = mon_guard $port, $ref, $ref...	695	=item $guard = mon_guard $port, $ref, $ref...
681		696
682	Monitors the given C<$port> and keeps the passed references. When the port	697	Monitors the given C<$port> and keeps the passed references. When the port
…		…
718	will be reported as reason C<< die => $@ >>.	733	will be reported as reason C<< die => $@ >>.
719		734
720	Transport/communication errors are reported as C<< transport_error =>	735	Transport/communication errors are reported as C<< transport_error =>
721	$message >>.	736	$message >>.
722		737
723	=cut	738	Common idioms:
		739
		740	# silently remove yourself, do not kill linked ports
		741	kil $SELF;
		742
		743	# report a failure in some detail
		744	kil $SELF, failure_mode_1 => "it failed with too high temperature";
		745
		746	# do not waste much time with killing, just die when something goes wrong
		747	open my $fh, "<file"
		748	or die "file: $!";
724		749
725	=item $port = spawn $node, $initfunc[, @initdata]	750	=item $port = spawn $node, $initfunc[, @initdata]
726		751
727	Creates a port on the node C<$node> (which can also be a port ID, in which	752	Creates a port on the node C<$node> (which can also be a port ID, in which
728	case it's the node where that port resides).	753	case it's the node where that port resides).
…		…
820	ref $action[0]	845	ref $action[0]
821	? $action[0]()	846	? $action[0]()
822	: snd @action;	847	: snd @action;
823	};	848	};
824	}	849	}
		850
		851	#=item $cb2 = timeout $seconds, $cb[, @args]
825		852
826	=item cal $port, @msg, $callback[, $timeout]	853	=item cal $port, @msg, $callback[, $timeout]
827		854
828	A simple form of RPC - sends a message to the given C<$port> with the	855	A simple form of RPC - sends a message to the given C<$port> with the
829	given contents (C<@msg>), but adds a reply port to the message.	856	given contents (C<@msg>), but adds a reply port to the message.
…		…
875	$port	902	$port
876	}	903	}
877		904
878	=back	905	=back
879		906
		907	=head1 DISTRIBUTED DATABASE
		908
		909	AnyEvent::MP comes with a simple distributed database. The database will
		910	be mirrored asynchronously on all global nodes. Other nodes bind to one
		911	of the global nodes for their needs. Every node has a "local database"
		912	which contains all the values that are set locally. All local databases
		913	are merged together to form the global database, which can be queried.
		914
		915	The database structure is that of a two-level hash - the database hash
		916	contains hashes which contain values, similarly to a perl hash of hashes,
		917	i.e.:
		918
		919	$DATABASE{$family}{$subkey} = $value
		920
		921	The top level hash key is called "family", and the second-level hash key
		922	is called "subkey" or simply "key".
		923
		924	The family must be alphanumeric, i.e. start with a letter and consist
		925	of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>,
		926	pretty much like Perl module names.
		927
		928	As the family namespace is global, it is recommended to prefix family names
		929	with the name of the application or module using it.
		930
		931	The subkeys must be non-empty strings, with no further restrictions.
		932
		933	The values should preferably be strings, but other perl scalars should
		934	work as well (such as C<undef>, arrays and hashes).
		935
		936	Every database entry is owned by one node - adding the same family/subkey
		937	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
		938	but the result might be nondeterministic, i.e. the key might have
		939	different values on different nodes.
		940
		941	Different subkeys in the same family can be owned by different nodes
		942	without problems, and in fact, this is the common method to create worker
		943	pools. For example, a worker port for image scaling might do this:
		944
		945	db_set my_image_scalers => $port;
		946
		947	And clients looking for an image scaler will want to get the
		948	C<my_image_scalers> keys from time to time:
		949
		950	db_keys my_image_scalers => sub {
		951	@ports = @{ $_[0] };
		952	};
		953
		954	Or better yet, they want to monitor the database family, so they always
		955	have a reasonable up-to-date copy:
		956
		957	db_mon my_image_scalers => sub {
		958	@ports = keys %{ $_[0] };
		959	};
		960
		961	In general, you can set or delete single subkeys, but query and monitor
		962	whole families only.
		963
		964	If you feel the need to monitor or query a single subkey, try giving it
		965	it's own family.
		966
		967	=over
		968
		969	=item db_set $family => $subkey [=> $value]
		970
		971	Sets (or replaces) a key to the database - if C<$value> is omitted,
		972	C<undef> is used instead.
		973
		974	=item db_del $family => $subkey...
		975
		976	Deletes one or more subkeys from the database family.
		977
		978	=item $guard = db_reg $family => $subkey [=> $value]
		979
		980	Sets the key on the database and returns a guard. When the guard is
		981	destroyed, the key is deleted from the database. If C<$value> is missing,
		982	then C<undef> is used.
		983
		984	=item db_family $family => $cb->(\%familyhash)
		985
		986	Queries the named database C<$family> and call the callback with the
		987	family represented as a hash. You can keep and freely modify the hash.
		988
		989	=item db_keys $family => $cb->(\@keys)
		990
		991	Same as C<db_family>, except it only queries the family I<subkeys> and passes
		992	them as array reference to the callback.
		993
		994	=item db_values $family => $cb->(\@values)
		995
		996	Same as C<db_family>, except it only queries the family I<values> and passes them
		997	as array reference to the callback.
		998
		999	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)
		1000
		1001	Creates a monitor on the given database family. Each time a key is set
		1002	or or is deleted the callback is called with a hash containing the
		1003	database family and three lists of added, changed and deleted subkeys,
		1004	respectively. If no keys have changed then the array reference might be
		1005	C<undef> or even missing.
		1006
		1007	If not called in void context, a guard object is returned that, when
		1008	destroyed, stops the monitor.
		1009
		1010	The family hash reference and the key arrays belong to AnyEvent::MP and
		1011	B<must not be modified or stored> by the callback. When in doubt, make a
		1012	copy.
		1013
		1014	As soon as possible after the monitoring starts, the callback will be
		1015	called with the intiial contents of the family, even if it is empty,
		1016	i.e. there will always be a timely call to the callback with the current
		1017	contents.
		1018
		1019	It is possible that the callback is called with a change event even though
		1020	the subkey is already present and the value has not changed.
		1021
		1022	The monitoring stops when the guard object is destroyed.
		1023
		1024	Example: on every change to the family "mygroup", print out all keys.
		1025
		1026	my $guard = db_mon mygroup => sub {
		1027	my ($family, $a, $c, $d) = @_;
		1028	print "mygroup members: ", (join " ", keys %$family), "\n";
		1029	};
		1030
		1031	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1032
		1033	my $guard; $guard = db_mon My::Module::workers => sub {
		1034	my ($family, $a, $c, $d) = @_;
		1035	return unless %$family;
		1036	undef $guard;
		1037	print "My::Module::workers now nonempty\n";
		1038	};
		1039
		1040	Example: print all changes to the family "AnyRvent::Fantasy::Module".
		1041
		1042	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
		1043	my ($family, $a, $c, $d) = @_;
		1044
		1045	print "+$_=$family->{$_}\n" for @$a;
		1046	print "*$_=$family->{$_}\n" for @$c;
		1047	print "-$_=$family->{$_}\n" for @$d;
		1048	};
		1049
		1050	=cut
		1051
		1052	=back
		1053
880	=head1 AnyEvent::MP vs. Distributed Erlang	1054	=head1 AnyEvent::MP vs. Distributed Erlang
881		1055
882	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	1056	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
883	== aemp node, Erlang process == aemp port), so many of the documents and	1057	== aemp node, Erlang process == aemp port), so many of the documents and
884	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	1058	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.123 by root, Thu Mar 1 19:37:59 2012 UTC vs. Revision 1.134 by root, Mon Mar 12 14:47:23 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.123 by root, Thu Mar 1 19:37:59 2012 UTC vs.
Revision 1.134 by root, Mon Mar 12 14:47:23 2012 UTC