Implement metrics for RBD plugin

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

pkg/csi-common/nodeserver-default.go

@@ -17,16 +17,24 @@ limitations under the License.
 package csicommon
 
 import (
+	"fmt"
+	"os"
+
+	"github.com/ceph/ceph-csi/pkg/util"
+
 	"github.com/container-storage-interface/spec/lib/go/csi"
+	csipbv1 "github.com/container-storage-interface/spec/lib/go/csi"
 	"golang.org/x/net/context"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 	"k8s.io/klog"
+	"k8s.io/kubernetes/pkg/volume"
 )
 
 // DefaultNodeServer stores driver object
 type DefaultNodeServer struct {
 	Driver *CSIDriver
+	Type   string
 }
 
 // NodeStageVolume returns unimplemented response
@@ -71,6 +79,96 @@ func (ns *DefaultNodeServer) NodeGetCapabilities(ctx context.Context, req *csi.N
 }
 
 // NodeGetVolumeStats returns volume stats
-func (ns *DefaultNodeServer) NodeGetVolumeStats(ctx context.Context, in *csi.NodeGetVolumeStatsRequest) (*csi.NodeGetVolumeStatsResponse, error) {
-	return nil, status.Error(codes.Unimplemented, "")
+func (ns *DefaultNodeServer) NodeGetVolumeStats(ctx context.Context, req *csi.NodeGetVolumeStatsRequest) (*csi.NodeGetVolumeStatsResponse, error) {
+
+	var err error
+	targetPath := req.GetVolumePath()
+	if targetPath == "" {
+		err = fmt.Errorf("targetpath %v is empty", targetPath)
+		return nil, status.Error(codes.InvalidArgument, err.Error())
+	}
+	/*
+		volID := req.GetVolumeId()
+
+		TODO: Map the volumeID to the targetpath.
+
+		CephFS:
+		   we need secret to connect to the ceph cluster to get the volumeID from volume
+		   Name, however `secret` field/option is not available  in NodeGetVolumeStats spec,
+		   Below issue covers this request and once its available, we can do the validation
+		   as per the spec.
+
+		   https://github.com/container-storage-interface/spec/issues/371
+
+		RBD:
+		   Below issue covers this request for RBD and once its available, we can do the validation
+		   as per the spec.
+
+		   https://github.com/ceph/ceph-csi/issues/511
+
+	*/
+
+	isMnt, err := util.IsMountPoint(targetPath)
+
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, status.Errorf(codes.InvalidArgument, "targetpath %s doesnot exist", targetPath)
+		}
+		return nil, err
+	}
+	if !isMnt {
+		return nil, status.Errorf(codes.InvalidArgument, "targetpath %s is not mounted", targetPath)
+	}
+
+	cephMetricsProvider := volume.NewMetricsStatFS(targetPath)
+	volMetrics, volMetErr := cephMetricsProvider.GetMetrics()
+	if volMetErr != nil {
+		return nil, status.Error(codes.Internal, volMetErr.Error())
+	}
+
+	available, ok := (*(volMetrics.Available)).AsInt64()
+	if !ok {
+		klog.Errorf("failed to fetch available bytes")
+	}
+	capacity, ok := (*(volMetrics.Capacity)).AsInt64()
+	if !ok {
+		klog.Errorf("failed to fetch capacity bytes")
+		return nil, status.Error(codes.Unknown, "failed to fetch capacity bytes")
+	}
+	used, ok := (*(volMetrics.Used)).AsInt64()
+	if !ok {
+		klog.Errorf("failed to fetch used bytes")
+	}
+	inodes, ok := (*(volMetrics.Inodes)).AsInt64()
+	if !ok {
+		klog.Errorf("failed to fetch available inodes")
+		return nil, status.Error(codes.Unknown, "failed to fetch available inodes")
+
+	}
+	inodesFree, ok := (*(volMetrics.InodesFree)).AsInt64()
+	if !ok {
+		klog.Errorf("failed to fetch free inodes")
+	}
+
+	inodesUsed, ok := (*(volMetrics.InodesUsed)).AsInt64()
+	if !ok {
+		klog.Errorf("failed to fetch used inodes")
+	}
+	return &csi.NodeGetVolumeStatsResponse{
+		Usage: []*csi.VolumeUsage{
+			{
+				Available: available,
+				Total:     capacity,
+				Used:      used,
+				Unit:      csipbv1.VolumeUsage_BYTES,
+			},
+			{
+				Available: inodesFree,
+				Total:     inodes,
+				Used:      inodesUsed,
+				Unit:      csipbv1.VolumeUsage_INODES,
+			},
+		},
+	}, nil
+
 }

pkg/csi-common/utils.go

@@ -46,9 +46,10 @@ func NewVolumeCapabilityAccessMode(mode csi.VolumeCapability_AccessMode_Mode) *c
 }
 
 // NewDefaultNodeServer initializes default node server
-func NewDefaultNodeServer(d *CSIDriver) *DefaultNodeServer {
+func NewDefaultNodeServer(d *CSIDriver, t string) *DefaultNodeServer {
 	return &DefaultNodeServer{
 		Driver: d,
+		Type:   t,
 	}
 }