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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.119 by root, Sun Feb 26 10:29:59 2012 UTC vs.
Revision 1.131 by root, Fri Mar 9 19:07:53 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
…		…
175		176
176	=cut	177	=cut
177		178
178	package AnyEvent::MP;	179	package AnyEvent::MP;
179		180
		181	use AnyEvent::MP::Config ();
180	use AnyEvent::MP::Kernel;	182	use AnyEvent::MP::Kernel;
		183	use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID);
181		184
182	use common::sense;	185	use common::sense;
183		186
184	use Carp ();	187	use Carp ();
185		188
186	use AE ();	189	use AE ();
		190	use Guard ();
187		191
188	use base "Exporter";	192	use base "Exporter";
189		193
190	our $VERSION = '1.30';	194	our $VERSION = $AnyEvent::MP::Config::VERSION;
191		195
192	our @EXPORT = qw(	196	our @EXPORT = qw(
193	NODE $NODE *SELF node_of after	197	NODE $NODE *SELF node_of after
194	configure	198	configure
195	snd rcv mon mon_guard kil psub peval spawn cal	199	snd rcv mon mon_guard kil psub peval spawn cal
196	port	200	port
		201	db_set db_del db_reg
		202	db_mon db_family db_keys db_values
197	);	203	);
198		204
199	our $SELF;	205	our $SELF;
200		206
201	sub _self_die() {	207	sub _self_die() {
…		…
221	Before a node can talk to other nodes on the network (i.e. enter	227	Before a node can talk to other nodes on the network (i.e. enter
222	"distributed mode") it has to configure itself - the minimum a node needs	228	"distributed mode") it has to configure itself - the minimum a node needs
223	to know is its own name, and optionally it should know the addresses of	229	to know is its own name, and optionally it should know the addresses of
224	some other nodes in the network to discover other nodes.	230	some other nodes in the network to discover other nodes.
225		231
226	The key/value pairs are basically the same ones as documented for the
227	F<aemp> command line utility (sans the set/del prefix).
228
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.
		234
		235	The key/value pairs are basically the same ones as documented for the
		236	F<aemp> command line utility (sans the set/del prefix), with these additions:
		237
		238	=over 4
		239
		240	=item norc => $boolean (default false)
		241
		242	If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
		243	be consulted - all configuraiton options must be specified in the
		244	C<configure> call.
		245
		246	=item force => $boolean (default false)
		247
		248	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
		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.
		259
		260	=back
231		261
232	=over 4	262	=over 4
233		263
234	=item step 1, gathering configuration from profiles	264	=item step 1, gathering configuration from profiles
235		265
…		…
249	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
250	and the values specified directly via C<configure> have lowest priority,	280	and the values specified directly via C<configure> have lowest priority,
251	and can only be used to specify defaults.	281	and can only be used to specify defaults.
252		282
253	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
254	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
255	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>.
256		292
257	=item step 2, bind listener sockets	293	=item step 2, bind listener sockets
258		294
259	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
260	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
…		…
277	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.
278	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.
279		315
280	configure	316	configure
281		317
282	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
283	clients.	319	commandline clients.
284		320
285	configure nodeid => "anon/";	321	configure nodeid => "myscript/%n/%u";
286		322
287	Example: configure a node using a profile called seed, which si suitable	323	Example: configure a node using a profile called seed, which is suitable
288	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,
289	customary for aemp).	325	customary for aemp).
290		326
291	# use the aemp commandline utility	327	# use the aemp commandline utility
292	# aemp profile seed nodeid anon/ binds '*:4040'	328	# aemp profile seed binds '*:4040'
293		329
294	# then use it	330	# then use it
295	configure profile => "seed";	331	configure profile => "seed";
296		332
297	# or simply use aemp from the shell again:	333	# or simply use aemp from the shell again:
…		…
367	sub _kilme {	403	sub _kilme {
368	die "received message on port without callback";	404	die "received message on port without callback";
369	}	405	}
370		406
371	sub port(;&) {	407	sub port(;&) {
372	my $id = "$UNIQ." . $ID++;	408	my $id = $UNIQ . ++$ID;
373	my $port = "$NODE#$id";	409	my $port = "$NODE#$id";
374		410
375	rcv $port, shift \|\| \&_kilme;	411	rcv $port, shift \|\| \&_kilme;
376		412
377	$port	413	$port
…		…
650	}	686	}
651		687
652	$node->monitor ($port, $cb);	688	$node->monitor ($port, $cb);
653		689
654	defined wantarray	690	defined wantarray
655	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })	691	and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
656	}	692	}
657		693
658	=item $guard = mon_guard $port, $ref, $ref...	694	=item $guard = mon_guard $port, $ref, $ref...
659		695
660	Monitors the given C<$port> and keeps the passed references. When the port	696	Monitors the given C<$port> and keeps the passed references. When the port
…		…
764	}	800	}
765		801
766	sub spawn(@) {	802	sub spawn(@) {
767	my ($nodeid, undef) = split /#/, shift, 2;	803	my ($nodeid, undef) = split /#/, shift, 2;
768		804
769	my $id = "$RUNIQ." . $ID++;	805	my $id = $RUNIQ . ++$ID;
770		806
771	$_[0] =~ /::/	807	$_[0] =~ /::/
772	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";
773		809
774	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	810	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
775		811
776	"$nodeid#$id"	812	"$nodeid#$id"
777	}	813	}
		814
778		815
779	=item after $timeout, @msg	816	=item after $timeout, @msg
780		817
781	=item after $timeout, $callback	818	=item after $timeout, $callback
782		819
…		…
797	ref $action[0]	834	ref $action[0]
798	? $action[0]()	835	? $action[0]()
799	: snd @action;	836	: snd @action;
800	};	837	};
801	}	838	}
		839
		840	#=item $cb2 = timeout $seconds, $cb[, @args]
802		841
803	=item cal $port, @msg, $callback[, $timeout]	842	=item cal $port, @msg, $callback[, $timeout]
804		843
805	A simple form of RPC - sends a message to the given C<$port> with the	844	A simple form of RPC - sends a message to the given C<$port> with the
806	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.
…		…
852	$port	891	$port
853	}	892	}
854		893
855	=back	894	=back
856		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	The family hash reference and the key arrays belong to AnyEvent::MP and
		997	B<must not be modified or stored> by the callback. When in doubt, make a
		998	copy.
		999
		1000	As soon as possible after the monitoring starts, the callback will be
		1001	called with the intiial contents of the family, even if it is empty,
		1002	i.e. there will always be a timely call to the callback with the current
		1003	contents.
		1004
		1005	It is possible that the callback is called with a change event even though
		1006	the subkey is already present and the value has not changed.
		1007
		1008	The monitoring stops when the guard object is destroyed.
		1009
		1010	Example: on every change to the family "mygroup", print out all keys.
		1011
		1012	my $guard = db_mon mygroup => sub {
		1013	my ($family, $a, $c, $d) = @_;
		1014	print "mygroup members: ", (join " ", keys %$family), "\n";
		1015	};
		1016
		1017	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1018
		1019	my $guard; $guard = db_mon My::Module::workers => sub {
		1020	my ($family, $a, $c, $d) = @_;
		1021	return unless %$family;
		1022	undef $guard;
		1023	print "My::Module::workers now nonempty\n";
		1024	};
		1025
		1026	Example: print all changes to the family "AnyRvent::Fantasy::Module".
		1027
		1028	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
		1029	my ($family, $a, $c, $d) = @_;
		1030
		1031	print "+$_=$family->{$_}\n" for @$a;
		1032	print "*$_=$family->{$_}\n" for @$c;
		1033	print "-$_=$family->{$_}\n" for @$d;
		1034	};
		1035
		1036	=cut
		1037
		1038	=back
		1039
857	=head1 AnyEvent::MP vs. Distributed Erlang	1040	=head1 AnyEvent::MP vs. Distributed Erlang
858		1041
859	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	1042	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
860	== aemp node, Erlang process == aemp port), so many of the documents and	1043	== aemp node, Erlang process == aemp port), so many of the documents and
861	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	1044	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.119 by root, Sun Feb 26 10:29:59 2012 UTC vs. Revision 1.131 by root, Fri Mar 9 19:07:53 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.119 by root, Sun Feb 26 10:29:59 2012 UTC vs.
Revision 1.131 by root, Fri Mar 9 19:07:53 2012 UTC