WebSocket Client and V5 RemoteCommand Subprotocol

Kubernetes-commit: a0d6a815fcc02cbfea1bb22d13a8e896ecbe116c

tools/remotecommand/spdy.go

@@ -0,0 +1,150 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package remotecommand
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"k8s.io/apimachinery/pkg/util/httpstream"
+	"k8s.io/apimachinery/pkg/util/remotecommand"
+	restclient "k8s.io/client-go/rest"
+	"k8s.io/client-go/transport/spdy"
+	"k8s.io/klog/v2"
+)
+
+// spdyStreamExecutor handles transporting standard shell streams over an httpstream connection.
+type spdyStreamExecutor struct {
+	upgrader  spdy.Upgrader
+	transport http.RoundTripper
+
+	method    string
+	url       *url.URL
+	protocols []string
+}
+
+// NewSPDYExecutor connects to the provided server and upgrades the connection to
+// multiplexed bidirectional streams.
+func NewSPDYExecutor(config *restclient.Config, method string, url *url.URL) (Executor, error) {
+	wrapper, upgradeRoundTripper, err := spdy.RoundTripperFor(config)
+	if err != nil {
+		return nil, err
+	}
+	return NewSPDYExecutorForTransports(wrapper, upgradeRoundTripper, method, url)
+}
+
+// NewSPDYExecutorForTransports connects to the provided server using the given transport,
+// upgrades the response using the given upgrader to multiplexed bidirectional streams.
+func NewSPDYExecutorForTransports(transport http.RoundTripper, upgrader spdy.Upgrader, method string, url *url.URL) (Executor, error) {
+	return NewSPDYExecutorForProtocols(
+		transport, upgrader, method, url,
+		remotecommand.StreamProtocolV5Name,
+		remotecommand.StreamProtocolV4Name,
+		remotecommand.StreamProtocolV3Name,
+		remotecommand.StreamProtocolV2Name,
+		remotecommand.StreamProtocolV1Name,
+	)
+}
+
+// NewSPDYExecutorForProtocols connects to the provided server and upgrades the connection to
+// multiplexed bidirectional streams using only the provided protocols. Exposed for testing, most
+// callers should use NewSPDYExecutor or NewSPDYExecutorForTransports.
+func NewSPDYExecutorForProtocols(transport http.RoundTripper, upgrader spdy.Upgrader, method string, url *url.URL, protocols ...string) (Executor, error) {
+	return &spdyStreamExecutor{
+		upgrader:  upgrader,
+		transport: transport,
+		method:    method,
+		url:       url,
+		protocols: protocols,
+	}, nil
+}
+
+// Stream opens a protocol streamer to the server and streams until a client closes
+// the connection or the server disconnects.
+func (e *spdyStreamExecutor) Stream(options StreamOptions) error {
+	return e.StreamWithContext(context.Background(), options)
+}
+
+// newConnectionAndStream creates a new SPDY connection and a stream protocol handler upon it.
+func (e *spdyStreamExecutor) newConnectionAndStream(ctx context.Context, options StreamOptions) (httpstream.Connection, streamProtocolHandler, error) {
+	req, err := http.NewRequestWithContext(ctx, e.method, e.url.String(), nil)
+	if err != nil {
+		return nil, nil, fmt.Errorf("error creating request: %v", err)
+	}
+
+	conn, protocol, err := spdy.Negotiate(
+		e.upgrader,
+		&http.Client{Transport: e.transport},
+		req,
+		e.protocols...,
+	)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var streamer streamProtocolHandler
+
+	switch protocol {
+	case remotecommand.StreamProtocolV5Name:
+		streamer = newStreamProtocolV5(options)
+	case remotecommand.StreamProtocolV4Name:
+		streamer = newStreamProtocolV4(options)
+	case remotecommand.StreamProtocolV3Name:
+		streamer = newStreamProtocolV3(options)
+	case remotecommand.StreamProtocolV2Name:
+		streamer = newStreamProtocolV2(options)
+	case "":
+		klog.V(4).Infof("The server did not negotiate a streaming protocol version. Falling back to %s", remotecommand.StreamProtocolV1Name)
+		fallthrough
+	case remotecommand.StreamProtocolV1Name:
+		streamer = newStreamProtocolV1(options)
+	}
+
+	return conn, streamer, nil
+}
+
+// StreamWithContext opens a protocol streamer to the server and streams until a client closes
+// the connection or the server disconnects or the context is done.
+func (e *spdyStreamExecutor) StreamWithContext(ctx context.Context, options StreamOptions) error {
+	conn, streamer, err := e.newConnectionAndStream(ctx, options)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	panicChan := make(chan any, 1)
+	errorChan := make(chan error, 1)
+	go func() {
+		defer func() {
+			if p := recover(); p != nil {
+				panicChan <- p
+			}
+		}()
+		errorChan <- streamer.stream(conn)
+	}()
+
+	select {
+	case p := <-panicChan:
+		panic(p)
+	case err := <-errorChan:
+		return err
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}