docker run failed at “python3: can’t open file”

My code is in directory /test-scripts, details structure is as follows.

/test-scripts
│___Dockerfile 
│
└───requirements.txt
....
|
└───IssueAnalyzer.py

Run the following command in directory /test-scripts.

/test-scripts(master)>

docker run --rm -p 5000:5000 --name testdockerscript testdockerscript:1.0
python3: can't open file '/testdocker/IssueAnalyzer.py -u $user -p $pwd': [Errno 2] No such file or directory

And my Dockerfile content is as follows.

FROM python:3.6-buster

ENV PROJECT_DIR=/testdocker

WORKDIR $PROJECT_DIR

COPY requirements.txt $PROJECT_DIR/.

RUN apt-get update 
    && apt-get -yy install libmariadb-dev

RUN pip3 install -r requirements.txt

COPY . $PROJECT_DIR/.

CMD ["python3", "/testdocker/IssueAnalyzer.py -u $user -p $pwd"]

Use $user, $pwd above to replace the real value in this question. In my opinion, the file IssueAnalyzer.py will be copy from current directory /test-scripts to /testdocker, but actually it is not. Please help to let me know how to change this Dockerfile. Thanks!

Answer

You have 2 different way to define the CMD: exec form and shell form.

You’re using the exec form but you’re not splitting the command correctly.

For this specific case, I suggest to use the shell form:

[...]

CMD python3 /testdocker/IssueAnalyzer.py -u $user -p $pwd

If you really want to use the exec form:

[...]

CMD ["python3", "/testdocker/IssueAnalyzer.py", "-u $user", "-p $pwd"]

Reference: https://docs.docker.com/engine/reference/builder/#cmd