gitlab-runner service: initial version

nixos/modules/services/continuous-integration/gitlab-runner.nix

@@ -0,0 +1,51 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.gitlab-runner;
+  configFile = pkgs.writeText "config.toml" cfg.configText;
+in
+{
+  options.services.gitlab-runner = {
+    enable = mkEnableOption "Gitlab Runner";
+
+    configText = mkOption {
+      description = "Verbatim config.toml to use";
+    };
+
+    workDir = mkOption {
+      default = "/var/lib/gitlab-runner";
+      type = types.path;
+      description = "The working directory used";
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.gitlab-runner = {
+      description = "Gitlab Runner";
+      after = [ "network.target" "docker.service" ];
+      requires = [ "docker.service" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        ExecStart = ''${pkgs.gitlab-runner.bin}/bin/gitlab-runner run \
+          --working-directory ${cfg.workDir} \
+          --config ${configFile} \
+          --service gitlab-runner \
+          --user gitlab-runner \
+        '';
+      };
+    };
+
+    users.extraUsers.gitlab-runner = {
+      group = "gitlab-runner";
+      extraGroups = [ "docker" ];
+      uid = config.ids.uids.gitlab-runner;
+      home = cfg.workDir;
+      createHome = true;
+    };
+
+    users.extraGroups.gitlab-runner.gid = config.ids.gids.gitlab-runner;
+  };
+}