csi: Implement NodeServiceCapability_RPC_GET_VOLUME_STATS rpc call

and implement Metrics Provider for CSI driver

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

pkg/volume/csi/csi_metrics_test.go

@@ -0,0 +1,113 @@
+/*
+Copyright 2019 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 csi
+
+import (
+	"io"
+	"testing"
+
+	csipbv1 "github.com/container-storage-interface/spec/lib/go/csi"
+	"k8s.io/apimachinery/pkg/api/resource"
+	"k8s.io/kubernetes/pkg/volume/csi/fake"
+)
+
+func TestGetMetrics(t *testing.T) {
+	tests := []struct {
+		name          string
+		volumeID      string
+		targetPath    string
+		expectSuccess bool
+	}{
+		{
+			name:          "with valid name and volume id",
+			expectSuccess: true,
+			volumeID:      "foobar",
+			targetPath:    "/mnt/foo",
+		},
+	}
+
+	for _, tc := range tests {
+		metricsGetter := &metricsCsi{volumeID: tc.volumeID, targetPath: tc.targetPath}
+		metricsGetter.csiClient = &csiDriverClient{
+			driverName: "com.google.gcepd",
+			nodeV1ClientCreator: func(addr csiAddr) (csipbv1.NodeClient, io.Closer, error) {
+				nodeClient := fake.NewNodeClientWithVolumeStats(true /* VolumeStatsCapable */)
+				fakeCloser := fake.NewCloser(t)
+				nodeClient.SetNodeVolumeStatsResp(getRawVolumeInfo())
+				return nodeClient, fakeCloser, nil
+			},
+		}
+		metrics, err := metricsGetter.GetMetrics()
+		if err != nil {
+			t.Fatalf("for %s: unexpected error : %v", tc.name, err)
+		}
+		if metrics == nil {
+			t.Fatalf("unexpected nil metrics")
+		}
+		expectedMetrics := getRawVolumeInfo()
+		for _, usage := range expectedMetrics.Usage {
+			if usage.Unit == csipbv1.VolumeUsage_BYTES {
+				availableBytes := resource.NewQuantity(usage.Available, resource.BinarySI)
+				totalBytes := resource.NewQuantity(usage.Total, resource.BinarySI)
+				usedBytes := resource.NewQuantity(usage.Used, resource.BinarySI)
+				if metrics.Available.Cmp(*availableBytes) != 0 {
+					t.Fatalf("for %s: error: expected :%v , got: %v", tc.name, *availableBytes, *(metrics.Available))
+				}
+				if metrics.Capacity.Cmp(*totalBytes) != 0 {
+					t.Fatalf("for %s: error: expected :%v , got: %v", tc.name, *totalBytes, *(metrics.Capacity))
+				}
+				if metrics.Used.Cmp(*usedBytes) != 0 {
+					t.Fatalf("for %s: error: expected :%v , got: %v", tc.name, *usedBytes, *(metrics.Used))
+				}
+			}
+
+			if usage.Unit == csipbv1.VolumeUsage_INODES {
+				freeInodes := resource.NewQuantity(usage.Available, resource.BinarySI)
+				inodes := resource.NewQuantity(usage.Total, resource.BinarySI)
+				usedInodes := resource.NewQuantity(usage.Used, resource.BinarySI)
+				if metrics.InodesFree.Cmp(*freeInodes) != 0 {
+					t.Fatalf("for %s: error: expected :%v , got: %v", tc.name, *freeInodes, *(metrics.InodesFree))
+				}
+				if metrics.Inodes.Cmp(*inodes) != 0 {
+					t.Fatalf("for %s: error: expected :%v , got: %v", tc.name, *inodes, *(metrics.Inodes))
+				}
+				if metrics.InodesUsed.Cmp(*usedInodes) != 0 {
+					t.Fatalf("for %s: error: expected :%v , got: %v", tc.name, *usedInodes, *(metrics.InodesUsed))
+				}
+			}
+		}
+	}
+}
+
+func getRawVolumeInfo() *csipbv1.NodeGetVolumeStatsResponse {
+	return &csipbv1.NodeGetVolumeStatsResponse{
+		Usage: []*csipbv1.VolumeUsage{
+			{
+				Available: int64(10),
+				Total:     int64(10),
+				Used:      int64(2),
+				Unit:      csipbv1.VolumeUsage_BYTES,
+			},
+			{
+				Available: int64(100),
+				Total:     int64(100),
+				Used:      int64(20),
+				Unit:      csipbv1.VolumeUsage_INODES,
+			},
+		},
+	}
+}