title: Get status of asynchronous (InvocationType=Event) AWS lambda execution
body: <p>I am creating an AWS step function where one of the step, let's call it step X, starts a variable number of lambdas. Since these lambda functions are long (they take between 1 and 10 minutes each to complete), I don't want to wait for them in step X. I would be spending money just for waiting. I therefore start them with <code>InvocationType=Event</code> so that they all run asynchronously and in parallel.</p>
  
  <p>Once step X is done starting all these lambdas, I want my step function to wait for all these asynchronous functions to complete. So, a little like described <a href="https://docs.aws.amazon.com/step-functions/latest/dg/sample-project-job-poller.html" rel="nofollow noreferrer">here</a>, I would create some kind of while loop in my step function. This loop would wait until all my asynchronous invocations have completed.</p>
  
  <p>So the problem is: is it possible to query for the status of an AWS lambda that was started with <code>InvocationType=Event</code>?</p>
  
  <p>If it is not possible, I would need my lambdas to persist their status somewhere so that I can poll this status. I would like to avoid this strategy since it does not cover problems that occur outside of my lambda (ex: out of memory, throttling exceptions, etc.)</p>