title: Where to save service account key file for Google Cloud Composer connection setup?
body: <p>I am trying to setup a Google Cloud Platform connection in Google Cloud Composer using the service account key. So I created a GCS bucket and put the service account key file in the bucket. The key is stored in JSON. In the keyfile path field I specified a GCS bucket, and in the keyfile JSON field I specified the file name. The scopes is <a href="https://www.googleapis.com/auth/cloud-platform" rel="noreferrer">https://www.googleapis.com/auth/cloud-platform</a>.</p>
  
  <p>When trying to use this connection to start a Dataproc cluster, I got the error that JSON file can not be found.</p>
  
  <p>Looking at the error message, the code tries to parse the file using:
  <code>with open(filename, 'r') as file_obj</code> which obviously won't work with a GCS bucket path.</p>
  
  <p>So my question is, where should I put this service account key file if it can not be put in a GCS path?</p>