[golang] use select {}

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scene

Sometimes we need to keep the application from quitting , Always running in the background .

Where is the effect of permanent blockage ？ When we develop a program ,main The function must not exit before the subprocess finishes its work , Otherwise, all sub processes will be forced to quit . The service was forced to stop .

You usually use channel, Here's an introduction select{}

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Code

func main() {
    
    for i := 0; i < 10; i++ {
     // start-up 20 A coroutine processes messages in the message queue 
        c := consumer.New()
        go c.Start()
    }
    select {
    } //  Blocking 
}

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Explain

select yes Go A control structure in , Similar to... For communication switch sentence .

select Random execution A runnable case. without case Can run , It will block , Until there is case Can run . A default clause should always run .

package main

import "fmt"

func main() {
    
	ch1 := make(chan int, 1)
	ch2 := make(chan int, 1)
	ch1 <- 1
	ch2 <- 1

	select {
    
	case <-ch1:
		fmt.Println("ch1 pop one element")
	case <-ch2:
		fmt.Println("ch2 pop one element")
	/*  You can define any number of  case */
	default: /*  Optional  */
		fmt.Println("default! ")
	}
}

Infinite loop

select{
    }

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