Interface Lock

A representation of a mutual-exclusion lock.

This class allows scripts to make sure that only one instance of the script is executing a given section of code at a time. This is particularly useful for callbacks and triggers, where a user action may cause changes to a shared resource and you want to ensure that aren't collisions.

The following examples shows how to use a lock in a form submit handler.

// Generates a unique ticket number for every form submission.
function onFormSubmit(e) {
  var targetCell = e.range.offset(0, e.range.getNumColumns(), 1, 1);

  // Get a script lock, because we're about to modify a shared resource.
  var lock = LockService.getScriptLock();
  // Wait for up to 30 seconds for other processes to finish.
  lock.waitLock(30000);

  var ticketNumber = Number(ScriptProperties.getProperty('lastTicketNumber')) + 1;
  ScriptProperties.setProperty('lastTicketNumber', ticketNumber);

  // Release the lock so that other processes can continue.
  lock.releaseLock();

  targetCell.setValue(ticketNumber);
}

lastTicketNumber ScriptProperties