# Before: 1.2GB
FROM node:20

# After: 150MB (88% smaller)
FROM node:20-alpine

# Bad: 3 layers, 150MB
RUN apt-get update
RUN apt-get install -y curl
RUN rm -rf /var/lib/apt/lists/*

# Good: 1 layer, 50MB
RUN apt-get update && \
    apt-get install -y --no-install-recommends curl && \
    rm -rf /var/lib/apt/lists/*

# Clean package manager cache
RUN npm cache clean --force
RUN pip cache purge
RUN apt-get clean && rm -rf /var/lib/apt/lists/*

# Use .dockerignore
# node_modules, .git, *.md, tests/, docs/

# Dependencies first (rarely change)
COPY package*.json ./
RUN npm ci

# Source code last (frequently changes)
COPY . .
RUN npm run build

# syntax=docker/dockerfile:1
FROM node:20-alpine

# Cache npm packages
RUN --mount=type=cache,target=/root/.npm \
    npm ci

# Cache pip packages
RUN --mount=type=cache,target=/root/.cache/pip \
    pip install -r requirements.txt

# Parallel stages (BuildKit)
FROM node:20-alpine AS deps
COPY package*.json ./
RUN npm ci

FROM deps AS builder
COPY . .
RUN npm run build

FROM deps AS linter
COPY . .
RUN npm run lint

services:
  app:
    deploy:
      resources:
        limits:
          cpus: '1'
          memory: 512M
        reservations:
          cpus: '0.5'
          memory: 256M

# Set memory limits
docker run --memory=512m --memory-swap=512m app

# CPU limits
docker run --cpus=1.5 app

# I/O limits
docker run --device-read-bps=/dev/sda:1mb app

# Image size analysis
docker images --format "table {{.Repository}}\t{{.Tag}}\t{{.Size}}"

# Layer analysis
docker history <image> --format "{{.Size}}\t{{.CreatedBy}}"

# Deep dive analysis
dive <image>

# Build time analysis
DOCKER_BUILDKIT=1 docker build --progress=plain .

Skill("docker-optimization")