Docker Layer Optimization

Optimize Docker builds for speed through proper layer ordering, BuildKit caching, and CI/CD integration.

Core Principles

1. Layer order matters - least-changing content first, most-changing last
2. Separate dependencies from code - package manifests before source
3. Use BuildKit cache mounts - persist package manager caches between builds
4. Multi-stage builds - separate build-time from runtime dependencies

Layer Ordering Pattern

# 1. Base image (rarely changes)
FROM node:20-slim AS base