Windows local appengine usage: oauth2client ImportError - python-2.7

Question

I m working with App Engine Standard, developing a Python backend service and, at some point, I told myself:
"Hey why don't you try out and run the server locally while using the remote Datastore"
I can run this code locally but I couldn't figure out why the remote_api_stub throws the error :
" File "C:\Program Files (x86)\Google\Cloud
SDK\google-cloud-sdk\platform\google_appengine\google\appengine\ext\remote_api\remote_api_stub.py",
line 1003, in ConfigureRemoteApiForOAuth 'oauth2client module: %s' %
e)
ImportError: Use of OAuth credentials requires the oauth2client
module: No module named oauth2client"
Even though, according to pip, I got the oauth2client installed already (I see that when I run pip install --upgrade oauth2client
Thank you in advance for your help
EDIT:
My issue is not a duplicate of ImportError: No module named oauth2client. I yet did install google api client in the lib folder and made sure the "appengine_config.py" file was in its place with the necessary lines.
It still didn't resolve my issue, so I'm going to give more details about it !
Here is my main.py (taking care of the default service of GAE) or at least a degreased version of what it is:
import os
import datetime
import dev_appserver
from google.appengine.ext.remote_api import remote_api_stub
from google.appengine.api import apiproxy_stub_map
dev_appserver.fix_sys_path()
local_urlfetch_stub = apiproxy_stub_map.apiproxy.GetStub('urlfetch')
def configure_remote_api_dev_safe (host):
if not os.getenv('SERVER_SOFTWARE', '').startswith('Google App Engine/'):
logging.info("running on local server")
remote_api_stub.ConfigureRemoteApiForOAuth(host, '/_ah/remote_api')
apiproxy_stub_map.apiproxy.ReplaceStub('urlfetch', local_urlfetch_stub)
else:
logging.info("running on remote server")
def configure_remote_api_dev_unsafe (host):
if not os.getenv('SERVER_SOFTWARE', '').startswith('Google App Engine/'):
remote_api_stub.ConfigureRemoteApiForOAuth(host, '/_ah/remote_api')
else:
logging.info("running on remote server")
class Main(webapp2.RequestHandler):
def post(self):
configure_remote_api_dev_safe ('{}.appspot.com'.format(app))
test = Test(createdAt=datetime.datetime.utcnow())
test.put()
self.response.write("done")
app = ndb.toplevel(webapp2.WSGIApplication({('/', Main)}, debug=True))
And I get this error when I request the default service:
PATH_TO_PROJECT_FOLDER>dev_appserver.py PATH_TO_PROJECT_FOLDER
INFO 2018-07-20 10:45:17,740 devappserver2.py:178] Skipping SDK update check.
INFO 2018-07-20 10:45:18,117 api_server.py:274] Starting API server at: http://localhost:53725
INFO 2018-07-20 10:45:18,151 dispatcher.py:270] Starting module "default" running at: http://localhost:8080
INFO 2018-07-20 10:45:18,153 admin_server.py:152] Starting admin server at: http://localhost:8000
INFO 2018-07-20 10:46:57,006 instance.py:294] Instance PID: 5940
WARNING 2018-07-20 08:46:57,565 sandbox.py:1086] The module _winreg is whitelisted for local dev only. If your application relies on _winreg, it is likely that it will not function properly in production.
INFO 2018-07-20 08:46:57,757 main.py:35] running on local server
ERROR 2018-07-20 08:46:57,760 webapp2.py:1528] Use of OAuth credentials requires the oauth2client module: No module named oauth2client
Traceback (most recent call last):
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1511, in __call__
rv = self.handle_exception(request, response, e)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1505, in __call__
rv = self.router.dispatch(request, response)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1253, in default_dispatcher
return route.handler_adapter(request, response)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1077, in __call__
return handler.dispatch()
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 547, in dispatch
return self.handle_exception(e, self.app.debug)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 545, in dispatch
return method(*args, **kwargs)
File "PATH_TO_PROJECT_FOLDER\main.py", line 125, in post
configure_remote_api_dev_safe ('{}.appspot.com'.format(app))
File "PATH_TO_PROJECT_FOLDER\main.py", line 38, in configure_remote_api_dev_safe'/_ah/remote_api')
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\google\appengine\ext\remote_api\remote_api_stub.py", line 1003, in ConfigureRemoteApiForOAuth 'oauth2client module: %s' % e)
ImportError: Use of OAuth credentials requires the oauth2client module: No module named oauth2client
ERROR 2018-07-20 08:46:57,765 wsgi.py:279]
Traceback (most recent call last):
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\google\appengine\runtime\wsgi.py", line 267, in Handle
result = handler(dict(self._environ), self._StartResponse)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\google\appengine\ext\ndb\tasklets.py", line 1108, in add_context_wrapper
return synctaskletfunc(*args, **kwds)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\google\appengine\ext\ndb\tasklets.py", line 1087, in synctasklet_wrapper
return taskletfunc(*args, **kwds).get_result()
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\google\appengine\ext\ndb\tasklets.py", line 1057, in tasklet_wrapper
result = func(*args, **kwds)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1519, in __call__
response = self._internal_error(e)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1511, in __call__
rv = self.handle_exception(request, response, e)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1505, in __call__
rv = self.router.dispatch(request, response)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1253, in default_dispatcher
return route.handler_adapter(request, response)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1077, in __call__
return handler.dispatch()
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 547, in dispatch
return self.handle_exception(e, self.app.debug)
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 545, in dispatch
return method(*args, **kwargs)
File "PATH_TO_PROJECT_FOLDER\main.py", line 125, in post
configure_remote_api_dev_safe ('{}.appspot.com'.format(app))
File "PATH_TO_PROJECT_FOLDER\main.py", line 38, in configure_remote_api_dev_safe '/_ah/remote_api')
File "SDK_PATH\Google\Cloud SDK\google-cloud-sdk\platform\google_appengine\google\appengine\ext\remote_api\remote_api_stub.py", line 1003, in ConfigureRemoteApiForOAuth 'oauth2client module: %s' % e)
ImportError: Use of OAuth credentials requires the oauth2client module: No module named oauth2client
INFO 2018-07-20 10:46:57,782 module.py:880] default: "POST / HTTP/1.1" 500 -
I hope that this is more explanatory. Thank you again in advance for your help!
Solution : (Thanks to #Dan Cornilescu)
=> Simply never forget the "import dev_appserver" and the call to "dev_appserver.fix_sys_path()"
I had them lost at the first place because of code versioning (a bad cherry pick) while I thought I had everything right.
Yet I'm not done and I'm facing a new issue that I m going to type down in a new question because its unrelated to the cause of this one(I hope nothing else got lost at some point). [ if you are curious about the the new issue its right here]

Answer 1

Converting the relevant comment to an answer.
The code snippet you shown seems to be missing this apparently needed setup section from the Using the Remote API in a local client example:
try:
import dev_appserver
dev_appserver.fix_sys_path()
except ImportError:
print('Please make sure the App Engine SDK is in your PYTHONPATH.')
raise