Golang framework and Elixir framework: a unique perspective on concurrent programming

Golang’s Goroutine and Elixir’s Erlang VM provide unique concurrent programming models. Golang uses lightweight parallel threads (goroutines) to efficiently schedule tasks in a single process, and Elixir is based on the Erlang virtual machine (BEAM) to express concurrency through a process mechanism. In practical cases, Goroutine or Erlang VM can be used to execute crawling tasks in parallel to improve efficiency.

Golang framework and Elixir framework: a unique perspective on concurrent programming

In modern software development, concurrent programming has become an essential technology. Golang and Elixir are two popular programming languages ​​that offer unique concurrent programming models. In this tutorial, we will explore these models and demonstrate them with practical examples.

Golang's Goroutine

Golang provides a lightweight parallel thread called a goroutine, which allows concurrent execution of tasks without blocking the function that calls it. Goroutine uses the coroutine mechanism to efficiently schedule multiple concurrent operations in a single process.

package main

import (
    "fmt"
    "runtime"
    "time"
)

func main() {
    // 创建一个 goroutine
    go func() {
        for i := 0; i < 10; i++ {
            fmt.Println("goroutine:", i)
        }
    }()

    // 主线程继续执行
    for i := 0; i < 10; i++ {
        fmt.Println("main:", i)
    }

    // 确保 goroutine 完成后再退出
    time.Sleep(1 * time.Second)

    // 输出
    // goroutine: 0
    // main: 0
    // goroutine: 1
    // main: 1
    // ...
    // goroutine: 9
    // main: 9
}

Elixir’s Erlang VM

Elixir is based on the Erlang Virtual Machine (BEAM), a highly concurrent and fault-tolerant runtime environment. BEAM implements Erlang, Elixir, and other BEAM-based languages ​​and provides a mechanism called processes to express concurrency.

defmodule MyModule do
  def main do
    # 创建一个进程并向其发送消息
    spawn(fn ->
      receive do
        {_, msg} ->
          IO.println("进程收到消息: #{msg}")
      end
    end)

    # 主进程继续执行
    for i <- 1..10 do
      send(self(), {self(), "消息 #{i}"})
    end
  end
end

MyModule.main

Practical case: Parallel crawling

Using Golang's Goroutine or Elixir's Erlang VM, we can execute crawling tasks in parallel. The following is an example implemented using Golang:

package main

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

func main() {
    // 创建一个同步锁来维护结果
    var lock sync.Mutex
    var wg sync.WaitGroup

    // 创建一个通道来存储结果
    results := make(chan string)

    // 爬取 URL 列表
    urls := []string{"www.google.com", "www.amazon.com", "www.facebook.com"}
    startTime := time.Now()

    for _, url := range urls {
        // 创建一个 goroutine 来爬取每个 URL
        wg.Add(1)

        go func(url string) {
            defer wg.Done()

            // 发送 HTTP 请求
            resp, err := http.Get(url)
            if err != nil {
                results <- fmt.Sprintf("爬取失败: %s", err)
                return
            }

            // 读取并打印响应内容
            contents, err := ioutil.ReadAll(resp.Body)
            resp.Body.Close()
            if err != nil {
                results <- fmt.Sprintf("读取内容失败: %s", err)
                return
            }

            // 使用锁来安全地存储结果
            lock.Lock()
            defer lock.Unlock()
            results <- fmt.Sprintf("爬取成功: %s\n内容:\n%s", url, contents)
        }(url)
    }

    // 等待所有 goroutine 完成
    wg.Wait()
    close(results)

    // 打印结果
    for result := range results {
        fmt.Println(result)
    }

    fmt.Printf("爬取完成，用时：%v\n", time.Since(startTime))
}

Conclusion

Golang’s Goroutine and Elixir’s Erlang VM provide unique and powerful concurrent programming models. By using goroutines and processes, we can efficiently execute parallel tasks and build high-performance applications.

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