Docker及Kubernetes下device使用和分析

type ContainerAllocateResponse struct {
	// List of environment variable to be set in the container to access one of more devices.
	Envs map[string]string `protobuf:"bytes,1,rep,name=envs" json:"envs,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
	// Mounts for the container.
	Mounts []*Mount `protobuf:"bytes,2,rep,name=mounts" json:"mounts,omitempty"`
	// Devices for the container.
	Devices []*DeviceSpec `protobuf:"bytes,3,rep,name=devices" json:"devices,omitempty"`
	// Container annotations to pass to the container runtime
	Annotations map[string]string `protobuf:"bytes,4,rep,name=annotations" json:"annotations,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
}

// NewHostDevicePlugin returns an initialized HostDevicePlugin
func NewHostDevicePlugin(devCfg *DevConfig) (*HostDevicePlugin, error) {
	normalizedName, err := NomalizeDevName(devCfg.DevName)
	if err != nil {
		return nil, err
	}

  //要注册到Kubernetes的设备信息
	devs := []*pluginapi.Device {
		&pluginapi.Device{ID: devCfg.DevName, Health: pluginapi.Healthy},
	}

	return &HostDevicePlugin{
		DevName: 		devCfg.DevName,
		Permissions:    devCfg.Permissions,
		NormalizedName: normalizedName,
		ResourceName:   ResourceNamePrefix + normalizedName,
		UnixSockPath:   pluginapi.DevicePluginPath + normalizedName,
		Dev:			devs,
		StopChan: 		make(chan interface{}),
		IsRigistered: false,
	}, nil
}

// ListAndWatch lists devices and update that list according to the health status
func (plugin *HostDevicePlugin) ListAndWatch(e *pluginapi.Empty, s pluginapi.DevicePlugin_ListAndWatchServer) error {

	s.Send(&pluginapi.ListAndWatchResponse{Devices: plugin.Dev})

	ticker := time.NewTicker(time.Second * 10)

	for {
		select {
		case <-plugin.StopChan:
			return nil
		case <-ticker.C:
			s.Send(&pluginapi.ListAndWatchResponse{Devices: plugin.Dev})
		}
	}
	return nil
}

// Allocate which return list of devices.
func (plugin *HostDevicePlugin) Allocate(ctx context.Context, r *pluginapi.AllocateRequest) (*pluginapi.AllocateResponse, error) {
	//spew.Printf("Context: %#v\n", ctx)
	spew.Printf("AllocateRequest: %#v\n", *r)

	response := pluginapi.AllocateResponse{}

  //指定host和容器的device路径，以及读写权限
	devSpec := pluginapi.DeviceSpec {
		HostPath: plugin.DevName,
		ContainerPath: plugin.DevName,
		Permissions: plugin.Permissions,
	}

	//log.Debugf("Request IDs: %v", r)
	var devicesList []*pluginapi.ContainerAllocateResponse

  //构建返回给kubelet的device resource信息
	devicesList = append(devicesList, &pluginapi.ContainerAllocateResponse{
		Envs: make(map[string]string),
		Annotations: make(map[string]string),
		Devices: []*pluginapi.DeviceSpec{&devSpec},
		Mounts: nil,
	})

	response.ContainerResponses = devicesList

	spew.Printf("AllocateResponse: %#v\n", devicesList)

	return &response, nil
}