Decouple daemon and container to export containers.

Signed-off-by: David Calavera <david.calavera@gmail.com>

daemon/container.go

@@ -356,30 +356,6 @@ func (container *Container) Resize(h, w int) error {
 	return nil
 }
 
-func (container *Container) export() (archive.Archive, error) {
-	if err := container.Mount(); err != nil {
-		return nil, err
-	}
-
-	uidMaps, gidMaps := container.daemon.GetUIDGIDMaps()
-	archive, err := archive.TarWithOptions(container.basefs, &archive.TarOptions{
-		Compression: archive.Uncompressed,
-		UIDMaps:     uidMaps,
-		GIDMaps:     gidMaps,
-	})
-	if err != nil {
-		container.Unmount()
-		return nil, err
-	}
-	arch := ioutils.NewReadCloserWrapper(archive, func() error {
-		err := archive.Close()
-		container.Unmount()
-		return err
-	})
-	container.logEvent("export")
-	return arch, err
-}
-
 // Mount sets container.basefs
 func (container *Container) Mount() error {
 	return container.daemon.Mount(container)

daemon/export.go

@@ -4,6 +4,8 @@ import (
 	"io"
 
 	derr "github.com/docker/docker/errors"
+	"github.com/docker/docker/pkg/archive"
+	"github.com/docker/docker/pkg/ioutils"
 )
 
 // ContainerExport writes the contents of the container to the given
@@ -14,7 +16,7 @@ func (daemon *Daemon) ContainerExport(name string, out io.Writer) error {
 		return err
 	}
 
-	data, err := container.export()
+	data, err := daemon.containerExport(container)
 	if err != nil {
 		return derr.ErrorCodeExportFailed.WithArgs(name, err)
 	}
@@ -26,3 +28,27 @@ func (daemon *Daemon) ContainerExport(name string, out io.Writer) error {
 	}
 	return nil
 }
+
+func (daemon *Daemon) containerExport(container *Container) (archive.Archive, error) {
+	if err := daemon.Mount(container); err != nil {
+		return nil, err
+	}
+
+	uidMaps, gidMaps := daemon.GetUIDGIDMaps()
+	archive, err := archive.TarWithOptions(container.basefs, &archive.TarOptions{
+		Compression: archive.Uncompressed,
+		UIDMaps:     uidMaps,
+		GIDMaps:     gidMaps,
+	})
+	if err != nil {
+		daemon.unmount(container)
+		return nil, err
+	}
+	arch := ioutils.NewReadCloserWrapper(archive, func() error {
+		err := archive.Close()
+		container.Unmount()
+		return err
+	})
+	daemon.logContainerEvent(container, "export")
+	return arch, err
+}