functions: add "filesystem is not persistent" note
@@ -31,6 +31,10 @@ func UploadFile(w http.ResponseWriter, r *http.Request) {
// The whole request body is parsed and up to a total of maxMemory bytes of
// its file parts are stored in memory, with the remainder stored on
// disk in temporary files.
+
+ // Note that any files saved during a particular invocation may not
+ // persist after the current invocation completes; persistent files
+ // should be stored elsewhere, such as in a Cloud Storage bucket.
if err := r.ParseMultipartForm(maxMemory); err != nil {
http.Error(w, "Unable to parse form", http.StatusBadRequest)
log.Printf("Error parsing form: %v", err)
