Summary

In this chapter, we read about Wasm and its use. We learned about how Wasm is used on the web due to its high performance, and we also familiarized ourselves with how to build Wasm using Go and use it from a web browser using JavaScript. Wasm is also becoming a popular choice on the server side, especially among network proxies such as Envoy.

To get a standardized interface for implementing Wasm for proxies, there are the Proxy-Wasm ABI specifications which are low-level specifications describing the interface between Wasm and the proxy hosting the Wasm. Wasm for Envoy needs to be Proxy-Wasm compliant, but the Proxy-Wasm ABIs are difficult to work with; the Proxy-Wasm SDKs are much easier to work with. At the time of writing this chapter, there are many programming languages in which Proxy-Wasm SDK implementations are available, of which Rust, Go, C++, and AssemblyScript are among the most popular. We made use of the Envoy Wasm filter to configure a Wasm on an Envoy HTTP...