How to wait for async actions inside AWS Lambda?

Question

I am trying to process uploaded file in S3. Since getObject is asyncronous main function ends before processing is done, and AWS kills lambda in 3-4 seconds

Answer 1

I think your lambda function should end with a context.done() call. For instance, try adding it this way:

s3.getObject(params, function(err, data) {
    if (err) {
         ...
        context.done("Error: " + err.stack);
    } else {
        processFile(data.Body.toString(), 0);
        console.log("ok");
        context.done(null, "success");
    }
});