Envoy filter for ext_proc not reaching EOF

Question

I am using Istio 1.16 with envoy (v1.24.1)sidecar. I have created a filter for ext_proc (v3) which connect to a remote API and send some health information on each request.

          ext_proc 
             ^
             |
client ->  envoy -> upstream

The ext_proc is using GRPC and sending request header, request body etc... Also the processing mode is given below

          request_header_mode: "SEND"
          response_header_mode: "SEND"
          request_body_mode: "BUFFERED"
          response_body_mode: "BUFFERED"
          request_trailer_mode: "SKIP"
          response_trailer_mode: "SKIP"

With this processing mode configuration the context is not cancelling and the read is not reaching EOF. Therefore, my code which is inside the EOF is not working.

    ctx := srv.Context()
for {
    select {
    case <-ctx.Done():
        return ctx.Err()
    default:
    }
    req, err := srv.Recv()
    if err == io.EOF {
        **send request to remote API**
        return nil
    }
    if err != nil {
        return status.Errorf(codes.Unknown, "cannot receive stream request: %v", err)
    }

But, when i change the response_trailer_mode to SEND the flow is working fine, context get cancelled and EOF satisfies. Whereas, I do not need the response trailer, SKIP is the actual need. The reference code was taken from the below link ext_proc.

How to make this working with the trailer mode SKIP? Any suggestions?

Envoy filter for ext_proc not reaching EOF

0 Answers0