I was able to export entities into a storage bucket without much difficulty with this command:
gcloud datastore export --kinds=\"KIND1,KIND2\" --namespaces=\
The Datastore Emulator now supports import and export:
Import:
curl -X POST localhost:8081/v1/projects/[PROJECT_ID]:import \
-H 'Content-Type: application/json' \
-d '{"input_url":"[ENTITY_EXPORT_FILES]"}'
Export:
curl -X POST localhost:8081/v1/projects/[PROJECT_ID]:export \
-H 'Content-Type: application/json' \
-d '{"output_url_prefix":"EXPORT_DIRECTORY"}'
https://cloud.google.com/datastore/docs/tools/emulator-export-import