Inifinite loop on updating Google Calendar event by script (trigger issue)

Question

I wrote a script to add tags and modify color of Google Calendar events. The script :

• select some events based on date range
• apply some rules on the selected events

The script itself work just fine and is launched on a timely basis. However, if I set up a trigger based on the update event trigger, then :

• script will launch OK
• events are updated
• each event updated triggers a new launch of the script => Infinite Loop.

There has to be something that I do not understand about this trigger. How to prevent thos multiples executions ? Basically, I would like to "disable" the trigger while the script is running.

Many thanks,

Nico.

Tried :

• using tags to record the events already processsed, but I still have the issue if I force the update
• implementing this function

The code is like :

var hasLock = new Boolean(false)

function onCalendarEvent() { 
  // lock to prevent multiple executions of script
  if(DEBUG) {
    console.log("Event based laucnh. Lock is " + hasLock)
  }
  if (hasLock == false) {
    hasLock = true
    if(DEBUG) { console.log("Calling function") }    
    colorizeEvents(0) 
    hasLock = false
  }
}

function onCalendarEvent() {
 // do stuff : select events and update them
}