Simplest way to limit number of concurrent go routines in a continuous feed

limitWorkers.go

package main

import (
    "fmt"
    "time"
)

func main() {
    ch := make(chan struct{}, 5)

    for {
        ch <- struct{}{}
        fmt.Println(len(ch))
        go worker(&ch)
        time.Sleep(time.Second * 3)
    }
}

func worker(ch *chan struct{}) {
        time.Sleep(time.Second * 30)
        <-*ch
}