golang中sync.Map并发创建、读取问题实战记录

struct SocketMap {
 sync.Mutex
 sockets map[string]*zmq4.Socket
}

func (pushList *SocketMap) push(ip string, data []byte) {
 pushList.Lock()
 defer pushList.UnLock()
 socket := pushList.sockets[string]
 if socket == nil {
 socket := zmq4.NewSocket()
 //do some initial operation like connect
 pushList.sockets[ip] = socket
 }
 socket.Send(data)
}

struct SocketMap {
 sockets sync.Map
}

func (pushList *SocketMap) push(ip string, data []byte) {
 var socket *zmq4.Socket 
 socketInter, ok = pushList.sockets.Load(ip)
 if !ok {
 socket = zmq4.NewSocket()
 //do some initial operation like connect
 pushList.sockets.Store(ip, socket)
 } else {
 socket = socketInter.(*zmq4.Socket)
 }
 socket.Send(data)
}

struct SocketMutex{
 sync.Mutex
 socket *zmq4.Socket
}
struct SocketMap {
 sockets sync.Map
}

func (pushList *SocketMap) push(ip string, data []byte) {
 var socket *SocketMutex 
 socketInter, ok = pushList.sockets.Load(ip)
 if !ok {
 socket = &{
  socket: zmq4.NewSocket()
 }
 //do some initial operation like connect
 pushList.sockets.Store(ip, newSocket)
 } else {
 socket = socketInter.(*SocketMutex)
 }
 socket.Lock()
 defer socket.Unlock()
 socket.socket.Send(data)
}

 func typeEncoder(t reflect.Type) encoderFunc {     
 if fi, ok := encoderCache.Load(t); ok {     
  return fi.(encoderFunc)      
 }          
          
 // To deal with recursive types, populate the map with an   
 // indirect func before we build it. This type waits on the  
 // real func (f) to be ready and then calls it. This indirect  
 // func is only used for recursive types.     
 var (         
  wg sync.WaitGroup       
  f encoderFunc        
 )          
 wg.Add(1)         
 fi, loaded := encoderCache.LoadOrStore(t, encoderFunc(func(e *encodeState, v reflect.Value, opts encOpts) {
  wg.Wait()        
  f(e, v, opts)        
 }))         
 if loaded {        
  return fi.(encoderFunc)      
 }          
           
 // Compute the real encoder and replace the indirect func with it.  
 f = newTypeEncoder(t, true)      
 wg.Done()         
 encoderCache.Store(t, f)       
 return f         
 }  

struct SocketMutex{
 sync.Mutex
 socket *zmq4.Socket
}
struct SocketMap {
 sockets sync.Map
}

func (pushList *SocketMap) push(ip string, data []byte) {
 type SocketFunc func()*SocketMutex
 var (
  socket *SocketMutex
  w sync.WaitGroup
 )
 socket = &SocketMutex {
  socket : zmq4.NewSocket()
 } 
 w.Add(1)
 socketf, ok = pushList.sockets.LoadOrStore(ip, SocketFunc(func()*SocketMutex) {
  w.Wait()
  return socket
 })
 if !ok {
  socket = &{
   socket: zmq4.NewSocket()
  }
  //do some initial operation like connect
  w.Done()
 } else {
  socket = socketInter.(*SockeFunc)()
 }
 socket.Lock()
 defer socket.Unlock()
 socket.socket.Send(data)
}