title: AppEngine 500 Server Error after deploy -- error in code?
body: <p>I understand there are many posts already about this error, but my problem does seem unique, at least from my standpoint. Please prove me wrong! I am using Python 2.7, importing jinja2, and a db by way of <code>from google.appengine.ext import db</code>. My other simpler apps that don't import these packages deploy just fine, but this one throws an <code>Error: Server Error</code>. Could this have anything to do with my code, or is this a problem on Google's end? Seems this is a common error these days, but there also seem to be many diagnoses. However, as some of my apps deploy and not others, this is suspicious. Thanks.</p>
  
  <p>--Some extra info--</p>
  
  <p>As I said in my comments, the local run works fine and the deploy throws the server error.</p>
  
  <p>**Log output after local run:</p>
  
  <pre><code>*** Running dev_appserver with the following flags: --admin_console_server= --port=8080
  Python command: /usr/local/bin/python2.7
  WARNING  2013-03-17 03:06:52,527 dev_appserver.py:3578] The datastore file stub is 
  deprecated, and will stop being the default in a future release.
  Append the --use_sqlite flag to use the new SQLite stub.
  
  You can port your existing data using the --port_sqlite_data flag or
  purge your previous test data with --clear_datastore.
  
  WARNING  2013-03-17 03:06:52,550 dev_appserver.py:3682] Could not initialize images API;
  you are likely missing the Python "PIL" module. ImportError: No module named _imaging
  INFO     2013-03-17 03:06:52,572 dev_appserver_multiprocess.py:656] Running application
  dev~app1 on port 8080: http://localhost:8080
  INFO     2013-03-17 03:06:52,572 dev_appserver_multiprocess.py:658] Admin console is
  available at: http://localhost:8080/_ah/admin
  </code></pre>
  
  <p>**Log output after deploy:</p>
  
  <pre><code>*** Running appcfg.py with the following flags:
  --no_cookies --email=***@gmail.com --passin update
  08:02 PM Host: appengine.google.com
  08:02 PM Application: app1; version: 1
  08:02 PM 
  Starting update of app: app1, version: 1
  08:02 PM Getting current resource limits.
  08:02 PM Scanning files on local disk.
  08:02 PM Cloning 1 static file.
  08:02 PM Cloning 4 application files.
  08:02 PM Compilation starting.
  08:02 PM Compilation completed.
  08:02 PM Starting deployment.
  08:02 PM Checking if deployment succeeded.
  08:02 PM Deployment successful.
  08:02 PM Checking if updated app version is serving.
  08:02 PM Completed update of app: app1, version: 1
  Password for ***@gmail.com: 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 0 ***
  </code></pre>
  
  <p>--UPDATE--
  Turns out I had a variable naming error, and when that was cleared up, no more 500 Server Error. I wish the errors thrown were a bit more explanatory, as they usually are besides this particular case. Lesson learned -- if you find yourself in this situation, it is certainly an error in your code. Thanks for your help everyone.</p>