httpegress

The HTTP egress proxy is a core microservice that relays HTTP requests to external non-Microbus URLs. It is a thin wrapper over the standard net/http client but provides the following benefits:

Requests are easily mockable in tests
The time budget is correctly taken into account
Telemetry is captured and visualized by Grafana

To make a request via the egress proxy, use Get, Post or Do methods of the client. To set a timeout shorter than the time budget of the current context, use context.WithTimeout. For example:

req, _ := http.NewRequest("DELETE", "https://example.com/ex/5", nil)
req.Header.Set("Authorization", "Bearer " + token)
shortCtx, cancel := context.WithTimeout(ctx, 4*time.Second)
resp, err := httpegressapi.NewClient(svc).Do(shortCtx, req)
cancel()
if err != nil {
	return err
}

To mock the egress microservice, create Mock of it and handle the request manually:

	mock := NewMock()
	mock.MockMakeRequest = func(w http.ResponseWriter, r *http.Request) (err error) {
		req, _ := http.ReadRequest(bufio.NewReader(r.Body))
		if req.Method == "DELETE" && req.URL.String() == "https://example.com/ex/5" {
			w.Header().Set("Content-Type", "application/json")
			w.Write([]byte(`{"deleted":true}`))
		} else {
			w.WriteHeader(http.StatusNotFound)
		}
		return nil
	}

Note that the single endpoint of the HTTP egress microservice MakeRequest is listening on internal Microbus port :444 rather than :443. That is because port :443 is open by default to the outside via the HTTP ingress proxy.

httpegress

See Also