Health.php

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<?php
 
namespace Rsi\Fred;
 
/**
 *  Health checks.
 */
class Health extends Component{
 
  public $retentionPeriod = 28; //!< Number of days to keep data.
  public $interval = 60; //!< Minimal mail interval (minutes).
  public $from = null; //!< Sender (defaults to default From address).
  public $to = null; //!< Send mail to this address (or array for multiple; defaults to default From address).
  public $subject = 'Health warning for *'; //!< Subject for the mail (an asterisk is replaced with the host name).
  public $template = null; //!< Template for mail message.
 
  public $graphFont = 3;
  public $graphColors = [[200,0,0],[0,200,0],[0,0,200],[200,200,0],[0,200,200],[200,0,200],[100,0,0],[0,100,0],[0,0,100],[100,100,0],[0,100,100],[100,0,100]];
  public $graphIntervalFactors = [2.5,2,2];
  public $graphSecondaryFactor = 5;
 
  protected $_checks = null; //!< Available checks (key = name, value = \\Rsi\\Fred\\Health\\Check).
 
  /**
   * Save the check results.
   * @param array $data  Key = check name, value = check result.
   */
  protected function save($data){
  }
 
  protected function send($messages){
    $table = "<table>\n";
    foreach($messages as $name => $message)
      $table .= '<tr><td>' . htmlspecialchars($name) . '</td><td>' . htmlspecialchars($message) . "</td></tr>\n";
    $table .= "</table>";
    return $this->_log->component('mail')->send(
      $this->from,
      $this->to ?: ini_get('sendmail_from'),
      str_replace('*',$host = \Rsi\Http::host(),$this->subject),
      strtr($this->template,[
        '[time]' => date('Y-m-d H:i:s'),
        '[host]' => $host,
        '[ip]' => $_SERVER['SERVER_ADDR'] ?? gethostbyname($host),
        '[messages]' => $table
      ]) ?: $table,
      true
    );
  }
  /**
   * Perform all checks.
   */
  public function check(){
    $messages = $data = [];
    foreach($this->checks as $name => $check){
      $data[$name] = $check->check($message);
      if($message) $messages[$name] = $message;
    }
    $this->save($data);
    if($messages) $this->send($messages);
  }
  /**
   * Get available data.
   * @param int $since  Return data since this timestamp (empty = all).
   * @return array  Key = timestamp, value = record with key = check name, value = check result.
   */
  public function data($since = null){
    return [];
  }
  /**
   * Create a graph with all data points.
   * @param int $width  Width of image (pixels).
   * @param int $height  Height of image (pixels).
   * @param int $since  Use data since this timestamp (empty = all).
   * @return resource  Image resource.
   */
  public function graph($width = 640,$height = 480,$since = null){
    $image = imagecreate($width,$height);
    imagecolorallocate($image,255,255,255);
    if(count($data = $this->data($since)) > 1){
      $color_border = imagecolorallocate($image,0,0,0);
      $color_grid = imagecolorallocate($image,200,200,200);
//TODO: bereik van waarden analyseren en dan (evt.) over 2 assen verdelen ("grote waarden" / "kleine waarden") (???)
      $value_min = $value_max = 0;
      $font_width = imagefontwidth($this->graphFont);
      $font_height = imagefontheight($this->graphFont);
      $names = [];
      foreach($data as $record) foreach($record as $name => $value) $names[$name] = max($names[$name] ?? 0,$value);
      $value_max = max($names);
      $graph_height = $height - 2 * $font_height;
      $interval_min = 2 * $font_height * ($value_max - $value_min) / $graph_height;
      $index = 0;
      $value_interval = 0.001;
      while($value_interval < $interval_min) $value_interval *= $this->graphIntervalFactors[$index++ % count($this->graphIntervalFactors)];
      $value_max = ceil($value_max / $value_interval) * $value_interval;
      foreach($names as $name => $name_max) $names[$name] = $name_max <= $value_max / $this->graphSecondaryFactor;
      $value_chars = max(5,strlen($value_max) + ($decimals = ($i = strpos($value_interval,'.')) ? strlen($value_interval) - $i : 0));
      $graph_width = $width - $font_width * $value_chars;
      if(($graph_width > 50) && ($graph_height > 50)){
        $value = $value_min;
        while(($value += $value_interval) < $value_max){
          $y = round(($value_max - $value) / ($value_max - $value_min) * $graph_height);
          imageline($image,$width - $graph_width,$y,$width,$y,$color_grid);
          $value_str = number_format($value,max(0,$decimals - 1));
          imagestring($image,$this->graphFont,$width - $graph_width - strlen($value_str) * $font_width,$y - $font_height / 2,$value_str,$color_border);
        }
        $times = array_keys($data);
        $time_min = floor(min($times) / 86400) * 86400;
        $time_max = ceil(max($times) / 86400) * 86400;
        $time_interval = ceil(11 * $font_width * ($time_max - $time_min) / $graph_width / 86400) * 86400;
        $time = $time_min;
        do{
          $x = $width - round(($time_max - $time) / ($time_max - $time_min) * $graph_width);
          imageline($image,$x,0,$x,$graph_height,$color_grid);
          if(!(($time - $time_min) % $time_interval)) imagestring($image,$this->graphFont,$x - 5 * $font_width,$graph_height,date('Y-m-d',$time),$color_border);
        }
        while(($time += 86400) < $time_max);
        $legend_size = $font_height;
        $legend_x = round((
          $width -
          (strlen(implode(array_keys($names))) + count(array_filter($names)) * (strlen($this->graphSecondaryFactor) + 1)) * $font_width -
          count($names) * $legend_size * 2 - $legend_size
        ) / 2);
        $index = 0;
        foreach($names as $name => $secondary){
          $color = imagecolorallocate($image,...$this->graphColors[$index++ % count($this->graphColors)]);
          $y = $height - $legend_size;
          imagefilledrectangle($image,$legend_x ,$y + 2,$legend_x + $legend_size - 4,$height - 2,$color);
          imagerectangle($image,$legend_x,$y + 2,$legend_x + $legend_size - 4,$height - 2,$color_border);
          imagestring($image,$this->graphFont,$legend_x += $legend_size,$y,$name,$color_border);
          $legend_x += strlen($name) * $font_width;
          if($secondary){
            imagestring($image,$this->graphFont,$legend_x,$y,$str = 'x' . $this->graphSecondaryFactor,$color_grid);
            $legend_x += strlen($str) * $font_width;
          }
          $legend_x += $legend_size;
          $prev_x = $prev_y = null;
          foreach($data as $time => $record) if(array_key_exists($name,$record)){
            $x = $width - round(($time_max - $time) / ($time_max - $time_min) * $graph_width);
            $y = round(($value_max - $record[$name] * ($secondary ? $this->graphSecondaryFactor : 1)) / ($value_max - $value_min) * $graph_height);
            if($prev_x !== null) imageline($image,$prev_x,$prev_y,$x,$y,$color);
            $prev_x = $x;
            $prev_y = $y;
          }
          else $prev_x = $prev_y = null;
        }
        imageline($image,$width - $graph_width,0,$width - $graph_width,$graph_height,$color_border);
        imageline($image,$width - $graph_width,$graph_height,$width,$graph_height,$color_border);
      }
    }
    return $image;
  }
 
  protected function getChecks(){
    if($this->_checks === null){
      $this->_checks = [];
      foreach($this->config('checks',[]) as $name => $config){
        $class_name = \Rsi\Record::get($config,'className',__CLASS__ . '\\Check\\' . ucfirst($name));
        $this->_checks[$name] = new $class_name($this->_fred,$config);
      }
    }
    return $this->_checks;
  }
 
}