Perf improvement

[dben]

This pull request updates the Docker build and push GitHub Action to improve cache handling, resource cleanup, and notification messaging. The main changes focus on optimizing build cache usage, cleaning up after scans, and clarifying Slack notifications in case of failures.

Build cache management and optimization:

• Introduced a scoped cache for Docker Buildx using a hash of the image name, ensuring cache isolation per image and improving cache efficiency during both local scan builds and registry pushes. [1] [2] [3]
• The local scan build step now only imports a scoped cache without exporting another cache copy, while the registry push step exports a minimal scoped cache and ignores errors if cache export is unavailable. [1] [2]

Resource cleanup and disk usage:

• Added steps to report disk usage before scanning, reclaim BuildKit cache before the scan, and remove local scan images and temporary files after scanning to free up disk space and avoid resource leaks. [1] [2] [3]

Slack notification improvements:

• Updated Slack notification messages to clarify that failures can occur during the Docker build, scan, or push steps, not just during the CVE check, and improved the details in the notification blocks. [1] [2] [3]

Other workflow improvements:

• Added a dedicated cleanup step in the workflow summary and reordered steps in the documentation to reflect the new workflow sequence.

These changes make the workflow more robust, efficient, and easier to debug when failures occur.

[github-actions]

🔍 Vulnerabilities of ghcr.io/enosix/ghac-docker-github/testing:testing

📦 Image Reference ghcr.io/enosix/ghac-docker-github/testing:testing

digest	sha256:136f06bd426d6d342e25b20bbfaa45e295070170f560d177a6e732fcc0a5d8f6
vulnerabilities
platform	linux/amd64
size	16 MB
packages	26

📦 Base Image alpine:3.23

also known as	3.23.5
digest	sha256:1beb0dc0a51de7ff38e3b5274078a2e0b81113ba5c7535e1a03d5913a5edbda3
vulnerabilities