runtime: forward the stat and resize requests from shimv2 to kata agent

Translate the volume path from host-known path to guest-known path
and forward the request to kata agent.

Fixes: #3454

Signed-off-by: Feng Wang <feng.wang@databricks.com>

src/runtime/virtcontainers/agent.go

@@ -190,4 +190,10 @@ type agent interface {
 
 	// getAgentMetrics get metrics of agent and guest through agent
 	getAgentMetrics(context.Context, *grpc.GetMetricsRequest) (*grpc.Metrics, error)
+
+	//getGuestVolumeStats get the filesystem stats of a volume specified by the volume mount path on the guest.
+	getGuestVolumeStats(ctx context.Context, volumeGuestPath string) ([]byte, error)
+
+	// resizeGuestVolume resizes a volume specified by the volume mount path on the guest.
+	resizeGuestVolume(ctx context.Context, volumeGuestPath string, size uint64) error
 }

src/runtime/virtcontainers/interfaces.go

@@ -76,6 +76,9 @@ type VCSandbox interface {
 	UpdateRuntimeMetrics() error
 	GetAgentMetrics(ctx context.Context) (string, error)
 	GetAgentURL() (string, error)
+
+	GuestVolumeStats(ctx context.Context, volumePath string) ([]byte, error)
+	ResizeGuestVolume(ctx context.Context, volumePath string, size uint64) error
 }
 
 // VCContainer is the Container interface

src/runtime/virtcontainers/kata_agent.go

@@ -138,6 +138,8 @@ const (
 	grpcGetOOMEventRequest       = "grpc.GetOOMEventRequest"
 	grpcGetMetricsRequest        = "grpc.GetMetricsRequest"
 	grpcAddSwapRequest           = "grpc.AddSwapRequest"
+	grpcVolumeStatsRequest       = "grpc.VolumeStatsRequest"
+	grpcResizeVolumeRequest      = "grpc.ResizeVolumeRequest"
 )
 
 // newKataAgent returns an agent from an agent type.
@@ -1952,6 +1954,12 @@ func (k *kataAgent) installReqFunc(c *kataclient.AgentClient) {
 	k.reqHandlers[grpcAddSwapRequest] = func(ctx context.Context, req interface{}) (interface{}, error) {
 		return k.client.AgentServiceClient.AddSwap(ctx, req.(*grpc.AddSwapRequest))
 	}
+	k.reqHandlers[grpcVolumeStatsRequest] = func(ctx context.Context, req interface{}) (interface{}, error) {
+		return k.client.AgentServiceClient.GetVolumeStats(ctx, req.(*grpc.VolumeStatsRequest))
+	}
+	k.reqHandlers[grpcResizeVolumeRequest] = func(ctx context.Context, req interface{}) (interface{}, error) {
+		return k.client.AgentServiceClient.ResizeVolume(ctx, req.(*grpc.ResizeVolumeRequest))
+	}
 }
 
 func (k *kataAgent) getReqContext(ctx context.Context, reqName string) (newCtx context.Context, cancel context.CancelFunc) {
@@ -2169,3 +2177,22 @@ func (k *kataAgent) getAgentMetrics(ctx context.Context, req *grpc.GetMetricsReq
 
 	return resp.(*grpc.Metrics), nil
 }
+
+func (k *kataAgent) getGuestVolumeStats(ctx context.Context, volumeGuestPath string) ([]byte, error) {
+	result, err := k.sendReq(ctx, &grpc.VolumeStatsRequest{VolumeGuestPath: volumeGuestPath})
+	if err != nil {
+		return nil, err
+	}
+
+	buf, err := json.Marshal(result.(*grpc.VolumeStatsResponse))
+	if err != nil {
+		return nil, err
+	}
+
+	return buf, nil
+}
+
+func (k *kataAgent) resizeGuestVolume(ctx context.Context, volumeGuestPath string, size uint64) error {
+	_, err := k.sendReq(ctx, &grpc.ResizeVolumeRequest{VolumeGuestPath: volumeGuestPath, Size_: size})
+	return err
+}

src/runtime/virtcontainers/mock_agent.go

@@ -242,3 +242,11 @@ func (n *mockAgent) getOOMEvent(ctx context.Context) (string, error) {
 func (n *mockAgent) getAgentMetrics(ctx context.Context, req *grpc.GetMetricsRequest) (*grpc.Metrics, error) {
 	return nil, nil
 }
+
+func (n *mockAgent) getGuestVolumeStats(ctx context.Context, volumeGuestPath string) ([]byte, error) {
+	return nil, nil
+}
+
+func (n *mockAgent) resizeGuestVolume(ctx context.Context, volumeGuestPath string, size uint64) error {
+	return nil
+}

src/runtime/virtcontainers/pkg/vcmock/sandbox.go

@@ -254,3 +254,10 @@ func (s *Sandbox) GetAgentURL() (string, error) {
 func (s *Sandbox) GetHypervisorPid() (int, error) {
 	return 0, nil
 }
+
+func (s *Sandbox) GuestVolumeStats(ctx context.Context, path string) ([]byte, error) {
+	return nil, nil
+}
+func (s *Sandbox) ResizeGuestVolume(ctx context.Context, path string, size uint64) error {
+	return nil
+}

src/runtime/virtcontainers/sandbox.go

@@ -2257,6 +2257,43 @@ func (s *Sandbox) GetAgentURL() (string, error) {
 	return s.agent.getAgentURL()
 }
 
+// GuestVolumeStats return the filesystem stat of a given volume in the guest.
+func (s *Sandbox) GuestVolumeStats(ctx context.Context, volumePath string) ([]byte, error) {
+	guestMountPath, err := s.guestMountPath(volumePath)
+	if err != nil {
+		return nil, err
+	}
+	return s.agent.getGuestVolumeStats(ctx, guestMountPath)
+}
+
+// ResizeGuestVolume resizes a volume in the guest.
+func (s *Sandbox) ResizeGuestVolume(ctx context.Context, volumePath string, size uint64) error {
+	// TODO: https://github.com/kata-containers/kata-containers/issues/3694.
+	guestMountPath, err := s.guestMountPath(volumePath)
+	if err != nil {
+		return err
+	}
+	return s.agent.resizeGuestVolume(ctx, guestMountPath, size)
+}
+
+func (s *Sandbox) guestMountPath(volumePath string) (string, error) {
+	// verify the device even exists
+	if _, err := os.Stat(volumePath); err != nil {
+		s.Logger().WithError(err).WithField("volume", volumePath).Error("Cannot get stats for volume that doesn't exist")
+		return "", err
+	}
+
+	// verify that we have a mount in this sandbox who's source maps to this
+	for _, c := range s.containers {
+		for _, m := range c.mounts {
+			if volumePath == m.Source {
+				return m.GuestDeviceMount, nil
+			}
+		}
+	}
+	return "", fmt.Errorf("mount %s not found in sandbox", volumePath)
+}
+
 // getSandboxCPUSet returns the union of each of the sandbox's containers' CPU sets'
 // cpus and mems as a string in canonical linux CPU/mems list format
 func (s *Sandbox) getSandboxCPUSet() (string, string, error) {