Prepared Messages (#211)

This commit is contained in:
Gary Burd 2017-02-14 09:41:18 -08:00 committed by GitHub
parent 9bc973af06
commit 804cb600d0
6 changed files with 357 additions and 7 deletions

23
conn.go
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@ -659,12 +659,33 @@ func (w *messageWriter) Close() error {
return nil return nil
} }
// WritePreparedMessage writes prepared message into connection.
func (c *Conn) WritePreparedMessage(pm *PreparedMessage) error {
frameType, frameData, err := pm.frame(prepareKey{
isServer: c.isServer,
compress: c.newCompressionWriter != nil && c.enableWriteCompression && isData(pm.messageType),
compressionLevel: c.compressionLevel,
})
if err != nil {
return err
}
if c.isWriting {
panic("concurrent write to websocket connection")
}
c.isWriting = true
err = c.write(frameType, c.writeDeadline, frameData, nil)
if !c.isWriting {
panic("concurrent write to websocket connection")
}
c.isWriting = false
return err
}
// WriteMessage is a helper method for getting a writer using NextWriter, // WriteMessage is a helper method for getting a writer using NextWriter,
// writing the message and closing the writer. // writing the message and closing the writer.
func (c *Conn) WriteMessage(messageType int, data []byte) error { func (c *Conn) WriteMessage(messageType int, data []byte) error {
if c.isServer && (c.newCompressionWriter == nil || !c.enableWriteCompression) { if c.isServer && (c.newCompressionWriter == nil || !c.enableWriteCompression) {
// Fast path with no allocations and single frame. // Fast path with no allocations and single frame.
if err := c.prepWrite(messageType); err != nil { if err := c.prepWrite(messageType); err != nil {

134
conn_broadcast_test.go Normal file
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@ -0,0 +1,134 @@
// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build go1.7
package websocket
import (
"io"
"io/ioutil"
"sync/atomic"
"testing"
)
// broadcastBench allows to run broadcast benchmarks.
// In every broadcast benchmark we create many connections, then send the same
// message into every connection and wait for all writes complete. This emulates
// an application where many connections listen to the same data - i.e. PUB/SUB
// scenarios with many subscribers in one channel.
type broadcastBench struct {
w io.Writer
message *broadcastMessage
closeCh chan struct{}
doneCh chan struct{}
count int32
conns []*broadcastConn
compression bool
usePrepared bool
}
type broadcastMessage struct {
payload []byte
prepared *PreparedMessage
}
type broadcastConn struct {
conn *Conn
msgCh chan *broadcastMessage
}
func newBroadcastConn(c *Conn) *broadcastConn {
return &broadcastConn{
conn: c,
msgCh: make(chan *broadcastMessage, 1),
}
}
func newBroadcastBench(usePrepared, compression bool) *broadcastBench {
bench := &broadcastBench{
w: ioutil.Discard,
doneCh: make(chan struct{}),
closeCh: make(chan struct{}),
usePrepared: usePrepared,
compression: compression,
}
msg := &broadcastMessage{
payload: textMessages(1)[0],
}
if usePrepared {
pm, _ := NewPreparedMessage(TextMessage, msg.payload)
msg.prepared = pm
}
bench.message = msg
bench.makeConns(10000)
return bench
}
func (b *broadcastBench) makeConns(numConns int) {
conns := make([]*broadcastConn, numConns)
for i := 0; i < numConns; i++ {
c := newConn(fakeNetConn{Reader: nil, Writer: b.w}, true, 1024, 1024)
if b.compression {
c.enableWriteCompression = true
c.newCompressionWriter = compressNoContextTakeover
}
conns[i] = newBroadcastConn(c)
go func(c *broadcastConn) {
for {
select {
case msg := <-c.msgCh:
if b.usePrepared {
c.conn.WritePreparedMessage(msg.prepared)
} else {
c.conn.WriteMessage(TextMessage, msg.payload)
}
val := atomic.AddInt32(&b.count, 1)
if val%int32(numConns) == 0 {
b.doneCh <- struct{}{}
}
case <-b.closeCh:
return
}
}
}(conns[i])
}
b.conns = conns
}
func (b *broadcastBench) close() {
close(b.closeCh)
}
func (b *broadcastBench) runOnce() {
for _, c := range b.conns {
c.msgCh <- b.message
}
<-b.doneCh
}
func BenchmarkBroadcast(b *testing.B) {
benchmarks := []struct {
name string
usePrepared bool
compression bool
}{
{"NoCompression", false, false},
{"WithCompression", false, true},
{"NoCompressionPrepared", true, false},
{"WithCompressionPrepared", true, true},
}
for _, bm := range benchmarks {
b.Run(bm.name, func(b *testing.B) {
bench := newBroadcastBench(bm.usePrepared, bm.compression)
defer bench.close()
b.ResetTimer()
for i := 0; i < b.N; i++ {
bench.runOnce()
}
b.ReportAllocs()
})
}
}

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@ -4,6 +4,7 @@
"outdir": "./reports/clients", "outdir": "./reports/clients",
"servers": [ "servers": [
{"agent": "ReadAllWriteMessage", "url": "ws://localhost:9000/m", "options": {"version": 18}}, {"agent": "ReadAllWriteMessage", "url": "ws://localhost:9000/m", "options": {"version": 18}},
{"agent": "ReadAllWritePreparedMessage", "url": "ws://localhost:9000/p", "options": {"version": 18}},
{"agent": "ReadAllWrite", "url": "ws://localhost:9000/r", "options": {"version": 18}}, {"agent": "ReadAllWrite", "url": "ws://localhost:9000/r", "options": {"version": 18}},
{"agent": "CopyFull", "url": "ws://localhost:9000/f", "options": {"version": 18}}, {"agent": "CopyFull", "url": "ws://localhost:9000/f", "options": {"version": 18}},
{"agent": "CopyWriterOnly", "url": "ws://localhost:9000/c", "options": {"version": 18}} {"agent": "CopyWriterOnly", "url": "ws://localhost:9000/c", "options": {"version": 18}}

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@ -85,7 +85,7 @@ func echoCopyFull(w http.ResponseWriter, r *http.Request) {
// echoReadAll echoes messages from the client by reading the entire message // echoReadAll echoes messages from the client by reading the entire message
// with ioutil.ReadAll. // with ioutil.ReadAll.
func echoReadAll(w http.ResponseWriter, r *http.Request, writeMessage bool) { func echoReadAll(w http.ResponseWriter, r *http.Request, writeMessage, writePrepared bool) {
conn, err := upgrader.Upgrade(w, r, nil) conn, err := upgrader.Upgrade(w, r, nil)
if err != nil { if err != nil {
log.Println("Upgrade:", err) log.Println("Upgrade:", err)
@ -109,10 +109,22 @@ func echoReadAll(w http.ResponseWriter, r *http.Request, writeMessage bool) {
} }
} }
if writeMessage { if writeMessage {
if !writePrepared {
err = conn.WriteMessage(mt, b) err = conn.WriteMessage(mt, b)
if err != nil { if err != nil {
log.Println("WriteMessage:", err) log.Println("WriteMessage:", err)
} }
} else {
pm, err := websocket.NewPreparedMessage(mt, b)
if err != nil {
log.Println("NewPreparedMessage:", err)
return
}
err = conn.WritePreparedMessage(pm)
if err != nil {
log.Println("WritePreparedMessage:", err)
}
}
} else { } else {
w, err := conn.NextWriter(mt) w, err := conn.NextWriter(mt)
if err != nil { if err != nil {
@ -132,11 +144,15 @@ func echoReadAll(w http.ResponseWriter, r *http.Request, writeMessage bool) {
} }
func echoReadAllWriter(w http.ResponseWriter, r *http.Request) { func echoReadAllWriter(w http.ResponseWriter, r *http.Request) {
echoReadAll(w, r, false) echoReadAll(w, r, false, false)
} }
func echoReadAllWriteMessage(w http.ResponseWriter, r *http.Request) { func echoReadAllWriteMessage(w http.ResponseWriter, r *http.Request) {
echoReadAll(w, r, true) echoReadAll(w, r, true, false)
}
func echoReadAllWritePreparedMessage(w http.ResponseWriter, r *http.Request) {
echoReadAll(w, r, true, true)
} }
func serveHome(w http.ResponseWriter, r *http.Request) { func serveHome(w http.ResponseWriter, r *http.Request) {
@ -161,6 +177,7 @@ func main() {
http.HandleFunc("/f", echoCopyFull) http.HandleFunc("/f", echoCopyFull)
http.HandleFunc("/r", echoReadAllWriter) http.HandleFunc("/r", echoReadAllWriter)
http.HandleFunc("/m", echoReadAllWriteMessage) http.HandleFunc("/m", echoReadAllWriteMessage)
http.HandleFunc("/p", echoReadAllWritePreparedMessage)
err := http.ListenAndServe(*addr, nil) err := http.ListenAndServe(*addr, nil)
if err != nil { if err != nil {
log.Fatal("ListenAndServe: ", err) log.Fatal("ListenAndServe: ", err)

103
prepared.go Normal file
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@ -0,0 +1,103 @@
// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package websocket
import (
"bytes"
"net"
"sync"
"time"
)
// PreparedMessage caches on the wire representations of a message payload.
// Use PreparedMessage to efficiently send a message payload to multiple
// connections. PreparedMessage is especially useful when compression is used
// because the CPU and memory expensive compression operation can be executed
// once for a given set of compression options.
type PreparedMessage struct {
messageType int
data []byte
err error
mu sync.Mutex
frames map[prepareKey]*preparedFrame
}
// prepareKey defines a unique set of options to cache prepared frames in PreparedMessage.
type prepareKey struct {
isServer bool
compress bool
compressionLevel int
}
// preparedFrame contains data in wire representation.
type preparedFrame struct {
once sync.Once
data []byte
}
// NewPreparedMessage returns an initialized PreparedMessage. You can then send
// it to connection using WritePreparedMessage method. Valid wire
// representation will be calculated lazily only once for a set of current
// connection options.
func NewPreparedMessage(messageType int, data []byte) (*PreparedMessage, error) {
pm := &PreparedMessage{
messageType: messageType,
frames: make(map[prepareKey]*preparedFrame),
data: data,
}
// Prepare a plain server frame.
_, frameData, err := pm.frame(prepareKey{isServer: true, compress: false})
if err != nil {
return nil, err
}
// To protect against caller modifying the data argument, remember the data
// copied to the plain server frame.
pm.data = frameData[len(frameData)-len(data):]
return pm, nil
}
func (pm *PreparedMessage) frame(key prepareKey) (int, []byte, error) {
pm.mu.Lock()
frame, ok := pm.frames[key]
if !ok {
frame = &preparedFrame{}
pm.frames[key] = frame
}
pm.mu.Unlock()
var err error
frame.once.Do(func() {
// Prepare a frame using a 'fake' connection.
// TODO: Refactor code in conn.go to allow more direct construction of
// the frame.
mu := make(chan bool, 1)
mu <- true
var nc prepareConn
c := &Conn{
conn: &nc,
mu: mu,
isServer: key.isServer,
compressionLevel: key.compressionLevel,
enableWriteCompression: true,
writeBuf: make([]byte, defaultWriteBufferSize+maxFrameHeaderSize),
}
if key.compress {
c.newCompressionWriter = compressNoContextTakeover
}
err = c.WriteMessage(pm.messageType, pm.data)
frame.data = nc.buf.Bytes()
})
return pm.messageType, frame.data, err
}
type prepareConn struct {
buf bytes.Buffer
net.Conn
}
func (pc *prepareConn) Write(p []byte) (int, error) { return pc.buf.Write(p) }
func (pc *prepareConn) SetWriteDeadline(t time.Time) error { return nil }

74
prepared_test.go Normal file
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@ -0,0 +1,74 @@
// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package websocket
import (
"bytes"
"compress/flate"
"math/rand"
"testing"
)
var preparedMessageTests = []struct {
messageType int
isServer bool
enableWriteCompression bool
compressionLevel int
}{
// Server
{TextMessage, true, false, flate.BestSpeed},
{TextMessage, true, true, flate.BestSpeed},
{TextMessage, true, true, flate.BestCompression},
{PingMessage, true, false, flate.BestSpeed},
{PingMessage, true, true, flate.BestSpeed},
// Client
{TextMessage, false, false, flate.BestSpeed},
{TextMessage, false, true, flate.BestSpeed},
{TextMessage, false, true, flate.BestCompression},
{PingMessage, false, false, flate.BestSpeed},
{PingMessage, false, true, flate.BestSpeed},
}
func TestPreparedMessage(t *testing.T) {
for _, tt := range preparedMessageTests {
var data = []byte("this is a test")
var buf bytes.Buffer
c := newConn(fakeNetConn{Reader: nil, Writer: &buf}, tt.isServer, 1024, 1024)
if tt.enableWriteCompression {
c.newCompressionWriter = compressNoContextTakeover
}
c.SetCompressionLevel(tt.compressionLevel)
// Seed random number generator for consistent frame mask.
rand.Seed(1234)
if err := c.WriteMessage(tt.messageType, data); err != nil {
t.Fatal(err)
}
want := buf.String()
pm, err := NewPreparedMessage(tt.messageType, data)
if err != nil {
t.Fatal(err)
}
// Scribble on data to ensure that NewPreparedMessage takes a snapshot.
copy(data, "hello world")
// Seed random number generator for consistent frame mask.
rand.Seed(1234)
buf.Reset()
if err := c.WritePreparedMessage(pm); err != nil {
t.Fatal(err)
}
got := buf.String()
if got != want {
t.Errorf("write message != prepared message for %+v", tt)
}
}
}