nixos/goss: init

nixos/doc/manual/release-notes/rl-2311.section.md

···
 
 - [pgBouncer](https://www.pgbouncer.org), a PostgreSQL connection pooler. Available as [services.pgbouncer](#opt-services.pgbouncer.enable).
 
+- [Goss](https://goss.rocks/), a YAML based serverspec alternative tool for validating a server's configuration. Available as [services.goss](#opt-services.goss.enable).
+
 - [trust-dns](https://trust-dns.org/), a Rust based DNS server built to be safe and secure from the ground up. Available as [services.trust-dns](#opt-services.trust-dns.enable).
 
 - [osquery](https://www.osquery.io/), a SQL powered operating system instrumentation, monitoring, and analytics.

nixos/modules/module-list.nix

···
   ./services/monitoring/datadog-agent.nix
   ./services/monitoring/do-agent.nix
   ./services/monitoring/fusion-inventory.nix
+  ./services/monitoring/goss.nix
   ./services/monitoring/grafana-agent.nix
   ./services/monitoring/grafana-image-renderer.nix
   ./services/monitoring/grafana-reporter.nix

nixos/modules/services/monitoring/goss.md

···
+# Goss {#module-services-goss}
+
+[goss](https://goss.rocks/) is a YAML based serverspec alternative tool
+for validating a server's configuration.
+
+## Basic Usage {#module-services-goss-basic-usage}
+
+A minimal configuration looks like this:
+
+```
+{
+  services.goss = {
+    enable = true;
+
+    environment = {
+      GOSS_FMT = "json";
+      GOSS_LOGLEVEL = "TRACE";
+    };
+
+    settings = {
+      addr."tcp://localhost:8080" = {
+        reachable = true;
+        local-address = "127.0.0.1";
+      };
+      command."check-goss-version" = {
+        exec = "${lib.getExe pkgs.goss} --version";
+        exit-status = 0;
+      };
+      dns.localhost.resolvable = true;
+      file."/nix" = {
+        filetype = "directory";
+        exists = true;
+      };
+      group.root.exists = true;
+      kernel-param."kernel.ostype".value = "Linux";
+      service.goss = {
+        enabled = true;
+        running = true;
+      };
+      user.root.exists = true;
+    };
+  };
+}
+```

nixos/modules/services/monitoring/goss.nix

···
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.services.goss;
+
+  settingsFormat = pkgs.formats.yaml { };
+  configFile = settingsFormat.generate "goss.yaml" cfg.settings;
+
+in {
+  meta = {
+    doc = ./goss.md;
+    maintainers = [ lib.maintainers.anthonyroussel ];
+  };
+
+  options = {
+    services.goss = {
+      enable = lib.mkEnableOption (lib.mdDoc "Goss daemon");
+
+      package = lib.mkPackageOptionMD pkgs "goss" { };
+
+      environment = lib.mkOption {
+        type = lib.types.attrsOf lib.types.str;
+        default = { };
+        example = {
+          GOSS_FMT = "json";
+          GOSS_LOGLEVEL = "FATAL";
+          GOSS_LISTEN = ":8080";
+        };
+        description = lib.mdDoc ''
+          Environment variables to set for the goss service.
+
+          See <https://github.com/goss-org/goss/blob/master/docs/manual.md>
+        '';
+      };
+
+      settings = lib.mkOption {
+        type = lib.types.submodule { freeformType = settingsFormat.type; };
+        default = { };
+        example = {
+          addr."tcp://localhost:8080" = {
+            reachable = true;
+            local-address = "127.0.0.1";
+          };
+          service.goss = {
+            enabled = true;
+            running = true;
+          };
+        };
+        description = lib.mdDoc ''
+          The global options in `config` file in yaml format.
+
+          Refer to <https://github.com/goss-org/goss/blob/master/docs/goss-json-schema.yaml> for schema.
+        '';
+      };
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [ cfg.package ];
+
+    systemd.services.goss = {
+      description = "Goss - Quick and Easy server validation";
+      unitConfig.Documentation = "https://github.com/goss-org/goss/blob/master/docs/manual.md";
+
+      after = [ "network-online.target" ];
+      wantedBy = [ "multi-user.target" ];
+      wants = [ "network-online.target" ];
+
+      environment = {
+        GOSS_FILE = configFile;
+      } // cfg.environment;
+
+      reloadTriggers = [ configFile ];
+
+      serviceConfig = {
+        DynamicUser = true;
+        ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
+        ExecStart = "${cfg.package}/bin/goss serve";
+        Group = "goss";
+        Restart = "on-failure";
+        RestartSec = 5;
+        User = "goss";
+      };
+    };
+  };
+}