Installing modules in Google App Engine for Python

Case 1. Third-party modules

If you want to installing third-party libraries (with no C extensions) which are not contained on GAE Running environment like WTForms:

$ cd myapp
$ virtualenv venv
$ source venv/bin/activate
(venv) $ mkdir lib
(venv) $ pip install -t lib -r requirements.txt

or

(venv) $ pip install -t lib WTForms WTForms-Appengine

Case 2. Modules that built-in Google App Engine

Else that libraries are contained in GAE running environment, then define that libraries by “libraries section” in app.yaml like so:

libraries:
- name: jinja2
  version: latest