When kubectl starts an interactive attach session, it sends 2 resize
messages in quick succession. It seems that particularly in HTTP mode,
we often receive both of these WebSocket frames from the underlying
connection in a single read. However, our parser currently assumes 0-1
frames per read, and leaves the second frame in the read buffer until
the next read from the underlying connection. It doesn't take long after
that before we end up failing to skip a control message as we normally
should, and then we parse a control message as though it will have a
stream ID (part of the Kubernetes protocol) and error out.
Instead, we should keep parsing frames from the read buffer for as long
as we're able to parse complete frames, so this commit refactors the
messages parsing logic into a loop based on the contents of the read
buffer being non-empty.
k/k staging/src/k8s.io/kubectl/pkg/cmd/attach/attach.go for full
details of the resize messages.
There are at least a couple more multiple-frame read edge cases we
should handle, but this commit is very conservatively fixing a single
observed issue to make it a low-risk candidate for cherry picking.
Updates #13358
Change-Id: Iafb91ad1cbeed9c5231a1525d4563164fc1f002f
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>
Tom Proctor
02084629e2