Move nix code under nix/

nix/lib.nix

@@ -0,0 +1,34 @@
+{ nixpkgs }:
+let
+  inherit (nixpkgs) lib;
+in
+{
+  makeServiceConfig = { system, module }:
+    let
+      pkgs = nixpkgs.legacyPackages.${system};
+
+      nixosConfig = lib.nixosSystem {
+        inherit system;
+        specialArgs = { };
+        modules = [ module ];
+      };
+      services = lib.flip lib.genAttrs
+        (serviceName:
+          nixosConfig.config.systemd.units."${serviceName}.service".unit)
+        nixosConfig.config.service-manager.services;
+
+      servicesPath =
+        pkgs.writeTextFile {
+          name = "services";
+          destination = "/services.json";
+          text = lib.generators.toJSON { } services;
+        };
+      activationScript = pkgs.writeShellScript "activate" ''
+        echo "${servicesPath}"
+      '';
+    in
+    pkgs.linkFarmFromDrvs "service-manager" [
+      servicesPath
+      activationScript
+    ];
+}

nix/modules/default.nix

@@ -0,0 +1,57 @@
+{ lib, pkgs, ... }:
+
+let
+  service-1 = "service-1";
+  service-2 = "service-2";
+
+  services = {
+    ${service-1} = {
+      enable = true;
+      description = service-1;
+      wants = [ "network-online.target" ];
+      after = [
+        "network-online.target"
+        "avahi-daemon.service"
+        "chrony.service"
+        "nss-lookup.target"
+        "tinc.service"
+        "pulseaudio.service"
+      ];
+      serviceConfig = {
+        Type = "oneshot";
+        RemainAfterExit = true;
+        script = ''
+          true
+        '';
+        ExecReload = "true";
+      };
+      wantedBy = [ "multi-user.target" ];
+    };
+
+    ${service-2} = {
+      enable = true;
+      description = service-2;
+      serviceConfig = {
+        Type = "simple";
+      };
+      partOf = [ "${service-1}.service" ];
+      wantedBy = [ "${service-1}.service" ];
+
+      script = ''
+        true
+      '';
+    };
+  };
+in
+{
+  options = {
+    service-manager.services = lib.mkOption {
+      type = with lib.types; listOf str;
+    };
+  };
+
+  config = {
+    service-manager.services = lib.attrNames services;
+    systemd = { inherit services; };
+  };
+}