To support resumable download, the fetcher for a remote must implement
`io.Seeker`. If implemented the `content.Copy` function will detect the
seeker and begin from where the download was terminated by a previous
attempt.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Add support for downloading layers with external URLs and
foreign/non-distributable mediatypes. This ensures that encountered
windows images are downloaded correctly. We still need to filter out the
extra windows resources when pulling linux, but this is a step towards
correctly supporting multi-platform images.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
Split resolver to only return a name with separate methods
for getting a fetcher and pusher. Add implementation for
push.
Signed-off-by: Derek McGowan <derek@mcgstyle.net>
