feat: exported metrics for current finalized and safe block number (h…

…yperledger#7592)

* feat: exported metrics for current finalized and safe block number

Signed-off-by: Jones Ho <jones.ho@consensys.net>

* Update ethereum/core/src/main/java/org/hyperledger/besu/ethereum/chain/DefaultBlockchain.java

Co-authored-by: Fabio Di Fabio <fabio.difabio@consensys.net>
Signed-off-by: jonesho <81145364+jonesho@users.noreply.github.com>

* Update ethereum/core/src/main/java/org/hyperledger/besu/ethereum/chain/DefaultBlockchain.java

Co-authored-by: Fabio Di Fabio <fabio.difabio@consensys.net>
Signed-off-by: jonesho <81145364+jonesho@users.noreply.github.com>

* fix: spotless issue

Signed-off-by: Jones Ho <jones.ho@consensys.net>

---------

Signed-off-by: Jones Ho <jones.ho@consensys.net>
Signed-off-by: jonesho <81145364+jonesho@users.noreply.github.com>
Co-authored-by: Fabio Di Fabio <fabio.difabio@consensys.net>

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/chain/DefaultBlockchain.java

@@ -122,6 +122,18 @@ private DefaultBlockchain(
  "The current height of the canonical chain",
  this::getChainHeadBlockNumber);
 
+ metricsSystem.createLongGauge(
+ BesuMetricCategory.ETHEREUM,
+ "blockchain_finalized_block",
+ "The current finalized block number",
+ this::getFinalizedBlockNumber);
+
+ metricsSystem.createLongGauge(
+ BesuMetricCategory.ETHEREUM,
+ "blockchain_safe_block",
+ "The current safe block number",
+ this::getSafeBlockNumber);
+
  metricsSystem.createGauge(
  BesuMetricCategory.BLOCKCHAIN,
  "difficulty_total",
@@ -759,6 +771,14 @@ public void setSafeBlock(final Hash blockHash) {
  updater.commit();
  }
 
+ private long getFinalizedBlockNumber() {
+ return this.getFinalized().flatMap(this::getBlockHeader).map(BlockHeader::getNumber).orElse(0L);
+ }
+
+ private long getSafeBlockNumber() {
+ return this.getSafeBlock().flatMap(this::getBlockHeader).map(BlockHeader::getNumber).orElse(0L);
+ }
+
  private void updateCacheForNewCanonicalHead(final Block block, final Difficulty uInt256) {
  chainHeader = block.getHeader();
  totalDifficulty = uInt256;