node.js - Docker 构建在第一阶段之前运行第二阶段

Question

我正在关注 documentation编写多阶段构建。
我的 Dockerfile:

FROM ubuntu:trusty
RUN apt-get update && apt-get install apt-transport-https -y
RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
RUN sh -c 'echo "deb [arch=amd64] https://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list'
RUN apt-get update && apt-get install google-chrome-stable -y

FROM node:alpine
COPY . ./
RUN npm install
RUN npm run lighthouse

我正在尝试在运行 Google Lighthouse 之前将 Google Chrome 安装到图像上。但是，根据日志，构建首先运行第二阶段。

 => CACHED [stage-1 2/4] COPY . ./                                                                                   0.0s 
 => [stage-1 3/4] RUN npm install                                                                                  100.8s
 => ERROR [stage-1 4/4] RUN npm run lighthouse   

为什么会这样？

Answer 1

它们是并行运行的，因为两个阶段都不依赖于彼此。如果您这样做只是为了了解 docker 中的多阶段构建；这是一个示例:

FROM ubuntu:trusty
RUN apt-get update && apt-get install apt-transport-https -y
RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
RUN sh -c 'echo "deb [arch=amd64] https://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list'
RUN apt-get update && apt-get install google-chrome-stable -y

FROM someangularapp:alpine as builder
COPY . ./
RUN npm install
RUN ng build 

##Above stage generates a `dist` folder in its workspace

FROM nginx:latest as deployer
COPY --from=builder /app/dist /usr/share/nginx/html/

现在无论何时运行: docker build -t someimagename --target deployer .builder 阶段在 deployer 阶段之前执行...因为 deployer 使用 --from=builder这意味着在这种情况下，它依赖于构建器阶段来复制一些文件。