System Compatibility

LangBot's plugin system utilizes mechanisms such as Asyncio and Subprocess, which work well on Unix-like systems (such as Linux, macOS), but have some issues on Windows, preventing plugins from running properly.

Python's asynchronous event loop on Windows defaults to using ProactorEventLoop, but this event loop lacks support for Stdio, while LangBot in non-Docker environments relies on Stdio to communicate with Plugin Runtime, and Plugin Runtime also depends on Stdio to communicate with plugins.

If we switch to using SelectorEventLoop, it would prevent Plugin Runtime and plugins from starting properly, as SelectorEventLoop does not support Subprocess.

For detailed information about these issues, please refer to: Python Official Documentation

Solution

Unlike the tight coupling between subprocess management and Stdio communication on Unix-like systems, LangBot and the Plugin Runtime automatically switch to a hybrid subprocess + WebSocket communication strategy on Windows. LangBot still launches the Plugin Runtime via a subprocess, but communicates with it over WebSocket; similarly, the Plugin Runtime starts each installed plugin via subprocesses while communicating with them through WebSocket.

This behavior is automatically selected based on the OS, so no manual configuration is required.