The docker-image-extract script pulls and extracts all files from an image in Docker Hub. For multi-platform images, you can choose the platform-specific image to pull.

docker-image-extract has minimal dependencies that should exist in pretty much any Linux environment, with the possible exception of curl/wget:

• curl or wget
• find
• grep
• gzip
• mkdir
• rm
• sed
• sh
• tar

If you are using BusyBox, version 1.34.0 or later is required, as the wget implementation in earlier versions does not recognize the HTTP 307/308 redirects returned by Docker Hub.

Usage

./docker-image-extract [OPTIONS...] IMAGE[:REF]

IMAGE can be a community user image (like 'some-user/some-image') or a
Docker official image (like 'hello-world', which contains no '/').

REF is either a tag name or a full SHA-256 image digest (with a 'sha256:' prefix).
The default ref is the 'latest' tag.

Options:

  -p PLATFORM  Pull image for the specified platform (default: linux/amd64)
               For a given image on Docker Hub, the 'Tags' tab lists the
               platforms supported for that image.
  -o OUT_DIR   Extract image to the specified output dir (default: ./output)
  -h           Show help with usage examples

Examples:

# Pull and extract all files in the 'hello-world' image tagged 'latest'.
$ ./docker-image-extract hello-world:latest

# Same as above; ref defaults to the 'latest' tag.
$ ./docker-image-extract hello-world

# Pull the 'hello-world' image for the 'linux/arm64/v8' platform.
$ ./docker-image-extract -p linux/arm64/v8 hello-world

# Pull an image by digest.
$ ./docker-image-extract hello-world:sha256:90659bf80b44ce6be8234e6ff90a1ac34acbeb826903b02cfa0da11c82cbc042

Sample output

$ ./docker-image-extract busybox:musl
Getting API token...
Getting image manifest for library/busybox:musl...
Fetching and extracting layer e4df39e4f349fc83694349a5a94afc8d9857fa66f7421427f3d2463a58d876d3...
Image contents extracted into ./output.
$ ls output
bin  dev  etc  home  root  tmp  usr  var
$ ls -l output/bin/{busybox,ls}
-rwx------ 393 jjlin users 1148648 Apr  7 13:18 output/bin/busybox
-rwx------ 393 jjlin users 1148648 Apr  7 13:18 output/bin/ls

See also

• https://rmannibucau.metawerx.net/post/docker-extracts-fileystem-with-bash

  The logic in this script is based on this blog post, but pretty much everything has been rewritten and improved.

• https://github.com/moby/moby/blob/master/contrib/download-frozen-image-v2.sh

  This script downloads the layers of a Docker image in a form suitable for use with docker load. It doesn't actually extract the layers, though.