go 开发小技巧

一、简介

       本篇文章会介绍go 开发小技巧。

二、go 开发技巧

2.1 Semaphore

type Semaphore chan struct{}func NewSemaphore(maxCount int) Semaphore {return make(chan struct{}, maxCount)
}func (s Semaphore) Acquire() {s <- struct{}{}
}func (s Semaphore) Release() {<-s
}

2.2 singleflight

    有点类似react的useMemo hook，会缓存函数结果

type SingleFlight struct {m map[string]*call
}type call struct {sync.Onceres any
}func newSingleFlight() *SingleFlight {return &SingleFlight{m: make(map[string]*call),}
}func (sf *SingleFlight) Do(key string, fn func() (any, error)) (any, error) {if sf.m[key] != nil {return sf.m[key].res, nil}ca := &call{}var err errorca.Once.Do(func() {if res, e := fn(); e == nil {ca.res = reserr = esf.m[key] = ca}})return ca.res, err
}

demo

func main() {var sf = newSingleFlight()var wg sync.WaitGroupvar t = time.Now()for i := 0; i < 10; i++ {wg.Add(1)go func() {res, _ := sf.Do("longFunc", func() (any, error) {time.Sleep(5 * time.Second)return 5, nil})fmt.Println(res)wg.Done()}()}wg.Wait()fmt.Println(time.Since(t))
}