Docker和pip要求

Question

I want to maintain the development environment for a python application that needs dependencies installed with pip .

I plan to have the source code (including requirements.txt ) pulled from a git repo into a host folder which is mounted as a docker volume.

Is there a docker pattern to keep the libraries updated and yet avoid the expensive pip install -r requirements.txt with every git pull ?

Answer 1

The way to avoid installing every time is to do the pip install in a separate RUN instruction before you pull the whole repo. To do that you'll need another way to get your requirements.txt into the container - maybe with ADD , specifying the full remote URL:

ADD https://raw.githubusercontent.com/etc/requirements.txt .
RUN pip install -r requirements.txt

When you docker build this, if the contents of requirements.txt hasn't changed then the cached layer with all the installed dependencies will be used. If the requirements file has changed, then the install will run again.

If you go with this, you'll want specific versions in your requirements file, and you'll have to manually update it for version bumps.