How to know if docker is already logged in to a docker registry server

Question

I\'m not sure if I have already logged in to a docker registry in cmd line by using cmd: docker login. How can you test or see whether you are logged in or not, without tryi

Answer 1

My AWS ECR build-script has:

ECR_HOSTNAME="${ACCOUNT_ID}.dkr.ecr.${REGION}.amazonaws.com"
TOKEN=$(jq -r '.auths["'$ECR_HOSTNAME'"]["auth"]' ~/.docker/config.json)
curl --fail --header "Authorization: Basic $TOKEN" https://$ECR_HOSTNAME/v2/

If accessing ECR fails, a login is done:

aws ecr get-login-password --region ${REGION} | docker login --username AWS --password-stdin https://$ECR_HOSTNAME

For this to work, a proper Docker credential store cannot be used. Default credentials store of ~/.docker/config.json is assumed.