dockerTools: add nix-prefetch-docker script

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Jaka Hudoklin 2019-03-26 12:33:43 +01:00 committed by Jaka Hudoklin
parent 373488e6f4
commit c1f0d19785
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GPG key ID: 916062A1C4748647
4 changed files with 230 additions and 12 deletions

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@ -436,18 +436,7 @@ pullImage {
<callout arearefs='ex-dockerTools-pullImage-2'>
<para>
<varname>imageDigest</varname> specifies the digest of the image to be
downloaded. Skopeo can be used to get the digest of an image, with its
<varname>inspect</varname> subcommand. Since a given
<varname>imageName</varname> may transparently refer to a manifest list of
images which support multiple architectures and/or operating systems,
supply the `--override-os` and `--override-arch` arguments to specify
exactly which image you want. By default it will match the OS and
architecture of the host the command is run on.
<programlisting>
$ nix-shell --packages skopeo jq --command "skopeo --override-os linux --override-arch x86_64 inspect docker://docker.io/nixos/nix:1.11 | jq -r '.Digest'"
sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b
</programlisting>
This argument is required.
downloaded. This argument is required.
</para>
</callout>
<callout arearefs='ex-dockerTools-pullImage-3'>
@ -477,6 +466,34 @@ sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b
</para>
</callout>
</calloutlist>
<para>
<literal>nix-prefetch-docker</literal> command can be used to get required
image parameters:
<programlisting>
$ nix run nixpkgs.nix-prefetch-docker -c nix-prefetch-docker --image-name mysql --image-tag 5
</programlisting>
Since a given <varname>imageName</varname> may transparently refer to a
manifest list of images which support multiple architectures and/or
operating systems, you can supply the <option>--os</option> and
<option>--arch</option> arguments to specify exactly which image you want.
By default it will match the OS and architecture of the host the command is
run on.
<programlisting>
$ nix-prefetch-docker --image-name mysql --image-tag 5 --arch x86_64 --os linux
</programlisting>
Desired image name and tag can be set using
<option>--final-image-name</option> and <option>--final-image-tag</option>
arguments:
<programlisting>
$ nix-prefetch-docker --image-name mysql --image-tag 5 --final-image-name eu.gcr.io/my-project/mysql --final-image-tag prod
</programlisting>
</para>
</section>
<section xml:id="ssec-pkgs-dockerTools-exportImage">

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@ -0,0 +1,173 @@
#! /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 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 --override-os ${os} --override-arch ${arch} copy "$sourceUrl" "docker-archive://$tmpFile:$finalImageName:$finalImageTag"
else
skopeo --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"
echo "-> ImageDigest: $imageDigest"
echo "-> FinalImageName: $finalImageName"
echo "-> FinalImageTag: $finalImageTag"
echo "-> ImagePath: $finalPath"
echo "-> ImageHash: $imageHash"
fi
if [ "$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

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@ -0,0 +1,26 @@
{ stdenv, makeWrapper, nix, skopeo }:
with stdenv.lib;
stdenv.mkDerivation {
name = "nix-prefetch-docker";
nativeBuildInputs = [ makeWrapper ];
unpackPhase = ":";
installPhase = ''
install -vD ${./nix-prefetch-docker} $out/bin/$name;
wrapProgram $out/bin/$name \
--prefix PATH : ${makeBinPath [ nix skopeo ]} \
--set HOME /homeless-shelter
'';
preferLocalBuild = true;
meta = {
description = "Script used to obtain source hashes for dockerTools.pullImage";
maintainers = with maintainers; [ offline ];
platforms = platforms.unix;
};
}

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@ -170,6 +170,8 @@ in
dockerTools = callPackage ../build-support/docker { };
nix-prefetch-docker = callPackage ../build-support/docker/nix-prefetch-docker.nix { };
docker-compose = python3Packages.callPackage ../applications/virtualization/docker-compose {};
docker-ls = callPackage ../tools/misc/docker-ls { };