Removes the Docker images and also able to add some exclusions for image deletion

docker_image-remover.sh

#!/bin/bash

#================================================
# Removes the Docker images based on conditions
#================================================

# Variable Declaration
declare -A image_exclusion=( ["node"]="8-alpine" ["jenkins"]="latest" )

# Checks whether image has been excluded or not
imageExclusionChecker() {
  if [[ ! ( ! -z ${image_exclusion[$1]} && ${image_exclusion[$1]} == $2 ) ]]
  then
    return 1
  else
    return 0
  fi
}

# Removes the Docker image
removeImages() {
  local iteration=0
  while read name tag imageid rest
  do
    # Skips the first iteration, since it contains only headers
    if [ $iteration == 0 ]
    then
      iteration=` expr $iteration + 1 `
      continue
    fi
    # Checks whether the image has been excluded from deletion
    imageExclusionChecker $name $tag
    if [ $? == 1 ]
    then
      docker rmi -f $imageid
    else
      continue
    fi
  done << EOF
$(docker images -a)
EOF

}

# Main flow of execution
main() {
  # Removes the Docker iamges
  removeImages
}

# Starts the Execution
main

exit 0