moby/daemon/update.go
Cory Snider 0b592467d9 daemon: read-copy-update the daemon config
Ensure data-race-free access to the daemon configuration without
locking by mutating a deep copy of the config and atomically storing
a pointer to the copy into the daemon-wide configStore value. Any
operations which need to read from the daemon config must capture the
configStore value only once and pass it around to guarantee a consistent
view of the config.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2023-06-01 14:45:24 -04:00

106 lines
2.8 KiB
Go

package daemon // import "github.com/docker/docker/daemon"
import (
"context"
"fmt"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/errdefs"
"github.com/pkg/errors"
)
// ContainerUpdate updates configuration of the container
func (daemon *Daemon) ContainerUpdate(name string, hostConfig *container.HostConfig) (container.ContainerUpdateOKBody, error) {
var warnings []string
daemonCfg := daemon.config()
warnings, err := daemon.verifyContainerSettings(daemonCfg, hostConfig, nil, true)
if err != nil {
return container.ContainerUpdateOKBody{Warnings: warnings}, errdefs.InvalidParameter(err)
}
if err := daemon.update(name, hostConfig); err != nil {
return container.ContainerUpdateOKBody{Warnings: warnings}, err
}
return container.ContainerUpdateOKBody{Warnings: warnings}, nil
}
func (daemon *Daemon) update(name string, hostConfig *container.HostConfig) error {
if hostConfig == nil {
return nil
}
ctr, err := daemon.GetContainer(name)
if err != nil {
return err
}
restoreConfig := false
backupHostConfig := *ctr.HostConfig
defer func() {
if restoreConfig {
ctr.Lock()
if !ctr.RemovalInProgress && !ctr.Dead {
ctr.HostConfig = &backupHostConfig
ctr.CheckpointTo(daemon.containersReplica)
}
ctr.Unlock()
}
}()
ctr.Lock()
if ctr.RemovalInProgress || ctr.Dead {
ctr.Unlock()
return errCannotUpdate(ctr.ID, fmt.Errorf("container is marked for removal and cannot be \"update\""))
}
if err := ctr.UpdateContainer(hostConfig); err != nil {
restoreConfig = true
ctr.Unlock()
return errCannotUpdate(ctr.ID, err)
}
if err := ctr.CheckpointTo(daemon.containersReplica); err != nil {
restoreConfig = true
ctr.Unlock()
return errCannotUpdate(ctr.ID, err)
}
ctr.Unlock()
// if Restart Policy changed, we need to update container monitor
if hostConfig.RestartPolicy.Name != "" {
ctr.UpdateMonitor(hostConfig.RestartPolicy)
}
defer daemon.LogContainerEvent(ctr, "update")
// If container is not running, update hostConfig struct is enough,
// resources will be updated when the container is started again.
// If container is running (including paused), we need to update configs
// to the real world.
ctr.Lock()
isRestarting := ctr.Restarting
tsk, err := ctr.GetRunningTask()
ctr.Unlock()
if errdefs.IsConflict(err) || isRestarting {
return nil
}
if err != nil {
return err
}
if err := tsk.UpdateResources(context.TODO(), toContainerdResources(hostConfig.Resources)); err != nil {
restoreConfig = true
// TODO: it would be nice if containerd responded with better errors here so we can classify this better.
return errCannotUpdate(ctr.ID, errdefs.System(err))
}
return nil
}
func errCannotUpdate(containerID string, err error) error {
return errors.Wrap(err, "Cannot update container "+containerID)
}