Refactor Kubelet's server functionality into a server package. Most
notably, move pkg/kubelet/server.go into
pkg/kubelet/server/server.go. This will lead to better separation of
concerns and a more readable code hierarchy.
TestPortForward was failing occasionally due to the way the test was
written. It created a port forwarding session, then connected a client
to the local port, attempted to send some data, attempted to receive
some data, and then tore down the port forwarding session.
Unfortunately, some times the attempt to send data from the client to
the remote would be enqueued but not processed by the time the test tore
down everything. As a result, the data stream could get closed before
the client's data was transmitted to the server. If this happened, you'd
see an error such as 'forward 2 ports with bidirectional data: server
expected to receive "ghij", got "" for port 6000'.
This fixes the test by serializing the data flow: the client writes to
the remote, the remote waits to receive that data, the remote writes to
the client, and the client waits to receive the data from the remote.
This all takes place prior to the test tearing down port forwarding.
Move port forward protocol name constant to a subpackage underneath
pkg/kubelet to avoid flags applicable to the kubelet leaking into
kubectl. Eventually, handlers for specific protocol versions will move
into the new subpackage as well.
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
Correct port-forward data copying logic so that the server closes its
half of the data stream when socat exits, and the client closes its half
of the data stream when it finishes writing.
Modify the client to wait for both copies (client->server,
server->client) to finish before it unblocks.
Fix race condition in the Kubelet's handling of incoming port forward
streams. Have the client generate a connectionID header to be used to
associate the error and data streams for a single connection, instead of
assuming that streams n and n+1 go together. Attempt to generate a
pseudo connectionID in the server in the event the connectionID header
isn't present (older clients); this is a best-effort approach that only
really works with 1 connection at a time, whereas multiple concurrent
connections will only work reliably with a newer client that is
generating connectionID.
Davanum Srinivas