soon/datastore-emulator repository overview

⁠Google Cloud Datastore Emulator

A Google Cloud Datastore Emulator⁠ container image. The image is meant to be used for creating an standalone emulator for testing.

⁠Environment

The following environment variables must be set:

• DATASTORE_LISTEN_ADDRESS: The address should refer to a listen address, meaning that 0.0.0.0 can be used. The address must use the syntax HOST:PORT, for example 0.0.0.0:8081. The container must expose the port used by the Datastore emulator.
• DATASTORE_PROJECT_ID: The ID of the Google Cloud project for the emulator.

⁠Connect application with the emulator

The following environment variables need to be set so your application connects to the emulator instead of the production Cloud Datastore environment:

• DATASTORE_EMULATOR_HOST: The listen address used by the emulator.
• DATASTORE_PROJECT_ID: The ID of the Google Cloud project used by the emulator.

⁠Custom commands

This image contains a script named start-datastore (included in the PATH). This script is used to initialize the Datastore emulator.

⁠Starting an emulator

By default, the following command is called:

start-datastore

⁠Starting an emulator with options

This image comes with the following options: --no-store-on-disk and --consistency. Check Datastore Emulator Start⁠. --legacy, --data-dir and --host-port are not supported by this image.

start-datastore --no-store-on-disk --consistency=1.0

⁠Creating a Datastore emulator with Docker Compose

The easiest way to create an emulator with this image is by using Docker Compose⁠. The following snippet can be used as a docker-compose.yml for a datastore emulator:

version: "2"

services:
  datastore:
    image: singularities/datastore-emulator
    environment:
      - DATASTORE_PROJECT_ID=project-test
      - DATASTORE_LISTEN_ADDRESS=0.0.0.0:8081
    ports:
      - "8081:8081"

⁠Persistence

The image has a volume mounted at /opt/data. To maintain states between restarts, mount a volume at this location.