fixed duplicate register issue

cmd/solana_exporter/exporter.go

@@ -209,15 +209,15 @@ func main() {
 	}
 
 	client := rpc.NewRPCClient(config.RpcUrl, config.HttpTimeout)
-	ctx_, cancel := context.WithTimeout(ctx, config.HttpTimeout)
+	votekeys, err := GetAssociatedVoteAccounts(ctx, client, rpc.CommitmentFinalized, config.NodeKeys)
-	defer cancel()
-	votekeys, err := GetAssociatedVoteAccounts(ctx_, client, rpc.CommitmentFinalized, config.NodeKeys)
 	if err != nil {
 		klog.Fatalf("Failed to get associated vote accounts for %v: %v", config.NodeKeys, err)
 	}
 
 	collector := NewSolanaCollector(client, slotPacerSchedule, config.BalanceAddresses, config.NodeKeys, votekeys)
 	slotWatcher := NewSlotWatcher(client, config.NodeKeys, votekeys, config.ComprehensiveSlotTracking)
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
 	go slotWatcher.WatchSlots(ctx, collector.slotPace)
 
 	prometheus.MustRegister(collector)

cmd/solana_exporter/slots.go

@@ -107,15 +107,29 @@ func NewSlotWatcher(
 		),
 	}
 	// register:
-	prometheus.MustRegister(watcher.TotalTransactionsMetric)
+	for _, collector := range []prometheus.Collector{
-	prometheus.MustRegister(watcher.SlotHeightMetric)
+		watcher.TotalTransactionsMetric,
-	prometheus.MustRegister(watcher.EpochNumberMetric)
+		watcher.SlotHeightMetric,
-	prometheus.MustRegister(watcher.EpochFirstSlotMetric)
+		watcher.EpochNumberMetric,
-	prometheus.MustRegister(watcher.EpochLastSlotMetric)
+		watcher.EpochFirstSlotMetric,
-	prometheus.MustRegister(watcher.LeaderSlotsTotalMetric)
+		watcher.EpochLastSlotMetric,
-	prometheus.MustRegister(watcher.LeaderSlotsByEpochMetric)
+		watcher.LeaderSlotsTotalMetric,
-	prometheus.MustRegister(watcher.InflationRewardsMetric)
+		watcher.LeaderSlotsByEpochMetric,
-	prometheus.MustRegister(watcher.FeeRewardsMetric)
+		watcher.InflationRewardsMetric,
+		watcher.FeeRewardsMetric,
+	} {
+		if err := prometheus.Register(collector); err != nil {
+			var (
+				alreadyRegisteredErr *prometheus.AlreadyRegisteredError
+				duplicateErr         = strings.Contains(err.Error(), "duplicate metrics collector registration attempted")
+			)
+			if errors.As(err, &alreadyRegisteredErr) || duplicateErr {
+				continue
+			} else {
+				klog.Fatal(fmt.Errorf("failed to register collector: %w", err))
+			}
+		}
+	}
 	return &watcher
 }