Grumpy: Go running Python!

Google runs millions of lines of Python code. The front-end server that drives and YouTube’s APIs is primarily written in Python, and it serves millions of requests per second! YouTube’s front-end runs on CPython 2.7, so we’ve put a ton of work into improving the runtime and adapting our application to work optimally within it. These efforts have borne a lot of fruit over the years, but we always run up against the same issue: it’s very difficult to make concurrent workloads perform well on CPython.

Grumpy is a Python to Go source code transcompiler and runtime that is intended to be a near drop in replacement for CPython. The key difference is that it compiles Python source code to Go source code which is then compiled to native code, rather than to bytecode. This means that Grumpy has no VM. The compiled Go source code is a series of calls to the Grumpy runtime, a Go library serving a similar purpose to the Python C API.