[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 1.132 by root, Sat Mar 10 20:34:11 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 => $pass->($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.
247		259
248	=back	260	=back
249		261
250	=over 4	262	=over 4
251		263
…		…
267	That means that the values specified in the profile have highest priority	279	That means that the values specified in the profile have highest priority
268	and the values specified directly via C<configure> have lowest priority,	280	and the values specified directly via C<configure> have lowest priority,
269	and can only be used to specify defaults.	281	and can only be used to specify defaults.
270		282
271	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
272	this process. If not, then the profile name will be used as node ID. The	284	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.	285	a unique randoms tring (C</%u>) appended.
		286
		287	The node ID can contain some C<%> sequences that are expanded: C<%n>
		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>.
274		292
275	=item step 2, bind listener sockets	293	=item step 2, bind listener sockets
276		294
277	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
278	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
…		…
295	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.
296	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.
297		315
298	configure	316	configure
299		317
300	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
301	clients.	319	commandline clients.
302		320
303	configure nodeid => "anon/";	321	configure nodeid => "myscript/%n/%u";
304		322
305	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
306	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,
307	customary for aemp).	325	customary for aemp).
308		326
309	# use the aemp commandline utility	327	# use the aemp commandline utility
310	# aemp profile seed nodeid anon/ binds '*:4040'	328	# aemp profile seed binds '*:4040'
311		329
312	# then use it	330	# then use it
313	configure profile => "seed";	331	configure profile => "seed";
314		332
315	# or simply use aemp from the shell again:	333	# or simply use aemp from the shell again:
…		…
380		398
381	=cut	399	=cut
382		400
383	sub rcv($@);	401	sub rcv($@);
384		402
385	sub _kilme {	403	my $KILME = sub {
386	die "received message on port without callback";	404	die "received message on port without callback";
387	}	405	};
388		406
389	sub port(;&) {	407	sub port(;&) {
390	my $id = "$UNIQ." . ++$ID;	408	my $id = $UNIQ . ++$ID;
391	my $port = "$NODE#$id";	409	my $port = "$NODE#$id";
392		410
393	rcv $port, shift \|\| \&_kilme;	411	rcv $port, shift \|\| $KILME;
394		412
395	$port	413	$port
396	}	414	}
397		415
398	=item rcv $local_port, $callback->(@msg)	416	=item rcv $local_port, $callback->(@msg)
…		…
668	}	686	}
669		687
670	$node->monitor ($port, $cb);	688	$node->monitor ($port, $cb);
671		689
672	defined wantarray	690	defined wantarray
673	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })	691	and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
674	}	692	}
675		693
676	=item $guard = mon_guard $port, $ref, $ref...	694	=item $guard = mon_guard $port, $ref, $ref...
677		695
678	Monitors the given C<$port> and keeps the passed references. When the port	696	Monitors the given C<$port> and keeps the passed references. When the port
…		…
782	}	800	}
783		801
784	sub spawn(@) {	802	sub spawn(@) {
785	my ($nodeid, undef) = split /#/, shift, 2;	803	my ($nodeid, undef) = split /#/, shift, 2;
786		804
787	my $id = "$RUNIQ." . ++$ID;	805	my $id = $RUNIQ . ++$ID;
788		806
789	$_[0] =~ /::/	807	$_[0] =~ /::/
790	or Carp::croak "spawn init function must be a fully-qualified name, caught";	808	or Carp::croak "spawn init function must be a fully-qualified name, caught";
791		809
792	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	810	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
…		…
816	ref $action[0]	834	ref $action[0]
817	? $action[0]()	835	? $action[0]()
818	: snd @action;	836	: snd @action;
819	};	837	};
820	}	838	}
		839
		840	#=item $cb2 = timeout $seconds, $cb[, @args]
821		841
822	=item cal $port, @msg, $callback[, $timeout]	842	=item cal $port, @msg, $callback[, $timeout]
823		843
824	A simple form of RPC - sends a message to the given C<$port> with the	844	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.	845	given contents (C<@msg>), but adds a reply port to the message.
…		…
871	$port	891	$port
872	}	892	}
873		893
874	=back	894	=back
875		895
		896	=head1 DISTRIBUTED DATABASE
		897
		898	AnyEvent::MP comes with a simple distributed database. The database will
		899	be mirrored asynchronously on all global nodes. Other nodes bind to one
		900	of the global nodes for their needs. Every node has a "local database"
		901	which contains all the values that are set locally. All local databases
		902	are merged together to form the global database, which can be queried.
		903
		904	The database structure is that of a two-level hash - the database hash
		905	contains hashes which contain values, similarly to a perl hash of hashes,
		906	i.e.:
		907
		908	$DATABASE{$family}{$subkey} = $value
		909
		910	The top level hash key is called "family", and the second-level hash key
		911	is called "subkey" or simply "key".
		912
		913	The family must be alphanumeric, i.e. start with a letter and consist
		914	of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>,
		915	pretty much like Perl module names.
		916
		917	As the family namespace is global, it is recommended to prefix family names
		918	with the name of the application or module using it.
		919
		920	The subkeys must be non-empty strings, with no further restrictions.
		921
		922	The values should preferably be strings, but other perl scalars should
		923	work as well (such as C<undef>, arrays and hashes).
		924
		925	Every database entry is owned by one node - adding the same family/subkey
		926	combination on multiple nodes will not cause discomfort for AnyEvent::MP,
		927	but the result might be nondeterministic, i.e. the key might have
		928	different values on different nodes.
		929
		930	Different subkeys in the same family can be owned by different nodes
		931	without problems, and in fact, this is the common method to create worker
		932	pools. For example, a worker port for image scaling might do this:
		933
		934	db_set my_image_scalers => $port;
		935
		936	And clients looking for an image scaler will want to get the
		937	C<my_image_scalers> keys from time to time:
		938
		939	db_keys my_image_scalers => sub {
		940	@ports = @{ $_[0] };
		941	};
		942
		943	Or better yet, they want to monitor the database family, so they always
		944	have a reasonable up-to-date copy:
		945
		946	db_mon my_image_scalers => sub {
		947	@ports = keys %{ $_[0] };
		948	};
		949
		950	In general, you can set or delete single subkeys, but query and monitor
		951	whole families only.
		952
		953	If you feel the need to monitor or query a single subkey, try giving it
		954	it's own family.
		955
		956	=over
		957
		958	=item db_set $family => $subkey [=> $value]
		959
		960	Sets (or replaces) a key to the database - if C<$value> is omitted,
		961	C<undef> is used instead.
		962
		963	=item db_del $family => $subkey...
		964
		965	Deletes one or more subkeys from the database family.
		966
		967	=item $guard = db_reg $family => $subkey [=> $value]
		968
		969	Sets the key on the database and returns a guard. When the guard is
		970	destroyed, the key is deleted from the database. If C<$value> is missing,
		971	then C<undef> is used.
		972
		973	=item db_family $family => $cb->(\%familyhash)
		974
		975	Queries the named database C<$family> and call the callback with the
		976	family represented as a hash. You can keep and freely modify the hash.
		977
		978	=item db_keys $family => $cb->(\@keys)
		979
		980	Same as C<db_family>, except it only queries the family I<subkeys> and passes
		981	them as array reference to the callback.
		982
		983	=item db_values $family => $cb->(\@values)
		984
		985	Same as C<db_family>, except it only queries the family I<values> and passes them
		986	as array reference to the callback.
		987
		988	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)
		989
		990	Creates a monitor on the given database family. Each time a key is set
		991	or or is deleted the callback is called with a hash containing the
		992	database family and three lists of added, changed and deleted subkeys,
		993	respectively. If no keys have changed then the array reference might be
		994	C<undef> or even missing.
		995
		996	If not called in void context, a guard object is returned that, when
		997	destroyed, stops the monitor.
		998
		999	The family hash reference and the key arrays belong to AnyEvent::MP and
		1000	B<must not be modified or stored> by the callback. When in doubt, make a
		1001	copy.
		1002
		1003	As soon as possible after the monitoring starts, the callback will be
		1004	called with the intiial contents of the family, even if it is empty,
		1005	i.e. there will always be a timely call to the callback with the current
		1006	contents.
		1007
		1008	It is possible that the callback is called with a change event even though
		1009	the subkey is already present and the value has not changed.
		1010
		1011	The monitoring stops when the guard object is destroyed.
		1012
		1013	Example: on every change to the family "mygroup", print out all keys.
		1014
		1015	my $guard = db_mon mygroup => sub {
		1016	my ($family, $a, $c, $d) = @_;
		1017	print "mygroup members: ", (join " ", keys %$family), "\n";
		1018	};
		1019
		1020	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1021
		1022	my $guard; $guard = db_mon My::Module::workers => sub {
		1023	my ($family, $a, $c, $d) = @_;
		1024	return unless %$family;
		1025	undef $guard;
		1026	print "My::Module::workers now nonempty\n";
		1027	};
		1028
		1029	Example: print all changes to the family "AnyRvent::Fantasy::Module".
		1030
		1031	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
		1032	my ($family, $a, $c, $d) = @_;
		1033
		1034	print "+$_=$family->{$_}\n" for @$a;
		1035	print "*$_=$family->{$_}\n" for @$c;
		1036	print "-$_=$family->{$_}\n" for @$d;
		1037	};
		1038
		1039	=cut
		1040
		1041	=back
		1042
876	=head1 AnyEvent::MP vs. Distributed Erlang	1043	=head1 AnyEvent::MP vs. Distributed Erlang
877		1044
878	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	1045	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	1046	== 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	1047	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.121 by root, Tue Feb 28 18:37:24 2012 UTC vs. Revision 1.132 by root, Sat Mar 10 20:34:11 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.121 by root, Tue Feb 28 18:37:24 2012 UTC vs.
Revision 1.132 by root, Sat Mar 10 20:34:11 2012 UTC