我的项目具有这样的monorepo结构：

babel.config.js
  a-something
  b-something

在项目的根目录中有babel配置文件，还有软件包a-something和b-something。 在软件包a-something中，我具有以下webpack配置：

const path = require('path')

module.exports = {
  target: 'node',entry: './src/index.js',output: {
    filename: 'bundle.js',path: path.resolve(__dirname,'build')
  },devtool: 'source-map',module: {
    rules: [
      {
        test: /\.js?$/,use: {
          loader: 'babel-loader',options: {
            rootMode: 'upward'
          }
        },include: [
          path.resolve(__dirname,'src'),/node_modules\/a-/,/node_modules\/b-/
        ]
      }
    ]
  }
}

在包a-something中，我有以下package.json：

{
  "name": "a-something","version": "1.0.0","description": "","main": "index.js","scripts": {
    "prod:build": "webpack --config webpack.config.js","prod:start": "node build/bundle.js"
  },"author": "","license": "ISC","dependencies": {
    "express": "^4.16.2","graphql": "^14.5.8","graphql-request": "^1.8.2","graphql-tag": "^2.10.1","b-something": "^1.0.0","node-fetch": "^2.6.0","sitemap": "^5.0.0"
  },"devDependencies": {
    "webpack": "3.5.6","@babel/polyfill": "7.7.0"
  }
}

我的根package.json具有以下依赖关系：

"@babel/cli": "^7.5.5","@babel/core": "^7.5.5","babel-loader": "8.0.6"

最后，我在软件包a-something中的Dockerfile是：

FROM node:10.15.1
COPY ./package.json /src/package.json
ENV PORT 3000
ENV NODE_ENV production
WORKDIR /src
RUN npm install
COPY ./lerna.json /src/lerna.json
COPY ./packages/a-something/package.json /src/packages/a-something/package.json
COPY ./packages/b-something/package.json /src/packages/b-something/package.json
RUN npm run clean
COPY . /src
WORKDIR /src/packages/a-something
RUN npm run prod:build
RUN echo "FINISHED BUILDING!" 
EXPOSE ${PORT}
CMD ["npm","run","prod:start"]

当我运行npm run prod: build和npm run prod: start时，捆绑包成功构建，但是当我构建docker（上下文是根文件夹）时，出现以下npm错误：

ERROR in Entry module not found: Error: Can't resolve 'babel-loader' in '/src/packages/a-something'
npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! a-something@1.0.0 prod:build: `webpack --config webpack.config.js`
npm ERR! Exit status 2
npm ERR! 
npm ERR! Failed at the a-something@1.0.0 prod:build script.

我的主机操作系统是macOS Mojave。也许Lerna生成的符号链接在Debian（由节点image使用）上的处理方式有所不同？

更新：通过将所有与babel相关的npm软件包从root package.json的devDependencies移至dependencies部分，解决了该问题。有谁知道为什么这可以解决问题？