132 lines
4 KiB
Go
132 lines
4 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package remotecommand
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import (
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"fmt"
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"net/http"
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"time"
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"k8s.io/apimachinery/pkg/util/runtime"
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"k8s.io/apiserver/pkg/server/httplog"
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"k8s.io/apiserver/pkg/util/wsstream"
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)
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const (
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stdinChannel = iota
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stdoutChannel
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stderrChannel
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errorChannel
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resizeChannel
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preV4BinaryWebsocketProtocol = wsstream.ChannelWebSocketProtocol
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preV4Base64WebsocketProtocol = wsstream.Base64ChannelWebSocketProtocol
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v4BinaryWebsocketProtocol = "v4." + wsstream.ChannelWebSocketProtocol
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v4Base64WebsocketProtocol = "v4." + wsstream.Base64ChannelWebSocketProtocol
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)
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// createChannels returns the standard channel types for a shell connection (STDIN 0, STDOUT 1, STDERR 2)
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// along with the approximate duplex value. It also creates the error (3) and resize (4) channels.
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func createChannels(opts *Options) []wsstream.ChannelType {
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// open the requested channels, and always open the error channel
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channels := make([]wsstream.ChannelType, 5)
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channels[stdinChannel] = readChannel(opts.Stdin)
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channels[stdoutChannel] = writeChannel(opts.Stdout)
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channels[stderrChannel] = writeChannel(opts.Stderr)
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channels[errorChannel] = wsstream.WriteChannel
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channels[resizeChannel] = wsstream.ReadChannel
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return channels
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}
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// readChannel returns wsstream.ReadChannel if real is true, or wsstream.IgnoreChannel.
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func readChannel(real bool) wsstream.ChannelType {
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if real {
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return wsstream.ReadChannel
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}
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return wsstream.IgnoreChannel
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}
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// writeChannel returns wsstream.WriteChannel if real is true, or wsstream.IgnoreChannel.
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func writeChannel(real bool) wsstream.ChannelType {
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if real {
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return wsstream.WriteChannel
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}
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return wsstream.IgnoreChannel
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}
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// createWebSocketStreams returns a context containing the websocket connection and
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// streams needed to perform an exec or an attach.
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func createWebSocketStreams(req *http.Request, w http.ResponseWriter, opts *Options, idleTimeout time.Duration) (*context, bool) {
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channels := createChannels(opts)
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conn := wsstream.NewConn(map[string]wsstream.ChannelProtocolConfig{
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"": {
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Binary: true,
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Channels: channels,
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},
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preV4BinaryWebsocketProtocol: {
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Binary: true,
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Channels: channels,
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},
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preV4Base64WebsocketProtocol: {
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Binary: false,
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Channels: channels,
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},
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v4BinaryWebsocketProtocol: {
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Binary: true,
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Channels: channels,
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},
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v4Base64WebsocketProtocol: {
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Binary: false,
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Channels: channels,
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},
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})
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conn.SetIdleTimeout(idleTimeout)
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negotiatedProtocol, streams, err := conn.Open(httplog.Unlogged(w), req)
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if err != nil {
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runtime.HandleError(fmt.Errorf("Unable to upgrade websocket connection: %v", err))
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return nil, false
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}
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// Send an empty message to the lowest writable channel to notify the client the connection is established
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// TODO: make generic to SPDY and WebSockets and do it outside of this method?
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switch {
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case opts.Stdout:
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streams[stdoutChannel].Write([]byte{})
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case opts.Stderr:
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streams[stderrChannel].Write([]byte{})
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default:
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streams[errorChannel].Write([]byte{})
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}
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ctx := &context{
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conn: conn,
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stdinStream: streams[stdinChannel],
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stdoutStream: streams[stdoutChannel],
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stderrStream: streams[stderrChannel],
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tty: opts.TTY,
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resizeStream: streams[resizeChannel],
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}
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switch negotiatedProtocol {
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case v4BinaryWebsocketProtocol, v4Base64WebsocketProtocol:
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ctx.writeStatus = v4WriteStatusFunc(streams[errorChannel])
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default:
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ctx.writeStatus = v1WriteStatusFunc(streams[errorChannel])
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}
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return ctx, true
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}
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