How to close goroutine in golang (three methods)

Golang’s goroutine is one of its powerful concurrency mechanisms. The advantages of goroutine are that they are lightweight, efficient, and easy to create and control. But at the same time, how to shut down goroutine reasonably is a very important issue.

Why should we close goroutine?

The creation of goroutine is very easy, but unreasonable use will lead to a waste of resources, especially for long-running goroutine. If a goroutine continues to run until the program ends, system resources will be occupied, which may cause the program to crash and affect system performance.

So, we need to close the goroutine. Normally, the reasons why goroutine needs to be closed are:

1. The goroutine needs to be closed when the program exits.
2. goroutine needs to be closed after execution to avoid wasting system resources.
3. When an error occurs, the goroutine needs to be closed.

How to close goroutine?

The GO language provides multiple mechanisms to close goroutine:

1. Use channel

You can use channel to close goroutine. Create a channel, and when the goroutine needs to be closed, send data to the channel. After the goroutine reads the data, it can exit normally. For example:

func worker(stopCh chan struct{}) {
    for {
        select {
            // do something...
            case <-stopCh:
                return
        }
    }
}

stopCh := make(chan struct{})
go worker(stopCh)

// 关闭 goroutine
close(stopCh)

2. Use context

The context package provides a more elegant way to shut down goroutines. You can create a context.Context and use the WithCancel or WithTimeout function to cancel the context when necessary to close the goroutine. For example:

func worker(ctx context.Context) {
    for {
        select {
            // do something...
            case <-ctx.Done():
                return
        }
    }
}

ctx, cancel := context.WithCancel(context.Background())
go worker(ctx)

// 关闭 goroutine
cancel()

3. Use sync.WaitGroup

The sync package provides WaitGroup, which can wait for the completion of goroutine. You can add a Done method that is called at the end of the goroutine execution. If all goroutines have finished executing, you can use Wait to block the wait. For example:

func worker(wg *sync.WaitGroup) {
    defer wg.Done()
    // do something...
}

var wg sync.WaitGroup
wg.Add(1)
go worker(&wg)

// 等待 goroutine 执行结束
wg.Wait()

Notes on closing goroutine

1. Do not close goroutine directly

Normally, do not close goroutine directly, otherwise resources may occur Issues such as leaks and race conditions. You need to use channel, context or WaitGroup to close the goroutine.

2. Design goroutine to be closable

When designing a goroutine, it is best to design it to be closable. If a long-running goroutine is designed to be non-closable, it may not be able to be closed, causing problems. So be aware of this when writing code and using goroutines.

3. Use system resources with caution

System resources are limited, and too many goroutines may occupy too many system resources, thus affecting system performance. Therefore, when using goroutines, be sure to use system resources carefully and ensure that they are released correctly.

Summary

Goroutine is a highlight in Golang because it is lightweight, efficient, and easy to use. However, this feature also needs to be used with caution. Properly closing goroutine is a skill that must be mastered in Golang development. We can use mechanisms such as channel, context or WaitGroup to close goroutine to avoid resource leaks and other problems.

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