Docker Compose couldn't find a package.json file in "/app"-CodePudding

Here is my project struture

.
├── README.md
├── docker-compose.yml
└── frontend
    ├── Dockerfile
    ├── README.md
    ├── build
    ├── package.json
    ├── yarn.lock
    └── ...

Docker-compose.yml

version: '3.7'

services:
  frontend:
    build:
      context: frontend
      dockerfile: Dockerfile
    volumes:
      - '.:/app'
      - '/app/node_modules'
    ports:
      - 3000:3000

Dockerfile

FROM node:14-alpine

WORKDIR /app

COPY ./package.json /app/package.json
RUN yarn install --no-lockfile

COPY . .

CMD ["yarn", "start"]

If i build container using docker, it works fine

But docker-compose up --build always returns

Attaching to book-marketplace_frontend_1
frontend_1  | yarn run v1.22.15
frontend_1  | error Couldn't find a package.json file in "/app"
frontend_1  | info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
book-marketplace_frontend_1 exited with code 1

it's weird that docker-compose can still run yarn install ( which needs package.json) but can not locate it later. Hope someone can help me

CodePudding user response：

Because you are already in workdir app as you earlier defined as WORKDIR. So change the line to:

COPY ./package.json /package.json

CodePudding user response：

Your volumes: block is replacing the /app directory in the container with something totally different. (You're using a frontend subdirectory as the build context, but then bind-mounting . over /app; if you docker-compose run frontend ls you'll see a frontend subdirectory and not your application.)

You can resolve this by deleting the volumes: block. Your container will run the code that's built into the image, and not something else. A minimal functional Compose setup can look like

version: '3.8'
services:
  frontend:
    build: frontend
    ports:
      - '3000:3000'