From 2c9e60a8428468eec8e011392fa6d2b75a8cbb36 Mon Sep 17 00:00:00 2001
From: Will Hegedus <whegedus@linode.com>
Date: Wed, 8 Mar 2023 14:50:35 -0500
Subject: [PATCH 1/2] feat: truncate long labels in nodebalancers

Nodebalancer backends can have a max label length of 32 chars.

If a k8s node's name is longer than 32 chars, creating a nodebalancer fails.

Example error:
E0307 22:31:47.275176       1 controller.go:307] error processing service traefik/traefik (will retry): failed to ensure load balancer: [400] [configs[0].nodes[0].label] Length must be 3-32 characters; [configs[0].nodes[1].label] Length must be 3-32 characters; [configs[0].nodes[2].label] Length must be 3-32 characters;
---
 cloud/linode/loadbalancers.go | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/cloud/linode/loadbalancers.go b/cloud/linode/loadbalancers.go
index 95da8fa7..f7107946 100644
--- a/cloud/linode/loadbalancers.go
+++ b/cloud/linode/loadbalancers.go
@@ -644,12 +644,20 @@ func (l *loadbalancers) buildLoadBalancerRequest(ctx context.Context, clusterNam
 	return l.createNodeBalancer(ctx, clusterName, service, configs)
 }
 
+func trimString(s string, maxLen int) string {
+	if len(s) > maxLen {
+		return s[:maxLen]
+	}
+	return s
+}
+
 func (l *loadbalancers) buildNodeBalancerNodeCreateOptions(node *v1.Node, nodePort int32) linodego.NodeBalancerNodeCreateOptions {
 	return linodego.NodeBalancerNodeCreateOptions{
 		Address: fmt.Sprintf("%v:%v", getNodePrivateIP(node), nodePort),
-		Label:   node.Name,
-		Mode:    "accept",
-		Weight:  100,
+		// NodeBalancer backends must be 3-32 chars in length
+		Label:  trimString(node.Name, 32),
+		Mode:   "accept",
+		Weight: 100,
 	}
 }
 

From 7d957dce6887ae3e66321ff3b8d03ad21bb97e09 Mon Sep 17 00:00:00 2001
From: Will Hegedus <whegedus@linode.com>
Date: Tue, 28 Nov 2023 13:47:31 -0500
Subject: [PATCH 2/2] feat: pad nodebalancer backend names

Nodebalancers must have a name that is 3-32 characters in length.
This adds support to pad the node name if it's too short,
since in Kubernetes it's valid to have node names of only
1 or 2 characters.
---
 cloud/linode/loadbalancers.go      | 10 +++++--
 cloud/linode/loadbalancers_test.go | 42 ++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/cloud/linode/loadbalancers.go b/cloud/linode/loadbalancers.go
index f7107946..7cd1a0c5 100644
--- a/cloud/linode/loadbalancers.go
+++ b/cloud/linode/loadbalancers.go
@@ -644,9 +644,14 @@ func (l *loadbalancers) buildLoadBalancerRequest(ctx context.Context, clusterNam
 	return l.createNodeBalancer(ctx, clusterName, service, configs)
 }
 
-func trimString(s string, maxLen int) string {
+func coerceString(s string, minLen, maxLen int, padding string) string {
+	if len(padding) == 0 {
+		padding = "x"
+	}
 	if len(s) > maxLen {
 		return s[:maxLen]
+	} else if len(s) < minLen {
+		return coerceString(fmt.Sprintf("%s%s", padding, s), minLen, maxLen, padding)
 	}
 	return s
 }
@@ -655,7 +660,8 @@ func (l *loadbalancers) buildNodeBalancerNodeCreateOptions(node *v1.Node, nodePo
 	return linodego.NodeBalancerNodeCreateOptions{
 		Address: fmt.Sprintf("%v:%v", getNodePrivateIP(node), nodePort),
 		// NodeBalancer backends must be 3-32 chars in length
-		Label:  trimString(node.Name, 32),
+		// If < 3 chars, pad node name with "node-" prefix
+		Label:  coerceString(node.Name, 3, 32, "node-"),
 		Mode:   "accept",
 		Weight: 100,
 	}
diff --git a/cloud/linode/loadbalancers_test.go b/cloud/linode/loadbalancers_test.go
index 63afdcc7..489a2e7d 100644
--- a/cloud/linode/loadbalancers_test.go
+++ b/cloud/linode/loadbalancers_test.go
@@ -2114,3 +2114,45 @@ func addTLSSecret(t *testing.T, kubeClient kubernetes.Interface) {
 		t.Fatalf("failed to add TLS secret: %s\n", err)
 	}
 }
+
+func Test_LoadbalNodeNameCoercion(t *testing.T) {
+	type testCase struct {
+		nodeName       string
+		padding        string
+		expectedOutput string
+	}
+	testCases := []testCase{
+		{
+			nodeName:       "n",
+			padding:        "z",
+			expectedOutput: "zzn",
+		},
+		{
+			nodeName:       "n",
+			padding:        "node-",
+			expectedOutput: "node-n",
+		},
+		{
+			nodeName:       "n",
+			padding:        "",
+			expectedOutput: "xxn",
+		},
+		{
+			nodeName:       "infra-logging-controlplane-3-atl1-us-prod",
+			padding:        "node-",
+			expectedOutput: "infra-logging-controlplane-3-atl",
+		},
+		{
+			nodeName:       "node1",
+			padding:        "node-",
+			expectedOutput: "node1",
+		},
+	}
+
+	for _, tc := range testCases {
+		if out := coerceString(tc.nodeName, 3, 32, tc.padding); out != tc.expectedOutput {
+			t.Fatalf("Expected loadbal backend name to be %s (got: %s)", tc.expectedOutput, out)
+		}
+	}
+
+}