feat: Detected labels - get and filter labels from ingesters

pkg/ingester/ingester.go

@@ -1371,3 +1371,40 @@ func (i *Ingester) GetDetectedFields(_ context.Context, _ *logproto.DetectedFiel
 		},
 	}, nil
 }
+
+// GetDetectedLabels returns map of detected labels and unique values from this ingester
+func (i *Ingester) GetDetectedLabels(ctx context.Context, req *logproto.DetectedLabelsRequest) (*logproto.LabelToValuesResponse, error) {
+	userID, err := tenant.TenantID(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	instance, err := i.GetOrCreateInstance(userID)
+	if err != nil {
+		return nil, err
+	}
+	var matchers []*labels.Matcher
+	if req.Query != "" {
+		matchers, err := syntax.ParseMatchers(req.Query, true)
+		if err != nil {
+			return nil, err
+		}
+		level.Info(i.logger).Log("msg", matchers)
+	}
+
+	labelMap, err := instance.LabelsWithValues(ctx, *req.Start, matchers...)
+
+	if err != nil {
+		return nil, err
+	}
+	result := make(map[string]*logproto.UniqueLabelValues)
+	for label, values := range labelMap {
+		uniqueValues := make([]string, len(values))
+		for v := range values {
+			uniqueValues = append(uniqueValues, v)
+		}
+
+		result[label] = &logproto.UniqueLabelValues{Values: uniqueValues}
+	}
+	return &logproto.LabelToValuesResponse{Labels: result}, nil
+}

pkg/ingester/instance.go

@@ -562,6 +562,8 @@ func (i *instance) Label(ctx context.Context, req *logproto.LabelRequest, matche
 	}
 
 	labels := util.NewUniqueStrings(0)
+	// (shantanu) can create a map here to store label names::values and count the unique values
+	// just return a string to int map
 	err := i.forMatchingStreams(ctx, *req.Start, matchers, nil, func(s *stream) error {
 		for _, label := range s.labels {
 			if req.Values && label.Name == req.Name {
@@ -583,6 +585,32 @@ func (i *instance) Label(ctx context.Context, req *logproto.LabelRequest, matche
 	}, nil
 }
 
+type UniqueValues map[string]struct{}
+
+// LabelsWithValues returns the label names with all the unique values depending on the request
+func (i *instance) LabelsWithValues(ctx context.Context, startTime time.Time, matchers ...*labels.Matcher) (map[string]UniqueValues, error) {
+	// TODO (shantanu): Figure out how to get the label names from index directly when no matchers are given.
+
+	labelMap := make(map[string]UniqueValues)
+	err := i.forMatchingStreams(ctx, startTime, matchers, nil, func(s *stream) error {
+		for _, label := range s.labels {
+			v, exists := labelMap[label.Name]
+			if !exists {
+				v = make(map[string]struct{})
+			}
+			if label.Value != "" {
+				v[label.Value] = struct{}{}
+			}
+			labelMap[label.Name] = v
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return labelMap, nil
+}
+
 func (i *instance) Series(ctx context.Context, req *logproto.SeriesRequest) (*logproto.SeriesResponse, error) {
 	groups, err := logql.MatchForSeriesRequest(req.GetGroups())
 	if err != nil {