nixos/scanservjs: init

Init NixOS module for scanservjs

https://github.com/sbs20/scanservjs/

nixos/doc/manual/release-notes/rl-2505.section.md

@@ -14,6 +14,8 @@
 
 - [Bazecor](https://github.com/Dygmalab/Bazecor), the graphical configurator for Dygma Products.
 
+- [scanservjs](https://github.com/sbs20/scanservjs/), a web UI for SANE scanners. Available at [services.scanservjs](#opt-services.scanservjs.enable).
+
 - [Kimai](https://www.kimai.org/), a web-based multi-user time-tracking application. Available as [services.kimai](options.html#opt-services.kimai).
 
 - [Omnom](https://github.com/asciimoo/omnom), a webpage bookmarking and snapshotting service. Available as [services.omnom](options.html#opt-services.omnom.enable).

nixos/modules/module-list.nix

@@ -621,6 +621,7 @@
   ./services/hardware/sane_extra_backends/brscan4.nix
   ./services/hardware/sane_extra_backends/brscan5.nix
   ./services/hardware/sane_extra_backends/dsseries.nix
+  ./services/hardware/scanservjs.nix
   ./services/hardware/spacenavd.nix
   ./services/hardware/supergfxd.nix
   ./services/hardware/tcsd.nix

nixos/modules/services/hardware/scanservjs.nix

@@ -0,0 +1,155 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  cfg = config.services.scanservjs;
+  settings = {
+    scanimage = lib.getExe' config.hardware.sane.backends-package "scanimage";
+    convert = lib.getExe' pkgs.imagemagick "convert";
+    tesseract = lib.getExe pkgs.tesseract;
+    # it defaults to config/devices.json, but "config" dir doesn't exist by default and scanservjs doesn't create it
+    devicesPath = "devices.json";
+  } // cfg.settings;
+  settingsFormat = pkgs.formats.json { };
+
+  leafs =
+    attrs:
+    builtins.concatLists (
+      lib.mapAttrsToList (k: v: if builtins.isAttrs v then leafs v else [ v ]) attrs
+    );
+
+  package = pkgs.scanservjs;
+
+  configFile = pkgs.writeText "config.local.js" ''
+    /* eslint-disable no-unused-vars */
+    module.exports = {
+      afterConfig(config) {
+        ${
+          builtins.concatStringsSep "" (
+            leafs (
+              lib.mapAttrsRecursive (path: val: ''
+                ${builtins.concatStringsSep "." path} = ${builtins.toJSON val};
+              '') { config = settings; }
+            )
+          )
+        }
+        ${cfg.extraConfig}
+      },
+
+      afterDevices(devices) {
+        ${cfg.extraDevicesConfig}
+      },
+
+      async afterScan(fileInfo) {
+        ${cfg.runAfterScan}
+      },
+
+      actions: [
+        ${builtins.concatStringsSep ",\n" cfg.extraActions}
+      ],
+    };
+  '';
+
+in
+{
+  options.services.scanservjs = {
+    enable = lib.mkEnableOption "scanservjs";
+    stateDir = lib.mkOption {
+      type = lib.types.str;
+      default = "/var/lib/scanservjs";
+      description = ''
+        State directory for scanservjs.
+      '';
+    };
+    settings = lib.mkOption {
+      default = { };
+      description = ''
+        Config to set in config.local.js's `afterConfig`.
+      '';
+      type = lib.types.submodule {
+        freeformType = settingsFormat.type;
+        options.host = lib.mkOption {
+          type = lib.types.str;
+          description = "The IP to listen on.";
+          default = "127.0.0.1";
+        };
+        options.port = lib.mkOption {
+          type = lib.types.port;
+          description = "The port to listen on.";
+          default = 8080;
+        };
+      };
+    };
+    extraConfig = lib.mkOption {
+      default = "";
+      type = lib.types.lines;
+      description = ''
+        Extra code to add to config.local.js's `afterConfig`.
+      '';
+    };
+    extraDevicesConfig = lib.mkOption {
+      default = "";
+      type = lib.types.lines;
+      description = ''
+        Extra code to add to config.local.js's `afterDevices`.
+      '';
+    };
+    runAfterScan = lib.mkOption {
+      default = "";
+      type = lib.types.lines;
+      description = ''
+        Extra code to add to config.local.js's `afterScan`.
+      '';
+    };
+    extraActions = lib.mkOption {
+      default = [ ];
+      type = lib.types.listOf lib.types.lines;
+      description = "Actions to add to config.local.js's `actions`.";
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    hardware.sane.enable = true;
+    users.users.scanservjs = {
+      group = "scanservjs";
+      extraGroups = [
+        "scanner"
+        "lp"
+      ];
+      home = cfg.stateDir;
+      isSystemUser = true;
+      createHome = true;
+    };
+    users.groups.scanservjs = { };
+
+    systemd.services.scanservjs = {
+      description = "scanservjs";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      # yes, those paths are configurable, but the config option isn't always used...
+      # a lot of the time scanservjs just takes those from PATH
+      path = with pkgs; [
+        coreutils
+        config.hardware.sane.backends-package
+        imagemagick
+        tesseract
+      ];
+      environment = {
+        NIX_SCANSERVJS_CONFIG_PATH = configFile;
+        SANE_CONFIG_DIR = "/etc/sane-config";
+        LD_LIBRARY_PATH = "/etc/sane-libs";
+      };
+      serviceConfig = {
+        ExecStart = lib.getExe package;
+        Restart = "always";
+        User = "scanservjs";
+        Group = "scanservjs";
+        WorkingDirectory = cfg.stateDir;
+      };
+    };
+  };
+}