zjh-blog

A long‑running backend that evaluates Python code must solve one problem well: switching the active interpreter or virtual environment at runtime without restarting the host process. A reliable solution depends on five pillars: unambiguous input semantics, reproducible version discovery, version‑aware initialization, disciplined management of process environment and sys.path, and transactional switching that can roll back safely on failure. The pythonserver implementation demonstrates each of these pillars in a way that is both practical and portable. The switching workflow begins with a single resolver that accepts either an interpreter executable path or a virtual environment directory. If the input is a file whose basename looks like a Python executable, the resolver treats it as such, and when the path sits under bin or Scripts it walks one directory up to infer the venv root. If the input is a directory, the resolver confirms a venv by checking for pyvenv.cfg or conda‑meta. Inputs...

  Project Structure of Virtual Environments Created with virtualenv or venv When we create a Python virtual environment, the system automatically generates a complete directory structure to isolate project dependencies. As shown in the image, the venv1 virtual environment contains several core directories, each serving specific functions. Core Directory Overview The virtual environment's root directory contains four main directories: bin , include , lib , and lib64 , along with an important configuration file pyvenv.cfg . This structure design mimics the layout of system-level Python installations, ensuring environment integrity and independence. bin Directory: Executable File Hub The bin directory is the execution center of the virtual environment, containing all executable files and scripts. The most important among these are various activation scripts, such as activate.csh , activate.fish , and activate.ps1 , which correspond to different shell environments. When you exec...