module: add vmWithDisko output to system

docs/interactive-vm.md

@@ -0,0 +1,17 @@
+# Running Interactive VMs with disko
+
+disko now exports it's own flavor of interactive VMs (similiar to config.system.build.vm).
+Simply import the disko module and build the vm runner with:
+```
+nix build -L '.#nixosConfigurations.mymachine.config.system.build.vmWithDisko'
+```
+
+afterwards you can run the interactive VM with:
+
+```
+result/bin/disko-vm
+```
+
+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

@@ -16,6 +16,8 @@ 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

@@ -0,0 +1,88 @@
+{ nixosConfig
+, diskoLib
+, pkgs ? nixosConfig.pkgs
+, name ? "${nixosConfig.config.networking.hostName}-disko-images"
+, extraConfig ? { }
+}:
+let
+  lib = pkgs.lib;
+  vm_disko = (diskoLib.testLib.prepareDiskoConfig nixosConfig.config diskoLib.testLib.devices).disko;
+  cfg_ = (lib.evalModules {
+    modules = lib.singleton {
+      # _file = toString input;
+      imports = lib.singleton { disko.devices = vm_disko.devices; };
+      options = {
+        disko.devices = lib.mkOption {
+          type = diskoLib.toplevel;
+        };
+        disko.testMode = lib.mkOption {
+          type = lib.types.bool;
+          default = true;
+        };
+      };
+    };
+  }).config;
+  disks = lib.attrValues cfg_.disko.devices.disk;
+  diskoImages = diskoLib.makeDiskImages {
+    nixosConfig = nixosConfig;
+    copyNixStore = false;
+    extraConfig = {
+      disko.devices = cfg_.disko.devices;
+    };
+    testMode = true;
+  };
+  rootDisk = {
+    name = "root";
+    file = ''"$tmp"/${(builtins.head disks).name}.qcow2'';
+    driveExtraOpts.cache = "writeback";
+    driveExtraOpts.werror = "report";
+    deviceExtraOpts.bootindex = "1";
+    deviceExtraOpts.serial = "root";
+  };
+  otherDisks = map
+    (disk: {
+      name = disk.name;
+      file = ''"$tmp"/${disk.name}.qcow2'';
+      driveExtraOpts.werror = "report";
+    })
+    (builtins.tail disks);
+  vm = (nixosConfig.extendModules {
+    modules = [
+      ({ modulesPath, ... }: {
+        imports = [
+          (modulesPath + "/virtualisation/qemu-vm.nix")
+        ];
+      })
+      {
+        virtualisation.useEFIBoot = nixosConfig.config.disko.tests.efi;
+        virtualisation.memorySize = nixosConfig.config.disko.memSize;
+        virtualisation.useDefaultFilesystems = false;
+        virtualisation.diskImage = null;
+        virtualisation.qemu.drives = [ rootDisk ] ++ otherDisks;
+        boot.zfs.devNodes = "/dev/disk/by-uuid"; # needed because /dev/disk/by-id is empty in qemu-vms
+        boot.zfs.forceImportAll = true;
+      }
+      {
+        # generated from disko config
+        virtualisation.fileSystems = cfg_.disko.devices._config.fileSystems;
+        boot = cfg_.disko.devices._config.boot or { };
+        swapDevices = cfg_.disko.devices._config.swapDevices or [ ];
+      }
+      nixosConfig.config.disko.tests.extraConfig
+    ];
+  }).config.system.build.vm;
+in
+{
+  pure = pkgs.writeDashBin "disko-vm" ''
+    set -efux
+    export tmp=$(mktemp -d)
+    trap 'rm -rf "$tmp"' EXIT
+    ${lib.concatMapStringsSep "\n" (disk: ''
+      ${pkgs.qemu}/bin/qemu-img create -f qcow2 \
+      -b ${diskoImages}/${disk.name}.raw \
+      -F raw "$tmp"/${disk.name}.qcow2
+    '') disks}
+    set +f
+    ${vm}/bin/run-*-vm
+  '';
+}

module.nix

@@ -69,6 +69,15 @@ in
       type = lib.types.bool;
       default = false;
     };
+    testMode = lib.mkOption {
+      internal = true;
+      description = ''
+        this is true if the system is being run in test mode.
+        like a vm test or an interactive vm
+      '';
+      type = lib.types.bool;
+      default = false;
+    };
     tests = {
       efi = lib.mkOption {
         description = ''
@@ -121,6 +130,11 @@ in
         extraSystemConfig = cfg.tests.extraConfig;
         extraTestScript = cfg.tests.extraChecks;
       };
+
+      vmWithDisko = diskoLib.makeVMRunner {
+        inherit pkgs;
+        nixosConfig = args;
+      };
     };