Add streaming subprotocol negotiation for exec, attach, and port
forwarding. Restore previous (buggy) exec functionality as an
unspecified/unversioned subprotocol so newer kubectl clients can work
against 1.0.x kubelets.
The current executor structure is too dependent on client.Request
and client.Config. In order to do an attach from the server, it needs
to be possible to create an Executor from crypto/tls#TLSConfig and to
bypassing having a client.Request.
Changes:
* remotecommand.spdyExecutor - handles upgrading a request to SPDY and getting a connection
* remotecommand.NewAttach / New - moved to exec / portforward / attach since they handle requests
* Remove request.Upgrade() - it's too coupled to SPDY, and can live with the spdyExecutor
* Add request.VersionedParams(runtime.Object, runtime.ObjectConvertor) to handle object -> query transform
If stdin is noninteractive, the io.Copy from stdin to remoteStdin will
unblock when it finishes reading from stdin. In this case, make sure to
close remoteStdin so the server knows the client won't be sending any
more data. This ensures that the remote process terminates. For example:
echo foo | kubectl exec -i <pod> -- cat
Without this change, the `cat` process never terminates and `kubectl
exec` hangs.
Fix interactive exec sessions hanging after you type 'exit'.
Add e2e test to cover noninteractive stdin: `echo a | kubectl exec -i <pod>
cat`
Add e2e test to cover psuedo-interactive stdin: `kubectl exec -i <pod> bash`
Prep for sending multiple data frames over multiple streams in remote command
test, which is more likely to find flakes (requires bump of spdystream
once an issue with the frame worker queues not being fully drained when
a goaway frame is received).
