Add flake, module

module.nix

@@ -0,0 +1,79 @@
+{
+  config,
+  lib,
+  pkgs,
+  utils,
+  ...
+}: let
+  cfg = config.services.matrixoidc;
+in {
+  meta.maintainers = with lib.maintainers; [quadradical];
+  options.services.matrixoidc = {
+    enable = lib.mkEnableOption "the matrixoidc server";
+    package = lib.mkPackageOption pkgs "matrixoidc" {};
+
+    group = lib.mkOption {
+      type = lib.types.string;
+    };
+
+    jwtSecretFile = lib.mkOption {
+      type = lib.types.path;
+    };
+
+    args = lib.mkOption {
+      type = lib.types.string;
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.services.matrixoidc = {
+      description = "matrixoidc server";
+      documentation = ["https://git.federated.nexus/Henry-Hiles/matrixoidc"];
+      wantedBy = ["multi-user.target"];
+      wants = ["network-online.target"];
+      after = ["network-online.target"];
+
+      serviceConfig = {
+        LoadCredential = ["matrixoidc-secrets:${cfg.jwtSecretFile}"];
+        ExecStart = utils.escapeSystemdExecArgs [
+          (lib.getExe cfg.package)
+          cfg.args
+          "--jwtSecretFile=/run/credentials/matrixoidc.service/matrixoidc-secrets"
+        ];
+        DynamicUser = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateUsers = true;
+        RestrictAddressFamilies = [
+          "AF_INET"
+          "AF_INET6"
+          "AF_NETLINK"
+        ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        ProtectHome = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [
+          "@system-service"
+          "~@privileged"
+          "~@resources"
+        ];
+        Restart = "on-failure";
+        RestartSec = 5;
+        UMask = "077";
+
+        RuntimeDirectory = "matrixoidc";
+        RuntimeDirectoryMode = 0770;
+        Group = cfg.group;
+      };
+    };
+  };
+}