First glitch: I had no write access to /tmp/fractal_test/, and then I had to enter the container to download images.

[tcompa]

          First glitch: I had no write access to `/tmp/fractal_test/`, and then I had to enter the container to download images.

Originally posted by @tcompa in #9 (comment)

[tcompa]

I see two ways out:

1. We provide 777 permissions to that folder: would it work both ways? Would files from host-machine user be readable from the container?
2. We incorporate point 2 from proof of principle: run a full example #9 (comment) into the Dockerfile, with a small script.

[tcompa]

As @mfranzon correctly points out, option 2 would not allow a user to use any other input image - then it's best to stick with some version of option 1.

[aangelone2]

The current solution is to use for data exchange the fractal-data/ folder, automatically created in the project root by the host when running make run (before the first execution of the containers).

This folder is mapped to /home/fractal-data/ on the container filesystem, and allows writing and reading of all contained files from both sides (from the host user due to ownership, and from the container due to root's superior permissions).