Fix parse of unix timestamp with more than ns precision (#5826)

plugins/parsers/csv/parser.go

@@ -225,29 +225,25 @@ outer:
 // to the format.
 func parseTimestamp(timeFunc func() time.Time, recordFields map[string]interface{},
 	timestampColumn, timestampFormat string,
-) (metricTime time.Time, err error) {
-	metricTime = timeFunc()
-
+) (time.Time, error) {
 	if timestampColumn != "" {
 		if recordFields[timestampColumn] == nil {
-			err = fmt.Errorf("timestamp column: %v could not be found", timestampColumn)
-			return
+			return time.Time{}, fmt.Errorf("timestamp column: %v could not be found", timestampColumn)
 		}
 
-		tStr := fmt.Sprintf("%v", recordFields[timestampColumn])
-
 		switch timestampFormat {
 		case "":
-			err = fmt.Errorf("timestamp format must be specified")
-			return
+			return time.Time{}, fmt.Errorf("timestamp format must be specified")
 		default:
-			metricTime, err = internal.ParseTimestamp(tStr, timestampFormat)
+			metricTime, err := internal.ParseTimestamp(recordFields[timestampColumn], timestampFormat)
 			if err != nil {
-				return
+				return time.Time{}, err
 			}
+			return metricTime, err
 		}
 	}
-	return
+
+	return timeFunc(), nil
 }
 
 // SetDefaultTags set the DefaultTags

plugins/parsers/csv/parser_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/metric"
 	"github.com/influxdata/telegraf/testutil"
 	"github.com/stretchr/testify/require"
@@ -322,3 +323,30 @@ func TestParseStream(t *testing.T) {
 			DefaultTime(),
 		), metric)
 }
+
+func TestTimestampUnixFloatPrecision(t *testing.T) {
+	p := Parser{
+		MetricName:      "csv",
+		ColumnNames:     []string{"time", "value"},
+		TimestampColumn: "time",
+		TimestampFormat: "unix",
+		TimeFunc:        DefaultTime,
+	}
+	data := `1551129661.95456123352050781250,42`
+
+	expected := []telegraf.Metric{
+		testutil.MustMetric(
+			"csv",
+			map[string]string{},
+			map[string]interface{}{
+				"value": 42,
+				"time":  1551129661.954561233,
+			},
+			time.Unix(1551129661, 954561233),
+		),
+	}
+
+	metrics, err := p.Parse([]byte(data))
+	require.NoError(t, err)
+	testutil.RequireMetricsEqual(t, expected, metrics)
+}