So lately I've been having problems getting App Engine to start locally and actually run my apps.

The problem was I was getting the following error:

No module named google.appengine.dist27.threading  

Which can't be good, right ...

So had to look around a bit and found a few tricks that can find what's wrong to get you back on App Engine.

First start Python in verbose mode with:

python -vvvvv  

This will show you all the locations of imports happening.

So when you run:

import google  

you'll see a big list of files being loaded where you'll be looking for /Applications/

If you can't find this, it means some other package is overriding that namespace.

In my case I saw:

... <lots of output, I'm not adding to save space ...>
import google # loaded from Zip /Library/Python/2.7/site-packages/protobuf-3.0.0_alpha_1-py2.7.egg/google/__init__.pyc  

Which means that my Python instance is trying to load the google namespace from the protobuf package. Sigh ok, so I do fix this?

Easy actually, use virtualenv. I should have been probably been using it anyway :\

Run the following in your apps folder with the app.yaml file:

source bin/activate  


You'll notice an environment was created and you'll terminal will now show the name of the folder this is in. If you try to run the dev server again all should be good! .  

To exit the context of your environment run:


and done.

Enjoy, this took me a while to figure out so hopefully this helps a few people.

If I missed something let me know in the comments below.