Method labelNames

web/api/v1/api.go:775–850

(r *http.Request)

}

func (api *API) labelNames(r *http.Request) apiFuncResult {
	limit, err := parseLimitParam(r.FormValue("limit"))
	if err != nil {
		return invalidParamError(err, "limit")
	}

	start, err := parseTimeParam(r, "start", MinTime)
	if err != nil {
		return invalidParamError(err, "start")
	}
	end, err := parseTimeParam(r, "end", MaxTime)
	if err != nil {
		return invalidParamError(err, "end")
	}

	matcherSets, err := api.parseMatchersParam(r.Form["match[]"])
	if err != nil {
		return apiFuncResult{nil, &apiError{errorBadData, err}, nil, nil}
	}

	hints := &storage.LabelHints{
		Limit: toHintLimit(limit),
	}

	q, err := api.Queryable.Querier(timestamp.FromTime(start), timestamp.FromTime(end))
	if err != nil {
		return apiFuncResult{nil, returnAPIError(err), nil, nil}
	}
	defer q.Close()

	var (
		names    []string
		warnings annotations.Annotations
	)
	if len(matcherSets) > 1 {
		labelNamesSet := make(map[string]struct{})

		for _, matchers := range matcherSets {
			vals, callWarnings, err := q.LabelNames(r.Context(), hints, matchers...)
			if err != nil {
				return apiFuncResult{nil, returnAPIError(err), warnings, nil}
			}

			warnings.Merge(callWarnings)
			for _, val := range vals {
				labelNamesSet[val] = struct{}{}
			}
		}

		// Convert the map to an array.
		names = make([]string, 0, len(labelNamesSet))
		for key := range labelNamesSet {
			names = append(names, key)
		}
		slices.Sort(names)
	} else {
		var matchers []*labels.Matcher
		if len(matcherSets) == 1 {