core/tracing: add OnClose Trace Hook #29629 (#1474)

core/blockchain.go

@@ -1161,6 +1161,10 @@ func (bc *BlockChain) Stop() {
 	bc.chainmu.Close()
 	bc.wg.Wait()
 	bc.saveData()
+	// Allow tracers to clean-up and release resources.
+	if bc.logger != nil && bc.logger.OnClose != nil {
+		bc.logger.OnClose()
+	}
 	// Flush the collected preimages to disk
 	if err := bc.stateCache.TrieDB().CommitPreimages(); err != nil {
 		log.Error("Failed to commit trie preimages", "err", err)

core/tracing/hooks.go

@@ -115,6 +115,9 @@ type (
 	// BlockchainInitHook is called when the blockchain is initialized.
 	BlockchainInitHook = func(chainConfig *params.ChainConfig)
 
+	// CloseHook is called when the blockchain closes.
+	CloseHook = func()
+
 	// BlockStartHook is called before executing `block`.
 	// `td` is the total difficulty prior to `block`.
 	BlockStartHook = func(event BlockEvent)
@@ -177,6 +180,7 @@ type Hooks struct {
 	OnGasChange GasChangeHook
 	// Chain events
 	OnBlockchainInit  BlockchainInitHook
+	OnClose           CloseHook
 	OnBlockStart      BlockStartHook
 	OnBlockEnd        BlockEndHook
 	OnSkippedBlock    SkippedBlockHook