dotcloud/docker

package daemon // import "github.com/docker/docker/daemon"

import (
    "context"
    "fmt"

    "github.com/containerd/log"
    "github.com/docker/docker/api/types/events"
    "github.com/docker/docker/container"
)

// ContainerPause pauses a container
func (daemon *Daemon) ContainerPause(name string) error {
    ctr, err := daemon.GetContainer(name)
    if err != nil {
        return err
    }
    return daemon.containerPause(ctr)
}

// containerPause pauses the container execution without stopping the process.
// The execution can be resumed by calling containerUnpause.
func (daemon *Daemon) containerPause(container *container.Container) error {
    container.Lock()
    defer container.Unlock()

    // We cannot Pause the container which is not running
    tsk, err := container.GetRunningTask()
    if err != nil {
        return err
    }

    // We cannot Pause the container which is already paused
    if container.Paused {
        return errNotPaused(container.ID)
    }

    // We cannot Pause the container which is restarting
    if container.Restarting {
        return errContainerIsRestarting(container.ID)
    }

    if err := tsk.Pause(context.Background()); err != nil {
        return fmt.Errorf("cannot pause container %s: %s", container.ID, err)
    }

    container.Paused = true
    daemon.setStateCounter(container)
    daemon.updateHealthMonitor(container)
    daemon.LogContainerEvent(container, events.ActionPause)

    if err := container.CheckpointTo(context.WithoutCancel(context.TODO()), daemon.containersReplica); err != nil {
        log.G(context.TODO()).WithError(err).Warn("could not save container to disk")
    }

    return nil
}