Http request middleware function

[OrenLeung]

Why

In order to propagate trace context & headers for distributed tracing, we need some way of "injecting" middleware to our requests

How?

• an parameter was added to the the function that creates a new webrpc client

Tests

• re-generated _examples/golang-basic/generate.gen.go

• webrpc-gen -schema ./_examples/golang-basics/example.ridl -target go -out ./_examples/golang-basics/example.gen.go -client -server -pkg main

• re-generated in internal repos

Communication

• post on slack that if anybody needs makes modifications to internal private repo's ridl, they should git pull, re-build, and reinstalling webrpc

Example Generated Client - _examples/golang-basics

All Generated Client Helpers function will look like this

Type of Function Pointer to Pass as a parameter into Create New Client

[VojtechVitek]

Hi @OrenLeung @miguelvr @kipply,

I'm walking through this fork's Pull Requests and wondering what we could backport to upstream webrpc repo.

Can you please share how this feature is used in a real world example?
Are you setting some request headers based on the context values?

Example from https://rakyll.medium.com/context-propagation-over-http-in-go-d4540996e9b0:

const requestIDHeader = "request-id"

// Transport serializes the request context into request headers.
type Transport struct {
 // Base is the actual round tripper that makes the request.
 // http.DefaultTransport is used if none is set.
 Base http.RoundTripper
}

// RoundTrip converts request context into headers
// and makes the request.
func (t *Transport) RoundTrip(r *http.Request) (*http.Response, error) {
 r = cloneReq(r) // per RoundTrip interface enforces
 
 rid := request.IDFromContext(r.Context())
 if rid != "" {
  r.Header.Add(requestIDHeader, rid)
 }
 
 base := t.Base
 if base == nil {
  base = http.DefaultTransport
 }
 
 return base.RoundTrip(r)
}

Have you considered using custom http.Transport instead? Would it be sufficient?

Thanks!

Best,
Vojtech | https://golang.cz