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Bash script to allow you to use `FROM image` in Dockerfiles even when using a private registry
#!/usr/bin/env bash
readonly _skip_examples="local-image-skip-examples"
usage() {
local scriptname
scriptname="$(basename "$0")"
cat <<-EOF
Usage: ${scriptname} command
Commands:
fetch IMAGE REGISTRY Fetch a local-tagged copy of IMAGE from REGISTRY
push IMAGE REGISTRY Push IMAGE to REGISTRY
clean local IMAGE Remove a local-tagged copy of IMAGE
clean remote IMAGE REGISTRY Remove a REGISTRY-tagged copy of IMAGE
clean both IMAGE REGISTRY Remove both local- and REGISTRY-tagged IMAGE
EOF
[[ "$1" == "$_skip_examples" ]] && return
cat <<-EOF
Examples:
${scriptname} fetch company/service:2.5 docker.example.com
Pull docker.example.com/company/service:2.5 and tag it locally as
company/service:2.5.
${scriptname} push company/service:2.5 docker.example.com
Tag company/service:2.5 as docker.example.com/company/service:2.5
and push it to the registry.
${scriptname} clean local company/service:2.5
Remove company/service:2.5 from the local system.
${scriptname} clean remote company/service:2.5 docker.example.com
Remove docker.example.com/company/service:2.5 from the local system.
${scriptname} clean both company/service:2.5 docker.example.com
Remove docker.example.com/company/service:2.5 and company/service:2.5
from the local system.
EOF
}
_retag() {
if [[ "$#" -ne 2 ]]; then
echo "${FUNCNAME[0]}: Expected 2 arguments, got ${#}." >&2
return 1
fi
declare source="$1" dest="$2"
echo "Tagging ${source} as ${dest}..."
docker tag "$source" "$dest"
}
fetch() {
if [[ "$#" -ne 2 ]]; then
echo "${FUNCNAME[0]}: Expected 2 arguments, got ${#}." >&2
usage "$_skip_examples"
return 1
fi
declare image="$1" registry="$2"
local remoteimage="${registry}/${image}"
echo "Pulling ${remoteimage}..."
docker pull "$remoteimage"
echo
_retag "$remoteimage" "$image"
}
push() {
if [[ "$#" -ne 2 ]]; then
echo "${FUNCNAME[0]}: Expected 2 arguments, got ${#}." >&2
usage "$_skip_examples"
return 1
fi
declare image="$1" registry="$2"
local remoteimage="${registry}/${image}"
_retag "$image" "$remoteimage"
echo
echo "Pushing ${remoteimage}..."
docker push "$remoteimage"
}
clean() {
case "$1" in
local) shift; _clean_local "$@";;
remote) shift; _clean_remote "$@";;
both)
shift
_clean_local "$@"
_clean_remote "$@"
;;
*) usage;;
esac
}
_clean_local() {
if [[ "$#" -lt 1 ]] || [[ "$#" -gt 2 ]]; then
echo "${FUNCNAME[0]}: Expected 1 argument, got ${#}." >&2
usage
return 1
fi
declare image="$1"
docker rmi "$image" || true
}
_clean_remote() {
if [[ "$#" -ne 2 ]]; then
echo "${FUNCNAME[0]}: Expected 2 arguments, got ${#}." >&2
usage
return 1
fi
declare image="$1" registry="$2"
local remoteimage="${registry}/${image}"
docker rmi "$remoteimage" || true
}
main() {
set -eo pipefail; [[ -n "$TRACE" ]] && set -x
case "$1" in
fetch) shift; fetch "$@";;
push) shift; push "$@";;
clean) shift; clean "$@";;
*) usage;;
esac
}
[[ "$0" == "${BASH_SOURCE[0]}" ]] && main "$@"
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