Write or review a Dockerfile and compose setup for a production service: multi-stage builds that ship only the runtime, pinned base images, layer order for cache hits, non-root user, minimal image size, correct signal handling and health checks, secrets kept out of layers, and language-specific patterns for Node, Python, Go, and Java. Use when containerising a service, when images are large or slow to build, when a container ignores SIGTERM, or when a security scan flags the image.
