實(shí)施死手或終止開關(guān)
package main
import (
"fmt"
"time"
"os"
)
const maxNoTickle = 50 // will bail out after this many no tickles
const maxWorking = 20 // pretendWork() will tickle this many times
const deadTicks = 250 // milliseconds for deadHand() to check for tickles
const reportTickles = 4 // consecutive tickles or no tickles to print something
var (
tickleMe bool // tell deadHand() we're still alive
countNoTickle int // consecutive no tickles
countGotTickle int // consecutive tickles
)
/**
* deadHand() - callback to kill program if nobody checks in after some period
*/
func deadHand() {
if !tickleMe {
countNoTickle++
countGotTickle = 0
if countNoTickle > maxNoTickle {
fmt.Println("No tickle max time reached. Bailing out!")
// panic("No real panic. Just checking stack")
os.Exit(0)
}
if countNoTickle % reportTickles == 0 {
// print dot for consecutive no tickles
fmt.Printf(".")
}
} else {
countNoTickle = 0
countGotTickle++
tickleMe = false // FIXME: might have race condition here
if countGotTickle % reportTickles == 0 {
// print tilda for consecutive tickles
fmt.Printf("~")
}
}
// call ourselves again
time.AfterFunc(deadTicks * time.Millisecond, deadHand)
}
/**
* init() - required to start deadHand
*/
func init() {
time.AfterFunc(250 * time.Millisecond, deadHand)
tickleMe = true
}
/**
* pretendWork() - your stuff that does its thing
*/
func pretendWork() {
for count := 0; count < maxWorking; count++ {
tickleMe = true // FIXME: might have race condition here
// print W pretending to be busy
fmt.Printf("W")
time.Sleep(100 * time.Millisecond)
}
}
func main() {
go workTillDone()
for {
// oops, program went loop-d-loopy
}
}
