when a put request is retried due to the response from registry,
the body of the request should be seekable. A dynamic pipe is added
to the body so that the content of the body can be read again.
Currently a maximum of 5 resets are allowed, above which will fail the
request. A new error ErrReset is introduced which informs that a
reset has occured and request needs to be retried.
also added tests for Copy() and push() to test the new functionality
Signed-off-by: Akhil Mohan <makhil@vmware.com>
`dockerPusher` provides `pushWriter` which implements `content.Writer`.
However, even if `pushWriter` become abort status (i.e. `Close()` is called
before `Commit()`), `dockerPusher` doesn't recognise that status and treats that
writer as on-going.
This behaviour doesn't allow the client to retry an aborted push.
This commit fixes this issue.
This commit also adds an test to ensure that the issue is fixed.
Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
