參考連結：https://www.cnblogs.com/charlieroro/p/11112526.html

1.實現了對golang map的key的處理，如計算交集，並集等。

package main

import (
    "fmt"
    "k8s.io/apimachinery/pkg/util/sets"
)

func main(){
    map1 := map[string]int{"aaa":1,"bbb":2,"ccc":3}
    map2 := map[string]int{"ccc":1,"ddd":2,"eee":3}
    newmap1 := sets.StringKeySet(map1)
    newmap2 :
 
= sets.StringKeySet(map2)
    fmt.Println(newmap1.List(),newmap2.List())
    fmt.Println(newmap1.HasAny(newmap2.List()...)) //3個點用於把陣列打散為單個元素
}結果：true

2.k8s.io/apimachinery/pkg/util/wait/wait.go

函式：func ExponentialBackoff(backoff Backoff, condition ConditionFunc) error

ExponentialBackoff ： 可以實現在函式執行錯誤後實現以指數退避方式的延時重試。ExponentialBackoff內部使用的是time.Sleep

ExponentialBackoff的首個入參Backoff如下：

• Duration：表示初始的延時時間
• Factor：指數退避的因子
• Jitter：可以看作是偏差因子，該值越大，每次重試的延時的可選區間越大
• Steps：指數退避的步數，可以看作程式的最大重試次數
• Cap：用於在Factor非0時限制最大延時時間和最大重試次數，為0表示不限制最大延時時間

type Backoff struct {
    // The initial duration.
    Duration time.Duration
    // Duration is multiplied by factor each iteration. Must be greater
    
 
// than or equal to zero.
    Factor float64
    // The amount of jitter applied each iteration. Jitter is applied after
    // cap.
    Jitter float64
    // The number of steps before duration stops changing. If zero, initial
    // duration is always used. Used for exponential backoff in combination
    // with Factor.
    Steps int
    // The returned duration will never be greater than cap *before* jitter
    // is applied. The actual maximum cap is `cap * (1.0 + jitter)`.
    Cap time.Duration
}

當Factor和Jitter都為0時，可以看到排程週期是相同的，即Duration的值(1s)。

import (
    "fmt"
    "k8s.io/apimachinery/pkg/util/wait"
    "time"
)


func main(){
    var DefaultRetry = wait.Backoff{
        Steps:    5,
        Duration: 1 * time.Second,
        Factor:   0,
        Jitter:   0,
    }

    fmt.Println(wait.ExponentialBackoff(DefaultRetry,func() (bool, error){
        fmt.Println(time.Now())
        return false,nil
    }))
}

結果：
2019-07-05 10:17:33.9610108 +0800 CST m=+0.079831101
2019-07-05 10:17:34.961132 +0800 CST m=+1.079952301
2019-07-05 10:17:35.961512 +0800 CST m=+2.080332301
2019-07-05 10:17:36.9625144 +0800 CST m=+3.081334701
2019-07-05 10:17:37.9636334 +0800 CST m=+4.082453701
timed out waiting for the condition