/
reload.go
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/
reload.go
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// Copyright 2017 bee 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 run
import (
"bytes"
"net/http"
"time"
beeLogger "github.com/beego/bee/logger"
"github.com/gorilla/websocket"
)
// wsBroker maintains the set of active clients and broadcasts messages to the clients.
type wsBroker struct {
clients map[*wsClient]bool // Registered clients.
broadcast chan []byte // Inbound messages from the clients.
register chan *wsClient // Register requests from the clients.
unregister chan *wsClient // Unregister requests from clients.
}
func (br *wsBroker) run() {
for {
select {
case client := <-br.register:
br.clients[client] = true
case client := <-br.unregister:
if _, ok := br.clients[client]; ok {
delete(br.clients, client)
close(client.send)
}
case message := <-br.broadcast:
for client := range br.clients {
select {
case client.send <- message:
default:
close(client.send)
delete(br.clients, client)
}
}
}
}
}
// wsClient represents the end-client.
type wsClient struct {
broker *wsBroker // The broker.
conn *websocket.Conn // The websocket connection.
send chan []byte // Buffered channel of outbound messages.
}
// readPump pumps messages from the websocket connection to the broker.
func (c *wsClient) readPump() {
defer func() {
c.broker.unregister <- c
c.conn.Close()
}()
for {
_, _, err := c.conn.ReadMessage()
if err != nil {
if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
beeLogger.Log.Errorf("An error happened when reading from the Websocket client: %v", err)
}
break
}
}
}
// write writes a message with the given message type and payload.
func (c *wsClient) write(mt int, payload []byte) error {
c.conn.SetWriteDeadline(time.Now().Add(writeWait))
return c.conn.WriteMessage(mt, payload)
}
// writePump pumps messages from the broker to the websocket connection.
func (c *wsClient) writePump() {
ticker := time.NewTicker(pingPeriod)
defer func() {
ticker.Stop()
c.conn.Close()
}()
for {
select {
case message, ok := <-c.send:
if !ok {
// The broker closed the channel.
c.write(websocket.CloseMessage, []byte{})
return
}
c.conn.SetWriteDeadline(time.Now().Add(writeWait))
w, err := c.conn.NextWriter(websocket.TextMessage)
if err != nil {
return
}
w.Write(message)
n := len(c.send)
for i := 0; i < n; i++ {
w.Write([]byte("/n"))
w.Write(<-c.send)
}
if err := w.Close(); err != nil {
return
}
case <-ticker.C:
if err := c.write(websocket.PingMessage, []byte{}); err != nil {
return
}
}
}
}
var (
broker *wsBroker // The broker.
reloadAddress = ":12450" // The port on which the reload server will listen to.
upgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool { return true },
}
)
const (
writeWait = 10 * time.Second // Time allowed to write a message to the peer.
pongWait = 60 * time.Second // Time allowed to read the next pong message from the peer.
pingPeriod = (pongWait * 9) / 10 // Send pings to peer with this period. Must be less than pongWait.
)
func startReloadServer() {
broker = &wsBroker{
broadcast: make(chan []byte),
register: make(chan *wsClient),
unregister: make(chan *wsClient),
clients: make(map[*wsClient]bool),
}
go broker.run()
http.HandleFunc("/reload", func(w http.ResponseWriter, r *http.Request) {
handleWsRequest(broker, w, r)
})
go startServer()
beeLogger.Log.Infof("Reload server listening at %s", reloadAddress)
}
func startServer() {
err := http.ListenAndServe(reloadAddress, nil)
if err != nil {
beeLogger.Log.Errorf("Failed to start up the Reload server: %v", err)
return
}
}
func sendReload(payload string) {
message := bytes.TrimSpace([]byte(payload))
broker.broadcast <- message
}
// handleWsRequest handles websocket requests from the peer.
func handleWsRequest(broker *wsBroker, w http.ResponseWriter, r *http.Request) {
conn, err := upgrader.Upgrade(w, r, nil)
if err != nil {
beeLogger.Log.Errorf("error while upgrading server connection: %v", err)
return
}
client := &wsClient{
broker: broker,
conn: conn,
send: make(chan []byte, 256),
}
client.broker.register <- client
go client.writePump()
client.readPump()
}