package daemon // import "github.com/docker/docker/daemon" import ( "fmt" "io" "github.com/docker/docker/container" "github.com/docker/docker/errdefs" "github.com/docker/docker/pkg/archive" "github.com/docker/docker/pkg/ioutils" "github.com/docker/docker/pkg/system" ) // ContainerExport writes the contents of the container to the given // writer. An error is returned if the container cannot be found. func (daemon *Daemon) ContainerExport(name string, out io.Writer) error { container, err := daemon.GetContainer(name) if err != nil { return err } if isWindows && container.OS == "windows" { return fmt.Errorf("the daemon on this operating system does not support exporting Windows containers") } if container.IsDead() { err := fmt.Errorf("You cannot export container %s which is Dead", container.ID) return errdefs.Conflict(err) } if container.IsRemovalInProgress() { err := fmt.Errorf("You cannot export container %s which is being removed", container.ID) return errdefs.Conflict(err) } data, err := daemon.containerExport(container) if err != nil { return fmt.Errorf("Error exporting container %s: %v", name, err) } defer data.Close() // Stream the entire contents of the container (basically a volatile snapshot) if _, err := io.Copy(out, data); err != nil { return fmt.Errorf("Error exporting container %s: %v", name, err) } return nil } func (daemon *Daemon) containerExport(container *container.Container) (arch io.ReadCloser, err error) { if !system.IsOSSupported(container.OS) { return nil, fmt.Errorf("cannot export %s: %s ", container.ID, system.ErrNotSupportedOperatingSystem) } rwlayer, err := daemon.imageService.GetLayerByID(container.ID, container.OS) if err != nil { return nil, err } defer func() { if err != nil { daemon.imageService.ReleaseLayer(rwlayer, container.OS) } }() basefs, err := rwlayer.Mount(container.GetMountLabel()) if err != nil { return nil, err } archive, err := archivePath(basefs, basefs.Path(), &archive.TarOptions{ Compression: archive.Uncompressed, UIDMaps: daemon.idMapping.UIDs(), GIDMaps: daemon.idMapping.GIDs(), }, basefs.Path()) if err != nil { rwlayer.Unmount() return nil, err } arch = ioutils.NewReadCloserWrapper(archive, func() error { err := archive.Close() rwlayer.Unmount() daemon.imageService.ReleaseLayer(rwlayer, container.OS) return err }) daemon.LogContainerEvent(container, "export") return arch, err }