Python: Save data in google cloud datastore emulator

Question

I am trying to test google's cloud datastore locally. My test steps are:

1. Crawl data using Scrapy
2. Save data to the cloud datastore using local emulator

I followed all the steps in order to use the local emulator

1. start local emulator: gcloud beta emulators datastore start
2. set local environment variables: gcloud beta emulators datastore env-init

However, in python, when use the following command to access cloud datastore, it always save the data directly to google cloud instead of saving them to the local emulators

#Imports the Google Cloud client library
from google.cloud import datastore

# Instantiates a client
datastore_client = datastore.Client()

sample_entry = some_data

# Saves the entity
datastore_client.put(sample_entry)

It seems like you cannot specify the library to use the local datastore emulator, just like what they offer in their Node.js client

var datastore = gcloud.datastore({
        apiEndpoint: "http://localhost:8380"
});

My question is, How can I ask the google cloud datastore python library to use local emulator instead of using the cloud directly

Answer 1

You need to eval $(gcloud beta emulators datastore env-init) .

gcloud beta emulators datastore env-init only prints the commands that set the necessary environment variables.

Answer 2

You can try something like

if os.getenv('SERVER_SOFTWARE', '').startswith('Google App Engine/'):
  # Production
else:
  # Local development server

You can follow more here, https://cloud.google.com/appengine/docs/standard/python/tools/using-local-server