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前言

在编写应用程序时，有时候会遇到一些短暂的错误，例如网络请求、服务链接终端失败等，这些错误可能导致函数执行失败。
但是如果稍后执行可能会成功，那么在一些业务场景下就需要重试了，重试的概念很简单，这里就不做过多阐述了

最近也正好在转golang语言，重试机制正好可以拿来练手，重试功能一般需要支持以下参数

• execFunc：需要被执行的重试的函数
• interval：重试的间隔时长
• attempts：尝试次数
• conditionMode：重试的条件模式，error和bool模式（这个参数用于控制传递的执行函数返回值类型检测

代码

package retryimplimport ("fmt""time"
)// RetryOptionV2 配置选项函数
type RetryOptionV2 func(retry *RetryV2)// RetryFunc 不带返回值的重试函数
type RetryFunc func() error// RetryFuncWithData 带返回值的重试函数
type RetryFuncWithData func() (any, error)// RetryV2 重试类
type RetryV2 struct {interval time.Duration // 重试的间隔时长attempts int           // 重试次数
}// NewRetryV2 构造函数
func NewRetryV2(opts ...RetryOptionV2) *RetryV2 {retry := RetryV2{interval: DefaultInterval,attempts: DefaultAttempts,}for _, opt := range opts {opt(&retry)}return &retry
}// WithIntervalV2 重试的时间间隔配置
func WithIntervalV2(interval time.Duration) RetryOptionV2 {return func(retry *RetryV2) {retry.interval = interval}
}// WithAttemptsV2 重试的次数
func WithAttemptsV2(attempts int) RetryOptionV2 {return func(retry *RetryV2) {retry.attempts = attempts}
}// DoV2 对外暴露的执行函数
func (r *RetryV2) DoV2(executeFunc RetryFunc) error {fmt.Println("[Retry.DoV2] begin execute func...")retryFuncWithData := func() (any, error) {return nil, executeFunc()}_, err := r.DoV2WithData(retryFuncWithData)return err
}// DoV2WithData 对外暴露知的执行函数可以返回数据
func (r *RetryV2) DoV2WithData(execWithDataFunc RetryFuncWithData) (any, error) {fmt.Println("[Retry.DoV2WithData] begin execute func...")n := 0for n < r.attempts {res, err := execWithDataFunc()if err == nil {return res, nil}n++time.Sleep(r.interval)}return nil, nil
}

测试验证

package retryimplimport ("errors""fmt""testing""time"
)// TestRetryV2_DoFunc
func TestRetryV2_DoFunc(t *testing.T) {testSuites := []struct {exceptExecCount intactualExecCount int}{{exceptExecCount: 3, actualExecCount: 0},{exceptExecCount: 1, actualExecCount: 1},}for _, testSuite := range testSuites {retry := NewRetryV2(WithAttemptsV2(testSuite.exceptExecCount),WithIntervalV2(1*time.Second),)err := retry.DoV2(func() error {fmt.Println("[TestRetry_DoFuncBoolMode] was called ...")if testSuite.exceptExecCount == 1 {return nil}testSuite.actualExecCount++return errors.New("raise error")})if err != nil {t.Errorf("[TestRetryV2_DoFunc] retyr.DoV2 execute failed and err:%+v", err)continue}if testSuite.actualExecCount != testSuite.exceptExecCount {t.Errorf("[TestRetryV2_DoFunc] got actualExecCount:%v != exceptExecCount:%v", testSuite.actualExecCount, testSuite.exceptExecCount)}}}// TestRetryV2_DoFuncWithData
func TestRetryV2_DoFuncWithData(t *testing.T) {testSuites := []struct {exceptExecCount intresMessage      string}{{exceptExecCount: 3, resMessage: "fail"},{exceptExecCount: 1, resMessage: "ok"},}for _, testSuite := range testSuites {retry := NewRetryV2(WithAttemptsV2(testSuite.exceptExecCount),WithIntervalV2(1*time.Second),)res, err := retry.DoV2WithData(func() (any, error) {fmt.Println("[TestRetryV2_DoFuncWithData] DoV2WithData was called ...")if testSuite.exceptExecCount == 1 {return testSuite.resMessage, nil}return testSuite.resMessage, errors.New("raise error")})if err != nil {t.Errorf("[TestRetryV2_DoFuncWithData] retyr.DoV2 execute failed and err:%+v", err)continue}if val, ok := res.(string); ok && val != testSuite.resMessage {t.Errorf("[TestRetryV2_DoFuncWithData] got unexcept result:%+v", val)continue}t.Logf("[TestRetryV2_DoFuncWithData] got result:%+v", testSuite.resMessage)}}

参考：GitCode - 开发者的代码家园