chore: GCPCluster webhook: Throw error if MTU in the new incoming spec is more than 8896 bytes or lesser than 1300 bytes

Author: tasdikrahman-newrelic

api/v1beta1/gcpcluster_webhook.go

@@ -92,6 +92,20 @@ func (c *GCPCluster) ValidateUpdate(oldRaw runtime.Object) (admission.Warnings,
 		)
 	}
 
+	if c.Spec.Network.Mtu < int64(1300) {
+		allErrs = append(allErrs,
+			field.Invalid(field.NewPath("spec", "Network", "Mtu"),
+				c.Spec.Network.Mtu, "field cannot be lesser than 1300"),
+		)
+	}
+
+	if c.Spec.Network.Mtu > int64(8896) {
+		allErrs = append(allErrs,
+			field.Invalid(field.NewPath("spec", "Network", "Mtu"),
+				c.Spec.Network.Mtu, "field cannot be greater than 8896"),
+		)
+	}
+
 	if len(allErrs) == 0 {
 		return nil, nil
 	}

api/v1beta1/gcpcluster_webhook_test.go

@@ -0,0 +1,102 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1beta1
+
+import (
+	"testing"
+
+	. "github.com/onsi/gomega"
+)
+
+func TestGCPCluster_ValidateUpdate(t *testing.T) {
+	g := NewWithT(t)
+
+	tests := []struct {
+		name       string
+		newCluster *GCPCluster
+		oldCluster *GCPCluster
+		wantErr    bool
+	}{
+		{
+			name: "GCPCluster with MTU field is within the limits of more than 1300 and less than 8896",
+			newCluster: &GCPCluster{
+				Spec: GCPClusterSpec{
+					Network: NetworkSpec{
+						Mtu: int64(1500),
+					},
+				},
+			},
+			oldCluster: &GCPCluster{
+				Spec: GCPClusterSpec{
+					Network: NetworkSpec{
+						Mtu: int64(1400),
+					},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "GCPCluster with MTU field more than 8896",
+			newCluster: &GCPCluster{
+				Spec: GCPClusterSpec{
+					Network: NetworkSpec{
+						Mtu: int64(10000),
+					},
+				},
+			},
+			oldCluster: &GCPCluster{
+				Spec: GCPClusterSpec{
+					Network: NetworkSpec{
+						Mtu: int64(1500),
+					},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "GCPCluster with MTU field less than 8896",
+			newCluster: &GCPCluster{
+				Spec: GCPClusterSpec{
+					Network: NetworkSpec{
+						Mtu: int64(1250),
+					},
+				},
+			},
+			oldCluster: &GCPCluster{
+				Spec: GCPClusterSpec{
+					Network: NetworkSpec{
+						Mtu: int64(1500),
+					},
+				},
+			},
+			wantErr: true,
+		},
+	}
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+			warn, err := test.newCluster.ValidateUpdate(test.oldCluster)
+			if test.wantErr {
+				g.Expect(err).To(HaveOccurred())
+			} else {
+				g.Expect(err).NotTo(HaveOccurred())
+			}
+			g.Expect(warn).To(BeNil())
+		})
+	}
+}