awesome-patterns/concurrency/race_detection/main.go

package main

import (
	"fmt"
	"math/rand"
	"runtime"
	"sync"
	"time"
)

var balance int
var transacitonNo int

func main() {
	rand.Seed(time.Now().Unix())
	runtime.GOMAXPROCS(2)
	var wg sync.WaitGroup
	tranChan := make(chan bool)
	balance = 1000
	transacitonNo = 0
	fmt.Println("Start balance: $", balance)
	wg.Add(1)
	for i := 0; i < 100; i++ {
		go func(ii int, trChan chan (bool)) {
			transactionAmount := rand.Intn(25)
			transaction(transactionAmount)
			if ii == 99 {
				trChan <- true
			}
		}(i, tranChan)
	}
	go transaction(0)
	select {
	case <-tranChan:
		fmt.Println("Transaction Finished")
		wg.Done()
	}
	wg.Wait()
	close(tranChan)
	fmt.Println("Finial balance : $", balance)
}

func transaction(amt int) bool {
	approved := false
	if balance-amt < 0 {
		approved = false
	} else {
		approved = true
		balance = balance - amt
	}
	approvedText := "declined"
	if approved {
		approvedText = "approved"
	} else {

	}
	transacitonNo = transacitonNo + 1
	fmt.Println(transacitonNo, "Transaction For $", amt, approvedText)
	fmt.Println("\nRemaining Balance $", balance)
	return approved
}