systemd: Lazy initialize the systemd dbus connection

Signed-off-by: Mrunal Patel <mrunalp@gmail.com>
This commit is contained in:
Mrunal Patel 2020-03-27 15:01:36 -07:00
parent 33c6125da6
commit d05e5728aa
2 changed files with 34 additions and 22 deletions

View File

@ -71,8 +71,9 @@ const (
) )
var ( var (
connLock sync.Mutex connOnce sync.Once
theConn *systemdDbus.Conn connDbus *systemdDbus.Conn
connErr error
) )
func newProp(name string, units interface{}) systemdDbus.Property { func newProp(name string, units interface{}) systemdDbus.Property {
@ -97,22 +98,13 @@ func IsRunningSystemd() bool {
return fi.IsDir() return fi.IsDir()
} }
func UseSystemd() bool { // getDbusConnection lazy initializes systemd dbus connection
if !isRunningSystemd() { // and returns it
return false func getDbusConnection() (*systemdDbus.Conn, error) {
} connOnce.Do(func() {
connDbus, connErr = systemdDbus.New()
connLock.Lock() })
defer connLock.Unlock() return connDbus, connErr
if theConn == nil {
var err error
theConn, err = systemdDbus.New()
if err != nil {
return false
}
}
return true
} }
func NewSystemdCgroupsManager() (func(config *configs.Cgroup, paths map[string]string) cgroups.Manager, error) { func NewSystemdCgroupsManager() (func(config *configs.Cgroup, paths map[string]string) cgroups.Manager, error) {
@ -247,8 +239,12 @@ func (m *LegacyManager) Apply(pid int) error {
properties = append(properties, c.SystemdProps...) properties = append(properties, c.SystemdProps...)
dbusConnection, err := getDbusConnection()
if err != nil {
return err
}
statusChan := make(chan string, 1) statusChan := make(chan string, 1)
if _, err := theConn.StartTransientUnit(unitName, "replace", properties, statusChan); err == nil { if _, err := dbusConnection.StartTransientUnit(unitName, "replace", properties, statusChan); err == nil {
select { select {
case <-statusChan: case <-statusChan:
case <-time.After(time.Second): case <-time.After(time.Second):
@ -284,7 +280,13 @@ func (m *LegacyManager) Destroy() error {
} }
m.mu.Lock() m.mu.Lock()
defer m.mu.Unlock() defer m.mu.Unlock()
theConn.StopUnit(getUnitName(m.Cgroups), "replace", nil)
dbusConnection, err := getDbusConnection()
if err != nil {
return err
}
dbusConnection.StopUnit(getUnitName(m.Cgroups), "replace", nil)
if err := cgroups.RemovePaths(m.Paths); err != nil { if err := cgroups.RemovePaths(m.Paths); err != nil {
return err return err
} }

View File

@ -119,8 +119,13 @@ func (m *UnifiedManager) Apply(pid int) error {
// ignore c.Resources.KernelMemory // ignore c.Resources.KernelMemory
dbusConnection, err := getDbusConnection()
if err != nil {
return err
}
statusChan := make(chan string, 1) statusChan := make(chan string, 1)
if _, err := theConn.StartTransientUnit(unitName, "replace", properties, statusChan); err == nil { if _, err := dbusConnection.StartTransientUnit(unitName, "replace", properties, statusChan); err == nil {
select { select {
case <-statusChan: case <-statusChan:
case <-time.After(time.Second): case <-time.After(time.Second):
@ -155,7 +160,12 @@ func (m *UnifiedManager) Destroy() error {
} }
m.mu.Lock() m.mu.Lock()
defer m.mu.Unlock() defer m.mu.Unlock()
theConn.StopUnit(getUnitName(m.Cgroups), "replace", nil)
dbusConnection, err := getDbusConnection()
if err != nil {
return err
}
dbusConnection.StopUnit(getUnitName(m.Cgroups), "replace", nil)
if err := cgroups.RemovePaths(m.Paths); err != nil { if err := cgroups.RemovePaths(m.Paths); err != nil {
return err return err
} }