Google Cloud Datastore Emulator

To develop and test your application locally, you can use the Google Cloud Datastore Emulator, which provides local emulation of the production Google Cloud Datastore environment. You can start the Google Cloud Datastore emulator using the gcloud command-line tool.

When you run the Cloud Datastore emulator you will see a message similar to the following printed:

If you are using a library that supports the DATASTORE_EMULATOR_HOST
environment variable, run:

  export DATASTORE_EMULATOR_HOST=localhost:8978

Now you can connect to the emulator using the DATASTORE_EMULATOR_HOST environment variable:

require "google/cloud/datastore"

# Make Datastore use the emulator
ENV["DATASTORE_EMULATOR_HOST"] = "localhost:8978"

datastore = Google::Cloud::Datastore.new project: "emulator-project-id"

task = datastore.entity "Task", "emulatorTask" do |t|
  t["type"] = "Testing"
  t["done"] = false
  t["priority"] = 5
  t["description"] = "Use Datastore Emulator"
end

datastore.save task

Or by providing the emulator_host argument:

require "google/cloud/datastore"

datastore = Google::Cloud::Datastore.new emulator_host: "localhost:8978"

task = datastore.entity "Task", "emulatorTask" do |t|
  t["type"] = "Testing"
  t["done"] = false
  t["priority"] = 5
  t["description"] = "Use Datastore Emulator"
end

datastore.save task