docker-image-template

Template repo for clbsoldev Docker images: build → content digest comparison → publish to GHCR (optionally Docker Hub), multi-arch (linux/amd64,linux/arm64).

Creating a new image from this template

1. "Use this template" → create a new repo. Repo name = resulting image name (e.g. repo syslog-logdy-server → ghcr.io/clbsoldev/syslog-logdy-server). The workflow derives the image name from the repo name automatically — .github/workflows/build.yml does not need to be changed for this.
2. Replace the entire image/ directory with your actual image.
3. Pin the base image by digest:

   docker buildx imagetools inspect <image>:<tag>

   Enter the top-level digest (manifest list, not docker inspect — that one only reflects the local host's architecture and would break arm64 builds) into the Dockerfile.
4. Replace Readme.md and Changelog.md with project-specific content.
5. If Docker Hub should be used: set the repo variable ENABLE_DOCKERHUB=true, add DOCKERHUB_USERNAME/DOCKERHUB_TOKEN as secrets, and add a short-description to the dockerhub-description step in build.yml (that's project-specific text and can't be derived generically).

How build.yml behaves

• Image name: derived automatically from the repo name, with a leading docker- prefix stripped if present (matches the docker-<name> repo naming convention, e.g. repo docker-syslog-logdy-server → image ghcr.io/clbsoldev/syslog-logdy-server). No workflow edit needed per repo.
• Publish gate: the check job hashes the built OCI tarball and compares it against digest.txt from the last run. Only if the content actually changed does publish run — so a weekly cron rebuild with no real change (e.g. base image unchanged) doesn't spam a new :latest push.
• Docker Hub is off by default. To enable it on a given repo: set the repo variable ENABLE_DOCKERHUB=true (Settings → Secrets and variables → Actions → Variables), and add DOCKERHUB_USERNAME / DOCKERHUB_TOKEN as secrets. Without the variable, both Docker Hub steps are skipped entirely — GHCR publishing always happens regardless of this toggle.

Labels

.github/labels.yml is automatically synced to the repo on every push that changes this file (label-sync.yml, via micnncim/action-label-syncer). Just add/change labels there and push.

Known limitation of "Use this template"

GitHub does not copy repository labels when using "Use this template" — only files. That's what the separate label-sync.yml workflow is for: it runs automatically on the first push to main in the new repo and creates the labels from labels.yml, with no manual step required.