Activate a service account for gcloud. The volumes from this container can be used in subsequent cloud-builders to use this activated account. Usage:

0. Define an environment variable GCLOUD_SERVICE_KEY that holds the service account key; this should be base64 encoded, and it should be SECRET!

1. Create a volume to be shared between gcloud-derived containers:

• docker volume create activated_service-account

2. Run the gcloud-config container to activate a Google Cloud service account

• docker run -it --rm --mount source=activated_service-account,target=/root/.config/gcloud -e GCLOUD_SERVICE_KEY=${GCLOUD_SERVICE_KEY} unspecifiedllc/gcloud-config:latest

3. In subsequent containers that should operate as the activated service account, mount the volume same volume

• docker run -it --rm --mount source=activated_service-account,target=/root/.config/gcloud gcr.io/cloud-builders/gcloud auth list