Golang development: Mastering concurrent programming based on message passing

Golang development: Mastering concurrent programming based on message passing requires specific code examples

Introduction:
Golang, as an efficient and concise programming language, provides It has rich concurrent programming features, of which concurrent programming based on message passing is a unique part. In this article, we will discuss message passing-based concurrent programming in Golang in detail and give specific code examples to help readers better understand and master this technology.

1. What is concurrent programming based on message passing?
In traditional concurrent programming, threads in the program use shared memory to communicate, which can easily lead to problems such as deadlocks and race conditions. Concurrent programming based on message passing uses messages to communicate between different threads. The threads are relatively independent and avoid the problem of shared memory.

In Golang, concurrent programming based on message passing mainly relies on goroutine and channel. A goroutine is a lightweight thread that can be managed by the Go runtime scheduler. Channel is a data structure used to transfer messages between goroutines.

2. Use channels for message transmission
In Golang, by creating channel objects, messages can be transmitted between different goroutines. The following is a simple sample code that shows how to use channels for message passing:

func main() {
    // 创建一个int类型的channel
    ch := make(chan int)
    
    // 启动一个goroutine发送消息
    go func() {
        ch <- 1
    }()
    
    // 接收goroutine发送的消息
    num := <-ch
    fmt.Println(num)
}

In the above example, a channel object of type int ch is first created. Next, use ch in a new goroutine to send a message to the channel. Finally, receive the message from the channel through the <code>num := statement and print it out.

3. Channel blocking and non-blocking operations
When using channels for message transmission, there are two basic operation methods: blocking and non-blocking.

Blocking operation means that when no message is available in the channel, the receiving operation will block until a message is available. Likewise, send operations block until a receiver receives the message.

Non-blocking operation means that when no message is available in the channel, the receiving operation will immediately return a null value. The send operation will return an error immediately when the channel is full.

The following is a sample code that shows how to use blocking and non-blocking operations:

func main() {
    ch := make(chan int, 1)
    ch <- 1 // 向channel发送消息
    
    // 阻塞操作
    num := <-ch
    fmt.Println(num)
    
    // 非阻塞操作
    select {
    case num := <-ch:
        fmt.Println(num)
    default:
        fmt.Println("channel中没有消息可用")
    }
}

In the above example, a channel object with a buffer size of 1 is first created and passed to It sent a message. Next, the effects of blocking and non-blocking operations are demonstrated through receive operations and non-blocking select statements.

4. Use select statements for multiplexing
The select statement in Golang provides a way to select an available channel from multiple channels for operation. Below is a sample code that shows how to use select statements for multiplexing:

func main() {
    ch1 := make(chan int)
    ch2 := make(chan int)
    
    go func() {
        ch1 <- 1
    }()
    
    go func() {
        ch2 <- 2
    }()
    
    // 使用select语句选择可用的channel
    select {
    case num := <-ch1:
        fmt.Println(num)
    case num := <-ch2:
        fmt.Println(num)
    }
}

In the above example, two different channel objects ch1 and are first created ch2. Then send messages to ch1 and ch2 respectively. Finally, select available channels by using the select statement and print out the corresponding message.

5. Summary
This article introduces the concepts and features of concurrent programming based on message passing in Golang, and gives specific code examples. By using goroutines and channels to implement message passing, relatively independent concurrent operations are achieved between multiple goroutines. At the same time, through the use of blocking and non-blocking operations and select statements, the flexibility and maintainability of concurrent programming are further improved.

I hope that through the introduction of this article, readers can better understand and master message passing-based concurrent programming in Golang, give full play to the advantages of Golang concurrent programming, and improve the performance and reliability of the program.

Reference materials:

1. Golang official documentation (https://golang.org/doc/)
2. Go concurrent programming practice (https://www. imooc.com/learn/927)

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