docker registry donload alpine layer blob

download-alpine-tar.sh

token() { 
  scope=${1:?scope required}
  export T=$(curl -s 'https://auth.docker.io/token?service=registry.docker.io&scope=repository:'$scope | jq .token -r; )
}

blobUrl() {
  repo=${1:?required repo (library/alpine)}
  token ${repo}:pull
  export BLOBURL=$(curl -Lsi -H "Authorization: Bearer $T"  https://registry-1.docker.io/v2/library/alpine/blobs/${BLOB}| sed -n '/^Location:/ {s/.$//;s/Location: //p;}')
  echo BLOBURL=$BLOBURL
}

pullImage() {
  image=${1:? required  image (library/alpine)}
  set -x
  token ${image}:pull
  BLOB=$(curl -s -H "Authorization: Bearer $T"  https://registry-1.docker.io/v2/${image}/manifests/latest| jq '.fsLayers[-1].blobSum' -r)
  mkdir -p ${image#*/}
  curl -Ls -H "Authorization: Bearer $T"  https://registry-1.docker.io/v2/${image}/blobs/${BLOB} | tar -xzv -C ${image#*/}
  set +x
}

pullImage library/alpine
pullImage library/busybox

golang-alpine-install.sh

# download 1 single docker image layer (https://github.com/docker-library/golang/blob/9bf6daddb324a4d8e82b0613cf348a6eff363f95/1.10/alpine3.7/Dockerfile#L10)
# and untar the relevant dir (usr/local/go) into '/'
# first you have to ask for a fresh Bearer token with scope=repository:library/img:tag

# apk add --no-cache curl jq bash && bash

curl -Ls \
  -H "Authorization: Bearer $(curl -s 'https://auth.docker.io/token?service=registry.docker.io&scope=repository:library/golang:pull' | jq .token -r)" \
  https://registry-1.docker.io/v2/library/golang/blobs/sha256:6487ee6212c57a47feb500f1421c38a83cd1ab7def383ffc49804d9d56970cbb \
    | tar -xzv -T <(echo usr/local/go) -C /
    
export PATH=/usr/local/go/bin/:$PATH
go version