7311: Return Optional<EthPeer> in PeerSelector.getPeer and utilise existing peer selection behavior in EthPeers

Signed-off-by: Matilda Clerke <matilda.clerke@consensys.net>

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/manager/EthPeers.java

@@ -17,7 +17,6 @@ package org.hyperledger.besu.ethereum.eth.manager;
 import org.hyperledger.besu.ethereum.core.BlockHeader;
 import org.hyperledger.besu.ethereum.eth.SnapProtocol;
 import org.hyperledger.besu.ethereum.eth.manager.EthPeer.DisconnectCallback;
-import org.hyperledger.besu.ethereum.eth.manager.exceptions.NoAvailablePeersException;
 import org.hyperledger.besu.ethereum.eth.manager.peertask.PeerSelector;
 import org.hyperledger.besu.ethereum.eth.peervalidation.PeerValidator;
 import org.hyperledger.besu.ethereum.eth.sync.ChainHeadTracker;
@@ -470,8 +469,8 @@ public class EthPeers implements PeerSelector {
 
   // Part of the PeerSelector interface, to be split apart later
   @Override
-  public EthPeer getPeer(final Predicate<EthPeer> filter) {
-    return streamBestPeers().filter(filter).findFirst().orElseThrow(NoAvailablePeersException::new);
+  public Optional<EthPeer> getPeer(final Predicate<EthPeer> filter) {
+    return bestPeerMatchingCriteria(filter);
   }
 
   // Part of the PeerSelector interface, to be split apart later

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/manager/peertask/PeerSelector.java

@@ -29,7 +29,7 @@ public interface PeerSelector {
    * @param filter a Predicate\<EthPeer\> matching desirable peers
    * @return a peer matching the supplied conditions
    */
-  EthPeer getPeer(final Predicate<EthPeer> filter);
+  Optional<EthPeer> getPeer(final Predicate<EthPeer> filter);
 
   /**
    * Attempts to get the EthPeer identified by peerId

ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/manager/peertask/PeerTaskExecutor.java

@@ -15,7 +15,6 @@
 package org.hyperledger.besu.ethereum.eth.manager.peertask;
 
 import org.hyperledger.besu.ethereum.eth.manager.EthPeer;
-import org.hyperledger.besu.ethereum.eth.manager.exceptions.NoAvailablePeersException;
 import org.hyperledger.besu.ethereum.p2p.rlpx.connections.PeerConnection;
 import org.hyperledger.besu.ethereum.p2p.rlpx.wire.MessageData;
 import org.hyperledger.besu.metrics.BesuMetricCategory;
@@ -62,20 +61,19 @@ public class PeerTaskExecutor {
             : NO_RETRIES;
     final Collection<EthPeer> usedEthPeers = new HashSet<>();
     do {
-      EthPeer peer;
-      try {
-        peer =
+      Optional<EthPeer> peer =
           peerSelector.getPeer(
               (candidatePeer) ->
                   peerTask.getPeerRequirementFilter().test(candidatePeer)
                       && !usedEthPeers.contains(candidatePeer));
-        usedEthPeers.add(peer);
-        executorResult = executeAgainstPeer(peerTask, peer);
-      } catch (NoAvailablePeersException e) {
+      if (peer.isEmpty()) {
         executorResult =
             new PeerTaskExecutorResult<>(
                 Optional.empty(), PeerTaskExecutorResponseCode.NO_PEER_AVAILABLE);
+        continue;
       }
+      usedEthPeers.add(peer.get());
+      executorResult = executeAgainstPeer(peerTask, peer.get());
     } while (retriesRemaining-- > 0
         && executorResult.responseCode() != PeerTaskExecutorResponseCode.SUCCESS);
 

ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/manager/peertask/PeerTaskExecutorTest.java

@@ -22,6 +22,7 @@ import org.hyperledger.besu.metrics.noop.NoOpMetricsSystem;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeoutException;
 import java.util.function.Predicate;
@@ -49,8 +50,7 @@ public class PeerTaskExecutorTest {
   @BeforeEach
   public void beforeTest() {
     mockCloser = MockitoAnnotations.openMocks(this);
-    peerTaskExecutor =
-        new PeerTaskExecutor(peerSelector, requestSender, new NoOpMetricsSystem());
+    peerTaskExecutor = new PeerTaskExecutor(peerSelector, requestSender, new NoOpMetricsSystem());
   }
 
   @AfterEach
@@ -201,7 +201,8 @@ public class PeerTaskExecutorTest {
           InvalidPeerTaskResponseException {
     Object responseObject = new Object();
 
-    Mockito.when(peerSelector.getPeer(Mockito.any(Predicate.class))).thenReturn(ethPeer);
+    Mockito.when(peerSelector.getPeer(Mockito.any(Predicate.class)))
+        .thenReturn(Optional.of(ethPeer));
 
     Mockito.when(peerTask.getRequestMessage()).thenReturn(requestMessageData);
     Mockito.when(peerTask.getPeerTaskRetryBehaviors()).thenReturn(Collections.emptyList());
@@ -234,8 +235,8 @@ public class PeerTaskExecutorTest {
     EthPeer peer2 = Mockito.mock(EthPeer.class);
 
     Mockito.when(peerSelector.getPeer(Mockito.any(Predicate.class)))
-        .thenReturn(ethPeer)
-        .thenReturn(peer2);
+        .thenReturn(Optional.of(ethPeer))
+        .thenReturn(Optional.of(peer2));
 
     Mockito.when(peerTask.getRequestMessage()).thenReturn(requestMessageData);
     Mockito.when(peerTask.getPeerTaskRetryBehaviors())