pull a docker image from a mirror source

docker-pull.sh

#!/bin/bash
repo=azk8s.cn

function rip() {
  echo $1 | awk -F '/' '{
    { 
      if (NF == 1)
        print "dockerhub." repo "/library/" $0
      else if ($1 == "docker.io")
        print "dockerhub." repo "/" substr($0, length($1)+2, length($0)-length($1))
      else if ($1 == "k8s.gcr.io")
        print "gcr." repo "/google_containers/" substr($0, length($1)+2, length($0)-length($1))
      else if ($1 == "gcr.io")
        print "gcr." repo "/" substr($0, length($1)+2, length($0)-length($1))
      else if ($1 == "quay.io")
        print "quay." repo "/" substr($0, length($1)+2, length($0)-length($1))
      else
        print "dockerhub." repo "/" $0
    }
  }' repo=$repo
}

function pull() {
  url=`rip $1`
  docker pull $url
  docker tag $url $1
  docker rmi $url
}

function file() {
  while IFS= read -r line; do
    echo "docker pull: $line"
    pull $line
  done < $1
}

if [ $1 == "-f" ]; then
  file $2
else
  pull $1
fi