CODEWITHSUNDEEP
firebasefirebase-realtime-databasegoogle-cloud-functions
Yoann Hercouet
Yoann Hercouet

Reputation: 17996

How to skip a CRON (Cloud Function) execution if already running?

I have the following CRON function inside my index.js file from my Cloud Functions:

// Starts the CRON every 5 minutes in order to get the latest sensors data
exports.cronFunction = functions
  // .region('europe-west1')
  .pubsub.schedule('2,7,12,17,22,27,32,37,42,47,52,57 * * * *')
  .timeZone('Europe/Paris')
  .onRun((context) => {
    const day = moment();
    const db = admin.database();

    console.log('CRON Start for all orders!');
    return updateStatsForDay(db, day, false, true).then(()=>{
      return true;
    }).catch(()=>{
      return false;
    });
});

The problem is that at specific times, the 5 minutes window is too short to finish running the script, so my question is: is there a way to skip the new execution if the previous one is still running?

Upvotes: 0

Views: 265

Answers (1)

Dharmaraj
Dharmaraj

Reputation: 50930

All cloud functions instances are independent of each other and you cannot check if an instance is already active unless you keep track of them yourself. You can store a boolean value in realtime database and check that every time when a function triggers.

exports.cronFunction = functions
  .pubsub.schedule('* * * * *')
  .timeZone('Europe/Paris')
  .onRun(async (context) => {
    // Check if function is already running in database
    const dbRef = admin.database().ref("_status/")
    if ((await dbRef.once("value")).val().myFunction) return {error: "Function already running"}
    // Else update the value to true 
    await dbRef.update({myFunction: true})
    // Process the data
    // Turn the value back to false
    await dbRef.update({myFunction: false})
    // Terminate the function
});

Upvotes: 1

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