A very simple example of using a map of channels for pub/sub in go.
To run it go here http://play.golang.org/p/eXwppMgHR3
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August 30, 2024 01:22
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A very simple example of using a map of channels for pub/sub in go.
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| package main | |
| import ( | |
| "fmt" | |
| "time" | |
| ) | |
| func main() { | |
| pub1 := make(chan string) | |
| pub2 := make(chan string) | |
| sub1 := make(chan string) | |
| sub2 := make(chan string) | |
| sub3 := make(chan string) | |
| go listen("Subscriber 1", sub1) | |
| go listen("Subscriber 2", sub2) | |
| go listen("Subscriber 3", sub3) | |
| subscriptions := map[chan string][]chan string{ | |
| pub1: []chan string{sub1, sub2}, | |
| pub2: []chan string{sub2, sub3}, | |
| } | |
| go publish(subscriptions) | |
| pub1 <- "Hello, World!" | |
| pub2 <- "Hi, Universe!" | |
| pub1 <- "Goodbye, Cruel World!" | |
| subscriptions[pub1] = append(subscriptions[pub1], sub3) | |
| pub1 <- "Just kidding!" | |
| time.Sleep(2 * time.Second) | |
| } | |
| func listen(name string, subscriber chan string) { | |
| for { | |
| select { | |
| case message := <-subscriber: | |
| fmt.Printf("%q: %q\n", name, message) | |
| case <-time.After(time.Millisecond): | |
| } | |
| } | |
| } | |
| func publish(subscriptions map[chan string][]chan string) { | |
| for { | |
| for publisher, subscribers := range subscriptions { | |
| select { | |
| case message := <-publisher: | |
| for _, subscriber := range subscribers { | |
| subscriber <- message | |
| } | |
| case <-time.After(time.Millisecond): | |
| } | |
| } | |
| } | |
| } |
case <-time.After(time.Millisecond):
this line makes high CPU usage
This would be better suited for Ruby.
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This is a fantastic example, and very thought provoking.
But, if you choose to use something like this, don't ignore that this will trigger the race condition detector on this line:
subscriptions[pub1] = append(subscriptions[pub1], sub3)