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moby--moby/daemon/state.go
Alexandr Morozov f1975cbc7c
Fix race on state serialization
Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
2014-08-14 21:51:15 +04:00

198 lines
4 KiB
Go

package daemon
import (
"encoding/json"
"fmt"
"sync"
"time"
"github.com/docker/docker/pkg/units"
)
type State struct {
sync.RWMutex
Running bool
Paused bool
Restarting bool
Pid int
ExitCode int
StartedAt time.Time
FinishedAt time.Time
waitChan chan struct{}
}
func NewState() *State {
return &State{
waitChan: make(chan struct{}),
}
}
// String returns a human-readable description of the state
func (s *State) String() string {
s.RLock()
defer s.RUnlock()
if s.Running {
if s.Paused {
return fmt.Sprintf("Up %s (Paused)", units.HumanDuration(time.Now().UTC().Sub(s.StartedAt)))
}
if s.Restarting {
return fmt.Sprintf("Restarting (%d) %s ago", s.ExitCode, units.HumanDuration(time.Now().UTC().Sub(s.FinishedAt)))
}
return fmt.Sprintf("Up %s", units.HumanDuration(time.Now().UTC().Sub(s.StartedAt)))
}
if s.FinishedAt.IsZero() {
return ""
}
return fmt.Sprintf("Exited (%d) %s ago", s.ExitCode, units.HumanDuration(time.Now().UTC().Sub(s.FinishedAt)))
}
type jState State
// MarshalJSON for state is needed to avoid race conditions on inspect
func (s *State) MarshalJSON() ([]byte, error) {
s.RLock()
b, err := json.Marshal(jState(*s))
s.RUnlock()
return b, err
}
func wait(waitChan <-chan struct{}, timeout time.Duration) error {
if timeout < 0 {
<-waitChan
return nil
}
select {
case <-time.After(timeout):
return fmt.Errorf("Timed out: %v", timeout)
case <-waitChan:
return nil
}
}
// WaitRunning waits until state is running. If state already running it returns
// immediatly. If you want wait forever you must supply negative timeout.
// Returns pid, that was passed to SetRunning
func (s *State) WaitRunning(timeout time.Duration) (int, error) {
s.RLock()
if s.IsRunning() {
pid := s.Pid
s.RUnlock()
return pid, nil
}
waitChan := s.waitChan
s.RUnlock()
if err := wait(waitChan, timeout); err != nil {
return -1, err
}
return s.GetPid(), nil
}
// WaitStop waits until state is stopped. If state already stopped it returns
// immediatly. If you want wait forever you must supply negative timeout.
// Returns exit code, that was passed to SetStopped
func (s *State) WaitStop(timeout time.Duration) (int, error) {
s.RLock()
if !s.Running {
exitCode := s.ExitCode
s.RUnlock()
return exitCode, nil
}
waitChan := s.waitChan
s.RUnlock()
if err := wait(waitChan, timeout); err != nil {
return -1, err
}
return s.GetExitCode(), nil
}
func (s *State) IsRunning() bool {
s.RLock()
res := s.Running
s.RUnlock()
return res
}
func (s *State) GetPid() int {
s.RLock()
res := s.Pid
s.RUnlock()
return res
}
func (s *State) GetExitCode() int {
s.RLock()
res := s.ExitCode
s.RUnlock()
return res
}
func (s *State) SetRunning(pid int) {
s.Lock()
s.Running = true
s.Paused = false
s.Restarting = false
s.ExitCode = 0
s.Pid = pid
s.StartedAt = time.Now().UTC()
close(s.waitChan) // fire waiters for start
s.waitChan = make(chan struct{})
s.Unlock()
}
func (s *State) SetStopped(exitCode int) {
s.Lock()
s.Running = false
s.Restarting = false
s.Pid = 0
s.FinishedAt = time.Now().UTC()
s.ExitCode = exitCode
close(s.waitChan) // fire waiters for stop
s.waitChan = make(chan struct{})
s.Unlock()
}
// SetRestarting is when docker hanldes the auto restart of containers when they are
// in the middle of a stop and being restarted again
func (s *State) SetRestarting(exitCode int) {
s.Lock()
// we should consider the container running when it is restarting because of
// all the checks in docker around rm/stop/etc
s.Running = true
s.Restarting = true
s.Pid = 0
s.FinishedAt = time.Now().UTC()
s.ExitCode = exitCode
close(s.waitChan) // fire waiters for stop
s.waitChan = make(chan struct{})
s.Unlock()
}
func (s *State) IsRestarting() bool {
s.RLock()
res := s.Restarting
s.RUnlock()
return res
}
func (s *State) SetPaused() {
s.Lock()
s.Paused = true
s.Unlock()
}
func (s *State) SetUnpaused() {
s.Lock()
s.Paused = false
s.Unlock()
}
func (s *State) IsPaused() bool {
s.RLock()
res := s.Paused
s.RUnlock()
return res
}