利用Cron Jobs实现PHP脚本对后台进程的动态控制

{
    "current_value": 0,
    "target_value": 100,
    "interval_ms": 10,
    "is_running": false,
    "last_updated": 0
}

# 每分钟执行一次 worker.php 脚本
* * * * * /usr/bin/php /path/to/your/worker.php >> /var/log/worker.log 2>&1

<?php
// worker.php

// 1. 实现单例模式 (使用文件锁)
$lockFile = '/tmp/worker.lock';
$fp = fopen($lockFile, 'c');
if (!flock($fp, LOCK_EX | LOCK_NB)) {
    // 另一个实例正在运行，退出
    echo "Worker already running. Exiting.\n";
    exit;
}

// 确保在脚本结束时释放锁
register_shutdown_function(function() use ($fp, $lockFile) {
    flock($fp, LOCK_UN);
    fclose($fp);
    // 可选：删除锁文件
    // unlink($lockFile); 
});

// 2. 主循环：持续运行，直到任务完成或被外部停止
while (true) {
    // 3. 读取配置 (模拟从 config.json 读取)
    $configFilePath = '/path/to/your/config.json';
    if (!file_exists($configFilePath)) {
        echo "Config file not found. Exiting.\n";
        break; // 或等待文件出现
    }
    $config = json_decode(file_get_contents($configFilePath), true);

    if (!$config || !isset($config['is_running']) || !$config['is_running']) {
        echo "Task not running or config invalid. Waiting...\n";
        sleep(5); // 如果任务未运行，则等待一段时间再检查
        continue;
    }

    $currentValue = $config['current_value'];
    $targetValue = $config['target_value'];
    $intervalMs = $config['interval_ms'];

    if ($currentValue >= $targetValue) {
        // 任务已完成，更新状态并退出循环
        $config['is_running'] = false;
        $config['current_value'] = 0; // 重置
        file_put_contents($configFilePath, json_encode($config, JSON_PRETTY_PRINT));
        echo "Task completed. Exiting worker loop.\n";
        break; 
    }

    // 4. 执行计时/计数逻辑
    echo "Current: {$currentValue}, Target: {$targetValue}, Interval: {$intervalMs}ms\n";
    $currentValue++;

    // 5. 更新状态
    $config['current_value'] = $currentValue;
    $config['last_updated'] = time();
    file_put_contents($configFilePath, json_encode($config, JSON_PRETTY_PRINT));

    // 6. 毫秒级延时
    usleep($intervalMs * 1000); // usleep 接受微秒
}

echo "Worker script finished.\n";
?>

<?php
// controller.php?req=10  (设置目标值为10)
// controller.php?req=0   (停止任务)

$configFilePath = '/path/to/your/config.json';

// 初始化或读取配置
if (!file_exists($configFilePath)) {
    $config = [
        "current_value" => 0,
        "target_value" => 0,
        "interval_ms" => 10, // 默认10毫秒
        "is_running" => false,
        "last_updated" => 0
    ];
} else {
    $config = json_decode(file_get_contents($configFilePath), true);
}

$requestValue = isset($_GET['req']) ? (int)$_GET['req'] : null;

if ($requestValue !== null) {
    if ($requestValue > 0) {
        $config['target_value'] = $requestValue;
        $config['current_value'] = 0; // 每次新请求重置计数
        $config['is_running'] = true;
        echo "Task updated: target set to {$requestValue}, started.\n";
    } else { // req=0 表示停止任务
        $config['is_running'] = false;
        $config['current_value'] = 0;
        $config['target_value'] = 0;
        echo "Task stopped.\n";
    }
    $config['last_updated'] = time();
    file_put_contents($configFilePath, json_encode($config, JSON_PRETTY_PRINT));
} else {
    echo "No 'req' parameter provided. Current config: " . json_encode($config) . "\n";
}

?>

# /path/to/your/cron_entry.sh
#!/bin/bash

LOCK_FILE="/tmp/worker.lock"
WORKER_SCRIPT="/path/to/your/worker.php"
LOG_FILE="/var/log/worker.log"

# 使用 pidof 检查进程是否已在运行
# 或者直接依赖 worker.php 内部的文件锁机制

if [ ! -f "$LOCK_FILE" ]; then
    # 如果锁文件不存在，则启动 worker 脚本
    # 注意：这里假设 worker.php 会在内部处理其自身的长期运行和单例
    /usr/bin/php "$WORKER_SCRIPT" >> "$LOG_FILE" 2>&1 &
    echo "Started worker.php at $(date)" >> "$LOG_FILE"
else
    echo "worker.php is already running (lock file exists) at $(date)" >> "$LOG_FILE"
fi

* * * * * /path/to/your/cron_entry.sh