flake.lock: Update

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/2795c506fe8fb7b03c36ccb51f75b6df0ab2553f?narHash=sha256-W7lqHp0qZiENCDwUZ5EX/lNhxjMdNapFnbErcbnP11Q%3D' (2025-05-20)
  → 'github:NixOS/nixpkgs/910796cabe436259a29a72e8d3f5e180fc6dfacc?narHash=sha256-StSrWhklmDuXT93yc3GrTlb0cKSS0agTAxMGjLKAsY8%3D' (2025-05-31)

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1747744144,
+        "lastModified": 1748693115,
-        "narHash": "sha256-W7lqHp0qZiENCDwUZ5EX/lNhxjMdNapFnbErcbnP11Q=",
+        "narHash": "sha256-StSrWhklmDuXT93yc3GrTlb0cKSS0agTAxMGjLKAsY8=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "2795c506fe8fb7b03c36ccb51f75b6df0ab2553f",
+        "rev": "910796cabe436259a29a72e8d3f5e180fc6dfacc",
         "type": "github"
       },
       "original": {

main.go

@@ -17,7 +17,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
-const Version = "0.1.0"
+const Version = "0.1.1"
 
 func LoadConfig() (*config.Config, error) {
 	path := "labmon.toml"

stepmon/stepmon.go

@@ -29,6 +29,13 @@ var stepCertError = promauto.NewGaugeVec(prometheus.GaugeOpts{
 	Help:      "Error checking the certificate.",
 }, []string{"cert_id"})
 
+var stepCertLifetime = promauto.NewGaugeVec(prometheus.GaugeOpts{
+	Namespace: "labmon",
+	Subsystem: "stepmon",
+	Name:      "certificate_lifetime_seconds",
+	Help:      "How long the certificate is valid in seconds.",
+}, []string{"cert_id"})
+
 type StepMonitor struct {
 	BaseURL string
 	RootID  string
@@ -77,6 +84,8 @@ func (sm *StepMonitor) Start() {
 				stepCertError.WithLabelValues(sm.RootID).Set(1)
 			} else {
 				stepCertError.WithLabelValues(sm.RootID).Set(0)
+				lifetime := sm.certificate.NotAfter.Sub(sm.certificate.NotBefore).Seconds()
+				stepCertLifetime.WithLabelValues(sm.RootID).Set(lifetime)
 			}
 
 			timerCertFetch.Reset(5 * time.Minute)

tlsconmon/tlsconmon.go

@@ -37,6 +37,13 @@ var (
 		Help:      "Error checking the certificate.",
 	}, []string{"address"})
 
+	gaugeCertLifetime = promauto.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: "labmon",
+		Subsystem: "tlsconmon",
+		Name:      "certificate_lifetime_seconds",
+		Help:      "How long the certificate is valid in seconds.",
+	}, []string{"address"})
+
 	// OTEL tracing
 	tracer = otel.Tracer(name)
 )
@@ -104,6 +111,8 @@ func (tm *TLSConnectionMonitor) Start(ctx context.Context) {
 	if err := tm.fetchCert(ctx); err != nil {
 		gaugeCertError.WithLabelValues(tm.Address).Set(1)
 		gaugeCertTimeLeft.WithLabelValues(tm.Address).Set(0)
+		lifetime := tm.cert.NotAfter.Sub(tm.cert.NotBefore).Seconds()
+		gaugeCertLifetime.WithLabelValues(tm.Address).Set(lifetime)
 	} else {
 		gaugeCertError.WithLabelValues(tm.Address).Set(0)
 		timeLeft := time.Until(tm.cert.NotAfter).Seconds()