gistfile1.go

// This callback accumulates the microsecond duration of the reporting
// framework's overhead such that it can be reported.
var requestLatencyAccumulator = func(began time.Time) {
  microseconds := float64(time.Since(began) / time.Microsecond)

	requestLatency.Add(nil, microseconds)
}

func (registry registry) Handler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		defer requestLatencyAccumulator(time.Now())

		requestCount.Increment(nil)
		url := r.URL

		if strings.HasSuffix(url.Path, jsonSuffix) {
			header := w.Header()
			header.Set(ProtocolVersionHeader, APIVersion)
			header.Set(contentTypeHeader, jsonContentType)

			writer := decorateWriter(r, w)

			if closer, ok := writer.(io.Closer); ok {
				defer closer.Close()
			}

			registry.dumpToWriter(writer)

		} else {
			w.WriteHeader(http.StatusNotFound)
		}
	}
}