How to get envoy environment variables in the Proxy-Wasm extension?

[Echo-Van]

I need to get wordload instance information in proxy-wasm extension. I have tried to get these information through environment variables and reading files(such as /etc/istio/pod/labels) mounted by envoy, but all have failed. Can someone help me?

[mathetake]

• First of all, we need to put TinyGo's WASI target forward to support os.Getenv through WASI's get_environ interface.
  • WebAssembly binary built targeting the WASI interface cannot read environment variables tinygo-org/tinygo#1504
• Proxy-Wasm spec is yet to have specification or consensus with regard to environment variables, and currently proxy-wasm-cpp-host leave it just "unimplemented" as you can see here https://github.com/proxy-wasm/proxy-wasm-cpp-host/blob/b7d3d13d75bb6b50f192252258bb9583bf723fa4/src/exports.cc#L769-L772

That said, we cannot read env variables from Wasm VM sides regardless of the languages we use right now.

I will file an issue in Proxy-Wasm's spec repository, and please stay tuned there. Thanks!

[Echo-Van]

@mathetake Thanks for you help. I will stay tuned there.

[mathetake]

resolved in proxy-wasm/proxy-wasm-cpp-host#126 and envoyproxy/envoy#15136