liminix

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subscriber.nix (1398B)

      1 {
      2   liminix,
      3   lib,
      4   lim,
      5   s6,
      6   s6-rc,
      7   watch-outputs,
      8   s6-rc-up-tree
      9 }:
     10 {
     11   watch,
     12   service,
     13   action,
     14 }:
     15 let
     16   inherit (liminix.services) oneshot longrun;
     17   inherit (builtins) map length head toString;
     18   inherit (lib) unique optional optionals concatStringsSep;
     19   inherit (service) name;
     20 
     21   watched-services = unique (map (f: f "service") watch);
     22 
     23   restart-flag =
     24     {
     25       restart = "-r";
     26       restart-all = "-R";
     27       "hup" = "-s 1";
     28       "int" = "-s 2";
     29       "quit" = "-s 3";
     30       "kill" = "-s 9";
     31       "term" = "-s 15";
     32       "winch" = "-s 20";
     33       "usr1" = "-s usr1";
     34       "usr2" = "-s usr2";
     35     }
     36     .${action};
     37 
     38   watcher =
     39     let
     40       name' = "restart-${name}";
     41       refs = concatStringsSep " "
     42         (map (s: "${s "service"}:${s "path"}") watch);
     43     in
     44     longrun {
     45       name = name';
     46       run = ''
     47         dir=/run/service/${name}
     48         echo waiting for $dir
     49         if test -e $dir/notification-fd; then flag="-U"; else flag="-u"; fi
     50         ${s6}/bin/s6-svwait $flag /run/service/${name} || exit
     51         PATH=${s6-rc}/bin:${s6}/bin:${s6-rc-up-tree}/bin:$PATH
     52         ${watch-outputs}/bin/watch-outputs ${restart-flag} ${name} ${refs}
     53       '';
     54     };
     55 in
     56 service.overrideAttrs (o: {
     57   buildInputs = (lim.orEmpty o.buildInputs) ++ optional (watch != []) watcher;
     58   dependencies =
     59     (lim.orEmpty o.dependencies)
     60     ++ optional (watch != []) watcher;
     61 })