feat(build): standardize in-container update backup recovery

Auto-restore on update failure via create_backup ERR trap and clear backup stores after successful updates inside the LXC start() flow.

Co-authored-by: Cursor <cursoragent@cursor.com>

misc/build.func

@@ -1075,7 +1075,7 @@ load_vars_file() {
     var_gateway var_hostname var_ipv6_method var_mac var_mknod var_mount_fs var_mtu
     var_net var_nesting var_ns var_os var_protection var_pw var_ram var_tags var_timezone var_tun var_unprivileged
     var_verbose var_version var_vlan var_ssh var_ssh_authorized_key var_container_storage var_template_storage var_searchdomain
-    var_post_install var_vzdump_after_install var_vzdump_storage
+    var_post_install
   )
 
   # Whitelist check helper
@@ -1250,20 +1250,6 @@ load_vars_file() {
             continue
           fi
           ;;
-        var_vzdump_after_install)
-          if [[ "$var_val" != "yes" && "$var_val" != "no" ]]; then
-            msg_warn "Invalid vzdump_after_install '$var_val' in $file (must be yes/no), ignoring"
-            continue
-          fi
-          ;;
-        var_vzdump_storage)
-          local _vz_storage_status
-          _vz_storage_status=$(pvesm status 2>/dev/null | awk -v s="$var_val" '$1 == s { print $3 }')
-          if [[ -n "$var_val" && -z "$_vz_storage_status" ]]; then
-            msg_warn "Storage '$var_val' from $file not found on this node, ignoring"
-            continue
-          fi
-          ;;
         var_container_storage | var_template_storage)
           # Validate that the storage exists and is active on the current node
           local _storage_status
@@ -1307,7 +1293,7 @@ default_var_settings() {
     var_gateway var_hostname var_ipv6_method var_mac var_mknod var_mount_fs var_mtu
     var_net var_nesting var_ns var_os var_protection var_pw var_ram var_tags var_timezone var_tun var_unprivileged
     var_verbose var_version var_vlan var_ssh var_ssh_authorized_key var_container_storage var_template_storage
-    var_post_install var_vzdump_after_install var_vzdump_storage
+    var_post_install
   )
 
   # Snapshot: environment variables (highest precedence)
@@ -1408,10 +1394,6 @@ var_verbose=no
 # Runs ON THE HOST after the container is fully provisioned.
 # Available env vars: APP, NSAPP, CTID, IP, HN, STORAGE, BRG
 # var_post_install=/opt/post-install/myhook.sh
-
-# Optional vzdump backup after successful install (Proxmox host)
-# var_vzdump_after_install=yes
-# var_vzdump_storage=local
 EOF
 
     # Now choose storages (always prompt unless just one exists)
@@ -1490,7 +1472,7 @@ if ! declare -p VAR_WHITELIST >/dev/null 2>&1; then
     var_gateway var_hostname var_ipv6_method var_mac var_mknod var_mount_fs var_mtu
     var_net var_nesting var_ns var_os var_protection var_pw var_ram var_tags var_timezone var_tun var_unprivileged
     var_verbose var_version var_vlan var_ssh var_ssh_authorized_key var_container_storage var_template_storage var_searchdomain
-    var_post_install var_vzdump_after_install var_vzdump_storage
+    var_post_install
   )
 fi
 
@@ -1704,8 +1686,6 @@ _build_current_app_vars_tmp() {
     [ -n "$_tpl_storage" ] && echo "var_template_storage=$(_sanitize_value "$_tpl_storage")"
     [ -n "$_ct_storage" ] && echo "var_container_storage=$(_sanitize_value "$_ct_storage")"
     [ -n "${var_post_install:-}" ] && echo "var_post_install=$(_sanitize_value "${var_post_install}")"
-    [ -n "${var_vzdump_after_install:-}" ] && echo "var_vzdump_after_install=$(_sanitize_value "${var_vzdump_after_install}")"
-    [ -n "${var_vzdump_storage:-}" ] && echo "var_vzdump_storage=$(_sanitize_value "${var_vzdump_storage}")"
   } >"$tmpf"
 
   echo "$tmpf"
@@ -1850,7 +1830,7 @@ advanced_settings() {
     TAGS="community-script${var_tags:+;${var_tags}}"
   fi
   local STEP=1
-  local MAX_STEP=30
+  local MAX_STEP=29
 
   # Store values for back navigation - inherit from var_* app defaults
   local _ct_type="${var_unprivileged:-1}"
@@ -1885,8 +1865,6 @@ advanced_settings() {
   local _mount_fs="${var_mount_fs:-}"
   local _protect_ct="${var_protection:-no}"
   local _post_install="${var_post_install:-}"
-  local _vzdump="${var_vzdump_after_install:-no}"
-  local _vzdump_storage="${var_vzdump_storage:-}"
 
   # Detect host timezone for default (if not set via var_timezone)
   local _host_timezone=""
@@ -2796,58 +2774,9 @@ Leave empty to skip."
       ;;
 
     # ═══════════════════════════════════════════════════════════════════════════
-    # STEP 29: Optional vzdump backup after install
+    # STEP 29: Verbose Mode & Confirmation
     # ═══════════════════════════════════════════════════════════════════════════
     29)
-      local vzdump_default_flag="--defaultno"
-      [[ "$_vzdump" == "yes" ]] && vzdump_default_flag=""
-
-      if whiptail --backtitle "Proxmox VE Helper Scripts [Step $STEP/$MAX_STEP]" \
-        --title "POST-INSTALL VZDUMP" \
-        --ok-button "Next" --cancel-button "Back" \
-        $vzdump_default_flag \
-        --yesno "\nCreate a vzdump backup after successful install?\n\nRuns on the Proxmox host once the container is ready.\n\n(App default: ${var_vzdump_after_install:-no})" 14 62; then
-        _vzdump="yes"
-        local _storages _menu_items=() _s
-        _storages=$(awk '
-/^[a-z]+:/ { if (name != "") { if (has_backup || (!has_content && type == "dir")) print name }
-  split($0,a,":"); type=a[1]; name=a[2]; gsub(/^[ \t]+|[ \t]+$/, "", name); has_content=0; has_backup=0 }
-/^[ \t]*content/ { has_content=1; if ($0 ~ /backup/) has_backup=1 }
-END { if (name != "") { if (has_backup || (!has_content && type == "dir")) print name } }
-' /etc/pve/storage.cfg 2>/dev/null)
-        if [[ -n "$_storages" ]]; then
-          while IFS= read -r _s; do
-            [[ -n "$_s" ]] && _menu_items+=("$_s" " ")
-          done <<<"$_storages"
-          if result=$(whiptail --backtitle "Proxmox VE Helper Scripts [Step $STEP/$MAX_STEP]" \
-            --title "VZDUMP STORAGE" \
-            --ok-button "Next" --cancel-button "Back" \
-            --menu "\nSelect backup storage:" 16 58 8 \
-            "${_menu_items[@]}" \
-            3>&1 1>&2 2>&3); then
-            _vzdump_storage="$result"
-          fi
-        else
-          whiptail --msgbox "No backup-capable storage found.\n\nConfigure storage with 'backup' content in Proxmox first." 10 58
-          _vzdump="no"
-          _vzdump_storage=""
-        fi
-      else
-        if [ $? -eq 1 ]; then
-          _vzdump="no"
-          _vzdump_storage=""
-        else
-          ((STEP--))
-          continue
-        fi
-      fi
-      ((STEP++))
-      ;;
-
-    # ═══════════════════════════════════════════════════════════════════════════
-    # STEP 30: Verbose Mode & Confirmation
-    # ═══════════════════════════════════════════════════════════════════════════
-    30)
       local verbose_default_flag="--defaultno"
       [[ "$_verbose" == "yes" ]] && verbose_default_flag=""
 
@@ -2949,8 +2878,6 @@ Advanced:
   APT_CACHER_IP="$_apt_cacher_ip"
   VERBOSE="$_verbose"
   var_post_install="$_post_install"
-  var_vzdump_after_install="$_vzdump"
-  var_vzdump_storage="$_vzdump_storage"
 
   # Update var_* based on user choice (for functions that check these)
   var_gpu="$_enable_gpu"
@@ -3765,6 +3692,28 @@ runtime_script_status_guard() {
   return 0
 }
 
+# ------------------------------------------------------------------------------
+# _run_update_script()
+#
+# - Runs update_script inside the LXC with standardized backup recovery
+# - create_backup() arms an ERR trap; successful updates clear the backup store
+# - Works even when update_script ends with exit (EXIT trap)
+# ------------------------------------------------------------------------------
+_run_update_script() {
+  local _update_rc=0
+  _on_update_script_exit() {
+    local _exit_rc=$?
+    trap - EXIT
+    if [[ $_exit_rc -eq 0 ]] && declare -f clear_update_backup &>/dev/null; then
+      clear_update_backup
+    fi
+    exit "$_exit_rc"
+  }
+  trap '_on_update_script_exit' EXIT
+  update_script || _update_rc=$?
+  return "$_update_rc"
+}
+
 # ------------------------------------------------------------------------------
 # start()
 #
@@ -3786,7 +3735,7 @@ start() {
     ensure_profile_loaded
     get_lxc_ip
     runtime_script_status_guard || return 0
-    update_script
+    _run_update_script
     run_addon_updates
     update_motd_ip
     cleanup_lxc
@@ -3797,7 +3746,7 @@ start() {
     ensure_profile_loaded
     get_lxc_ip
     runtime_script_status_guard || return 0
-    update_script
+    _run_update_script
     run_addon_updates
     update_motd_ip
     cleanup_lxc
@@ -3827,7 +3776,7 @@ start() {
     ensure_profile_loaded
     get_lxc_ip
     runtime_script_status_guard || return 0
-    update_script
+    _run_update_script
     run_addon_updates
     update_motd_ip
     cleanup_lxc
@@ -6658,26 +6607,6 @@ create_lxc_container() {
 # SECTION 9: POST-INSTALLATION & FINALIZATION
 # ==============================================================================
 
-# ------------------------------------------------------------------------------
-# _run_post_install_vzdump()
-#
-# - Optional vzdump on the Proxmox host after a successful install
-# - Controlled by var_vzdump_after_install / var_vzdump_storage
-# ------------------------------------------------------------------------------
-_run_post_install_vzdump() {
-  [[ "${var_vzdump_after_install:-no}" != "yes" ]] && return 0
-  [[ -z "${CTID:-}" ]] && return 0
-
-  local storage="${var_vzdump_storage:-${CONTAINER_STORAGE:-local}}"
-  msg_info "Creating post-install vzdump backup (CT ${CTID} → ${storage})"
-  if vzdump "$CTID" --mode snapshot --compress zstd --storage "$storage" \
-    --notes-template "community-scripts post-install - ${APP:-LXC}" >>"${BUILD_LOG:-/dev/null}" 2>&1; then
-    msg_ok "Post-install vzdump created on ${storage}"
-  else
-    msg_warn "Post-install vzdump failed (storage: ${storage})"
-  fi
-}
-
 # ------------------------------------------------------------------------------
 # description()
 #
@@ -6776,8 +6705,6 @@ EOF
     fi
   fi
 
-  _run_post_install_vzdump
-
   INSTALL_COMPLETE=true
   post_update_to_api "done" "none"
 }

misc/tools.func

@@ -1162,6 +1162,7 @@ create_backup() {
 
   if [[ -f "$manifest" ]]; then
     msg_ok "Existing backup found at ${store}, skipping backup"
+    trap '_restore_update_backup_on_error' ERR
     return 0
   fi
 
@@ -1186,6 +1187,24 @@ create_backup() {
     echo "$path" >>"$manifest"
   done
   msg_ok "Backed up data to ${store}"
+  trap '_restore_update_backup_on_error' ERR
+}
+
+_restore_update_backup_on_error() {
+  local _err=$?
+  trap - ERR
+  if [[ -f "${BACKUP_DIR:-/opt/${NSAPP:-app}.backup}/.manifest" ]]; then
+    msg_error "Update failed (exit ${_err}) – restoring backup"
+    restore_backup
+  fi
+  exit "${_err:-1}"
+}
+
+clear_update_backup() {
+  local store="${BACKUP_DIR:-/opt/${NSAPP:-app}.backup}"
+  [[ -d "$store" ]] || return 0
+  rm -rf "$store"
+  trap - ERR
 }
 
 restore_backup() {
@@ -1208,6 +1227,7 @@ restore_backup() {
     cp -a "$src" "$path"
   done <"$manifest"
   rm -rf "$store"
+  trap - ERR
   msg_ok "Restored data"
 }
 

tools/ci/check-update-backup.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# Copyright (c) 2021-2026 community-scripts ORG
+# License: MIT
+#
+# Flags ct/*.sh update_script blocks that mutate config/data destructively
+# without calling create_backup. Used in CI / local review before merge.
+
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+CT_DIR="${ROOT}/ct"
+FAIL=0
+CHECKED=0
+FLAGGED=0
+
+check_file() {
+  local file="$1"
+  local base content block
+  base="$(basename "$file")"
+  content="$(<"$file")"
+  [[ "$content" == *"function update_script"* ]] || return 0
+  CHECKED=$((CHECKED + 1))
+
+  block="$(python3 - "$file" <<'PY'
+import re, sys
+text = open(sys.argv[1]).read()
+m = re.search(r'function update_script\(\).*?(?=^function |\Z)', text, re.S | re.M)
+print(m.group() if m else "")
+PY
+)"
+
+  [[ -n "$block" ]] || return 0
+  [[ "$block" == *"create_backup"* ]] && return 0
+
+  if echo "$block" | grep -qE 'sed -i|\.env|settings\.(py|json)|config\.(json|yml|yaml)|/etc/[^ ]+\.(conf|env)'; then
+    if echo "$block" | grep -qE 'rm -rf|find .* -delete|mv .*\.(bak|old)'; then
+      echo "MISSING create_backup: ct/${base}"
+      FLAGGED=$((FLAGGED + 1))
+      FAIL=1
+    fi
+  fi
+}
+
+for f in "$CT_DIR"/*.sh; do
+  [[ -f "$f" ]] || continue
+  check_file "$f"
+done
+
+echo "Checked ${CHECKED} update scripts, flagged ${FLAGGED} without create_backup"
+exit "$FAIL"