Golang函数重试机制实现

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 retryimpl

import (
	"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 := 0
	for 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 retryimpl

import (
	"errors"
	"fmt"
	"testing"
	"time"
)

// TestRetryV2_DoFunc
func TestRetryV2_DoFunc(t *testing.T) {
	testSuites := []struct {
		exceptExecCount int
		actualExecCount 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 int
		resMessage      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