Started adding a nix flake

.gitignore

@@ -1,2 +1,4 @@
 virtenv
 waterfall.png
+__pycache__
+scripts

default.nix

@@ -0,0 +1,21 @@
+{ lib, python3Packages }:
+with python3Packages;
+buildPythonApplication {
+  pname = "satnogs-demo-display";
+  version = "1.0";
+
+  src = ./.;
+
+  propagatedBuildInputs = [
+    pillow
+    requests
+    pytz
+  ];
+
+  meta = with lib; {
+    description = "Satnogs Demo Display";
+    homepage = "https://forgejo.zenerdio.de/sebastian/satnogs-demo-display";
+    license = licenses.gpl2Plus;
+    platforms = platforms.unix;
+  };
+}

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1701282334,
+        "narHash": "sha256-MxCVrXY6v4QmfTwIysjjaX0XUhqBbxTWWB4HXtDYsdk=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "057f9aecfb71c4437d2b27d3323df7f93c010b7e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "23.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,44 @@
+{
+  description = "A flake for the piWatcher software.";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/23.11";
+  };
+
+
+  outputs = inputs@{ self, nixpkgs, ... }:
+    let
+      lib = nixpkgs.lib;
+
+      allSystems = [ "x86_64-linux" "aarch64-linux" "armv6l-linux" ];
+
+      crossPkgs-aarch64-linux = import nixpkgs { localSystem = "x86_64-linux"; crossSystem = "aarch64-linux"; };
+      crossPkgs-armv6l-linux = import nixpkgs {
+        localSystem = "x86_64-linux";
+        crossSystem = {
+          system = "armv6l-linux";
+          gcc = {
+            arch = "armv6k";
+            fpu = "vfp";
+          };
+        };
+      };
+    in
+    {
+      formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixpkgs-fmt;
+
+      packages = {
+        x86_64-linux = {
+          default = nixpkgs.legacyPackages.x86_64-linux.callPackage ./default.nix { };
+          cross-aarch64-linux = crossPkgs-aarch64-linux.callPackage ./default.nix { };
+          cross-armv6l-linux = crossPkgs-armv6l-linux.callPackage ./default.nix { };
+        };
+        aarch64-linux.default = nixpkgs.legacyPackages.aarch64-linux.callPackage ./default.nix { };
+        armv6l-linux.default = nixpkgs.legacyPackages.armv6l-linux.callPackage ./default.nix { };
+      };
+
+      nixosModules.default = { config, pkgs, ... }: {
+        imports = [ ./module.nix ];
+        _module.args.piwatcherPkgs = self.packages;
+      };
+    };
+}

module.nix

@@ -0,0 +1,81 @@
+{ lib, config, pkgs, satnogsDemoDisplayPkgs, ... }:
+with lib;
+let
+  # Shorter name to access final settings a 
+  # user of hello.nix module HAS ACTUALLY SET.
+  # cfg is a typical convention.
+  cfg = config.services.satnogsDemoDisplay;
+in
+{
+
+  options.services.satnogsDemoDisplay = {
+    enable = mkEnableOption "satnogs-demo-display service";
+
+    package = mkOption {
+      default = satnogsDemoDisplayPkgs.x86_64-linux.cross-armv6l-linux;
+      type = types.package;
+      description = "satnogsDemoDisplay packages to use. Needed to fix crosscompilation issues.";
+    };
+
+    user = mkOption {
+      type = types.str;
+      default = "satnogs-demo";
+      description = mdDoc "User to run the desktop environment and display script.";
+    };
+
+    group = mkOption {
+      type = types.str;
+      default = "satnogs-demo";
+      description = mdDoc "Group for the user.";
+    };
+
+
+    stateDir = mkOption {
+      default = "/var/lib/satnogs-demo-display";
+      type = types.str;
+      description = mdDoc "Demo display data directory.";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [
+      cfg.package
+    ];
+
+    users.users = mkIf (cfg.user == "satnogs-demo") {
+      satnogs-demo = {
+        home = cfg.stateDir;
+        useDefaultShell = true;
+        group = cfg.group;
+        isSystemUser = true;
+      };
+    };
+
+    systemd.tmpfiles.rules = [
+      "d '${cfg.stateDir}' 0750 ${cfg.user} ${cfg.group} - -"
+    ];
+
+    systemd.services.satnogsDemoDisplay = {
+      wantedBy = [ "multi-user.target" ];
+      description = "satnogsDemoDisplay service";
+      serviceConfig = {
+        Type = "exec";
+        User = cfg.user;
+        Group = cfg.group;
+        Restart = "always";
+        RestartSec = "1s";
+        StartLimitIntervalSec = "0";
+        WorkingDirectory = cfg.stateDir;
+      };
+      script = ''
+        ln -s ${cfg.package}/satnogs-logo.png ./
+        ln -s ${cfg.package}/Montserrat-Regular.otf ./
+
+        while true; do
+          ${cfg.package}/bin/update.py
+          sleep 60
+        done
+      '';
+    };
+  };
+}

result

@@ -0,0 +1 @@
+/nix/store/fxzpj6qdbgr6mcxs12004v71h2hzzqld-satnogs-demo-display-1.0

setup.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+import os
+import shutil
+
+from setuptools import setup, find_packages
+
+if not os.path.exists('scripts'):
+    os.makedirs('scripts')
+shutil.copyfile('update.py', 'scripts/satnogs-demo-display')
+
+setup(name='satnogs-demo-display',
+      version='1.0',
+      # Modules to import from other scripts:
+      packages=find_packages(),
+      data_files = [('', ['satnogs-logo.png', 'Montserrat-Regular.otf'])],
+      # Executables
+      scripts=["scripts/satnogs-demo-display"],
+     )