Channel example, channel as queue with discard of messages

main.go

// go playground
// https://go.dev/play/p/3HjtqJlbMnE
package main

import (
	"log"
	"time"
)

func main() {
	log.SetFlags(log.Lmicroseconds)

	queueSize := 3
	ch := make(chan int, queueSize)

	go func() {
		for m := range ch {
			log.Printf("ok msg %d received", m)
			time.Sleep(10 * time.Millisecond)
		}
	}()

	for i := 0; i < 10; i++ {
		log.Printf("message %d, queue slots used %d/%d", i, len(ch), queueSize)

		select {
		case ch <- i:
		case <-time.After(5 * time.Millisecond):
			log.Printf("timeout! message %d discarded", i)
		}
	}

	time.Sleep(1 * time.Second)
}