Google Apps Script Calendar Service: How to avoid exceeding maximum execution time?

Question

I need to edit a few hundred or even a few thousand calendar events through Google Apps Script. It is about just minor changes to title ( event.setTitle() ) and description ( event.setDescription() ), nothing fancy. Trying with about 600 events the maximum execution time of 360 seconds is already exceeded.

var cal = CalendarApp.getCalendarById("Calendar Id");
var startTime = new Date(1850, 0, 1);
var endTime = new Date(2100, 0, 1);
var events = cal.getEvents(startTime, endTime);
for (var i = 0; i < events.length; i++) {
  events[i].setTitle(events[i].getTitle() + " something");
  events[i].setDescription(events[i].getDescription() + " something else");
}

How to process the events in several chunks successively?

Answer 1

Answer:

Use PropertiesService to save where you got to so you can continue where you left of on next run.

Code:

You can use a PropertiesService key value pair to save the value of the count through events[] :

function renameEvents() {
  var cal = CalendarApp.getCalendarById("Calendar Id");
  var startTime = new Date(1850, 0, 1);
  var endTime = new Date(2100, 0, 1);
  var events = cal.getEvents(startTime, endTime);
  var sp = PropertiesService.getScriptProperties();
  if (!(sp.getProperty("count")) || sp.getProperty("count") == 0) {
    var count = 0;
  else if ((sp.getProperty("count") > 0) {
    var count = sp.getProperty("count");
  }

  for (var i = count; i < events.length; i++) {
    events[i].setTitle(events[i].getTitle() + " something");
    events[i].setDescription(events[i].getDescription() + " something else");
    sp.setProperty("count", i)
  }
}

It'll make the script a little slower, but each time you run it it'll continue along the calendar events from where the last one stopped.

I hope this is helpful to you!

References:

• Class PropertiesService | Apps Script | Google Developers

Answer 2

I have previously used something similar to the following:

At the start of each loop check that a sufficient buffer time is available to complete the loop.

Update the buffer time whenever a single loop time exceeds it.

Use the PropertiesService to store both the buffer and the last index.

var cal = CalendarApp.getCalendarById("Calendar Id");
var startTime = new Date(1850, 0, 1);
var endTime = new Date(2100, 0, 1);
var events = cal.getEvents(startTime, endTime);
var ps = PropertiesService.getScriptProperties();
var startIndex = ps.getProperty('lastIndex') || 0;
var buffer = ps.getProperty('buffer') || 100;

var startTime = new Date();
var maxTime = 1000*60*6; //6 mins


for (var i = startIndex; i < events.length; i++) {
  var loopStart = new Date()
  if (loopStart - startTime > (maxTime-buffer) ) {
     ps.setProperty('lastIndex', i);
     break;
  }
  events[i].setTitle(events[i].getTitle() + " something");
  events[i].setDescription(events[i].getDescription() + " something else");
  var loopTime = new Date() - loopStart;
  if (loopTime  > buffer ) buffer = loopTime * 1.5
}

ps.setProperty('buffer',buffer)