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Camille
Camille

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Channel push non blocking in GoLang

By default push operations to golang channel will block once the channel is full and wait that an other go routine will consume a message from the channel.

The following example will block after 3 messages queued in the channel, and since no other go routine is running it will crash with a dead lock error:

package main

import "fmt"

func main() {
    ch := make(chan string, 3)

    for i := 0; i < 10; i++ {
        ch <- "hello"
        fmt.Println("Pushed a message to the channel")
    }
}
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To avoid blocking the execution of your application you can handle the case of a full channel by using select:

package main

import "fmt"

func main() {
    ch := make(chan string, 3)

    for i := 0; i < 10; i++ {
        select {
        case ch <- "hello":
            fmt.Println("Pushed a message to the channel")
        default:
            fmt.Println("WARN: The channel is full")
        }
    }
}

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This way you can easily decide to ignore the message or handle this problem an other way than blocking the current go routine.

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