Method ServeHTTP

pkg/ring/http.go:129–211

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

}

func (r *Ring) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	if req.Method == http.MethodPost {
		ingesterID := req.FormValue("forget")
		if err := r.forget(req.Context(), ingesterID); err != nil {
			level.Error(r.logger).Log("msg", "error forgetting instance", "err", err)
		}

		// Implement PRG pattern to prevent double-POST and work with CSRF middleware.
		// https://en.wikipedia.org/wiki/Post/Redirect/Get

		// http.Redirect() would convert our relative URL to absolute, which is not what we want.
		// Browser knows how to do that, and it also knows real URL. Furthermore it will also preserve tokens parameter.
		// Note that relative Location URLs are explicitly allowed by specification, so we're not doing anything wrong here.
		w.Header().Set("Location", "#")
		w.WriteHeader(http.StatusFound)

		return
	}

	r.mtx.RLock()
	defer r.mtx.RUnlock()

	ingesterIDs := []string{}
	for id := range r.ringDesc.Ingesters {
		ingesterIDs = append(ingesterIDs, id)
	}
	sort.Strings(ingesterIDs)

	storageLastUpdate := r.KVClient.LastUpdateTime(r.key)
	var ingesters []ingesterDesc
	numTokens, ownedByAz := r.countTokensByAz()
	_, owned := r.countTokens()

	for _, id := range ingesterIDs {
		ing := r.ringDesc.Ingesters[id]
		heartbeatTimestamp := time.Unix(ing.Timestamp, 0)
		state := ing.State.String()
		if !r.IsHealthy(&ing, Reporting, storageLastUpdate) {
			state = unhealthy
		}

		// Format the registered timestamp.
		registeredTimestamp := ""
		if ing.RegisteredTimestamp != 0 {
			registeredTimestamp = ing.GetRegisteredAt().String()
		}

		var ownership float64
		var deltaOwnership float64

		if r.cfg.ZoneAwarenessEnabled {
			ownership = (float64(ownedByAz[id]) / float64(math.MaxUint32+1)) * 100
			expectedOwnership := 1 / float64(len(numTokens[ing.Zone])) * 100
			deltaOwnership = (1 - expectedOwnership/ownership) * 100
		} else {
			ownership = (float64(owned[id]) / float64(math.MaxUint32+1)) * 100
			expectedOwnership := 1 / float64(len(owned)) * 100
			deltaOwnership = (1 - expectedOwnership/ownership) * 100