package main

import (
    "container/ring"
    "fmt"
    "time"
)

func main() {
    coffee := []string{"kenya", "guatemala", "ethiopia"}

    // create a ring and populate it with some values
    r := ring.New(len(coffee))
    for i := 0; i < r.Len(); i++ {
        r.Value = coffee[i]
        r = r.Next()
    }

    // print all values of the ring, easy done with ring.Do()
    r.Do(func(x interface{}) {
        fmt.Println(x)
    })

    // .. or each one by one.
    for _ = range time.Tick(time.Second * 1) {
        r = r.Next()
        fmt.Println(r.Value)
    }
}