CEL

Google's Common Expression Language (CEL) provides fast, portable, and safe expression evaluation for policy enforcement and data filtering.

CEL is a non-Turing complete language designed for speed and security, executing in linear time with zero side effects. It integrates seamlessly into distributed systems like Kubernetes for Admission Control and Istio for attribute-based policies. By using a C++ or Go runtime, CEL evaluates complex logic (e.g., checking if a request size is under 5MB or if a user has a 'prod' tag) without the overhead or risks of a full scripting engine.

https://github.com/google/cel-spec