Containerised celery worker won't start on docker-compose up

Question

My knowledge to docker is pretty limited so I came here posting this celery worker service won't start with the following error:

ERROR: for api_worker_1 Cannot start service worker: b'OCI runtime create failed: container_linux.go:348: starting container process caused "exec: \"worker\": executable file not found in $PATH": unknown'

DockerFile

# web
FROM python:2.7
RUN apt-get update
RUN apt-get install -y swig
RUN apt-get install -y libssl1.0-dev
RUN pip install --upgrade pip
ADD . /app
WORKDIR /app
CMD ["python", "-u","app.py"]

docker-compose.yml

version: '2' 
services:

  db:
    image: postgres
    restart: always
    volumes:
      - ./postgres-data:/var/lib/postgresql/data
    ports:
      - "5432:5432"

  web:
    restart: always
    build: .
    volumes:
      - ./web:/data/web
      - .:/app
    command: python -u app.py
    ports:
     - "5000:5000"

  rabbit:
    hostname: rabbit
    image: rabbitmq:latest
    environment:
      - RABBITMQ_DEFAULT_USER=guest
      - RABBITMQ_DEFAULT_PASS=guest
    ports:
      - "5672:5672"

  worker:
    restart: always
    build: .
    volumes:
      - .:/app
    command: celery worker -B -l info -A app.tasks.celery
    links:
      - db
      - rabbit
      - web
    depends_on:
      - web

Looking at the worker service:

  worker:
    restart: always
    build: .
    volumes:
      - .:/app
    command: celery worker -B -l info -A app.tasks.celery

I'm not using/installing the celery from docker. As this is rather a worker image instead of celery image.

This is running with flask application and it was recently working. After cleaning up or deleting images and containers. Running docker-compose build and docker-compose up yield the

OCI runtime create failed:..

Error afterward.

UPDATE

I updated the title of the question because celery title is misleading here. This is rather a worker service which doesn't have a DockerFile on it. It is a service to start a celery worker which resides on app/tasks/celery.

Answer 1

In your docker-compose file, you have specified the same build context (build: .) for both web and worker. The Dockerfile you posted above is being used to build the web image AND the worker image, and clearly celery is not installed in that image.