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package restartmanager // import "github.com/docker/docker/restartmanager"
import (
"errors"
"fmt"
"sync"
"time"
"github.com/docker/docker/api/types/container"
)
const (
backoffMultiplier = 2
defaultTimeout = 100 * time.Millisecond
maxRestartTimeout = 1 * time.Minute
)
// ErrRestartCanceled is returned when the restart manager has been
// canceled and will no longer restart the container.
var ErrRestartCanceled = errors.New("restart canceled")
// RestartManager defines object that controls container restarting rules.
type RestartManager interface {
Cancel() error
ShouldRestart(exitCode uint32, hasBeenManuallyStopped bool, executionDuration time.Duration) (bool, chan error, error)
}
type restartManager struct {
sync.Mutex
sync.Once
policy container.RestartPolicy
restartCount int
timeout time.Duration
active bool
cancel chan struct{}
canceled bool
}
// New returns a new restartManager based on a policy.
func New(policy container.RestartPolicy, restartCount int) RestartManager {
return &restartManager{policy: policy, restartCount: restartCount, cancel: make(chan struct{})}
}
func (rm *restartManager) SetPolicy(policy container.RestartPolicy) {
rm.Lock()
rm.policy = policy
rm.Unlock()
}
func (rm *restartManager) ShouldRestart(exitCode uint32, hasBeenManuallyStopped bool, executionDuration time.Duration) (bool, chan error, error) {
if rm.policy.IsNone() {
return false, nil, nil
}
rm.Lock()
unlockOnExit := true
defer func() {
if unlockOnExit {
rm.Unlock()
}
}()
if rm.canceled {
return false, nil, ErrRestartCanceled
}
if rm.active {
return false, nil, fmt.Errorf("invalid call on an active restart manager")
}
// if the container ran for more than 10s, regardless of status and policy reset the
// the timeout back to the default.
if executionDuration.Seconds() >= 10 {
rm.timeout = 0
}
switch {
case rm.timeout == 0:
rm.timeout = defaultTimeout
case rm.timeout < maxRestartTimeout:
rm.timeout *= backoffMultiplier
}
if rm.timeout > maxRestartTimeout {
rm.timeout = maxRestartTimeout
}
var restart bool
switch {
case rm.policy.IsAlways():
restart = true
case rm.policy.IsUnlessStopped() && !hasBeenManuallyStopped:
restart = true
case rm.policy.IsOnFailure():
// the default value of 0 for MaximumRetryCount means that we will not enforce a maximum count
if max := rm.policy.MaximumRetryCount; max == 0 || rm.restartCount < max {
restart = exitCode != 0
}
}
if !restart {
rm.active = false
return false, nil, nil
}
rm.restartCount++
unlockOnExit = false
rm.active = true
rm.Unlock()
ch := make(chan error)
go func() {
timeout := time.NewTimer(rm.timeout)
defer timeout.Stop()
select {
case <-rm.cancel:
ch <- ErrRestartCanceled
close(ch)
case <-timeout.C:
rm.Lock()
close(ch)
rm.active = false
rm.Unlock()
}
}()
return true, ch, nil
}
func (rm *restartManager) Cancel() error {
rm.Do(func() {
rm.Lock()
rm.canceled = true
close(rm.cancel)
rm.Unlock()
})
return nil
}
|
