Exporting events to Loki

Grafana Loki is an open source log aggregation system inspired by Prometheus. While it is possible to use Loki with Grafana Alloy, a simpler approach is to send logs directly using the Loki HTTP API.

The following example modifies the ddos-protect application to use sFlow-RT's httpAsync() function to send events to Loki's HTTP API.

var lokiPort = getSystemProperty("ddos_protect.loki.port") || '3100';
var lokiPush = getSystemProperty("ddos_protect.loki.push") || '/loki/api/v1/push';
var lokiHost = getSystemProperty("ddos_protect.loki.host");

function sendEvent(action,attack,target,group,protocol) {
  if(lokiHost) {
    var url = 'http://'+lokiHost+':'+lokiPort+lokiPush;
    lokiEvent = {
      streams: [
        {
          stream: {
            service_name: 'ddos-protect'
          },
          values: [[
            Date.now()+'000000',
            action+" "+attack+" "+target+" "+group+" "+protocol,
            {
              detected_level: action == 'release' ? 'INFO' : 'WARN',
              action: action,
              attack: attack,
              ip: target,
              group: group,
              protocol: protocol
            }
          ]]
        }
      ]
    };
    httpAsync({
      url: url,
      headers: {'Content-Type':'application/json'},
      operation: 'POST',
      body: JSON.stringify(lokiEvent),
      success: (response) => { 
        if (200 != response.status) {
          logWarning("DDoS Loki status " + response.status);
        }
      },
      error: (error) => {
        logWarning("DDoS Loki error " + error);
      }
    });
  }

  if(syslogHosts.length === 0) return;

  var msg = {app:'ddos-protect',action:action,attack:attack,ip:target,group:group,protocol:protocol};
  syslogHosts.forEach(function(host) {
    try {
      syslog(host,syslogPort,syslogFacility,syslogSeverity,msg);
    } catch(e) {
      logWarning('DDoS cannot send syslog to ' + host);
    }
  });
}

The highlighted code extends the existing scripts/ddos.js script to add Loki support.

Add a panel to integrate the Loki log into the Grafana sFlow-RT DDoS Protect dashboard as shown at the top of this page.

DDoS protection quickstart guide describes how to set up a DDoS mitigation solution using sFlow-RT.