Method ServeHTTP

pkg/frontend/transport/handler.go:241–368

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

}

func (f *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	var (
		stats       *querier_stats.QueryStats
		queryString url.Values
	)

	tenantIDs, err := users.TenantIDs(r.Context())
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	userID := users.JoinTenantIDs(tenantIDs)
	source := tripperware.GetSource(r)

	if f.tenantFederationCfg.Enabled {
		maxTenant := f.tenantFederationCfg.MaxTenant
		if maxTenant > 0 && len(tenantIDs) > maxTenant {
			if f.cfg.QueryStatsEnabled {
				f.rejectedQueries.WithLabelValues(reasonTooManyTenants, source, userID).Inc()
			}
			http.Error(w, fmt.Errorf(tenantfederation.ErrTooManyTenants, maxTenant, len(tenantIDs)).Error(), http.StatusBadRequest)
			return
		}
	}

	// Initialise the stats in the context and make sure it's propagated
	// down the request chain.
	if f.cfg.QueryStatsEnabled {
		// Check if querier stats is enabled in the context.
		stats = querier_stats.FromContext(r.Context())
		if stats == nil {
			var ctx context.Context
			stats, ctx = querier_stats.ContextWithEmptyStats(r.Context())
			r = r.WithContext(ctx)
		}
	}

	defer func() {
		_ = r.Body.Close()
	}()

	// Buffer the body for later use to track slow queries.
	var buf bytes.Buffer
	r.Body = http.MaxBytesReader(w, r.Body, f.cfg.MaxBodySize)
	r.Body = io.NopCloser(io.TeeReader(r.Body, &buf))
	// We parse form here so that we can use buf as body, in order to
	// prevent https://github.com/cortexproject/cortex/issues/5201.
	// Exclude remote read here as we don't have to buffer its body.
	isRemoteRead := strings.Contains(r.URL.Path, "api/v1/read")
	if !isRemoteRead {
		if err := r.ParseForm(); err != nil {
			statusCode := http.StatusBadRequest
			if util.IsRequestBodyTooLarge(err) {
				statusCode = http.StatusRequestEntityTooLarge
			}
			http.Error(w, err.Error(), statusCode)
			if f.cfg.QueryStatsEnabled && util.IsRequestBodyTooLarge(err) {