docker-compose 调试服务在运行时显示“pwd”和“ls -l”？

Question

I have a docker-compose file with a service called 'app'. When I try to run my docker file I don't see the service with docker ps but I do with docker ps -a .

I looked at the logs:

docker logs my_app_1
python: can't open file '//apps/index.py': [Errno 2] No such file or directory

In order to debug I wanted to be able to see the home directory and the files and dirs contained there when the app attempts to run.

Is there a command I can add to docker-compose that would show me the pwd and ls -l of the container when it attempts to run index.py ?

My Dockerfile:

FROM python:3
COPY . .
RUN pip install -r requirements.txt
CMD ["python", "apps/index.py"]

My docker-compose.yaml:

version: '3.1'

services:
  app:
    build:
      context: ./app
      dockerfile: ./Dockerfile
    depends_on:
      - db
    ports:
      - 8050:8050

My directory structure:

my_app:
      * docker-compose.yaml
      * app
        * Dockerfile
        * apps
          * index.py

Answer 1

You can add a RUN statement in the application Dockerfile to run these commands. Example:

FROM python:3
COPY . .
RUN pip install -r requirements.txt

# Run your commands
RUN pwd && ls -l

CMD ["python", "apps/index.py"]

Then you chan check the logs of the build process and view the results. I hope this answer helps you.

Answer 2

If you're just trying to debug an image you've already built, you can docker-compose run an alternate command:

docker-compose run apps \
  ls -l ./apps

You don't need to modify anything in your Dockerfile to be able to do this (assuming it uses CMD correctly; see below).

If you need to do more intensive debugging, you can docker-compose run apps sh (or, if your image has it, bash ) to get an interactive shell. The container will include any mounted volumes and be on the same Docker network as the named container, but won't have published ports.

Note that the command here replaces the CMD in the Dockerfile. If your image uses ENTRYPOINT for its main command, or if it has a complete command split between ENTRYPOINT and CMD (especially, if you have ENTRYPOINT ["python"] ), these need to be combined into a single CMD for this to work. If your ENTRYPOINT is a wrapper script that does some first-time setup and then runs the CMD , this approach will work fine; the debugging ls or sh will run after the first-time setup happens.