Map PV access modes to CSI access modes

accessmodes/access_modes.go

@@ -0,0 +1,128 @@
+/*
+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 accessmodes
+
+import (
+	"fmt"
+
+	"github.com/container-storage-interface/spec/lib/go/csi"
+	v1 "k8s.io/api/core/v1"
+)
+
+// ToCSIAccessMode maps PersistentVolume access modes in Kubernetes to CSI
+// access modes. Which mapping is used depends if the driver supports the
+// SINGLE_NODE_MULTI_WRITER capability.
+func ToCSIAccessMode(pvAccessModes []v1.PersistentVolumeAccessMode, supportsSingleNodeMultiWriter bool) (csi.VolumeCapability_AccessMode_Mode, error) {
+	if supportsSingleNodeMultiWriter {
+		return toSingleNodeMultiWriterCapableCSIAccessMode(pvAccessModes)
+	}
+	return toCSIAccessMode(pvAccessModes)
+}
+
+// toCSIAccessMode maps PersistentVolume access modes in Kubernetes to CSI
+// access modes.
+//
+// +------------------+-------------------------+----------------------------------------+
+// |  K8s AccessMode  |     CSI AccessMode      |           Additional Details           |
+// +------------------+-------------------------+----------------------------------------+
+// | ReadWriteMany    | MULTI_NODE_MULTI_WRITER |                                        |
+// | ReadOnlyMany     | MULTI_NODE_READER_ONLY  | Cannot be combined with ReadWriteOnce  |
+// | ReadWriteOnce    | SINGLE_NODE_WRITER      | Cannot be combined with ReadOnlyMany   |
+// | ReadWriteOncePod | SINGLE_NODE_WRITER      | Cannot be combined with any AccessMode |
+// +------------------+-------------------------+----------------------------------------+
+func toCSIAccessMode(pvAccessModes []v1.PersistentVolumeAccessMode) (csi.VolumeCapability_AccessMode_Mode, error) {
+	m := uniqueAccessModes(pvAccessModes)
+
+	switch {
+	// This mapping exists to enable CSI drivers that lack the
+	// SINGLE_NODE_MULTI_WRITER capability to work with the
+	// ReadWriteOncePod access mode.
+	case m[v1.ReadWriteOncePod]:
+		if len(m) > 1 {
+			return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("Kubernetes does not support use of ReadWriteOncePod with other access modes on the same PersistentVolume")
+		}
+		return csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER, nil
+
+	case m[v1.ReadWriteMany]:
+		// ReadWriteMany takes precedence, regardless of what other
+		// modes are set.
+		return csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER, nil
+
+	case m[v1.ReadOnlyMany] && m[v1.ReadWriteOnce]:
+		// This is not possible in the CSI spec.
+		return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("CSI does not support ReadOnlyMany and ReadWriteOnce on the same PersistentVolume")
+
+	case m[v1.ReadOnlyMany]:
+		return csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY, nil
+
+	case m[v1.ReadWriteOnce]:
+		return csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER, nil
+
+	default:
+		return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("unsupported AccessMode combination: %+v", pvAccessModes)
+	}
+}
+
+// toSingleNodeMultiWriterCapableCSIAccessMode maps PersistentVolume access
+// modes in Kubernetes to CSI access modes for drivers that support the
+// SINGLE_NODE_MULTI_WRITER capability.
+//
+// +------------------+---------------------------+----------------------------------------+
+// |  K8s AccessMode  |      CSI AccessMode       |           Additional Details           |
+// +------------------+---------------------------+----------------------------------------+
+// | ReadWriteMany    | MULTI_NODE_MULTI_WRITER   |                                        |
+// | ReadOnlyMany     | MULTI_NODE_READER_ONLY    | Cannot be combined with ReadWriteOnce  |
+// | ReadWriteOnce    | SINGLE_NODE_MULTI_WRITER  | Cannot be combined with ReadOnlyMany   |
+// | ReadWriteOncePod | SINGLE_NODE_SINGLE_WRITER | Cannot be combined with any AccessMode |
+// +------------------+---------------------------+----------------------------------------+
+func toSingleNodeMultiWriterCapableCSIAccessMode(pvAccessModes []v1.PersistentVolumeAccessMode) (csi.VolumeCapability_AccessMode_Mode, error) {
+	m := uniqueAccessModes(pvAccessModes)
+
+	switch {
+	case m[v1.ReadWriteOncePod]:
+		if len(m) > 1 {
+			return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("Kubernetes does not support use of ReadWriteOncePod with other access modes on the same PersistentVolume")
+		}
+		return csi.VolumeCapability_AccessMode_SINGLE_NODE_SINGLE_WRITER, nil
+
+	case m[v1.ReadWriteMany]:
+		// ReadWriteMany trumps everything, regardless of what other
+		// modes are set.
+		return csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER, nil
+
+	case m[v1.ReadOnlyMany] && m[v1.ReadWriteOnce]:
+		// This is not possible in the CSI spec.
+		return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("CSI does not support ReadOnlyMany and ReadWriteOnce on the same PersistentVolume")
+
+	case m[v1.ReadOnlyMany]:
+		return csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY, nil
+
+	case m[v1.ReadWriteOnce]:
+		return csi.VolumeCapability_AccessMode_SINGLE_NODE_MULTI_WRITER, nil
+
+	default:
+		return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("unsupported AccessMode combination: %+v", pvAccessModes)
+	}
+}
+
+func uniqueAccessModes(pvAccessModes []v1.PersistentVolumeAccessMode) map[v1.PersistentVolumeAccessMode]bool {
+	m := map[v1.PersistentVolumeAccessMode]bool{}
+	for _, mode := range pvAccessModes {
+		m[mode] = true
+	}
+	return m
+}

accessmodes/access_modes_test.go

@@ -0,0 +1,134 @@
+/*
+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 accessmodes
+
+import (
+	"testing"
+
+	"github.com/container-storage-interface/spec/lib/go/csi"
+	v1 "k8s.io/api/core/v1"
+)
+
+func TestToCSIAccessMode(t *testing.T) {
+	tests := []struct {
+		name                          string
+		pvAccessModes                 []v1.PersistentVolumeAccessMode
+		expectedCSIAccessMode         csi.VolumeCapability_AccessMode_Mode
+		expectError                   bool
+		supportsSingleNodeMultiWriter bool
+	}{
+		{
+			name:                  "RWX",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{v1.ReadWriteMany},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER,
+		},
+		{
+			name:                  "ROX + RWO",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{v1.ReadOnlyMany, v1.ReadWriteOnce},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_UNKNOWN,
+			expectError:           true,
+		},
+		{
+			name:                  "ROX + RWOP",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{v1.ReadOnlyMany, v1.ReadWriteOncePod},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_UNKNOWN,
+			expectError:           true,
+		},
+		{
+			name:                  "ROX",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{v1.ReadOnlyMany},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY,
+		},
+		{
+			name:                  "RWO",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{v1.ReadWriteOnce},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER,
+		},
+		{
+			name:                  "RWOP",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{v1.ReadWriteOncePod},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER,
+		},
+		{
+			name:                  "empty",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_UNKNOWN,
+			expectError:           true,
+		},
+		{
+			name:                          "RWX with SINGLE_NODE_MULTI_WRITER capable driver",
+			pvAccessModes:                 []v1.PersistentVolumeAccessMode{v1.ReadWriteMany},
+			expectedCSIAccessMode:         csi.VolumeCapability_AccessMode_MULTI_NODE_MULTI_WRITER,
+			supportsSingleNodeMultiWriter: true,
+		},
+		{
+			name:                          "ROX + RWO with SINGLE_NODE_MULTI_WRITER capable driver",
+			pvAccessModes:                 []v1.PersistentVolumeAccessMode{v1.ReadOnlyMany, v1.ReadWriteOnce},
+			expectedCSIAccessMode:         csi.VolumeCapability_AccessMode_UNKNOWN,
+			expectError:                   true,
+			supportsSingleNodeMultiWriter: true,
+		},
+		{
+			name:                          "ROX + RWOP with SINGLE_NODE_MULTI_WRITER capable driver",
+			pvAccessModes:                 []v1.PersistentVolumeAccessMode{v1.ReadOnlyMany, v1.ReadWriteOncePod},
+			expectedCSIAccessMode:         csi.VolumeCapability_AccessMode_UNKNOWN,
+			expectError:                   true,
+			supportsSingleNodeMultiWriter: true,
+		},
+		{
+			name:                          "ROX with SINGLE_NODE_MULTI_WRITER capable driver",
+			pvAccessModes:                 []v1.PersistentVolumeAccessMode{v1.ReadOnlyMany},
+			expectedCSIAccessMode:         csi.VolumeCapability_AccessMode_MULTI_NODE_READER_ONLY,
+			supportsSingleNodeMultiWriter: true,
+		},
+		{
+			name:                          "RWO with SINGLE_NODE_MULTI_WRITER capable driver",
+			pvAccessModes:                 []v1.PersistentVolumeAccessMode{v1.ReadWriteOnce},
+			expectedCSIAccessMode:         csi.VolumeCapability_AccessMode_SINGLE_NODE_MULTI_WRITER,
+			supportsSingleNodeMultiWriter: true,
+		},
+		{
+			name:                          "RWOP with SINGLE_NODE_MULTI_WRITER capable driver",
+			pvAccessModes:                 []v1.PersistentVolumeAccessMode{v1.ReadWriteOncePod},
+			expectedCSIAccessMode:         csi.VolumeCapability_AccessMode_SINGLE_NODE_SINGLE_WRITER,
+			supportsSingleNodeMultiWriter: true,
+		},
+		{
+			name:                          "empty with SINGLE_NODE_MULTI_WRITER capable driver",
+			pvAccessModes:                 []v1.PersistentVolumeAccessMode{},
+			expectedCSIAccessMode:         csi.VolumeCapability_AccessMode_UNKNOWN,
+			expectError:                   true,
+			supportsSingleNodeMultiWriter: true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			csiAccessMode, err := ToCSIAccessMode(test.pvAccessModes, test.supportsSingleNodeMultiWriter)
+
+			if err == nil && test.expectError {
+				t.Errorf("test %s: expected error, got none", test.name)
+			}
+			if err != nil && !test.expectError {
+				t.Errorf("test %s: got error: %s", test.name, err)
+			}
+			if !test.expectError && csiAccessMode != test.expectedCSIAccessMode {
+				t.Errorf("test %s: unexpected access mode: %+v", test.name, csiAccessMode)
+			}
+		})
+	}
+}

go.mod

@@ -2,24 +2,25 @@ module github.com/kubernetes-csi/csi-lib-utils
 
 go 1.16
 
+// TODO(chrishenzie): Replace v0.22.0-beta.1 with v0.22.0 once release is cut.
 require (
 	github.com/container-storage-interface/spec v1.5.0
-	github.com/golang/protobuf v1.4.3
-	github.com/stretchr/testify v1.6.1
-	golang.org/x/net v0.0.0-20210224082022-3d97a244fca7
-	google.golang.org/grpc v1.37.0
-	k8s.io/api v0.21.1
-	k8s.io/client-go v0.21.1
-	k8s.io/component-base v0.21.1
-	k8s.io/klog/v2 v2.8.0
+	github.com/golang/protobuf v1.5.2
+	github.com/stretchr/testify v1.7.0
+	golang.org/x/net v0.0.0-20210520170846-37e1c6afe023
+	google.golang.org/grpc v1.38.0
+	k8s.io/api v0.22.0-beta.1
+	k8s.io/client-go v0.22.0-beta.1
+	k8s.io/component-base v0.22.0-beta.1
+	k8s.io/klog/v2 v2.9.0
 )
 
-replace k8s.io/api => k8s.io/api v0.21.1
+replace k8s.io/api => k8s.io/api v0.22.0-beta.1
 
-replace k8s.io/apimachinery => k8s.io/apimachinery v0.21.1
+replace k8s.io/apimachinery => k8s.io/apimachinery v0.22.0-beta.1
 
-replace k8s.io/client-go => k8s.io/client-go v0.21.1
+replace k8s.io/client-go => k8s.io/client-go v0.22.0-beta.1
 
-replace k8s.io/component-base => k8s.io/component-base v0.21.1
+replace k8s.io/component-base => k8s.io/component-base v0.22.0-beta.1
 
-replace k8s.io/node-api => k8s.io/node-api v0.21.1
+replace k8s.io/node-api => k8s.io/node-api v0.22.0-beta.1