Split IbftProcessor into looping and event processing (#612)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

consensus/ibft/src/main/java/tech/pegasys/pantheon/consensus/ibft/EventMultiplexer.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2019 ConsenSys AG.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package tech.pegasys.pantheon.consensus.ibft;
+
+import tech.pegasys.pantheon.consensus.ibft.ibftevent.BlockTimerExpiry;
+import tech.pegasys.pantheon.consensus.ibft.ibftevent.IbftEvent;
+import tech.pegasys.pantheon.consensus.ibft.ibftevent.IbftReceivedMessageEvent;
+import tech.pegasys.pantheon.consensus.ibft.ibftevent.NewChainHead;
+import tech.pegasys.pantheon.consensus.ibft.ibftevent.RoundExpiry;
+import tech.pegasys.pantheon.consensus.ibft.statemachine.IbftController;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+public class EventMultiplexer {
+
+  private static final Logger LOG = LogManager.getLogger();
+
+  private final IbftController ibftController;
+
+  public EventMultiplexer(final IbftController ibftController) {
+    this.ibftController = ibftController;
+  }
+
+  public void handleIbftEvent(final IbftEvent ibftEvent) {
+    try {
+      switch (ibftEvent.getType()) {
+        case MESSAGE:
+          final IbftReceivedMessageEvent rxEvent = (IbftReceivedMessageEvent) ibftEvent;
+          ibftController.handleMessageEvent(rxEvent);
+          break;
+        case ROUND_EXPIRY:
+          final RoundExpiry roundExpiryEvent = (RoundExpiry) ibftEvent;
+          ibftController.handleRoundExpiry(roundExpiryEvent);
+          break;
+        case NEW_CHAIN_HEAD:
+          final NewChainHead newChainHead = (NewChainHead) ibftEvent;
+          ibftController.handleNewBlockEvent(newChainHead);
+          break;
+        case BLOCK_TIMER_EXPIRY:
+          final BlockTimerExpiry blockTimerExpiry = (BlockTimerExpiry) ibftEvent;
+          ibftController.handleBlockTimerExpiry(blockTimerExpiry);
+          break;
+        default:
+          throw new RuntimeException("Illegal event in queue.");
+      }
+    } catch (final Exception e) {
+      LOG.error("State machine threw exception while processing event {" + ibftEvent + "}", e);
+    }
+  }
+}

consensus/ibft/src/main/java/tech/pegasys/pantheon/consensus/ibft/IbftProcessor.java

@@ -12,12 +12,7 @@
  */
 package tech.pegasys.pantheon.consensus.ibft;
 
-import tech.pegasys.pantheon.consensus.ibft.ibftevent.BlockTimerExpiry;
 import tech.pegasys.pantheon.consensus.ibft.ibftevent.IbftEvent;
-import tech.pegasys.pantheon.consensus.ibft.ibftevent.IbftReceivedMessageEvent;
-import tech.pegasys.pantheon.consensus.ibft.ibftevent.NewChainHead;
-import tech.pegasys.pantheon.consensus.ibft.ibftevent.RoundExpiry;
-import tech.pegasys.pantheon.consensus.ibft.statemachine.IbftController;
 
 import java.util.Optional;
 import java.util.concurrent.Executors;
@@ -30,39 +25,37 @@ import org.apache.logging.log4j.Logger;
 
 /** Execution context for draining queued ibft events and applying them to a maintained state */
 public class IbftProcessor implements Runnable {
+
   private static final Logger LOG = LogManager.getLogger();
 
   private final IbftEventQueue incomingQueue;
   private final ScheduledExecutorService roundTimerExecutor;
   private volatile boolean shutdown = false;
-  private final IbftController ibftController;
+  private final EventMultiplexer eventMultiplexer;
 
   /**
    * Construct a new IbftProcessor
    *
    * @param incomingQueue The event queue from which to drain new events
-   * @param ibftController an object capable of handling any/all IBFT events
+   * @param eventMultiplexer an object capable of handling any/all IBFT events
    */
-  public IbftProcessor(final IbftEventQueue incomingQueue, final IbftController ibftController) {
+  public IbftProcessor(
+      final IbftEventQueue incomingQueue, final EventMultiplexer eventMultiplexer) {
     // Spawning the round timer with a single thread as we should never have more than 1 timer in
     // flight at a time
-    this(incomingQueue, ibftController, Executors.newSingleThreadScheduledExecutor());
+    this(incomingQueue, eventMultiplexer, Executors.newSingleThreadScheduledExecutor());
   }
 
   @VisibleForTesting
   IbftProcessor(
       final IbftEventQueue incomingQueue,
-      final IbftController ibftController,
+      final EventMultiplexer eventMultiplexer,
       final ScheduledExecutorService roundTimerExecutor) {
     this.incomingQueue = incomingQueue;
-    this.ibftController = ibftController;
+    this.eventMultiplexer = eventMultiplexer;
     this.roundTimerExecutor = roundTimerExecutor;
   }
 
-  public void start() {
-    ibftController.start();
-  }
-
   /** Indicate to the processor that it should gracefully stop at its next opportunity */
   public void stop() {
     shutdown = true;
@@ -71,39 +64,12 @@ public class IbftProcessor implements Runnable {
   @Override
   public void run() {
     while (!shutdown) {
-      nextIbftEvent().ifPresent(this::handleIbftEvent);
+      nextIbftEvent().ifPresent(event -> eventMultiplexer.handleIbftEvent(event));
     }
     // Clean up the executor service the round timer has been utilising
     roundTimerExecutor.shutdownNow();
   }
 
-  private void handleIbftEvent(final IbftEvent ibftEvent) {
-    try {
-      switch (ibftEvent.getType()) {
-        case MESSAGE:
-          final IbftReceivedMessageEvent rxEvent = (IbftReceivedMessageEvent) ibftEvent;
-          ibftController.handleMessageEvent(rxEvent);
-          break;
-        case ROUND_EXPIRY:
-          final RoundExpiry roundExpiryEvent = (RoundExpiry) ibftEvent;
-          ibftController.handleRoundExpiry(roundExpiryEvent);
-          break;
-        case NEW_CHAIN_HEAD:
-          final NewChainHead newChainHead = (NewChainHead) ibftEvent;
-          ibftController.handleNewBlockEvent(newChainHead);
-          break;
-        case BLOCK_TIMER_EXPIRY:
-          final BlockTimerExpiry blockTimerExpiry = (BlockTimerExpiry) ibftEvent;
-          ibftController.handleBlockTimerExpiry(blockTimerExpiry);
-          break;
-        default:
-          throw new RuntimeException("Illegal event in queue.");
-      }
-    } catch (final Exception e) {
-      LOG.error("State machine threw exception while processing event {" + ibftEvent + "}", e);
-    }
-  }
-
   private Optional<IbftEvent> nextIbftEvent() {
     try {
       return Optional.ofNullable(incomingQueue.poll(500, TimeUnit.MILLISECONDS));

consensus/ibft/src/main/java/tech/pegasys/pantheon/consensus/ibft/blockcreation/IbftMiningCoordinator.java

@@ -48,10 +48,7 @@ public class IbftMiningCoordinator implements MiningCoordinator, BlockAddedObser
   }
 
   @Override
-  public void enable() {
-    ibftProcessor.start();
-    // IbftProcessor is implicitly running (but maybe should have a discard" all)
-  }
+  public void enable() {}
 
   @Override
   public void disable() {

consensus/ibft/src/test/java/tech/pegasys/pantheon/consensus/ibft/IbftProcessorTest.java

@@ -23,7 +23,6 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 import tech.pegasys.pantheon.consensus.ibft.ibftevent.RoundExpiry;
-import tech.pegasys.pantheon.consensus.ibft.statemachine.IbftController;
 
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -40,12 +39,12 @@ import org.mockito.junit.MockitoJUnitRunner;
 @RunWith(MockitoJUnitRunner.StrictStubs.class)
 public class IbftProcessorTest {
   private ScheduledExecutorService mockExecutorService;
-  private IbftController mockIbftController;
+  private EventMultiplexer mockeEventMultiplexer;
 
   @Before
   public void initialise() {
     mockExecutorService = mock(ScheduledExecutorService.class);
-    mockIbftController = mock(IbftController.class);
+    mockeEventMultiplexer = mock(EventMultiplexer.class);
   }
 
   @Test
@@ -53,7 +52,7 @@ public class IbftProcessorTest {
     final IbftEventQueue mockQueue = mock(IbftEventQueue.class);
     Mockito.when(mockQueue.poll(anyLong(), any())).thenReturn(null);
     final IbftProcessor processor =
-        new IbftProcessor(mockQueue, mockIbftController, mockExecutorService);
+        new IbftProcessor(mockQueue, mockeEventMultiplexer, mockExecutorService);
 
     // Start the IbftProcessor
     final ExecutorService processorExecutor = Executors.newSingleThreadExecutor();
@@ -82,7 +81,7 @@ public class IbftProcessorTest {
   @Test
   public void cleanupExecutorsAfterShutdownNow() throws InterruptedException {
     final IbftProcessor processor =
-        new IbftProcessor(new IbftEventQueue(), mockIbftController, mockExecutorService);
+        new IbftProcessor(new IbftEventQueue(), mockeEventMultiplexer, mockExecutorService);
 
     // Start the IbftProcessor
     final ExecutorService processorExecutor = Executors.newSingleThreadExecutor();
@@ -112,7 +111,7 @@ public class IbftProcessorTest {
     Mockito.when(mockQueue.poll(anyLong(), any())).thenThrow(new InterruptedException());
 
     final IbftProcessor processor =
-        new IbftProcessor(mockQueue, mockIbftController, mockExecutorService);
+        new IbftProcessor(mockQueue, mockeEventMultiplexer, mockExecutorService);
 
     // Start the IbftProcessor
     final ExecutorService processorExecutor = Executors.newSingleThreadExecutor();
@@ -145,7 +144,7 @@ public class IbftProcessorTest {
   public void drainEventsIntoStateMachine() throws InterruptedException {
     final IbftEventQueue queue = new IbftEventQueue();
     final IbftProcessor processor =
-        new IbftProcessor(queue, mockIbftController, mockExecutorService);
+        new IbftProcessor(queue, mockeEventMultiplexer, mockExecutorService);
 
     // Start the IbftProcessor
     final ExecutorService processorExecutor = Executors.newSingleThreadExecutor();
@@ -161,6 +160,6 @@ public class IbftProcessorTest {
     processor.stop();
     processorExecutor.shutdown();
 
-    verify(mockIbftController, times(2)).handleRoundExpiry(eq(roundExpiryEvent));
+    verify(mockeEventMultiplexer, times(2)).handleIbftEvent(eq(roundExpiryEvent));
   }
 }

consensus/ibft/src/test/java/tech/pegasys/pantheon/consensus/ibft/blockcreation/IbftMiningCoordinatorTest.java

@@ -59,7 +59,6 @@ public class IbftMiningCoordinatorTest {
   @Test
   public void enablesMining() {
     ibftMiningCoordinator.enable();
-    verify(ibftProcessor).start();
   }
 
   @Test

pantheon/src/main/java/tech/pegasys/pantheon/controller/IbftPantheonController.java

@@ -22,6 +22,7 @@ import tech.pegasys.pantheon.consensus.common.VoteProposer;
 import tech.pegasys.pantheon.consensus.common.VoteTally;
 import tech.pegasys.pantheon.consensus.common.VoteTallyUpdater;
 import tech.pegasys.pantheon.consensus.ibft.BlockTimer;
+import tech.pegasys.pantheon.consensus.ibft.EventMultiplexer;
 import tech.pegasys.pantheon.consensus.ibft.IbftBlockInterface;
 import tech.pegasys.pantheon.consensus.ibft.IbftContext;
 import tech.pegasys.pantheon.consensus.ibft.IbftEventQueue;
@@ -236,8 +237,10 @@ public class IbftPantheonController implements PantheonController<IbftContext> {
                 new IbftRoundFactory(
                     finalState, protocolContext, protocolSchedule, minedBlockObservers),
                 messageValidatorFactory));
+    ibftController.start();
 
-    final IbftProcessor ibftProcessor = new IbftProcessor(ibftEventQueue, ibftController);
+    final EventMultiplexer eventMultiplexer = new EventMultiplexer(ibftController);
+    final IbftProcessor ibftProcessor = new IbftProcessor(ibftEventQueue, eventMultiplexer);
     final ExecutorService processorExecutor = Executors.newSingleThreadExecutor();
     processorExecutor.submit(ibftProcessor);