a31607f904
Warning about future breaking changes is wrong. - It suggests that the maintainers don't value backwards compatibility. They do. - It implies that other parts of Nixpkgs won't ever break. They will. - It implies that a well-defined "public" interface exists. It doesn't. - If the reasons above didn't apply, it should have been in the manual instead. Breaking changes will come, especially to the interface. That can be the only way we can make progress without breaking the image _contents_. I don't think dockerTools is any different from most of Nixpkgs in these regards.
870 lines
29 KiB
Nix
870 lines
29 KiB
Nix
{
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bashInteractive,
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buildPackages,
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cacert,
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callPackage,
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closureInfo,
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coreutils,
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docker,
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e2fsprogs,
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findutils,
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go,
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jq,
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jshon,
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lib,
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makeWrapper,
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moreutils,
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nix,
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pigz,
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rsync,
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runCommand,
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runtimeShell,
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shadow,
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skopeo,
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stdenv,
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storeDir ? builtins.storeDir,
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substituteAll,
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symlinkJoin,
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util-linux,
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vmTools,
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writeReferencesToFile,
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writeScript,
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writeText,
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writeTextDir,
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writePython3,
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system, # Note: This is the cross system we're compiling for
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}:
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let
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mkDbExtraCommand = contents: let
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contentsList = if builtins.isList contents then contents else [ contents ];
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in ''
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echo "Generating the nix database..."
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echo "Warning: only the database of the deepest Nix layer is loaded."
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echo " If you want to use nix commands in the container, it would"
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echo " be better to only have one layer that contains a nix store."
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export NIX_REMOTE=local?root=$PWD
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# A user is required by nix
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# https://github.com/NixOS/nix/blob/9348f9291e5d9e4ba3c4347ea1b235640f54fd79/src/libutil/util.cc#L478
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export USER=nobody
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${buildPackages.nix}/bin/nix-store --load-db < ${closureInfo {rootPaths = contentsList;}}/registration
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mkdir -p nix/var/nix/gcroots/docker/
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for i in ${lib.concatStringsSep " " contentsList}; do
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ln -s $i nix/var/nix/gcroots/docker/$(basename $i)
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done;
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'';
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# The OCI Image specification recommends that configurations use values listed
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# in the Go Language document for GOARCH.
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# Reference: https://github.com/opencontainers/image-spec/blob/master/config.md#properties
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# For the mapping from Nixpkgs system parameters to GOARCH, we can reuse the
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# mapping from the go package.
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defaultArch = go.GOARCH;
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in
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rec {
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examples = callPackage ./examples.nix {
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inherit buildImage buildLayeredImage fakeNss pullImage shadowSetup buildImageWithNixDb;
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};
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pullImage = let
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fixName = name: builtins.replaceStrings ["/" ":"] ["-" "-"] name;
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in
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{ imageName
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# To find the digest of an image, you can use skopeo:
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# see doc/functions.xml
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, imageDigest
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, sha256
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, os ? "linux"
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, arch ? defaultArch
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# This is used to set name to the pulled image
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, finalImageName ? imageName
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# This used to set a tag to the pulled image
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, finalImageTag ? "latest"
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, name ? fixName "docker-image-${finalImageName}-${finalImageTag}.tar"
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}:
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runCommand name {
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inherit imageDigest;
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imageName = finalImageName;
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imageTag = finalImageTag;
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impureEnvVars = stdenv.lib.fetchers.proxyImpureEnvVars;
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outputHashMode = "flat";
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outputHashAlgo = "sha256";
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outputHash = sha256;
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nativeBuildInputs = lib.singleton skopeo;
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SSL_CERT_FILE = "${cacert.out}/etc/ssl/certs/ca-bundle.crt";
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sourceURL = "docker://${imageName}@${imageDigest}";
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destNameTag = "${finalImageName}:${finalImageTag}";
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} ''
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skopeo --insecure-policy --tmpdir=$TMPDIR --override-os ${os} --override-arch ${arch} copy "$sourceURL" "docker-archive://$out:$destNameTag"
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'';
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# We need to sum layer.tar, not a directory, hence tarsum instead of nix-hash.
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# And we cannot untar it, because then we cannot preserve permissions ecc.
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tarsum = runCommand "tarsum" {
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nativeBuildInputs = [ go ];
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} ''
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mkdir tarsum
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cd tarsum
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cp ${./tarsum.go} tarsum.go
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export GOPATH=$(pwd)
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export GOCACHE="$TMPDIR/go-cache"
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mkdir -p src/github.com/docker/docker/pkg
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ln -sT ${docker.src}/components/engine/pkg/tarsum src/github.com/docker/docker/pkg/tarsum
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go build
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mkdir -p $out/bin
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cp tarsum $out/bin/
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'';
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# buildEnv creates symlinks to dirs, which is hard to edit inside the overlay VM
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mergeDrvs = {
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derivations,
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onlyDeps ? false
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}:
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runCommand "merge-drvs" {
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inherit derivations onlyDeps;
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} ''
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if [[ -n "$onlyDeps" ]]; then
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echo $derivations > $out
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exit 0
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fi
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mkdir $out
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for derivation in $derivations; do
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echo "Merging $derivation..."
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if [[ -d "$derivation" ]]; then
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# If it's a directory, copy all of its contents into $out.
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cp -drf --preserve=mode -f $derivation/* $out/
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else
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# Otherwise treat the derivation as a tarball and extract it
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# into $out.
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tar -C $out -xpf $drv || true
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fi
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done
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'';
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# Helper for setting up the base files for managing users and
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# groups, only if such files don't exist already. It is suitable for
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# being used in a runAsRoot script.
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shadowSetup = ''
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export PATH=${shadow}/bin:$PATH
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mkdir -p /etc/pam.d
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if [[ ! -f /etc/passwd ]]; then
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echo "root:x:0:0::/root:${runtimeShell}" > /etc/passwd
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echo "root:!x:::::::" > /etc/shadow
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fi
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if [[ ! -f /etc/group ]]; then
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echo "root:x:0:" > /etc/group
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echo "root:x::" > /etc/gshadow
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fi
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if [[ ! -f /etc/pam.d/other ]]; then
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cat > /etc/pam.d/other <<EOF
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account sufficient pam_unix.so
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auth sufficient pam_rootok.so
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password requisite pam_unix.so nullok sha512
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session required pam_unix.so
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EOF
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fi
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if [[ ! -f /etc/login.defs ]]; then
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touch /etc/login.defs
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fi
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'';
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# Run commands in a virtual machine.
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runWithOverlay = {
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name,
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fromImage ? null,
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fromImageName ? null,
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fromImageTag ? null,
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diskSize ? 1024,
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preMount ? "",
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postMount ? "",
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postUmount ? ""
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}:
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let
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result = vmTools.runInLinuxVM (
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runCommand name {
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preVM = vmTools.createEmptyImage {
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size = diskSize;
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fullName = "docker-run-disk";
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};
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inherit fromImage fromImageName fromImageTag;
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nativeBuildInputs = [ util-linux e2fsprogs jshon rsync jq ];
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} ''
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mkdir disk
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mkfs /dev/${vmTools.hd}
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mount /dev/${vmTools.hd} disk
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cd disk
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if [[ -n "$fromImage" ]]; then
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echo "Unpacking base image..."
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mkdir image
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tar -C image -xpf "$fromImage"
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if [[ -n "$fromImageName" ]] && [[ -n "$fromImageTag" ]]; then
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parentID="$(
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cat "image/manifest.json" |
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jq -r '.[] | select(.RepoTags | contains([$desiredTag])) | rtrimstr(".json")' \
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--arg desiredTag "$fromImageName:$fromImageTag"
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)"
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else
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echo "From-image name or tag wasn't set. Reading the first ID."
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parentID="$(cat "image/manifest.json" | jq -r '.[0].Config | rtrimstr(".json")')"
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fi
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cat ./image/manifest.json | jq -r '.[0].Layers | .[]' > layer-list
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else
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touch layer-list
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fi
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# Unpack all of the parent layers into the image.
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lowerdir=""
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extractionID=0
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for layerTar in $(tac layer-list); do
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echo "Unpacking layer $layerTar"
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extractionID=$((extractionID + 1))
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mkdir -p image/$extractionID/layer
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tar -C image/$extractionID/layer -xpf image/$layerTar
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rm image/$layerTar
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find image/$extractionID/layer -name ".wh.*" -exec bash -c 'name="$(basename {}|sed "s/^.wh.//")"; mknod "$(dirname {})/$name" c 0 0; rm {}' \;
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# Get the next lower directory and continue the loop.
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lowerdir=image/$extractionID/layer''${lowerdir:+:}$lowerdir
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done
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mkdir work
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mkdir layer
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mkdir mnt
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${lib.optionalString (preMount != "") ''
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# Execute pre-mount steps
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echo "Executing pre-mount steps..."
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${preMount}
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''}
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if [ -n "$lowerdir" ]; then
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mount -t overlay overlay -olowerdir=$lowerdir,workdir=work,upperdir=layer mnt
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else
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mount --bind layer mnt
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fi
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${lib.optionalString (postMount != "") ''
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# Execute post-mount steps
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echo "Executing post-mount steps..."
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${postMount}
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''}
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umount mnt
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(
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cd layer
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cmd='name="$(basename {})"; touch "$(dirname {})/.wh.$name"; rm "{}"'
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find . -type c -exec bash -c "$cmd" \;
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)
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${postUmount}
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'');
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in
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runCommand name {} ''
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mkdir -p $out
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cd ${result}
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cp layer.tar json VERSION $out
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'';
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exportImage = { name ? fromImage.name, fromImage, fromImageName ? null, fromImageTag ? null, diskSize ? 1024 }:
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runWithOverlay {
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inherit name fromImage fromImageName fromImageTag diskSize;
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postMount = ''
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echo "Packing raw image..."
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tar -C mnt --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" -cf $out .
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'';
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};
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# Create an executable shell script which has the coreutils in its
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# PATH. Since root scripts are executed in a blank environment, even
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# things like `ls` or `echo` will be missing.
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shellScript = name: text:
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writeScript name ''
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#!${runtimeShell}
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set -e
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export PATH=${coreutils}/bin:/bin
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${text}
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'';
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# Create a "layer" (set of files).
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mkPureLayer = {
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# Name of the layer
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name,
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# JSON containing configuration and metadata for this layer.
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baseJson,
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# Files to add to the layer.
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contents ? null,
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# When copying the contents into the image, preserve symlinks to
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# directories (see `rsync -K`). Otherwise, transform those symlinks
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# into directories.
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keepContentsDirlinks ? false,
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# Additional commands to run on the layer before it is tar'd up.
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extraCommands ? "", uid ? 0, gid ? 0
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}:
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runCommand "docker-layer-${name}" {
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inherit baseJson contents extraCommands;
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nativeBuildInputs = [ jshon rsync tarsum ];
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}
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''
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mkdir layer
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if [[ -n "$contents" ]]; then
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echo "Adding contents..."
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for item in $contents; do
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echo "Adding $item"
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rsync -a${if keepContentsDirlinks then "K" else "k"} --chown=0:0 $item/ layer/
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done
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else
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echo "No contents to add to layer."
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fi
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chmod ug+w layer
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if [[ -n "$extraCommands" ]]; then
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(cd layer; eval "$extraCommands")
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fi
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# Tar up the layer and throw it into 'layer.tar'.
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echo "Packing layer..."
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mkdir $out
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tarhash=$(tar -C layer --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" --owner=${toString uid} --group=${toString gid} -cf - . | tee -p $out/layer.tar | tarsum)
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# Add a 'checksum' field to the JSON, with the value set to the
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# checksum of the tarball.
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cat ${baseJson} | jshon -s "$tarhash" -i checksum > $out/json
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# Indicate to docker that we're using schema version 1.0.
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echo -n "1.0" > $out/VERSION
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echo "Finished building layer '${name}'"
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'';
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# Make a "root" layer; required if we need to execute commands as a
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# privileged user on the image. The commands themselves will be
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# performed in a virtual machine sandbox.
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mkRootLayer = {
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# Name of the image.
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name,
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# Script to run as root. Bash.
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runAsRoot,
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# Files to add to the layer. If null, an empty layer will be created.
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contents ? null,
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# When copying the contents into the image, preserve symlinks to
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# directories (see `rsync -K`). Otherwise, transform those symlinks
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# into directories.
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keepContentsDirlinks ? false,
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# JSON containing configuration and metadata for this layer.
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baseJson,
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# Existing image onto which to append the new layer.
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fromImage ? null,
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# Name of the image we're appending onto.
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fromImageName ? null,
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# Tag of the image we're appending onto.
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fromImageTag ? null,
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# How much disk to allocate for the temporary virtual machine.
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diskSize ? 1024,
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# Commands (bash) to run on the layer; these do not require sudo.
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extraCommands ? ""
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}:
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# Generate an executable script from the `runAsRoot` text.
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let
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runAsRootScript = shellScript "run-as-root.sh" runAsRoot;
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extraCommandsScript = shellScript "extra-commands.sh" extraCommands;
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in runWithOverlay {
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name = "docker-layer-${name}";
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inherit fromImage fromImageName fromImageTag diskSize;
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preMount = lib.optionalString (contents != null && contents != []) ''
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echo "Adding contents..."
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for item in ${toString contents}; do
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echo "Adding $item..."
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rsync -a${if keepContentsDirlinks then "K" else "k"} --chown=0:0 $item/ layer/
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done
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chmod ug+w layer
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'';
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postMount = ''
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mkdir -p mnt/{dev,proc,sys} mnt${storeDir}
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# Mount /dev, /sys and the nix store as shared folders.
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mount --rbind /dev mnt/dev
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mount --rbind /sys mnt/sys
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mount --rbind ${storeDir} mnt${storeDir}
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# Execute the run as root script. See 'man unshare' for
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# details on what's going on here; basically this command
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# means that the runAsRootScript will be executed in a nearly
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# completely isolated environment.
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unshare -imnpuf --mount-proc chroot mnt ${runAsRootScript}
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# Unmount directories and remove them.
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umount -R mnt/dev mnt/sys mnt${storeDir}
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rmdir --ignore-fail-on-non-empty \
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mnt/dev mnt/proc mnt/sys mnt${storeDir} \
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mnt$(dirname ${storeDir})
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'';
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postUmount = ''
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(cd layer; ${extraCommandsScript})
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echo "Packing layer..."
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mkdir -p $out
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tarhash=$(tar -C layer --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" -cf - . |
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tee -p $out/layer.tar |
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${tarsum}/bin/tarsum)
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cat ${baseJson} | jshon -s "$tarhash" -i checksum > $out/json
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# Indicate to docker that we're using schema version 1.0.
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echo -n "1.0" > $out/VERSION
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echo "Finished building layer '${name}'"
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'';
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};
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buildLayeredImage = {name, ...}@args:
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let
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stream = streamLayeredImage args;
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|
in
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runCommand "${name}.tar.gz" {
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inherit (stream) imageName;
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passthru = { inherit (stream) imageTag; };
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nativeBuildInputs = [ pigz ];
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} "${stream} | pigz -nT > $out";
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|
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# 1. extract the base image
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# 2. create the layer
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# 3. add layer deps to the layer itself, diffing with the base image
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# 4. compute the layer id
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# 5. put the layer in the image
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# 6. repack the image
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buildImage = args@{
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# Image name.
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name,
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# Image tag, when null then the nix output hash will be used.
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tag ? null,
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|
# Parent image, to append to.
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fromImage ? null,
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# Name of the parent image; will be read from the image otherwise.
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|
fromImageName ? null,
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|
# Tag of the parent image; will be read from the image otherwise.
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|
fromImageTag ? null,
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|
# Files to put on the image (a nix store path or list of paths).
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|
contents ? null,
|
|
# When copying the contents into the image, preserve symlinks to
|
|
# directories (see `rsync -K`). Otherwise, transform those symlinks
|
|
# into directories.
|
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keepContentsDirlinks ? false,
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|
# Docker config; e.g. what command to run on the container.
|
|
config ? null,
|
|
# Optional bash script to run on the files prior to fixturizing the layer.
|
|
extraCommands ? "", uid ? 0, gid ? 0,
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# Optional bash script to run as root on the image when provisioning.
|
|
runAsRoot ? null,
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|
# Size of the virtual machine disk to provision when building the image.
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|
diskSize ? 1024,
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# Time of creation of the image.
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|
created ? "1970-01-01T00:00:01Z",
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}:
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let
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|
baseName = baseNameOf name;
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|
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# Create a JSON blob of the configuration. Set the date to unix zero.
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|
baseJson = let
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|
pure = writeText "${baseName}-config.json" (builtins.toJSON {
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|
inherit created config;
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|
architecture = defaultArch;
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|
os = "linux";
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|
});
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|
impure = runCommand "${baseName}-config.json"
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|
{ nativeBuildInputs = [ jq ]; }
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|
''
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jq ".created = \"$(TZ=utc date --iso-8601="seconds")\"" ${pure} > $out
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|
'';
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in if created == "now" then impure else pure;
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|
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layer =
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|
if runAsRoot == null
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|
then mkPureLayer {
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|
name = baseName;
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|
inherit baseJson contents keepContentsDirlinks extraCommands uid gid;
|
|
} else mkRootLayer {
|
|
name = baseName;
|
|
inherit baseJson fromImage fromImageName fromImageTag
|
|
contents keepContentsDirlinks runAsRoot diskSize
|
|
extraCommands;
|
|
};
|
|
result = runCommand "docker-image-${baseName}.tar.gz" {
|
|
nativeBuildInputs = [ jshon pigz coreutils findutils jq moreutils ];
|
|
# Image name and tag must be lowercase
|
|
imageName = lib.toLower name;
|
|
imageTag = if tag == null then "" else lib.toLower tag;
|
|
inherit fromImage baseJson;
|
|
layerClosure = writeReferencesToFile layer;
|
|
passthru.buildArgs = args;
|
|
passthru.layer = layer;
|
|
passthru.imageTag =
|
|
if tag != null
|
|
then lib.toLower tag
|
|
else
|
|
lib.head (lib.strings.splitString "-" (baseNameOf result.outPath));
|
|
# Docker can't be made to run darwin binaries
|
|
meta.badPlatforms = lib.platforms.darwin;
|
|
} ''
|
|
${lib.optionalString (tag == null) ''
|
|
outName="$(basename "$out")"
|
|
outHash=$(echo "$outName" | cut -d - -f 1)
|
|
|
|
imageTag=$outHash
|
|
''}
|
|
|
|
# Print tar contents:
|
|
# 1: Interpreted as relative to the root directory
|
|
# 2: With no trailing slashes on directories
|
|
# This is useful for ensuring that the output matches the
|
|
# values generated by the "find" command
|
|
ls_tar() {
|
|
for f in $(tar -tf $1 | xargs realpath -ms --relative-to=.); do
|
|
if [[ "$f" != "." ]]; then
|
|
echo "/$f"
|
|
fi
|
|
done
|
|
}
|
|
|
|
mkdir image
|
|
touch baseFiles
|
|
baseEnvs='[]'
|
|
if [[ -n "$fromImage" ]]; then
|
|
echo "Unpacking base image..."
|
|
tar -C image -xpf "$fromImage"
|
|
|
|
# Store the layers and the environment variables from the base image
|
|
cat ./image/manifest.json | jq -r '.[0].Layers | .[]' > layer-list
|
|
configName="$(cat ./image/manifest.json | jq -r '.[0].Config')"
|
|
baseEnvs="$(cat "./image/$configName" | jq '.config.Env // []')"
|
|
|
|
# Extract the parentID from the manifest
|
|
if [[ -n "$fromImageName" ]] && [[ -n "$fromImageTag" ]]; then
|
|
parentID="$(
|
|
cat "image/manifest.json" |
|
|
jq -r '.[] | select(.RepoTags | contains([$desiredTag])) | rtrimstr(".json")' \
|
|
--arg desiredTag "$fromImageName:$fromImageTag"
|
|
)"
|
|
else
|
|
echo "From-image name or tag wasn't set. Reading the first ID."
|
|
parentID="$(cat "image/manifest.json" | jq -r '.[0].Config | rtrimstr(".json")')"
|
|
fi
|
|
|
|
# Otherwise do not import the base image configuration and manifest
|
|
chmod a+w image image/*.json
|
|
rm -f image/*.json
|
|
|
|
for l in image/*/layer.tar; do
|
|
ls_tar $l >> baseFiles
|
|
done
|
|
else
|
|
touch layer-list
|
|
fi
|
|
|
|
chmod -R ug+rw image
|
|
|
|
mkdir temp
|
|
cp ${layer}/* temp/
|
|
chmod ug+w temp/*
|
|
|
|
for dep in $(cat $layerClosure); do
|
|
find $dep >> layerFiles
|
|
done
|
|
|
|
echo "Adding layer..."
|
|
# Record the contents of the tarball with ls_tar.
|
|
ls_tar temp/layer.tar >> baseFiles
|
|
|
|
# Append nix/store directory to the layer so that when the layer is loaded in the
|
|
# image /nix/store has read permissions for non-root users.
|
|
# nix/store is added only if the layer has /nix/store paths in it.
|
|
if [ $(wc -l < $layerClosure) -gt 1 ] && [ $(grep -c -e "^/nix/store$" baseFiles) -eq 0 ]; then
|
|
mkdir -p nix/store
|
|
chmod -R 555 nix
|
|
echo "./nix" >> layerFiles
|
|
echo "./nix/store" >> layerFiles
|
|
fi
|
|
|
|
# Get the files in the new layer which were *not* present in
|
|
# the old layer, and record them as newFiles.
|
|
comm <(sort -n baseFiles|uniq) \
|
|
<(sort -n layerFiles|uniq|grep -v ${layer}) -1 -3 > newFiles
|
|
# Append the new files to the layer.
|
|
tar -rpf temp/layer.tar --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" \
|
|
--owner=0 --group=0 --no-recursion --files-from newFiles
|
|
|
|
echo "Adding meta..."
|
|
|
|
# If we have a parentID, add it to the json metadata.
|
|
if [[ -n "$parentID" ]]; then
|
|
cat temp/json | jshon -s "$parentID" -i parent > tmpjson
|
|
mv tmpjson temp/json
|
|
fi
|
|
|
|
# Take the sha256 sum of the generated json and use it as the layer ID.
|
|
# Compute the size and add it to the json under the 'Size' field.
|
|
layerID=$(sha256sum temp/json|cut -d ' ' -f 1)
|
|
size=$(stat --printf="%s" temp/layer.tar)
|
|
cat temp/json | jshon -s "$layerID" -i id -n $size -i Size > tmpjson
|
|
mv tmpjson temp/json
|
|
|
|
# Use the temp folder we've been working on to create a new image.
|
|
mv temp image/$layerID
|
|
|
|
# Add the new layer ID to the end of the layer list
|
|
(
|
|
cat layer-list
|
|
# originally this used `sed -i "1i$layerID" layer-list`, but
|
|
# would fail if layer-list was completely empty.
|
|
echo "$layerID/layer.tar"
|
|
) | sponge layer-list
|
|
|
|
# Create image json and image manifest
|
|
imageJson=$(cat ${baseJson} | jq '.config.Env = $baseenv + .config.Env' --argjson baseenv "$baseEnvs")
|
|
imageJson=$(echo "$imageJson" | jq ". + {\"rootfs\": {\"diff_ids\": [], \"type\": \"layers\"}}")
|
|
manifestJson=$(jq -n "[{\"RepoTags\":[\"$imageName:$imageTag\"]}]")
|
|
|
|
for layerTar in $(cat ./layer-list); do
|
|
layerChecksum=$(sha256sum image/$layerTar | cut -d ' ' -f1)
|
|
imageJson=$(echo "$imageJson" | jq ".history |= . + [{\"created\": \"$(jq -r .created ${baseJson})\"}]")
|
|
# diff_ids order is from the bottom-most to top-most layer
|
|
imageJson=$(echo "$imageJson" | jq ".rootfs.diff_ids |= . + [\"sha256:$layerChecksum\"]")
|
|
manifestJson=$(echo "$manifestJson" | jq ".[0].Layers |= . + [\"$layerTar\"]")
|
|
done
|
|
|
|
imageJsonChecksum=$(echo "$imageJson" | sha256sum | cut -d ' ' -f1)
|
|
echo "$imageJson" > "image/$imageJsonChecksum.json"
|
|
manifestJson=$(echo "$manifestJson" | jq ".[0].Config = \"$imageJsonChecksum.json\"")
|
|
echo "$manifestJson" > image/manifest.json
|
|
|
|
# Store the json under the name image/repositories.
|
|
jshon -n object \
|
|
-n object -s "$layerID" -i "$imageTag" \
|
|
-i "$imageName" > image/repositories
|
|
|
|
# Make the image read-only.
|
|
chmod -R a-w image
|
|
|
|
echo "Cooking the image..."
|
|
tar -C image --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" --owner=0 --group=0 --xform s:'^./':: -c . | pigz -nT > $out
|
|
|
|
echo "Finished."
|
|
'';
|
|
|
|
in
|
|
result;
|
|
|
|
# Provide a /etc/passwd and /etc/group that contain root and nobody.
|
|
# Useful when packaging binaries that insist on using nss to look up
|
|
# username/groups (like nginx).
|
|
# /bin/sh is fine to not exist, and provided by another shim.
|
|
fakeNss = symlinkJoin {
|
|
name = "fake-nss";
|
|
paths = [
|
|
(writeTextDir "etc/passwd" ''
|
|
root:x:0:0:root user:/var/empty:/bin/sh
|
|
nobody:x:65534:65534:nobody:/var/empty:/bin/sh
|
|
'')
|
|
(writeTextDir "etc/group" ''
|
|
root:x:0:
|
|
nobody:x:65534:
|
|
'')
|
|
(runCommand "var-empty" {} ''
|
|
mkdir -p $out/var/empty
|
|
'')
|
|
];
|
|
};
|
|
|
|
# This provides /bin/sh, pointing to bashInteractive.
|
|
binSh = runCommand "bin-sh" {} ''
|
|
mkdir -p $out/bin
|
|
ln -s ${bashInteractive}/bin/bash $out/bin/sh
|
|
'';
|
|
|
|
# Build an image and populate its nix database with the provided
|
|
# contents. The main purpose is to be able to use nix commands in
|
|
# the container.
|
|
# Be careful since this doesn't work well with multilayer.
|
|
buildImageWithNixDb = args@{ contents ? null, extraCommands ? "", ... }: (
|
|
buildImage (args // {
|
|
extraCommands = (mkDbExtraCommand contents) + extraCommands;
|
|
})
|
|
);
|
|
|
|
buildLayeredImageWithNixDb = args@{ contents ? null, extraCommands ? "", ... }: (
|
|
buildLayeredImage (args // {
|
|
extraCommands = (mkDbExtraCommand contents) + extraCommands;
|
|
})
|
|
);
|
|
|
|
streamLayeredImage = {
|
|
# Image Name
|
|
name,
|
|
# Image tag, the Nix's output hash will be used if null
|
|
tag ? null,
|
|
# Files to put on the image (a nix store path or list of paths).
|
|
contents ? [],
|
|
# Docker config; e.g. what command to run on the container.
|
|
config ? {},
|
|
# Time of creation of the image. Passing "now" will make the
|
|
# created date be the time of building.
|
|
created ? "1970-01-01T00:00:01Z",
|
|
# Optional bash script to run on the files prior to fixturizing the layer.
|
|
extraCommands ? "",
|
|
# We pick 100 to ensure there is plenty of room for extension. I
|
|
# believe the actual maximum is 128.
|
|
maxLayers ? 100
|
|
}:
|
|
assert
|
|
(lib.assertMsg (maxLayers > 1)
|
|
"the maxLayers argument of dockerTools.buildLayeredImage function must be greather than 1 (current value: ${toString maxLayers})");
|
|
let
|
|
streamScript = writePython3 "stream" {} ./stream_layered_image.py;
|
|
baseJson = writeText "${name}-base.json" (builtins.toJSON {
|
|
inherit config;
|
|
architecture = defaultArch;
|
|
os = "linux";
|
|
});
|
|
|
|
contentsList = if builtins.isList contents then contents else [ contents ];
|
|
|
|
# We store the customisation layer as a tarball, to make sure that
|
|
# things like permissions set on 'extraCommands' are not overriden
|
|
# by Nix. Then we precompute the sha256 for performance.
|
|
customisationLayer = symlinkJoin {
|
|
name = "${name}-customisation-layer";
|
|
paths = contentsList;
|
|
inherit extraCommands;
|
|
postBuild = ''
|
|
mv $out old_out
|
|
(cd old_out; eval "$extraCommands" )
|
|
|
|
mkdir $out
|
|
|
|
tar \
|
|
--owner 0 --group 0 --mtime "@$SOURCE_DATE_EPOCH" \
|
|
--hard-dereference \
|
|
-C old_out \
|
|
-cf $out/layer.tar .
|
|
|
|
sha256sum $out/layer.tar \
|
|
| cut -f 1 -d ' ' \
|
|
> $out/checksum
|
|
'';
|
|
};
|
|
|
|
closureRoots = [ baseJson ] ++ contentsList;
|
|
overallClosure = writeText "closure" (lib.concatStringsSep " " closureRoots);
|
|
|
|
# These derivations are only created as implementation details of docker-tools,
|
|
# so they'll be excluded from the created images.
|
|
unnecessaryDrvs = [ baseJson overallClosure ];
|
|
|
|
conf = runCommand "${name}-conf.json" {
|
|
inherit maxLayers created;
|
|
imageName = lib.toLower name;
|
|
passthru.imageTag =
|
|
if tag != null
|
|
then tag
|
|
else
|
|
lib.head (lib.strings.splitString "-" (baseNameOf conf.outPath));
|
|
paths = buildPackages.referencesByPopularity overallClosure;
|
|
nativeBuildInputs = [ jq ];
|
|
} ''
|
|
${if (tag == null) then ''
|
|
outName="$(basename "$out")"
|
|
outHash=$(echo "$outName" | cut -d - -f 1)
|
|
|
|
imageTag=$outHash
|
|
'' else ''
|
|
imageTag="${tag}"
|
|
''}
|
|
|
|
# convert "created" to iso format
|
|
if [[ "$created" != "now" ]]; then
|
|
created="$(date -Iseconds -d "$created")"
|
|
fi
|
|
|
|
paths() {
|
|
cat $paths ${lib.concatMapStringsSep " "
|
|
(path: "| (grep -v ${path} || true)")
|
|
unnecessaryDrvs}
|
|
}
|
|
|
|
# Create $maxLayers worth of Docker Layers, one layer per store path
|
|
# unless there are more paths than $maxLayers. In that case, create
|
|
# $maxLayers-1 for the most popular layers, and smush the remainaing
|
|
# store paths in to one final layer.
|
|
#
|
|
# The following code is fiddly w.r.t. ensuring every layer is
|
|
# created, and that no paths are missed. If you change the
|
|
# following lines, double-check that your code behaves properly
|
|
# when the number of layers equals:
|
|
# maxLayers-1, maxLayers, and maxLayers+1, 0
|
|
store_layers="$(
|
|
paths |
|
|
jq -sR '
|
|
rtrimstr("\n") | split("\n")
|
|
| (.[:$maxLayers-1] | map([.])) + [ .[$maxLayers-1:] ]
|
|
| map(select(length > 0))
|
|
' \
|
|
--argjson maxLayers "$(( maxLayers - 1 ))" # one layer will be taken up by the customisation layer
|
|
)"
|
|
|
|
cat ${baseJson} | jq '
|
|
. + {
|
|
"store_layers": $store_layers,
|
|
"customisation_layer", $customisation_layer,
|
|
"repo_tag": $repo_tag,
|
|
"created": $created
|
|
}
|
|
' --argjson store_layers "$store_layers" \
|
|
--arg customisation_layer ${customisationLayer} \
|
|
--arg repo_tag "$imageName:$imageTag" \
|
|
--arg created "$created" |
|
|
tee $out
|
|
'';
|
|
result = runCommand "stream-${name}" {
|
|
inherit (conf) imageName;
|
|
passthru = {
|
|
inherit (conf) imageTag;
|
|
|
|
# Distinguish tarballs and exes at the Nix level so functions that
|
|
# take images can know in advance how the image is supposed to be used.
|
|
isExe = true;
|
|
};
|
|
nativeBuildInputs = [ makeWrapper ];
|
|
} ''
|
|
makeWrapper ${streamScript} $out --add-flags ${conf}
|
|
'';
|
|
in result;
|
|
}
|