Introducing container-diff, a tool for quickly comparing container images

Container-diff is an open-source tool developed by the Google Container Tools team to help developers identify changes between container images, thereby facilitating the development of containerized software. It addresses the challenge of understanding how changes in a Dockerfile affect the resulting container image, which can lead to bloated images and difficult-to-track issues. By computing semantic differences between images, container-diff provides insights into system and language-level package changes, as well as file modifications, in a readable format. The tool supports image analysis through various formats, including local Docker daemon, remote registry, and tarball files, and can operate independently of a Docker daemon. It proves useful in scenarios such as changelog generation and continuous integration and offers both human-readable and JSON outputs for automated processing. Container-diff also allows for single image analysis to provide detailed information about installed packages and their sizes, aiding in compatibility verification and space management. The team encourages community contributions to expand its capabilities, with potential future support for more languages and runtime environments.