librenms-librenms/includes/polling/functions.inc.php

<?php

function poll_sensor($device, $class, $unit)
{
  global $config;

  foreach (dbFetchRows("SELECT * FROM `sensors` WHERE `sensor_class` = ? AND `device_id` = ? AND `poller_type` = 'snmp'", array($class, $device['device_id'])) as $sensor)
  {
    echo("Checking $class " . $sensor['sensor_descr'] . "... ");

    if($class == "temperature")
    {  
      for ($i = 0;$i < 5;$i++) # Try 5 times to get a valid temp reading
      {
        if ($debug) echo("Attempt $i ");
        $sensor_value = snmp_get($device, $sensor['sensor_oid'], "-OUqnv", "SNMPv2-MIB");
        $sensor_value = trim(str_replace("\"", "", $sensor_value));

        if ($sensor_value != 9999) break; # TME sometimes sends 999.9 when it is right in the middle of an update;
        sleep(1); # Give the TME some time to reset
      }
    } else {
      $sensor_value = snmp_get($device, $sensor['sensor_oid'], "-OUqnv", "SNMPv2-MIB");
    }

    if ($sensor['sensor_divisor'])    { $sensor_value = $sensor_value / $sensor['sensor_divisor']; }
    if ($sensor['sensor_multiplier']) { $sensor_value = $sensor_value * $sensor['sensor_multiplier']; }

    $rrd_file = get_sensor_rrd($device, $sensor);

    #$rrd_file = $config['rrd_dir']."/".$device['hostname']."/".safename("sensor-".$sensor['sensor_class']."-".$sensor['sensor_type']."-".$sensor['sensor_index'] . ".rrd");

    ## FIXME - sensor name format change 2011/04/26 - remove this in $amount_of_time. 
    ## We don't want to reduce performance forever because douchebags don't svn up!
    $old_rrd_file = $config['rrd_dir'] . "/" . $device['hostname'] . "/" . safename("$class-" . $sensor['sensor_descr'] . ".rrd");
    $old_rrd_file_b = $config['rrd_dir'] . "/" . $device['hostname'] . "/" . safename("$class-" . $sensor['sensor_index'] . ".rrd");
    if (is_file($old_rrd_file) && is_file($old_rrd_file_b)) 
    { 
      rename($old_rrd_file, $rrd_file); 
      unlink($old_rrd_file_b);
    } elseif (is_file($old_rrd_file)) {
      rename($old_rrd_file, $rrd_file);
    } elseif (is_file($old_rrd_file_b)) {
      rename($old_rrd_file_b, $rrd_file);
    }

    if (!is_file($rrd_file))
    {
      rrdtool_create($rrd_file,"--step 300 \
      DS:sensor:GAUGE:600:-20000:20000 \
      RRA:AVERAGE:0.5:1:1200 \
      RRA:AVERAGE:0.5:12:2400 \
      RRA:AVERAGE:0.5:288:1200 \
      RRA:MAX:0.5:12:2400 \
      RRA:MAX:0.5:288:1200 \
      RRA:MIN:0.5:12:2400 \
      RRA:MIN:0.5:288:1200");
    }

    echo("$sensor_value $unit\n");

    rrdtool_update($rrd_file,"N:$sensor_value");

    # FIXME also warn when crossing WARN level!!
    if ($sensor['sensor_limit_low'] != "" && $sensor['sensor_current'] > $sensor['sensor_limit_low'] && $sensor_value <= $sensor['sensor_limit_low'])
    {
      $msg  = ucfirst($class) . " Alarm: " . $device['hostname'] . " " . $sensor['sensor_descr'] . " is under threshold: " . $sensor_value . "$unit (< " . $sensor['sensor_limit'];
      $msg .= "$unit) at " . date($config['timestamp_format']);
      notify($device, ucfirst($class) . " Alarm: " . $device['hostname'] . " " . $sensor['sensor_descr'], $msg);
      echo("Alerting for " . $device['hostname'] . " " . $sensor['sensor_descr'] . "\n");
      log_event(ucfirst($class) . ' ' . $sensor['sensor_descr'] . " under threshold: " . $sensor_value . " $unit (< " . $sensor['sensor_limit_low'] . " $unit)", $device, $class, $sensor['sensor_id']);
    }
    else if ($sensor['sensor_limit'] != "" && $sensor['sensor_current'] < $sensor['sensor_limit'] && $sensor_value >= $sensor['sensor_limit'])
    {
      $msg  = ucfirst($class) . " Alarm: " . $device['hostname'] . " " . $sensor['sensor_descr'] . " is over threshold: " . $sensor_value . "$unit (> " . $sensor['sensor_limit'];
      $msg .= "$unit) at " . date($config['timestamp_format']);
      notify($device, ucfirst($class) . " Alarm: " . $device['hostname'] . " " . $sensor['sensor_descr'], $msg);
      echo("Alerting for " . $device['hostname'] . " " . $sensor['sensor_descr'] . "\n");
      log_event(ucfirst($class) . ' ' . $sensor['sensor_descr'] . " above threshold: " . $sensor_value . " $unit (> " . $sensor['sensor_limit'] . " $unit)", $device, $class, $sensor['sensor_id']);
    }

    dbUpdate(array('sensor_current' => $sensor_value), 'sensors', '`sensor_class` = ? AND `sensor_id` = ?', array($class, $sensor['sensor_id']));
  }
}

?>