nixpkgs/pkgs/build-support/docker/nix-prefetch-docker
edef de88771a7d nix-prefetch-docker: output informational messages to stderr
Informational messages belong on stderr, not on stdout and intermixed
with structured output for programmatic use.

Change-Id: I34d094d04460494e9ec8953db7490f4e2292d959
2020-12-01 16:58:29 +00:00

174 lines
4.1 KiB
Bash
Executable File

#! /usr/bin/env bash
set -e -o pipefail
os=
arch=
imageName=
imageTag=
imageDigest=
finalImageName=
finalImageTag=
hashType=$NIX_HASH_ALGO
hashFormat=$hashFormat
format=nix
usage(){
echo >&2 "syntax: nix-prefetch-docker [options] [IMAGE_NAME [IMAGE_TAG|IMAGE_DIGEST]]
Options:
--os os OS to fetch image for
--arch linux Arch to fetch image for
--image-name name Name of the image to fetch
--image-tag tag Image tag
--image-digest digest Image digest
--final-image-name name Desired name of the image
--final-image-tag tag Desired image tag
--json Output result in json format instead of nix
--quiet Only print the final result
"
exit 1
}
get_image_digest(){
local imageName=$1
local imageTag=$2
if test -z "$imageTag"; then
imageTag="latest"
fi
skopeo --insecure-policy --tmpdir=$TMPDIR inspect "docker://$imageName:$imageTag" | jq '.Digest' -r
}
get_name() {
local imageName=$1
local imageTag=$2
echo "docker-image-$(echo "$imageName:$imageTag" | tr '/:' '-').tar"
}
argi=0
argfun=""
for arg; do
if test -z "$argfun"; then
case $arg in
--os) argfun=set_os;;
--arch) argfun=set_arch;;
--image-name) argfun=set_imageName;;
--image-tag) argfun=set_imageTag;;
--image-digest) argfun=set_imageDigest;;
--final-image-name) argfun=set_finalImageName;;
--final-image-tag) argfun=set_finalImageTag;;
--quiet) QUIET=true;;
--json) format=json;;
--help) usage; exit;;
*)
: $((++argi))
case $argi in
1) imageName=$arg;;
2) [[ $arg == *"sha256"* ]] && imageDigest=$arg || imageTag=$arg;;
*) exit 1;;
esac
;;
esac
else
case $argfun in
set_*)
var=${argfun#set_}
eval $var=$arg
;;
esac
argfun=""
fi
done
if test -z "$imageName"; then
usage
fi
if test -z "$os"; then
os=linux
fi
if test -z "$arch"; then
arch=amd64
fi
if test -z "$hashType"; then
hashType=sha256
fi
if test -z "$hashFormat"; then
hashFormat=base32
fi
if test -z "$finalImageName"; then
finalImageName="$imageName"
fi
if test -z "$finalImageTag"; then
if test -z "$imageTag"; then
finalImageTag="latest"
else
finalImageTag="$imageTag"
fi
fi
if test -z "$imageDigest"; then
imageDigest=$(get_image_digest $imageName $imageTag)
fi
sourceUrl="docker://$imageName@$imageDigest"
tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/skopeo-copy-tmp-XXXXXXXX")"
trap "rm -rf \"$tmpPath\"" EXIT
tmpFile="$tmpPath/$(get_name $finalImageName $finalImageTag)"
if test -z "$QUIET"; then
skopeo --insecure-policy --tmpdir=$TMPDIR --override-os ${os} --override-arch ${arch} copy "$sourceUrl" "docker-archive://$tmpFile:$finalImageName:$finalImageTag" >&2
else
skopeo --insecure-policy --tmpdir=$TMPDIR --override-os ${os} --override-arch ${arch} copy "$sourceUrl" "docker-archive://$tmpFile:$finalImageName:$finalImageTag" > /dev/null
fi
# Compute the hash.
imageHash=$(nix-hash --flat --type $hashType --base32 "$tmpFile")
# Add the downloaded file to Nix store.
finalPath=$(nix-store --add-fixed "$hashType" "$tmpFile")
if test -z "$QUIET"; then
echo "-> ImageName: $imageName" >&2
echo "-> ImageDigest: $imageDigest" >&2
echo "-> FinalImageName: $finalImageName" >&2
echo "-> FinalImageTag: $finalImageTag" >&2
echo "-> ImagePath: $finalPath" >&2
echo "-> ImageHash: $imageHash" >&2
fi
if [ "$format" == "nix" ]; then
cat <<EOF
{
imageName = "$imageName";
imageDigest = "$imageDigest";
sha256 = "$imageHash";
finalImageName = "$finalImageName";
finalImageTag = "$finalImageTag";
}
EOF
else
cat <<EOF
{
"imageName": "$imageName",
"imageDigest": "$imageDigest",
"sha256": "$imageHash",
"finalImageName": "$finalImageName",
"finalImageTag": "$finalImageTag"
}
EOF
fi