Docker构建报错：yarn build命令未找到，请求技术支持

我编写了如下Dockerfile：

FROM node:lts-alpine

WORKDIR /app

COPY package.json ./
COPY yarn.lock ./

COPY client/package.json client/
COPY client/yarn.lock client/
RUN yarn install

COPY server/package.json server/
COPY server/yarn.lock server/
RUN yarn install

COPY client/ client/
RUN yarn build <--- 此处报错
COPY server/ server/

USER node
CMD ["yarn", "start"]
EXPOSE 8000

我的项目包含3个package.json文件，分别位于app根目录、client目录和server目录中，build命令定义在client/package.json中（如下所示）：

{
  "name": "myApp",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.14.1",
    "@testing-library/react": "^13.0.0",
    "@testing-library/user-event": "^13.2.1",
    "axios": "^1.3.6",
    "ethers": "5.4.7",
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "react-scripts": "5.0.1",
    "web-vitals": "^2.1.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "BUILD_PATH=../server/public react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}

执行docker build -t myApp .时，持续收到报错：error Command "build" not found。参考过类似教程，根目录未添加build脚本也能正常运行，刚接触Docker，需要帮助完成项目编译。

报错原因很明确：当前工作目录是/app，直接运行yarn build会读取根目录package.json中的脚本，但你的build命令定义在client/package.json里，因此找不到对应命令。

有两种可行的解决方式：

1. 切换到client目录执行build命令
   修改Dockerfile中的报错行，切换到client目录后再执行build：

   RUN cd client && yarn build
   

   如果你的根目录package.json配置了workspaces（这可能是教程能正常运行的原因），也可以直接通过workspace指定执行client的build脚本：

   RUN yarn workspace client build
   

   若使用workspace方式，需要在根目录package.json中添加如下配置：

   {
     "workspaces": ["client", "server"]
   }
   

2. 多阶段构建优化镜像（推荐）
   为了缩小最终镜像体积、提升构建效率，可以采用多阶段构建：先完成client的编译，再将产物复制到server环境中，只保留运行必需的依赖：

   # 第一阶段：构建client静态文件
   FROM node:lts-alpine as builder
   WORKDIR /app
   COPY client/package.json client/yarn.lock ./client/
   RUN cd client && yarn install --frozen-lockfile
   COPY client/ ./client/
   RUN cd client && yarn build
   
   # 第二阶段：部署server
   FROM node:lts-alpine
   WORKDIR /app
   COPY server/package.json server/yarn.lock ./server/
   RUN cd server && yarn install --frozen-lockfile --production
   # 从构建阶段复制编译好的静态文件到server的public目录
   COPY --from=builder /app/server/public ./server/public
   COPY server/ ./server/
   
   USER node
   CMD ["yarn", "--cwd", "server", "start"]
   EXPOSE 8000
   

内容的提问来源于stack exchange，提问作者src2012