nixos/gs1200-exporter: init module

nixos/modules/module-list.nix

@@ -1030,6 +1030,7 @@
   ./services/monitoring/grafana-to-ntfy.nix
   ./services/monitoring/grafana.nix
   ./services/monitoring/graphite.nix
+  ./services/monitoring/gs1200-exporter.nix
   ./services/monitoring/hdaps.nix
   ./services/monitoring/heapster.nix
   ./services/monitoring/incron.nix

nixos/modules/services/monitoring/gs1200-exporter.nix

@@ -0,0 +1,95 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.services.gs1200-exporter;
+in
+{
+  meta.maintainers = with lib.maintainers; [ DerGrumpf ];
+
+  options.services.gs1200-exporter = {
+    enable = lib.mkEnableOption "gs1200-exporter";
+
+    address = lib.mkOption {
+      type = lib.types.str;
+      description = "IP address or hostname of the GS1200 switch.";
+      example = "192.168.1.3";
+    };
+
+    port = lib.mkOption {
+      type = lib.types.port;
+      default = 9934;
+      description = "Port on which to expose Prometheus metrics.";
+    };
+
+    passwordFile = lib.mkOption {
+      type = lib.types.nullOr lib.types.path;
+      default = null;
+      description = ''
+        Path to a file containing the password to log in to the GS1200 web interface.
+        This is the recommended option as it avoids storing the password in the Nix store.
+        Compatible with sops-nix and agenix.
+      '';
+      example = "/run/secrets/gs1200-password";
+    };
+
+    debug = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = "Enable debug logging. Logs are accessible via journalctl -u gs1200-exporter.";
+    };
+
+    verbose = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = "Enable verbose logging. Logs are accessible via journalctl -u gs1200-exporter.";
+    };
+
+    json = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = "Output logs in JSON format. Logs are accessible via journalctl -u gs1200-exporter.";
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+
+    systemd.services.gs1200-exporter = {
+      description = "Prometheus exporter for Zyxel GS1200 switches";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+
+      serviceConfig = {
+        DynamicUser = true;
+        Restart = "always";
+
+        # Hardening
+        NoNewPrivileges = true;
+        PrivateTmp = true;
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        CapabilityBoundingSet = "";
+      };
+
+      script =
+        let
+          args = lib.concatStringsSep " " (
+            [
+              "--address ${cfg.address}"
+              "--port ${toString cfg.port}"
+            ]
+            ++ lib.optional cfg.debug "--debug"
+            ++ lib.optional cfg.verbose "--verbose"
+            ++ lib.optional cfg.json "--json"
+          );
+        in
+        ''
+          export GS1200_PASSWORD=$(cat ${cfg.passwordFile})
+          exec ${lib.getExe pkgs.gs1200-exporter} ${args}
+        '';
+    };
+  };
+}

nixos/tests/all-tests.nix

@@ -692,6 +692,7 @@ in
   grocy = runTest ./grocy.nix;
   grow-partition = runTest ./grow-partition.nix;
   grub = runTest ./grub.nix;
+  gs1200-exporter = runTest ./gs1200-exporter.nix;
   guacamole-server = runTest ./guacamole-server.nix;
   guix = handleTest ./guix { };
   gvisor = runTest ./gvisor.nix;

nixos/tests/gs1200-exporter.nix

@@ -0,0 +1,20 @@
+{ lib, ... }:
+{
+  name = "gs1200-exporter";
+  meta.maintainers = with lib.maintainers; [ DerGrumpf ];
+  nodes.machine = _: {
+    services.gs1200-exporter = {
+      enable = true;
+      address = "192.168.2.4";
+      passwordFile = "/run/secrets/gs1200-password";
+    };
+    systemd.tmpfiles.rules = [
+      "f /run/secrets/gs1200-password 0400 root root - testpassword"
+    ];
+  };
+  testScript = ''
+    machine.wait_for_unit("gs1200-exporter.service")
+    machine.wait_for_open_port(9934)
+    machine.succeed("curl -f http://localhost:9934/metrics")
+  '';
+}