How to use Swoole to implement multi-process concurrent programming

Swoole is a high-performance network communication framework for PHP, which can help us achieve high-performance network concurrent programming. One of the most important features is its support for multi-processes, which allows us to implement high-concurrency network programming through multi-processes.

This article will introduce how to use Swoole to implement multi-process concurrent programming, including multi-process creation, communication, synchronization, etc., and will provide specific code examples.

1. Creation of multiple processes
   In Swoole, we can use the swoole_process class to create a child process. The following is a simple example:

$process = new swoole_process(function(swoole_process $process) {
    // 子进程的逻辑代码
    $process->write("Hello world!
"); // 向主进程发送消息
    $process->exit();
});

$process->start();

// 父进程接收子进程消息
$msg = $process->read();
echo $msg;

In this example, a subprocess is created using the constructor of the swoole_process class, and the logic code of the subprocess is implemented through a callback function. The start() method starts the child process, and then the parent process receives the message sent by the child process through the read() method.

2. Multi-process communication
   In Swoole, communication between multiple processes can use various methods such as pipes, message queues, and shared memory. The more commonly used one is the pipeline method. The following is an example of using pipes for communication:

$process = new swoole_process(function(swoole_process $process) {
    $process->write("Hello world!
");
    $data = $process->read();
    echo "Child process received: " . $data;
    $process->exit();
}, true); // 启用管道通信模式

$process->start();

$msg = $process->read();
echo $msg;
$process->write("I am the parent process.
");
$process->wait(); // 等待子进程退出

In this example, we call the constructor of the swoole_process class and pass in a Boolean type parameter to indicate that the pipe communication mode is enabled. Then call the write() method in the parent process to send messages to the child process, and receive messages from the child process through the read() method. In the child process, the write() method is also used to send messages to the parent process, and the read() method is used to receive messages from the parent process.

3. Multi-process synchronization
   In multi-process programming, synchronization issues must be considered. Swoole provides a variety of ways to achieve synchronization between multiple processes, the more commonly used of which is to use semaphores and locks. The following is an example of using locks for synchronization:

$lock = new swoole_lock(SWOOLE_MUTEX); // 创建一个互斥锁

$process1 = new swoole_process(function(swoole_process $process) use ($lock) {
    $lock->lock(); // 加锁
    echo "Process 1 acquired the lock.
";
    sleep(1);
    $lock->unlock(); // 解锁
});

$process2 = new swoole_process(function(swoole_process $process) use ($lock) {
    $lock->lock(); // 加锁
    echo "Process 2 acquired the lock.
";
    sleep(1);
    $lock->unlock(); // 解锁
});

$process1->start();
$process2->start();

$process1->wait();
$process2->wait();

In this example, we use the swoole_lock class to create a mutex lock and lock and unlock it in the two child processes respectively. In the parent process, we call the wait() method to wait for the two child processes to complete execution.

4. Complete example
   The following is a complete example that demonstrates how to use Swoole to implement multi-process concurrent programming, including creating multiple child processes, communicating through pipes, using semaphores for synchronization, etc.

$workers = [];
$worker_num = 3;

for ($i = 0; $i < $worker_num; $i++) {
    $process = new swoole_process(function (swoole_process $worker) {
        $num = rand(1, 100);
        echo "Worker {$worker->pid} is calculating the square of $num...
";
        sleep(1);
        $worker->write($num * $num);
        $worker->exit();
    }, true);

    $pid = $process->start();
    $workers[$pid] = $process;
}

// 父进程接收子进程返回的计算结果
foreach ($workers as $pid => $process) {
    $result = $process->read();
    echo "Worker $pid calculated the result: $result
";
}

echo "All workers have completed their tasks.
";

In this example, we create 3 sub-processes, each sub-process randomly generates a number, calculates the square of this number and returns it. The parent process receives the results returned by all child processes through a loop and prints them to the console. Eventually, the parent process prints a message that all tasks are completed.

Summary
Swoole is a powerful, high-performance network communication framework that provides good support for multi-process programming. When using Swoole for multi-process programming, you need to consider various issues such as process creation, communication, and synchronization. This article provides specific code examples, hoping to help readers better understand and master Swoole's multi-process programming skills.

The above is the detailed content of How to use Swoole to implement multi-process concurrent programming. For more information, please follow other related articles on the PHP Chinese website!