ImportError: cannot import name cygrpc - python-2.7

Question

I am trying to use Firebase Native mode on Google App Engine - Standard. My python language is Python 2.7. When I try to from google.cloud import firestore, I get an error ImportError: cannot import name cygrpc
I have deployed virtualenv described in the documentation here.
pip install virtualenv
virtualenv env
source env/bin/activate
My appengine_config.py is
from google.appengine.ext import vendor
import os.path
# Add any libraries installed in the "lib" folder.
vendor.add('lib')
vendor.add(os.path.join(os.path.dirname(os.path.realpath(__file__)), 'lib'))
my_app.py includes
from google.appengine.ext.webapp import template
from google.appengine.ext import ndb
from google.appengine.api import mail
import os
from google.cloud import firestore
(/base/alloc/tmpfs/dynamic_runtimes/python27g/43d5822312de17fd/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py:269)
Traceback (most recent call last):
File "/base/alloc/tmpfs/dynamic_runtimes/python27g/43d5822312de17fd/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 240, in Handle
handler = _config_handle.add_wsgi_middleware(self._LoadHandler())
File "/base/alloc/tmpfs/dynamic_runtimes/python27g/43d5822312de17fd/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 311, in _LoadHandler
handler, path, err = LoadObject(self._handler)
File "/base/alloc/tmpfs/dynamic_runtimes/python27g/43d5822312de17fd/python27/python27_lib/versions/1/google/appengine/runtime/wsgi.py", line 85, in LoadObject
obj = __import__(path[0])
File "/base/data/home/apps/s~openbarn-prod/20190602t102855.418624175446659791/main.py", line 4, in <module>
from controllers import server, common, header
File "/base/data/home/apps/s~openbarn-prod/20190602t102855.418624175446659791/controllers/server.py", line 10, in <module>
from google.cloud import firestore
File "/base/data/home/apps/s~openbarn-prod/20190602t102855.418624175446659791/lib/google/cloud/firestore.py", line 18, in <module>
from google.cloud.firestore_v1 import __version__
File "/base/data/home/apps/s~openbarn-prod/20190602t102855.418624175446659791/lib/google/cloud/firestore_v1/__init__.py", line 22, in <module>
from google.cloud.firestore_v1._helpers import GeoPoint
File "/base/data/home/apps/s~openbarn-prod/20190602t102855.418624175446659791/lib/google/cloud/firestore_v1/_helpers.py", line 21, in <module>
import grpc
File "/base/data/home/apps/s~openbarn-prod/20190602t102855.418624175446659791/lib/grpc/__init__.py", line 23, in <module>
from grpc._cython import cygrpc as _cygrpc
ImportError: cannot import name cygrpc
The question I have - can you use Firestore Native mode on Google App Engine Standard using Python 2.7? I need GAE- Standard because we are using Google Endpoint that is not support on GAE-Flex.
The doc here says App Engine Client library integration is not supported on Python2.7 GAE Standard environment. But I am not trying App Engine Client library, I am trying App Engine Server library in GAE Standard Environment.
How do I solve for import error for cygrpc? The solution here, says -
python -m pip install grpcio --ignore-installed
Is this recommended?

Answer 1

It's 2020, and you can now use grpcio (without explicitly adding it yourself as it's a built-in library) w/Cloud Firestore natively on App Engine with Python 2.7. Three things to make this work:
Add google-cloud-firestore to your requirements.txt file and install with pip install -U -t lib -r requirements.txt.
Add these lines to the libraries section of your app.yaml file:
libraries:
- name: grpcio
version: 1.0.0
- name: setuptools
version: 36.6.0
Ensure these lines are in your appengine_config.py file:
import pkg_resources
from google.appengine.ext import vendor
# Set path to your libraries folder.
path = 'lib'
# Add libraries installed in the path folder.
vendor.add(path)
# Add libraries to pkg_resources working set to find the distribution.
pkg_resources.working_set.add_entry(path)
Of course, we do recommend you eventually migrate to Python 3 to take advantage of the greater flexibility the next generations (of Python and App Engine) provide, esp. the ability to tap into other GCP services. However, caveat such a port isn't without effort if your app is complex & deeply-dependent on App Engine's 1st gen built-in services. Most of the suggestions above are derived from this section of the migration docs.
Once you're on Python 3, everything related to 3P libraries on App Engine becomes much easier, as I demonstrate in this other SO answer.

Answer 2

A while ago GRPC wasn't supported on GAE standard, see GRPC and types import error in App Engine Datastore. I didn't try since, but I don't see newer activity on issue 149.
Also the cython reference in the traceback suggests that it may include compiled code, which would violate the pure python standard environment sandbox restrictions that applies to the code you deploy.

Answer 3

Make sure that your installed python version bit(32/64) and your system bit(32/64) are matched.
If they are not matched please follow the solution mentioned at https://azurelessons.com/cannot-import-name-cygrpc/