使用go实现一个超级mini的消息队列的示例代码

目录

• 前言
• 目的
• 设计

• 协议
• 队列
• broker
• 删除消息
• 生产者
• 消费者
• 启动

type Msg struct {
   Id int64
   TopicLen int64
   Topic string
   // 1-consumer 2-producer 3-comsumer-ack 4-error
   MsgType int64 // 消息类型
   Len int64 // 消息长度
   Payload []byte // 消息
}

func BytesToMsg(reader io.Reader) Msg {
   m := Msg{}
   var buf [128]byte
   n, err := reader.Read(buf[:])
   if err != nil {
      fmt.Println("read failed, err:", err)
   }
   fmt.Println("read bytes:", n)
   // id
   buff := bytes.NewBuffer(buf[0:8])
   binary.Read(buff, binary.LittleEndian, &m.Id)
   // topiclen
   buff = bytes.NewBuffer(buf[8:16])
   binary.Read(buff, binary.LittleEndian, &m.TopicLen)
   // topic
   msgLastIndex := 16 + m.TopicLen
   m.Topic = string(buf[16: msgLastIndex])
   // msgtype
   buff = bytes.NewBuffer(buf[msgLastIndex : msgLastIndex + 8])
   binary.Read(buff, binary.LittleEndian, &m.MsgType)
   buff = bytes.NewBuffer(buf[msgLastIndex : msgLastIndex + 16])
   binary.Read(buff, binary.LittleEndian, &m.Len)
   if m.Len <= 0 {
      return m
   }
   m.Payload = buf[msgLastIndex + 16:]
   return m
}
func MsgToBytes(msg Msg) []byte {
   msg.TopicLen = int64(len([]byte(msg.Topic)))
   msg.Len = int64(len([]byte(msg.Payload)))
   var data []byte
   buf := bytes.NewBuffer([]byte{})
   binary.Write(buf, binary.LittleEndian, msg.Id)
   data = append(data, buf.Bytes()...)
   buf = bytes.NewBuffer([]byte{})
   binary.Write(buf, binary.LittleEndian, msg.TopicLen)
   data = append(data, buf.Bytes()...)
   data = append(data, []byte(msg.Topic)...)
   buf = bytes.NewBuffer([]byte{})
   binary.Write(buf, binary.LittleEndian, msg.MsgType)
   data = append(data, buf.Bytes()...)
   buf = bytes.NewBuffer([]byte{})
   binary.Write(buf, binary.LittleEndian, msg.Len)
   data = append(data, buf.Bytes()...)
   data = append(data, []byte(msg.Payload)...)
   return data
}

package broker
import (
   "container/list"
   "sync"
)
type Queue struct {
   len int
   data list.List
}
var lock sync.Mutex
func (queue *Queue) offer(msg Msg) {
   queue.data.PushBack(msg)
   queue.len = queue.data.Len()
}
func (queue *Queue) poll() Msg{
   if queue.len == 0 {
      return Msg{}
   }
   msg := queue.data.Front()
   return msg.Value.(Msg)
}
func (queue *Queue) delete(id int64) {
   lock.Lock()
   for msg := queue.data.Front(); msg != nil; msg = msg.Next() {
      if msg.Value.(Msg).Id == id {
         queue.data.Remove(msg)
         queue.len = queue.data.Len()
         break
      }
   }
   lock.Unlock()
}

package broker
import (
   "bufio"
   "net"
   "os"
   "sync"
   "time"
)
var topics = sync.Map{}
func handleErr(conn net.Conn)  {
   defer func() {
      if err := recover(); err != nil {
         println(err.(string))
         conn.Write(MsgToBytes(Msg{MsgType: 4}))
      }
   }()
}
func Process(conn net.Conn) {
   handleErr(conn)
   reader := bufio.NewReader(conn)
   msg := BytesToMsg(reader)
   queue, ok := topics.Load(msg.Topic)
   var res Msg
   if msg.MsgType == 1 {
      // comsumer
      if queue == nil || queue.(*Queue).len == 0{
         return
      }
      msg = queue.(*Queue).poll()
      msg.MsgType = 1
      res = msg
   } else if msg.MsgType == 2 {
      // producer
      if ! ok {
         queue = &Queue{}
         queue.(*Queue).data.Init()
         topics.Store(msg.Topic, queue)
      }
      queue.(*Queue).offer(msg)
      res = Msg{Id: msg.Id, MsgType: 2}
   } else if msg.MsgType == 3 {
      // consumer ack
      if queue == nil {
         return
      }
      queue.(*Queue).delete(msg.Id)
   }
   conn.Write(MsgToBytes(res))
}

func Save()  {
   ticker := time.NewTicker(60)
   for {
      select {
      case <-ticker.C:
         topics.Range(func(key, value interface{}) bool {
            if value == nil {
               return false
            }
            file, _ := os.Open(key.(string))
            if file == nil {
               file, _ = os.Create(key.(string))
            }
            for msg := value.(*Queue).data.Front(); msg != nil; msg = msg.Next() {
               file.Write(MsgToBytes(msg.Value.(Msg)))
            }
            _ := file.Close()
            return false
         })
      default:
         time.Sleep(1)
      }
   }
}

package main
import (
   "awesomeProject/broker"
   "fmt"
   "net"
)
func main()  {
   listen, err := net.Listen("tcp", "127.0.0.1:12345")
   if err != nil {
      fmt.Print("listen failed, err:", err)
      return
   }
   go broker.Save()
   for {
      conn, err := listen.Accept()
      if err != nil {
         fmt.Print("accept failed, err:", err)
         continue
      }
      go broker.Process(conn)
   }
}

package main
import (
   "awesomeProject/broker"
   "fmt"
   "net"
)
func produce() {
   conn, err := net.Dial("tcp", "127.0.0.1:12345")
   if err != nil {
      fmt.Print("connect failed, err:", err)
   }
   defer conn.Close()
   msg := broker.Msg{Id: 1102, Topic: "topic-test",  MsgType: 2,  Payload: []byte("我")}
   n, err := conn.Write(broker.MsgToBytes(msg))
   if err != nil {
      fmt.Print("write failed, err:", err)
   }
   fmt.Print(n)
}

package main
import (
   "awesomeProject/broker"
   "bytes"
   "fmt"
   "net"
)
func comsume() {
   conn, err := net.Dial("tcp", "127.0.0.1:12345")
   if err != nil {
      fmt.Print("connect failed, err:", err)
   }
   defer conn.Close()
   msg := broker.Msg{Topic: "topic-test",  MsgType: 1}
   n, err := conn.Write(broker.MsgToBytes(msg))
   if err != nil {
      fmt.Println("write failed, err:", err)
   }
   fmt.Println("n", n)
   var res [128]byte
   conn.Read(res[:])
   buf := bytes.NewBuffer(res[:])
   receMsg := broker.BytesToMsg(buf)
   fmt.Print(receMsg)
   // ack
   conn, _ = net.Dial("tcp", "127.0.0.1:12345")
   l, e := conn.Write(broker.MsgToBytes(broker.Msg{Id: receMsg.Id, Topic: receMsg.Topic, MsgType: 3}))
   if e != nil {
      fmt.Println("write failed, err:", err)
   }
   fmt.Println("l:", l)
}