全局事件总线（Global EventBus）在Go语言中的实现

huangapple
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英文:

Global EventBus in GoLang

问题

我正在尝试学习GO，并尝试不同的概念。现在我正在尝试使用PubSub方法，但是在应用程序内部进行。我有一个EventBus，并且我正在尝试通过依赖注入传递实例。然而，当我运行应用程序时，什么都没有发生。

主要代码如下：

  1. package main
  3. import (
  4. 	"github.com/asaskevich/EventBus"
  5. 	modelA "interfaces/internal/modelA"
  6. 	modelB "interfaces/internal/modelB"
  7. )
  9. func main() {
  10. 	bus := EventBus.New()
  12. 	a := &modelA.Bus{EventBus: bus}
  13. 	a.Send()
  15. 	b := &modelB.Bus{
  16. 		EventBus: bus,
  17. 	}
  18. 	b.Receive()
  20. }

internal/modelA代码如下：

  1. package modelA
  3. import (
  4. 	"fmt"
  5. 	"github.com/asaskevich/EventBus"
  6. )
  8. type Bus struct {
  9. 	EventBus EventBus.Bus
  10. }
  12. type ModelAService interface {
  13. 	Run()
  14. 	Send()
  15. }
  17. func calculator(a int, b int) {
  18. 	fmt.Printf("ModelA %d\n", a+b)
  19. }
  21. func (bus *Bus) Receive() {
  22. 	err := bus.EventBus.Subscribe("testMessageFromB", calculator)
  23. 	if err != nil {
  24. 		fmt.Printf("Error Receiving message...")
  25. 	}
  26. }
  28. func (bus *Bus) Send() {
  29. 	bus.EventBus.Publish("testMessageFromA", 33, 33)
  30. }

internal/modelB代码如下：

  1. package modelB
  3. import (
  4. 	"fmt"
  5. 	"github.com/asaskevich/EventBus"
  6. )
  8. type Bus struct {
  9. 	EventBus EventBus.Bus
  10. }
  12. type ModelBService interface {
  13. 	Run()
  14. 	Send()
  15. }
  17. func calculator(a int, b int) {
  18. 	fmt.Printf("ModelB %d\n", a+b)
  19. }
  21. func (bus *Bus) Receive() {
  22. 	err := bus.EventBus.Subscribe("testMessageFromA", calculator)
  23. 	if err != nil {
  24. 		fmt.Printf("Error Receiving message...")
  25. 	}
  26. }
  28. func (bus *Bus) Send() {
  29. 	bus.EventBus.Publish("testMessageFromB", 33, 60)
  30. }
英文:

I am trying to learn GO and in doing so trying different concepts. Right now I am trying a PubSub approach, but within the application. I have an EventBus and I amd trying to pass the instance via Dependency Injection. However when I run the application nothing happens.

main

  1. package main
  3. import (
  4. 	"github.com/asaskevich/EventBus"
  5. 	modelA "interfaces/internal/modelA"
  6. 	modelB "interfaces/internal/modelB"
  7. )
  9. func main() {
  10. 	bus := EventBus.New()
  12. 	a := &modelA.Bus{EventBus: bus}
  13. 	a.Send()
  15. 	b := &modelB.Bus{
  16. 		EventBus: bus,
  17. 	}
  18. 	b.Receive()
  20. }

internal/modelA

  1. package modelA
  3. import (
  4. 	"fmt"
  5. 	"github.com/asaskevich/EventBus"
  6. )
  8. type Bus struct {
  9. 	EventBus EventBus.Bus
  10. }
  12. type ModelAService interface {
  13. 	Run()
  14. 	Send()
  15. }
  17. func calculator(a int, b int) {
  18. 	fmt.Printf("ModelA "+"%d\n", a+b)
  19. }
  21. func (bus *Bus) Receive() {
  22. 	err := bus.EventBus.Subscribe("testMessageFromB", calculator)
  23. 	if err != nil {
  24. 		fmt.Printf("Error Receiving message...")
  25. 	}
  26. }
  28. func (bus *Bus) Send() {
  29. 	bus.EventBus.Publish("testMessageFromA", 33, 33)
  30. }

internal/modelB

  1. package modelB
  3. import (
  4. 	"fmt"
  5. 	"github.com/asaskevich/EventBus"
  6. )
  8. type Bus struct {
  9. 	EventBus EventBus.Bus
  10. }
  12. type ModelBService interface {
  13. 	Run()
  14. 	Send()
  15. }
  17. func calculator(a int, b int) {
  18. 	fmt.Printf("ModelB "+"%d\n", a+b)
  19. }
  21. func (bus *Bus) Receive() {
  22. 	err := bus.EventBus.Subscribe("testMessageFromA", calculator)
  23. 	if err != nil {
  24. 		fmt.Printf("Error Receiving message...")
  25. 	}
  26. }
  28. func (bus *Bus) Send() {
  29. 	bus.EventBus.Publish("testMessageFromB", 33, 60)
  30. }

答案1

得分: 2

你需要首先订阅一个主题，然后发布（执行为主题定义的回调函数）。

可以尝试以下代码：

  1. func main() {
  2.     bus := EventBus.New()
  4.     a := &modelA.Bus{EventBus: bus}
  5.     b := &modelB.Bus{EventBus: bus}
  7.     b.Receive() // 订阅
  8.     a.Send()    // 发布
  9.     // 取消订阅
  10. }

还可以参考示例：

  1. func calculator(a int, b int) {
  2.     fmt.Printf("%d\n", a + b)
  3. }
  5. func main() {
  6.     bus := EventBus.New()
  7.     bus.Subscribe("main:calculator", calculator)
  8.     bus.Publish("main:calculator", 20, 40)
  9.     bus.Unsubscribe("main:calculator", calculator)
  10. }

我的调试结构和输出如下：

全局事件总线（Global EventBus）在Go语言中的实现

注释：
为了清晰起见，你可以将b.Receive()重命名为b.Subscribe()，将a.Send()重命名为a.Publish()。

另请参阅gRPC：

全局事件总线（Global EventBus）在Go语言中的实现

英文:

You need to first Subscribe to a topic
then Publish (executes callback defined for a topic).

Try something like this:

  1. func main() {
  2.     bus := EventBus.New()
  4.     a := &modelA.Bus{EventBus: bus}
  5.     b := &modelB.Bus{EventBus: bus}
  7. 	b.Receive() // Subscribe
  8. 	a.Send()    // Publish
  9.     // Unsubscribe
  10. }

Also see the example:

  1. func calculator(a int, b int) {
  2. 	fmt.Printf("%d\n", a + b)
  3. }
  5. func main() {
  6. 	bus := EventBus.New();
  7. 	bus.Subscribe("main:calculator", calculator);
  8. 	bus.Publish("main:calculator", 20, 40);
  9. 	bus.Unsubscribe("main:calculator", calculator);
  10. }

My debugging structure and output:
全局事件总线（Global EventBus）在Go语言中的实现

Footnotes:
You may rename b.Receive() to b.Subscribe()
and a.Send() to a.Publish() for clarity.

See also gRPC:

全局事件总线（Global EventBus）在Go语言中的实现

huangapple
  • 本文由 发表于 2022年4月24日 18:29:13
  • 转载请务必保留本文链接：https://go.coder-hub.com/71987522.html
  • go
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