NodeJs将软件包复制到Docker映像

Question

我遵循了文件结构

...
   - public
   - app
   - docker/
        - node-js/Dockerfile
   docker-compose.yml
   package.json

在我的dockerfile中，我有一个逻辑来复制package.json并运行npm install

FROM node:12.0.0-alpine

MAINTAINER Bogdan Dubyk <bogdan.dubyk@gmail.comn>

COPY package.json /var/www/frontend/
RUN npm install

CMD [ "npm", "start" ]

但是在构建映像时出现错误ERROR: Service 'node-js' failed to build: COPY failed: stat /var/lib/docker/tmp/docker-builder184577258/package.json: no such file or directory，看起来像Dockerfile只是在自己的文件夹中查找文件？是否可以从文件夹外部复制文件？

我尝试了COPY ../../package.json /var/www/frontend/，但也遇到了错误ERROR: Service 'node-js' failed to build: COPY failed: Forbidden path outside the build context: ../../package.json ()