Simple pipeline example using Go channels

pipeline.go

package main

import "fmt"

// first adds 20 integers in sequence to a channel then closes
// it, signalling all of the writing is done.
func first(out chan<- int) {
	for x := 0; x < 20; x++ {
		out <- x
	}
	close(out)
}

// second reads integers from the in channel until the channel is
// closed, it adds 10 to each one, then writes the result to the
// out channel then closes that, signalling all of the writing is
// done.
func second(out chan<- int, in <-chan int) {
	for v := range in {
		out <- v + 10
	}
	close(out)
}

//  third reads the results and prints each one
func third(in <-chan int) {
	for v := range in {
		fmt.Println(v)
	}
}

// simple pipeline example using channels
func main() {
	source := make(chan int)
	result := make(chan int)

	go first(source)
	go second(result, source)
	third(result)
}