Unverified Commit 100c1501 authored by emilylange's avatar emilylange
Browse files

nixos/loki: skip config validation when it's impossible to validate 

This is a follow-up to 8d7f3c9d and
ae48735c.

Running the config validation in the build sandbox is impossible and
will fail when using `cfg.configFile` or `-config.expand-env=true`.

`cfg.configFile` is a string of a path which is simply not available to
the build sandbox.

Similarly, one may opt to use `cfg.configuration` with environment
variables in combination with `-config.expand-env=true`.

The environment variables referenced that way are also not available
in the build sandbox.

So we skip the validation when it's impossible (`cfg.configFile`) or
likely impossible (`-config.expand-env=true`).

An alternative approach would be something like nixos/prometheus'
`services.prometheus.checkConfig` that takes a boolean and makes
toggling the config validation user-facing.
parent 68ead292

nixos/modules/services/monitoring/loki.nix

+7 −2
Original line number Diff line number Diff line
@@ -97,7 +97,12 @@ in { 


      serviceConfig = let

        conf = if cfg.configFile == null

               then prettyJSON cfg.configuration

               then

                 # Config validation may fail when using extraFlags = [ "-config.expand-env=true" ].

                 # To work around this, we simply skip it when extraFlags is not empty.

                 if cfg.extraFlags == []

                 then validateConfig (prettyJSON cfg.configuration)

                 else prettyJSON cfg.configuration

               else cfg.configFile;

        validateConfig = file:

        pkgs.runCommand "validate-loki-conf" {
@@ -108,7 +113,7 @@ in { 
          '';

      in

      {

        ExecStart = "${cfg.package}/bin/loki --config.file=${validateConfig conf} ${escapeShellArgs cfg.extraFlags}";

        ExecStart = "${cfg.package}/bin/loki --config.file=${conf} ${escapeShellArgs cfg.extraFlags}";

        User = cfg.user;

        Restart = "always";

        PrivateTmp = true;