~/lightning

Lightning Talk: Beyond Lua: Lightweight Envoy Extension With JavaScript

Lightningat EnvoyCon North America 2025 · on Monday, 2025-11-10· at 12:00· Building B | Level 4 | B406b-407· [javascript, networking]

speaker

name:Takeshi Yoneda

website:https://mathetake.github.io/

resources

video:https://youtu.be/iMtkh37jV7g

slides:none on file

summary

Envoy’s dynamic modules (introduced around Envoy 1.34) load a shared library implementing the Envoy C API so any compiled language can become an HTTP filter. The demo builds a JavaScript dynamic module (prototype using a Go JS engine, recommended production path: Rust + V8), exposes Lua-like callbacks, calls console.log, reads and sets headers, and injects an x-animal header inserted (cat then changed to dog) on responses. Source lives at envoyproxy/dynamic-modules-example and the recorded demo proves it works.

AI-written summary · about

related talks