49 lines
1.5 KiB
Bash
Executable File
49 lines
1.5 KiB
Bash
Executable File
#!/usr/bin/env bash
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# This script takes a single Docker image tag (e.g. "ubuntu:latest") as input
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# and shows the contents of the filesystem for each layer in the image.
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if [ $# -ne 1 ]; then
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echo "Usage: $0 <image_tag>"
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exit 1
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fi
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IMAGE=$1
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# TMPDIR=$(mktemp -d)
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mkdir -p "$PWD/tmp"
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TMPDIR="$PWD/tmp"
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# Save the Docker image to a tar archive
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echo "Saving Docker image '$IMAGE'..."
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if ! docker save "$IMAGE" | pv > "${TMPDIR}/image.tar"; then
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echo "Failed to save image '$IMAGE'. Make sure the image exists and Docker is running."
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rm -rf "${TMPDIR}"
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exit 1
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fi
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cd "${TMPDIR}" || exit 1
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# Extract the top-level metadata of the image tar
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echo "Extracting image metadata..."
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pwd
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tar -xzf image.tar
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chmod -R 777 .
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cd blobs/sha256 || exit 1
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# Typically, the saved image will contain multiple directories each representing a layer.
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# Each layer directory should have a 'layer.tar' file that contains the filesystem for that layer.
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for LAYERFILE in ./*; do
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if [ -f "${LAYERFILE}" ]; then
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mv "${LAYERFILE}" "${LAYERFILE}.tar"
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mkdir -p "${LAYERFILE}"
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tar -xzf "${LAYERFILE}.tar" -C "${LAYERFILE}"
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rm "${LAYERFILE}.tar"
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echo "-----------------------------------------------------------------"
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echo "Contents of layer: ${LAYERFILE%/}"
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echo "-----------------------------------------------------------------"
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# List the files in the layer.tar without extracting
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tree -L 2 "${LAYERFILE}"
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echo
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fi
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done
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