sync: coreth PR #1423: add min delay metrics (#1890)

Co-authored-by: Ceyhun Onur <ceyhun.onur@avalabs.org>

Author: JonathanOppenheimer

core/blockchain.go

@@ -123,6 +123,9 @@ var (
 	acceptedLogsCounter  = metrics.GetOrRegisterCounter("chain/logs/accepted", nil)
 	processedLogsCounter = metrics.GetOrRegisterCounter("chain/logs/processed", nil)
 
+	latestMinDelayGauge       = metrics.NewRegisteredGauge("chain/latest/mindelay", nil)
+	latestMinDelayExcessGauge = metrics.NewRegisteredGauge("chain/latest/mindelay/excess", nil)
+
 	ErrRefuseToCorruptArchiver = errors.New("node has operated with pruning disabled, shutting down to prevent missing tries")
 
 	errFutureBlockUnsupported  = errors.New("future block insertion not supported")
@@ -1139,6 +1142,14 @@ func (bc *BlockChain) Accept(block *types.Block) error {
 	} else {
 		blockTotalFeesGauge.Update(total.Int64())
 	}
+	if params.GetExtra(bc.chainConfig).IsGranite(block.Time()) {
+		extraHeader := customtypes.GetHeaderExtra(block.Header())
+		if extraHeader.MinDelayExcess != nil {
+			delayExcess := *extraHeader.MinDelayExcess
+			latestMinDelayGauge.Update(int64(delayExcess.Delay()))
+			latestMinDelayExcessGauge.Update(int64(delayExcess))
+		}
+	}
 	return nil
 }