[Plugin API] - TransactionSelector - Notify plugins when transaction is selected/rejected (#6005)

Signed-off-by: Gabriel-Trintinalia <gabriel.trintinalia@consensys.net>

ethereum/blockcreation/src/main/java/org/hyperledger/besu/ethereum/blockcreation/txselection/BlockTransactionSelector.java

@@ -145,8 +145,7 @@ public class BlockTransactionSelector {
             pendingTransaction -> {
               final var res = evaluateTransaction(pendingTransaction);
               if (!res.selected()) {
-                transactionSelectionResults.updateNotSelected(
-                    pendingTransaction.getTransaction(), res);
+                updateTransactionRejected(pendingTransaction, res);
               }
               return res;
             });
@@ -169,9 +168,10 @@ public class BlockTransactionSelector {
   public TransactionSelectionResults evaluateTransactions(final List<Transaction> transactions) {
     transactions.forEach(
         transaction -> {
-          final var res = evaluateTransaction(new PendingTransaction.Local(transaction));
+          var pendingTransaction = new PendingTransaction.Local(transaction);
+          final var res = evaluateTransaction(pendingTransaction);
           if (!res.selected()) {
-            transactionSelectionResults.updateNotSelected(transaction, res);
+            updateTransactionRejected(pendingTransaction, res);
           }
         });
     return transactionSelectionResults;
@@ -234,8 +234,7 @@ public class BlockTransactionSelector {
     final long blobGasUsed =
         blockSelectionContext.gasCalculator().blobGasCost(transaction.getBlobCount());
 
-    transactionSelectionResults.updateSelected(
-        transaction, receipt, gasUsedByTransaction, blobGasUsed);
+    updateTransactionSelected(pendingTransaction, receipt, gasUsedByTransaction, blobGasUsed);
 
     LOG.atTrace()
         .setMessage("Selected {} for block creation")
@@ -245,6 +244,30 @@ public class BlockTransactionSelector {
     return TransactionSelectionResult.SELECTED;
   }
 
+  private void updateTransactionSelected(
+      final PendingTransaction pendingTransaction,
+      final TransactionReceipt receipt,
+      final long gasUsedByTransaction,
+      final long blobGasUsed) {
+
+    transactionSelectionResults.updateSelected(
+        pendingTransaction.getTransaction(), receipt, gasUsedByTransaction, blobGasUsed);
+
+    // notify external selector if any
+    externalTransactionSelector.onTransactionSelected(pendingTransaction);
+  }
+
+  private void updateTransactionRejected(
+      final PendingTransaction pendingTransaction,
+      final TransactionSelectionResult processingResult) {
+
+    transactionSelectionResults.updateNotSelected(
+        pendingTransaction.getTransaction(), processingResult);
+
+    // notify external selector if any
+    externalTransactionSelector.onTransactionRejected(pendingTransaction);
+  }
+
   /**
    * This method evaluates a transaction by pre-processing it through a series of selectors. It
    * first processes the transaction through internal selectors, and if the transaction is selected,

ethereum/blockcreation/src/test/java/org/hyperledger/besu/ethereum/blockcreation/AbstractBlockTransactionSelectorTest.java

@@ -19,6 +19,9 @@ import static org.assertj.core.api.Assertions.entry;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyBoolean;
 import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import org.hyperledger.besu.config.GenesisConfigFile;
@@ -33,6 +36,7 @@ import org.hyperledger.besu.ethereum.GasLimitCalculator;
 import org.hyperledger.besu.ethereum.ProtocolContext;
 import org.hyperledger.besu.ethereum.blockcreation.txselection.BlockTransactionSelector;
 import org.hyperledger.besu.ethereum.blockcreation.txselection.TransactionSelectionResults;
+import org.hyperledger.besu.ethereum.blockcreation.txselection.selectors.AllAcceptingTransactionSelector;
 import org.hyperledger.besu.ethereum.chain.DefaultBlockchain;
 import org.hyperledger.besu.ethereum.chain.GenesisState;
 import org.hyperledger.besu.ethereum.chain.MutableBlockchain;
@@ -84,6 +88,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Answers;
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.mockito.junit.jupiter.MockitoSettings;
@@ -659,6 +664,43 @@ public abstract class AbstractBlockTransactionSelectorTest {
         .containsOnly(entry(notSelected, TransactionSelectionResult.invalidTransient("Invalid")));
   }
 
+  @Test
+  public void transactionSelectionPluginShouldBeNotifiedWhenTransactionSelectionCompletes() {
+    final TransactionSelectorFactory transactionSelectorFactory =
+        mock(TransactionSelectorFactory.class);
+    TransactionSelector transactionSelector = spy(AllAcceptingTransactionSelector.INSTANCE);
+    when(transactionSelectorFactory.create()).thenReturn(transactionSelector);
+
+    final Transaction transaction = createTransaction(0, Wei.of(10), 21_000);
+    ensureTransactionIsValid(transaction, 21_000, 0);
+
+    final Transaction invalidTransaction = createTransaction(1, Wei.of(10), 21_000);
+    ensureTransactionIsInvalid(
+        invalidTransaction, TransactionInvalidReason.PLUGIN_TX_VALIDATOR_INVALIDATED);
+    transactionPool.addRemoteTransactions(List.of(transaction, invalidTransaction));
+
+    createBlockSelectorWithTxSelPlugin(
+            transactionProcessor,
+            createBlock(300_000),
+            Wei.ZERO,
+            AddressHelpers.ofValue(1),
+            Wei.ZERO,
+            MIN_OCCUPANCY_80_PERCENT,
+            transactionSelectorFactory)
+        .buildTransactionListForBlock();
+
+    ArgumentCaptor<PendingTransaction> argumentCaptor =
+        ArgumentCaptor.forClass(PendingTransaction.class);
+
+    verify(transactionSelector).onTransactionSelected(argumentCaptor.capture());
+    PendingTransaction selected = argumentCaptor.getValue();
+    assertThat(selected.getTransaction()).isEqualTo(transaction);
+
+    verify(transactionSelector).onTransactionRejected(argumentCaptor.capture());
+    PendingTransaction rejectedTransaction = argumentCaptor.getValue();
+    assertThat(rejectedTransaction.getTransaction()).isEqualTo(invalidTransaction);
+  }
+
   @Test
   public void transactionWithIncorrectNonceRemainsInPoolAndNotSelected() {
     final ProcessableBlockHeader blockHeader = createBlock(5_000_000);

plugin-api/build.gradle

@@ -69,7 +69,7 @@ Calculated : ${currentHash}
 tasks.register('checkAPIChanges', FileStateChecker) {
   description = "Checks that the API for the Plugin-API project does not change without deliberate thought"
   files = sourceSets.main.allJava.files
-  knownHash = '8NVdDoCnMQiibEZUsZuemZU+wm3W1LPklcQkiKsriKs='
+  knownHash = '+7wo9cABKEFyYvjtpDFAOXqVKBAkffdnb433hT0VQ7I='
 }
 check.dependsOn('checkAPIChanges')
 

plugin-api/src/main/java/org/hyperledger/besu/plugin/services/txselection/TransactionSelector.java

@@ -43,4 +43,17 @@ public interface TransactionSelector {
    */
   TransactionSelectionResult evaluateTransactionPostProcessing(
       PendingTransaction pendingTransaction, TransactionProcessingResult processingResult);
+
+  /**
+   * Method called when a transaction is selected to be added to a block.
+   *
+   * @param pendingTransaction The transaction that has been selected.
+   */
+  default void onTransactionSelected(final PendingTransaction pendingTransaction) {}
+  /**
+   * Method called when a transaction is rejected to be added to a block.
+   *
+   * @param pendingTransaction The transaction that has been rejected.
+   */
+  default void onTransactionRejected(final PendingTransaction pendingTransaction) {}
 }