LoopyLuci Dockerfile Optimization
Optimizing Docker builds for speed, size, and security.
Multi-stage Build
FROM golang:1.21 AS builder
WORKDIR /app; COPY go.mod .; RUN go mod download
COPY . .; RUN CGO_ENABLED=0 go build -o server
FROM alpine:3.18
COPY --from=builder /app/server /server
CMD ["/server"]
Layer Caching
FROM node:20-alpine
COPY package*.json ./
RUN npm ci --only=production
COPY . .
RUN npm run build
Combine RUN
RUN apt-get update && apt-get install -y curl \\
&& rm -rf /var/lib/apt/lists/*
BuildKit
$env:DOCKER_BUILDKIT=1
docker build --no-cache --progress=plain -t myapp .
Pitfalls
- COPY . before deps invalidates caches
- apt install without cleanup bloats image
- Distroless has no shell -- use docker debug