How to log the full errorinfo from phpmailer?

I use phpmailer to send mails and I would like to log the error from phpmailer when it occurs. I can only get a part of the error and not the whole error.

For logging I'm using monolog.

$log = new Logger('contact.php');
$log->pushHandler(new StreamHandler('./error.log',logger::WARNING));

As @Synchro suggested I've tried to use closure to capture the whole debug.

  if (!$err) {
      $mail = new PHPMailer(true);
      $mail->isSMTP();
      $mail->Host = 'maildev';
      $mail->SMTPDebug = 3;                                       // Enable verbose debug output
      $mail->SMTPAuth   = false;                                   // Enable SMTP authentication
      $mail->Debugoutput = 'html';
      $mail->SMTPAutoTLS = false; 
      $mail->Port       = '259';
      $mail->CharSet = 'utf-8';
      //$mail->setFrom($config['mail']['sendTo'], (empty($name) ? 'Contact form' : $name));
      $mail->setFrom($config['mail']['sendTo']);
      $mail->addAddress($config['mail']['sendTo']);
      $mail->addReplyTo($email, $name);
      $mail->isHtml();
      $mail->Subject = 'Contact form: ' . $subject;
      $mail->Body =  $query;
      $result="Thank you for connecting with us! We'll reply as soon as possible to you.";
      $form->clearPost();

    try {
      $debuglog = '';
      $mail->Debugoutput = function($str, $level) use ($debuglog) {
          $debuglog .= $str;
      };
      if (!$mail->send()) {
          $msg .= "Mailer Error: " . $mail->ErrorInfo;
          array_push($extra_info,['name',$name,$email,$query]);
          $log->error($debuglog, $extra_info);
      } else {
          $msg .= "Message sent!";
          $result="Thank you for connecting with us! We'll reply as soon as possible to you.";
      }
    } catch (phpmailerException $exp) {
      $debugError = $exp->errorMessage();
    }
  $log->error($debugError);

$debugError and $debuginfo are both NULL.

Errorinfo produces the next output in the browser:

2019-08-20 14:10:53 Connection: opening to maildev:259, timeout=300, options=array()
2019-08-20 14:10:53 Connection failed. Error #2: stream_socket_client(): unable to connect to maildev:259 (Connection refused) [/srv/http/vendor/phpmailer/phpmailer/src/SMTP.php line 326]
2019-08-20 14:10:53 SMTP ERROR: Failed to connect to server: Connection refused (111)
SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

But in the log file I get only:

[2019-08-20 14:10:53] contact.php.ERROR: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting ["172.27.0.1",["name","t","[email protected]","werty"]] []

How can I log the full debugging message instead of only SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting?

Solution

PHPMailer produces debug output that is separate from the final error message that's in ErrorInfo - for example debug output is present even when there are no errors.

If you want to capture all the debug output, you can inject a closure, which is documented in the source like this:

$mail->Debugoutput = function($str, $level) use ($log) {
    $log->error("debug level $level; message: $str");
};

You don't say what is in $log, but if it's a PSR-3 logger, you can simply do this:

$mail->Debugoutput = $log;

Note that this will always produce output - if you want a subset of it it's up to you to filter it before sending it to your log.