Node.js 找不到在 docker compose 环境中运行的 node js 应用程序的模块

我很抱歉我的问题非常新手，但我有一个可怕的一天发现这个错误，我有一个快速的应用程序，我正试图在docker compose运行它.

FROM mhart/alpine-node
RUN mkdir -p /usr/src/app
RUN chmod -R 777 /usr/src/app
WORKDIR /usr/src/app
RUN npm install node-gyp -g
RUN npm install nodemon -g
ENV NODE_ENV development
EXPOSE 3000

我的docker compose文件的这一部分:

backend:
    mem_limit: 100m
    build:
      context: .
      dockerfile: dockerfiles/node/Dockerfile
    command: npm start
    depends_on:
      - mongo
      - elasticsearch
    volumes:
      - ./backend/:/usr/src/app
    ports:
      - 3000:3000
    links:
      - "mongo:mongo"
      - "elasticsearch:elasticsearch"

当我编写docker compose时，会出现以下错误:

backend_1        | npm info it worked if it ends with ok
backend_1        | npm info using npm@3.10.10
backend_1        | npm info using node@v6.9.5
backend_1        | npm info lifecycle service-designer@1.0.0~prestart: service-designer@1.0.0
backend_1        | npm info lifecycle service-designer@1.0.0~start: service-designer@1.0.0
backend_1        | 
backend_1        | > service-designer@1.0.0 start /usr/src/app
backend_1        | > nodemon index.js
backend_1        | 
backend_1        | [nodemon] 1.11.0
backend_1        | [nodemon] to restart at any time, enter `rs`
backend_1        | [nodemon] watching: *.*
backend_1        | [nodemon] starting `node index.js`
backend_1        | module.js:471
backend_1        |     throw err;
backend_1        |     ^
backend_1        | 
backend_1        | Error: Cannot find module 'dotenv'
backend_1        |     at Function.Module._resolveFilename (module.js:469:15)
backend_1        |     at Function.Module._load (module.js:417:25)
backend_1        |     at Module.require (module.js:497:17)
backend_1        |     at require (internal/module.js:20:19)
backend_1        |     at Object.<anonymous> (/usr/src/app/index.js:1:63)
backend_1        |     at Module._compile (module.js:570:32)
backend_1        |     at Object.Module._extensions..js (module.js:579:10)
backend_1        |     at Module.load (module.js:487:32)
backend_1        |     at tryModuleLoad (module.js:446:12)
backend_1        |     at Function.Module._load (module.js:438:3)
backend_1        | [nodemon] app crashed - waiting for file changes before starting...

如果我在backend容器中输入ls -al，我会得到一个完整的后端应用程序文件夹内容列表，但听起来似乎无法识别 node _模块的依赖关系.