Refactor to use functions, fixes #2; set up subcommand dispatch, fixes #3

This commit is contained in:
Joe 2021-04-30 21:27:37 -05:00
parent f818ecc2bc
commit 044f63a10a
2 changed files with 132 additions and 50 deletions

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@ -2,62 +2,143 @@
set -e
verbose=1
image="$1"
export searchpath="$2"
export tarfile="$(mktemp)-$image.tar"
# check to see if image exists locally
if ! docker image inspect "$image" > /dev/null ; then
exit 1
fi
# Save image tar to temp file
[ $verbose ] && >&2 echo "Exporting image '$image' to temp file '$tarfile'..."
docker image save "$image" -o "$tarfile"
# Set up cleanup to not leave image behind
function onexit() {
[ $verbose ] && >&2 echo "Cleaning up exported image '$tarfile'"
rm "$tarfile"
function docker_cli_plugin_metadata {
local vendor="infogulch"
local version="v0.0.1"
local description="Manage Artifacts in Docker Images"
local url="https://github.com/infogulch/docker-artifact"
printf '{"SchemaVersion":"0.1.0","Vendor":"%s","Version":"%s","ShortDescription":"%s","URL":"%s"}\n' \
"$vendor" "$version" "$description" "$url"
}
trap onexit EXIT
# Extract manifest and config file contents
[ $verbose ] && >&2 echo "Collecting metadata from image..."
manifest=$(tar -xf "$tarfile" -x manifest.json -O | jq)
config_file=$(echo "$manifest" | jq -r '.[0].Config')
config=$(tar -f "$tarfile" -x "$config_file" -O | jq)
__usage="
Usage: docker artifact [command] [options]
# Combine manifest.json and config json to build a map from tar layer directory to layer id sha
export idmap=$(echo "$manifest" "$config" | jq -sr '[ [ .[0][0].Layers, .[1].rootfs.diff_ids ] | transpose[] | { (.[0]): .[1] } ] | reduce .[] as $x ({}; . * $x)')
Commands:
# Search each layer for a file matching $searchpath
# TODO also search for related whiteout files that start with `.wh.`
[ $verbose ] && >&2 echo "Searching layers for '$searchpath'..."
found=$(echo "$manifest" | jq '.[0].Layers[]' | xargs -I {} sh -c 'digest=$(echo "$idmap" | jq -r ".[\"{}\"]"); tar -f "$tarfile" -x {} -O | tar -t | sed s_^_/_ | grep -wx "$searchpath" | xargs -I [] echo "[]=$digest"')
ls - List files available to download directly from an image
download - Download files directly from an image that has been labeled
label - Label an image
foundcount=$(echo "$found" | grep -c . || true)
Command usage:
# If more than one is found, then bail
if [ $foundcount -gt 1 ]; then
>&2 echo "File was changed in multiple layers, aborting. Found files and layer ids:"
>&2 echo "$found"
exit 2
elif [ $foundcount -eq 0 ]; then
>&2 echo "No files found matching '$searchpath'"
exit 3
fi
docker artifact ls [options] image_name
docker artifact download [options] image_name file...
docker artifact label [options] image_name file...
labels=$(echo "$found" | sed 's_^.*$_--label "\0"_' | paste -d' ')
Options:
-v - verbose output
-q - quiet output
# Add a layer to the existing image to add the labels and tag the new image with the same image name
[ $verbose ] && >&2 echo "Rebuilding image and adding labels: $labels"
echo "FROM $image" | eval docker build $labels -t "$image" - &> /dev/null
Examples:
echo "Rebuilt image '$image' with the following added labels:"
docker image inspect "$image" | jq '.[0].Config.Labels'
echo "Run 'docker push $image' to push it to docker hub"
docker artifact ls infogulch/artifact-test
docker artifact download infogulch/artifact-test /app/othertestfile.txt
docker artifact label infogulch/artifact-test /testfile.txt
"
exit
function main {
case "$1" in
docker-cli-plugin-metadata)
docker_cli_plugin_metadata
;;
artifact)
case "$2" in
ls)
list "${@:3}"
;;
label)
label "${@:3}"
;;
download)
download "${@:3}"
;;
*)
echo "$__usage"
;;
esac
;;
esac
}
function _search_layer {
local idmap="$1"
local imagetar="$2"
local layertar="$3"
local search="$4"
# look up digest associated with layer path
local digest="$(jq --arg key "$layertar" -r '.[$key]' <<< "$idmap")"
# extract layer from image | list files in layer | add / prefix | search for file | append =$digest to each found file
tar -f "$imagetar" -x "$layertar" -O | tar -t | sed s_^_/_ | grep -wx "$search" | sed 's_.$_\0='"$digest"'_'
}
function label {
local image="$1"
local searchpath="$2"
local tarfile="$(mktemp).tar"
# check to see if image exists locally. If not, Docker already prints an error so just exit
if ! docker image inspect "$image" > /dev/null ; then
exit 1
fi
# Save image tar to temp file
LOG "Exporting image '$image' to temp file '$tarfile'..."
docker image save "$image" -o "$tarfile"
# Set up cleanup to not leave image behind
trap "delete_files '$tarfile'; trap - RETURN" RETURN
# Extract manifest and config file contents
LOG "Collecting metadata from image..."
local manifest="$(tar -xf "$tarfile" -x manifest.json -O | jq)"
local config_file="$(echo "$manifest" | jq -r '.[0].Config')"
local config="$(tar -f "$tarfile" -x "$config_file" -O | jq)"
# Combine manifest.json and config json to build a map from tar layer directory to layer id sha
local idmap="$(echo "$manifest" "$config" | jq -s '[ [ .[0][0].Layers, .[1].rootfs.diff_ids ] | transpose[] | { (.[0]): .[1] } ] | reduce .[] as $x ({}; . * $x)')"
# Search each layer for a file matching $searchpath
# TODO also search for related whiteout files that start with `.wh.`
LOG "Searching layers for '$searchpath'..."
local found="$(echo "$manifest" | jq -r '.[0].Layers[]' | xargs -L1 -I {} bash -c '_search_layer "$@"' _ "$idmap" "$tarfile" {} "$searchpath")"
local foundcount="$(echo "$found" | grep -c . || true)"
# If more than one is found, then bail
if [ $foundcount -gt 1 ]; then
echo "File was changed in multiple layers, aborting. Found files and layer ids:"
echo "$found"
exit 2
elif [ $foundcount -eq 0 ]; then
echo "No files found matching '$searchpath'"
exit 3
fi
local labels="$(echo "$found" | sed 's_^.*$_--label "\0"_' | paste -d' ')"
# Add a layer to the existing image to add the labels and tag the new image with the same image name
LOG "Rebuilding image and adding labels: $labels"
echo "FROM $image" | eval docker build $labels -t "$image" - &> /dev/null
LOG "All image labels:"$'\n'"$(docker image inspect "$image" | jq '.[0].Config.Labels' | sed 's_^_ _' )"
# Remind user to push image
echo " [*] Rebuilt image '$image' to add $foundcount labels"
echo " [*] Run 'docker push $image' to push it to your container repository"
}
function delete_files {
LOG "Cleaning up temp files $@"
rm "$@"
}
export verbose=1
function LOG {
[ $verbose ] && >&2 echo -e "$(tput setaf 4) ==> $@$(tput sgr0)"
}
# Export functions used in subshells
export -f LOG
export -f _search_layer
main "$@"

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@ -5,11 +5,12 @@ source=$(dirname "${BASH_SOURCE[0]}")
pushd "$source" &> /dev/null
# Build example image
docker build . -t test-image &> /dev/null
echo "Rebuilding docker image for example"
docker build . -t infogulch/test-image &> /dev/null
# Execute docker artifact to add a label to /app/othertestfile.txt
set +e
../docker-artifact.sh test-image /app/othertestfile.txt
../docker-artifact.sh artifact label infogulch/test-image /app/othertestfile.txt
popd &> /dev/null