defer panic 异常捕获 golang中类似throw 重连机制

defer panic 异常捕获 golang中类似throw 重连机制

场景

1. 一般用于网络连接，数据库连接等情况

代码

package main

import (
    "flag"
    "fmt"
    "log"
    "time"
)

var (
    ImplementKey    string
    ImplementVersion string
)

func Register(h interface{}) {
    // 模拟注册过程，可能会发生 panic
    if ImplementKey == "" || ImplementVersion == "" {
        panic("key or version is empty")
    }
    fmt.Println("Registered successfully:", h)
}

type handler struct{}

func (my *handler) initConnector() {
    defer func() {
        if err := recover(); err != nil {
            log.Println("connector panic:", err)
            time.Sleep(time.Second * 3)
            go my.initConnector()
        }
    }()

    ImplementKey = flag.Lookup("build_name").Value.String()
    ImplementVersion = flag.Lookup("build_version").Value.String()
    Register(my)
}

func main() {
    // 定义命令行参数
    flag.String("build_name", "", "Build name")
    flag.String("build_version", "", "Build version")
    flag.Parse()

    h := &handler{}
    h.initConnector()
    fmt.Println("here")

    // 防止主 goroutine 提前退出
    time.Sleep(time.Second * 20)
}

流程图

graph TB classDef startend fill:#F5EBFF,stroke:#BE8FED,stroke-width:2px; classDef process fill:#E5F6FF,stroke:#73A6FF,stroke-width:2px; classDef decision fill:#FFF6CC,stroke:#FFBC52,stroke-width:2px; A([开始]):::startend --> B(定义命令行参数):::process B --> C(解析命令行参数):::process C --> D(创建 handler 实例):::process D --> E(调用 initConnector 方法):::process E --> F(注册 defer 函数):::process F --> G(设置 ImplementKey 和 ImplementVersion):::process G --> H{ImplementKey 或 ImplementVersion 为空?}:::decision H -- 是 --> I(触发 panic):::process I --> J(执行 defer 函数):::process J --> K(记录 panic 信息):::process K --> L(等待 3 秒):::process L --> M(重新调用 initConnector 方法):::process M --> F H -- 否 --> N(成功注册):::process N --> O(退出 initConnector 方法, 执行 defer 函数):::process O --> P(无 panic 情况 defer 函数正常结束):::process P --> Q(打印 here):::process Q --> R(主 goroutine 等待 20 秒):::process R --> S([结束]):::startend