Imported from pjt222/agent-almanac (i18n/wenyan-ultra/skills/create-multistage-dockerfile/SKILL.md). Install upstream with npx skills add pjt222/agent-almanac --skill create-multistage-dockerfile. Copyright stays with the author (MIT).

造多段 Dockerfile

構多段 Dockerfile 分構與行境以生最小產像。

用

• 產像過大（>500MB 為編譯語）
• 構具（編、發頭）入終像
• 自一 Dockerfile 生發與產異像
• 部於限境（邊、無服）

入

• 必：存 Dockerfile 或待容器化案
• 必：語與構系（npm、pip、go build、cargo、maven）
• 可：目行基（slim、alpine、distroless、scratch）
• 可：終像寸預

行

一：別構與行依

二：構多段構

核模：構於肥像、複品至瘦像。

# ---- Build Stage ----
FROM <build-image> AS builder
WORKDIR /src
COPY <dependency-manifest> .
RUN <install-dependencies>
COPY . .
RUN <build-command>

# ---- Runtime Stage ----
FROM <runtime-image>
COPY --from=builder /src/<artifact> /<dest>
EXPOSE <port>
CMD [<entrypoint>]

三：施語專模

Node.js（剪 node_modules）

FROM node:22-bookworm AS builder
WORKDIR /src
COPY package.json package-lock.json ./
RUN npm ci
COPY . .
RUN npm run build && npm prune --omit=dev

FROM node:22-bookworm-slim
RUN groupadd -r app && useradd -r -g app app
WORKDIR /app
COPY --from=builder /src/dist ./dist
COPY --from=builder /src/node_modules ./node_modules
COPY --from=builder /src/package.json .
USER app
EXPOSE 3000
CMD ["node", "dist/index.js"]

Python（虛境複）

FROM python:3.12-bookworm AS builder
WORKDIR /src
RUN python -m venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .

FROM python:3.12-slim-bookworm
COPY --from=builder /opt/venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"
WORKDIR /app
COPY --from=builder /src .
RUN groupadd -r app && useradd -r -g app app
USER app
EXPOSE 8000
CMD ["python", "app.py"]

Go（靜二入 scratch）

FROM golang:1.23-bookworm AS builder
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /server ./cmd/server

FROM scratch
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
COPY --from=builder /server /server
EXPOSE 8080
ENTRYPOINT ["/server"]

Rust（靜 musl 二）

FROM rust:1.82-bookworm AS builder
RUN apt-get update && apt-get install -y musl-tools && rm -rf /var/lib/apt/lists/*
RUN rustup target add x86_64-unknown-linux-musl
WORKDIR /src
COPY Cargo.toml Cargo.lock ./
RUN mkdir src && echo "fn main() {}" > src/main.rs \
    && cargo build --release --target x86_64-unknown-linux-musl \
    && rm -rf src
COPY . .
RUN touch src/main.rs && cargo build --release --target x86_64-unknown-linux-musl

FROM scratch
COPY --from=builder /src/target/x86_64-unknown-linux-musl/release/myapp /myapp
EXPOSE 8080
ENTRYPOINT ["/myapp"]

得： 終像僅含行與編品。

敗： 察 COPY --from=builder 路。用 docker build --target builder 除構段。

四：擇行基

注： Alpine 用 musl libc。某 Python wheels 與 Node native modules 或不行。解譯語宜用 -slim（glibc）。

五：跨段構引

ARG APP_VERSION=0.0.0

FROM golang:1.23 AS builder
ARG APP_VERSION
RUN go build -ldflags="-X main.version=${APP_VERSION}" -o /server .

FROM gcr.io/distroless/static
COPY --from=builder /server /server
ENTRYPOINT ["/server"]

構以：docker build --build-arg APP_VERSION=1.2.3 .

注： FROM 前之 ARG 為全。各段須重申 ARG 以用之。

六：較像寸

# Build both variants
docker build -t myapp:fat --target builder .
docker build -t myapp:slim .

# Compare sizes
docker images --format "table {{.Repository}}\t{{.Tag}}\t{{.Size}}" | grep myapp

得： 產像較構段小 50-90%。

驗

• docker build 諸段畢
• 終像不含構具（編、發頭）
• docker run 於瘦像正行
• 像寸較單段顯減
• COPY --from=builder 路正
• 無源漏入產像

忌

• 缺行庫：編碼或需共庫（libc、libssl）。瘦像須全試
• 破 COPY --from 路：品路須合。用 docker build --target builder 再 docker run --rm builder ls /path 除
• Alpine musl 問：Native Node.js addons 與某 Python 包於 Alpine 敗。用 -slim
• 全 ARG 範：FROM 前申之 ARG 僅於 FROM 行可。各段用則重申
• 忘 CA 證：scratch 無證。自 builder 複 /etc/ssl/certs/ca-certificates.crt 或用 distroless

參

• create-dockerfile - 單段標 Dockerfile
• create-r-dockerfile - R 專 Dockerfile 用 rocker 像
• optimize-docker-build-cache - 層快與 BuildKit 特
• setup-compose-stack - 用多段像之 compose 設