Surprising subtleties of Docker permissions

The analysis platform relies on a modular architecture where each analyzer operates in its own Docker image, accommodating various languages and libraries, with the Dockerfile provided by the analysis author. Inputs are supplied through the /analysis/inputs folder, and outputs are retrieved from /analysis/output, typically using a bind-mounted directory on the host. However, when running in a CircleCI environment, docker cp is utilized due to the remote docker daemon setup, which separates the image execution from the initiating code. This setup initially worked well but encountered issues related to filesystem permissions when deployed on Linux hosts, necessitating a deeper understanding of the POSIX filesystem access control model shared by systems like macOS, BSD, and Linux. This model manages file access through a system of user IDs and group IDs, allowing different permission levels for owners, group members, and other users, which can affect the read, write, or execute capabilities on files and directories.