add UTM_CONFIG environment variable for VM config

this allows to define a custom nix configuration file
to set the UTM VM configuration parameters. The content
of this nix file is merged with the config.plist of the VM.
The merging is done using json representation.

README.md

@@ -18,6 +18,8 @@ automate as much as possible for a simple automation setup.
 	- adjust ./configuration.nix (atleast set your ssh public key)
 - define an environment variable VM_NAME to name the UTM VM
 	- maybe configure this env var within your project/system setup
+- (optionally) define an environment variable UTM_CONFIG to set UTM VM parameters
+	- fallback to UTM_CONFIG=./utm.config.nix (which is merged using plutil)
 - kickoff the installation process with the following command
 	- assuming your flake is the current directory `.` with config `utm`
 

flake.nix

@@ -60,10 +60,9 @@
         };
         packages.nixosIP = pkgs.writeShellApplication {
           name = "nixosIP";
-          runtimeInputs = [self'.packages.nixosCmd pkgs.gnused];
+          runtimeInputs = [self'.packages.utmConfiguration pkgs.gnused];
           text = ''
-            UTM_DATA_DIR="$HOME/Library/Containers/com.utmapp.UTM/Data/Documents";
+            MAC=$(utmConfiguration mac)
-            MAC=$(sed -ne 's/.*\(..:..:..:..:..:..\).*/\1/p' "$UTM_DATA_DIR/$VM_NAME.utm/config.plist")
             # shellcheck disable=SC2001
             MAC1=$(sed -e 's/0\([[:digit:]]\)/\1/g' <<< "$MAC")
             IP=
@@ -121,12 +120,17 @@
             self'.packages.nixosCmd
             self'.packages.nixosIP
             self'.packages.killUTM
+            self'.packages.utmConfiguration
             inputs'.nixos-anywhere.packages.default
           ];
           text = ''
             set -x
             FLAKE_CONFIG=''${1:-".#utm"}
             shift 1
+
+            # define UTM_CONFIG -- or fallback to provided default
+            : "''${UTM_CONFIG:=${./utm.config.nix}}"
+
             echo "## Check that the provided nixosConfiguration $FLAKE_CONFIG exists"
             nix eval "''${FLAKE_CONFIG/'#'/'#'nixosConfigurations.}.config.system.stateVersion"
 
@@ -146,19 +150,7 @@
             osascript ${./setupVM.osa} "$VM_NAME" "$MAC_ADDR" ${self'.packages.nixosImg}
 
             echo "configure the VM with plutil"
-            UTM_DATA_DIR="$HOME/Library/Containers/com.utmapp.UTM/Data/Documents";
+            utmConfiguration update "$UTM_CONFIG"
-            FOLDER="$UTM_DATA_DIR/$VM_NAME.utm"
-            CFG="$FOLDER"/config.plist
-            plutil -insert "Display.0" -json '{ "HeightPixels": 1200, "PixelsPerInch": 226, "WidthPixels": 1920 }' "$CFG"
-            plutil -replace "Virtualization.Rosetta" -bool true "$CFG"
-            plutil -replace "Virtualization.Keyboard" -bool true "$CFG"
-            plutil -replace "Virtualization.Trackpad" -bool true "$CFG"
-            plutil -replace "Virtualization.Pointer" -bool true "$CFG"
-            plutil -replace "Virtualization.Keybaord" -bool true "$CFG"
-            plutil -replace "Virtualization.ClipboardSharing" -bool true "$CFG"
-            plutil -replace "Virtualization.Audio" -bool true "$CFG"
-            plutil -replace "Virtualization.Balloon" -bool true "$CFG"
-
             echo -e "\n\n## refresh UTMs view of the configuration requires restarting UTM"
             killUTM
 
@@ -189,6 +181,52 @@
             ssh-keygen -R "$(nixosIP)"
           '';
         };
+        packages.utmConfiguration = pkgs.writeShellApplication {
+          name = "utmConfiguration";
+          runtimeInputs = [pkgs.jq];
+          text = ''
+            # INPUTS: VM_NAME
+            UTM_DATA_DIR="$HOME/Library/Containers/com.utmapp.UTM/Data/Documents";
+            VM_FOLDER="$UTM_DATA_DIR/$VM_NAME.utm"
+            PLIST_FILE="$VM_FOLDER"/config.plist
+
+            CMD=$1
+            shift
+
+            case "$CMD" in
+              show)
+                plutil -convert json -o - "$PLIST_FILE" | jq .
+                ;;
+
+              mac)
+                $0 show | jq '.Network[0].MacAddress' -r
+                ;;
+
+              update)
+                NIX_PATCH=$1
+
+                # CREATE TEMPORARY FILES
+                PLIST_JSON=$(mktemp -u)
+                PLIST_JSON_PLIST=$(mktemp -u)
+                JSON_PATCH=$(mktemp -u)
+                trap 'rm $PLIST_JSON $PLIST_JSON_PLIST $JSON_PATCH' EXIT
+
+                # EXECUTE UPDATE
+                nix eval -f "$NIX_PATCH" --json > "$JSON_PATCH"
+                plutil -convert json -o "$PLIST_JSON" "$PLIST_FILE"
+                jq -s 'reduce .[] as $item ({}; . * $item)' "$PLIST_JSON" "$JSON_PATCH" > "$PLIST_JSON_PLIST"
+                plutil -convert binary1 "$PLIST_JSON_PLIST"
+
+                # WRITE UPDATE TO CONFIG
+                cp "$PLIST_JSON_PLIST" "$PLIST_FILE"
+                ;;
+              *)
+                echo "usage: VM_NAME=your-vm $0 show "
+                echo "usage: VM_NAME=your-vm $0 update patch-config.nix"
+                ;;
+            esac
+          '';
+        };
         packages.nixosDeploy = pkgs.writeShellApplication {
           name = "nixosDeploy";
           runtimeInputs = [
@@ -223,7 +261,7 @@
             export UTM_DATA_DIR="$HOME/Library/Containers/com.utmapp.UTM/Data/Documents";
           '';
           packages = builtins.attrValues {
-            inherit (self'.packages) nixosCreate sshNixos utm nixosCmd;
+            inherit (self'.packages) nixosCreate sshNixos utm nixosCmd utmConfiguration nixosIP;
             inherit (pkgs) coreutils nixos-rebuild;
             inherit (inputs'.nixos-anywhere.packages) nixos-anywhere;
           };

utm.config.nix

@@ -0,0 +1,19 @@
+{
+  Display = [
+    {
+      HeightPixels = 1200;
+      WidthPixels = 1920;
+      PixelsPerInch = 226;
+    }
+  ];
+  System = {MemorySize = 4096;};
+  Virtualization = {
+    Audio = true;
+    Balloon = true;
+    ClipboardSharing = true;
+    Keyboard = true;
+    Pointer = true;
+    Rosetta = true;
+    Trackpad = true;
+  };
+}