Moving common network functionality such as client load-balancing and circuit-breaking into out-of-process proxies has kickstarted the technology we call Service Mesh, with Istio as its most popular incarnation. With the introduction of WASM support, you can now extend its functionality by writing custom Filters for Istio's proxy, Envoy, in any language that supports WASM. Let's take a closer look at developing, building, and deploying WASM Filters using the example of an OpenID Connect Filter that adds Keycloak Authentication functionality to any service in your Mesh - no code changes required.
