cgroup

Documentation

Overview

Package cgroup provides an interface to read and write configuration to cgroup.

Index

• Variables
• func IsOnlyV2() bool
• func LikelySystemdPath(path string) bool
• func RangeToBits(str string) ([]byte, error)
• func TransformSystemdPath(path, cid string, rootless bool) (string, error)
• type Cgroup
  • func CreateMockSystemdCgroup() Cgroup
  • func NewFromPath(cgroupsPath string, useSystemd bool) (Cgroup, error)
  • func NewFromPid(pid int, useSystemd bool) (Cgroup, error)
• type CgroupJSON
  • func (c *CgroupJSON) MarshalJSON() ([]byte, error)
  • func (c *CgroupJSON) UnmarshalJSON(data []byte) error

Variables

var (
	ErrInvalidFormat    = errors.New("cgroup: parsing file with invalid format failed")
	ErrInvalidGroupPath = errors.New("cgroup: invalid group path")
)

var (
	// ErrBadResourceSpec indicates that a cgroupSystemd function was
	// passed a specs.LinuxResources object that is impossible or illegal
	// to process.
	ErrBadResourceSpec = errors.New("misconfigured resource spec")
	// ErrInvalidSlice indicates that the slice name passed via cgroup.Path is
	// invalid.
	ErrInvalidSlice = errors.New("invalid slice name")
)

Functions

func IsOnlyV2

func IsOnlyV2() bool

IsOnlyV2 checks whether cgroups V2 is enabled and V1 is not.

func LikelySystemdPath

func LikelySystemdPath(path string) bool

LikelySystemdPath returns true if the path looks like a systemd path. This is by no means an exhaustive check, it's just a useful proxy for logging a warning.

func RangeToBits

func RangeToBits(str string) ([]byte, error)

RangeToBits converts a text representation of a CPU mask (as written to or read from cgroups' cpuset.* files, e.g. "1,3-5") to a slice of bytes with the corresponding bits set (as consumed by systemd over dbus as AllowedCPUs/AllowedMemoryNodes unit property value). Copied from runc.

func TransformSystemdPath

func TransformSystemdPath(path, cid string, rootless bool) (string, error)

TransformSystemdPath transforms systemd path to be in the form `slice:prefix:name`. It returns an error if path could not be parsed as a valid systemd path.

Types

type Cgroup

type Cgroup interface {
	Install(res *specs.LinuxResources) error
	Uninstall() error
	Join() (func(), error)
	CPUQuota() (float64, error)
	CPUUsage() (uint64, error)
	NumCPU() (int, error)
	MemoryLimit() (uint64, error)
	MakePath(controllerName string) string
}

Cgroup represents a cgroup configuration.

func CreateMockSystemdCgroup

func CreateMockSystemdCgroup() Cgroup

CreateMockSystemdCgroup returns a mock Cgroup configured for systemd. This is useful for testing.

func NewFromPath

func NewFromPath(cgroupsPath string, useSystemd bool) (Cgroup, error)

NewFromPath creates a new Cgroup instance from the specified relative path. Cgroup paths are loaded based on the current process. If useSystemd is true, the Cgroup will be created and managed with systemd. This requires systemd (>=v244) to be running on the host and the cgroup path to be in the form `slice:prefix:name`.

func NewFromPid

func NewFromPid(pid int, useSystemd bool) (Cgroup, error)

NewFromPid loads cgroup for the given process. If useSystemd is true, the Cgroup will be created and managed with systemd. This requires systemd (>=v244) to be running on the host and the cgroup path to be in the form `slice:prefix:name`.

type CgroupJSON

type CgroupJSON struct {
	Cgroup Cgroup
}

CgroupJSON is a wrapper for Cgroup that can be encoded to JSON.

func (*CgroupJSON) MarshalJSON

func (c *CgroupJSON) MarshalJSON() ([]byte, error)

MarshalJSON implements json.Marshaler.MarshalJSON

func (*CgroupJSON) UnmarshalJSON

func (c *CgroupJSON) UnmarshalJSON(data []byte) error

UnmarshalJSON implements json.Unmarshaler.UnmarshalJSON