Function ReadLabels

model/labels/test_utils.go:45–86

ReadLabels reads up to n label sets in a JSON formatted file fn. It is mostly useful to load testing data.

(fn string, n int)

// ReadLabels reads up to n label sets in a JSON formatted file fn. It is mostly useful
// to load testing data.
func ReadLabels(fn string, n int) ([]Labels, error) {
	f, err := os.Open(fn)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)
	b := NewScratchBuilder(0)

	var mets []Labels
	hashes := map[uint64]struct{}{}
	i := 0

	for scanner.Scan() && i < n {
		b.Reset()

		r := strings.NewReplacer("\"", "", "{", "", "}", "")
		s := r.Replace(scanner.Text())

		for labelChunk := range strings.SplitSeq(s, ",") {
			split := strings.Split(labelChunk, ":")
			b.Add(split[0], split[1])
		}
		// Order of the k/v labels matters, don't assume we'll always receive them already sorted.
		b.Sort()
		m := b.Labels()

		h := m.Hash()
		if _, ok := hashes[h]; ok {
			continue
		}
		mets = append(mets, m)
		hashes[h] = struct{}{}
		i++
	}

	if i != n {
		return mets, fmt.Errorf("requested %d metrics but found %d", n, i)
	}
	return mets, nil
}