syslog.module

<?php
/**
 * @file
 * Redirects logging messages to syslog.
 */

if (defined('LOG_LOCAL0')) {
  /**
   * Sets the proper logging facility.
   *
   * Note that LOG_LOCAL0 through LOG_LOCAL7 are not available on Windows, so we
   * check for availability. If LOG_LOCAL0 is defined by the PHP environment, we
   * set that as the default; if not, we use LOG_USER.
   *
   * @see http://php.net/manual/function.syslog.php
   */
  define('DEFAULT_SYSLOG_FACILITY', LOG_LOCAL0);
}
else {
  define('DEFAULT_SYSLOG_FACILITY', LOG_USER);
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function syslog_form_system_logging_settings_alter(&$form, &$form_state) {
  $config = config('system.core');
  $help = module_exists('help') ? ' ' . l(t('More information'), 'admin/help/syslog') . '.' : NULL;
  $form['syslog_identity'] = array(
    '#type'          => 'textfield',
    '#title'         => t('Syslog identity'),
    '#default_value' => $config->get('log_identity'),
    '#description'   => t('A string that will be prepended to every message logged to Syslog. If you have multiple sites logging to the same Syslog log file, a unique identity per site makes it easy to tell the log entries apart.') . $help,
  );
  if (defined('LOG_LOCAL0')) {
    $form['syslog_facility'] = array(
      '#type'          => 'select',
      '#title'         => t('Syslog facility'),
      '#default_value' => $config->get('log_facility'),
      '#options'       => syslog_facility_list(),
      '#description'   => t('Depending on the system configuration, Syslog and other logging tools use this code to identify or filter messages from within the entire system log.') . $help,
     );
  }
  $form['syslog_format'] = array(
    '#type'          => 'textarea',
    '#title'         => t('Syslog format'),
    '#default_value' => $config->get('log_format'),
    '#description'   => t('Specify the format of the syslog entry. Available variables are: <dl><dt><code>!base_url</code></dt><dd>Base URL of the site.</dd><dt><code>!timestamp</code></dt><dd>Unix timestamp of the log entry.</dd><dt><code>!type</code></dt><dd>The category to which this message belongs.</dd><dt><code>!ip</code></dt><dd>IP address of the user triggering the message.</dd><dt><code>!request_uri</code></dt><dd>The requested URI.</dd><dt><code>!referer</code></dt><dd>HTTP Referer if available.</dd><dt><code>!uid</code></dt><dd>User ID.</dd><dt><code>!link</code></dt><dd>A link to associate with the message.</dd><dt><code>!message</code></dt><dd>The message to store in the log.</dd></dl>'),
  );
  $form['#submit'][] = 'syslog_logging_settings_submit';
}

/**
 * Form submission handler for system_logging_settings().
 *
 * @see syslog_form_system_logging_settings_alter()
 */
function syslog_logging_settings_submit($form, &$form_state) {
  config('system.core')
    ->set('log_identity', $form_state['values']['syslog_identity'])
    ->set('log_facility', $form_state['values']['syslog_facility'])
    ->set('log_format', $form_state['values']['syslog_format'])
    ->save();
}

/**
 * List all possible syslog facilities for UNIX/Linux.
 *
 * @return array
 *  An array of syslog facilities for UNIX/Linux.
 */
function syslog_facility_list() {
  return array(
    LOG_LOCAL0 => 'LOG_LOCAL0',
    LOG_LOCAL1 => 'LOG_LOCAL1',
    LOG_LOCAL2 => 'LOG_LOCAL2',
    LOG_LOCAL3 => 'LOG_LOCAL3',
    LOG_LOCAL4 => 'LOG_LOCAL4',
    LOG_LOCAL5 => 'LOG_LOCAL5',
    LOG_LOCAL6 => 'LOG_LOCAL6',
    LOG_LOCAL7 => 'LOG_LOCAL7',
  );
}

/**
 * Implements hook_watchdog().
 */
function syslog_watchdog(array $log_entry) {
  global $base_url;

  $log_init = &backdrop_static(__FUNCTION__, FALSE);
  $config = config('system.core');

  if (!$log_init) {
    $log_init = TRUE;
    $facility = $config->get('log_facility');
    if ($facility === '') {
      $facility = defined('LOG_LOCAL0') ? LOG_LOCAL0 : LOG_USER;
    }
    openlog($config->get('log_identity'), LOG_NDELAY, $facility);
  }

  $message = strtr($config->get('log_format'), array(
    '!base_url'    => $base_url,
    '!timestamp'   => $log_entry['timestamp'],
    '!type'        => $log_entry['type'],
    '!ip'          => $log_entry['ip'],
    '!request_uri' => $log_entry['request_uri'],
    '!referer'     => $log_entry['referer'],
    '!uid'         => $log_entry['uid'],
    '!link'        => strip_tags((string) $log_entry['link']),
    '!message'     => strip_tags((string) (!isset($log_entry['variables']) ? $log_entry['message'] : strtr($log_entry['message'], $log_entry['variables']))),
  ));

  syslog($log_entry['severity'], $message);
}