修复自动备份真实挂载解析（07-27-automatic-offhost-backup）

scripts/run-automatic-backup.sh

@@ -134,8 +134,18 @@ container_env() {
 mount_source() {
   local container_id="$1"
   local destination="$2"
-  docker inspect -f '{{range .Mounts}}{{println .Destination "\t" .Source}}{{end}}' "$container_id" \
-    | awk -F '\t' -v expected="$destination" '$1 == expected { print $2 }'
+  docker inspect -f '{{json .Mounts}}' "$container_id" \
+    | python3 -c '
+import json
+import sys
+
+destination = sys.argv[1]
+mounts = json.load(sys.stdin)
+matches = [mount.get("Source", "") for mount in mounts if mount.get("Destination") == destination]
+if len(matches) != 1 or not matches[0]:
+    raise SystemExit(1)
+print(matches[0])
+' "$destination"
 }
 
 resolve_active_runtime() {