image-build/README.md

action/image-build

Composite Gitea Action that builds a container image with buildx and optionally runs a smoke test. Does not push — pair with action/image-push to publish.

Splitting build from push lets a PR workflow run image-build (no secrets, no side effects) for validation while main runs the full build → push → deploy chain.

Usage

- uses: actions/checkout@v4
- uses: https://code.fritzlab.net/action/image-build@v1
  with:
    image: code.fritzlab.net/fritzlab/chrony
    smoke-test: docker run --rm --entrypoint /usr/sbin/chronyd $IMAGE -v

The image is built and tagged as <image>:<github.run_number> in the runner's local Docker daemon. Subsequent steps (e.g. action/image-push) can reference the same tag.

Inputs

Name	Required	Default	Description
image	yes	—	Full image name without tag (e.g. code.fritzlab.net/fritzlab/chrony).
context	no	.	Docker build context.
build-args	no	—	Multiline KEY=VALUE build args.
smoke-test	no	—	Shell command run after build. $IMAGE is set to <image>:<run_number>. Non-zero exit fails the action.

Outputs

Name	Description
tag	Numeric tag assigned (= github.run_number).

Smoke test patterns

Override entrypoint for a binary that expects no args:

smoke-test: docker run --rm --entrypoint /usr/sbin/chronyd $IMAGE -v

Run a help command that returns non-zero:

smoke-test: docker run --rm $IMAGE --help || true

Multiple checks chained:

smoke-test: |
  docker run --rm $IMAGE --version
  docker run --rm --entrypoint /bin/sh $IMAGE -c 'test -x /usr/local/bin/myapp'