Method ServeHTTP

tools/querytee/proxy_endpoint.go:52–72

(w http.ResponseWriter, r *http.Request)

}

func (p *ProxyEndpoint) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	level.Debug(p.logger).Log("msg", "Received request", "path", r.URL.Path, "query", r.URL.RawQuery)

	// Send the same request to all backends.
	resCh := make(chan *backendResponse, len(p.backends))
	go p.executeBackendRequests(r, resCh)

	// Wait for the first response that's feasible to be sent back to the client.
	downstreamRes := p.waitBackendResponseForDownstream(resCh)

	if downstreamRes.err != nil {
		http.Error(w, downstreamRes.err.Error(), http.StatusInternalServerError)
	} else {
		w.WriteHeader(downstreamRes.status)
		if _, err := w.Write(downstreamRes.body); err != nil {
			level.Warn(p.logger).Log("msg", "Unable to write response", "err", err)
		}
	}

	p.metrics.responsesTotal.WithLabelValues(downstreamRes.backend.name, r.Method, p.routeName).Inc()
}

func (p *ProxyEndpoint) executeBackendRequests(r *http.Request, resCh chan *backendResponse) {
	responses := make([]*backendResponse, 0, len(p.backends))