Format extract load balancer id from arn

Author: nmorsman

format/aws.go

@@ -11,13 +11,18 @@ import "regexp"
 //
 
 var arnEc2InstanceRe = regexp.MustCompile(`^arn:aws:ec2:.+/([^/]+)`)
+var arnLoadBalancerIdRe = regexp.MustCompile(`^arn:aws:elasticloadbalancing:[^:]+:\d+:loadbalancer/(.+)$`)
 var arnEcsTaskToClusterRe = regexp.MustCompile(`^(arn:aws:ecs:[^:]+:\d+):task/([^/]+)/.*`)
 var arnCloudFrontDistributionRe = regexp.MustCompile(`^arn:aws:cloudfront::\d+:distribution/([^/]+)`)
 
 func Ec2InstanceIdFromArn(arn string) string {
 	return arnEc2InstanceRe.ReplaceAllString(arn, "${1}")
 }
 
+func LoadBalancerIdFromArn(arn string) string {
+	return arnLoadBalancerIdRe.ReplaceAllString(arn, "${1}")
+}
+
 func EcsTaskArnToClusterArn(arn string) string {
 	return arnEcsTaskToClusterRe.ReplaceAllString(arn, "${1}:cluster/${2}")
 }

format/aws_test.go

@@ -17,6 +17,18 @@ func TestEc2InstanceIdFromArnErr(t *testing.T) {
 	assert.Equal(t, arn, result)
 }
 
+func TestLoadBalancerIdFromArn(t *testing.T) {
+	arn := "arn:aws:elasticloadbalancing:us-west-1:1234567890:loadbalancer/app/my-load-balancer/50dc6c495c0c9188"
+	result := LoadBalancerIdFromArn(arn)
+	assert.Equal(t, "app/my-load-balancer/50dc6c495c0c9188", result)
+}
+
+func TestLoadBalancerIdFromArnErr(t *testing.T) {
+	arn := "invalid-arn"
+	result := LoadBalancerIdFromArn(arn)
+	assert.Equal(t, arn, result)
+}
+
 func TestEcsTaskArnToClusterArn(t *testing.T) {
 	result := EcsTaskArnToClusterArn("arn:aws:ecs:us-west-1:1234567890:task/my-cluster/3f8fae2a-33ce-4c19-ba06-3f3009a7c33a")
 	assert.Equal(t, "arn:aws:ecs:us-west-1:1234567890:cluster/my-cluster", result)