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package daemon
import (
"context"
"fmt"
"io"
"github.com/containerd/log"
"github.com/docker/docker/api/types/events"
"github.com/docker/docker/container"
"github.com/docker/docker/errdefs"
"github.com/moby/go-archive"
"github.com/moby/go-archive/chrootarchive"
)
// 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(ctx context.Context, name string, out io.Writer) error {
ctr, err := daemon.GetContainer(name)
if err != nil {
return err
}
if isWindows && ctr.ImagePlatform.OS == "windows" {
return fmt.Errorf("the daemon on this operating system does not support exporting Windows containers")
}
if ctr.IsDead() {
err := fmt.Errorf("You cannot export container %s which is Dead", ctr.ID)
return errdefs.Conflict(err)
}
if ctr.IsRemovalInProgress() {
err := fmt.Errorf("You cannot export container %s which is being removed", ctr.ID)
return errdefs.Conflict(err)
}
err = daemon.containerExport(ctx, ctr, out)
if err != nil {
return fmt.Errorf("Error exporting container %s: %v", name, err)
}
return nil
}
func (daemon *Daemon) containerExport(ctx context.Context, ctr *container.Container, out io.Writer) error {
rwl := ctr.RWLayer
if rwl == nil {
return fmt.Errorf("container %s has no rootfs", ctr.ID)
}
if err := ctx.Err(); err != nil {
return err
}
basefs, err := rwl.Mount(ctr.GetMountLabel())
if err != nil {
return err
}
defer func() {
if err := rwl.Unmount(); err != nil {
log.G(ctx).WithFields(log.Fields{"error": err, "container": ctr.ID}).Warn("Failed to unmount container RWLayer after export")
}
}()
archv, err := chrootarchive.Tar(basefs, &archive.TarOptions{
Compression: archive.Uncompressed,
IDMap: daemon.idMapping,
}, basefs)
if err != nil {
return err
}
ctx, cancel := context.WithCancel(ctx)
defer cancel()
context.AfterFunc(ctx, func() {
_ = archv.Close()
})
// Stream the entire contents of the container (basically a volatile snapshot)
if _, err := io.Copy(out, archv); err != nil {
if err := ctx.Err(); err != nil {
return errdefs.Cancelled(err)
}
return err
}
daemon.LogContainerEvent(ctr, events.ActionExport)
return nil
}
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