UDP实现一种双机备份的

关键字:

　　udpclient、Udp超时、软备份、事件通知

问题场景：
　　现实环境中为了保证程序健壮性会采用守护进程（看门狗）、备份程序等方式，实现理论上的热备。下文采用UDP协议配合自定义上层协议流程，实现一种简单的双机备份策略。两个功能程序 具有相同业务功能 但同一时刻只有一个进行服务，另外一个下文称为兄弟，进行待命。当主失去连接或发生命令指派时，改变自身状态为主进行服务。
　　该模型可抽象理解为一种进程间互斥，即保证二者状态不一致。程序初始双方状态都为未指定，即二者初始地位平等，通过协商报文，随机指定其一为主，则兄弟程序自动改变自身状态为备。主进行状态保持报文发送，备进行响应以确定对方状态。通过超时控制解决兄弟其一断线通知。并通过事件将状态改变、连接状态及重要报文信息抛出给订阅者。

术语定义：
主 备 协商 指派 连接 回执   在线
active standby negotiate designed connect receipt Frame Online
初始状态及流程：
 
　　由于程序的限定性初始状态仅3种，未指定&未指定，未指定&主，未指定&备（active和standby与程序无关因而未指定&主和主&未指定逻辑上是一样的），对应的流程包括未指定状态->协商->指定A|S->发送keepalive  判断超时->指定 ..
 
协议报文格式
 1     /// <summary>
 2     /// 2015-05-11 
 3     /// kisi
 4     /// 双机备份协商协议实现
 5     /// 定长
 6     /// FH | Head | ASState | ID | data |
 7     /// </summary>
 8     /// <summary>
 9         /// 数据帧开始标志
10         /// </summary>
11         private byte FrameHead = 0xFF;
12 
13         /// <summary>
14         ///  定义端口
15         /// </summary>
16         private int listenPort = 1101;
17 
18         /// <summary>
19         ///  数据帧类型
20         ///  协商,发送token
21         ///  指定,确定主从
22         ///  连接,保持联系
23         /// </summary>
24         private enum HeadOptions
25         {
26             // The flag for 协商 is 10100000.
27             Negotiate = 0xA0,
28             // The flag for 指定 is 10100101.
29             Designate = 0xA5,
30             // The flag for 连接保持 is 10101111.
31             Connected = 0xAA,
32             // The flag for 响应报文
33             Responsed = 0xAF
34         }
35 
36         private enum StateOptions
37         {
38             // The Initial state
39             Initial = 0x00,
40             // 主，进行数据采集及业务逻辑
41             Active = 0x01,
42             // 备，进行数据同步及连接状态保持
43             Standby = 0x02
44         }
View Code

 

UDP封装部分
 1         private IPEndPoint _RemoteIPEndPoint = null;
 2         // 定义UDP发送和接收client
 3         private UdpClient uclientReceive = null;
 4         private UdpClient uclientSend = null;
 5         private ManualResetEvent sendDone = new ManualResetEvent(false);
 6         private ManualResetEvent receiveDone = new ManualResetEvent(false);
 7         //初始状态未指定
 8         private StateOptions state = StateOptions.Initial;
 9         private byte value = 0;
10         private byte frameid = 0;
11         private byte lossFramecount = 0;
12         private List<SendFrame> listSend = new List<SendFrame>();
13         private List<int> listRemaindel = new List<int>();
14         private bool initial = true;
15         private bool initialconnect = true;
16         private DateTime lastConnectTime = DateTime.Now;
17         object lockList = new object();
18         public StateEvent trevent = new StateEvent();
19 
20         public ASNegotiate(string remoteip, int port)
21         {
22             if (port > 1000)
23                 listenPort = port;
24             _RemoteIPEndPoint = new IPEndPoint(IPAddress.Parse(remoteip), listenPort);
25             this.value = GetRandom();
26         }
27 
28         private byte GetRandom()
29         {
30             return Convert.ToByte(new Random().Next(0, 255));
31         }
32 
33         private byte[] Package(HeadOptions head, byte id, StateOptions state, byte value)
34         {
35             byte[] byteData = new byte[5];
36             byteData[0] = FrameHead;
37             byteData[1] = (byte)head;
38             byteData[2] = (byte)state;
39             byteData[3] = id;
40             byteData[4] = value;
41             return byteData;
42         }
43 
44         #region 发送
45         private void SendMsg(byte[] sendbytes)
46         {
47             if (uclientSend == null)
48                 uclientSend = new UdpClient();
49             uclientSend.BeginSend(sendbytes, sendbytes.Length, _RemoteIPEndPoint, new AsyncCallback(SendCallback), uclientSend);
50             sendDone.WaitOne();
51         }
52 
53         private void SendCallback(IAsyncResult iar)
54         {
55             UdpClient u = (UdpClient)iar.AsyncState;
56             string msg = string.Format("{0}: Frameid={1} : value ={2}number of bytes sent: {3}", state.ToString(), frameid, value, u.EndSend(iar));
57             trevent.RaiseEvent((byte)state,0,msg);
58             Console.WriteLine(msg);
59             sendDone.Set();
60         }
61         #endregion
62 
63         #region 接收
64         public void ReceiveMsg()
65         {
66             IPEndPoint e = new IPEndPoint(IPAddress.Any, listenPort);
67             uclientReceive = new UdpClient(e);
68             while (true)
69             {
70                 uclientReceive.BeginReceive(new AsyncCallback(ReceiveCallback), uclientReceive);
71                 receiveDone.WaitOne();
72                 Thread.Sleep(100);
73             }
74 
75         }
76 
77         private void ReceiveCallback(IAsyncResult iar)
78         {
79             UdpClient u = (UdpClient)iar.AsyncState;
80             IPEndPoint e = null;
81             if (iar.IsCompleted)
82             {
83                 Byte[] receiveBytes = u.EndReceive(iar, ref e);
84                 if (CheckFrame(receiveBytes))
85                 {
86                     string msg = string.Format("Received: headoption:{0}-state:{1}-{2}-{3}", receiveBytes[1], receiveBytes[2], receiveBytes[3], receiveBytes[4]);
87                     Console.WriteLine(msg);
88                     trevent.RaiseEvent((byte)state, 0, msg);
89                     AnalysisFrame(receiveBytes[1], receiveBytes[2], receiveBytes[3], receiveBytes[4]);
90                 }
91             }
92             receiveDone.Set();
93         }
94         #endregion
View Code
 
超时控制部分
 1 public class SendFrame
 2     {
 3         private int _ID;
 4 
 5         public int ID
 6         {
 7             get { return _ID; }
 8             set { _ID = value; }
 9         }
10 
11         private DateTime _SendTime;
12 
13         public DateTime SendTime
14         {
15             get { return _SendTime; }
16             set { _SendTime = value; }
17         }
18 
19         public SendFrame(int id, DateTime datetime)
20         {
21             this.ID = id;
22             this.SendTime = datetime;
23         }
24 
25         public override int GetHashCode()
26         {
27             return ID;
28         }
29 
30         public override bool Equals(object obj)
31         {
32             if (obj == null) return false;
33             SendFrame objAsFrame = obj as SendFrame;
34             if (objAsFrame == null) return false;
35             else return Equals(objAsFrame);
36         }
37 
38         public bool Equals(SendFrame other)
39         {
40             if (other == null) return false;
41             return (this.ID.Equals(other.ID));
42         }
43     }
44 
45 //以下为ASNegotiate类内容定义一个发送的对象的list
46         private List<SendFrame> listSend = new List<SendFrame>();
47         private List<int> listRemaindel = new List<int>();
48         public void ReceiptTimeout()
49         {
50             while (true)
51             {
52                 if (state == StateOptions.Standby)
53                 {
54                     if ((DateTime.Now - lastConnectTime).TotalSeconds > 60)
55                     {
56                         state = StateOptions.Active;
57                         string msg = "失去连接，我要激活";
58                         Console.WriteLine(msg);
59                         trevent.RaiseEvent((byte)state, 0, msg);
60                     }
61                 }
62                 listRemaindel.Clear();
63                 lock (lockList)
64                 {
65                     foreach (SendFrame _frame in listSend)
66                     {
67                         if ((DateTime.Now - _frame.SendTime).TotalSeconds > 10)
68                         {
69                             lossFramecount++;
70                             listRemaindel.Add(_frame.ID);
71                         }
72                     }
73                     foreach (int _frameid in listRemaindel)
74                     {
75                         listSend.Remove(new SendFrame(_frameid, DateTime.Now));
76                     }
77                     if (lossFramecount > 5)
78                     {
79                         lossFramecount = 0;
80                         if (state == StateOptions.Active)
81                         {
82                             string msg = "standy 端超时";
83                             Console.WriteLine(msg);
84                             trevent.RaiseEvent((byte)state, 0, msg);
85                         }
86                         else if (state == StateOptions.Initial)
87                         {
88                             state = StateOptions.Active;
89                             initial = false;
90                             string msg = "无法协商，我要激活";
91                             Console.WriteLine(msg);
92                             trevent.RaiseEvent((byte)state, 0, msg);
93                         }
94                     }
95                 }
96                 Thread.Sleep(1000);
97             }
98         }
View Code

 

事件通知

 1 public class StateEvent
 2     {
 3         //定义事件参数类
 4         public class StateEventArgs : EventArgs
 5         {
 6             public readonly byte state;
 7 
 8             public readonly byte online;
 9 
10             public readonly string msg;
11 
12             public StateEventArgs(byte _state, byte _online, string value)
13             {
14                 state = _state;
15                 online = _online;
16                 msg = value;
17             }
18         }
19 
20         public delegate void MyEventHandler(object sender, StateEventArgs e);
21 
22         //用event 关键字声明事件对象
23 
24         public event MyEventHandler ASEvent;
25 
26         //事件触发方法
27         protected virtual void OnTestEvent(StateEventArgs e)
28         {
29 
30             if (ASEvent != null)
31                 ASEvent(this, e);
32 
33         }
34 
35         //引发事件
36         public void RaiseEvent(byte _state, byte _online, string value)
37         {
38             StateEventArgs e = new StateEventArgs(_state, _online, value);
39             OnTestEvent(e);
40         }
41     }
View Code

 

调用方式，采用winform窗体调用，订阅事件，注意事件响应回显非界面线程，窗体显示内容需要invoke。

 1        private void button3_Click(object sender, EventArgs e)
 2         {
 3             string remoteip = this.txtbrotherip.Text.Trim();
 4             ASNegotiate m_negotiate = new ASNegotiate(remoteip, 0);
 5             m_negotiate.trevent.ASEvent += new StateEvent.MyEventHandler(GenerateEvent);
 6             m_negotiate.Start();
 7         }
 8 
 9         public void GenerateEvent(object sender, StateEvent.StateEventArgs e)
10         {
11             string state = "";
12             string online = "";
13             if (e.state == 0x00)
14             {
15                 state = "未指定";
16             }
17             else if (e.state == 0x01)
18             {
19                 state = "主";
20             }
21             else if (e.state == 0x02)
22             {
23                 state = "备";
24             }
25             else
26             {
27                 state = "";
28             }
29             if (e.online == 0x00)
30             {
31                 online = "兄弟在线";
32             }
33             else if (e.online == 0x01)
34             {
35                 online = "兄弟离线";
36             }
37             else
38             {
39                 online = "";
40             }
41             lock (objlock)
42             {
43                 stateout(state);
44                 onlineout(online);
45                 MessageOut(e.msg);
46             }
47         }
View Code

 


 
 
posted @ 2015-05-12 22:44  beeshow00  阅读(500)  评论(1)  编辑  收藏  举报