Go: One producer many consumers

Question

So I have seen a lot of ways of implementing one consumer and many producers in Go - the classic fanIn function from the Concurrency in Go talk.

What I want is a fanOut

Answer 1

We can handle multiple consumers without making the copy of channel data for each consumer.

Go playground: https://play.golang.org/p/yOKindnqiZv

package main

import (
    "fmt"
    "sync"
)

type data struct {
    msg string
    consumers int
}

func main() {
    ch := make(chan *data) // both block or non-block are ok
    var wg sync.WaitGroup
    consumerCount := 3 // specify no. of consumers

    producer := func() {
        obj := &data {
            msg: "hello everyone!",
            consumers: consumerCount,
        }
        ch <- obj
    }
    consumer := func(idx int) {
        defer wg.Done()
        obj := <-ch
        fmt.Printf("consumer %d received data %v\n", idx, obj)
        obj.consumers--
        if obj.consumers > 0 {
            ch <- obj // forward to others
        } else {
            fmt.Printf("last receiver: %d\n", idx)
        }
    }

    go producer()
    for i:=1; i<=consumerCount; i++ {
        wg.Add(1)
        go consumer(i)
    }

    wg.Wait()
}