Support StatisticValues in cloudwatch output plugin (influxdata#4318)

plugins/outputs/cloudwatch/README.md

@@ -36,3 +36,12 @@ Examples include but are not limited to:
 ### namespace
 
 The namespace used for AWS CloudWatch metrics.
+
+### enable_statistic_values
+
+If you have a large amount of metrics, you should consider to send 
+statistic values instead of raw metrics. This would not only improve
+performance but also save AWS API cost. Use `basicstats` aggregator to 
+calculate those required statistic fields (count, min, max, and sum).
+[See Cloudwatch StatisticSet](https://docs.aws.amazon.com/sdk-for-go/api/service/cloudwatch/#StatisticSet).
+This plugin would try to parse those statistic fields and send to Cloudwatch.

plugins/outputs/cloudwatch/cloudwatch.go

@@ -27,6 +27,16 @@ type CloudWatch struct {
 
 	Namespace string `toml:"namespace"` // CloudWatch Metrics Namespace
 	svc       *cloudwatch.CloudWatch
+
+	EnableStatisticValues bool `toml:"enable_statistic_values"`
+}
+
+type statisticSet struct {
+	field string
+	max   float64
+	min   float64
+	sum   float64
+	count float64
 }
 
 var sampleConfig = `
@@ -50,6 +60,14 @@ var sampleConfig = `
 
   ## Namespace for the CloudWatch MetricDatums
   namespace = "InfluxData/Telegraf"
+
+  ## If you have a large amount of metrics, you should consider to send 
+  ## statistic values instead of raw metrics. This would not only improve
+  ## performance but also save AWS API cost. Use basicstats aggregator to
+  ## calculate required statistic fields (count, min, max, and sum) and 
+  ## enable this flag. This plugin would try to parse those fields and 
+  ## send statistic values to Cloudwatch.
+  # enable_statistic_values = false
 `
 
 func (c *CloudWatch) SampleConfig() string {
@@ -107,7 +125,7 @@ func (c *CloudWatch) Write(metrics []telegraf.Metric) error {
 // is equal to one MetricDatum. There is a limit on how many MetricDatums a
 // request can have so we process one Point at a time.
 func (c *CloudWatch) WriteSinglePoint(point telegraf.Metric) error {
-	datums := BuildMetricDatum(point)
+	datums := BuildMetricDatum(c.EnableStatisticValues, point)
 
 	const maxDatumsPerCall = 20 // PutMetricData only supports up to 20 data metrics per call
 
@@ -161,9 +179,28 @@ func PartitionDatums(size int, datums []*cloudwatch.MetricDatum) [][]*cloudwatch
 	return partitions
 }
 
+// Make a MetricDatum from telegraf.Metric. It would check if all required fields of
+// cloudwatch.StatisticSet are available. If so, it would build MetricDatum from statistic values.
+// Otherwise, it would make MetricDatum from each field in a Point.
+func BuildMetricDatum(buildStatistic bool, point telegraf.Metric) []*cloudwatch.MetricDatum {
+
+	// If not enable, just take all metrics as value datums.
+	if !buildStatistic {
+		return BuildValueMetricDatum(point)
+	}
+
+	// Try to parse statisticSet first, then build statistic/value datum accordingly.
+	set, ok := getStatisticSet(point)
+	if ok {
+		return BuildStatisticMetricDatum(point, set)
+	} else {
+		return BuildValueMetricDatum(point)
+	}
+}
+
 // Make a MetricDatum for each field in a Point. Only fields with values that can be
 // converted to float64 are supported. Non-supported fields are skipped.
-func BuildMetricDatum(point telegraf.Metric) []*cloudwatch.MetricDatum {
+func BuildValueMetricDatum(point telegraf.Metric) []*cloudwatch.MetricDatum {
 	datums := make([]*cloudwatch.MetricDatum, len(point.Fields()))
 	i := 0
 
@@ -227,6 +264,24 @@ func BuildMetricDatum(point telegraf.Metric) []*cloudwatch.MetricDatum {
 	return datums
 }
 
+// Make a MetricDatum with statistic values.
+func BuildStatisticMetricDatum(point telegraf.Metric, set *statisticSet) []*cloudwatch.MetricDatum {
+
+	data := &cloudwatch.MetricDatum{
+		MetricName: aws.String(strings.Join([]string{point.Name(), set.field}, "_")),
+		StatisticValues: &cloudwatch.StatisticSet{
+			Minimum:     aws.Float64(set.min),
+			Maximum:     aws.Float64(set.max),
+			Sum:         aws.Float64(set.sum),
+			SampleCount: aws.Float64(set.count),
+		},
+		Dimensions: BuildDimensions(point.Tags()),
+		Timestamp:  aws.Time(point.Time()),
+	}
+
+	return []*cloudwatch.MetricDatum{data}
+}
+
 // Make a list of Dimensions by using a Point's tags. CloudWatch supports up to
 // 10 dimensions per metric so we only keep up to the first 10 alphabetically.
 // This always includes the "host" tag if it exists.
@@ -270,6 +325,66 @@ func BuildDimensions(mTags map[string]string) []*cloudwatch.Dimension {
 	return dimensions
 }
 
+func getStatisticSet(point telegraf.Metric) (*statisticSet, bool) {
+
+	// cloudwatch.StatisticSet requires Max, Min, Count and Sum values.
+	// If this point has less than 4 fields, it's not possible to build
+	// StatisticSet from it.
+	if len(point.Fields()) < 4 {
+		return nil, false
+	}
+
+	// Try to find the max field. If we could find it, we will use its
+	// field name to find other required fields.
+	var set *statisticSet
+	for k, v := range point.Fields() {
+		if strings.HasSuffix(k, "_max") {
+			if fv, ok := convert(v); ok {
+				set = &statisticSet{
+					field: k[:len(k)-4],
+					max:   fv,
+				}
+				break
+			}
+		}
+	}
+	if set == nil {
+		return nil, false
+	}
+
+	// Check if we could find all required fields with the same field name
+	var ok bool
+	if set.min, ok = findField(point, set.field+"_min"); !ok {
+		return nil, false
+	}
+	if set.count, ok = findField(point, set.field+"_count"); !ok {
+		return nil, false
+	}
+	if set.sum, ok = findField(point, set.field+"_sum"); !ok {
+		return nil, false
+	}
+
+	return set, true
+}
+
+func convert(in interface{}) (float64, bool) {
+	switch v := in.(type) {
+	case float64:
+		return v, true
+	default:
+		return 0, false
+	}
+}
+
+func findField(point telegraf.Metric, field string) (float64, bool) {
+	if v, ok := point.GetField(field); ok {
+		if fv, ok := convert(v); ok {
+			return fv, true
+		}
+	}
+	return 0, false
+}
+
 func init() {
 	outputs.Add("cloudwatch", func() telegraf.Output {
 		return &CloudWatch{}

plugins/outputs/cloudwatch/cloudwatch_test.go

@@ -5,11 +5,13 @@ import (
 	"math"
 	"sort"
 	"testing"
+	"time"
 
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/service/cloudwatch"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/metric"
 	"github.com/influxdata/telegraf/testutil"
 
 	"github.com/stretchr/testify/assert"
@@ -72,13 +74,31 @@ func TestBuildMetricDatums(t *testing.T) {
 		testutil.TestMetric(float64(1.174272e+108)), // largest should be 1.174271e+108
 	}
 	for _, point := range validMetrics {
-		datums := BuildMetricDatum(point)
+		datums := BuildMetricDatum(false, point)
 		assert.Equal(1, len(datums), fmt.Sprintf("Valid point should create a Datum {value: %v}", point))
 	}
 	for _, point := range invalidMetrics {
-		datums := BuildMetricDatum(point)
+		datums := BuildMetricDatum(false, point)
 		assert.Equal(0, len(datums), fmt.Sprintf("Valid point should not create a Datum {value: %v}", point))
 	}
+
+	statisticMetric, _ := metric.New(
+		"test1",
+		map[string]string{"tag1": "value1"},
+		map[string]interface{}{"value_max": float64(10), "value_min": float64(0), "value_sum": float64(100), "value_count": float64(20)},
+		time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC),
+	)
+	datums := BuildMetricDatum(true, statisticMetric)
+	assert.Equal(1, len(datums), fmt.Sprintf("Valid point should create a Datum {value: %v}", statisticMetric))
+
+	multipleFieldsMetric, _ := metric.New(
+		"test1",
+		map[string]string{"tag1": "value1"},
+		map[string]interface{}{"valueA": float64(10), "valueB": float64(0), "valueC": float64(100), "valueD": float64(20)},
+		time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC),
+	)
+	datums = BuildMetricDatum(true, multipleFieldsMetric)
+	assert.Equal(4, len(datums), fmt.Sprintf("Each field should create a Datum {value: %v}", multipleFieldsMetric))
 }
 
 func TestPartitionDatums(t *testing.T) {