Google App Engine & Python
<p>I got a relatively tough one for you today.</p>

<p>I'm currently taking a Web Development course online and as a first assignment, we're asked to install and use Google App Engine, which runs on Python 2.7 -- I have Python 3.5 installed on my computer. </p>

<p>I tried completing the assignment even though I have the wrong Python version installed. Was able to create a project locally and see it in my browser using <code>localhost:8081</code> -- so far so good.</p>

<p>But for the assignment we need to provide a link, a link that can seemingly only be created once you <em>deploy</em> the project. When I deploy however, this is what I get:</p>

<p>Error in question:</p>

<pre><code>*** Running appcfg.py with the following flags:
    --oauth2_credential_file=~/.appcfg_oauth2_tokens update
05:47 PM Application: hello-udacity; version: 1
05:47 PM Host: appengine.google.com
05:47 PM Starting update of app: hello-udacity, version: 1
05:47 PM Getting current resource limits.
2016-09-29 17:47:57,389 ERROR appcfg.py:2411 An error occurred processing file '': HTTP Error 403: Forbidden Unexpected HTTP status 403. Aborting. 
Error 403: --- begin server output ---
You do not have permission to modify this app (app_id=u's~hello-udacity').
--- end server output ---
If deploy fails you might need to 'rollback' manually.
The "Make Symlinks..." menu option can help with command-line work.
*** appcfg.py has finished with exit code 1 ***
</code></pre>

<p>So my questions are:  </p>

<ol>
<li>What is the root cause of the problem?  </li>
<li>What is the solution?  </li>
<li>If that solution means uninstalling Python3.5 and reinstalling Python 2.7, what is the easiest way for a beginner like me to do it?  </li>
</ol>

<p>If there's anything you think I should know please let me know.</p>

<p>Thanks :)</p>

<p><strong>1&amp;2</strong>: You need to change the application name in the <code>application: hello-udacity</code> line in your <code>app.yaml</code> to match <strong>your real</strong> app name that you obtain when you create your GAE project in the developer console (likely someone else already created an app with that name before which you don't have permissions to modify, which is why your deployment fails).</p>

<p><strong>3</strong>: It's likely to run into problems with python 3.5 on GAE, you <strong>should</strong> install 2.7. But you can do that without uninstalling 3.5, both versions should be able to co-exist on the same machine.</p>

python python-2.7 python-3.x google-app-engine