build image

Build a Docker image with best practices for caching, security, and size optimization.

Steps

1. Read the existing Dockerfile or generate one if missing.
2. Analyze the build context:
   • Check .dockerignore exists and excludes unnecessary files.
   • Identify the base image and its size.
   • Map build stages and layer count.
3. Build the image with build arguments:
   • docker build -t <name>:<tag> --build-arg VERSION=<ver> .
   • Use BuildKit for improved caching: DOCKER_BUILDKIT=1.
   • Add --platform linux/amd64,linux/arm64 for multi-arch if needed.
4. Verify the build:
   • Check final image size: docker images <name>:<tag>.
   • Run a quick smoke test: docker run --rm <name>:<tag> <health-command>.
   • Scan for vulnerabilities: docker scout cves <name>:<tag>.
5. Tag appropriately:
   • <name>:latest for development.
   • <name>:<version> for releases.
   • <name>:<git-sha-short> for CI builds.
6. Report build results and image details.

Format

Docker Build: <name>:<tag>
Base: <base-image>
Size: <size>MB (layers: )
Build time: <duration>

Vulnerabilities: critical, high, medium
Smoke test: <pass/fail>

Push: docker push <registry>/<name>:<tag>

Rules

• Always use specific base image tags, not latest.
• Include a .dockerignore to minimize build context.
• Run as non-root user in the final image.
• Use multi-stage builds to keep the final image minimal.
• Add health check instruction (HEALTHCHECK) for production images.