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Revision 1.145 by root, Tue Oct 2 13:58:07 2012 UTC

47 # execute callbacks in $SELF port context 47 # execute callbacks in $SELF port context
48 my $timer = AE::timer 1, 0, psub { 48 my $timer = AE::timer 1, 0, psub {
49 die "kill the port, delayed"; 49 die "kill the port, delayed";
50 }; 50 };
51 51
52=head1 CURRENT STATUS 52 # distributed database - modification
53 db_set $family => $subkey [=> $value] # add a subkey
54 db_del $family => $subkey... # delete one or more subkeys
55 db_reg $family => $port [=> $value] # register a port
53 56
54 bin/aemp - stable. 57 # distributed database - queries
55 AnyEvent::MP - stable API, should work. 58 db_family $family => $cb->(\%familyhash)
56 AnyEvent::MP::Intro - explains most concepts. 59 db_keys $family => $cb->(\@keys)
57 AnyEvent::MP::Kernel - mostly stable API. 60 db_values $family => $cb->(\@values)
58 AnyEvent::MP::Global - stable API. 61
62 # distributed database - monitoring a family
63 db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
59 64
60=head1 DESCRIPTION 65=head1 DESCRIPTION
61 66
62This module (-family) implements a simple message passing framework. 67This module (-family) implements a simple message passing framework.
63 68
178 183
179package AnyEvent::MP; 184package AnyEvent::MP;
180 185
181use AnyEvent::MP::Config (); 186use AnyEvent::MP::Config ();
182use AnyEvent::MP::Kernel; 187use AnyEvent::MP::Kernel;
183use AnyEvent::MP::Kernel qw(%NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID); 188use AnyEvent::MP::Kernel qw(
189 %NODE %PORT %PORT_DATA $UNIQ $RUNIQ $ID
190 add_node load_func
191
192 NODE $NODE
193 configure
194 node_of port_is_local
195 snd kil
196 db_set db_del
197 db_mon db_family db_keys db_values
198);
184 199
185use common::sense; 200use common::sense;
186 201
187use Carp (); 202use Carp ();
188 203
189use AE (); 204use AnyEvent ();
190use Guard (); 205use Guard ();
191 206
192use base "Exporter"; 207use base "Exporter";
193 208
194our $VERSION = $AnyEvent::MP::Config::VERSION; 209our $VERSION = $AnyEvent::MP::Config::VERSION;
195 210
196our @EXPORT = qw( 211our @EXPORT = qw(
197 NODE $NODE *SELF node_of after 212 NODE $NODE
198 configure 213 configure
214 node_of port_is_local
215 snd kil
216 db_set db_del
217 db_mon db_family db_keys db_values
218
219 *SELF
220
199 snd rcv mon mon_guard kil psub peval spawn cal 221 port rcv mon mon_guard psub peval spawn cal
200 port
201 db_set db_del db_reg 222 db_set db_del db_reg
202 db_mon db_family db_keys db_values 223 db_mon db_family db_keys db_values
224
225 after
203); 226);
204 227
205our $SELF; 228our $SELF;
206 229
207sub _self_die() { 230sub _self_die() {
218 241
219=item $nodeid = node_of $port 242=item $nodeid = node_of $port
220 243
221Extracts and returns the node ID from a port ID or a node ID. 244Extracts and returns the node ID from a port ID or a node ID.
222 245
246=item $is_local = port_is_local $port
247
248Returns true iff the port is a local port.
249
223=item configure $profile, key => value... 250=item configure $profile, key => value...
224 251
225=item configure key => value... 252=item configure key => value...
226 253
227Before a node can talk to other nodes on the network (i.e. enter 254Before a node can talk to other nodes on the network (i.e. enter
238=over 4 265=over 4
239 266
240=item norc => $boolean (default false) 267=item norc => $boolean (default false)
241 268
242If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not> 269If true, then the rc file (e.g. F<~/.perl-anyevent-mp>) will I<not>
243be consulted - all configuraiton options must be specified in the 270be consulted - all configuration options must be specified in the
244C<configure> call. 271C<configure> call.
245 272
246=item force => $boolean (default false) 273=item force => $boolean (default false)
247 274
248IF true, then the values specified in the C<configure> will take 275IF true, then the values specified in the C<configure> will take
249precedence over any values configured via the rc file. The default is for 276precedence over any values configured via the rc file. The default is for
250the rc file to override any options specified in the program. 277the rc file to override any options specified in the program.
251
252=item secure => $pass->($nodeid)
253
254In addition to specifying a boolean, you can specify a code reference that
255is called for every remote execution attempt - the execution request is
256granted iff the callback returns a true value.
257
258See F<semp setsecure> for more info.
259 278
260=back 279=back
261 280
262=over 4 281=over 4
263 282
400 419
401sub rcv($@); 420sub rcv($@);
402 421
403my $KILME = sub { 422my $KILME = sub {
404 (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g; 423 (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g;
405 kil $SELF, unhandled_message => "missing (tag or fallback) callback for message '$tag'"; 424 kil $SELF, unhandled_message => "no callback found for message '$tag'";
406}; 425};
407 426
408sub port(;&) { 427sub port(;&) {
409 my $id = $UNIQ . ++$ID; 428 my $id = $UNIQ . ++$ID;
410 my $port = "$NODE#$id"; 429 my $port = "$NODE#$id";
467 486
468sub rcv($@) { 487sub rcv($@) {
469 my $port = shift; 488 my $port = shift;
470 my ($nodeid, $portid) = split /#/, $port, 2; 489 my ($nodeid, $portid) = split /#/, $port, 2;
471 490
472 $NODE{$nodeid} == $NODE{""} 491 $nodeid eq $NODE
473 or Carp::croak "$port: rcv can only be called on local ports, caught"; 492 or Carp::croak "$port: rcv can only be called on local ports, caught";
474 493
475 while (@_) { 494 while (@_) {
476 if (ref $_[0]) { 495 if (ref $_[0]) {
477 if (my $self = $PORT_DATA{$portid}) { 496 if (my $self = $PORT_DATA{$portid}) {
521} 540}
522 541
523=item peval $port, $coderef[, @args] 542=item peval $port, $coderef[, @args]
524 543
525Evaluates the given C<$codref> within the contetx of C<$port>, that is, 544Evaluates the given C<$codref> within the contetx of C<$port>, that is,
526when the code throews an exception the C<$port> will be killed. 545when the code throws an exception the C<$port> will be killed.
527 546
528Any remaining args will be passed to the callback. Any return values will 547Any remaining args will be passed to the callback. Any return values will
529be returned to the caller. 548be returned to the caller.
530 549
531This is useful when you temporarily want to execute code in the context of 550This is useful when you temporarily want to execute code in the context of
596 $res 615 $res
597 } 616 }
598 } 617 }
599} 618}
600 619
620=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
621
622=item $guard = mon $port # kill $SELF when $port dies
623
601=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies 624=item $guard = mon $port, $cb->(@reason) # call $cb when $port dies
602
603=item $guard = mon $port, $rcvport # kill $rcvport when $port dies
604
605=item $guard = mon $port # kill $SELF when $port dies
606 625
607=item $guard = mon $port, $rcvport, @msg # send a message when $port dies 626=item $guard = mon $port, $rcvport, @msg # send a message when $port dies
608 627
609Monitor the given port and do something when the port is killed or 628Monitor the given port and do something when the port is killed or
610messages to it were lost, and optionally return a guard that can be used 629messages to it were lost, and optionally return a guard that can be used
611to stop monitoring again. 630to stop monitoring again.
612 631
632The first two forms distinguish between "normal" and "abnormal" kil's:
633
634In the first form (another port given), if the C<$port> is C<kil>'ed with
635a non-empty reason, the other port (C<$rcvport>) will be kil'ed with the
636same reason. That is, on "normal" kil's nothing happens, while under all
637other conditions, the other port is killed with the same reason.
638
639The second form (kill self) is the same as the first form, except that
640C<$rvport> defaults to C<$SELF>.
641
642The remaining forms don't distinguish between "normal" and "abnormal" kil's
643- it's up to the callback or receiver to check whether the C<@reason> is
644empty and act accordingly.
645
613In the first form (callback), the callback is simply called with any 646In the third form (callback), the callback is simply called with any
614number of C<@reason> elements (no @reason means that the port was deleted 647number of C<@reason> elements (empty @reason means that the port was deleted
615"normally"). Note also that I<< the callback B<must> never die >>, so use 648"normally"). Note also that I<< the callback B<must> never die >>, so use
616C<eval> if unsure. 649C<eval> if unsure.
617 650
618In the second form (another port given), the other port (C<$rcvport>)
619will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
620"normal" kils nothing happens, while under all other conditions, the other
621port is killed with the same reason.
622
623The third form (kill self) is the same as the second form, except that
624C<$rvport> defaults to C<$SELF>.
625
626In the last form (message), a message of the form C<@msg, @reason> will be 651In the last form (message), a message of the form C<$rcvport, @msg,
627C<snd>. 652@reason> will be C<snd>.
628 653
629Monitoring-actions are one-shot: once messages are lost (and a monitoring 654Monitoring-actions are one-shot: once messages are lost (and a monitoring
630alert was raised), they are removed and will not trigger again. 655alert was raised), they are removed and will not trigger again, even if it
656turns out that the port is still alive.
631 657
632As a rule of thumb, monitoring requests should always monitor a port from 658As a rule of thumb, monitoring requests should always monitor a remote
633a local port (or callback). The reason is that kill messages might get 659port locally (using a local C<$rcvport> or a callback). The reason is that
634lost, just like any other message. Another less obvious reason is that 660kill messages might get lost, just like any other message. Another less
635even monitoring requests can get lost (for example, when the connection 661obvious reason is that even monitoring requests can get lost (for example,
636to the other node goes down permanently). When monitoring a port locally 662when the connection to the other node goes down permanently). When
637these problems do not exist. 663monitoring a port locally these problems do not exist.
638 664
639C<mon> effectively guarantees that, in the absence of hardware failures, 665C<mon> effectively guarantees that, in the absence of hardware failures,
640after starting the monitor, either all messages sent to the port will 666after starting the monitor, either all messages sent to the port will
641arrive, or the monitoring action will be invoked after possible message 667arrive, or the monitoring action will be invoked after possible message
642loss has been detected. No messages will be lost "in between" (after 668loss has been detected. No messages will be lost "in between" (after
964If you feel the need to monitor or query a single subkey, try giving it 990If you feel the need to monitor or query a single subkey, try giving it
965it's own family. 991it's own family.
966 992
967=over 993=over
968 994
969=item db_set $family => $subkey [=> $value] 995=item $guard = db_set $family => $subkey [=> $value]
970 996
971Sets (or replaces) a key to the database - if C<$value> is omitted, 997Sets (or replaces) a key to the database - if C<$value> is omitted,
972C<undef> is used instead. 998C<undef> is used instead.
973 999
1000When called in non-void context, C<db_set> returns a guard that
1001automatically calls C<db_del> when it is destroyed.
1002
974=item db_del $family => $subkey... 1003=item db_del $family => $subkey...
975 1004
976Deletes one or more subkeys from the database family. 1005Deletes one or more subkeys from the database family.
977 1006
978=item $guard = db_reg $family => $subkey [=> $value] 1007=item $guard = db_reg $family => $port => $value
979 1008
980Sets the key on the database and returns a guard. When the guard is 1009=item $guard = db_reg $family => $port
981destroyed, the key is deleted from the database. If C<$value> is missing, 1010
982then C<undef> is used. 1011=item $guard = db_reg $family
1012
1013Registers a port in the given family and optionally returns a guard to
1014remove it.
1015
1016This function basically does the same as:
1017
1018 db_set $family => $port => $value
1019
1020Except that the port is monitored and automatically removed from the
1021database family when it is kil'ed.
1022
1023If C<$value> is missing, C<undef> is used. If C<$port> is missing, then
1024C<$SELF> is used.
1025
1026This function is most useful to register a port in some port group (which
1027is just another name for a database family), and have it removed when the
1028port is gone. This works best when the port is a local port.
1029
1030=cut
1031
1032sub db_reg($$;$) {
1033 my $family = shift;
1034 my $port = @_ ? shift : $SELF;
1035
1036 my $clr = sub { db_del $family => $port };
1037 mon $port, $clr;
1038
1039 db_set $family => $port => $_[0];
1040
1041 defined wantarray
1042 and &Guard::guard ($clr)
1043}
983 1044
984=item db_family $family => $cb->(\%familyhash) 1045=item db_family $family => $cb->(\%familyhash)
985 1046
986Queries the named database C<$family> and call the callback with the 1047Queries the named database C<$family> and call the callback with the
987family represented as a hash. You can keep and freely modify the hash. 1048family represented as a hash. You can keep and freely modify the hash.
994=item db_values $family => $cb->(\@values) 1055=item db_values $family => $cb->(\@values)
995 1056
996Same as C<db_family>, except it only queries the family I<values> and passes them 1057Same as C<db_family>, except it only queries the family I<values> and passes them
997as array reference to the callback. 1058as array reference to the callback.
998 1059
999=item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted) 1060=item $guard = db_mon $family => $cb->(\%familyhash, \@added, \@changed, \@deleted)
1000 1061
1001Creates a monitor on the given database family. Each time a key is set 1062Creates a monitor on the given database family. Each time a key is set
1002or or is deleted the callback is called with a hash containing the 1063or or is deleted the callback is called with a hash containing the
1003database family and three lists of added, changed and deleted subkeys, 1064database family and three lists of added, changed and deleted subkeys,
1004respectively. If no keys have changed then the array reference might be 1065respectively. If no keys have changed then the array reference might be
1212Keeping your messages simple, concentrating on data structures rather than 1273Keeping your messages simple, concentrating on data structures rather than
1213objects, will keep your messages clean, tidy and efficient. 1274objects, will keep your messages clean, tidy and efficient.
1214 1275
1215=back 1276=back
1216 1277
1278=head1 PORTING FROM AnyEvent::MP VERSION 1.X
1279
1280AEMP version 2 has a few major incompatible changes compared to version 1:
1281
1282=over 4
1283
1284=item AnyEvent::MP::Global no longer has group management functions.
1285
1286At least not officially - the grp_* functions are still exported and might
1287work, but they will be removed in some later release.
1288
1289AnyEvent::MP now comes with a distributed database that is more
1290powerful. Its database families map closely to port groups, but the API
1291has changed (the functions are also now exported by AnyEvent::MP). Here is
1292a rough porting guide:
1293
1294 grp_reg $group, $port # old
1295 db_reg $group, $port # new
1296
1297 $list = grp_get $group # old
1298 db_keys $group, sub { my $list = shift } # new
1299
1300 grp_mon $group, $cb->(\@ports, $add, $del) # old
1301 db_mon $group, $cb->(\%ports, $add, $change, $del) # new
1302
1303C<grp_reg> is a no-brainer (just replace by C<db_reg>), but C<grp_get> is
1304no longer instant, because the local node might not have a copy of the
1305group. You can either modify your code to allow for a callback, or use
1306C<db_mon> to keep an updated copy of the group:
1307
1308 my $local_group_copy;
1309 db_mon $group => sub { $local_group_copy = $_[0] };
1310
1311 # now "keys %$local_group_copy" always returns the most up-to-date
1312 # list of ports in the group.
1313
1314C<grp_mon> can be replaced by C<db_mon> with minor changes - C<db_mon>
1315passes a hash as first argument, and an extra C<$chg> argument that can be
1316ignored:
1317
1318 db_mon $group => sub {
1319 my ($ports, $add, $chg, $lde) = @_;
1320 $ports = [keys %$ports];
1321
1322 # now $ports, $add and $del are the same as
1323 # were originally passed by grp_mon.
1324 ...
1325 };
1326
1327=item Nodes not longer connect to all other nodes.
1328
1329In AEMP 1.x, every node automatically loads the L<AnyEvent::MP::Global>
1330module, which in turn would create connections to all other nodes in the
1331network (helped by the seed nodes).
1332
1333In version 2.x, global nodes still connect to all other global nodes, but
1334other nodes don't - now every node either is a global node itself, or
1335attaches itself to another global node.
1336
1337If a node isn't a global node itself, then it attaches itself to one
1338of its seed nodes. If that seed node isn't a global node yet, it will
1339automatically be upgraded to a global node.
1340
1341So in many cases, nothing needs to be changed - one just has to make sure
1342that all seed nodes are meshed together with the other seed nodes (as with
1343AEMP 1.x), and other nodes specify them as seed nodes. This is most easily
1344achieved by specifying the same set of seed nodes for all nodes in the
1345network.
1346
1347Not opening a connection to every other node is usually an advantage,
1348except when you need the lower latency of an already established
1349connection. To ensure a node establishes a connection to another node,
1350you can monitor the node port (C<mon $node, ...>), which will attempt to
1351create the connection (and notify you when the connection fails).
1352
1353=item Listener-less nodes (nodes without binds) are gone.
1354
1355And are not coming back, at least not in their old form. If no C<binds>
1356are specified for a node, AnyEvent::MP assumes a default of C<*:*>.
1357
1358There are vague plans to implement some form of routing domains, which
1359might or might not bring back listener-less nodes, but don't count on it.
1360
1361The fact that most connections are now optional somewhat mitigates this,
1362as a node can be effectively unreachable from the outside without any
1363problems, as long as it isn't a global node and only reaches out to other
1364nodes (as opposed to being contacted from other nodes).
1365
1366=item $AnyEvent::MP::Kernel::WARN has gone.
1367
1368AnyEvent has acquired a logging framework (L<AnyEvent::Log>), and AEMP now
1369uses this, and so should your programs.
1370
1371Every module now documents what kinds of messages it generates, with
1372AnyEvent::MP acting as a catch all.
1373
1374On the positive side, this means that instead of setting
1375C<PERL_ANYEVENT_MP_WARNLEVEL>, you can get away by setting C<AE_VERBOSE> -
1376much less to type.
1377
1378=back
1379
1380=head1 LOGGING
1381
1382AnyEvent::MP does not normally log anything by itself, but sinc eit is the
1383root of the contetx hierarchy for AnyEvent::MP modules, it will receive
1384all log messages by submodules.
1385
1217=head1 SEE ALSO 1386=head1 SEE ALSO
1218 1387
1219L<AnyEvent::MP::Intro> - a gentle introduction. 1388L<AnyEvent::MP::Intro> - a gentle introduction.
1220 1389
1221L<AnyEvent::MP::Kernel> - more, lower-level, stuff. 1390L<AnyEvent::MP::Kernel> - more, lower-level, stuff.

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