grpc-web filter not setting http status code from grpc status

[jwahlin]

I'm using the grpc-web filter and it isn't setting the http status appropriately from the gRPC status. The gRPC status is coming through the response in the trailers since we're using http2.

To replicate the issue, use the grpc-web filter and send a grpc-web request through Envoy that should fail. The grpc-status will be non-zero, but the http status will show 200. I expect envoy to translate the grpc-status trailer to an http status.

[qiwzhang]

@fengli79 ?

[fengli79]

@jwahlin, the grpc status is encoded as response body instead of the http/http2 response code.

https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-WEB.md

HTTP/2 related behavior (specified in gRPC over HTTP2)

1. stream-id is not supported or used
2. go-away is not supported or used

[jwahlin]

Thanks for taking a look at this. I do see the grpc-status included in the response trailers. Just to clarify, you're saying that regardless of the grpc-status, the http status is intended to stay at 200, is that right?

I'm not sure how the stream-id and go-away changes are related.

[fengli79]

Thanks for taking a look at this. I do see the grpc-status included in the response trailers. Just to clarify, you're saying that regardless of the grpc-status, the http status is intended to stay at 200, is that right?
Correct.

I'm not sure how the stream-id and go-away changes are related.
They only exist between envoy and your grpc server. Your downstream is using http to talk with envoy, although its can be http2, but semantically it's http in grpc-web, stream id and go-away is not visible there.

[jwahlin]

Thanks for the information. When we use http (and the grpc_http1_bridge), the grpc-status does determine the http status. When we use http2, the grpc-status does not affect the http status. Are there any plans to add a grpc_http2_bridge that sets the http2 status based on the grpc-status?

[fengli79]

grpc_http1_bridge is not considered as a grpc-web compatible filter.
Yes, someone may add a grpc_http2_bridge as needed, but it's pretty much a different mapping from http/http2 to grpc, different from the grpc-web spec.
With grpc-web, you will use the grpc-web js client to handle status and error, so you don't need to worry about the underlying http status code anymore.

[jwahlin]

Makes sense. Thanks for your time!