Can Google Cloud functions share a datastore with Appengine?

Question

I have an old AppEngine Java application using the AppEngine datastore. Is this what the marketing renamers at Google now (2019) call "Cloud Datastore"?

Can I create Google Cloud Functions that interact with the same datastore, and what are the steps needed to do so?

Answer 1

Yes, it's the same datastore. Also called/soon-to-be Cloud Firestore in Datastore mode (which all older apps will be converted to at some point).

Yes, you can access it from anywhere, even from outside Google Cloud. From Cloud Datastore (emphasis mine):

You can access Cloud Datastore from anywhere using the Cloud Datastore API. Use the Google Cloud client libraries to store and retrieve data from Cloud Datastore.

The same Cloud Datastore data is available regardless of if you use the App Engine libraries, the Google Cloud client libraries, or call the API directly.

The major steps to access the datastore from a Cloud Function:

• you can't use the GAE-specific client libraries like the one you likely used in your old app, you'll have to use one of the generic client libraries (or the REST or RPC APIs)
• you'll have to give your CF's Identity/service account the proper access permissions, see Setting up authentication and Accessing your database from another platform.