Google Datastore and NDB Emulator with Python3 and Flask

For the example code go to https://github.com/ReddingSoftware/Google_NDB_Emulator

# Google_NDB_Emulator
This allows you to test your Google NDB code locally in a development environment with Python3 and Flask rather than working with your actual database.
It lets you work with the Google Cloud Datastore emulator to test your Google NDB code.

Adding the necessary code to your existing Flask Google NDB project:

note: when referring to the terminal it should be your command line terminal. Don’t use PowerShell.

Step 1: To your existing code add:
import mock
from flask import Flask
from google.cloud import ndb
import google.auth.credentials
import os

os.environ["DATASTORE_DATASET"] = "test"
os.environ["DATASTORE_EMULATOR_HOST"] = "127.0.0.1:8001"
os.environ["DATASTORE_EMULATOR_HOST_PATH"] = "127.0.0.1:8001/datastore"
os.environ["DATASTORE_HOST"] = "http://127.0.0.1:8001"
os.environ["DATASTORE_PROJECT_ID"] = "test"

credentials = mock.Mock(spec=google.auth.credentials.Credentials)

step 1.5 Anywhere you want to test the database add:
client = ndb.Client(project="test", credentials=credentials)
with client.context():

Step 2: Install google cloud SDK if you haven't already done so https://cloud.google.com/sdk/docs/install

Step3: After navigating to your project folder in your terminal run: gcloud components install cloud-datastore-emulator
(if you want more on datastore-emulator go to https://cloud.google.com/datastore/docs/tools/datastore-emulator)

Step 4: in your terminal run:
pip install datastore-viewer

Step 5: add the requirements.txt info to your current requirements.txt and in your terminal run:
pip install -r requirements.txt

Step 6: in your terminal run:
gcloud beta emulators datastore start --data-dir=. --project test --host-port "127.0.0.1:8001"

Step 7: Open a new terminal but leave the emulator terminal running. This can be done in visual studio code by clicking the plus sign on choosing Terminal and New Terminal.

Step8: Make sure you are still navigated to the NDBEmulator folder in your terminal.

Step 9: in your new terminal run:
For mac:
export FLASK_APP=main
(press return)
export FLASK_ENV=development
(press return)
flask run
For PC:
set FLASK_APP=main
(press return)
set FLASK_ENV=development
(press return)
flask run

Alternatively, you can run:
python3 main.py

or just

python main.py

For info on how to run Flask from the command line on Visual Studio Code go here https://docs.google.com/document/d/1bbWogGdQ48rMJFB9Wxvtt7XWw5SUfP07BVl6cHk69hk/edit?usp=sharing


Step 10: in your browser go to http://127.0.0.1:5000
(you'll see the main page)

Step 11: go to http://127.0.0.1:5000/test
(you'll see what has been added to the local database)

step12: Open a 3rd terminal. Make sure you are still navigated to the NDBEmulator folder in your new terminal.

step 13: in your new terminal run:
For Mac:
export DATASTORE_EMULATOR_HOST=localhost:8001 && datastore-viewer
For PC:
set DATASTORE_EMULATOR_HOST=localhost:8001 && datastore-viewer

Step 14: in your browser go to http://127.0.0.1:8082/

Step 15: in the search box in the upper left-hand corner type:
test

Step16:
hit refresh and it should show you the data saved in your local development database