Extension mechanism for HTTP filters based on dynamic loading

[dmitriyilin]

Envoy currently provides extension mechanisms based on WASM and Lua. Approach for GoLang is under discussion as well: #15152.

Taking into account that small footprint, high performance are essential for using Envoy as a sidecar and ongoing work on GoLang extension (#22573), it looks reasonable to work on support for extension mechanism based on dynamic loading as well. For example, for using Rust as the language for creating custom filters (#12155). Envoy already has support for dynamically loading opentracing libraries: #2252.

What's your opinion regarding introducing such an extension mechanism for HTTP filters?

[mattklein123]

Dynamic loading is tracked here: #2053.

There is no objection to add this but someone needs to do the work.

I would like to see native Rust filter support but that is orthogonal IMO. Static linking for that would work fine also.

[dmitriyilin]

Thanks for the link to the original dynamic loading issue!

Indeed, "support" for Rust in not tightly coupled. Added it just as one of the possible ways to start adoption of the language.

Can we leave this issue open? It's nice to keep a global goal of supporting various loadable Envoy modules during design, but can be handy to have smaller goal to make some progress.

[mattklein123]

Sure that's fine.