Added CloudWatch metric constraint validation (#3183)

(cherry picked from commit ac1fa05672)

plugins/outputs/cloudwatch/cloudwatch.go

@@ -193,6 +193,25 @@ func BuildMetricDatum(point telegraf.Metric) []*cloudwatch.MetricDatum {
 			continue
 		}
 
+		// Do CloudWatch boundary checking
+		// Constraints at: http://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/API_MetricDatum.html
+		if math.IsNaN(value) {
+			datums = datums[:len(datums)-1]
+			continue
+		}
+		if math.IsInf(value, 0) {
+			datums = datums[:len(datums)-1]
+			continue
+		}
+		if value > 0 && value < float64(8.515920e-109) {
+			datums = datums[:len(datums)-1]
+			continue
+		}
+		if value > float64(1.174271e+108) {
+			datums = datums[:len(datums)-1]
+			continue
+		}
+
 		datums[i] = &cloudwatch.MetricDatum{
 			MetricName: aws.String(strings.Join([]string{point.Name(), k}, "_")),
 			Value:      aws.Float64(value),

plugins/outputs/cloudwatch/cloudwatch_test.go

@@ -1,6 +1,8 @@
 package cloudwatch
 
 import (
+	"fmt"
+	"math"
 	"sort"
 	"testing"
 
@@ -51,22 +53,32 @@ func TestBuildDimensions(t *testing.T) {
 func TestBuildMetricDatums(t *testing.T) {
 	assert := assert.New(t)
 
+	zero := 0.0
 	validMetrics := []telegraf.Metric{
 		testutil.TestMetric(1),
 		testutil.TestMetric(int32(1)),
 		testutil.TestMetric(int64(1)),
 		testutil.TestMetric(float64(1)),
+		testutil.TestMetric(float64(0)),
+		testutil.TestMetric(math.Copysign(zero, -1)), // the CW documentation does not call out -0 as rejected
+		testutil.TestMetric(float64(8.515920e-109)),
+		testutil.TestMetric(float64(1.174271e+108)), // largest should be 1.174271e+108
 		testutil.TestMetric(true),
 	}
-
+	invalidMetrics := []telegraf.Metric{
+		testutil.TestMetric("Foo"),
+		testutil.TestMetric(math.Log(-1.0)),
+		testutil.TestMetric(float64(8.515919e-109)), // smallest should be 8.515920e-109
+		testutil.TestMetric(float64(1.174272e+108)), // largest should be 1.174271e+108
+	}
 	for _, point := range validMetrics {
 		datums := BuildMetricDatum(point)
-		assert.Equal(1, len(datums), "Valid type should create a Datum")
+		assert.Equal(1, len(datums), fmt.Sprintf("Valid point should create a Datum {value: %v}", point))
+	}
+	for _, point := range invalidMetrics {
+		datums := BuildMetricDatum(point)
+		assert.Equal(0, len(datums), fmt.Sprintf("Valid point should not create a Datum {value: %v}", point))
 	}
-
-	nonValidPoint := testutil.TestMetric("Foo")
-
-	assert.Equal(0, len(BuildMetricDatum(nonValidPoint)), "Invalid type should not create a Datum")
 }
 
 func TestPartitionDatums(t *testing.T) {
@@ -78,10 +90,13 @@ func TestPartitionDatums(t *testing.T) {
 		Value:      aws.Float64(1),
 	}
 
+	zeroDatum := []*cloudwatch.MetricDatum{}
 	oneDatum := []*cloudwatch.MetricDatum{&testDatum}
 	twoDatum := []*cloudwatch.MetricDatum{&testDatum, &testDatum}
 	threeDatum := []*cloudwatch.MetricDatum{&testDatum, &testDatum, &testDatum}
 
+	assert.Equal([][]*cloudwatch.MetricDatum{}, PartitionDatums(2, zeroDatum))
+	assert.Equal([][]*cloudwatch.MetricDatum{oneDatum}, PartitionDatums(2, oneDatum))
 	assert.Equal([][]*cloudwatch.MetricDatum{oneDatum}, PartitionDatums(2, oneDatum))
 	assert.Equal([][]*cloudwatch.MetricDatum{twoDatum}, PartitionDatums(2, twoDatum))
 	assert.Equal([][]*cloudwatch.MetricDatum{twoDatum, oneDatum}, PartitionDatums(2, threeDatum))