Implemented isDefault behavior of storage class

examples/arango-local-storage.yaml

@@ -5,5 +5,6 @@ metadata:
 spec:
   storageClass:
     name: my-local-ssd
+    isDefault: true
   localPath:
   - /var/lib/arango-storage

pkg/storage/storage_class.go

@@ -38,6 +38,7 @@ var (
 // ensureStorageClass creates a storage class for the given local storage.
 // If such a class already exists, the create is ignored.
 func (l *LocalStorage) ensureStorageClass(apiObject *api.ArangoLocalStorage) error {
+	log := l.deps.Log
 	spec := apiObject.Spec.StorageClass
 	bindingMode := v1.VolumeBindingWaitForFirstConsumer
 	reclaimPolicy := corev1.PersistentVolumeReclaimRetain
@@ -49,10 +50,60 @@ func (l *LocalStorage) ensureStorageClass(apiObject *api.ArangoLocalStorage) err
 		VolumeBindingMode: &bindingMode,
 		Provisioner:       storageClassProvisioner,
 	}
-	if _, err := l.deps.KubeCli.StorageV1().StorageClasses().Create(sc); !k8sutil.IsAlreadyExists(err) && err != nil {
+	// Note: We do not attach the StorageClass to the apiObject (OwnerRef) because many
+	// ArangoLocalStorage resource may use the same StorageClass.
+	cli := l.deps.KubeCli.StorageV1()
+	if _, err := cli.StorageClasses().Create(sc); k8sutil.IsAlreadyExists(err) {
+		log.Debug().
+			Str("storageclass", sc.GetName()).
+			Msg("StorageClass already exists")
+	} else if err != nil {
+		log.Debug().Err(err).
+			Str("storageclass", sc.GetName()).
+			Msg("Failed to create StorageClass")
 		return maskAny(err)
+	} else {
+		log.Debug().
+			Str("storageclass", sc.GetName()).
+			Msg("StorageClass created")
+	}
+
+	if apiObject.Spec.StorageClass.IsDefault {
+		// UnMark current default (if any)
+		list, err := cli.StorageClasses().List(metav1.ListOptions{})
+		if err != nil {
+			log.Debug().Err(err).Msg("Listing StorageClasses failed")
+			return maskAny(err)
+		}
+		for _, scX := range list.Items {
+			if !k8sutil.StorageClassIsDefault(&scX) || scX.GetName() == sc.GetName() {
+				continue
+			}
+			// Mark storage class as non-default
+			if err := k8sutil.PatchStorageClassIsDefault(cli, scX.GetName(), false); err != nil {
+				log.Debug().
+					Err(err).
+					Str("storageclass", scX.GetName()).
+					Msg("Failed to mark StorageClass as not-default")
+				return maskAny(err)
+			}
+			log.Debug().
+				Str("storageclass", scX.GetName()).
+				Msg("Marked StorageClass as not-default")
+		}
+
+		// Mark StorageClass default
+		if err := k8sutil.PatchStorageClassIsDefault(cli, sc.GetName(), true); err != nil {
+			log.Debug().
+				Err(err).
+				Str("storageclass", sc.GetName()).
+				Msg("Failed to mark StorageClass as default")
+			return maskAny(err)
+		}
+		log.Debug().
+			Str("storageclass", sc.GetName()).
+			Msg("Marked StorageClass as default")
 	}
-	// TODO make default (if needed)
 
 	return nil
 }

pkg/util/k8sutil/storageclass.go

@@ -0,0 +1,59 @@
+//
+// DISCLAIMER
+//
+// Copyright 2018 ArangoDB GmbH, Cologne, Germany
+//
+// 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.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+// Author Ewout Prangsma
+//
+
+package k8sutil
+
+import (
+	"fmt"
+	"strconv"
+
+	"k8s.io/api/storage/v1"
+	"k8s.io/apimachinery/pkg/types"
+	storagev1 "k8s.io/client-go/kubernetes/typed/storage/v1"
+)
+
+const (
+	annStorageClassIsDefault = "storageclass.kubernetes.io/is-default-class"
+)
+
+// StorageClassIsDefault returns true if the given storage class is marked default,
+// false otherwise.
+func StorageClassIsDefault(sc *v1.StorageClass) bool {
+	value, found := sc.GetObjectMeta().GetAnnotations()[annStorageClassIsDefault]
+	if !found {
+		return false
+	}
+	boolValue, err := strconv.ParseBool(value)
+	if err != nil {
+		return false
+	}
+	return boolValue
+}
+
+// PatchStorageClassIsDefault changes the default flag of the given storage class.
+func PatchStorageClassIsDefault(cli storagev1.StorageV1Interface, name string, isDefault bool) error {
+	jsonPatch := fmt.Sprintf(`{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"%v"}}}`, isDefault)
+	if _, err := cli.StorageClasses().Patch(name, types.StrategicMergePatchType, []byte(jsonPatch)); err != nil {
+		return maskAny(err)
+	}
+	return nil
+}

pkg/util/k8sutil/storageclass_test.go

@@ -0,0 +1,72 @@
+//
+// DISCLAIMER
+//
+// Copyright 2018 ArangoDB GmbH, Cologne, Germany
+//
+// 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.
+//
+// Copyright holder is ArangoDB GmbH, Cologne, Germany
+//
+// Author Ewout Prangsma
+//
+
+package k8sutil
+
+import (
+	"testing"
+
+	"k8s.io/api/storage/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// StorageClassIsDefault returns true if the given storage class is marked default,
+// false otherwise.
+func TestStorageClassIsDefault(t *testing.T) {
+	tests := []struct {
+		StorageClass v1.StorageClass
+		IsDefault    bool
+	}{
+		{v1.StorageClass{
+			ObjectMeta: metav1.ObjectMeta{
+				Annotations: map[string]string{},
+			},
+		}, false},
+		{v1.StorageClass{
+			ObjectMeta: metav1.ObjectMeta{
+				Annotations: map[string]string{
+					annStorageClassIsDefault: "false",
+				},
+			},
+		}, false},
+		{v1.StorageClass{
+			ObjectMeta: metav1.ObjectMeta{
+				Annotations: map[string]string{
+					annStorageClassIsDefault: "foo",
+				},
+			},
+		}, false},
+		{v1.StorageClass{
+			ObjectMeta: metav1.ObjectMeta{
+				Annotations: map[string]string{
+					annStorageClassIsDefault: "true",
+				},
+			},
+		}, true},
+	}
+	for _, test := range tests {
+		result := StorageClassIsDefault(&test.StorageClass)
+		if result != test.IsDefault {
+			t.Errorf("StorageClassIsDefault failed. Expected %v, got %v for %#v", test.IsDefault, result, test.StorageClass)
+		}
+	}
+}