## `prometheus` sink

The `prometheus` sink publishes all metrics via an HTTP server ready to be scraped by a [Prometheus](https://prometheus.io) server. It creates gauge metrics for all node metrics and gauge vectors for all metrics with a subtype like 'device', 'cpu' or 'socket'. 


### Configuration structure

```json
{
  "<name>": {
    "type": "prometheus",
    "host": "localhost",
    "port": "8080",
    "path": "metrics"
  }
}
```

- `type`: makes the sink an `prometheus` sink
- `host`: The HTTP server gets bound to that IP/hostname
- `port`: Portnumber (as string) for the HTTP server
- `path`: Path where the metrics should be servered. The metrics will be published at `host`:`port`/`path`
- `group_as_namespace`: Most metrics contain a group as meta information like 'memory', 'load'. With this the metric names are extended to `group`_`name` if possible.