[MetricBeat] set tags correctly if the dimension value is ARN

CHANGELOG.next.asciidoc

@@ -260,6 +260,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Fix incorrect usage of hints builder when exposed port is a substring of the hint {pull}19052[19052]
 - Remove dedot for tag values in aws module. {issue}19112[19112] {pull}19221[19221]
 - Stop counterCache only when already started {pull}19103[19103]
+- Set tags correctly if the dimension value is ARN {issue}19111[19111] {pull}19433[19433]
 - Fix bug incorrect parsing of float numbers as integers in Couchbase module {issue}18949[18949] {pull}19055[19055]
 
 *Packetbeat*

x-pack/metricbeat/module/aws/cloudwatch/cloudwatch.go

@@ -615,6 +615,13 @@ func insertTags(events map[string]mb.Event, identifier string, resourceTagMap ma
 	subIdentifiers := strings.Split(identifier, dimensionSeparator)
 	for _, v := range subIdentifiers {
 		tags := resourceTagMap[v]
+		// some metric dimension values are arn format, eg: AWS/DDOS namespace metric
+		if len(tags) == 0 && strings.HasPrefix(v, "arn:") {
+			resourceID, err := aws.FindIdentifierFromARN(v)
+			if err == nil {
+				tags = resourceTagMap[resourceID]
+			}
+		}
 		if len(tags) != 0 {
 			// By default, replace dot "." using underscore "_" for tag keys.
 			// Note: tag values are not dedotted.

x-pack/metricbeat/module/aws/cloudwatch/cloudwatch_test.go

@@ -1407,10 +1407,14 @@ func TestInsertTags(t *testing.T) {
 	tagValue1 := "engineering"
 	tagKey2 := "owner"
 	tagValue2 := "foo"
+	identifierContainsArn := "arn:aws:ec2:ap-northeast-1:111111111111:eip-allocation/eipalloc-0123456789abcdef,SYNFlood"
+	tagKey3 := "env"
+	tagValue3 := "dev"
 
 	events := map[string]mb.Event{}
 	events[identifier1] = aws.InitEvent(regionName, accountName, accountID)
 	events[identifier2] = aws.InitEvent(regionName, accountName, accountID)
+	events[identifierContainsArn] = aws.InitEvent(regionName, accountName, accountID)
 
 	resourceTagMap := map[string][]resourcegroupstaggingapi.Tag{}
 	resourceTagMap["test-s3-1"] = []resourcegroupstaggingapi.Tag{
@@ -1425,6 +1429,12 @@ func TestInsertTags(t *testing.T) {
 			Value: awssdk.String(tagValue2),
 		},
 	}
+	resourceTagMap["eipalloc-0123456789abcdef"] = []resourcegroupstaggingapi.Tag{
+		{
+			Key:   awssdk.String(tagKey3),
+			Value: awssdk.String(tagValue3),
+		},
+	}
 
 	cases := []struct {
 		title            string
@@ -1444,6 +1454,12 @@ func TestInsertTags(t *testing.T) {
 			"aws.tags.owner",
 			tagValue2,
 		},
+		{
+			"test identifier with arn value",
+			identifierContainsArn,
+			"aws.tags.env",
+			tagValue3,
+		},
 	}
 
 	for _, c := range cases {

x-pack/metricbeat/module/aws/utils.go

@@ -188,9 +188,9 @@ func GetResourcesTags(svc resourcegroupstaggingapiiface.ClientAPI, resourceTypeF
 		}
 
 		for _, resourceTag := range output.ResourceTagMappingList {
-			identifier, err := findIdentifierFromARN(*resourceTag.ResourceARN)
+			identifier, err := FindIdentifierFromARN(*resourceTag.ResourceARN)
 			if err != nil {
-				err = errors.Wrap(err, "error findIdentifierFromARN")
+				err = errors.Wrap(err, "error FindIdentifierFromARN")
 				return nil, err
 			}
 			resourceTagMap[identifier] = resourceTag.Tags
@@ -199,7 +199,7 @@ func GetResourcesTags(svc resourcegroupstaggingapiiface.ClientAPI, resourceTypeF
 	return resourceTagMap, nil
 }
 
-func findIdentifierFromARN(resourceARN string) (string, error) {
+func FindIdentifierFromARN(resourceARN string) (string, error) {
 	arnParsed, err := arn.Parse(resourceARN)
 	if err != nil {
 		err = errors.Wrap(err, "error Parse arn")

x-pack/metricbeat/module/aws/utils_test.go

@@ -377,7 +377,7 @@ func TestFindIdentifierFromARN(t *testing.T) {
 	}
 
 	for _, c := range cases {
-		identifier, err := findIdentifierFromARN(c.resourceARN)
+		identifier, err := FindIdentifierFromARN(c.resourceARN)
 		assert.NoError(t, err)
 		assert.Equal(t, c.expectedIdentifier, identifier)
 	}