Adding the ARN as an output of the DB Subnet Group

builtin/providers/aws/resource_aws_db_subnet_group.go

@@ -23,6 +23,11 @@ func resourceAwsDbSubnetGroup() *schema.Resource {
 		Delete: resourceAwsDbSubnetGroupDelete,
 
 		Schema: map[string]*schema.Schema{
+			"arn": &schema.Schema{
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+
 			"name": &schema.Schema{
 				Type:     schema.TypeString,
 				ForceNew: true,
@@ -142,6 +147,7 @@ func resourceAwsDbSubnetGroupRead(d *schema.ResourceData, meta interface{}) erro
 	if err != nil {
 		log.Printf("[DEBUG] Error building ARN for DB Subnet Group, not setting Tags for group %s", *subnetGroup.DBSubnetGroupName)
 	} else {
+		d.Set("arn", arn)
 		resp, err := conn.ListTagsForResource(&rds.ListTagsForResourceInput{
 			ResourceName: aws.String(arn),
 		})

website/source/docs/providers/aws/r/db_subnet_group.html.markdown

@@ -37,4 +37,5 @@ The following arguments are supported:
 The following attributes are exported:
 
 * `id` - The db subnet group name.
+* `arn` - The ARN of the db subnet group.