configure-modifyresponse.go

proxy := httputil.NewSingleHostReverseProxy(u)
// Configure proxy.Director ...

// ModifyResponse runs before forwarding the downstream response back to the client
proxy.ModifyResponse = func(res *http.Response) error {
	responseContent := map[string]interface{}{}
	err := parseResponse(res, &responseContent)
	if err != nil {
		return err
	}

	return captureMetrics(responseContent)
}