Golang Interface.List方法代码示例

// checks if the required cgroups subsystems are mounted.
// As of now, only 'cpu' and 'memory' are required.
func validateSystemRequirements(mountUtil mount.Interface) error {
	const (
		cgroupMountType = "cgroup"
		localErr        = "system validation failed"
	)
	mountPoints, err := mountUtil.List()
	if err != nil {
		return fmt.Errorf("%s - %v", localErr, err)
	}
	expectedCgroups := sets.NewString("cpu", "cpuacct", "cpuset", "memory")
	for _, mountPoint := range mountPoints {
		if mountPoint.Type == cgroupMountType {
			for _, opt := range mountPoint.Opts {
				if expectedCgroups.Has(opt) {
					expectedCgroups.Delete(opt)
				}
			}
		}
	}

	if expectedCgroups.Len() > 0 {
		return fmt.Errorf("%s - Following Cgroup subsystem not mounted: %v", localErr, expectedCgroups.List())
	}
	return nil
}

// getDevicePrefixRefCount: given a prefix of device path, find its reference count from /proc/mounts
// returns the reference count to the device and error code
// for services like iscsi construct multiple device paths with the same prefix pattern.
// this function aggregates all references to a service based on the prefix pattern
// More specifically, this prefix semantics is to aggregate disk paths that belong to the same iSCSI target/iqn pair.
// an iSCSI target could expose multiple LUNs through the same IQN, and Linux iSCSI initiator creates disk paths that start the same prefix but end with different LUN number
// When we decide whether it is time to logout a target, we have to see if none of the LUNs are used any more.
// That's where the prefix based ref count kicks in. If we only count the disks using exact match, we could log other disks out.
func getDevicePrefixRefCount(mounter mount.Interface, deviceNamePrefix string) (int, error) {
	mps, err := mounter.List()
	if err != nil {
		return -1, err
	}

	// Find the number of references to the device.
	refCount := 0
	for i := range mps {
		if strings.HasPrefix(mps[i].Path, deviceNamePrefix) {
			refCount++
		}
	}
	return refCount, nil
}

// checks if the required cgroups subsystems are mounted.
// As of now, only 'cpu' and 'memory' are required.
// cpu quota is a soft requirement.
func validateSystemRequirements(mountUtil mount.Interface) (features, error) {
	const (
		cgroupMountType = "cgroup"
		localErr        = "system validation failed"
	)
	var (
		cpuMountPoint string
		f             features
	)
	mountPoints, err := mountUtil.List()
	if err != nil {
		return f, fmt.Errorf("%s - %v", localErr, err)
	}

	expectedCgroups := sets.NewString("cpu", "cpuacct", "cpuset", "memory")
	for _, mountPoint := range mountPoints {
		if mountPoint.Type == cgroupMountType {
			for _, opt := range mountPoint.Opts {
				if expectedCgroups.Has(opt) {
					expectedCgroups.Delete(opt)
				}
				if opt == "cpu" {
					cpuMountPoint = mountPoint.Path
				}
			}
		}
	}

	if expectedCgroups.Len() > 0 {
		return f, fmt.Errorf("%s - Following Cgroup subsystem not mounted: %v", localErr, expectedCgroups.List())
	}

	// Check if cpu quota is available.
	// CPU cgroup is required and so it expected to be mounted at this point.
	periodExists, err := util.FileExists(path.Join(cpuMountPoint, "cpu.cfs_period_us"))
	if err != nil {
		glog.Errorf("failed to detect if CPU cgroup cpu.cfs_period_us is available - %v", err)
	}
	quotaExists, err := util.FileExists(path.Join(cpuMountPoint, "cpu.cfs_quota_us"))
	if err != nil {
		glog.Errorf("failed to detect if CPU cgroup cpu.cfs_quota_us is available - %v", err)
	}
	if quotaExists && periodExists {
		f.cpuHardcapping = true
	}
	return f, nil
}