Created listener for worker state change (#291)

* Created listener for worker state change
#275

src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/NoOpWorkerStateChangeListener.java

@@ -0,0 +1,16 @@
+package com.amazonaws.services.kinesis.clientlibrary.lib.worker;
+
+public class NoOpWorkerStateChangeListener implements WorkerStateChangeListener {
+
+	/**
+	 * Empty constructor for NoOp Worker State Change Listener
+	 */
+	public NoOpWorkerStateChangeListener() {
+
+	}
+
+	@Override
+	public void onWorkerStateChange(WorkerState newState) {
+
+	}
+}

src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/Worker.java

@@ -71,6 +71,7 @@ public class Worker implements Runnable {
     private static final Log LOG = LogFactory.getLog(Worker.class);
 
     private static final int MAX_INITIALIZATION_ATTEMPTS = 20;
+    private static final WorkerStateChangeListener DEFAULT_WORKER_STATE_CHANGE_LISTENER = new NoOpWorkerStateChangeListener();
 
     private WorkerLog wlog = new WorkerLog();
 
@@ -93,7 +94,6 @@ public class Worker implements Runnable {
     private final Optional<Integer> retryGetRecordsInSeconds;
     private final Optional<Integer> maxGetRecordsThreadPool;
 
-    // private final KinesisClientLeaseManager leaseManager;
     private final KinesisClientLibLeaseCoordinator leaseCoordinator;
     private final ShardSyncTaskManager controlServer;
 
@@ -119,6 +119,8 @@ public class Worker implements Runnable {
     @VisibleForTesting
     protected GracefulShutdownCoordinator gracefulShutdownCoordinator = new GracefulShutdownCoordinator();
 
+    private WorkerStateChangeListener workerStateChangeListener;
+
     /**
      * Constructor.
      *
@@ -276,7 +278,8 @@ public class Worker implements Runnable {
                 config.getSkipShardSyncAtWorkerInitializationIfLeasesExist(),
                 config.getShardPrioritizationStrategy(),
                 config.getRetryGetRecordsInSeconds(),
-                config.getMaxGetRecordsThreadPool());
+                config.getMaxGetRecordsThreadPool(),
+                DEFAULT_WORKER_STATE_CHANGE_LISTENER);
 
         // If a region name was explicitly specified, use it as the region for Amazon Kinesis and Amazon DynamoDB.
         if (config.getRegionName() != null) {
@@ -348,7 +351,7 @@ public class Worker implements Runnable {
         this(applicationName, recordProcessorFactory, config, streamConfig, initialPositionInStream, parentShardPollIntervalMillis,
                 shardSyncIdleTimeMillis, cleanupLeasesUponShardCompletion, checkpoint, leaseCoordinator, execService,
                 metricsFactory, taskBackoffTimeMillis, failoverTimeMillis, skipShardSyncAtWorkerInitializationIfLeasesExist,
-                shardPrioritization, Optional.empty(), Optional.empty());
+                shardPrioritization, Optional.empty(), Optional.empty(), DEFAULT_WORKER_STATE_CHANGE_LISTENER);
     }
 
     /**
@@ -395,7 +398,7 @@ public class Worker implements Runnable {
            KinesisClientLibLeaseCoordinator leaseCoordinator, ExecutorService execService,
            IMetricsFactory metricsFactory, long taskBackoffTimeMillis, long failoverTimeMillis,
            boolean skipShardSyncAtWorkerInitializationIfLeasesExist, ShardPrioritization shardPrioritization,
-           Optional<Integer> retryGetRecordsInSeconds, Optional<Integer> maxGetRecordsThreadPool) {
+           Optional<Integer> retryGetRecordsInSeconds, Optional<Integer> maxGetRecordsThreadPool, WorkerStateChangeListener workerStateChangeListener) {
         this.applicationName = applicationName;
         this.recordProcessorFactory = recordProcessorFactory;
         this.config = config;
@@ -417,6 +420,8 @@ public class Worker implements Runnable {
         this.shardPrioritization = shardPrioritization;
         this.retryGetRecordsInSeconds = retryGetRecordsInSeconds;
         this.maxGetRecordsThreadPool = maxGetRecordsThreadPool;
+        this.workerStateChangeListener = workerStateChangeListener;
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.CREATED);
     }
 
     /**
@@ -494,6 +499,7 @@ public class Worker implements Runnable {
     }
 
     private void initialize() {
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.INITIALIZING);
         boolean isDone = false;
         Exception lastException = null;
 
@@ -543,6 +549,7 @@ public class Worker implements Runnable {
         if (!isDone) {
             throw new RuntimeException(lastException);
         }
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.STARTED);
     }
 
     /**
@@ -755,6 +762,10 @@ public class Worker implements Runnable {
         return shardInfoShardConsumerMap;
     }
 
+    WorkerStateChangeListener getWorkerStateChangeListener() {
+        return workerStateChangeListener;
+    }
+
     /**
      * Signals worker to shutdown. Worker will try initiating shutdown of all record processors. Note that if executor
      * services were passed to the worker by the user, worker will not attempt to shutdown those resources.
@@ -785,6 +796,7 @@ public class Worker implements Runnable {
         // Lost leases will force Worker to begin shutdown process for all shard consumers in
         // Worker.run().
         leaseCoordinator.stop();
+        workerStateChangeListener.onWorkerStateChange(WorkerStateChangeListener.WorkerState.SHUT_DOWN);
     }
 
     /**
@@ -1089,6 +1101,7 @@ public class Worker implements Runnable {
         private ExecutorService execService;
         private ShardPrioritization shardPrioritization;
         private IKinesisProxy kinesisProxy;
+        private WorkerStateChangeListener workerStateChangeListener;
 
         /**
          * Default constructor.
@@ -1233,6 +1246,17 @@ public class Worker implements Runnable {
             return this;
         }
 
+        /**
+         * Set WorkerStateChangeListener for the worker
+         * @param workerStateChangeListener
+         *             Sets the WorkerStateChangeListener
+         * @return A reference to this updated object so that method calls can be chained together.
+         */
+        public Builder workerStateChangeListener(WorkerStateChangeListener workerStateChangeListener) {
+            this.workerStateChangeListener = workerStateChangeListener;
+            return this;
+        }
+
         /**
          * Build the Worker instance.
          *
@@ -1305,6 +1329,10 @@ public class Worker implements Runnable {
                 kinesisProxy = new KinesisProxy(config, kinesisClient);
             }
 
+            if (workerStateChangeListener == null) {
+                workerStateChangeListener = DEFAULT_WORKER_STATE_CHANGE_LISTENER;
+            }
+
             return new Worker(config.getApplicationName(),
                     recordProcessorFactory,
                     config,
@@ -1336,9 +1364,8 @@ public class Worker implements Runnable {
                     config.getSkipShardSyncAtWorkerInitializationIfLeasesExist(),
                     shardPrioritization,
                     config.getRetryGetRecordsInSeconds(),
-                    config.getMaxGetRecordsThreadPool());
+                    config.getMaxGetRecordsThreadPool(),
-
+                    workerStateChangeListener);
-        }
+        }
-
     }
 }

src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/WorkerStateChangeListener.java

@@ -0,0 +1,16 @@
+package com.amazonaws.services.kinesis.clientlibrary.lib.worker;
+
+/**
+ * A listener for callbacks on changes worker state
+ */
+@FunctionalInterface
+public interface WorkerStateChangeListener {
+	enum WorkerState {
+		CREATED,
+		INITIALIZING,
+		STARTED,
+		SHUT_DOWN
+	}
+
+	void onWorkerStateChange(WorkerState newState);
+}

src/test/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/WorkerTest.java

@@ -22,6 +22,7 @@ import static org.hamcrest.Matchers.greaterThanOrEqualTo;
 import static org.junit.Assert.fail;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyLong;
 import static org.mockito.Matchers.anyString;
 import static org.mockito.Matchers.argThat;
 import static org.mockito.Matchers.eq;
@@ -89,6 +90,7 @@ import com.amazonaws.services.kinesis.clientlibrary.interfaces.v2.IRecordProcess
 import com.amazonaws.services.kinesis.clientlibrary.interfaces.v2.IRecordProcessorFactory;
 import com.amazonaws.services.kinesis.clientlibrary.lib.worker.Worker.WorkerCWMetricsFactory;
 import com.amazonaws.services.kinesis.clientlibrary.lib.worker.Worker.WorkerThreadPoolExecutor;
+import com.amazonaws.services.kinesis.clientlibrary.lib.worker.WorkerStateChangeListener.WorkerState;
 import com.amazonaws.services.kinesis.clientlibrary.proxies.IKinesisProxy;
 import com.amazonaws.services.kinesis.clientlibrary.proxies.KinesisProxy;
 import com.amazonaws.services.kinesis.clientlibrary.proxies.KinesisLocalFileProxy;
@@ -170,6 +172,8 @@ public class WorkerTest {
     private Future<TaskResult> taskFuture;
     @Mock
     private TaskResult taskResult;
+    @Mock
+    private WorkerStateChangeListener workerStateChangeListener;
 
     @Before
     public void setup() {
@@ -1500,6 +1504,105 @@ public class WorkerTest {
         Assert.assertTrue(worker.getStreamConfig().getStreamProxy() instanceof KinesisLocalFileProxy);
     }
 
+    @Test
+    public void testBuilderForWorkerStateListener() {
+        IRecordProcessorFactory recordProcessorFactory = mock(IRecordProcessorFactory.class);
+        Worker worker = new Worker.Builder()
+                .recordProcessorFactory(recordProcessorFactory)
+                .config(config)
+                .build();
+        Assert.assertTrue(worker.getWorkerStateChangeListener() instanceof NoOpWorkerStateChangeListener);
+    }
+
+    @Test
+    public void testBuilderWhenWorkerStateListenerIsSet() {
+        IRecordProcessorFactory recordProcessorFactory = mock(IRecordProcessorFactory.class);
+        Worker worker = new Worker.Builder()
+                .recordProcessorFactory(recordProcessorFactory)
+                .workerStateChangeListener(workerStateChangeListener)
+                .config(config)
+                .build();
+        Assert.assertSame(workerStateChangeListener, worker.getWorkerStateChangeListener());
+    }
+
+    @Test
+    public void testWorkerStateListenerStatePassesThroughCreatedState() {
+        IRecordProcessorFactory recordProcessorFactory = mock(IRecordProcessorFactory.class);
+        new Worker.Builder()
+                .recordProcessorFactory(recordProcessorFactory)
+                .workerStateChangeListener(workerStateChangeListener)
+                .config(config)
+                .build();
+
+        verify(workerStateChangeListener, times(1)).onWorkerStateChange(eq(WorkerState.CREATED));
+    }
+
+    @Test
+    public void testWorkerStateChangeListenerGoesThroughStates() throws Exception {
+
+        final CountDownLatch workerInitialized = new CountDownLatch(1);
+        final CountDownLatch workerStarted = new CountDownLatch(1);
+        final IRecordProcessorFactory recordProcessorFactory = mock(IRecordProcessorFactory.class);
+        final IRecordProcessor processor = mock(IRecordProcessor.class);
+
+        ExtendedSequenceNumber checkpoint = new ExtendedSequenceNumber("123", 0L);
+        KinesisClientLeaseBuilder builder = new KinesisClientLeaseBuilder().withCheckpoint(checkpoint)
+                .withConcurrencyToken(UUID.randomUUID()).withLastCounterIncrementNanos(0L).withLeaseCounter(0L)
+                .withOwnerSwitchesSinceCheckpoint(0L).withLeaseOwner("Self");
+        final List<KinesisClientLease> leases = new ArrayList<>();
+        KinesisClientLease lease = builder.withLeaseKey(String.format("shardId-%03d", 1)).build();
+        leases.add(lease);
+
+        doAnswer(new Answer<Boolean>() {
+            @Override
+            public Boolean answer(InvocationOnMock invocation) throws Throwable {
+                workerInitialized.countDown();
+                return true;
+            }
+        }).when(leaseManager).waitUntilLeaseTableExists(anyLong(), anyLong());
+        doAnswer(new Answer<IRecordProcessor>() {
+            @Override
+            public IRecordProcessor answer(InvocationOnMock invocation) throws Throwable {
+                workerStarted.countDown();
+                return processor;
+            }
+        }).when(recordProcessorFactory).createProcessor();
+
+        when(config.getWorkerIdentifier()).thenReturn("Self");
+        when(leaseManager.listLeases()).thenReturn(leases);
+        when(leaseManager.renewLease(leases.get(0))).thenReturn(true);
+        when(executorService.submit(Matchers.<Callable<TaskResult>> any()))
+                .thenAnswer(new ShutdownHandlingAnswer(taskFuture));
+        when(taskFuture.isDone()).thenReturn(true);
+        when(taskFuture.get()).thenReturn(taskResult);
+        when(taskResult.isShardEndReached()).thenReturn(true);
+
+        Worker worker = new Worker.Builder()
+                .recordProcessorFactory(recordProcessorFactory)
+                .config(config)
+                .leaseManager(leaseManager)
+                .kinesisProxy(kinesisProxy)
+                .execService(executorService)
+                .workerStateChangeListener(workerStateChangeListener)
+                .build();
+
+        verify(workerStateChangeListener, times(1)).onWorkerStateChange(eq(WorkerState.CREATED));
+
+        WorkerThread workerThread = new WorkerThread(worker);
+        workerThread.start();
+
+        workerInitialized.await();
+        verify(workerStateChangeListener, times(1)).onWorkerStateChange(eq(WorkerState.INITIALIZING));
+
+        workerStarted.await();
+        verify(workerStateChangeListener, times(1)).onWorkerStateChange(eq(WorkerState.STARTED));
+
+        boolean workerShutdown = worker.createGracefulShutdownCallable()
+                .call();
+
+        verify(workerStateChangeListener, times(1)).onWorkerStateChange(eq(WorkerState.SHUT_DOWN));
+    }
+
     @Test
     public void testBuilderWithDefaultLeaseManager()  {
         IRecordProcessorFactory recordProcessorFactory = mock(IRecordProcessorFactory.class);