npm can't find package.json when running docker container with compose

Question

I am trying to wire up my Angular 7 client app into docker compose locally.

I get the following error when I docker-compose up:

client-app    | npm ERR! errno -2
client-app    | npm ERR! syscall open
client-app    | npm ERR! enoent ENOENT: no such file or directory, open '/app/package.json'

Dockerfile:

FROM node:9.6.1

RUN mkdir -p /app
WORKDIR /app
EXPOSE 4200

ENV PATH /app/node_modules/.bin:$PATH

COPY . /app

RUN npm install --silent
RUN npm rebuild node-sass

CMD ["npm", "run", "docker-start"]

The compose part for the client is:

  client-app:
    image: ${DOCKER_REGISTRY-}client
    container_name: client-app
    ports:
      - "4200:81"
    build:
      context: .
      dockerfile: ClientApp/Dockerfile

package.json is in the ClientApp folder along-side Dockerfile, I would assume COPY . /app should copy the package.json to the container. I don't have any excludes in dockerignore. I am using Docker for Windows with Unix containers. I tried npm init before (but that will create an empty package.json anyway) and looked through the SO posts but most of the dockerfile definitions look exactly the same. I also tried: COPY package*.json ./ additionally and building the image with --no-cache.

Answer 1

Your Dockerfile is fine, and COPY package*.json ./ is not necessary - its being copied with your entire app.

The problem is in your docker-compose file.

you defined:

build:
      context: .
      dockerfile: ClientApp/Dockerfile

that means, your Dockerfile will accept the docker-compose context, which is 1 directory above:

├── docker-compose.yml -- this is the actual context
└── ClientApp
    ├── Dockerfile -- this is the expected context

so when the CMD is running, it is 1 directory above the package.json, therefore it cannot run the command and the container exits.

to fix it, give your docker-compose file the correct context:

build:
      context: ClientApp
      dockerfile: Dockerfile

and it should work.

Answer 2

This command COPY package*.json ./ will try copy package.json from root dir. However looks like you need to copy package.json from ClientApp dir

Two way to fix this: 1) Change compose file context: ./ClientApp/ 2) Change docker file COPY ./ClientApp/package.json /app/package.json

I think better to change docker file because in feature you may want to copy some file from root dir