diff options
Diffstat (limited to 'vendor/k8s.io/apiserver/pkg/util/wsstream/stream.go')
-rw-r--r-- | vendor/k8s.io/apiserver/pkg/util/wsstream/stream.go | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/vendor/k8s.io/apiserver/pkg/util/wsstream/stream.go b/vendor/k8s.io/apiserver/pkg/util/wsstream/stream.go new file mode 100644 index 000000000..9dd165bfa --- /dev/null +++ b/vendor/k8s.io/apiserver/pkg/util/wsstream/stream.go @@ -0,0 +1,177 @@ +/* +Copyright 2015 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 wsstream + +import ( + "encoding/base64" + "io" + "net/http" + "sync" + "time" + + "golang.org/x/net/websocket" + + "k8s.io/apimachinery/pkg/util/runtime" +) + +// The WebSocket subprotocol "binary.k8s.io" will only send messages to the +// client and ignore messages sent to the server. The received messages are +// the exact bytes written to the stream. Zero byte messages are possible. +const binaryWebSocketProtocol = "binary.k8s.io" + +// The WebSocket subprotocol "base64.binary.k8s.io" will only send messages to the +// client and ignore messages sent to the server. The received messages are +// a base64 version of the bytes written to the stream. Zero byte messages are +// possible. +const base64BinaryWebSocketProtocol = "base64.binary.k8s.io" + +// ReaderProtocolConfig describes a websocket subprotocol with one stream. +type ReaderProtocolConfig struct { + Binary bool +} + +// NewDefaultReaderProtocols returns a stream protocol map with the +// subprotocols "", "channel.k8s.io", "base64.channel.k8s.io". +func NewDefaultReaderProtocols() map[string]ReaderProtocolConfig { + return map[string]ReaderProtocolConfig{ + "": {Binary: true}, + binaryWebSocketProtocol: {Binary: true}, + base64BinaryWebSocketProtocol: {Binary: false}, + } +} + +// Reader supports returning an arbitrary byte stream over a websocket channel. +type Reader struct { + err chan error + r io.Reader + ping bool + timeout time.Duration + protocols map[string]ReaderProtocolConfig + selectedProtocol string + + handleCrash func() // overridable for testing +} + +// NewReader creates a WebSocket pipe that will copy the contents of r to a provided +// WebSocket connection. If ping is true, a zero length message will be sent to the client +// before the stream begins reading. +// +// The protocols parameter maps subprotocol names to StreamProtocols. The empty string +// subprotocol name is used if websocket.Config.Protocol is empty. +func NewReader(r io.Reader, ping bool, protocols map[string]ReaderProtocolConfig) *Reader { + return &Reader{ + r: r, + err: make(chan error), + ping: ping, + protocols: protocols, + handleCrash: func() { runtime.HandleCrash() }, + } +} + +// SetIdleTimeout sets the interval for both reads and writes before timeout. If not specified, +// there is no timeout on the reader. +func (r *Reader) SetIdleTimeout(duration time.Duration) { + r.timeout = duration +} + +func (r *Reader) handshake(config *websocket.Config, req *http.Request) error { + supportedProtocols := make([]string, 0, len(r.protocols)) + for p := range r.protocols { + supportedProtocols = append(supportedProtocols, p) + } + return handshake(config, req, supportedProtocols) +} + +// Copy the reader to the response. The created WebSocket is closed after this +// method completes. +func (r *Reader) Copy(w http.ResponseWriter, req *http.Request) error { + go func() { + defer r.handleCrash() + websocket.Server{Handshake: r.handshake, Handler: r.handle}.ServeHTTP(w, req) + }() + return <-r.err +} + +// handle implements a WebSocket handler. +func (r *Reader) handle(ws *websocket.Conn) { + // Close the connection when the client requests it, or when we finish streaming, whichever happens first + closeConnOnce := &sync.Once{} + closeConn := func() { + closeConnOnce.Do(func() { + ws.Close() + }) + } + + negotiated := ws.Config().Protocol + r.selectedProtocol = negotiated[0] + defer close(r.err) + defer closeConn() + + go func() { + defer runtime.HandleCrash() + // This blocks until the connection is closed. + // Client should not send anything. + IgnoreReceives(ws, r.timeout) + // Once the client closes, we should also close + closeConn() + }() + + r.err <- messageCopy(ws, r.r, !r.protocols[r.selectedProtocol].Binary, r.ping, r.timeout) +} + +func resetTimeout(ws *websocket.Conn, timeout time.Duration) { + if timeout > 0 { + ws.SetDeadline(time.Now().Add(timeout)) + } +} + +func messageCopy(ws *websocket.Conn, r io.Reader, base64Encode, ping bool, timeout time.Duration) error { + buf := make([]byte, 2048) + if ping { + resetTimeout(ws, timeout) + if base64Encode { + if err := websocket.Message.Send(ws, ""); err != nil { + return err + } + } else { + if err := websocket.Message.Send(ws, []byte{}); err != nil { + return err + } + } + } + for { + resetTimeout(ws, timeout) + n, err := r.Read(buf) + if err != nil { + if err == io.EOF { + return nil + } + return err + } + if n > 0 { + if base64Encode { + if err := websocket.Message.Send(ws, base64.StdEncoding.EncodeToString(buf[:n])); err != nil { + return err + } + } else { + if err := websocket.Message.Send(ws, buf[:n]); err != nil { + return err + } + } + } + } +} |