This is a fairly minimal setup that demonstrates remote debugging for Python from one container to another with VS Code using a combination of the official VS Code Python extension and the Remote Container development extension. This is useful because sometimes I don't want to run the editor on my host machine directly but still want to be able to debug a Python script running in another Docker container. For example, my Mac machine may have Python 3 built-in but I want to debug a script that runs Python 2.

This setup has been tested with:

• VS Code: version 1.40.2
• Python extension: version 2019.11.50794
• Remote Container extension: 0.86.0
• Docker Desktop for Mac 2.1.0.5

There are two containers in this setup that each have a volume pointing to the repo's directory:

• editor runs the VS Code editor. This is a bare bone Python image because I don't need that much functionality from this container. The only changes on top of the base image are
  • Addition of the non-root user jovyan for the editor to run under as a best practice.
  • Installation of the ptvsd package, which is installed on both the "local" and "remote" environments for remote debugging to work, and the pep8 package, which is required for autoformatting in VS Code. The latter package is non-essential.
• script runs the script test_script.py that is to be debugged. The base image of this container (jupyter/base-notebook:python-3.7.3) is more complex than the editor's image for demonstration purpose because in reality, the environment in which the script being debugged runs is quite complex as well. This container also has ptvsd installed in order for remote debugging to work.

To use this setup:

• Run docker-compose up -d in the root project directory.
• In VS Code, hit F1, choose "Remote Container: Open Folder in Container" and open the root project directory.
• Hit F5 to start debugging. VS Code should stop in the body of the add function.

Note that once test_script.py has finished executing, the script container will terminate so if you want to try debugging again, you'll have to run docker-compose up -d again.