new build script

.gitignore

@@ -1,4 +1,4 @@
 server-info.txt
 nixos/out
 nixos/error
-virtual-machines/*/result/
+virtual-machines/*/result

nixos/configuration.nix

@@ -206,6 +206,11 @@
   # Init with `incus admin init --minimal`
   virtualisation.incus.enable = true;
 
+  # allow sandboxes to see my temp keys
+  nix.settings.extra-sandbox-paths = [
+    "/run/sops-virtual-key.txt=/run/sops-virtual/virtual-key.txt"
+  ];
+
   networking = {
     hostName = meta.hostname;
     hostId = meta.hostId;

virtual-machines/vm-test/build-image.sh

@@ -1,54 +1,176 @@
 #!/usr/bin/env bash
-set -euo pipefail
+set -Eeuo pipefail
 
 # Usage:
-#   ./build-image.sh <alias> [vmname]
+#   ./build-image.sh <vm-folder> <alias> [vmname]
 #
-# Examples:
+# Example:
-#   ./build-image.sh nixos/custom/vm
+#   ./build-image.sh vm-test nixos/custom/jellybean
-#   ./build-image.sh nixos/custom/my-vm my-vm
+#
+# Run from anywhere; all project operations use virtual-machines/.
 
-if [[ $# -lt 1 || $# -gt 2 ]]; then
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
-    echo "Usage: $0 <alias> [vmname]"
+cd "$SCRIPT_DIR"
-    echo
+
-    echo "  alias   Required Incus image alias"
+if [[ $# -lt 2 || $# -gt 3 ]]; then
-    echo "  vmname  NixOS configuration name (default: vm)"
+    echo "Usage: $0 <vm-folder> <alias> [vmname]"
     exit 1
 fi
 
-ALIAS="$1"
+VM_FOLDER="$1"
-VMNAME="${2:-vm}"
+ALIAS="$2"
+VMNAME="${3:-vm}"
+
+VM_DIR="$SCRIPT_DIR/$VM_FOLDER"
+SOPS_CONFIG="$SCRIPT_DIR/.sops.yaml"
+AGE_DIR="/run/sops-virtual"
+AGE_KEY="$AGE_DIR/virtual-key.txt"
+SANDBOX_KEY="/run/sops-virtual-key.txt"
+
+for cmd in age-keygen sops yq nix incus sudo; do
+    command -v "$cmd" >/dev/null 2>&1 || {
+        echo "Missing required command: $cmd" >&2
+        exit 1
+    }
+done
+
+[[ -d "$VM_DIR" ]] || {
+    echo "VM directory not found: $VM_DIR" >&2
+    exit 1
+}
+
+[[ -f "$VM_DIR/flake.nix" ]] || {
+    echo "No flake.nix found in $VM_DIR" >&2
+    exit 1
+}
+
+[[ -f "$SOPS_CONFIG" ]] || {
+    echo "SOPS config not found: $SOPS_CONFIG" >&2
+    exit 1
+}
+
+[[ -d "$VM_DIR/secrets" ]] || {
+    echo "Secrets directory not found: $VM_DIR/secrets" >&2
+    exit 1
+}
+
+# Refuse to overwrite a key that may belong to another running build.
+if sudo test -e "$AGE_KEY"; then
+    echo "Temporary key already exists: $AGE_KEY" >&2
+    echo "Remove it or investigate the previous build before continuing." >&2
+    exit 1
+fi
+
+SOPS_BACKUP="$(mktemp)"
+AGE_TEMP="$(mktemp)"
+cp -p "$SOPS_CONFIG" "$SOPS_BACKUP"
+
+CLEANED_UP=0
+
+cleanup() {
+    local status=$?
+
+    if [[ "$CLEANED_UP" -eq 1 ]]; then
+        return
+    fi
+    CLEANED_UP=1
+
+    # Restore the repository's original SOPS configuration.
+    cp "$SOPS_BACKUP" "$SOPS_CONFIG"
+    rm -f "$SOPS_BACKUP" "$AGE_TEMP"
+
+    # Remove the temporary private key, even if the build failed.
+    sudo rm -f "$AGE_KEY"
+    sudo rmdir "$AGE_DIR" 2>/dev/null || true
+
+    echo "Temporary age key removed."
+
+    return "$status"
+}
+
+trap cleanup EXIT
+trap 'exit 130' INT
+trap 'exit 143' TERM
+
+echo "Generating temporary age identity..."
+
+age-keygen -o "$AGE_TEMP"
+AGE_PUBLIC_KEY="$(age-keygen -y "$AGE_TEMP")"
+
+# Make the key readable by Nix build users, but not ordinary users.
+sudo install -d -o root -g nixbld -m 0750 "$AGE_DIR"
+sudo install -o root -g nixbld -m 0440 \
+    "$AGE_TEMP" "$AGE_KEY"
+
+# Update age recipients in the SOPS creation rules temporarily.
+# Requires mikefarah/yq v4 and simple comma-separated age fields.
+export AGE_PUBLIC_KEY
+
+if ! yq -e \
+    '.creation_rules | any(.[]; has("age"))' \
+    "$SOPS_CONFIG" >/dev/null; then
+    echo "No creation_rules with an age field found in .sops.yaml" >&2
+    exit 1
+fi
+
+yq -i '
+    (.creation_rules[] | select(has("age")) | .age) |= (
+        split(",")
+        | map(trim)
+        | map(select(. != ""))
+        | . + [strenv(AGE_PUBLIC_KEY)]
+        | unique
+        | join(",")
+    )
+' "$SOPS_CONFIG"
+
+echo "Updating SOPS recipients for secrets in $VM_FOLDER..."
+
+shopt -s nullglob
+SECRET_FILES=("$VM_DIR"/secrets/*)
+shopt -u nullglob
+
+if [[ ${#SECRET_FILES[@]} -eq 0 ]]; then
+    echo "No secret files found in $VM_DIR/secrets" >&2
+    exit 1
+fi
+
+for secret in "${SECRET_FILES[@]}"; do
+    [[ -f "$secret" ]] || continue
+    echo "Updating recipients: ${secret#"$SCRIPT_DIR"/}"
+    sops updatekeys --yes "$secret"
+done
+
+echo "Building VM metadata..."
 
-# Build the NixOS LXC metadata tarball
 TARBALL_DIR="$(nix build \
-    ".#nixosConfigurations.${VMNAME}.config.system.build.metadata" \
+    "./$VM_FOLDER#nixosConfigurations.${VMNAME}.config.system.build.metadata" \
     --print-out-paths)"
 
-# Find the tarball
 TARBALL="$(find "$TARBALL_DIR" -type f -name '*.tar.xz' -print -quit)"
 
 if [[ -z "$TARBALL" ]]; then
-    echo "Could not find a .tar.xz tarball in: $TARBALL_DIR"
+    echo "Could not find a .tar.xz tarball in: $TARBALL_DIR" >&2
     exit 1
 fi
 
 echo "Metadata tarball: $TARBALL"
 
-# Build the QEMU disk image
+echo "Building QEMU disk image..."
+
 QCOW2_DIR="$(nix build \
-    ".#nixosConfigurations.${VMNAME}.config.system.build.qemuImage" \
+    "./$VM_FOLDER#nixosConfigurations.${VMNAME}.config.system.build.qemuImage" \
     --print-out-paths)"
 
 QCOW2="$QCOW2_DIR/nixos.qcow2"
 
 if [[ ! -f "$QCOW2" ]]; then
-    echo "QEMU image not found: $QCOW2"
+    echo "QEMU image not found: $QCOW2" >&2
     exit 1
 fi
 
-echo "Found QEMU image: $QCOW2"
+echo "QEMU image: $QCOW2"
 
-echo
 echo "Importing image into Incus..."
 
 incus image import \
@@ -56,6 +178,5 @@ incus image import \
     "$TARBALL" \
     "$QCOW2"
 
-echo
 echo "Successfully imported image: $ALIAS"
 

virtual-machines/vm-test/flake.nix

@@ -27,9 +27,7 @@
             pkgs.runCommand "sops-decrypt-${filename}"
               {
                 # Use special separate injectable key that can only decrypt these dummy secrets
-                SOPS_AGE_KEY_FILE = "/home/roy/.config/sops/age/virtual-key.txt";
+                SOPS_AGE_KEY_FILE = "/run/sops-virtual-key.txt";
-
-                __noChroot = true;
               }
               ''
                 ${pkgs.sops}/bin/sops -d ${./secrets}/${filename} > $out