fix(outputs.stackdriver): Group batches by timestamp (#12994)

plugins/outputs/stackdriver/stackdriver.go

@@ -131,11 +131,38 @@ func (tsb timeSeriesBuckets) Add(m telegraf.Metric, f *telegraf.Field, ts *monit
 	tsb[k] = s
 }
 
-// Write the metrics to Google Cloud Stackdriver.
+// Split metrics up by timestamp and send to Google Cloud Stackdriver
 func (s *Stackdriver) Write(metrics []telegraf.Metric) error {
+	metricBatch := make(map[int64][]telegraf.Metric)
+	timestamps := []int64{}
+	for _, metric := range sorted(metrics) {
+		timestamp := metric.Time().UnixNano()
+		if existingSlice, ok := metricBatch[timestamp]; ok {
+			metricBatch[timestamp] = append(existingSlice, metric)
+		} else {
+			metricBatch[timestamp] = []telegraf.Metric{metric}
+			timestamps = append(timestamps, timestamp)
+		}
+	}
+
+	// sort the timestamps we collected
+	sort.Slice(timestamps, func(i, j int) bool { return timestamps[i] < timestamps[j] })
+
+	s.Log.Debugf("received %d metrics\n", len(metrics))
+	s.Log.Debugf("split into %d groups by timestamp\n", len(metricBatch))
+	for _, timestamp := range timestamps {
+		if err := s.sendBatch(metricBatch[timestamp]); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// Write the metrics to Google Cloud Stackdriver.
+func (s *Stackdriver) sendBatch(batch []telegraf.Metric) error {
 	ctx := context.Background()
 
-	batch := sorted(metrics)
 	buckets := make(timeSeriesBuckets)
 	for _, m := range batch {
 		for _, f := range m.FieldList() {

plugins/outputs/stackdriver/stackdriver_test.go

@@ -314,14 +314,16 @@ func TestWriteBatchable(t *testing.T) {
 	err = s.Write(metrics)
 	require.NoError(t, err)
 
-	require.Len(t, mockMetric.reqs, 2)
+	require.Len(t, mockMetric.reqs, 5)
+
+	// Request 1 with two time series
 	request := mockMetric.reqs[0].(*monitoringpb.CreateTimeSeriesRequest)
-	require.Len(t, request.TimeSeries, 6)
+	require.Len(t, request.TimeSeries, 2)
 	ts := request.TimeSeries[0]
 	require.Len(t, ts.Points, 1)
 	require.Equal(t, ts.Points[0].Interval, &monitoringpb.TimeInterval{
 		EndTime: &timestamppb.Timestamp{
-			Seconds: 3,
+			Seconds: 1,
 		},
 	})
 	require.Equal(t, ts.Points[0].Value, &monitoringpb.TypedValue{
@@ -343,31 +345,47 @@ func TestWriteBatchable(t *testing.T) {
 		},
 	})
 
-	ts = request.TimeSeries[2]
+	// Request 2 with 1 time series
+	request = mockMetric.reqs[1].(*monitoringpb.CreateTimeSeriesRequest)
+	require.Len(t, request.TimeSeries, 1)
 	require.Len(t, ts.Points, 1)
-	require.Equal(t, ts.Points[0].Interval, &monitoringpb.TimeInterval{
+	require.Equal(t, &monitoringpb.TimeInterval{
+		EndTime: &timestamppb.Timestamp{
+			Seconds: 2,
+		},
+	}, request.TimeSeries[0].Points[0].Interval)
+
+	// Request 3 with 1 time series with 1 point
+	request = mockMetric.reqs[2].(*monitoringpb.CreateTimeSeriesRequest)
+	require.Len(t, request.TimeSeries, 3)
+	require.Len(t, request.TimeSeries[0].Points, 1)
+	require.Len(t, request.TimeSeries[1].Points, 1)
+	require.Len(t, request.TimeSeries[2].Points, 1)
+	require.Equal(t, &monitoringpb.TimeInterval{
 		EndTime: &timestamppb.Timestamp{
 			Seconds: 3,
 		},
-	})
-	require.Equal(t, ts.Points[0].Value, &monitoringpb.TypedValue{
-		Value: &monitoringpb.TypedValue_Int64Value{
-			Int64Value: int64(43),
-		},
-	})
+	}, request.TimeSeries[0].Points[0].Interval)
 
-	ts = request.TimeSeries[4]
-	require.Len(t, ts.Points, 1)
-	require.Equal(t, ts.Points[0].Interval, &monitoringpb.TimeInterval{
+	// Request 4 with 1 time series with 1 point
+	request = mockMetric.reqs[3].(*monitoringpb.CreateTimeSeriesRequest)
+	require.Len(t, request.TimeSeries, 1)
+	require.Len(t, request.TimeSeries[0].Points, 1)
+	require.Equal(t, &monitoringpb.TimeInterval{
+		EndTime: &timestamppb.Timestamp{
+			Seconds: 4,
+		},
+	}, request.TimeSeries[0].Points[0].Interval)
+
+	// Request 5 with 1 time series with 1 point
+	request = mockMetric.reqs[4].(*monitoringpb.CreateTimeSeriesRequest)
+	require.Len(t, request.TimeSeries, 1)
+	require.Len(t, request.TimeSeries[0].Points, 1)
+	require.Equal(t, &monitoringpb.TimeInterval{
 		EndTime: &timestamppb.Timestamp{
 			Seconds: 5,
 		},
-	})
-	require.Equal(t, ts.Points[0].Value, &monitoringpb.TypedValue{
-		Value: &monitoringpb.TypedValue_Int64Value{
-			Int64Value: int64(43),
-		},
-	})
+	}, request.TimeSeries[0].Points[0].Interval)
 }
 
 func TestWriteIgnoredErrors(t *testing.T) {