title: Require key file by path in Google Cloud Function
body: <p>I have the functions for Google Cloud Function that needs to require json key file.</p>
  
  <p>For example:</p>
  
  <pre><code>const SERVICE_ACCOUNT_EMAIL = 'your_service_account_email@developer.gserviceaccount.com';
  const SERVICE_ACCOUNT_KEY_FILE = require('./path/to/your/service_account.json');
  
  const jwtClient = new google.auth.JWT(
      SERVICE_ACCOUNT_EMAIL,
      null,
      SERVICE_ACCOUNT_KEY_FILE.private_key,
      ['https://www.googleapis.com/auth/androidpublisher'],
      null
  );
  </code></pre>
  
  <p>How I can get access for SERVICE_ACCOUNT_KEY_FILE? Where should I upload the file and how next do I will find its path?</p>