When authoring a Docker container action, which action.yml configuration correctly points at a Dockerfile in the action repository?
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Short Explanation and Infographic
Container actions use runs.using: docker and runs.image set to Dockerfile or an image reference. Composite and node20 are other action types; services are job sidecars, not action packaging.
Full explanation below image
Full Explanation
Docker container actions package logic in a container image built from a Dockerfile in the action repo or pulled from a registry. In action.yml, set runs.using to docker and runs.image to Dockerfile (relative path) or to an image URI. You can pass args and env as documented for container actions. Composite actions use using: composite and steps; JavaScript actions use node20 (etc.). Job-level services: containers support databases during a workflow job but are not how you publish a reusable Marketplace/container action. Pin action versions for consumers, keep images minimal, and avoid baking secrets into layers.