fix(outputs.nebius_cloud_monitoring): Replace reserved label names (#13597)

Co-authored-by: Thomas Casteleyn <thomas.casteleyn@me.com>

plugins/outputs/nebius_cloud_monitoring/README.md

@@ -34,3 +34,55 @@ Folder ID from instance metadata. In this plugin we use [Google Cloud notation]
 This internal metadata endpoint is only accessible for VMs from the cloud.
 
 [Google Cloud notation]: https://nebius.com/il/docs/compute/operations/vm-info/get-info#gce-metadata
+
+### Reserved Labels
+
+Nebius Monitoring backend using json format to receive the metrics:
+
+```json
+{
+  "name": "metric_name",
+  "labels": {
+    "key": "value",
+    "foo": "bar"
+  },
+  "ts": "2023-06-06T11:10:50Z",
+  "value": 0
+}
+```
+
+But key of label cannot be `name` because it's reserved for `metric_name`.
+
+So this payload:
+
+```json
+{
+  "name": "systemd_units_load_code",
+  "labels": {
+    "active": "active",
+    "host": "vm",
+    "load": "loaded",
+    "name": "accounts-daemon.service",
+    "sub": "running"
+  },
+  "ts": "2023-06-06T11:10:50Z",
+  "value": 0
+}
+```
+
+will be replaced with:
+
+```json
+{
+  "name": "systemd_units_load_code",
+  "labels": {
+    "active": "active",
+    "host": "vm",
+    "load": "loaded",
+    "_name": "accounts-daemon.service",
+    "sub": "running"
+  },
+  "ts": "2023-06-06T11:10:50Z",
+  "value": 0
+}
+```

plugins/outputs/nebius_cloud_monitoring/nebius_cloud_monitoring.go

@@ -142,7 +142,7 @@ func (a *NebiusCloudMonitoring) Write(metrics []telegraf.Metric) error {
 				nebiusCloudMonitoringMetrics,
 				nebiusCloudMonitoringMetric{
 					Name:   m.Name() + "_" + field.Key,
-					Labels: m.Tags(),
+					Labels: replaceReservedTagNames(m.Tags()),
 					TS:     m.Time().Format(time.RFC3339),
 					Value:  value,
 				},
@@ -242,3 +242,15 @@ func init() {
 		return &NebiusCloudMonitoring{}
 	})
 }
+
+func replaceReservedTagNames(tagNames map[string]string) map[string]string {
+	newTags := make(map[string]string, len(tagNames))
+	for tagName, tagValue := range tagNames {
+		if tagName == "name" {
+			newTags["_name"] = tagValue
+		} else {
+			newTags[tagName] = tagValue
+		}
+	}
+	return newTags
+}

plugins/outputs/nebius_cloud_monitoring/nebius_cloud_monitoring_test.go

@@ -119,6 +119,31 @@ func TestWrite(t *testing.T) {
 				w.WriteHeader(http.StatusOK)
 			},
 		},
+		{
+			name:   "label with name 'name' is replaced with '_name'",
+			plugin: &NebiusCloudMonitoring{},
+			metrics: []telegraf.Metric{
+				testutil.MustMetric(
+					"cluster",
+					map[string]string{
+						"name": "accounts-daemon.service",
+					},
+					map[string]interface{}{
+						"value": 9226,
+					},
+					time.Unix(0, 0),
+				),
+			},
+			handler: func(t *testing.T, w http.ResponseWriter, r *http.Request) {
+				message, err := readBody(r)
+				require.NoError(t, err)
+				require.Len(t, message.Metrics, 1)
+				require.Equal(t, "cluster_value", message.Metrics[0].Name)
+				require.Contains(t, message.Metrics[0].Labels, "_name")
+				require.Equal(t, float64(9226), message.Metrics[0].Value)
+				w.WriteHeader(http.StatusOK)
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -137,3 +162,37 @@ func TestWrite(t *testing.T) {
 		})
 	}
 }
+
+func TestReplaceReservedTagNames(t *testing.T) {
+	tagMap := map[string]string{
+		"name":  "value",
+		"other": "value",
+	}
+	wantTagMap := map[string]string{
+		"_name": "value",
+		"other": "value",
+	}
+
+	type args struct {
+		tagNames map[string]string
+	}
+	tests := []struct {
+		name string
+		args args
+		want map[string]string
+	}{
+		{
+			name: "tagReplacement",
+			args: args{
+				tagNames: tagMap,
+			},
+			want: wantTagMap,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := replaceReservedTagNames(tt.args.tagNames)
+			require.EqualValues(t, tt.want, got)
+		})
+	}
+}