The `interval` defines how often the metrics should be read and send to the sink. The `duration` tells collectors how long one measurement has to take. An example for this is the `likwid` collector which starts the hardware performance counter, waits for `duration` seconds and stops the counters again. For most systems, the `likwid` collector has to do two measurements, thus `interval` must be larger than two times `duration`.
All available collectors are listed in the above JSON. A more detailed list can be found in the [README for collectors](./collectors/README.md).
There are currently three sinks supported `influxdb`, `nats` and `stdout`. See [README for sinks](./sinks/README.md).
In the `default_tags` section, one can define key-value-pairs (only strings) that are added to each sent out metric. This can be useful for cluster names like in the example JSON or information like rank or island for orientation.
With `receiver`, the collector can be used as a router by receiving metrics and forwarding them to the configured sink. There are currently only types `none` (for no receiver) and `nats`. For more information see the [README in receivers](./receivers/README.md).
The metric collector sends (and receives) metric in the [InfluxDB line protocol](https://docs.influxdata.com/influxdb/cloud/reference/syntax/line-protocol/) as it provides flexibility while providing a separation between tags (like index columns in relational databases) and fields (like data columns).
There is a single timer loop that triggers all collectors serially, collects the collectors' data and sends the metrics to the sink. This is done as all data is submitted with a single time stamp. The sinks currently use mostly blocking APIs.
