Method DecodeLabelsForMetrics

decoder/decoder.go:103–135

DecodeLabelsForMetrics transforms eBPF map key bytes into a list of label values according to configuration (different label sets require different names). This decoder method variant does caching and is suitable for metrics.

(in []byte, name string, labels []config.Label)

// according to configuration (different label sets require different names).
// This decoder method variant does caching and is suitable for metrics.
func (s *Set) DecodeLabelsForMetrics(in []byte, name string, labels []config.Label) ([]string, error) {
	s.mu.Lock()
	defer s.mu.Unlock()

	cache, ok := s.cache[name]
	if !ok {
		cache = map[string][]string{}
		s.cache[name] = cache
	}

	// string(in) must not be a variable to avoid allocation:
	// * https://github.com/golang/go/commit/f5f5a8b6209f8
	if cached, ok := cache[string(in)]; ok {
		return cached, nil
	}

	// Also check the skip cache if the input would have return ErrSkipLabelSet
	// and return the error early.
	if s.skipCache != nil {
		if _, ok := s.skipCache.Get(string(in)); ok {
			return nil, ErrSkipLabelSet
		}
	}

	values, err := s.decodeLabels(in, labels)
	if err != nil {
		return nil, err
	}

	cache[string(in)] = values

	return values, nil
}

// DecodeLabelsForTracing transforms eBPF map key bytes into a list of label values
// according to configuration (different label sets require different names).