title: Is it possible to access Google Play Game Services API with service account?
body: <p>I've created the game thru Google Play Developer Console (it is <code>ready for testing</code>, but not published yet). </p>
  
  <p>Two service accounts are added there as testers - <code>myappid@appspot.gserviceaccount.com</code> (Google App Engine service account) and <code>64436212345-enq9gkd1abcdefghjec2kha39je5ojsc@developer.gserviceaccount.com</code> (manually created service account, it was created before an access to Google Play Game Services API was given). First one is used for production GAE environment, second one is for development environment (run with <code>--appidentity_email_address</code>). Both accounts work well with Google Analytics API.</p>
  
  <p>Now I try to use these accounts to work with Google Play Game Services API.</p>
  
  <p>The following code is used for authorization and works fine:</p>
  
  <pre><code>credentials = AppAssertionCredentials(scope=['https://www.googleapis.com/auth/games', 'https://www.googleapis.com/auth/plus.login'])
  http = credentials.authorize(httplib2.Http(memcache))
  </code></pre>
  
  <p>But I am getting an error when trying to access achievements definition (also tried to get application metadata - got the same issue):</p>
  
  <pre><code>response = service.achievementDefinitions().list().execute()
  </code></pre>
  
  <p>In development environment I get </p>
  
  <pre><code>&lt;HttpError 404 when requesting https://www.googleapis.com/games/v1/achievements?alt=json returned "The requested application with ID 64436212345 was not found."&gt;
  </code></pre>
  
  <p>and in production:</p>
  
  <pre><code>&lt;HttpError 500 when requesting https://www.googleapis.com/games/v1/achievements?alt=json returned ""&gt;
  </code></pre>
  
  <p>What is wrong there? Are service accounts supported by Google Play Services API?</p>
  
  <p><strong>Upd.</strong> Further analysis showed that 64436212345 is an ID of my GAE application, when an ID of my Google Play application is 760943112345. </p>
  
  <p>So, I went to Google Developer Console for application 760943112345 and added <code>64436212345-enq9gkd1abcdefghjec2kha39je5ojsc@developer.gserviceaccount.com</code> and <code>myappid@appspot.gserviceaccount.com</code> as the member their. It didn't help. </p>
  
  <p>Then I generated new service account ID there and run GAE locally with this service account. In result, I've started to get </p>
  
  <pre><code>&lt;HttpError 401 when requesting https://www.googleapis.com/games/v1/applications/760943112345?alt=json returned "User has not completed registration."&gt;
  </code></pre>
  
  <p>Of course, my service account doesn't have Google+ profile.</p>