What are the differences between these GAE libraries?

Question

Throughout the Google App Engine documentation for Go, they use libraries interchangeably. Here's an example:

import "cloud.google.com/go/datastore"
import "google.golang.org/appengine/datastore"

Which of these libraries should I use and what are the key differences?

Answer 1

cloud.google.com/go/datastore is a client library for the Cloud Datastore rest API (available from anywhere).

google.golang.org/appengine/datastore is part from App Engine API (available only from App Engine).