Add limit error for prefix

Author: adamginna-akamai

cloud/linode/cloud.go

@@ -72,6 +72,7 @@ type linodeCloud struct {
 var (
 	instanceCache     *instances
 	ipHolderCharLimit int = 23
+	LoadBalancerPrefixCharLimit int = 20
 )
 
 func init() {
@@ -194,6 +195,12 @@ func newCloud() (cloudprovider.Interface, error) {
 		return nil, fmt.Errorf("%s", msg)
 	}
 
+	if len(Options.LoadBalancerPrefix) > LoadBalancerPrefixCharLimit { 
+		msg := fmt.Sprintf("load-balancer-prefix must be %d characters or less: %s is %d characters\n", LoadBalancerPrefixCharLimit, Options.LoadBalancerPrefix, len(Options.LoadBalancerPrefix))
+		klog.Error(msg)
+		return nil, fmt.Errorf("%s", msg)
+	}
+
 	// create struct that satisfies cloudprovider.Interface
 	lcloud := &linodeCloud{
 		client:                   linodeClient,

cloud/linode/cloud_test.go

@@ -126,6 +126,16 @@ func TestNewCloud(t *testing.T) {
 		_, err := newCloud()
 		assert.Error(t, err, "expected error if ipholdersuffix is longer than 23 chars")
 	})
+
+	t.Run("should fail if load-balancer-prefix is longer than 20 chars", func(t *testing.T) {
+		prefix := Options.LoadBalancerPrefix
+		Options.LoadBalancerPrefix = strings.Repeat("a", 21)
+		defer func() {
+			Options.LoadBalancerPrefix = prefix
+		}()
+		_, err := newCloud()
+		assert.Error(t, err, "expected error if load-balancer-prefix is longer than 20 chars")
+	})
 }
 
 func Test_linodeCloud_LoadBalancer(t *testing.T) {

main.go

@@ -98,7 +98,7 @@ func main() {
 	command.Flags().IntVar(&linode.Options.NodeBalancerBackendIPv4SubnetID, "nodebalancer-backend-ipv4-subnet-id", 0, "ipv4 subnet id to use for NodeBalancer backends")
 	command.Flags().StringVar(&linode.Options.NodeBalancerBackendIPv4SubnetName, "nodebalancer-backend-ipv4-subnet-name", "", "ipv4 subnet name to use for NodeBalancer backends")
 	command.Flags().BoolVar(&linode.Options.DisableNodeBalancerVPCBackends, "disable-nodebalancer-vpc-backends", false, "disables nodebalancer backends in VPCs (when enabled, nodebalancers will only have private IPs as backends for backward compatibility)")
-	command.Flags().StringVar(&linode.Options.LoadBalancerPrefix, "load-balancer-prefix", "ccm-", "Name prefix for LoadBalancers. (Max 20 char.)")
+	command.Flags().StringVar(&linode.Options.LoadBalancerPrefix, "load-balancer-prefix", "ccm-", "Name prefix for LoadBalancers. (max. 20 char.)")
 
 	// Set static flags
 	command.Flags().VisitAll(func(fl *pflag.Flag) {