An example introduces golang’s method of achieving millions of concurrent requests

With the rapid development of the Internet, the demand for high concurrency is getting higher and higher. How to improve the concurrency of the system has become an important issue explored by programmers. In the field of programming languages, golang has become a popular high-concurrency programming language because of its inherent concurrency characteristics and excellent performance. Next, we will introduce how to use golang to achieve millions of concurrent requests based on actual cases.

First of all, for beginners who have just come into contact with golang, goroutine and channel are the two most important concepts, and they are also the core of golang's high concurrency. Goroutine is a lightweight thread that does not occupy too many resources and can execute multiple goroutines at the same time to achieve efficient concurrent operations. Channel is a pipeline used for communication between goroutines, which can realize data transmission and synchronization operations.

Next, we use a simple example to understand the implementation method of golang's goroutine and channel. First, we write a simple HTTP server that can listen to requests and return responses. The code is as follows:

package main

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

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        io.WriteString(w, "Hello, World!\n")
    })
    log.Fatal(http.ListenAndServe(":8080", nil))
}

Next, we use golang's goroutine and channel to achieve millions of concurrent requests. First, we need to open multiple goroutines to send requests. The code is as follows:

package main

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

func worker(url string, ch chan<- string, wg *sync.WaitGroup) {
    defer wg.Done()
    resp, err := http.Get(url)
    if err != nil {
        log.Fatal(err)
    }
    defer resp.Body.Close()
    body, err := io.ReadAll(resp.Body)
    if err != nil {
        log.Fatal(err)
    }
    ch <- string(body)
}

func main() {
    var wg sync.WaitGroup
    ch := make(chan string)
    for i := 0; i < 1000000; i++ {
        wg.Add(1)
        go worker("https://www.example.com", ch, &wg)
    }
    go func() {
        wg.Wait()
        close(ch)
    }()
    for resp := range ch {
        fmt.Println(resp)
    }
}

In the above code, we define the worker function for sending HTTP requests. In the main function, we open 1 million goroutines. Each goroutine will call the worker function to request the https://www.example.com interface and put the return result into channel ch. In the main goroutine, we use a for loop to traverse the response values ​​in channel ch and output them to the console.

It should be noted that since 1 million goroutines are opened, if no restrictions are imposed, the system may crash. Therefore, in an actual production environment, we need to appropriately control the number of goroutines to avoid excessive pressure on system resources.

To summarize, the goroutine and channel mechanisms provided by golang can easily implement high-concurrency operations and greatly improve the performance of the system. Through the above simple example, we can have a preliminary understanding of golang's method of achieving millions of concurrent requests. However, in the actual production environment, it is necessary to combine business scenarios and system resources to appropriately control the number of goroutines and the scale of concurrent requests, so as to achieve optimal performance results. .

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