Update the metric names to match Prometheus conventions

I found a few improvements to the metrics based on https://prometheus.io/docs/practices/naming/

These are good recommendations in general, and having standard units makes it easier
to use the metrics in queries.

For example, having everything in bytes, means you can just divide one metric by another
without conversion.

Having the timestamp in seconds allows easy use with the `time()` function.

Signed-off-by: Goutham <[email protected]>

Author: gouthamve

README.md

@@ -46,15 +46,15 @@ It exposes the following metrics:
 | Metric | Description |
 |-|-|
 | `unused_disks_count` | How many unused disks are in this provider |
-| `unused_disks_size_gb` | Total size of unused disks in this provider in GB |
+| `unused_disks_total_size_bytes` | Total size of unused disks in this provider in bytes |
 | `unused_disk_size_bytes` | Size of each disk in bytes |
-| `unused_disks_last_used_at` | Last timestamp (unix ms) when this disk was used. GCP only! |
-| `unused_provider_duration_ms` | How long in milliseconds took to fetch this provider information |
+| `unused_disks_last_used_timestamp_seconds` | Last timestamp (unix seconds) when this disk was used. GCP only! |
+| `unused_provider_duration_seconds` | How long in milliseconds took to fetch this provider information |
 | `unused_provider_info` | CSP information |
 | `unused_provider_success` | Static metric indicating if collecting the metrics succeeded or not |
 
 All metrics have the `provider` and `provider_id` labels to identify to which provider instance they belong.
-The `unused_disks_count` and `unused_disks_size_gb` metrics have an additional `k8s_namespace` metric mapped to the `kubernetes.io/created-for/pvc/namespace` annotation assigned to persistent disks created by Kubernetes.
+The `unused_disks_count` and `unused_disks_total_size_bytes` metrics have an additional `k8s_namespace` metric mapped to the `kubernetes.io/created-for/pvc/namespace` annotation assigned to persistent disks created by Kubernetes.
 
 Information about each unused disk is currently logged to stdout given that it contains more changing information that could lead to cardinality explosion.
 

cmd/unused-exporter/exporter.go

@@ -74,14 +74,14 @@ func registerExporter(ctx context.Context, providers []unused.Provider, cfg conf
 			nil),
 
 		size: prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "disks", "size_gb"),
-			"Total size of unused disks in this provider in GB",
+			prometheus.BuildFQName(namespace, "disks", "total_size_bytes"),
+			"Total size of unused disks in this provider in bytes",
 			append(labels, "k8s_namespace", "type"),
 			nil),
 
 		dur: prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "provider", "duration_ms"),
-			"How long in milliseconds took to fetch this provider information",
+			prometheus.BuildFQName(namespace, "provider", "duration_seconds"),
+			"How long in seconds took to fetch this provider information",
 			labels,
 			nil),
 
@@ -92,7 +92,7 @@ func registerExporter(ctx context.Context, providers []unused.Provider, cfg conf
 			nil),
 
 		dlu: prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "disks", "last_used_at"),
+			prometheus.BuildFQName(namespace, "disks", "last_used_timestamp_seconds"),
 			"Kubernetes metadata associated with each unused disk, with the value as the last time the disk was used (if available)",
 			append(labels, []string{"disk", "created_for_pv", "created_for_pvc", "zone"}...),
 			nil),
@@ -176,7 +176,7 @@ func (e *exporter) pollProvider(p unused.Provider) {
 					diskInfoByNamespace[ns] = di
 				}
 				di.Count += 1
-				di.SizeByType[d.DiskType()] += float64(d.SizeGB())
+				di.SizeByType[d.DiskType()] += float64(d.SizeBytes())
 
 				e.logger.Info(fmt.Sprintf("Disk %s last used at %v", d.Name(), d.LastUsedAt()))
 
@@ -190,7 +190,7 @@ func (e *exporter) pollProvider(p unused.Provider) {
 			}
 
 			addMetric(&ms, p, e.info, 1)
-			addMetric(&ms, p, e.dur, float64(dur.Milliseconds()))
+			addMetric(&ms, p, e.dur, float64(dur.Seconds()))
 			addMetric(&ms, p, e.suc, float64(success))
 
 			for ns, di := range diskInfoByNamespace {
@@ -290,7 +290,7 @@ func lastUsedTS(d unused.Disk) float64 {
 		return 0
 	}
 
-	return float64(lastUsed.UnixMilli())
+	return float64(lastUsed.Unix())
 }
 
 func getRegionFromZone(p unused.Provider, z string) string {