docker-helper_skill

Overview

This skill is a Docker and container orchestration expert focused on development and deployment workflows. It provides practical guidance on Dockerfile creation, image optimization, Compose patterns, security, and troubleshooting. The advice targets reproducible builds, smaller images, and safer runtime configurations.

How this skill works

The skill inspects Dockerfile structure, build stages, and layering to recommend optimizations like combined RUN commands, multi-stage builds, and appropriate base images. It evaluates Compose setups for dev vs production, suggests secrets management, health checks, resource limits, and common debugging commands. It also offers scanning and cleanup commands to maintain secure, lean images.

When to use it

• Creating or refactoring Dockerfiles for development or production
• Optimizing image size, build time, and layer cache usage
• Designing Docker Compose for local development or production deployments
• Troubleshooting container failures, logs, or resource issues
• Implementing security best practices and secret management

Best practices

• Use specific version tags or minimal bases (alpine, distroless) instead of latest
• Combine RUN commands and clean package caches to reduce layers and size
• Adopt multi-stage builds to separate build artifacts from runtime images
• Run containers as a non-root user and avoid including secrets in environment variables
• Define healthchecks, resource limits, and restart policies for production services
• Add a .dockerignore and copy dependency files before source to improve cache usage

Example use cases

• Create a multi-stage Rust build that produces a small runtime binary in a slim base image
• Convert a development Compose file with volume mounts and hot reload into a production Compose with fixed images and replicas
• Debug a failing container by attaching a shell, inspecting logs, and checking inspect output
• Scan images with Trivy or Docker Scout and remediate vulnerable packages
• Implement Docker secrets for credentials and move secret injection out of env vars