Got my NixOS flake to run under WSL!

2025-07-06 06:52:13 +05:30 · 2023-08-20 17:55:05 -05:00 · 2023-08-20 17:55:05 -05:00 · 0a71232a56
commit 0a71232a56
parent e877fd63bc
18 changed files with 1063 additions and 10 deletions
--- a/profiles/wsl/nixos-wsl/modules/wsl-distro.nix
+++ b/profiles/wsl/nixos-wsl/modules/wsl-distro.nix
@ -0,0 +1,139 @@
+{ lib, pkgs, config, ... }:
+
+with builtins; with lib;
+{
+  options.wsl = with types;
+    let
+      coercedToStr = coercedTo (oneOf [ bool path int ]) (toString) str;
+    in
+    {
+      enable = mkEnableOption "support for running NixOS as a WSL distribution";
+      automountPath = mkOption {
+        type = str;
+        default = "/mnt";
+        description = "The path where windows drives are mounted (e.g. /mnt/c)";
+      };
+      automountOptions = mkOption {
+        type = str;
+        default = "metadata,uid=1000,gid=100";
+        description = "Options to use when mounting windows drives";
+      };
+      defaultUser = mkOption {
+        type = str;
+        default = "nixos";
+        description = "The name of the default user";
+      };
+      startMenuLaunchers = mkEnableOption "shortcuts for GUI applications in the windows start menu";
+      wslConf = mkOption {
+        type = attrsOf (attrsOf (oneOf [ str int bool ]));
+        description = "Entries that are added to /etc/wsl.conf";
+      };
+    };
+
+  config =
+    let
+      cfg = config.wsl;
+      syschdemd = import ../syschdemd.nix { inherit lib pkgs config; inherit (cfg) automountPath defaultUser; defaultUserHome = config.users.users.${cfg.defaultUser}.home; };
+    in
+    mkIf cfg.enable {
+
+      wsl.wslConf = {
+        automount = {
+          enabled = true;
+          mountFsTab = true;
+          root = "${cfg.automountPath}/";
+          options = cfg.automountOptions;
+        };
+        network = {
+          generateResolvConf = mkDefault true;
+          generateHosts = mkDefault true;
+        };
+      };
+
+      # WSL is closer to a container than anything else
+      boot.isContainer = true;
+
+      environment.noXlibs = lib.mkForce false; # override xlibs not being installed (due to isContainer) to enable the use of GUI apps
+      hardware.opengl.enable = true; # Enable GPU acceleration
+
+      environment = {
+
+        etc = {
+          "wsl.conf".text = generators.toINI { } cfg.wslConf;
+
+          # DNS settings are managed by WSL
+          hosts.enable = !config.wsl.wslConf.network.generateHosts;
+          "resolv.conf".enable = !config.wsl.wslConf.network.generateResolvConf;
+        };
+
+        systemPackages = [
+          (pkgs.runCommand "wslpath" { } ''
+            mkdir -p $out/bin
+            ln -s /init $out/bin/wslpath
+          '')
+        ];
+      };
+
+      networking.dhcpcd.enable = false;
+
+      users.users.${cfg.defaultUser} = {
+        isNormalUser = true;
+        uid = 1000;
+        extraGroups = [ "wheel" ]; # Allow the default user to use sudo
+      };
+
+      users.users.root = {
+        shell = "${syschdemd}/bin/syschdemd";
+        # Otherwise WSL fails to login as root with "initgroups failed 5"
+        extraGroups = [ "root" ];
+      };
+
+      security.sudo = {
+        extraConfig = ''
+          Defaults env_keep+=INSIDE_NAMESPACE
+        '';
+        wheelNeedsPassword = mkDefault false; # The default user will not have a password by default
+      };
+
+      system.activationScripts = {
+        copy-launchers = mkIf cfg.startMenuLaunchers (
+          stringAfter [ ] ''
+            for x in applications icons; do
+              echo "Copying /usr/share/$x"
+              mkdir -p /usr/share/$x
+              ${pkgs.rsync}/bin/rsync -ar --delete $systemConfig/sw/share/$x/. /usr/share/$x
+            done
+          ''
+        );
+        populateBin = stringAfter [ ] ''
+          echo "setting up /bin..."
+          ln -sf /init /bin/wslpath
+          ln -sf ${pkgs.bashInteractive}/bin/bash /bin/sh
+          ln -sf ${pkgs.util-linux}/bin/mount /bin/mount
+        '';
+      };
+
+      systemd = {
+        # Disable systemd units that don't make sense on WSL
+        services = {
+          "serial-getty@ttyS0".enable = false;
+          "serial-getty@hvc0".enable = false;
+          "getty@tty1".enable = false;
+          "autovt@".enable = false;
+          firewall.enable = false;
+          systemd-resolved.enable = false;
+          systemd-udevd.enable = false;
+        };
+
+        tmpfiles.rules = [
+          # Don't remove the X11 socket
+          "d /tmp/.X11-unix 1777 root root"
+        ];
+
+        # Don't allow emergency mode, because we don't have a console.
+        enableEmergencyMode = false;
+      };
+
+      warnings = (optional (config.systemd.services.systemd-resolved.enable && config.wsl.wslConf.network.generateResolvConf) "systemd-resolved is enabled, but resolv.conf is managed by WSL");
+    };
+}