Envoy Lua HTTP Filter Exploration

Envoy offers a of variety in HTTP filters and you can do a lot with what comes out of the box like Header Mutation filter or gRPC-HTTP Transcoding. While this is great, there are certain circumstances where we need some additional customizations. To solve this issue, Envoy provides options like Lua HTTP Filter, Wasm Filter or the ExtProc Filter. Through these filters, you can write custom code in a non-C++ language that gets excuted either in the request or response flow like any other Envoy Filter. To start my journey into extending Envoy, I spent some time looking into the Lua HTTP Filter.

…