Add JWT header mutation Wasm extension

[bianpengyuan]

This is to track the work to add Wasm extension which mutates request header based on Jwt Header and recompute route based on the new header. The extension should have unit test coverage, integration test coverage, and guide on how to customize for bespoke needs.

cc @mandarjog

[vigvigneshps1995]

Any idea on when this example will be available ?

[Jonomir]

Hey, I'm looking to develop a plugin for dynamic routing for our istio. This example would be great to get started.
Is there anything available already?

[wxdao]

Hi bianpeng, may I know what is blocking the impl of this extension? Is it about lack of apis in proxy wasm abi?

[bianpengyuan]

what is blocking the impl of this extension? Is it about lack of apis in proxy wasm abi?

No technical reason, just need someone to pick it up. We are adding first class support for jwt based routing at Istio 1.12 (istio/istio#34974), which makes this example less useful, but PR to add this is always welcome.