1 files changed, 128 insertions, 0 deletions
diff --git a/nixos/modules/services/monitoring/karma.nix b/nixos/modules/services/monitoring/karma.nix
new file mode 100644
index 00000000000..85dbc81f443
--- /dev/null
+++ b/nixos/modules/services/monitoring/karma.nix
@@ -0,0 +1,128 @@
+{ config, pkgs, lib, ... }:
+with lib;
+let
+  cfg = config.services.karma;
+  yaml = pkgs.formats.yaml { };
+in
+{
+  options.services.karma = {
+    enable = mkEnableOption (mdDoc "the Karma dashboard service");
+
+    package = mkOption {
+      type = types.package;
+      default = pkgs.karma;
+      defaultText = literalExpression "pkgs.karma";
+      description = mdDoc ''
+        The Karma package that should be used.
+      '';
+    };
+
+    configFile = mkOption {
+      type = types.path;
+      default = yaml.generate "karma.yaml" cfg.settings;
+      defaultText = "A configuration file generated from the provided nix attributes settings option.";
+      description = mdDoc ''
+        A YAML config file which can be used to configure karma instead of the nix-generated file.
+      '';
+      example = "/etc/karma/karma.conf";
+    };
+
+    environment = mkOption {
+      type = with types; attrsOf str;
+      default = {};
+      description = mdDoc ''
+        Additional environment variables to provide to karma.
+      '';
+      example = {
+        ALERTMANAGER_URI = "https://alertmanager.example.com";
+        ALERTMANAGER_NAME= "single";
+      };
+    };
+
+    openFirewall = mkOption {
+      type = types.bool;
+      default = false;
+      description = mdDoc ''
+        Whether to open ports in the firewall needed for karma to function.
+      '';
+    };
+
+    extraOptions = mkOption {
+      type = with types; listOf str;
+      default = [];
+      description = mdDoc ''
+        Extra command line options.
+      '';
+      example = [
+        "--alertmanager.timeout 10s"
+      ];
+    };
+
+    settings = mkOption {
+      type = types.submodule {
+        freeformType = yaml.type;
+
+        options.listen = {
+          address = mkOption {
+            type = types.str;
+            default = "127.0.0.1";
+            description = mdDoc ''
+              Hostname or IP to listen on.
+            '';
+            example = "[::]";
+          };
+
+          port = mkOption {
+            type = types.port;
+            default = 8080;
+            description = mdDoc ''
+              HTTP port to listen on.
+            '';
+            example = 8182;
+          };
+        };
+      };
+      default = {
+        listen = {
+          address = "127.0.0.1";
+        };
+      };
+      description = mdDoc ''
+        Karma dashboard configuration as nix attributes.
+
+        Reference: <https://github.com/prymitive/karma/blob/main/docs/CONFIGURATION.md>
+      '';
+      example = {
+        listen = {
+          address = "192.168.1.4";
+          port = "8000";
+          prefix = "/dashboard";
+        };
+        alertmanager = {
+          interval = "15s";
+          servers = [
+            {
+              name = "prod";
+              uri = "http://alertmanager.example.com";
+            }
+          ];
+        };
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.karma = {
+      description = "Alert dashboard for Prometheus Alertmanager";
+      wantedBy = [ "multi-user.target" ];
+      environment = cfg.environment;
+      serviceConfig = {
+        Type = "simple";
+        DynamicUser = true;
+        Restart = "on-failure";
+        ExecStart = "${pkgs.karma}/bin/karma --config.file ${cfg.configFile} ${concatStringsSep " " cfg.extraOptions}";
+      };
+    };
+    networking.firewall.allowedTCPPorts = mkIf cfg.openFirewall [ cfg.settings.listen.port ];
+  };
+}