Support gcloud local GCP Application Default Credentials in dmake shell/test #536
Description
Context
To authenticate to GCP, at run-time (deployed, in kubernetes) we can use Workload Identity (https://cloud.google.com/kubernetes-engine/docs/concepts/workload-identity or even https://cloud.google.com/iam/docs/workload-identity-federation).
But at dev-time (dmake shell, dmake test) we don't have a proper solution to authenticate the developer.
GCP recommends using "Application Default Credentials" (cf https://cloud.google.com/docs/authentication/best-practices-applications):
- one-time setup https://cloud.google.com/sdk/gcloud/reference/auth/application-default/login
- GCP libraries transparently use that to authenticate the developer as themselves
Feature request
DMake could support ~transparent mounting whatever is needed for GCP Application Default Credentials so that developers running dmake shell / dmake test are authenticated as themselves to GCP as if they developed locally on their host