Activate python virtualenv in Dockerfile

Question

I have a Dockerfile where I try to activate python virtualenv after what, it should install all dependencies within this env. However, everything still gets installed global

Answer 1

There are perfectly valid reasons for using a virtualenv within a container.

You don't necessarily need to activate the virtualenv to install software or use it. Try invoking the executables directly from the virtualenv's bin directory instead:

FROM python:2.7

RUN virtualenv /ve
RUN /ve/bin/pip install somepackage

CMD ["/ve/bin/python", "yourcode.py"]

You may also just set the PATH environment variable so that all further Python commands will use the binaries within the virtualenv as described in https://pythonspeed.com/articles/activate-virtualenv-dockerfile/

FROM python:2.7

RUN virtualenv /ve
ENV PATH="/ve/bin:$PATH"
RUN pip install somepackage

CMD ["python", "yourcode.py"]