mirror of https://github.com/k3s-io/k3s
125 lines
3.7 KiB
Go
125 lines
3.7 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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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 wsstream
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import (
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"encoding/base64"
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"io"
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"net/http"
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"time"
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"golang.org/x/net/websocket"
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"k8s.io/kubernetes/pkg/util/runtime"
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)
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// The WebSocket subprotocol "binary.k8s.io" will only send messages to the
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// client and ignore messages sent to the server. The received messages are
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// the exact bytes written to the stream. Zero byte messages are possible.
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const binaryWebSocketProtocol = "binary.k8s.io"
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// The WebSocket subprotocol "base64.binary.k8s.io" will only send messages to the
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// client and ignore messages sent to the server. The received messages are
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// a base64 version of the bytes written to the stream. Zero byte messages are
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// possible.
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const base64BinaryWebSocketProtocol = "base64.binary.k8s.io"
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// Reader supports returning an arbitrary byte stream over a websocket channel.
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// Supports the "binary.k8s.io" and "base64.binary.k8s.io" subprotocols.
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type Reader struct {
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err chan error
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r io.Reader
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ping bool
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timeout time.Duration
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}
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// NewReader creates a WebSocket pipe that will copy the contents of r to a provided
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// WebSocket connection. If ping is true, a zero length message will be sent to the client
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// before the stream begins reading.
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func NewReader(r io.Reader, ping bool) *Reader {
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return &Reader{
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r: r,
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err: make(chan error),
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ping: ping,
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}
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}
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// SetIdleTimeout sets the interval for both reads and writes before timeout. If not specified,
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// there is no timeout on the reader.
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func (r *Reader) SetIdleTimeout(duration time.Duration) {
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r.timeout = duration
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}
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func (r *Reader) handshake(config *websocket.Config, req *http.Request) error {
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return handshake(config, req, []string{binaryWebSocketProtocol, base64BinaryWebSocketProtocol})
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}
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// Copy the reader to the response. The created WebSocket is closed after this
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// method completes.
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func (r *Reader) Copy(w http.ResponseWriter, req *http.Request) error {
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go func() {
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defer runtime.HandleCrash()
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websocket.Server{Handshake: r.handshake, Handler: r.handle}.ServeHTTP(w, req)
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}()
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return <-r.err
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}
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// handle implements a WebSocket handler.
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func (r *Reader) handle(ws *websocket.Conn) {
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encode := len(ws.Config().Protocol) > 0 && ws.Config().Protocol[0] == base64BinaryWebSocketProtocol
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defer close(r.err)
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defer ws.Close()
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go IgnoreReceives(ws, r.timeout)
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r.err <- messageCopy(ws, r.r, encode, r.ping, r.timeout)
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}
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func resetTimeout(ws *websocket.Conn, timeout time.Duration) {
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if timeout > 0 {
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ws.SetDeadline(time.Now().Add(timeout))
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}
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}
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func messageCopy(ws *websocket.Conn, r io.Reader, base64Encode, ping bool, timeout time.Duration) error {
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buf := make([]byte, 2048)
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if ping {
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resetTimeout(ws, timeout)
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if err := websocket.Message.Send(ws, []byte{}); err != nil {
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return err
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}
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}
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for {
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resetTimeout(ws, timeout)
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n, err := r.Read(buf)
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if err != nil {
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if err == io.EOF {
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return nil
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}
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return err
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}
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if n > 0 {
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if base64Encode {
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if err := websocket.Message.Send(ws, base64.StdEncoding.EncodeToString(buf[:n])); err != nil {
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return err
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}
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} else {
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if err := websocket.Message.Send(ws, buf[:n]); err != nil {
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return err
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}
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}
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}
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}
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}
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