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 ?
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.
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.
print statement does not need the vast power over the host that --privileged gives (for example it gives the power to shut down the host). /dev/stdout is usually just a link to /proc/self/fd/1, which is to say, it's the process's normal standard output; you don't even need a device file to write there.
docker logsto see output of the containers-dflag when doingdocker runand output should be printed to stdout