如何检查是否有 wget 实例正在运行

Question

我有这个 php 脚本，每次使用 & 调用它时都会运行 wget 的 fork 进程：

wget http://myurl?id='.$insert_id .' -O ./images/'. $insert_id.' > /dev/null 2>&1 &

但是我如何检查是否已经有一个 wget 进程正在进行中，如果有，不要运行另一个？

Answer 1

此代码用于控制运行过程（在我的例子中是 php 脚本）。

您可以随意取出您需要的零件并随意使用。

class Process
{
  private $processName;
  private $pid;

  public $lastMsg;

  public function __construct($proc)
  { 
    $this->processName = $proc;
    $this->pid = 0;
    $this->lastMsg = "";
  }

  private function update()
  { 
    $output = array();
    $cmd = "ps aux | grep '$this->processName' | grep -v 'grep' | awk '{ print $2; }' | head -n 1";
    exec($cmd, $output, $rv);

    if ($rv == 0 && isset($output[0]) && $output[0] != "")
      $this->pid = $output[0];
    else
      $this->pid = false;

    return;
  }

  public function start()
  { 
    // if process isn't already running,
    if ( !$this->is_running() )
    { 
      // call exec to start php script
      $op = shell_exec("php $this->processName &> /dev/null & echo $!");

      // update pid
      $this->pid = $op;
      return $this->pid;
    }
    else
    { 
      $this->lastMsg = "$this->processName already running";
      return false;
    }
  }
  public function is_running()
  {
    $this->update();

    // if there is no process running
    if ($this->pid === false)
    {
      $this->lastMsg = "$this->processName is not running";
      return false;
    }
    else
    {
      $this->lastMsg = "$this->processName is running.";
      return true;
    }
  }

  public function stop()
  {
    $this->update();

    if ($this->pid === false)
    {
      return "not running";
    }
    else
    {
      exec('kill ' . $this->pid, $output, $exitCode);
      if ($exitCode > 0)
        return "cannot kill";
      else
        return true;
    }
  }

}