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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.120 by root, Sun Feb 26 11:12:54 2012 UTC vs.
Revision 1.136 by root, Wed Mar 21 15:22:16 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 => $pass->(@msg)
		253
		254	In addition to specifying a boolean, you can specify a code reference that
		255	is called for every code execution attempt - the execution request is
		256	granted iff the callback returns a true value.
		257
		258	Most of the time the callback should look only at
		259	C<$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.
		264
		265	=back
231		266
232	=over 4	267	=over 4
233		268
234	=item step 1, gathering configuration from profiles	269	=item step 1, gathering configuration from profiles
235		270
…		…
249	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
250	and the values specified directly via C<configure> have lowest priority,	285	and the values specified directly via C<configure> have lowest priority,
251	and can only be used to specify defaults.	286	and can only be used to specify defaults.
252		287
253	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
254	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
255	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>.
256		297
257	=item step 2, bind listener sockets	298	=item step 2, bind listener sockets
258		299
259	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
260	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
…		…
277	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.
278	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.
279		320
280	configure	321	configure
281		322
282	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
283	clients.	324	commandline clients.
284		325
285	configure nodeid => "anon/";	326	configure nodeid => "myscript/%n/%u";
286		327
287	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
288	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,
289	customary for aemp).	330	customary for aemp).
290		331
291	# use the aemp commandline utility	332	# use the aemp commandline utility
292	# aemp profile seed nodeid anon/ binds '*:4040'	333	# aemp profile seed binds '*:4040'
293		334
294	# then use it	335	# then use it
295	configure profile => "seed";	336	configure profile => "seed";
296		337
297	# or simply use aemp from the shell again:	338	# or simply use aemp from the shell again:
…		…
362		403
363	=cut	404	=cut
364		405
365	sub rcv($@);	406	sub rcv($@);
366		407
367	sub _kilme {	408	my $KILME = sub {
368	die "received message on port without callback";	409	(my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
369	}	410	kil $SELF, unhandled_message => "no callback found for message '$tag'";
		411	};
370		412
371	sub port(;&) {	413	sub port(;&) {
372	my $id = "$UNIQ." . $ID++;	414	my $id = $UNIQ . ++$ID;
373	my $port = "$NODE#$id";	415	my $port = "$NODE#$id";
374		416
375	rcv $port, shift \|\| \&_kilme;	417	rcv $port, shift \|\| $KILME;
376		418
377	$port	419	$port
378	}	420	}
379		421
380	=item rcv $local_port, $callback->(@msg)	422	=item rcv $local_port, $callback->(@msg)
…		…
385		427
386	The global C<$SELF> (exported by this module) contains C<$port> while	428	The global C<$SELF> (exported by this module) contains C<$port> while
387	executing the callback. Runtime errors during callback execution will	429	executing the callback. Runtime errors during callback execution will
388	result in the port being C<kil>ed.	430	result in the port being C<kil>ed.
389		431
390	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
391	C<tag> match.	433	C<tag> match.
392		434
393	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...	435	=item rcv $local_port, tag => $callback->(@msg_without_tag), ...
394		436
395	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
…		…
650	}	692	}
651		693
652	$node->monitor ($port, $cb);	694	$node->monitor ($port, $cb);
653		695
654	defined wantarray	696	defined wantarray
655	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })	697	and ($cb += 0, Guard::guard { $node->unmonitor ($port, $cb) })
656	}	698	}
657		699
658	=item $guard = mon_guard $port, $ref, $ref...	700	=item $guard = mon_guard $port, $ref, $ref...
659		701
660	Monitors the given C<$port> and keeps the passed references. When the port	702	Monitors the given C<$port> and keeps the passed references. When the port
…		…
696	will be reported as reason C<< die => $@ >>.	738	will be reported as reason C<< die => $@ >>.
697		739
698	Transport/communication errors are reported as C<< transport_error =>	740	Transport/communication errors are reported as C<< transport_error =>
699	$message >>.	741	$message >>.
700		742
701	=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: $!";
702		754
703	=item $port = spawn $node, $initfunc[, @initdata]	755	=item $port = spawn $node, $initfunc[, @initdata]
704		756
705	Creates a port on the node C<$node> (which can also be a port ID, in which	757	Creates a port on the node C<$node> (which can also be a port ID, in which
706	case it's the node where that port resides).	758	case it's the node where that port resides).
…		…
764	}	816	}
765		817
766	sub spawn(@) {	818	sub spawn(@) {
767	my ($nodeid, undef) = split /#/, shift, 2;	819	my ($nodeid, undef) = split /#/, shift, 2;
768		820
769	my $id = "$RUNIQ." . $ID++;	821	my $id = $RUNIQ . ++$ID;
770		822
771	$_[0] =~ /::/	823	$_[0] =~ /::/
772	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";
773		825
774	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;	826	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
775		827
776	"$nodeid#$id"	828	"$nodeid#$id"
777	}	829	}
		830
778		831
779	=item after $timeout, @msg	832	=item after $timeout, @msg
780		833
781	=item after $timeout, $callback	834	=item after $timeout, $callback
782		835
…		…
797	ref $action[0]	850	ref $action[0]
798	? $action[0]()	851	? $action[0]()
799	: snd @action;	852	: snd @action;
800	};	853	};
801	}	854	}
		855
		856	#=item $cb2 = timeout $seconds, $cb[, @args]
802		857
803	=item cal $port, @msg, $callback[, $timeout]	858	=item cal $port, @msg, $callback[, $timeout]
804		859
805	A simple form of RPC - sends a message to the given C<$port> with the	860	A simple form of RPC - sends a message to the given C<$port> with the
806	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.
…		…
852	$port	907	$port
853	}	908	}
854		909
855	=back	910	=back
856		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 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	=item db_del $family => $subkey...
		980
		981	Deletes one or more subkeys from the database family.
		982
		983	=item $guard = db_reg $family => $subkey [=> $value]
		984
		985	Sets the key on the database and returns a guard. When the guard is
		986	destroyed, the key is deleted from the database. If C<$value> is missing,
		987	then C<undef> is used.
		988
		989	=item db_family $family => $cb->(\%familyhash)
		990
		991	Queries the named database C<$family> and call the callback with the
		992	family represented as a hash. You can keep and freely modify the hash.
		993
		994	=item db_keys $family => $cb->(\@keys)
		995
		996	Same as C<db_family>, except it only queries the family I<subkeys> and passes
		997	them as array reference to the callback.
		998
		999	=item db_values $family => $cb->(\@values)
		1000
		1001	Same as C<db_family>, except it only queries the family I<values> and passes them
		1002	as array reference to the callback.
		1003
		1004	=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted)
		1005
		1006	Creates a monitor on the given database family. Each time a key is set
		1007	or or is deleted the callback is called with a hash containing the
		1008	database family and three lists of added, changed and deleted subkeys,
		1009	respectively. If no keys have changed then the array reference might be
		1010	C<undef> or even missing.
		1011
		1012	If not called in void context, a guard object is returned that, when
		1013	destroyed, stops the monitor.
		1014
		1015	The family hash reference and the key arrays belong to AnyEvent::MP and
		1016	B<must not be modified or stored> by the callback. When in doubt, make a
		1017	copy.
		1018
		1019	As soon as possible after the monitoring starts, the callback will be
		1020	called with the intiial contents of the family, even if it is empty,
		1021	i.e. there will always be a timely call to the callback with the current
		1022	contents.
		1023
		1024	It is possible that the callback is called with a change event even though
		1025	the subkey is already present and the value has not changed.
		1026
		1027	The monitoring stops when the guard object is destroyed.
		1028
		1029	Example: on every change to the family "mygroup", print out all keys.
		1030
		1031	my $guard = db_mon mygroup => sub {
		1032	my ($family, $a, $c, $d) = @_;
		1033	print "mygroup members: ", (join " ", keys %$family), "\n";
		1034	};
		1035
		1036	Exmaple: wait until the family "My::Module::workers" is non-empty.
		1037
		1038	my $guard; $guard = db_mon My::Module::workers => sub {
		1039	my ($family, $a, $c, $d) = @_;
		1040	return unless %$family;
		1041	undef $guard;
		1042	print "My::Module::workers now nonempty\n";
		1043	};
		1044
		1045	Example: print all changes to the family "AnyRvent::Fantasy::Module".
		1046
		1047	my $guard = db_mon AnyRvent::Fantasy::Module => sub {
		1048	my ($family, $a, $c, $d) = @_;
		1049
		1050	print "+$_=$family->{$_}\n" for @$a;
		1051	print "*$_=$family->{$_}\n" for @$c;
		1052	print "-$_=$family->{$_}\n" for @$d;
		1053	};
		1054
		1055	=cut
		1056
		1057	=back
		1058
857	=head1 AnyEvent::MP vs. Distributed Erlang	1059	=head1 AnyEvent::MP vs. Distributed Erlang
858		1060
859	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	1061	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	1062	== 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	1063	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.120 by root, Sun Feb 26 11:12:54 2012 UTC vs. Revision 1.136 by root, Wed Mar 21 15:22:16 2012 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.120 by root, Sun Feb 26 11:12:54 2012 UTC vs.
Revision 1.136 by root, Wed Mar 21 15:22:16 2012 UTC