Docker Examples

# 1. Node multi-stage build
FROM node:20-alpine AS deps
WORKDIR /app
COPY package*.json ./
RUN npm ci --omit=dev

FROM node:20-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

FROM gcr.io/distroless/nodejs20-debian12 AS run
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY --from=build /app/dist ./dist
USER nonroot
EXPOSE 3000
CMD ['dist/server.js']

# 2. Go static binary
FROM golang:1.22 AS build
WORKDIR /src
COPY go.* ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 go build -trimpath -ldflags='-s -w' -o /out/app ./cmd/api

FROM scratch
COPY --from=build /out/app /app
EXPOSE 8080
ENTRYPOINT ['/app']

# 3. Python with uv
FROM python:3.12-slim AS build
RUN pip install uv
WORKDIR /app
COPY pyproject.toml uv.lock ./
RUN uv sync --frozen --no-dev
COPY . .

FROM python:3.12-slim
WORKDIR /app
COPY --from=build /app/.venv /app/.venv
COPY --from=build /app /app
ENV PATH='/app/.venv/bin:$PATH'
CMD ['python', '-m', 'myapp']

# 4. HEALTHCHECK
HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
  CMD curl -f http://localhost:3000/healthz || exit 1

# 5. BuildKit cache mount
# syntax=docker/dockerfile:1.7
FROM node:20
WORKDIR /app
COPY package*.json ./
RUN --mount=type=cache,target=/root/.npm npm ci
COPY . .
RUN npm run build

# Common one-liners — see lesson body.
docker run --rm -it python:3-alpine python -c "print('hi')"