fix: csv output for non indexable metrics

output/csv/output.go

@@ -48,6 +48,20 @@ func newOutput(params output.Params) (*Output, error) {
 	ignoredTags := []string{}
 	tags := params.ScriptOptions.SystemTags.Map()
 	for tag, flag := range tags {
+		systemTag, err := metrics.SystemTagString(tag)
+		if err != nil {
+			return nil, err
+		}
+
+		// The non-indexable system tags are neither a "resTag"
+		// nor an "ignoreTag". They aren't a "resTag" as they
+		// aren't added as a column in the CSV. Yet they also
+		// shouldn't be ignored as they are added to the
+		// "metadata" column
+		if metrics.NonIndexableSystemTags.Has(systemTag) {
+			continue
+		}
+
 		if flag {
 			resTags = append(resTags, tag)
 		} else {

output/csv/output_test.go

@@ -245,6 +245,7 @@ func TestRun(t *testing.T) {
 							"url":   "val2",
 							"error": "val3",
 							"tag4":  "val4",
+							"vu":    "1",
 						}),
 					},
 					Metadata: map[string]string{},
@@ -257,7 +258,7 @@ func TestRun(t *testing.T) {
 			timeFormat:     "",
 			outputContent: "metric_name,timestamp,metric_value,check,error,extra_tags,metadata\n" +
 				"my_metric,1562324643,1.000000,val1,val3,url=val2,\n" +
-				"my_metric,1562324644,1.000000,val1,val3,tag4=val4&url=val2,\n",
+				"my_metric,1562324644,1.000000,val1,val3,tag4=val4&url=val2&vu=1,\n",
 		},
 		{
 			samples: []metrics.SampleContainer{
@@ -350,7 +351,7 @@ func TestRun(t *testing.T) {
 				Environment:    env,
 				ConfigArgument: data.fileName,
 				ScriptOptions: lib.Options{
-					SystemTags: metrics.NewSystemTagSet(metrics.TagError | metrics.TagCheck),
+					SystemTags: metrics.NewSystemTagSet(metrics.TagError | metrics.TagCheck | metrics.TagVU),
 				},
 			})
 			require.NoError(t, err)