Status should not be a gauge?

[yegle]

I'm new to Prometheus so my understanding might be wrong. I don't think the status should be a gauge? Code that I'm referring to (note the conversion from t.Status to float):

transmission-exporter/cmd/transmission-exporter/torrent_collector.go

Lines 144 to 149 in df36137

	ch <- prometheus.MustNewConstMetric(
	tc.Status,
	prometheus.GaugeValue,
	float64(t.Status),
	id, t.Name,
	)

The status field in the Transmission rpc spec: https://github.com/transmission/transmission/blob/46b3e6c8dae02531b1eb8907b51611fb9229b54a/extras/rpc-spec.txt#L221

Reading transmission.h, it looks like this is an enum that corresponding to https://github.com/transmission/transmission/blob/46b3e6c8dae02531b1eb8907b51611fb9229b54a/libtransmission/transmission.h#L1814-L1824

So if my reading is correct, what needs to be changed is: The descriptor for the torrent status metric should have a status field which is the string representation of the tr_torrent_activity enum, and the value for the gauge should be 1.

		Status: prometheus.NewDesc(
			namespace+collectorNamespace+"status",
			"Status of a torrent",
			[]string{"id", "name", "status"},
			nil,

		ch <- prometheus.MustNewConstMetric(
			tc.Status,
			prometheus.GaugeValue,
			1,
			id, t.Name, enumToString(t.Status)
		)

Does it make sense? If yes I can probably send a PR to fix it.

[metalmatze]

It makes sense both ways I'd say. I don't really have a strong opinion on this very metric.
However, keep in mind that the current way it is implemented results in n time series for n statuses whereas the approach you propose results in 7*n. It might make a bigger difference for people having a lot of torrents. As the number of statuses is limited to 7, I'd still be fine with changing it to that.