Sidecar containers are often required for testing, such as having a Postgres database available while running integration tests. These containers should be configurable in a Kraken build script, and it should be possible to start these containers directly and also have them start for tests.

In the build script, an example container definition may be:

from kraken.std.devenv import sidecar_container

sidecar_container(
  name="postgres",
  image="postgres:latest",
  ports=["5432:5432"],
  env={"POSTGRES_PASSWORD": "alpine"},
)

This should produce two targets, :postgres.start and :postgres.run. The :postgres.start task starts up the container in the background. The :postgres.run command is intended to be used on the CLI to wait for the container to complete or to cancel it when the task is interrupted.

For tests, the :postgres.start command would simply need to be a dependency on the task that runs the tests. It being a background task, the Postgers container will stay alive until the tests have completed.