Create module

flake.nix

@@ -17,6 +17,11 @@
       "x86_64-linux"
     ];
   in {
+    nixosModules = rec {
+      hcpy = import ./module.nix self;
+      default = hcpy;
+    };
+
     packages = eachSystem (system: let
       pkgs = nixpkgs.legacyPackages.${system};
     in rec {

module.nix

@@ -0,0 +1,102 @@
+self: {
+  config,
+  lib,
+  pkgs,
+  system,
+  ...
+}:
+with lib; let
+  cfg = config.services.hcpy;
+  bridgeConfig =
+    cfg.config
+    // {
+      devices_file = cfg.devicesFile;
+    };
+  hcpy = pkgs.writeShellApplication {
+    name = "hcpy-service";
+    runtimeInputs = [self.packages.${system}.default];
+    text = ''
+      if [ ! -f "${cfg.devicesFile}" ]; then
+        echo "Device file does not exist, requesting login to HomeConnect cloud";
+        hcpy login "$(cat "${cfg.homeconnect.usernameFile}")" \
+                   "$(cat "${cfg.homeconnect.passwordFile}")" \
+                   "${cfg.devicesFile}";
+      fi
+
+      hcpy run ${cli.toGNUCommandLineShell {} bridgeConfig} \
+          --mqtt_username "$(cat "${cfg.mqtt.usernameFile}")" \
+          --mqtt_password "$(cat "${cfg.mqtt.passwordFile}")"
+    '';
+  };
+in {
+  options.services.hcpy = {
+    enable = mkEnableOption "HomeConnect bridge service";
+
+    homeconnect = {
+      usernameFile = mkOption {
+        type = types.path;
+        description = "Path to file containing single line with HomeConnect account username";
+        example = "/run/hc.username.key";
+      };
+
+      passwordFile = mkOption {
+        type = types.path;
+        description = "Path to file containing single line with HomeConnect account password";
+        example = "/run/hc.password.key";
+      };
+    };
+
+    mqtt = {
+      usernameFile = mkOption {
+        type = types.path;
+        description = "Path to file containing single line with MQTT client username";
+        example = "/run/mqtt.username.key";
+      };
+
+      passwordFile = mkOption {
+        type = types.path;
+        description = "Path to file containing single line with MQTT client password";
+        example = "/run/mqtt.password.key";
+      };
+    };
+
+    devicesFile = mkOption {
+      type = types.path;
+      description = "Path to JSON file fetched from HomeConnect API";
+      example = "/var/lib/hcpy/devices.json";
+    };
+
+    config = mkOption {
+      type = types.attrs;
+      description = "The configuration of hcpy bridge";
+      example = {
+        mqtt_host = "localhost";
+        mqtt_prefix = "homeconnect/";
+        mqtt_port = 8883;
+        mqtt_ssl = true;
+        mqtt_cafile = "/run/ca.pem";
+        mqtt_certfile = "/run/cert.crt";
+        mqtt_keyfile = "/run/cert.key";
+        mqtt_clientname = "hcpy1";
+        domain_suffix = "";
+        debug = true;
+        ha-discovery = true;
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.hcpy = {
+      enable = true;
+      description = "HomeConnect bridge service";
+
+      wantedBy = ["multi-user.target"];
+      wants = ["network-online.target"];
+      after = ["network-online.target"];
+
+      serviceConfig = {
+        ExecStart = "${hcpy}/bin/hcpy-service";
+      };
+    };
+  };
+}