Method ServeHTTP

tsweb/tsweb.go:498–594

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

}

func (h logHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// If there's already a logHandler up the chain, skip this one.
	ctx := r.Context()
	if errCallback.Has(ctx) {
		h.h.ServeHTTP(w, r)
		return
	}

	msg := AccessLogRecord{
		Time:       h.opts.Now(),
		RemoteAddr: r.RemoteAddr,
		Proto:      r.Proto,
		TLS:        r.TLS != nil,
		Host:       r.Host,
		Method:     r.Method,
		RequestURI: r.URL.RequestURI(),
		UserAgent:  r.UserAgent(),
		Referer:    r.Referer(),
		RequestID:  RequestIDFromContext(r.Context()),
	}

	if bs := h.opts.BucketedStats; bs != nil && bs.Started != nil && bs.Finished != nil {
		bucket := bs.bucketForRequest(r)
		var startRecorded bool
		switch v := bs.Started.Map.Get(bucket).(type) {
		case *expvar.Int:
			// If we've already seen this bucket for, count it immediately.
			// Otherwise, for newly seen paths, only count retroactively
			// (so started-finished doesn't go negative) so we don't fill
			// this LabelMap up with internet scanning spam.
			v.Add(1)
			startRecorded = true
		}
		defer func() {
			// Only increment metrics for buckets that result in good HTTP statuses
			// or when we know the start was already counted.
			// Otherwise they get full of internet scanning noise. Only filtering 404
			// gets most of the way there but there are also plenty of URLs that are
			// almost right but result in 400s too. Seem easier to just only ignore
			// all 4xx and 5xx.
			if startRecorded {
				bs.Finished.Add(bucket, 1)
			} else if msg.Code < 400 {
				// This is the first non-error request for this bucket,
				// so count it now retroactively.
				bs.Started.Add(bucket, 1)
				bs.Finished.Add(bucket, 1)
			}
		}()
	}

	if fn := h.opts.OnStart; fn != nil {
		fn(r, msg)
	}

	// Let errorHandler tell us what error it wrote to the client.
	r = r.WithContext(errCallback.WithValue(ctx, func(e HTTPError) {
		// Keep the deepest error.