การใช้ lock

try {
     var folder = DriveApp.getFolderById('xxx');//ไอดีโฟลเดอร์
     var date = Utilities.formatDate(new Date(),'GMT+7','dd/MM/yyyy')
    var contentType = data.substring(5, data.indexOf(';')),
      bytes = Utilities.base64Decode(data.substr(data.indexOf('base64,') + 7)),
      blob = Utilities.newBlob(bytes, contentType, file),
      file = folder.createFolder([name,date].join(" ")).createFile(blob),
      filelink = file.getUrl();
    var lock = LockService.getPublicLock();
    lock.waitLock(30000);

    var doc = SpreadsheetApp.openById('xxx');
    var sheet = doc.getSheetByName('ชีต1');
    sheet.appendRow([new Date(),name,filelink])
    var headRow = 1;
    var headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];
    var nextRow = sheet.getLastRow() + 1;
    var row = [];
    for (i in headers) {
      if (headers[i] == "วันที่") {
        row.push(new Date());
      } else if (headers[i] == "ชื่อ สกุล") {
        row.push(name);
      } else if (headers[i] == "โรงเรียน") {
        row.push(school);
      } else if (headers[i] == "อีเมล") {
        row.push(email);
      } else if (headers[i] == "เบอร์โทร") {
        row.push('0'+tel.toString())
      } else if (headers[i] == "ลิ้งค์ไฟล์") {
        row.push(filelink);
      }

    }
    sheet.getRange(nextRow, 1, 1, row.length).setValues([row]);
    return "success";

  } catch (f) {
    return f.toString();
  } finally {
    lock.releaseLock();
  }