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Cgroup for Go
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package cgroup | |
import "os" | |
import "syscall" | |
import "io/ioutil" | |
import "strconv" | |
import "os/exec" | |
import "strings" | |
import "errors" | |
const cgroupDir = "/sys/fs/cgroup" | |
type Subsys struct { | |
Sub string | |
Group string | |
} | |
func (ss *Subsys) convPath(name string) string { | |
return cgroupDir + "/" + ss.Sub + "/" + ss.Group + "/" + name | |
} | |
func (ss *Subsys) listChildren() ([]string, error) { | |
fis, err := ioutil.ReadDir(ss.convPath("")) | |
if err != nil { | |
return nil, err | |
} else { | |
groups := make([]string, 0, 10) | |
for i := range fis { | |
if fis[i].IsDir() { | |
groups = append(groups, fis[i].Name()) | |
} | |
} | |
return groups, nil | |
} | |
} | |
func (ss *Subsys) setVal(val, name string) error { | |
fp, err := os.OpenFile(ss.convPath(name), syscall.O_WRONLY, 0664) | |
if err != nil { | |
return err | |
} | |
defer fp.Close() | |
_, err = fp.Write([]byte(val)) | |
return err | |
} | |
func (ss *Subsys) setValInt(val int64, name string) error { | |
return ss.setVal(strconv.FormatInt(val, 10), name) | |
} | |
func (ss *Subsys) addVal(val, name string) error { | |
fp, err := os.OpenFile(ss.convPath(name), syscall.O_WRONLY|syscall.O_APPEND, 0664) | |
if err != nil { | |
return err | |
} | |
if err != nil { | |
return err | |
} | |
defer fp.Close() | |
_, err = fp.Write([]byte(val)) | |
return err | |
} | |
func (ss *Subsys) addValInt(val int64, name string) error { | |
return ss.addVal(strconv.FormatInt(val, 10)+"\n", name) | |
} | |
func (ss *Subsys) getVal(name string) (*string, error) { | |
fp, err := os.OpenFile(ss.convPath(name), syscall.O_RDONLY, 0664) | |
if err != nil { | |
return nil, err | |
} | |
defer fp.Close() | |
data, err := ioutil.ReadAll(fp) | |
if err != nil { | |
return nil, err | |
} | |
str := string(data) | |
return &str, nil | |
} | |
func (ss *Subsys) getValInt(name string) (int64, error) { | |
res, err := ss.getVal(name) | |
if err != nil { | |
return 0, err | |
} | |
var str string | |
if (*res)[len(*res)-1] == '\n' { | |
str = (*res)[0 : len(*res)-1] | |
} else { | |
str = *res | |
} | |
return strconv.ParseInt(str, 10, 64) | |
} | |
type Cgroup struct { | |
isCreated bool | |
name string | |
subsys []string | |
} | |
func (g *Cgroup) addSubsys(name string) *Cgroup { | |
g.subsys = append(g.subsys, name) | |
//g.libcg.AddController(name) | |
return g | |
} | |
func (g *Cgroup) getSubsys(name string) *Subsys { | |
return &Subsys{name, g.name} | |
} | |
func (g *Cgroup) Modify() error { | |
if g.isCreated { | |
return errors.New("Already created") | |
} | |
res, err := exec.Command("cgcreate", "-g", strings.Join(g.subsys, ",")+":/"+g.name).CombinedOutput() | |
if len(res) != 0 { | |
return errors.New("Failed to create a cgroup" + err.Error()) | |
} | |
g.isCreated = true | |
return nil | |
} | |
func (g *Cgroup) Delete() error { | |
if !g.isCreated { | |
return errors.New("Cgroup hasn't been created") | |
} | |
res, err := exec.Command("cgdelete", "-g", strings.Join(g.subsys, ",")+":/"+g.name).CombinedOutput() | |
if len(res) != 0 { | |
return errors.New("Failed to delete a cgroup " + err.Error()) | |
} | |
return nil | |
} | |
// NewCgroup created a new Cgroup struct | |
func NewCgroup(name string) Cgroup { | |
return Cgroup{false, name, []string{}} | |
} |
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func createNewTestGroup() (*cgroup.Cgroup, error) { | |
cg := NewCgroup(name) | |
err := cg.addSubsys("memory").Modify() | |
if err != nil { | |
return nil, errors.New("Failed to create a cgroup") | |
} | |
err = cg.getSubsys("memory").setValInt(mem, "memory.limit_in_bytes") | |
if err != nil { | |
cg.Delete() | |
return nil, errors.New("Failed to set memory.limit_in_bytes") | |
} | |
err = cg.getSubsys("memory").setValInt(mem, "memory.memsw.limit_in_bytes") | |
if err != nil { | |
cg.Delete() | |
return nil, errors.New("Failed to set memory.memsw.limit_in_bytes") | |
} | |
return cg, nil | |
} |
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