docker-image-diff 0.1.0

Generate and apply diffs between Docker image tar archives

docker-image-diff

A tool to generate and apply diffs between Docker image tar archives, allowing you to package only the updated parts for offline updates.

Features

• Diff: Create a diff tar containing only files added or changed between two Docker image tar files.
• Merge: Merge a diff tar back into a base tar to reconstruct the updated image.
• Prints size summary for base, new, and diff archives.

Requirements

• Python 3.10 or above
• Standard library only (no external dependencies)

Installation

If published on PyPI, install with:

pip install docker-image-diff

Or to use from source:

git clone <repo-url>
cd docker-image-diff
pip install .

Usage

# Generate a diff archive:
dockerdiff diff --base <base tar path> --new <new tar path> --output <diff tar path>

# Merge a diff archive into the base to create the updated image:
dockerdiff merge --base <base tar path> --diff <diff tar path> --output <new tar path>

Examples

# Create a diff between two images:
$ dockerdiff diff --base ubuntu_old.tar --new ubuntu_new.tar --output ubuntu_diff.tar

# Reconstruct the updated image on an offline server:
$ dockerdiff merge --base ubuntu_old.tar --diff ubuntu_diff.tar --output ubuntu_reconstructed.tar

Output

After running a command, the tool prints a summary of the archive sizes:

Base image size: 123.45 MB
New image size: 130.67 MB
Diff image size: 7.22 MB

Use these numbers to verify that only the changed content was packaged.

Author

Junghyun Kwon

Version

0.1.0

License

This project is licensed under the Apache License 2.0.