ImportError: No module named flask_restful

Question

I am trying to deploy appengine flex python app but getting the following in Stackdriver log stderr after deployment

  File "/env/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 578, in spawn_worker
    worker.init_process()
  File "/env/local/lib/python2.7/site-packages/gunicorn/workers/base.py", line 126, in init_process
    self.load_wsgi()
  File "/env/local/lib/python2.7/site-packages/gunicorn/workers/base.py", line 135, in load_wsgi
    self.wsgi = self.app.wsgi()
  File "/env/local/lib/python2.7/site-packages/gunicorn/app/base.py", line 67, in wsgi
    self.callable = self.load()
  File "/env/local/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 65, in load
    return self.load_wsgiapp()
  File "/env/local/lib/python2.7/site-packages/gunicorn/app/wsgiapp.py", line 52, in load_wsgiapp
    return util.import_app(self.app_uri)
  File "/env/local/lib/python2.7/site-packages/gunicorn/util.py", line 352, in import_app
    __import__(module)
  File "/home/vmagent/app/my_service/entry_point.py", line 5, in <module>
    import flask_restful as restful
ImportError: No module named flask_restful

entry_point.py in line 5 has

import flask_restful as restful

And my requirement.txt has

Flask-RESTful==0.3.6
gunicorn==19.7.1

Not sure why its still complaining about Flask-Restful

Answer 1

Imports are case sensitive on certain platforms, namely Linux (Windows and Mac may or may not care about case). The package Flask-RESTful isn't all lowercase like most packages (as per PEP 8 recommendation), so import flask_restful as restful will yield an import error unless the proper case is used.