… | |
… | |
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 $SELF port context |
… | |
… | |
398 | |
398 | |
399 | =cut |
399 | =cut |
400 | |
400 | |
401 | sub rcv($@); |
401 | sub rcv($@); |
402 | |
402 | |
403 | sub _kilme { |
403 | my $KILME = sub { |
404 | die "received message on port without callback"; |
404 | (my $tag = substr $_[0], 0, 30) =~ s/([\x20-\x7e])/./g; |
405 | } |
405 | kil $SELF, unhandled_message => "no callback set for message (first element $tag)"; |
|
|
406 | }; |
406 | |
407 | |
407 | sub port(;&) { |
408 | sub port(;&) { |
408 | my $id = $UNIQ . ++$ID; |
409 | my $id = $UNIQ . ++$ID; |
409 | my $port = "$NODE#$id"; |
410 | my $port = "$NODE#$id"; |
410 | |
411 | |
411 | rcv $port, shift || \&_kilme; |
412 | rcv $port, shift || $KILME; |
412 | |
413 | |
413 | $port |
414 | $port |
414 | } |
415 | } |
415 | |
416 | |
416 | =item rcv $local_port, $callback->(@msg) |
417 | =item rcv $local_port, $callback->(@msg) |
… | |
… | |
421 | |
422 | |
422 | The global C<$SELF> (exported by this module) contains C<$port> while |
423 | The global C<$SELF> (exported by this module) contains C<$port> while |
423 | executing the callback. Runtime errors during callback execution will |
424 | executing the callback. Runtime errors during callback execution will |
424 | result in the port being C<kil>ed. |
425 | result in the port being C<kil>ed. |
425 | |
426 | |
426 | The default callback received all messages not matched by a more specific |
427 | The default callback receives all messages not matched by a more specific |
427 | C<tag> match. |
428 | C<tag> match. |
428 | |
429 | |
429 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
430 | =item rcv $local_port, tag => $callback->(@msg_without_tag), ... |
430 | |
431 | |
431 | Register (or replace) callbacks to be called on messages starting with the |
432 | Register (or replace) callbacks to be called on messages starting with the |
… | |
… | |
732 | will be reported as reason C<< die => $@ >>. |
733 | will be reported as reason C<< die => $@ >>. |
733 | |
734 | |
734 | Transport/communication errors are reported as C<< transport_error => |
735 | Transport/communication errors are reported as C<< transport_error => |
735 | $message >>. |
736 | $message >>. |
736 | |
737 | |
737 | =cut |
738 | Common idioms: |
|
|
739 | |
|
|
740 | # silently remove yourself, do not kill linked ports |
|
|
741 | kil $SELF; |
|
|
742 | |
|
|
743 | # report a failure in some detail |
|
|
744 | kil $SELF, failure_mode_1 => "it failed with too high temperature"; |
|
|
745 | |
|
|
746 | # do not waste much time with killing, just die when something goes wrong |
|
|
747 | open my $fh, "<file" |
|
|
748 | or die "file: $!"; |
738 | |
749 | |
739 | =item $port = spawn $node, $initfunc[, @initdata] |
750 | =item $port = spawn $node, $initfunc[, @initdata] |
740 | |
751 | |
741 | Creates a port on the node C<$node> (which can also be a port ID, in which |
752 | Creates a port on the node C<$node> (which can also be a port ID, in which |
742 | case it's the node where that port resides). |
753 | case it's the node where that port resides). |
… | |
… | |
834 | ref $action[0] |
845 | ref $action[0] |
835 | ? $action[0]() |
846 | ? $action[0]() |
836 | : snd @action; |
847 | : snd @action; |
837 | }; |
848 | }; |
838 | } |
849 | } |
|
|
850 | |
|
|
851 | #=item $cb2 = timeout $seconds, $cb[, @args] |
839 | |
852 | |
840 | =item cal $port, @msg, $callback[, $timeout] |
853 | =item cal $port, @msg, $callback[, $timeout] |
841 | |
854 | |
842 | A simple form of RPC - sends a message to the given C<$port> with the |
855 | A simple form of RPC - sends a message to the given C<$port> with the |
843 | given contents (C<@msg>), but adds a reply port to the message. |
856 | given contents (C<@msg>), but adds a reply port to the message. |
… | |
… | |
892 | =back |
905 | =back |
893 | |
906 | |
894 | =head1 DISTRIBUTED DATABASE |
907 | =head1 DISTRIBUTED DATABASE |
895 | |
908 | |
896 | AnyEvent::MP comes with a simple distributed database. The database will |
909 | AnyEvent::MP comes with a simple distributed database. The database will |
897 | be mirrored asynchronously at all global nodes. Other nodes bind to one of |
910 | be mirrored asynchronously on all global nodes. Other nodes bind to one |
898 | the global nodes for their needs. |
911 | of the global nodes for their needs. Every node has a "local database" |
|
|
912 | which contains all the values that are set locally. All local databases |
|
|
913 | are merged together to form the global database, which can be queried. |
899 | |
914 | |
900 | The database consists of a two-level hash - a hash contains a hash which |
915 | The database structure is that of a two-level hash - the database hash |
901 | contains values. |
916 | contains hashes which contain values, similarly to a perl hash of hashes, |
|
|
917 | i.e.: |
|
|
918 | |
|
|
919 | $DATABASE{$family}{$subkey} = $value |
902 | |
920 | |
903 | The top level hash key is called "family", and the second-level hash key |
921 | The top level hash key is called "family", and the second-level hash key |
904 | is called "subkey" or simply "key". |
922 | is called "subkey" or simply "key". |
905 | |
923 | |
906 | The family must be alphanumeric, i.e. start with a letter and consist |
924 | The family must be alphanumeric, i.e. start with a letter and consist |
… | |
… | |
911 | with the name of the application or module using it. |
929 | with the name of the application or module using it. |
912 | |
930 | |
913 | The subkeys must be non-empty strings, with no further restrictions. |
931 | The subkeys must be non-empty strings, with no further restrictions. |
914 | |
932 | |
915 | The values should preferably be strings, but other perl scalars should |
933 | The values should preferably be strings, but other perl scalars should |
916 | work as well (such as undef, arrays and hashes). |
934 | work as well (such as C<undef>, arrays and hashes). |
917 | |
935 | |
918 | Every database entry is owned by one node - adding the same family/subkey |
936 | Every database entry is owned by one node - adding the same family/subkey |
919 | combination on multiple nodes will not cause discomfort for AnyEvent::MP, |
937 | combination on multiple nodes will not cause discomfort for AnyEvent::MP, |
920 | but the result might be nondeterministic, i.e. the key might have |
938 | but the result might be nondeterministic, i.e. the key might have |
921 | different values on different nodes. |
939 | different values on different nodes. |
… | |
… | |
925 | pools. For example, a worker port for image scaling might do this: |
943 | pools. For example, a worker port for image scaling might do this: |
926 | |
944 | |
927 | db_set my_image_scalers => $port; |
945 | db_set my_image_scalers => $port; |
928 | |
946 | |
929 | And clients looking for an image scaler will want to get the |
947 | And clients looking for an image scaler will want to get the |
930 | C<my_image_scalers> keys: |
948 | C<my_image_scalers> keys from time to time: |
931 | |
949 | |
932 | db_keys "my_image_scalers" => 60 => sub { |
950 | db_keys my_image_scalers => sub { |
933 | #d##TODO# |
951 | @ports = @{ $_[0] }; |
|
|
952 | }; |
|
|
953 | |
|
|
954 | Or better yet, they want to monitor the database family, so they always |
|
|
955 | have a reasonable up-to-date copy: |
|
|
956 | |
|
|
957 | db_mon my_image_scalers => sub { |
|
|
958 | @ports = keys %{ $_[0] }; |
|
|
959 | }; |
|
|
960 | |
|
|
961 | In general, you can set or delete single subkeys, but query and monitor |
|
|
962 | whole families only. |
|
|
963 | |
|
|
964 | If you feel the need to monitor or query a single subkey, try giving it |
|
|
965 | it's own family. |
934 | |
966 | |
935 | =over |
967 | =over |
936 | |
968 | |
937 | =item db_set $family => $subkey [=> $value] |
969 | =item db_set $family => $subkey [=> $value] |
938 | |
970 | |
939 | Sets (or replaces) a key to the database - if C<$value> is omitted, |
971 | Sets (or replaces) a key to the database - if C<$value> is omitted, |
940 | C<undef> is used instead. |
972 | C<undef> is used instead. |
941 | |
973 | |
942 | =item db_del $family => $subkey |
974 | =item db_del $family => $subkey... |
943 | |
975 | |
944 | Deletes a key from the database. |
976 | Deletes one or more subkeys from the database family. |
945 | |
977 | |
946 | =item $guard = db_reg $family => $subkey [=> $value] |
978 | =item $guard = db_reg $family => $subkey [=> $value] |
947 | |
979 | |
948 | Sets the key on the database and returns a guard. When the guard is |
980 | Sets the key on the database and returns a guard. When the guard is |
949 | destroyed, the key is deleted from the database. If C<$value> is missing, |
981 | destroyed, the key is deleted from the database. If C<$value> is missing, |
950 | then C<undef> is used. |
982 | then C<undef> is used. |
951 | |
983 | |
|
|
984 | =item db_family $family => $cb->(\%familyhash) |
|
|
985 | |
|
|
986 | Queries the named database C<$family> and call the callback with the |
|
|
987 | family represented as a hash. You can keep and freely modify the hash. |
|
|
988 | |
|
|
989 | =item db_keys $family => $cb->(\@keys) |
|
|
990 | |
|
|
991 | Same as C<db_family>, except it only queries the family I<subkeys> and passes |
|
|
992 | them as array reference to the callback. |
|
|
993 | |
|
|
994 | =item db_values $family => $cb->(\@values) |
|
|
995 | |
|
|
996 | Same as C<db_family>, except it only queries the family I<values> and passes them |
|
|
997 | as array reference to the callback. |
|
|
998 | |
952 | =item $guard = db_mon $family => $cb->($familyhash, \@subkeys...) |
999 | =item $guard = db_mon $family => $cb->($familyhash, \@added, \@changed, \@deleted) |
953 | |
1000 | |
954 | Creates a monitor on the given database family. Each time a key is set or |
1001 | Creates a monitor on the given database family. Each time a key is set |
955 | or is deleted the callback is called with a hash containing the database |
1002 | or or is deleted the callback is called with a hash containing the |
956 | family and an arrayref with subkeys that have changed. |
1003 | database family and three lists of added, changed and deleted subkeys, |
|
|
1004 | respectively. If no keys have changed then the array reference might be |
|
|
1005 | C<undef> or even missing. |
957 | |
1006 | |
958 | Specifically, if one of the passed subkeys exists in the $familyhash, then |
1007 | If not called in void context, a guard object is returned that, when |
959 | it is currently set to the value in the $familyhash. Otherwise, it has |
1008 | destroyed, stops the monitor. |
960 | been deleted. |
|
|
961 | |
1009 | |
962 | The first call will be with the current contents of the family and all |
1010 | The family hash reference and the key arrays belong to AnyEvent::MP and |
963 | keys, as if they were just added. |
1011 | B<must not be modified or stored> by the callback. When in doubt, make a |
|
|
1012 | copy. |
|
|
1013 | |
|
|
1014 | As soon as possible after the monitoring starts, the callback will be |
|
|
1015 | called with the intiial contents of the family, even if it is empty, |
|
|
1016 | i.e. there will always be a timely call to the callback with the current |
|
|
1017 | contents. |
964 | |
1018 | |
965 | It is possible that the callback is called with a change event even though |
1019 | It is possible that the callback is called with a change event even though |
966 | the subkey is already present and the value has not changed. |
1020 | the subkey is already present and the value has not changed. |
967 | |
1021 | |
968 | The monitoring stops when the guard object is destroyed. |
1022 | The monitoring stops when the guard object is destroyed. |
969 | |
1023 | |
970 | Example: on every change to the family "mygroup", print out all keys. |
1024 | Example: on every change to the family "mygroup", print out all keys. |
971 | |
1025 | |
972 | my $guard = db_mon mygroup => sub { |
1026 | my $guard = db_mon mygroup => sub { |
973 | my ($family, $keys) = @_; |
1027 | my ($family, $a, $c, $d) = @_; |
974 | print "mygroup members: ", (join " ", keys %$family), "\n"; |
1028 | print "mygroup members: ", (join " ", keys %$family), "\n"; |
975 | }; |
1029 | }; |
976 | |
1030 | |
977 | Exmaple: wait until the family "My::Module::workers" is non-empty. |
1031 | Exmaple: wait until the family "My::Module::workers" is non-empty. |
978 | |
1032 | |
979 | my $guard; $guard = db_mon My::Module::workers => sub { |
1033 | my $guard; $guard = db_mon My::Module::workers => sub { |
980 | my ($family, $keys) = @_; |
1034 | my ($family, $a, $c, $d) = @_; |
981 | return unless %$family; |
1035 | return unless %$family; |
982 | undef $guard; |
1036 | undef $guard; |
983 | print "My::Module::workers now nonempty\n"; |
1037 | print "My::Module::workers now nonempty\n"; |
984 | }; |
1038 | }; |
985 | |
1039 | |
986 | Example: print all changes to the family "AnyRvent::Fantasy::Module". |
1040 | Example: print all changes to the family "AnyRvent::Fantasy::Module". |
987 | |
1041 | |
988 | my $guard = db_mon AnyRvent::Fantasy::Module => sub { |
1042 | my $guard = db_mon AnyRvent::Fantasy::Module => sub { |
989 | my ($family, $keys) = @_; |
1043 | my ($family, $a, $c, $d) = @_; |
990 | |
1044 | |
991 | for (@$keys) { |
1045 | print "+$_=$family->{$_}\n" for @$a; |
992 | print "$_: ", |
1046 | print "*$_=$family->{$_}\n" for @$c; |
993 | (exists $family->{$_} |
1047 | print "-$_=$family->{$_}\n" for @$d; |
994 | ? $family->{$_} |
|
|
995 | : "(deleted)"), |
|
|
996 | "\n"; |
|
|
997 | } |
|
|
998 | }; |
1048 | }; |
999 | |
1049 | |
1000 | =cut |
1050 | =cut |
1001 | |
1051 | |
1002 | =back |
1052 | =back |