[IMP] add external command verification at startup

Add check_required_commands() function to verify that all required
external tools are available before the script begins execution:
- docker: Container runtime
- compose: Docker compose wrapper (0k-scripts)
- sudo: Required for filestore operations

Benefits:
- Fails fast with a clear error message listing missing commands
- Prevents cryptic 'command not found' errors mid-execution
- Documents script dependencies explicitly
- Called immediately after argument validation in upgrade.sh

lib/common.sh

@@ -9,6 +9,20 @@ set -euo pipefail
 readonly DATASTORE_PATH="/srv/datastore/data"
 readonly FILESTORE_SUBPATH="var/lib/odoo/filestore"
 
+check_required_commands() {
+    local missing=()
+    for cmd in docker compose sudo; do
+        if ! command -v "$cmd" &>/dev/null; then
+            missing+=("$cmd")
+        fi
+    done
+    if [[ ${#missing[@]} -gt 0 ]]; then
+        log_error "Required commands not found: ${missing[*]}"
+        log_error "Please install them before running this script."
+        exit 1
+    fi
+}
+
 log_info()  { printf "[INFO]  %s\n" "$*"; }
 log_warn()  { printf "[WARN]  %s\n" "$*" >&2; }
 log_error() { printf "[ERROR] %s\n" "$*" >&2; }
@@ -64,4 +78,5 @@ exec_python_script_in_odoo_shell() {
 
 export DATASTORE_PATH FILESTORE_SUBPATH
 export -f log_info log_warn log_error log_step
+export -f check_required_commands
 export -f query_postgres_container copy_database copy_filestore exec_python_script_in_odoo_shell

upgrade.sh

@@ -29,6 +29,8 @@ if [[ $# -lt 4 ]]; then
     usage
 fi
 
+check_required_commands
+
 readonly ORIGIN_VERSION="$1"
 readonly FINAL_VERSION="$2"
 readonly ORIGIN_DB_NAME="$3"