Race condition
A race condition orrurs when two or more threads can access shared data and try to change it at the same time (concurrently).
Solving: mutex (mutual exclusion lock)
Example code showing how race condition happens:
go
package main
import (
"log"
"sync"
)
var userBalance float32 = 1000
func withdraw(amount float32, ws *sync.WaitGroup) {
if amount < userBalance {
userBalance -= amount
} else {
log.Printf("withdrawing %f: insufficient balance\n", amount)
}
ws.Done()
}
func main() {
ws := new(sync.WaitGroup)
ws.Add(2)
go withdraw(500, ws)
go withdraw(700, ws)
ws.Wait()
}package main
import (
"log"
"sync"
)
var userBalance float32 = 1000
func withdraw(amount float32, ws *sync.WaitGroup) {
if amount < userBalance {
userBalance -= amount
} else {
log.Printf("withdrawing %f: insufficient balance\n", amount)
}
ws.Done()
}
func main() {
ws := new(sync.WaitGroup)
ws.Add(2)
go withdraw(500, ws)
go withdraw(700, ws)
ws.Wait()
}