title: Access Google cloud endpoints on a non-existent version label
body: <p>I have two apps, <code>my_app</code> and <code>my_endpoint_app</code>. I can access <code>my_endpoint_app</code> with any version label in the URL I want and it will automatically route to the default version if it does not match an existing version.</p>
  
  <p>Example:</p>
  
  <p><a href="https://josh-dot-my_endpoint_app.appspot.com/" rel="nofollow">https://josh-dot-my_endpoint_app.appspot.com/</a> will respond with the default version since there is no <code>josh</code> version deployed.</p>
  
  <p>If I try to do the same with a Google Cloud Endpoint service call, I get a Not Found error.</p>
  
  <p>Example:</p>
  
  <p>The unsuccessful <a href="https://josh-dot-my_endpoint_app.appspot.com/_ah/api/myendpoint" rel="nofollow">https://josh-dot-my_endpoint_app.appspot.com/_ah/api/myendpoint</a> vs the working <a href="https://my_endpoint_app.appspot.com/_ah/api/myendpoint" rel="nofollow">https://my_endpoint_app.appspot.com/_ah/api/myendpoint</a></p>
  
  <p>I have a couple of Google AppEngine applications that communicate with each other via Cloud Endpoints. </p>
  
  <p>Under normal usage this is OK because I know the version beforehand and avoid these errors. In our development environment, this falls apart. In order to support feature branches and testing in isolation, we push our code up to appspot using the <code>-V</code> switch of <code>appcfg.py</code>.</p>
  
  <p>Example:
  <code>appcfg.py -A my_app -V josh update .</code></p>
  
  <p>Now I can access my feature branch at <code>https://josh-dot-my_app.appspot.com</code>. In order to support some version label hackery, I dynamically calculate the right endpoint app to call with something like <code>s/my_app/my_endpont_app/g</code> and then make my service calls there. This fails because of the dynamic version label not existing. If I push a version label with that name it completes as expected.</p>
  
  <p>Is there any way to get Cloud Endpoints to answer on non-existent version label hostnames?</p>
  
  <p><strong>Scenarios that I want to support</strong></p>
  
  <ul>
  <li><p><a href="https://my_endpoint_app.appspot.com/_ah/api/myendpoint" rel="nofollow">https://my_endpoint_app.appspot.com/_ah/api/myendpoint</a></p>
  
  <p>Main application URL, routes to default version</p></li>
  <li><p><a href="https://josh-dot-my_endpoint_app.appspot.com/_ah/api/myendpoint" rel="nofollow">https://josh-dot-my_endpoint_app.appspot.com/_ah/api/myendpoint</a></p>
  
  <p>Version does not exist, should route to default version</p></li>
  <li><p><a href="https://new-feature-dot-my_endpoint_app.appspot.com/_ah/api/myendpoint" rel="nofollow">https://new-feature-dot-my_endpoint_app.appspot.com/_ah/api/myendpoint</a></p>
  
  <p>Version new-feature exists, should route to new-feature version so that we can test new code in isolation before merging into the main code branch. This would be internal apis that the current endpoints might make use of without changing what the endpoint accomplishes. (performance improvements, etc)</p></li>
  </ul>