Python docker 容器使用 print()

Question

Hello I would like to use

print('Hello world')

to see what's going on with some variables, however im using Docker which means by default it's not printing anything. Can someone tell me how I can pass these print commands to the docker container ?

Answer 1

This is because Python buffers its output by default.

An easy way to change this behavior is to use the PYTHONUNBUFFERED=1 environment variable : docker run -e PYTHONUNBUFFERED=1 <your_image>

An other way is to call the python command with the -u option .

Answer 2

Maybe you should run your container with the privileged option to share /dev (therefore, sharing /dev/stdout).

This is working for me:

print.py:

print("Hello world")

Dockerfile:

FROM python
ADD print.py /
ENTRYPOINT ["python",  "/print.py"]

Commands:

$ docker build -t python-test .
$ docker run -it --privileged python-test
Hello world

Hope it helps.