Map PV access modes to CSI access modes

kubernetes-csi · Jun 2, 2021 · a659c3d · a659c3d
1 parent e7ee9ab
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diff --git a/accessmodes/access_modes.go b/accessmodes/access_modes.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 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.
+func ToCSIAccessMode(pvAccessModes []v1.PersistentVolumeAccessMode) (csi.VolumeCapability_AccessMode_Mode, error) {
+	m := uniqueAccessModes(pvAccessModes)
+
+	switch {
+	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] && m[v1.ReadWriteOncePod]:
+		// This is not possible in the CSI spec.
+		return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("CSI does not support ReadOnlyMany and ReadWriteOncePod 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
+
+	// 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]:
+		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.
+func ToSingleNodeMultiWriterCapableCSIAccessMode(pvAccessModes []v1.PersistentVolumeAccessMode) (csi.VolumeCapability_AccessMode_Mode, error) {
+	m := uniqueAccessModes(pvAccessModes)
+
+	switch {
+	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] && m[v1.ReadWriteOncePod]:
+		// This is not possible in the CSI spec.
+		return csi.VolumeCapability_AccessMode_UNKNOWN, fmt.Errorf("CSI does not support ReadOnlyMany and ReadWriteOncePod 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
+
+	case m[v1.ReadWriteOncePod]:
+		return csi.VolumeCapability_AccessMode_SINGLE_NODE_SINGLE_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
+}
diff --git a/accessmodes/access_modes_test.go b/accessmodes/access_modes_test.go
@@ -0,0 +1,152 @@
+/*
+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
+	}{
+		{
+			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,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			csiAccessMode, err := ToCSIAccessMode(test.pvAccessModes)
+
+			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)
+			}
+		})
+	}
+}
+
+func TestToSingleNodeMultiWriterCapableCSIAccessMode(t *testing.T) {
+	tests := []struct {
+		name                  string
+		pvAccessModes         []v1.PersistentVolumeAccessMode
+		expectedCSIAccessMode csi.VolumeCapability_AccessMode_Mode
+		expectError           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_MULTI_WRITER,
+		},
+		{
+			name:                  "RWOP",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{v1.ReadWriteOncePod},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_SINGLE_NODE_SINGLE_WRITER,
+		},
+		{
+			name:                  "empty",
+			pvAccessModes:         []v1.PersistentVolumeAccessMode{},
+			expectedCSIAccessMode: csi.VolumeCapability_AccessMode_UNKNOWN,
+			expectError:           true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			csiAccessMode, err := ToSingleNodeMultiWriterCapableCSIAccessMode(test.pvAccessModes)
+
+			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)
+			}
+		})
+	}
+}