… | |
… | |
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 |
… | |
… | |
197 | NODE $NODE *SELF node_of after |
197 | NODE $NODE *SELF node_of after |
198 | configure |
198 | configure |
199 | snd rcv mon mon_guard kil psub peval spawn cal |
199 | snd rcv mon mon_guard kil psub peval spawn cal |
200 | port |
200 | port |
201 | db_set db_del db_reg |
201 | db_set db_del db_reg |
|
|
202 | db_mon db_family db_keys db_values |
202 | ); |
203 | ); |
203 | |
204 | |
204 | our $SELF; |
205 | our $SELF; |
205 | |
206 | |
206 | sub _self_die() { |
207 | sub _self_die() { |
… | |
… | |
230 | |
231 | |
231 | 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 |
232 | never) before calling other AnyEvent::MP functions. |
233 | never) before calling other AnyEvent::MP functions. |
233 | |
234 | |
234 | 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 |
235 | 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: |
236 | |
237 | |
237 | =over 4 |
238 | =over 4 |
238 | |
239 | |
239 | =item norc => $boolean (default false) |
240 | =item norc => $boolean (default false) |
240 | |
241 | |
… | |
… | |
245 | =item force => $boolean (default false) |
246 | =item force => $boolean (default false) |
246 | |
247 | |
247 | 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 |
248 | 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 |
249 | 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 => $pass->(@msg) |
|
|
253 | |
|
|
254 | In addition to specifying a boolean, you can specify a code reference that |
|
|
255 | is called for every code execution attempt - the execution request is |
|
|
256 | granted iff the callback returns a true value. |
|
|
257 | |
|
|
258 | Most of the time the callback should look only at |
|
|
259 | C<$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. |
250 | |
264 | |
251 | =back |
265 | =back |
252 | |
266 | |
253 | =over 4 |
267 | =over 4 |
254 | |
268 | |
… | |
… | |
271 | and the values specified directly via C<configure> have lowest priority, |
285 | and the values specified directly via C<configure> have lowest priority, |
272 | and can only be used to specify defaults. |
286 | and can only be used to specify defaults. |
273 | |
287 | |
274 | 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 |
275 | this process. If not, then the profile name will be used as node ID, with |
289 | this process. If not, then the profile name will be used as node ID, with |
276 | a slash (C</>) attached. |
290 | a unique randoms tring (C</%u>) appended. |
277 | |
291 | |
278 | If the node ID (or profile name) ends with a slash (C</>), then a random |
292 | The node ID can contain some C<%> sequences that are expanded: C<%n> |
279 | string is appended to make it unique. |
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>. |
280 | |
297 | |
281 | =item step 2, bind listener sockets |
298 | =item step 2, bind listener sockets |
282 | |
299 | |
283 | 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 |
284 | 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 |
… | |
… | |
301 | 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. |
302 | 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. |
303 | |
320 | |
304 | configure |
321 | configure |
305 | |
322 | |
306 | 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 |
307 | clients. |
324 | commandline clients. |
308 | |
325 | |
309 | configure nodeid => "anon/"; |
326 | configure nodeid => "myscript/%n/%u"; |
310 | |
327 | |
311 | 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 |
312 | 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, |
313 | customary for aemp). |
330 | customary for aemp). |
314 | |
331 | |
… | |
… | |
386 | |
403 | |
387 | =cut |
404 | =cut |
388 | |
405 | |
389 | sub rcv($@); |
406 | sub rcv($@); |
390 | |
407 | |
391 | sub _kilme { |
408 | my $KILME = sub { |
392 | die "received message on port without callback"; |
409 | (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g; |
393 | } |
410 | kil $SELF, unhandled_message => "no callback found for message '$tag'"; |
|
|
411 | }; |
394 | |
412 | |
395 | sub port(;&) { |
413 | sub port(;&) { |
396 | my $id = $UNIQ . ++$ID; |
414 | my $id = $UNIQ . ++$ID; |
397 | my $port = "$NODE#$id"; |
415 | my $port = "$NODE#$id"; |
398 | |
416 | |
399 | rcv $port, shift || \&_kilme; |
417 | rcv $port, shift || $KILME; |
400 | |
418 | |
401 | $port |
419 | $port |
402 | } |
420 | } |
403 | |
421 | |
404 | =item rcv $local_port, $callback->(@msg) |
422 | =item rcv $local_port, $callback->(@msg) |
… | |
… | |
409 | |
427 | |
410 | The global C<$SELF> (exported by this module) contains C<$port> while |
428 | The global C<$SELF> (exported by this module) contains C<$port> while |
411 | executing the callback. Runtime errors during callback execution will |
429 | executing the callback. Runtime errors during callback execution will |
412 | result in the port being C<kil>ed. |
430 | result in the port being C<kil>ed. |
413 | |
431 | |
414 | 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 |
415 | C<tag> match. |
433 | C<tag> match. |
416 | |
434 | |
417 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
435 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
418 | |
436 | |
419 | 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 |
… | |
… | |
720 | will be reported as reason C<< die => $@ >>. |
738 | will be reported as reason C<< die => $@ >>. |
721 | |
739 | |
722 | Transport/communication errors are reported as C<< transport_error => |
740 | Transport/communication errors are reported as C<< transport_error => |
723 | $message >>. |
741 | $message >>. |
724 | |
742 | |
725 | =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: $!"; |
726 | |
754 | |
727 | =item $port = spawn $node, $initfunc[, @initdata] |
755 | =item $port = spawn $node, $initfunc[, @initdata] |
728 | |
756 | |
729 | Creates a port on the node C<$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 |
730 | case it's the node where that port resides). |
758 | case it's the node where that port resides). |
… | |
… | |
822 | ref $action[0] |
850 | ref $action[0] |
823 | ? $action[0]() |
851 | ? $action[0]() |
824 | : snd @action; |
852 | : snd @action; |
825 | }; |
853 | }; |
826 | } |
854 | } |
|
|
855 | |
|
|
856 | #=item $cb2 = timeout $seconds, $cb[, @args] |
827 | |
857 | |
828 | =item cal $port, @msg, $callback[, $timeout] |
858 | =item cal $port, @msg, $callback[, $timeout] |
829 | |
859 | |
830 | A simple form of RPC - sends a message to the given C<$port> with the |
860 | A simple form of RPC - sends a message to the given C<$port> with the |
831 | 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. |
… | |
… | |
880 | =back |
910 | =back |
881 | |
911 | |
882 | =head1 DISTRIBUTED DATABASE |
912 | =head1 DISTRIBUTED DATABASE |
883 | |
913 | |
884 | AnyEvent::MP comes with a simple distributed database. The database will |
914 | AnyEvent::MP comes with a simple distributed database. The database will |
885 | be mirrored asynchronously at all global nodes. Other nodes bind to one of |
915 | be mirrored asynchronously on all global nodes. Other nodes bind to one |
886 | the global nodes for their needs. |
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. |
887 | |
919 | |
888 | The database consists of a two-level hash - a hash contains a hash which |
920 | The database structure is that of a two-level hash - the database hash |
889 | contains values. |
921 | contains hashes which contain values, similarly to a perl hash of hashes, |
|
|
922 | i.e.: |
|
|
923 | |
|
|
924 | $DATABASE{$family}{$subkey} = $value |
890 | |
925 | |
891 | The top level hash key is called "family", and the second-level hash key |
926 | The top level hash key is called "family", and the second-level hash key |
892 | is simply called "key". |
927 | is called "subkey" or simply "key". |
893 | |
928 | |
894 | The family and key must be alphanumeric ASCII strings, i.e. start |
929 | The family must be alphanumeric, i.e. start with a letter and consist |
895 | with a letter and consist of letters, digits, underscores and colons |
930 | of letters, digits, underscores and colons (C<[A-Za-z][A-Za-z0-9_:]*>, |
896 | (C<[A-Za-z][A-Za-z0-9_:]*>, pretty much like Perl module names. |
931 | pretty much like Perl module names. |
897 | |
932 | |
898 | As the family namespaceis global, it is recommended to prefix family names |
933 | As the family namespace is global, it is recommended to prefix family names |
899 | with the name of the application or module using it. |
934 | with the name of the application or module using it. |
900 | |
935 | |
|
|
936 | The subkeys must be non-empty strings, with no further restrictions. |
|
|
937 | |
901 | The values should preferably be strings, but other perl scalars should |
938 | The values should preferably be strings, but other perl scalars should |
902 | work as well (such as arrays and hashes). |
939 | work as well (such as C<undef>, arrays and hashes). |
903 | |
940 | |
904 | Every database entry is owned by one node - adding the same family/key |
941 | Every database entry is owned by one node - adding the same family/subkey |
905 | combination on multiple nodes will not cause discomfort for AnyEvent::MP, |
942 | combination on multiple nodes will not cause discomfort for AnyEvent::MP, |
906 | but the result might be nondeterministic, i.e. the key might have |
943 | but the result might be nondeterministic, i.e. the key might have |
907 | different values on different nodes. |
944 | different values on different nodes. |
908 | |
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 | |
909 | =item db_set $family => $key => $value |
974 | =item db_set $family => $subkey [=> $value] |
910 | |
975 | |
911 | Sets (or replaces) a key to the database. |
976 | Sets (or replaces) a key to the database - if C<$value> is omitted, |
|
|
977 | C<undef> is used instead. |
912 | |
978 | |
913 | =item db_del $family => $key |
979 | =item db_del $family => $subkey... |
914 | |
980 | |
915 | Deletes a key from the database. |
981 | Deletes one or more subkeys from the database family. |
916 | |
982 | |
917 | =item $guard = db_reg $family => $key [=> $value] |
983 | =item $guard = db_reg $family => $subkey [=> $value] |
918 | |
984 | |
919 | Sets the key on the database and returns a guard. When the guard is |
985 | Sets the key on the database and returns a guard. When the guard is |
920 | destroyed, the key is deleted from the database. If C<$value> is missing, |
986 | destroyed, the key is deleted from the database. If C<$value> is missing, |
921 | then C<undef> is used. |
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 | }; |
922 | |
1054 | |
923 | =cut |
1055 | =cut |
924 | |
1056 | |
925 | =back |
1057 | =back |
926 | |
1058 | |