How to intercept `runtime.Goexit()` signal

Question

package main

import  (
    "github.com/fatih/color"
    "github.com/gin-gonic/gin"
    "runtime"
)

var (
    Errors map[string]string
    err error
)

func CheckErr(err error) {
    if err != nil {
        pc, file, line, _ := runtime.Caller(1)
        color.New(color.FgRed).PrintfFunc()(" [app]")
        color.New(color.FgMagenta).PrintfFunc()("%v:", time.Now().Format("15:04:05.00000"))
        color.New(color.FgGreen).PrintfFunc()("%v] %v:%v:", path.Ext(runtime.FuncForPC(pc).Name())[1:], path.Base(file), line)
        color.Yellow(" %v", err)
        Errors["app "+time.Now().Format("15:04:05.00000")+" "+path.Ext(runtime.FuncForPC(pc).Name())[1:]+" "+path.Base(file)+":"+strconv.Itoa(line)] = err.Error()
        runtime.Goexit()
    }
}

func test(hello string) string{
    // ...
    if err!=nil{
        CheckErr(err)
    } 
    text := hello+" world"
    return test
}

func main() {
    req.POST("/hello", func(context *gin.Context) {
        message:=test("hello")
        context.JSON(200, gin.H{
            "message": message,
            "Errors": Errors,
        })
    }
}

• CheckErr is a function that collects error logs, prints errors and exits
• main is a gin service
• test is the data acquisition function of gin
• Cannot use go coroutine because test needs to return data

How can I go back to gin and return the error message when test fails?

Answer 1

If you insist on using runtime.Goexit() then you have to use another goroutine. Together with chan or sync.WaitGroup it works just fine since goexit runs all deferred calls.

// Goexit runs all deferred calls before terminating the goroutine. Because Goexit
// is not a panic, any recover calls in those deferred functions will return nil.

func CheckErr(err error, done chan struct{}) {
    defer func() { done <- struct{}{} }()
    if err != nil {
        // ...
        runtime.Goexit()
    }
}


func test(hello string) string {
    // ...
    if err != nil {
        done := make(chan struct{})
        go CheckErr(err, done)
        <-done
    }
    text := hello + " world"
    return text
}