func pumpStdout(ws *websocket.Conn, r io.Reader, done chan struct{}) {
defer func() {
ws.Close()
close(done)
}()
s := bufio.NewScanner(r)
for s.Scan() {
ws.SetWriteDeadline(time.Now().Add(writeWait))
if err := ws.WriteMessage(websocket.TextMessage, s.Bytes()); err != nil {
break
}
}
if s.Err() != nil {
log.Println("scan:", s.Err())
}
}
func writer(ws *websocket.Conn, lastMod time.Time) {
lastError := ""
pingTicker := time.NewTicker(pingPeriod)
fileTicker := time.NewTicker(filePeriod)
defer func() {
pingTicker.Stop()
fileTicker.Stop()
ws.Close()
}()
for {
select {
case <-fileTicker.C:
var p []byte
var err error
p, lastMod, err = readFileIfModified(lastMod)
if err != nil {
if s := err.Error(); s != lastError {
lastError = s
p = []byte(lastError)
}
} else {
lastError = ""
}
if p != nil {
ws.SetWriteDeadline(time.Now().Add(writeWait))
if err := ws.WriteMessage(websocket.TextMessage, p); err != nil {
return
}
}
case <-pingTicker.C:
ws.SetWriteDeadline(time.Now().Add(writeWait))
if err := ws.WriteMessage(websocket.PingMessage, []byte{}); err != nil {
return
}
}
}
}
func internalError(ws *websocket.Conn, msg string, err error) {
log.Println(msg, err)
ws.WriteMessage(websocket.TextMessage, []byte("Internal server error."))
}