An example on multi producer (sender) and single consumer (receiver) golang channel

go-mpsc-channel.go

// https://go.dev/play/p/z7lFk4D-mhA
package main

import (
	"context"
	"fmt"
	"math/rand"
	"strconv"
	"strings"
	"sync"
	"time"
)

func longRunningTask(idx int) string {
	time.Sleep(time.Duration(rand.Intn(4)) * time.Second)
	return "task completed: " + strconv.Itoa(idx)
}

func main() {
	resultC := make(chan string, 20)
	var wg sync.WaitGroup

	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
	defer cancel()

	rand.Seed(time.Now().UnixNano())

	// run tasks
	for i := 0; i < 20; i++ {
		wg.Add(1)
		go func(ctx context.Context, i int) {
			defer wg.Done()
			result := longRunningTask(i)
			// ramdomly pick a case when timeout
			select {
			case <-ctx.Done():
				return
			default:
				resultC <- result
			}
		}(ctx, i)
	}

	wg.Wait()

	results := make([]string, 0)

runLoop:
	for {
		// safely drain the channel
		if len(resultC) == 0 {
			break runLoop
		}
		select {
		case r := <-resultC:
			results = append(results, r)
		default:
		}
	}

	// results handling, for example, print them
	fmt.Printf("running task results:\n%s", strings.Join(results, ", "))
}