nixos/prometheus/exporters/knot: init

nixos/modules/services/monitoring/prometheus/exporters.nix

@@ -31,6 +31,7 @@ let
     "fritzbox"
     "json"
     "keylight"
+    "knot"
     "lnd"
     "mail"
     "mikrotik"

nixos/modules/services/monitoring/prometheus/exporters/knot.nix

@@ -0,0 +1,50 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.knot;
+in {
+  port = 9433;
+  extraOpts = {
+    knotLibraryPath = mkOption {
+      type = types.str;
+      default = "${pkgs.knot-dns.out}/lib/libknot.so";
+      defaultText = "\${pkgs.knot-dns}/lib/libknot.so";
+      description = ''
+        Path to the library of <package>knot-dns</package>.
+      '';
+    };
+
+    knotSocketPath = mkOption {
+      type = types.str;
+      default = "/run/knot/knot.sock";
+      description = ''
+        Socket path of <citerefentry><refentrytitle>knotd</refentrytitle>
+        <manvolnum>8</manvolnum></citerefentry>.
+      '';
+    };
+
+    knotSocketTimeout = mkOption {
+      type = types.int;
+      default = 2000;
+      description = ''
+        Timeout in seconds.
+      '';
+    };
+  };
+  serviceOpts = {
+    serviceConfig = {
+      ExecStart = ''
+        ${pkgs.prometheus-knot-exporter}/bin/knot_exporter \
+          --web-listen-addr ${cfg.listenAddress} \
+          --web-listen-port ${toString cfg.port} \
+          --knot-library-path ${cfg.knotLibraryPath} \
+          --knot-socket-path ${cfg.knotSocketPath} \
+          --knot-socket-timeout ${toString cfg.knotSocketTimeout} \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+      SupplementaryGroups = [ "knot" ];
+    };
+  };
+}

nixos/tests/prometheus-exporters.nix

@@ -248,6 +248,24 @@ let
       '';
     };
 
+    knot = {
+      exporterConfig = {
+        enable = true;
+      };
+      metricProvider = {
+        services.knot = {
+          enable = true;
+          extraArgs = [ "-v" ];
+        };
+      };
+      exporterTest = ''
+        wait_for_unit("knot.service")
+        wait_for_unit("prometheus-knot-exporter.service")
+        wait_for_open_port(9433)
+        succeed("curl -sSf 'localhost:9433' | grep -q 'knot_server_zone_count 0.0'")
+      '';
+    };
+
     keylight = {
       # A hardware device is required to properly test this exporter, so just
       # perform a couple of basic sanity checks that the exporter is running