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Docker

This scaffold provides optional Docker support for building and publishing container images. When enabled during initialization, it includes a Dockerfile, an entrypoint script, and GitHub Actions workflows for testing and releasing Docker images.

Dockerfile​

The included Dockerfile uses a minimal Alpine Linux base image with Bash installed. It follows OCI image labeling conventions and uses a dedicated entrypoint script.

FROM alpine:3

RUN apk add --no-cache bash

COPY entrypoint.sh /usr/local/bin/entrypoint.sh

ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]

Entrypoint​

The entrypoint.sh script enforces strict shell options (set -euo pipefail) and forwards arguments to the container command.

Building and running​

# Build the image
docker build -t yournamespace/yourproject .

# Run the container
docker run --rm yournamespace/yourproject

Linting​

The Dockerfile is linted using Hadolint, a Dockerfile linter that helps enforce best practices.

# Lint locally
hadolint Dockerfile

Linting also runs automatically in CI via the test-docker.yml workflow.

CI/CD workflows​

Testing (test-docker.yml)​

Runs on pushes to main and pull requests. This workflow:

  1. Lints the Dockerfile with Hadolint
  2. Builds the Docker image using Docker Buildx
  3. Runs the container to verify it starts correctly

Release (release-docker.yml)​

Runs on tag pushes. This workflow:

  1. Sets up QEMU and Docker Buildx for multi-architecture builds
  2. Authenticates with Docker Hub
  3. Builds and pushes multi-arch images (linux/amd64, linux/arm64)

Docker Hub credentials​

The release workflow requires the following repository secrets:

  • DOCKER_USER — Docker Hub username
  • DOCKER_PASS — Docker Hub access token

Set these in your repository's Settings > Secrets and variables > Actions.