diff --git a/f7/udplog.py b/f7/udplog.py
index 086b67d..9329b64 100644
--- a/f7/udplog.py
+++ b/f7/udplog.py
@@ -1,20 +1,89 @@
 # -*- coding: utf-8 -*-
 
-class Udplog:
+import time
+import datetime
+import traceback
+import _thread
+import threading
 
+class _LocalLogNode:
+    def __init__(self, msg):
+        self.msg = msg
+        self.nextNode = None
+
+class _UdpLog:
     _instance = None
 
     @classmethod
     def instance(cls):
-        if not _instance:
-            _instance = UdpLog()
-        return _instance
+        if not cls._instance:
+            cls._instance = _UdpLog()
+        return cls._instance
 
     def __init__(self):
-        pass
+        self._topNode = None
+        self._botNode = None
+        self._workNode = None
+        self._msgLock = threading.Lock()
 
     def init(self):
-        pass
+        _thread.start_new_thread(self._saveToFile, ())
 
     def unInit(self):
         pass
+
+    def info(self, msg):
+        self._addLog(str(datetime.datetime.now()) + '[INFO]' + str(msg))
+
+    def debug(self, msg):
+        self._addLog(str(datetime.datetime.now()) + '[DEBUG]' + str(msg))
+
+    def warning(self, msg):
+        self._addLog(str(datetime.datetime.now()) + '[WARNING]' + str(msg))
+
+    def error(self, msg):
+        self._addLog(str(datetime.datetime.now()) + '[ERROR]' + str(msg))
+
+    def _addLog(self, msg):
+        node = _LocalLogNode(msg)
+        self._msgLock.acquire()
+        try:
+            if self._botNode == None:
+                self._topNode = node
+                self._botNode = node
+            else:
+                self._botNode.nextNode = node
+                self._botNode = node
+        except:
+            traceback.print_exc()
+        finally:
+            self._msgLock.release()
+
+
+    def _saveToFile(self):
+        try:
+            while True:
+                if not self._workNode and self._topNode:
+                    self._msgLock.acquire()
+                    try:
+                        self._workNode = self._topNode
+                        self._topNode = None
+                        self._botNode = None
+                    finally:
+                        self._msgLock.release()
+                if self._workNode:
+                    filename = datetime.datetime.now().strftime('log%Y-%m-%d.log')
+                    try:
+                        with open(os.path.join(LOG_DIR, filename), 'a') as f:
+                            while self._workNode:
+                                nextNode = self._workNode.nextNode
+                                f.write(self._workNode.msg + '\r\n')
+                                self._workNode = nextNode
+                    except Exception as e:
+                        print(str(e), flush=True)
+                time.sleep(10)
+        except:
+            traceback.print_exec()
+
+def instance():
+    return _UdpLog.instance()
diff --git a/test/app.py b/test/app.py
new file mode 100644
index 0000000..4afb760
--- /dev/null
+++ b/test/app.py
@@ -0,0 +1,11 @@
+# -*- coding: utf-8 -*-
+
+import sys
+import time
+
+sys.path.append('..')
+
+import f7.udplog
+
+f7.udplog.instance().init()
+time.sleep(5)