Export LabelsFromName func from CollectD receiver

receiver/collectdreceiver/collectd.go

@@ -194,7 +194,7 @@ func (r *collectDRecord) pointTypeInstance(attrs map[string]string, parts []byte
 		return parts
 	}
 
-	instanceName, extractedAttrs := labelsFromName(r.TypeInstance)
+	instanceName, extractedAttrs := LabelsFromName(r.TypeInstance)
 	if instanceName != "" {
 		if len(parts) > 0 {
 			parts = append(parts, '.')
@@ -210,13 +210,16 @@ func (r *collectDRecord) pointTypeInstance(attrs map[string]string, parts []byte
 	return parts
 }
 
-// labelsFromName tries to pull out dimensions out of name in the format name[k=v,f=x]-morename
-// would return name-morename and extract dimensions (k,v) and (f,x)
-// if we encounter something we don't expect use original name.
-// This is a bit complicated to avoid allocations, string.split allocates, while slices
-// inside same function, do not.
-func labelsFromName(val *string) (instanceName string, toAddDims map[string]string) {
-	instanceName = *val
+// LabelsFromName tries to pull out dimensions out of name in the format
+// "name[k=v,f=x]-more_name".
+// For the example above it would return "name-more_name" and extract dimensions
+// (k,v) and (f,x).
+// If something unexpected is encountered it returns the original metric name.
+//
+// The code tries to avoid allocation by using local slices and avoiding calls
+// to functions like strings.Slice.
+func LabelsFromName(val *string) (metricName string, labels map[string]string) {
+	metricName = *val
 	index := strings.Index(*val, "[")
 	if index > -1 {
 		left := (*val)[:index]
@@ -244,8 +247,8 @@ func labelsFromName(val *string) (instanceName string, toAddDims map[string]stri
 				prev = cindex + 1
 				cindex = strings.Index(dimensions[prev:], ",") + prev
 			}
-			toAddDims = working
-			instanceName = left + rest
+			labels = working
+			metricName = left + rest
 		}
 	}
 	return
@@ -267,7 +270,7 @@ func parseAndAddLabels(labels map[string]string, pluginInstance *string, host *s
 }
 
 func parseNameForLabels(labels map[string]string, key string, val *string) {
-	instanceName, toAddDims := labelsFromName(val)
+	instanceName, toAddDims := LabelsFromName(val)
 
 	for k, v := range toAddDims {
 		if _, exists := labels[k]; !exists {

receiver/collectdreceiver/collectd_test.go

@@ -384,3 +384,52 @@ var wantMetricsData = []*metricspb.Metric{
 		},
 	},
 }
+
+func TestLabelsFromName(t *testing.T) {
+	tests := []struct {
+		name           string
+		wantMetricName string
+		wantLabels     map[string]string
+	}{
+		{
+			name: "simple",
+			wantMetricName: "simple",
+		},
+		{
+			name: "single[k=v]",
+			wantMetricName: "single",
+			wantLabels: map[string]string{
+				"k": "v",
+			},
+		},
+		{
+			name: "a.b.c.[k=v].d",
+			wantMetricName: "a.b.c..d",
+			wantLabels: map[string]string{
+				"k": "v",
+			},
+		},
+		{
+			name: "a.b[k0=v0,k1=v1,k2=v2].c",
+			wantMetricName: "a.b.c",
+			wantLabels: map[string]string{
+				"k0": "v0", "k1": "v1", "k2": "v2",
+			},
+		},
+		{
+			name: "empty[]",
+			wantMetricName: "empty[]",
+		},
+		{
+			name: "mal.formed[k_no_sep]",
+			wantMetricName: "mal.formed[k_no_sep]",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotMetricName, gotLabels := LabelsFromName(&tt.name)
+			assert.Equal(t, tt.wantMetricName, gotMetricName)
+			assert.Equal(t, tt.wantLabels, gotLabels)
+		})
+	}
+}