Export LastValueData to Prometheus and Stackdriver

exporter/prometheus/prometheus.go

@@ -239,6 +239,8 @@ func (c *collector) toMetric(desc *prometheus.Desc, v *view.View, row *view.Row)
 		return prometheus.NewConstHistogram(desc, uint64(data.Count), data.Sum(), points, tagValues(row.Tags)...)
 	case *view.SumData:
 		return prometheus.NewConstMetric(desc, prometheus.UntypedValue, float64(*data), tagValues(row.Tags)...)
+	case *view.LastValueData:
+		return prometheus.NewConstMetric(desc, prometheus.UntypedValue, data.Value, tagValues(row.Tags)...)
 	default:
 		return nil, fmt.Errorf("aggregation %T is not yet supported", v.Aggregation)
 	}

exporter/stackdriver/stats.go

@@ -263,6 +263,8 @@ func (e *statsExporter) createMeasure(ctx context.Context, vd *view.Data) error
 		}
 	case view.AggTypeDistribution:
 		valueType = metricpb.MetricDescriptor_DISTRIBUTION
+	case view.AggTypeLastValue:
+		valueType = metricpb.MetricDescriptor_DOUBLE
 	default:
 		return fmt.Errorf("unsupported aggregation type: %s", agg.Type.String())
 	}
@@ -348,6 +350,10 @@ func newTypedValue(vd *view.View, r *view.Row) *monitoringpb.TypedValue {
 				BucketCounts: v.CountPerBucket,
 			},
 		}}
+	case *view.LastValueData:
+		return &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DoubleValue{
+			DoubleValue: v.Value,
+		}}
 	}
 	return nil
 }

exporter/stackdriver/stats_test.go

@@ -97,6 +97,8 @@ func TestExporter_makeReq(t *testing.T) {
 	count2 := view.CountData(16)
 	sum1 := view.SumData(5.5)
 	sum2 := view.SumData(-11.1)
+	last1 := view.LastValueData{Value: 100}
+	last2 := view.LastValueData{Value: 200}
 	taskValue := getTaskValue()
 
 	tests := []struct {
@@ -241,6 +243,74 @@ func TestExporter_makeReq(t *testing.T) {
 				},
 			}},
 		},
+		{
+			name:   "last value agg",
+			projID: "proj-id",
+			vd:     newTestViewData(v, start, end, &last1, &last2),
+			want: []*monitoringpb.CreateTimeSeriesRequest{{
+				Name: monitoring.MetricProjectPath("proj-id"),
+				TimeSeries: []*monitoringpb.TimeSeries{
+					{
+						Metric: &metricpb.Metric{
+							Type: "custom.googleapis.com/opencensus/testview",
+							Labels: map[string]string{
+								"test_key":        "test-value-1",
+								opencensusTaskKey: taskValue,
+							},
+						},
+						Resource: &monitoredrespb.MonitoredResource{
+							Type: "global",
+						},
+						Points: []*monitoringpb.Point{
+							{
+								Interval: &monitoringpb.TimeInterval{
+									StartTime: &timestamp.Timestamp{
+										Seconds: start.Unix(),
+										Nanos:   int32(start.Nanosecond()),
+									},
+									EndTime: &timestamp.Timestamp{
+										Seconds: end.Unix(),
+										Nanos:   int32(end.Nanosecond()),
+									},
+								},
+								Value: &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DoubleValue{
+									DoubleValue: 100,
+								}},
+							},
+						},
+					},
+					{
+						Metric: &metricpb.Metric{
+							Type: "custom.googleapis.com/opencensus/testview",
+							Labels: map[string]string{
+								"test_key":        "test-value-2",
+								opencensusTaskKey: taskValue,
+							},
+						},
+						Resource: &monitoredrespb.MonitoredResource{
+							Type: "global",
+						},
+						Points: []*monitoringpb.Point{
+							{
+								Interval: &monitoringpb.TimeInterval{
+									StartTime: &timestamp.Timestamp{
+										Seconds: start.Unix(),
+										Nanos:   int32(start.Nanosecond()),
+									},
+									EndTime: &timestamp.Timestamp{
+										Seconds: end.Unix(),
+										Nanos:   int32(end.Nanosecond()),
+									},
+								},
+								Value: &monitoringpb.TypedValue{Value: &monitoringpb.TypedValue_DoubleValue{
+									DoubleValue: 200,
+								}},
+							},
+						},
+					},
+				},
+			}},
+		},
 		{
 			name:   "dist agg + time window",
 			projID: "proj-id",