Golang Round Robin - Algorithm

round_robin.go

package main

import (
	"fmt"
	"sync"
	"sync/atomic"
)

func main() {
	concurrentCalls := 20

	r := NewRobin("1", "2", "3", "4", "5")

	urlCalledChan := make(chan string)

	var wg sync.WaitGroup
	for i := 0; i < concurrentCalls; i++ {
		wg.Add(1)
		go func() {
			nextUrl := r.Next()
			urlCalledChan <- nextUrl

			wg.Done()
		}()
	}

	go func() {
		for url := range urlCalledChan {
			fmt.Println(url)
		}
	}()
	wg.Wait()

}

type robin struct {
	next int64
	urls []string
}

func NewRobin(urls ...string) *robin {
	return &robin{
		urls: urls,
	}
}

func (r *robin) Next() string {
	next := atomic.AddInt64(&r.next, int64(1))
	return r.urls[(int(next)-1)%len(r.urls)]
}