Extended metrics and the /__stats endpoint

Document updated on May 2, 2021

The metrics middleware collects extended metrics and exposes them in the /__stats/ endpoint. The endpoint runs in a different port than the API, and contains a lot of metrics.

Through the extended metrics you can create new tools or integrate with existing ones. For instance, combining the metrics with the InfluxDB extended metrics you can have a Grafana dashboard.

Configuration

In order to add metrics to your KrakenD installation add the github_com/devopsfaith/krakend-metrics namespace under extra_config in the root of your configuration file, e.g.:

{
  "version": 2,
  "extra_config": {
    "github_com/devopsfaith/krakend-metrics": {
      "collection_time": "60s",
      "proxy_disabled": false,
      "router_disabled": false,
      "backend_disabled": false,
      "endpoint_disabled": false,
      "listen_address": ":8090"
    }
  }
}

The options of the middleware are:

• collection_time: The time window to collect metrics. Defaults to 60 seconds.
• proxy_disabled: Skip any metrics happening in the proxy layer (traffic against your backends)
• router_disabled: Skip any metrics happening in the router layer (activity in KrakenD endpoints)
• backend_disabled: Skip any metrics happening in the backend layer.
• endpoint_disabled: Do not publish the /__stats/ endpoint. Metrics won’t be accessible via the endpoint but still collected.
• listen_address: Change the listening address where the metrics endpoint is exposed. It defaults to :8090.

The structure of the metrics looks like this (truncated):

$curl http://localhost:8090/__stats
{
  "cmdline": [
    "/usr/bin/krakend",
    "run",
    "-c",
    "/etc/krakend/krakend.json",
    "-d"
  ],
  "krakend.router.connected": 0,
  "krakend.router.connected-gauge": 0,
  "krakend.router.connected-total": 0,
  "krakend.router.disconnected": 0,
  "krakend.router.disconnected-gauge": 0,
  "krakend.router.disconnected-total": 0,
  "krakend.service.debug.GCStats.LastGC": 1605724147216402400,
  "krakend.service.debug.GCStats.NumGC": 102,
  "krakend.service.debug.GCStats.Pause.50-percentile": 0,
  "krakend.service.debug.GCStats.Pause.75-percentile": 0,
  "krakend.service.debug.GCStats.Pause.95-percentile": 0,
  "krakend.service.debug.GCStats.Pause.99-percentile": 0,
  "krakend.service.debug.GCStats.Pause.999-percentile": 0,
  "krakend.service.debug.GCStats.Pause.count": 0,
  "krakend.service.debug.GCStats.Pause.max": 0,
  "krakend.service.debug.GCStats.Pause.mean": 0,
  "krakend.service.debug.GCStats.Pause.min": 0,
  "krakend.service.debug.GCStats.Pause.std-dev": 0,
    ...
  }
}