Report info metric as 0 the first time to track when software is (re)started

metrics/metrics_info.go

@@ -3,10 +3,13 @@ package metrics
 import (
 	"runtime"
 	"strings"
+	"sync/atomic"
 
 	"github.com/safing/portbase/info"
 )
 
+var reportedStart atomic.Bool
+
 func registerInfoMetric() error {
 	meta := info.GetInfo()
 	_, err := NewGauge(
@@ -26,6 +29,10 @@ func registerInfoMetric() error {
 			"comment":       commentOption(),
 		},
 		func() float64 {
+			// Report as 0 the first time in order to detect (re)starts.
+			if reportedStart.CompareAndSwap(false, true) {
+				return 0
+			}
 			return 1
 		},
 		nil,