chore: ignore block that too old

.gitignore

@@ -13,3 +13,4 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+.env

pkg/listener/handler.go

@@ -2,6 +2,7 @@ package listener
 
 import (
 	"context"
+	"math/big"
 
 	"github.com/KyberNetwork/evmlistener/pkg/block"
 	"github.com/KyberNetwork/evmlistener/pkg/errors"
@@ -208,6 +209,18 @@ func (h *Handler) handleNewBlock(ctx context.Context, b types.Block) error {
 
 	log.Infow("Handling new block")
 
+	blockHead, err := h.blockKeeper.Head()
+	if err == nil {
+		blockDiff := new(big.Int).Sub(blockHead.Number, b.Number).Int64()
+		if blockDiff > int64(h.blockKeeper.Cap()) {
+			log.Warnw("Ignore block that too old",
+				"blockNumber", b.Number,
+				"blockHeadNumber", blockHead.Number,
+				"blockDiff", blockDiff)
+			return nil
+		}
+	}
+
 	isReorg, err := h.blockKeeper.IsReorg(b)
 	if err != nil {
 		log.Errorw("Fail to check for re-organization", "error", err)