package main import ( "crypto/md5" "fmt" "io" "time" ) type IdGenerator struct { id chan int64 } func NewIdGenerator() *IdGenerator { g := IdGenerator{} g.id = make(chan int64) go func() { var i int64 for i = 0; ; i++ { g.id <- i } }() return &g } func (id *IdGenerator) Hash() string { h := md5.New() ns := time.Now().UnixNano() + <-id.id io.WriteString(h, fmt.Sprintf("%d", ns)) return fmt.Sprintf("%x", h.Sum(nil)) }