mirror of
https://github.com/NixOS/nixpkgs.git
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6dab1b50a6
This is useful when buildLayeredImage is called in a generic way that should allow simple (base) images to be built, which may not reference any store paths.
898 lines
30 KiB
Nix
898 lines
30 KiB
Nix
{
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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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moreutils,
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nix,
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pigz,
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referencesByPopularity,
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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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utillinux,
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vmTools,
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writeReferencesToFile,
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writeScript,
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writeText,
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}:
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# WARNING: this API is unstable and may be subject to backwards-incompatible changes in the future.
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rec {
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examples = callPackage ./examples.nix {
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inherit buildImage 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 ? buildPackages.go.GOARCH
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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 --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 = [ utillinux 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 the image name isn't set, read it from the image repository json.
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if [[ -z "$fromImageName" ]]; then
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fromImageName=$(jshon -k < image/repositories | head -n 1)
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echo "From-image name wasn't set. Read $fromImageName."
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fi
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# If the tag isn't set, use the name as an index into the json
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# and read the first key found.
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if [[ -z "$fromImageTag" ]]; then
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fromImageTag=$(jshon -e $fromImageName -k < image/repositories \
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| head -n1)
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echo "From-image tag wasn't set. Read $fromImageTag."
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fi
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# Use the name and tag to get the parent ID field.
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parentID=$(jshon -e $fromImageName -e $fromImageTag -u \
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< image/repositories)
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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 $maxLayers worth of Docker Layers, one layer per store path
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# unless there are more paths than $maxLayers. In that case, create
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# $maxLayers-1 for the most popular layers, and smush the remainaing
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# store paths in to one final layer.
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#
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# NOTE: the `closures` parameter is a list of closures to include.
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# The TOP LEVEL store paths themselves will never be present in the
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# resulting image. At this time (2019-12-16) none of these layers
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# are appropriate to include, as they are all created as
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# implementation details of dockerTools.
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mkManyPureLayers = {
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name,
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# Files to add to the layer.
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closures,
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configJson,
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# Docker has a 125-layer maximum, we pick 100 to ensure there is
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# plenty of room for extension.
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# https://github.com/moby/moby/blob/b3e9f7b13b0f0c414fa6253e1f17a86b2cff68b5/layer/layer_store.go#L23-L26
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maxLayers ? 100
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}:
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let
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storePathToLayer = substituteAll
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{ shell = runtimeShell;
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isExecutable = true;
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src = ./store-path-to-layer.sh;
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};
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overallClosure = writeText "closure" (lib.concatStringsSep " " closures);
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in
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runCommand "${name}-granular-docker-layers" {
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inherit maxLayers;
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paths = referencesByPopularity overallClosure;
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nativeBuildInputs = [ jshon rsync tarsum moreutils ];
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enableParallelBuilding = true;
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}
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''
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mkdir layers
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# Delete impurities for store path layers, so they don't get
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# shared and taint other projects.
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cat ${configJson} \
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| jshon -d config \
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| jshon -s "1970-01-01T00:00:01Z" -i created > generic.json
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# WARNING!
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# The following code is fiddly w.r.t. ensuring every layer is
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# created, and that no paths are missed. If you change the
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# following head and tail call lines, double-check that your
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# code behaves properly when the number of layers equals:
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# maxLayers-1, maxLayers, and maxLayers+1, 0
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paths() {
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cat $paths ${lib.concatMapStringsSep " " (path: "| (grep -v ${path} || true)") (closures ++ [ overallClosure ])}
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}
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paths | head -n $((maxLayers - 1)) | cat -n | xargs -r -P$NIX_BUILD_CORES -n2 ${storePathToLayer}
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if [ $(paths | wc -l) -ge $maxLayers ]; then
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paths | tail -n+$maxLayers | xargs ${storePathToLayer} $maxLayers
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fi
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echo "Finished building layer '$name'"
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mv ./layers $out
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'';
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# Create a "Customisation" layer which adds symlinks at the root of
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# the image to the root paths of the closure. Also add the config
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# data like what command to run and the environment to run it in.
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mkCustomisationLayer = {
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name,
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# Files to add to the layer.
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contents,
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baseJson,
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extraCommands,
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uid ? 0, gid ? 0,
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}:
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runCommand "${name}-customisation-layer" {
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nativeBuildInputs = [ jshon rsync tarsum ];
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inherit extraCommands;
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}
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''
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cp -r ${contents}/ ./layer
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if [[ -n $extraCommands ]]; then
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chmod ug+w layer
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(cd layer; eval "$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 $out
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tar --transform='s|^\./||' -C layer --sort=name --mtime="@$SOURCE_DATE_EPOCH" --owner=${toString uid} --group=${toString gid} -cf $out/layer.tar .
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# Compute a checksum of the tarball.
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echo "Computing layer checksum..."
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tarhash=$(tarsum < $out/layer.tar)
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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" > $out/VERSION
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'';
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# Create a "layer" (set of files).
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mkPureLayer = {
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# Name of the layer
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name,
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# JSON containing configuration and metadata for this layer.
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baseJson,
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# Files to add to the layer.
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contents ? null,
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# When copying the contents into the image, preserve symlinks to
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# directories (see `rsync -K`). Otherwise, transform those symlinks
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# into directories.
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keepContentsDirlinks ? false,
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# Additional commands to run on the layer before it is tar'd up.
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extraCommands ? "", uid ? 0, gid ? 0
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}:
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runCommand "docker-layer-${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 $out
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tar -C layer --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" --owner=${toString uid} --group=${toString gid} -cf $out/layer.tar .
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# Compute a checksum of the tarball.
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echo "Computing layer checksum..."
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tarhash=$(tarsum < $out/layer.tar)
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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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|
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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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|
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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 $out
|
|
tar -C layer --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" -cf $out/layer.tar .
|
|
|
|
# Compute the tar checksum and add it to the output json.
|
|
echo "Computing checksum..."
|
|
tarhash=$(${tarsum}/bin/tarsum < $out/layer.tar)
|
|
cat ${baseJson} | jshon -s "$tarhash" -i checksum > $out/json
|
|
# Indicate to docker that we're using schema version 1.0.
|
|
echo -n "1.0" > $out/VERSION
|
|
|
|
echo "Finished building layer '${name}'"
|
|
'';
|
|
};
|
|
|
|
buildLayeredImage = {
|
|
# 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 ? "", uid ? 0, gid ? 0,
|
|
# 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: ${toString maxLayers})");
|
|
let
|
|
baseName = baseNameOf name;
|
|
contentsEnv = symlinkJoin {
|
|
name = "bulk-layers";
|
|
paths = if builtins.isList contents
|
|
then contents
|
|
else [ contents ];
|
|
};
|
|
|
|
configJson = let
|
|
pure = writeText "${baseName}-config.json" (builtins.toJSON {
|
|
inherit created config;
|
|
architecture = buildPackages.go.GOARCH;
|
|
os = "linux";
|
|
});
|
|
impure = runCommand "${baseName}-standard-dynamic-date.json"
|
|
{ nativeBuildInputs = [ jq ]; }
|
|
''
|
|
jq ".created = \"$(TZ=utc date --iso-8601="seconds")\"" ${pure} > $out
|
|
'';
|
|
in if created == "now" then impure else pure;
|
|
|
|
bulkLayers = mkManyPureLayers {
|
|
name = baseName;
|
|
closures = [ contentsEnv configJson ];
|
|
# One layer will be taken up by the customisationLayer, so
|
|
# take up one less.
|
|
maxLayers = maxLayers - 1;
|
|
inherit configJson;
|
|
};
|
|
customisationLayer = mkCustomisationLayer {
|
|
name = baseName;
|
|
contents = contentsEnv;
|
|
baseJson = configJson;
|
|
inherit uid gid extraCommands;
|
|
};
|
|
result = runCommand "docker-image-${baseName}.tar.gz" {
|
|
nativeBuildInputs = [ jshon pigz coreutils findutils jq ];
|
|
# Image name and tag must be lowercase
|
|
imageName = lib.toLower name;
|
|
baseJson = configJson;
|
|
passthru.imageTag =
|
|
if tag == null
|
|
then lib.head (lib.splitString "-" (lib.last (lib.splitString "/" result)))
|
|
else lib.toLower tag;
|
|
# Docker can't be made to run darwin binaries
|
|
meta.badPlatforms = lib.platforms.darwin;
|
|
} ''
|
|
${if (tag == null) then ''
|
|
outName="$(basename "$out")"
|
|
outHash=$(echo "$outName" | cut -d - -f 1)
|
|
|
|
imageTag=$outHash
|
|
'' else ''
|
|
imageTag="${tag}"
|
|
''}
|
|
|
|
find ${bulkLayers} -mindepth 1 -maxdepth 1 | sort -t/ -k5 -n > layer-list
|
|
echo ${customisationLayer} >> layer-list
|
|
|
|
mkdir image
|
|
imageJson=$(cat ${configJson} | jq ". + {\"rootfs\": {\"diff_ids\": [], \"type\": \"layers\"}}")
|
|
manifestJson=$(jq -n "[{\"RepoTags\":[\"$imageName:$imageTag\"]}]")
|
|
for layer in $(cat layer-list); do
|
|
layerChecksum=$(sha256sum $layer/layer.tar | cut -d ' ' -f1)
|
|
layerID=$(sha256sum "$layer/json" | cut -d ' ' -f 1)
|
|
ln -s "$layer" "./image/$layerID"
|
|
|
|
manifestJson=$(echo "$manifestJson" | jq ".[0].Layers |= . + [\"$layerID/layer.tar\"]")
|
|
imageJson=$(echo "$imageJson" | jq ".history |= . + [{\"created\": \"$(jq -r .created ${configJson})\"}]")
|
|
imageJson=$(echo "$imageJson" | jq ".rootfs.diff_ids |= . + [\"sha256:$layerChecksum\"]")
|
|
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
|
|
|
|
jshon -n object \
|
|
-n object -s "$layerID" -i "$imageTag" \
|
|
-i "$imageName" > image/repositories
|
|
|
|
echo "Cooking the image..."
|
|
# tar exits with an exit code of 1 if files changed while it was
|
|
# reading them. It considers a change in the number of hard links
|
|
# to be a "change", which can cause this to fail if images are being
|
|
# built concurrently and the auto-optimise-store nix option is turned on.
|
|
# Since the contents of these files will not change, we can reasonably
|
|
# ignore this exit code.
|
|
set +e
|
|
tar -C image --dereference --hard-dereference --sort=name \
|
|
--mtime="@$SOURCE_DATE_EPOCH" --owner=0 --group=0 \
|
|
--mode=a-w --xform s:'^./':: --use-compress-program='pigz -nT' \
|
|
--warning=no-file-changed -cf $out .
|
|
RET=$?
|
|
if [ $RET -ne 0 ] && [ $RET -ne 1 ]; then
|
|
exit $RET
|
|
fi
|
|
set -e
|
|
|
|
echo "Finished."
|
|
'';
|
|
|
|
in
|
|
result;
|
|
|
|
# 1. extract the base image
|
|
# 2. create the layer
|
|
# 3. add layer deps to the layer itself, diffing with the base image
|
|
# 4. compute the layer id
|
|
# 5. put the layer in the image
|
|
# 6. repack the image
|
|
buildImage = args@{
|
|
# Image name.
|
|
name,
|
|
# Image tag, when null then the nix output hash will be used.
|
|
tag ? null,
|
|
# Parent image, to append to.
|
|
fromImage ? null,
|
|
# Name of the parent image; will be read from the image otherwise.
|
|
fromImageName ? null,
|
|
# Tag of the parent image; will be read from the image otherwise.
|
|
fromImageTag ? null,
|
|
# Files to put on the image (a nix store path or list of paths).
|
|
contents ? null,
|
|
# When copying the contents into the image, preserve symlinks to
|
|
# directories (see `rsync -K`). Otherwise, transform those symlinks
|
|
# into directories.
|
|
keepContentsDirlinks ? false,
|
|
# Docker config; e.g. what command to run on the container.
|
|
config ? null,
|
|
# Optional bash script to run on the files prior to fixturizing the layer.
|
|
extraCommands ? "", uid ? 0, gid ? 0,
|
|
# Optional bash script to run as root on the image when provisioning.
|
|
runAsRoot ? null,
|
|
# Size of the virtual machine disk to provision when building the image.
|
|
diskSize ? 1024,
|
|
# Time of creation of the image.
|
|
created ? "1970-01-01T00:00:01Z",
|
|
}:
|
|
|
|
let
|
|
baseName = baseNameOf name;
|
|
|
|
# Create a JSON blob of the configuration. Set the date to unix zero.
|
|
baseJson = let
|
|
pure = writeText "${baseName}-config.json" (builtins.toJSON {
|
|
inherit created config;
|
|
architecture = buildPackages.go.GOARCH;
|
|
os = "linux";
|
|
});
|
|
impure = runCommand "${baseName}-config.json"
|
|
{ nativeBuildInputs = [ jq ]; }
|
|
''
|
|
jq ".created = \"$(TZ=utc date --iso-8601="seconds")\"" ${pure} > $out
|
|
'';
|
|
in if created == "now" then impure else pure;
|
|
|
|
layer =
|
|
if runAsRoot == null
|
|
then mkPureLayer {
|
|
name = baseName;
|
|
inherit baseJson contents keepContentsDirlinks extraCommands uid gid;
|
|
} else mkRootLayer {
|
|
name = baseName;
|
|
inherit baseJson fromImage fromImageName fromImageTag
|
|
contents keepContentsDirlinks runAsRoot diskSize
|
|
extraCommands;
|
|
};
|
|
result = runCommand "docker-image-${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;
|
|
# 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 "/$f"
|
|
fi
|
|
done
|
|
}
|
|
|
|
mkdir image
|
|
touch baseFiles
|
|
if [[ -n "$fromImage" ]]; then
|
|
echo "Unpacking base image..."
|
|
tar -C image -xpf "$fromImage"
|
|
|
|
cat ./image/manifest.json | jq -r '.[0].Layers | .[]' > layer-list
|
|
|
|
# Do not import the base image configuration and manifest
|
|
chmod a+w image image/*.json
|
|
rm -f image/*.json
|
|
|
|
if [[ -z "$fromImageName" ]]; then
|
|
fromImageName=$(jshon -k < image/repositories|head -n1)
|
|
fi
|
|
if [[ -z "$fromImageTag" ]]; then
|
|
fromImageTag=$(jshon -e $fromImageName -k \
|
|
< image/repositories|head -n1)
|
|
fi
|
|
parentID=$(jshon -e $fromImageName -e $fromImageTag -u \
|
|
< image/repositories)
|
|
|
|
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 ${baseJson} | jq ". + {\"rootfs\": {\"diff_ids\": [], \"type\": \"layers\"}}")
|
|
manifestJson=$(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 > $out
|
|
|
|
echo "Finished."
|
|
'';
|
|
|
|
in
|
|
result;
|
|
|
|
# Build an image and populate its nix database with the provided
|
|
# contents. The main purpose is to be able to use nix commands in
|
|
# the container.
|
|
# Be careful since this doesn't work well with multilayer.
|
|
buildImageWithNixDb = args@{ contents ? null, extraCommands ? "", ... }:
|
|
let contentsList = if builtins.isList contents then contents else [ contents ];
|
|
in buildImage (args // {
|
|
extraCommands = ''
|
|
echo "Generating the nix database..."
|
|
echo "Warning: only the database of the deepest Nix layer is loaded."
|
|
echo " If you want to use nix commands in the container, it would"
|
|
echo " be better to only have one layer that contains a nix store."
|
|
|
|
export NIX_REMOTE=local?root=$PWD
|
|
# A user is required by nix
|
|
# https://github.com/NixOS/nix/blob/9348f9291e5d9e4ba3c4347ea1b235640f54fd79/src/libutil/util.cc#L478
|
|
export USER=nobody
|
|
${nix}/bin/nix-store --load-db < ${closureInfo {rootPaths = contentsList;}}/registration
|
|
|
|
mkdir -p nix/var/nix/gcroots/docker/
|
|
for i in ${lib.concatStringsSep " " contentsList}; do
|
|
ln -s $i nix/var/nix/gcroots/docker/$(basename $i)
|
|
done;
|
|
'' + extraCommands;
|
|
});
|
|
}
|