Golang Context TIme Out Setting

Golang Context TimeOut

It's quite easy to wrap a function for a timeout function.

package main

import (
    "context"
    "fmt"
    "time"
)

func forever() {
    for {
        fmt.Println("haha")
        time.Sleep(time.Second)
    }
}

func foreverWTO() {

    ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
    defer cancel()
    go forever()
    select {
    case <-ctx.Done():
        fmt.Println("got ctx Done message")
        return
    }
    return
}

func main() {
    fmt.Println("vim-go")
    //forever()
    foreverWTO()
}

Where forever is the function in the code, if we want to adding timeout function for forever.
You just addding a function foreverWTO and call foreverWTO(), you then can get timeout function.
It's quite efficient, since you don't need to modify th e core function forever, and just adding a TimeOut function for it.

Note, you can not add forever() in the select. Since no place to put forever in select.

• default: not right, since it will go to defualt directly. and always running on default

Adding Select to the bellow of forever with gorouting(no block), and adding select bellow the foever, it will block here until timeout.

Adding Watch

func foreverWTO() {

    ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
    defer cancel()
    go forever()
    for {
        select {
        default:
            fmt.Println("watchint timeout now")
            time.Sleep(time.Second)
        case <-ctx.Done():
            fmt.Println("got ctx Done message")
            return
        }
    }
    return
}

Adding A default for mention we are waiting for timeout in log. For loop will goto default forever until ctx's been triggered.