Summary of Golang concurrent programming experience: best practices for elegant application of Goroutines

Golang Concurrent Programming Experience Summary: Best Practices for Elegant Application of Goroutines

Introduction:
In today's highly concurrent Internet era, writing effective parallel programs has become more and more important. Golang, as a language focused on concurrent programming, provides some powerful tools to handle a large number of concurrent tasks. The most important of them are Goroutines.

Goroutines are the core component of Golang's concurrency model, which allow us to create lightweight threads at very low cost. By using Goroutines properly, we can write parallel programs elegantly and improve performance and reliability. This article will summarize some best practices for elegantly applying Goroutines to help readers better master concurrent programming.

1. Basic Concepts
Before we begin, let’s review some basic concepts. Goroutine is a lightweight thread. Golang manages and schedules these Goroutines through runtime. With the keyword "go", we can create a new Goroutine in the program. When the Goroutine's task is completed, it will automatically exit.

2. How to use Goroutines
The following is a simple example showing how to use Goroutines to download multiple files at the same time:

package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    urls := []string{"https://example.com/file1.txt", "https://example.com/file2.txt", "https://example.com/file3.txt"}

    for _, url := range urls {
        go func(u string) {
            res, err := http.Get(u)
            if err != nil {
                fmt.Println("Error:", err)
                return
            }
            defer res.Body.Close()

            content, err := ioutil.ReadAll(res.Body)
            if err != nil {
                fmt.Println("Error:", err)
                return
            }

            fmt.Printf("Downloaded %s: %d bytes
", u, len(content))
        }(url)
    }

    // 在这里添加等待所有Goroutines完成的逻辑
    // ...

    fmt.Println("All downloads completed")
}

In the above code, we use a for loop Iterates through the list of files that need to be downloaded, and creates a new Goroutine using an anonymous function in each loop. Each Goroutine is responsible for downloading the corresponding file and printing the download results.

3. Wait for all Goroutines to complete
In actual applications, we usually need to wait for all Goroutines to complete before performing other operations. Fortunately, Golang provides a simple and effective way to achieve this purpose, which is to use WaitGroup in the sync package:

package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
    "sync"
)

func main() {
    urls := []string{"https://example.com/file1.txt", "https://example.com/file2.txt", "https://example.com/file3.txt"}
    var wg sync.WaitGroup

    for _, url := range urls {
        wg.Add(1) // 每个Goroutine开始时增加WaitGroup的计数器

        go func(u string) {
            defer wg.Done() // Goroutine完成时减少WaitGroup的计数器

            res, err := http.Get(u)
            if err != nil {
                fmt.Println("Error:", err)
                return
            }
            defer res.Body.Close()

            content, err := ioutil.ReadAll(res.Body)
            if err != nil {
                fmt.Println("Error:", err)
                return
            }

            fmt.Printf("Downloaded %s: %d bytes
", u, len(content))
        }(url)
    }

    wg.Wait() // 等待所有Goroutines完成

    fmt.Println("All downloads completed")
}

In the above code, we use sync.WaitGroup to synchronize all Goroutines . At the beginning of each Goroutine, we increment the counter value via wg.Add(1). At the end of the Goroutine, we decrement the counter by defer wg.Done(). Finally, we use wg.Wait() to block the main thread until all Goroutines have completed.

Summary:
In concurrent programming, it is crucial to use Goroutines reasonably and elegantly. Through reasonable concurrency design and reasonable resource management, we can improve the performance and reliability of the program. This article introduces some best practices for elegantly applying Goroutines, hoping to be helpful to readers in Golang concurrent programming.

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