Merge pull request #766 from Enzime/disko-vm

Add `virtualisation.vmVariantWithDisko` option

docs/interactive-vm.md

@@ -12,6 +12,16 @@ afterwards you can run the interactive VM with:
 result/bin/disko-vm
 ```
 
+You can configure the VM using the `virtualisation.vmVariantWithDisko` NixOS option:
+
+```nix
+{
+  virtualisation.vmVariantWithDisko = {
+    virtualisation.fileSystems."/persist".neededForBoot = true;
+  };
+}
+```
+
 extraConfig that is set in disko.tests.extraConfig is also applied to the interactive VMs.
 imageSize of the VMs will be determined by the imageSize in the disk type in your disko config.
 memorySize is set by disko.memSize

lib/default.nix

@@ -16,8 +16,6 @@ let
     # a version of makeDiskImage which runs outside of the store
     makeDiskImagesScript = args: (import ./make-disk-image.nix ({ inherit diskoLib; } // args)).impure;
 
-    makeVMRunner = args: (import ./interactive-vm.nix ({ inherit diskoLib; } // args)).pure;
-
     testLib = import ./tests.nix { inherit lib makeTest eval-config; };
     # like lib.types.oneOf but instead of a list takes an attrset
     # uses the field "type" to find the correct type in the attrset

lib/interactive-vm.nix

@@ -1,12 +1,9 @@
-{ nixosConfig
-, diskoLib
-, pkgs ? nixosConfig.pkgs
-, name ? "${nixosConfig.config.networking.hostName}-disko-images"
-, extraConfig ? { }
-}:
+# We need to specify extendModules here to ensure that it is available
+# in args for makeDiskImages
+{ diskoLib, modulesPath, config, pkgs, lib, extendModules, ... }@args:
+
 let
-  lib = pkgs.lib;
-  vm_disko = (diskoLib.testLib.prepareDiskoConfig nixosConfig.config diskoLib.testLib.devices).disko;
+  vm_disko = (diskoLib.testLib.prepareDiskoConfig config diskoLib.testLib.devices).disko;
   cfg_ = (lib.evalModules {
     modules = lib.singleton {
       # _file = toString input;
@@ -24,7 +21,7 @@ let
   }).config;
   disks = lib.attrValues cfg_.disko.devices.disk;
   diskoImages = diskoLib.makeDiskImages {
-    nixosConfig = nixosConfig;
+    nixosConfig = args;
     copyNixStore = false;
     extraConfig = {
       disko.devices = cfg_.disko.devices;
@@ -47,34 +44,29 @@ let
       driveExtraOpts.werror = "report";
     })
     (builtins.tail disks);
-  vm = (nixosConfig.extendModules {
-    modules = [
-      ({ modulesPath, ... }: {
-        imports = [
-          (modulesPath + "/virtualisation/qemu-vm.nix")
-        ];
-      })
-      {
-        virtualisation.useEFIBoot = nixosConfig.config.disko.tests.efi;
-        virtualisation.memorySize = nixosConfig.config.disko.memSize;
-        virtualisation.useDefaultFilesystems = false;
-        virtualisation.diskImage = null;
-        virtualisation.qemu.drives = [ rootDisk ] ++ otherDisks;
-        boot.zfs.devNodes = "/dev/disk/by-uuid"; # needed because /dev/disk/by-id is empty in qemu-vms
-        boot.zfs.forceImportAll = true;
-      }
-      {
-        # generated from disko config
-        virtualisation.fileSystems = cfg_.disko.devices._config.fileSystems;
-        boot = cfg_.disko.devices._config.boot or { };
-        swapDevices = cfg_.disko.devices._config.swapDevices or [ ];
-      }
-      nixosConfig.config.disko.tests.extraConfig
-    ];
-  }).config.system.build.vm;
+
+  diskoBasedConfiguration = {
+    # generated from disko config
+    virtualisation.fileSystems = cfg_.disko.devices._config.fileSystems;
+    boot = cfg_.disko.devices._config.boot or { };
+    swapDevices = cfg_.disko.devices._config.swapDevices or [ ];
+  };
 in
 {
-  pure = pkgs.writers.writeDashBin "disko-vm" ''
+  imports = [
+    (modulesPath + "/virtualisation/qemu-vm.nix")
+    diskoBasedConfiguration
+  ];
+
+  virtualisation.useEFIBoot = config.disko.tests.efi;
+  virtualisation.memorySize = config.disko.memSize;
+  virtualisation.useDefaultFilesystems = false;
+  virtualisation.diskImage = null;
+  virtualisation.qemu.drives = [ rootDisk ] ++ otherDisks;
+  boot.zfs.devNodes = "/dev/disk/by-uuid"; # needed because /dev/disk/by-id is empty in qemu-vms
+  boot.zfs.forceImportAll = true;
+
+  system.build.vmWithDisko = pkgs.writers.writeDashBin "disko-vm" ''
     set -efux
     export tmp=$(mktemp -d)
     trap 'rm -rf "$tmp"' EXIT
@@ -84,6 +76,6 @@ in
       -F qcow2 "$tmp"/${disk.name}.qcow2
     '') disks}
     set +f
-    ${vm}/bin/run-*-vm
+    ${config.system.build.vm}/bin/run-*-vm
   '';
 }

module.nix

@@ -7,6 +7,14 @@ let
     eval-config = import (pkgs.path + "/nixos/lib/eval-config.nix");
   };
   cfg = config.disko;
+
+  vmVariantWithDisko = extendModules {
+    modules = [
+      ./lib/interactive-vm.nix
+      { _module.args = { inherit diskoLib; }; }
+      config.disko.tests.extraConfig
+    ];
+  };
 in
 {
   options.disko = {
@@ -137,6 +145,16 @@ in
       };
     };
   };
+
+  options.virtualisation.vmVariantWithDisko = lib.mkOption {
+    description = ''
+      Machine configuration to be added for the vm script available at `.system.build.vmWithDisko`.
+    '';
+    inherit (vmVariantWithDisko) type;
+    default = {};
+    visible = "shallow";
+  };
+
   config = lib.mkIf (cfg.devices.disk != { }) {
     system.build = (cfg.devices._scripts { inherit pkgs; checked = cfg.checkScripts; }) // {
 
@@ -161,10 +179,7 @@ in
         extraTestScript = cfg.tests.extraChecks;
       };
 
-      vmWithDisko = diskoLib.makeVMRunner {
-        inherit pkgs;
-        nixosConfig = args;
-      };
+      vmWithDisko = lib.mkDefault config.virtualisation.vmVariantWithDisko.system.build.vmWithDisko;
     };