67 lines
2.0 KiB
Bash
67 lines
2.0 KiB
Bash
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#!/bin/bash
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set -euo pipefail
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# Parse command line arguments
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while [[ $# -gt 0 ]]; do
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key="$1"
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case "$key" in
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--image)
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IMAGE_NAME="$2"
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shift
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shift
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;;
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*)
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echo "Error: Unknown option: $key"
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echo "Usage: $0 --image IMAGE_NAME"
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exit 1
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;;
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esac
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done
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# Define the path to the temporary directory where the files will be extracted
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DESTINATION="/tmp/docker_images/${IMAGE_NAME}"
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MANIFEST="${DESTINATION}/manifest.json"
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# Define a function to download and extract the Docker image layers
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function extract_docker_image {
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# Pull image to make sure we have it before we save it.
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docker pull "$IMAGE_NAME"
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# Save the Docker image as a tar file
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echo "Saving Docker image as a tar file..." >&2
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docker save "$1" -o "${DESTINATION}/${IMAGE_NAME}.tar"
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# Extract the Docker image layers to the destination directory
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echo "Extracting Docker image layers..." >&2
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mkdir -p "${DESTINATION}/layers"
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tar -xf "${DESTINATION}/${IMAGE_NAME}.tar" -C "${DESTINATION}/"
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# Rename the layer directories to their respective layer IDs
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LAYERS=$(jq -r '.[0].Layers[]' "${MANIFEST}")
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# Extract each layer
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for LAYER in ${LAYERS}; do
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BLOB="${LAYER}"
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# Extract the layer tar file to the destination directory
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echo "Extracting layer ${LAYER}..." >&2
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mkdir -p "${DESTINATION}/$(dirname ${BLOB})"
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tar -xf "${DESTINATION}/${BLOB}" -C "${DESTINATION}/layers"
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echo "Layer ${LAYER} extracted" >&2
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done
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}
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# Ensure that the user has provided the Docker image name using the --image flag
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if [ -z "$IMAGE_NAME" ]; then
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echo "Error: Docker image name not provided." >&2
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echo "Usage: $0 --image IMAGE_NAME" >&2
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exit 1
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fi
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# Create the destination directory if it doesn't already exist
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rm -rf "${DESTINATION}"
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mkdir -p "${DESTINATION}"
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# Call the function to download and extract the Docker image layers
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extract_docker_image "$IMAGE_NAME"
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