Dockerhub decrements your limit even if it doesn't pull layers

rate-limit-decrementing.sh

# show that dockerhub is decrementing your allowed pulls when you re-request a "latest" image
sudo yum install jq
export TOKEN=$(curl "https://auth.docker.io/token?service=registry.docker.io&scope=repository:ratelimitpreview/test:pull" | jq -j '.token'); echo $TOKEN
while true; do
  echo $(curl --head -H "Authorization: Bearer $TOKEN" https://registry-1.docker.io/v2/ratelimitpreview/test/manifests/latest 2>&1 | grep RateLimit-Remaining)
  docker pull alpine:latest
  sleep 3
done