Support log to file when run in background

Signed-off-by: Jianhui Zhao <jianhuizhao329@gmail.com>

broker.go

@@ -20,7 +20,6 @@
 package main
 
 import (
-    "log"
     "time"
     "strconv"
     "math/rand"
@@ -104,7 +103,7 @@ func (br *Broker) newSession(user *Client) bool {
         })
         dev.wsWrite(websocket.BinaryMessage, msg)
 
-        log.Println("New session:", sid)
+        rlog.Println("New session:", sid)
         return true
     } else {
         // Write to user
@@ -116,7 +115,7 @@ func (br *Broker) newSession(user *Client) bool {
         })
         user.wsWrite(websocket.BinaryMessage, msg)
 
-        log.Println("Device", devid, "offline")
+        rlog.Println("Device", devid, "offline")
         return false
     }
 }
@@ -125,7 +124,7 @@ func delSession(sessions map[string]*Session, sid string) {
     if session, ok := sessions[sid]; ok {
         delete(sessions, sid)
         session.user.wsClose()
-        log.Println("Delete session: ", sid)
+        rlog.Println("Delete session: ", sid)
 
         if session.dev != nil {
             msg := RttyMessageInit(&rtty.RttyMessage{
@@ -181,12 +180,12 @@ func (br *Broker) run() {
         case client := <- br.join:
             if client.isDev {
                 if _, ok := br.devices[client.devid]; ok {
-                    log.Println("ID conflicting:", client.devid)
+                    rlog.Println("ID conflicting:", client.devid)
                     client.wsClose();
                 } else {
                     client.isJoined = true
                     br.devices[client.devid] = client
-                    log.Printf("New device:id('%s'), description('%s')", client.devid, client.description)
+                    rlog.Printf("New device:id('%s'), description('%s')", client.devid, client.description)
                 }
             } else {
                 // From user browse
@@ -199,7 +198,7 @@ func (br *Broker) run() {
                 client.wsClose()
 
                 if dev, ok := br.devices[client.devid]; ok {
-                    log.Printf("Dead device:id('%s'), description('%s')", dev.devid, dev.description)
+                    rlog.Printf("Dead device:id('%s'), description('%s')", dev.devid, dev.description)
                     delete(br.devices, dev.devid)
                 }
 

client.go

@@ -20,7 +20,6 @@
 package main
 
 import (
-    "log"
     "time"
     "sync"
     "errors"
@@ -112,7 +111,7 @@ func (c *Client) readPump() {
         msgType, data, err := c.conn.ReadMessage()
         if err != nil {
             if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
-                log.Printf("error: %v", err)
+                rlog.Printf("error: %v", err)
             }
             break
         }
@@ -160,13 +159,13 @@ func (c *Client) writePump() {
 func serveWs(br *Broker, w http.ResponseWriter, r *http.Request) {
     devid := r.URL.Query().Get("devid")
     if devid == "" {
-        log.Println("devid required")
+        rlog.Println("devid required")
         return
     }
 
     conn, err := upgrader.Upgrade(w, r, nil)
     if err != nil {
-        log.Println(err)
+        rlog.Println(err)
         return
     }
 

main.go

@@ -22,7 +22,6 @@ package main
 import (
     "os"
     "fmt"
-    "log"
     "sync"
     "flag"
     "time"
@@ -106,22 +105,22 @@ func main() {
     key := flag.String("key", "", "keyFile Path")
 
     if syscall.Getuid() != 0 {
-        log.Println("Operation not permitted")
+        rlog.Println("Operation not permitted")
         os.Exit(1)
     }
 
     flag.Parse()
 
     rand.Seed(time.Now().Unix())
 
-    log.Println("rttys version:", rttys_version())
+    rlog.Println("rttys version:", rttys_version())
 
     br := newBroker()
     go br.run()
 
     statikFS, err := fs.New()
     if err != nil {
-        log.Fatal(err)
+        rlog.Fatal(err)
         return
     }
 
@@ -196,10 +195,10 @@ func main() {
     })
 
     if *cert != "" && *key != "" {
-        log.Println("Listen on: ", *port, "SSL on")
-        log.Fatal(http.ListenAndServeTLS(":" + strconv.Itoa(*port), *cert, *key, nil))
+        rlog.Println("Listen on: ", *port, "SSL on")
+        rlog.Fatal(http.ListenAndServeTLS(":" + strconv.Itoa(*port), *cert, *key, nil))
     } else {
-        log.Println("Listen on: ", *port, "SSL off")
-        log.Fatal(http.ListenAndServe(":" + strconv.Itoa(*port), nil))
+        rlog.Println("Listen on: ", *port, "SSL off")
+        rlog.Fatal(http.ListenAndServe(":" + strconv.Itoa(*port), nil))
     }
 }

rlog.go

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2017 Jianhui Zhao <jianhuizhao329@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
+ * USA
+ */
+
+package main
+
+import (
+    "os"
+    "fmt"
+    "log"
+    "github.com/mattn/go-isatty"
+)
+
+type RttyLog struct {
+    file string
+}
+
+const LOG_FILE = "/var/log/rtty.log"
+
+func (l *RttyLog) Write(b []byte) (n int, err error) {
+    if isatty.IsTerminal(os.Stdout.Fd()) {
+        fmt.Fprintf(os.Stderr, "%s", b)
+        return 0, nil
+    }
+
+    if l.file == "" {
+        return 0, nil
+    }
+
+    file, err := os.OpenFile(l.file, os.O_CREATE | os.O_WRONLY | os.O_APPEND, 0666)
+    if err != nil {
+        return 0, nil
+    }
+
+    st, _ := file.Stat()
+    if st.Size() > 1024 * 1024 {
+        file.Truncate(0)
+    }
+
+    defer file.Close()
+
+    fmt.Fprintf(file, "%s", b)
+
+    return 0, nil
+}
+
+var rlog = log.New(&RttyLog{file: LOG_FILE}, "", log.LstdFlags)