title: Google data studio User_Pass authorization
body: <p>"Issue description copied..."</p>
  
  <p>I'm building a partner connector, which relies on a user name and password to connect to  database (very similar to the existing Postgres / MySQL connectors provided by Google). In order to verify the credentials, I also need the database host information to be present in addition to username and password and this is the base of my problem. </p>
  
  <p>The Google build connectors conveniently are allowed to collect user credentials and the database related information at the same time. Unfortunately, that doesn't seem to be the case for partner connectors as stated in the requirements </p>
  
  <pre><code>  Point 5 "Use appropriate authentication method in getAuthType(). Do not request credentials via getConfig()." 
  </code></pre>
  
  <p>The authentication itself happens before any other configuration details are known (there is just a dialog for username and password) and there doesn't seem to be a way to request additional information on the authentication screen itself. Once the credentials have been entered, the verification also happens immediately, before the configuration is being shown in the next step. </p>
  
  <p>Once credentials are validated successfully, Datastudio then assumes the schema and data can be requested.This excludes the option of a dummy confirmation, because there doesn't seem to be a way to tell credentials are invalid and need to be changed after checking the other configuration details on the next screen.</p>
  
  <p>That makes me unsure, how to determine valid credentials in my use case as I need to know the variable endpoint to authenticate against. I definitely want to avoid storing any user credentials myself in an external database, because this opens up another can of worms.</p>
  
  <p>Has anyone successfully solved a similar issue before and can provide guidance here?</p>