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nixpkgs-suyu/pkgs/build-support/docker/default.nix
Jörg Thalheim 4911915512 nixos/dockerTools: fixup proot/fakeroot code 
Not sure how this ever worked but tar was trying to archive /proc and /sys, which failed to work.
Since this is never useful for containers to do, we exclude this now in the proot case.
Also fakeroot is not needed when proot is used as it provideds the same feature.
We now cleanly seperate those cases as both are kind of hacks and it's more likely
that the combination will just trigger new bugs.
2023-11-19 08:30:27 +01:00

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{ bashInteractive
, buildPackages
, cacert
, callPackage
, closureInfo
, coreutils
, e2fsprogs
, proot
, fakeNss
, fakeroot
, go
, jq
, jshon
, lib
, makeWrapper
, moreutils
, nix
, nixosTests
, pigz
, rsync
, runCommand
, runtimeShell
, shadow
, skopeo
, storeDir ? builtins.storeDir
, substituteAll
, symlinkJoin
, tarsum
, util-linux
, vmTools
, writeReferencesToFile
, writeScript
, writeShellScriptBin
, writeText
, writeTextDir
, writePython3
}:
let
inherit (lib)
optionals
optionalString
;
inherit (lib)
escapeShellArgs
toList
;
mkDbExtraCommand = contents:
let
contentsList = if builtins.isList contents then contents else [ contents ];
in
''
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
${buildPackages.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 $i)
done;
'';
# The OCI Image specification recommends that configurations use values listed
# in the Go Language document for GOARCH.
# Reference: https://github.com/opencontainers/image-spec/blob/master/config.md#properties
# For the mapping from Nixpkgs system parameters to GOARCH, we can reuse the
# mapping from the go package.
defaultArchitecture = go.GOARCH;
in
rec {
examples = callPackage ./examples.nix {
inherit buildImage buildLayeredImage fakeNss pullImage shadowSetup buildImageWithNixDb streamNixShellImage;
};
tests = {
inherit (nixosTests)
docker-tools
docker-tools-overlay
# requires remote builder
# docker-tools-cross
;
};
pullImage =
let
fixName = name: builtins.replaceStrings [ "/" ":" ] [ "-" "-" ] name;
in
{ imageName
# To find the digest of an image, you can use skopeo:
# see doc/functions.xml
, imageDigest
, sha256
, os ? "linux"
, # Image architecture, defaults to the architecture of the `hostPlatform` when unset
arch ? defaultArchitecture
# This is used to set name to the pulled image
, finalImageName ? imageName
# This used to set a tag to the pulled image
, finalImageTag ? "latest"
# This is used to disable TLS certificate verification, allowing access to http registries on (hopefully) trusted networks
, tlsVerify ? true
, name ? fixName "docker-image-${finalImageName}-${finalImageTag}.tar"
}:
runCommand name
{
inherit imageDigest;
imageName = finalImageName;
imageTag = finalImageTag;
impureEnvVars = lib.fetchers.proxyImpureEnvVars;
outputHashMode = "flat";
outputHashAlgo = "sha256";
outputHash = sha256;
nativeBuildInputs = [ skopeo ];
SSL_CERT_FILE = "${cacert.out}/etc/ssl/certs/ca-bundle.crt";
sourceURL = "docker://${imageName}@${imageDigest}";
destNameTag = "${finalImageName}:${finalImageTag}";
} ''
skopeo \
--insecure-policy \
--tmpdir=$TMPDIR \
--override-os ${os} \
--override-arch ${arch} \
copy \
--src-tls-verify=${lib.boolToString tlsVerify} \
"$sourceURL" "docker-archive://$out:$destNameTag" \
| cat # pipe through cat to force-disable progress bar
'';
# We need to sum layer.tar, not a directory, hence tarsum instead of nix-hash.
# And we cannot untar it, because then we cannot preserve permissions etc.
inherit tarsum; # pkgs.dockerTools.tarsum
# buildEnv creates symlinks to dirs, which is hard to edit inside the overlay VM
mergeDrvs =
{ derivations
, onlyDeps ? false
}:
runCommand "merge-drvs"
{
inherit derivations onlyDeps;
} ''
if [[ -n "$onlyDeps" ]]; then
echo $derivations > $out
exit 0
fi
mkdir $out
for derivation in $derivations; do
echo "Merging $derivation..."
if [[ -d "$derivation" ]]; then
# If it's a directory, copy all of its contents into $out.
cp -drf --preserve=mode -f $derivation/* $out/
else
# Otherwise treat the derivation as a tarball and extract it
# into $out.
tar -C $out -xpf $drv || true
fi
done
'';
# Helper for setting up the base files for managing users and
# groups, only if such files don't exist already. It is suitable for
# being used in a runAsRoot script.
shadowSetup = ''
export PATH=${shadow}/bin:$PATH
mkdir -p /etc/pam.d
if [[ ! -f /etc/passwd ]]; then
echo "root:x:0:0::/root:${runtimeShell}" > /etc/passwd
echo "root:!x:::::::" > /etc/shadow
fi
if [[ ! -f /etc/group ]]; then
echo "root:x:0:" > /etc/group
echo "root:x::" > /etc/gshadow
fi
if [[ ! -f /etc/pam.d/other ]]; then
cat > /etc/pam.d/other <<EOF
account sufficient pam_unix.so
auth sufficient pam_rootok.so
password requisite pam_unix.so nullok yescrypt
session required pam_unix.so
EOF
fi
if [[ ! -f /etc/login.defs ]]; then
touch /etc/login.defs
fi
'';
# Run commands in a virtual machine.
runWithOverlay =
{ name
, fromImage ? null
, fromImageName ? null
, fromImageTag ? null
, diskSize ? 1024
, buildVMMemorySize ? 512
, preMount ? ""
, postMount ? ""
, postUmount ? ""
}:
vmTools.runInLinuxVM (
runCommand name
{
preVM = vmTools.createEmptyImage {
size = diskSize;
fullName = "docker-run-disk";
destination = "./image";
};
inherit fromImage fromImageName fromImageTag;
memSize = buildVMMemorySize;
nativeBuildInputs = [ util-linux e2fsprogs jshon rsync jq ];
} ''
mkdir disk
mkfs /dev/${vmTools.hd}
mount /dev/${vmTools.hd} disk
cd disk
function dedup() {
declare -A seen
while read ln; do
if [[ -z "''${seen["$ln"]:-}" ]]; then
echo "$ln"; seen["$ln"]=1
fi
done
}
if [[ -n "$fromImage" ]]; then
echo "Unpacking base image..."
mkdir image
tar -C image -xpf "$fromImage"
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
# In case of repeated layers, unpack only the last occurrence of each
cat ./image/manifest.json | jq -r '.[0].Layers | .[]' | tac | dedup | tac > layer-list
else
touch layer-list
fi
# Unpack all of the parent layers into the image.
lowerdir=""
extractionID=0
for layerTar in $(cat layer-list); do
echo "Unpacking layer $layerTar"
extractionID=$((extractionID + 1))
mkdir -p image/$extractionID/layer
tar -C image/$extractionID/layer -xpf image/$layerTar
rm image/$layerTar
find image/$extractionID/layer -name ".wh.*" -exec bash -c 'name="$(basename {}|sed "s/^.wh.//")"; mknod "$(dirname {})/$name" c 0 0; rm {}' \;
# Get the next lower directory and continue the loop.
lowerdir=image/$extractionID/layer''${lowerdir:+:}$lowerdir
done
mkdir work
mkdir layer
mkdir mnt
${lib.optionalString (preMount != "") ''
# Execute pre-mount steps
echo "Executing pre-mount steps..."
${preMount}
''}
if [ -n "$lowerdir" ]; then
mount -t overlay overlay -olowerdir=$lowerdir,workdir=work,upperdir=layer mnt
else
mount --bind layer mnt
fi
${lib.optionalString (postMount != "") ''
# Execute post-mount steps
echo "Executing post-mount steps..."
${postMount}
''}
umount mnt
(
cd layer
cmd='name="$(basename {})"; touch "$(dirname {})/.wh.$name"; rm "{}"'
find . -type c -exec bash -c "$cmd" \;
)
${postUmount}
'');
exportImage = { name ? fromImage.name, fromImage, fromImageName ? null, fromImageTag ? null, diskSize ? 1024 }:
runWithOverlay {
inherit name fromImage fromImageName fromImageTag diskSize;
postMount = ''
echo "Packing raw image..."
tar -C mnt --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" -cf $out/layer.tar .
'';
postUmount = ''
mv $out/layer.tar .
rm -rf $out
mv layer.tar $out
'';
};
# Create an executable shell script which has the coreutils in its
# PATH. Since root scripts are executed in a blank environment, even
# things like `ls` or `echo` will be missing.
shellScript = name: text:
writeScript name ''
#!${runtimeShell}
set -e
export PATH=${coreutils}/bin:/bin
${text}
'';
# Create a "layer" (set of files).
mkPureLayer =
{
# Name of the layer
name
, # JSON containing configuration and metadata for this layer.
baseJson
, # Files to add to the layer.
copyToRoot ? null
, # When copying the contents into the image, preserve symlinks to
# directories (see `rsync -K`). Otherwise, transform those symlinks
# into directories.
keepContentsDirlinks ? false
, # Additional commands to run on the layer before it is tar'd up.
extraCommands ? ""
, uid ? 0
, gid ? 0
}:
runCommand "docker-layer-${name}"
{
inherit baseJson extraCommands;
contents = copyToRoot;
nativeBuildInputs = [ jshon rsync tarsum ];
}
''
mkdir layer
if [[ -n "$contents" ]]; then
echo "Adding contents..."
for item in $contents; do
echo "Adding $item"
rsync -a${if keepContentsDirlinks then "K" else "k"} --chown=0:0 $item/ layer/
done
else
echo "No contents to add to layer."
fi
chmod ug+w layer
if [[ -n "$extraCommands" ]]; then
(cd layer; eval "$extraCommands")
fi
# Tar up the layer and throw it into 'layer.tar'.
echo "Packing layer..."
mkdir $out
tarhash=$(tar -C layer --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" --owner=${toString uid} --group=${toString gid} -cf - . | tee -p $out/layer.tar | tarsum)
# Add a 'checksum' field to the JSON, with the value set to the
# checksum of the tarball.
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}'"
'';
# Make a "root" layer; required if we need to execute commands as a
# privileged user on the image. The commands themselves will be
# performed in a virtual machine sandbox.
mkRootLayer =
{
# Name of the image.
name
, # Script to run as root. Bash.
runAsRoot
, # Files to add to the layer. If null, an empty layer will be created.
# To add packages to /bin, use `buildEnv` or similar.
copyToRoot ? null
, # When copying the contents into the image, preserve symlinks to
# directories (see `rsync -K`). Otherwise, transform those symlinks
# into directories.
keepContentsDirlinks ? false
, # JSON containing configuration and metadata for this layer.
baseJson
, # Existing image onto which to append the new layer.
fromImage ? null
, # Name of the image we're appending onto.
fromImageName ? null
, # Tag of the image we're appending onto.
fromImageTag ? null
, # How much disk to allocate for the temporary virtual machine.
diskSize ? 1024
, # How much memory to allocate for the temporary virtual machine.
buildVMMemorySize ? 512
, # Commands (bash) to run on the layer; these do not require sudo.
extraCommands ? ""
}:
# Generate an executable script from the `runAsRoot` text.
let
runAsRootScript = shellScript "run-as-root.sh" runAsRoot;
extraCommandsScript = shellScript "extra-commands.sh" extraCommands;
in
runWithOverlay {
name = "docker-layer-${name}";
inherit fromImage fromImageName fromImageTag diskSize buildVMMemorySize;
preMount = lib.optionalString (copyToRoot != null && copyToRoot != [ ]) ''
echo "Adding contents..."
for item in ${escapeShellArgs (map (c: "${c}") (toList copyToRoot))}; do
echo "Adding $item..."
rsync -a${if keepContentsDirlinks then "K" else "k"} --chown=0:0 $item/ layer/
done
chmod ug+w layer
'';
postMount = ''
mkdir -p mnt/{dev,proc,sys,tmp} mnt${storeDir}
# Mount /dev, /sys and the nix store as shared folders.
mount --rbind /dev mnt/dev
mount --rbind /sys mnt/sys
mount --rbind ${storeDir} mnt${storeDir}
# Execute the run as root script. See 'man unshare' for
# details on what's going on here; basically this command
# means that the runAsRootScript will be executed in a nearly
# completely isolated environment.
#
# Ideally we would use --mount-proc=mnt/proc or similar, but this
# doesn't work. The workaround is to setup proc after unshare.
# See: https://github.com/karelzak/util-linux/issues/648
unshare -imnpuf --mount-proc sh -c 'mount --rbind /proc mnt/proc && chroot mnt ${runAsRootScript}'
# Unmount directories and remove them.
umount -R mnt/dev mnt/sys mnt${storeDir}
rmdir --ignore-fail-on-non-empty \
mnt/dev mnt/proc mnt/sys mnt${storeDir} \
mnt$(dirname ${storeDir})
'';
postUmount = ''
(cd layer; ${extraCommandsScript})
echo "Packing layer..."
mkdir -p $out
tarhash=$(tar -C layer --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" -cf - . |
tee -p $out/layer.tar |
${tarsum}/bin/tarsum)
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 = lib.makeOverridable ({ name, ... }@args:
let
stream = streamLayeredImage args;
in
runCommand "${baseNameOf name}.tar.gz"
{
inherit (stream) imageName;
passthru = { inherit (stream) imageTag; };
nativeBuildInputs = [ pigz ];
} "${stream} | pigz -nTR > $out"
);
# 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 = lib.makeOverridable (
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).
copyToRoot ? 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
, # Image architecture, defaults to the architecture of the `hostPlatform` when unset
architecture ? defaultArchitecture
, # 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
, # Size of the virtual machine memory to provision when building the image.
buildVMMemorySize ? 512
, # Time of creation of the image.
created ? "1970-01-01T00:00:01Z"
, # Deprecated.
contents ? null
,
}:
let
checked =
lib.warnIf (contents != null)
"in docker image ${name}: The contents parameter is deprecated. Change to copyToRoot if the contents are designed to be copied to the root filesystem, such as when you use `buildEnv` or similar between contents and your packages. Use copyToRoot = buildEnv { ... }; or similar if you intend to add packages to /bin."
lib.throwIf (contents != null && copyToRoot != null) "in docker image ${name}: You can not specify both contents and copyToRoot."
;
rootContents = if copyToRoot == null then contents else copyToRoot;
baseName = baseNameOf name;
# Create a JSON blob of the configuration. Set the date to unix zero.
baseJson =
let
pure = writeText "${baseName}-config.json" (builtins.toJSON {
inherit created config architecture;
preferLocalBuild = true;
os = "linux";
});
impure = runCommand "${baseName}-config.json"
{
nativeBuildInputs = [ jq ];
preferLocalBuild = true;
}
''
jq ".created = \"$(TZ=utc date --iso-8601="seconds")\"" ${pure} > $out
'';
in
if created == "now" then impure else pure;
layer =
if runAsRoot == null
then
mkPureLayer
{
name = baseName;
inherit baseJson keepContentsDirlinks extraCommands uid gid;
copyToRoot = rootContents;
} else
mkRootLayer {
name = baseName;
inherit baseJson fromImage fromImageName fromImageTag
keepContentsDirlinks runAsRoot diskSize buildVMMemorySize
extraCommands;
copyToRoot = rootContents;
};
result = runCommand "docker-image-${baseName}.tar.gz"
{
nativeBuildInputs = [ jshon pigz jq moreutils ];
# Image name must be lowercase
imageName = lib.toLower name;
imageTag = lib.optionalString (tag != null) tag;
inherit fromImage baseJson;
layerClosure = writeReferencesToFile layer;
passthru.buildArgs = args;
passthru.layer = layer;
passthru.imageTag =
if tag != null
then tag
else
lib.head (lib.strings.splitString "-" (baseNameOf result.outPath));
} ''
${lib.optionalString (tag == null) ''
outName="$(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 --verbatim-files-from --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 -nTR > $out
echo "Finished."
'';
in
checked result
);
# Merge the tarballs of images built with buildImage into a single
# tarball that contains all images. Running `docker load` on the resulting
# tarball will load the images into the docker daemon.
mergeImages = images: runCommand "merge-docker-images"
{
inherit images;
nativeBuildInputs = [ pigz jq ];
} ''
mkdir image inputs
# Extract images
repos=()
manifests=()
for item in $images; do
name=$(basename $item)
mkdir inputs/$name
tar -I pigz -xf $item -C inputs/$name
if [ -f inputs/$name/repositories ]; then
repos+=(inputs/$name/repositories)
fi
if [ -f inputs/$name/manifest.json ]; then
manifests+=(inputs/$name/manifest.json)
fi
done
# Copy all layers from input images to output image directory
cp -R --update=none inputs/*/* image/
# Merge repositories objects and manifests
jq -s add "''${repos[@]}" > repositories
jq -s add "''${manifests[@]}" > manifest.json
# Replace output image repositories and manifest with merged versions
mv repositories image/repositories
mv manifest.json image/manifest.json
# Create tarball and gzip
tar -C image --hard-dereference --sort=name --mtime="@$SOURCE_DATE_EPOCH" --owner=0 --group=0 --xform s:'^./':: -c . | pigz -nTR > $out
'';
# 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.
inherit fakeNss; # alias
# This provides a /usr/bin/env, for shell scripts using the
# "#!/usr/bin/env executable" shebang.
usrBinEnv = runCommand "usr-bin-env" { } ''
mkdir -p $out/usr/bin
ln -s ${coreutils}/bin/env $out/usr/bin
'';
# This provides /bin/sh, pointing to bashInteractive.
binSh = runCommand "bin-sh" { } ''
mkdir -p $out/bin
ln -s ${bashInteractive}/bin/bash $out/bin/sh
'';
# This provides the ca bundle in common locations
caCertificates = runCommand "ca-certificates" { } ''
mkdir -p $out/etc/ssl/certs $out/etc/pki/tls/certs
# Old NixOS compatibility.
ln -s ${cacert}/etc/ssl/certs/ca-bundle.crt $out/etc/ssl/certs/ca-bundle.crt
# NixOS canonical location + Debian/Ubuntu/Arch/Gentoo compatibility.
ln -s ${cacert}/etc/ssl/certs/ca-bundle.crt $out/etc/ssl/certs/ca-certificates.crt
# CentOS/Fedora compatibility.
ln -s ${cacert}/etc/ssl/certs/ca-bundle.crt $out/etc/pki/tls/certs/ca-bundle.crt
'';
# 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.
# TODO: add the dependencies of the config json.
buildImageWithNixDb = args@{ copyToRoot ? contents, contents ? null, extraCommands ? "", ... }: (
buildImage (args // {
extraCommands = (mkDbExtraCommand copyToRoot) + extraCommands;
})
);
# TODO: add the dependencies of the config json.
buildLayeredImageWithNixDb = args@{ contents ? null, extraCommands ? "", ... }: (
buildLayeredImage (args // {
extraCommands = (mkDbExtraCommand contents) + extraCommands;
})
);
streamLayeredImage = lib.makeOverridable (
{
# Image Name
name
, # Image tag, the Nix's output hash will be used if null
tag ? null
, # Parent image, to append to.
fromImage ? 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 ? { }
, # Image architecture, defaults to the architecture of the `hostPlatform` when unset
architecture ? defaultArchitecture
, # 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 ? ""
, # Optional bash script to run inside fakeroot environment.
# Could be used for changing ownership of files in customisation layer.
fakeRootCommands ? ""
, # Whether to run fakeRootCommands in fakechroot as well, so that they
# appear to run inside the image, but have access to the normal Nix store.
# Perhaps this could be enabled on by default on pkgs.stdenv.buildPlatform.isLinux
enableFakechroot ? false
, # We pick 100 to ensure there is plenty of room for extension. I
# believe the actual maximum is 128.
maxLayers ? 100
, # Whether to include store paths in the image. You generally want to leave
# this on, but tooling may disable this to insert the store paths more
# efficiently via other means, such as bind mounting the host store.
includeStorePaths ? true
, # Passthru arguments for the underlying derivation.
passthru ? {}
,
}:
assert
(lib.assertMsg (maxLayers > 1)
"the maxLayers argument of dockerTools.buildLayeredImage function must be greather than 1 (current value: ${toString maxLayers})");
let
baseName = baseNameOf name;
streamScript = writePython3 "stream" { } ./stream_layered_image.py;
baseJson = writeText "${baseName}-base.json" (builtins.toJSON {
inherit config architecture;
os = "linux";
});
contentsList = if builtins.isList contents then contents else [ contents ];
bind-paths = builtins.toString (builtins.map (path: "--bind=${path}:${path}!") [
"/dev/"
"/proc/"
"/sys/"
"${builtins.storeDir}/"
"$out/layer.tar"
]);
# We store the customisation layer as a tarball, to make sure that
# things like permissions set on 'extraCommands' are not overridden
# by Nix. Then we precompute the sha256 for performance.
customisationLayer = symlinkJoin {
name = "${baseName}-customisation-layer";
paths = contentsList;
inherit extraCommands fakeRootCommands;
nativeBuildInputs = [
fakeroot
] ++ optionals enableFakechroot [
proot
];
postBuild = ''
mv $out old_out
(cd old_out; eval "$extraCommands" )
mkdir $out
${if enableFakechroot then ''
proot -r $PWD/old_out ${bind-paths} --pwd=/ --root-id bash -c '
source $stdenv/setup
eval "$fakeRootCommands"
tar \
--sort name \
--exclude=./proc \
--exclude=./sys \
--numeric-owner --mtime "@$SOURCE_DATE_EPOCH" \
--hard-dereference \
-cf $out/layer.tar .
'
'' else ''
fakeroot bash -c '
source $stdenv/setup
cd old_out
eval "$fakeRootCommands"
tar \
--sort name \
--numeric-owner --mtime "@$SOURCE_DATE_EPOCH" \
--hard-dereference \
-cf $out/layer.tar .
'
''}
sha256sum $out/layer.tar \
| cut -f 1 -d ' ' \
> $out/checksum
'';
};
closureRoots = lib.optionals includeStorePaths /* normally true */ (
[ baseJson customisationLayer ]
);
overallClosure = writeText "closure" (lib.concatStringsSep " " closureRoots);
# These derivations are only created as implementation details of docker-tools,
# so they'll be excluded from the created images.
unnecessaryDrvs = [ baseJson overallClosure customisationLayer ];
conf = runCommand "${baseName}-conf.json"
{
inherit fromImage maxLayers created;
imageName = lib.toLower name;
preferLocalBuild = true;
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 ${path} || true)")
unnecessaryDrvs}
}
# Compute the number of layers that are already used by a potential
# 'fromImage' as well as the customization layer. Ensure that there is
# still at least one layer available to store the image contents.
usedLayers=0
# subtract number of base image layers
if [[ -n "$fromImage" ]]; then
(( usedLayers += $(tar -xOf "$fromImage" manifest.json | jq '.[0].Layers | length') ))
fi
# one layer will be taken up by the customisation layer
(( usedLayers += 1 ))
if ! (( $usedLayers < $maxLayers )); then
echo >&2 "Error: usedLayers $usedLayers layers to store 'fromImage' and" \
"'extraCommands', but only maxLayers=$maxLayers were" \
"allowed. At least 1 layer is required to store contents."
exit 1
fi
availableLayers=$(( maxLayers - usedLayers ))
# Create $maxLayers worth of Docker Layers, one layer per store path
# unless there are more paths than $maxLayers. In that case, create
# $maxLayers-1 for the most popular layers, and smush the remainaing
# store paths in to one final layer.
#
# The following code is fiddly w.r.t. ensuring every layer is
# created, and that no paths are missed. If you change the
# following lines, double-check that your code behaves properly
# when the number of layers equals:
# maxLayers-1, maxLayers, and maxLayers+1, 0
paths |
jq -sR '
rtrimstr("\n") | split("\n")
| (.[:$maxLayers-1] | map([.])) + [ .[$maxLayers-1:] ]
| map(select(length > 0))
' \
--argjson maxLayers "$availableLayers" > store_layers.json
# The index on $store_layers is necessary because the --slurpfile
# automatically reads the file as an array.
cat ${baseJson} | jq '
. + {
"store_dir": $store_dir,
"from_image": $from_image,
"store_layers": $store_layers[0],
"customisation_layer", $customisation_layer,
"repo_tag": $repo_tag,
"created": $created
}
' --arg store_dir "${storeDir}" \
--argjson from_image ${if fromImage == null then "null" else "'\"${fromImage}\"'"} \
--slurpfile store_layers store_layers.json \
--arg customisation_layer ${customisationLayer} \
--arg repo_tag "$imageName:$imageTag" \
--arg created "$created" |
tee $out
'';
result = runCommand "stream-${baseName}"
{
inherit (conf) imageName;
preferLocalBuild = true;
passthru = 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
);
# This function streams a docker image that behaves like a nix-shell for a derivation
streamNixShellImage =
{ # The derivation whose environment this docker image should be based on
drv
, # Image Name
name ? drv.name + "-env"
, # Image tag, the Nix's output hash will be used if null
tag ? null
, # User id to run the container as. Defaults to 1000, because many
# binaries don't like to be run as root
uid ? 1000
, # Group id to run the container as, see also uid
gid ? 1000
, # The home directory of the user
homeDirectory ? "/build"
, # The path to the bash binary to use as the shell. See `NIX_BUILD_SHELL` in `man nix-shell`
shell ? bashInteractive + "/bin/bash"
, # Run this command in the environment of the derivation, in an interactive shell. See `--command` in `man nix-shell`
command ? null
, # Same as `command`, but runs the command in a non-interactive shell instead. See `--run` in `man nix-shell`
run ? null
}:
assert lib.assertMsg (! (drv.drvAttrs.__structuredAttrs or false))
"streamNixShellImage: Does not work with the derivation ${drv.name} because it uses __structuredAttrs";
assert lib.assertMsg (command == null || run == null)
"streamNixShellImage: Can't specify both command and run";
let
# A binary that calls the command to build the derivation
builder = writeShellScriptBin "buildDerivation" ''
exec ${lib.escapeShellArg (stringValue drv.drvAttrs.builder)} ${lib.escapeShellArgs (map stringValue drv.drvAttrs.args)}
'';
staticPath = "${dirOf shell}:${lib.makeBinPath [ builder ]}";
# https://github.com/NixOS/nix/blob/2.8.0/src/nix-build/nix-build.cc#L493-L526
rcfile = writeText "nix-shell-rc" ''
unset PATH
dontAddDisableDepTrack=1
# TODO: https://github.com/NixOS/nix/blob/2.8.0/src/nix-build/nix-build.cc#L506
[ -e $stdenv/setup ] && source $stdenv/setup
PATH=${staticPath}:"$PATH"
SHELL=${lib.escapeShellArg shell}
BASH=${lib.escapeShellArg shell}
set +e
[ -n "$PS1" -a -z "$NIX_SHELL_PRESERVE_PROMPT" ] && PS1='\n\[\033[1;32m\][nix-shell:\w]\$\[\033[0m\] '
if [ "$(type -t runHook)" = function ]; then
runHook shellHook
fi
unset NIX_ENFORCE_PURITY
shopt -u nullglob
shopt -s execfail
${optionalString (command != null || run != null) ''
${optionalString (command != null) command}
${optionalString (run != null) run}
exit
''}
'';
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/globals.hh#L464-L465
sandboxBuildDir = "/build";
# This function closely mirrors what this Nix code does:
# https://github.com/NixOS/nix/blob/2.8.0/src/libexpr/primops.cc#L1102
# https://github.com/NixOS/nix/blob/2.8.0/src/libexpr/eval.cc#L1981-L2036
stringValue = value:
# We can't just use `toString` on all derivation attributes because that
# would not put path literals in the closure. So we explicitly copy
# those into the store here
if builtins.typeOf value == "path" then "${value}"
else if builtins.typeOf value == "list" then toString (map stringValue value)
else toString value;
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L992-L1004
drvEnv = lib.mapAttrs' (name: value:
let str = stringValue value;
in if lib.elem name (drv.drvAttrs.passAsFile or [])
then lib.nameValuePair "${name}Path" (writeText "pass-as-text-${name}" str)
else lib.nameValuePair name str
) drv.drvAttrs //
# A mapping from output name to the nix store path where they should end up
# https://github.com/NixOS/nix/blob/2.8.0/src/libexpr/primops.cc#L1253
lib.genAttrs drv.outputs (output: builtins.unsafeDiscardStringContext drv.${output}.outPath);
# Environment variables set in the image
envVars = {
# Root certificates for internet access
SSL_CERT_FILE = "${cacert}/etc/ssl/certs/ca-bundle.crt";
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1027-L1030
# PATH = "/path-not-set";
# Allows calling bash and `buildDerivation` as the Cmd
PATH = staticPath;
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1032-L1038
HOME = homeDirectory;
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1040-L1044
NIX_STORE = storeDir;
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1046-L1047
# TODO: Make configurable?
NIX_BUILD_CORES = "1";
} // drvEnv // {
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1008-L1010
NIX_BUILD_TOP = sandboxBuildDir;
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1012-L1013
TMPDIR = sandboxBuildDir;
TEMPDIR = sandboxBuildDir;
TMP = sandboxBuildDir;
TEMP = sandboxBuildDir;
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1015-L1019
PWD = sandboxBuildDir;
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1071-L1074
# We don't set it here because the output here isn't handled in any special way
# NIX_LOG_FD = "2";
# https://github.com/NixOS/nix/blob/2.8.0/src/libstore/build/local-derivation-goal.cc#L1076-L1077
TERM = "xterm-256color";
};
in streamLayeredImage {
inherit name tag;
contents = [
binSh
usrBinEnv
(fakeNss.override {
# Allows programs to look up the build user's home directory
# https://github.com/NixOS/nix/blob/ffe155abd36366a870482625543f9bf924a58281/src/libstore/build/local-derivation-goal.cc#L906-L910
# Slightly differs however: We use the passed-in homeDirectory instead of sandboxBuildDir.
# We're doing this because it's arguably a bug in Nix that sandboxBuildDir is used here: https://github.com/NixOS/nix/issues/6379
extraPasswdLines = [
"nixbld:x:${toString uid}:${toString gid}:Build user:${homeDirectory}:/noshell"
];
extraGroupLines = [
"nixbld:!:${toString gid}:"
];
})
];
fakeRootCommands = ''
# Effectively a single-user installation of Nix, giving the user full
# control over the Nix store. Needed for building the derivation this
# shell is for, but also in case one wants to use Nix inside the
# image
mkdir -p ./nix/{store,var/nix} ./etc/nix
chown -R ${toString uid}:${toString gid} ./nix ./etc/nix
# Gives the user control over the build directory
mkdir -p .${sandboxBuildDir}
chown -R ${toString uid}:${toString gid} .${sandboxBuildDir}
'';
# Run this image as the given uid/gid
config.User = "${toString uid}:${toString gid}";
config.Cmd =
# https://github.com/NixOS/nix/blob/2.8.0/src/nix-build/nix-build.cc#L185-L186
# https://github.com/NixOS/nix/blob/2.8.0/src/nix-build/nix-build.cc#L534-L536
if run == null
then [ shell "--rcfile" rcfile ]
else [ shell rcfile ];
config.WorkingDir = sandboxBuildDir;
config.Env = lib.mapAttrsToList (name: value: "${name}=${value}") envVars;
};
# Wrapper around streamNixShellImage to build an image from the result
buildNixShellImage = { drv, ... }@args:
let
stream = streamNixShellImage args;
in
runCommand "${drv.name}-env.tar.gz"
{
inherit (stream) imageName;
passthru = { inherit (stream) imageTag; };
nativeBuildInputs = [ pigz ];
} "${stream} | pigz -nTR > $out";
}
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