package main

import (
    "fmt"
    "sync"
)

func main() {
    a1 := []string{"apple", "apricot"}

    chan1 := make(chan string)
    chan2 := make(chan string)
    chan3 := make(chan string)

    var wg sync.WaitGroup

    go Pipe1(chan2, chan1, &wg)
    go Pipe2(chan3, chan2, &wg)
    go Pipe3(chan3, &wg)

    func (data []string) {
        defer wg.Done()
        for _, s := range data {
            wg.Add(1)
            chan1 <- s
        }
        go func() {
            wg.Wait()
            close(chan1)
        }()
    }(a1)
}

func Pipe1(out chan<- string, in <-chan string, wg *sync.WaitGroup) {
    defer wg.Done()
    for s := range in {
        wg.Add(1)
        out <- s + "s are"
    }
}
func Pipe2(out chan<- string, in <-chan string, wg *sync.WaitGroup) {
    defer wg.Done()
    for s := range in {
        wg.Add(1)
        out <- s + " good for you"
    }
}
func Pipe3(in <-chan string, wg *sync.WaitGroup) {
    defer wg.Done()
    for s := range in {
        wg.Add(1)
        fmt.Println(s)
    }
}

apples are good for you
apricots are good for you