org.apache.flink.queryablestate.network.messages.MessageSerializer Java Examples

/**
 * Creates an established connection with the given channel.
 *
 * @param serverAddress Address of the server connected to
 * @param channel The actual TCP channel
 */
EstablishedConnection(
		final InetSocketAddress serverAddress,
		final MessageSerializer<REQ, RESP> serializer,
		final Channel channel) {

	this.serverAddress = Preconditions.checkNotNull(serverAddress);
	this.channel = Preconditions.checkNotNull(channel);

	// Add the client handler with the callback
	channel.pipeline().addLast(
			getClientName() + " Handler",
			new ClientHandler<>(clientName, serializer, this)
	);

	stats.reportActiveConnection();
}
 

/**
 * Tests request serialization.
 */
@Test
public void testRequestSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 1337L;
	KvStateID kvStateId = new KvStateID();
	byte[] serializedKeyAndNamespace = randomByteArray(1024);

	final KvStateInternalRequest request = new KvStateInternalRequest(kvStateId, serializedKeyAndNamespace);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeRequest(alloc, requestId, request);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateInternalRequest requestDeser = serializer.deserializeRequest(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(kvStateId, requestDeser.getKvStateId());
	assertArrayEquals(serializedKeyAndNamespace, requestDeser.getSerializedKeyAndNamespace());
}
 

@Override
public AbstractServerHandler<TestMessage, TestMessage> initializeHandler() {
	return new AbstractServerHandler<TestMessage, TestMessage>(
			this,
			new MessageSerializer<>(new TestMessage.TestMessageDeserializer(), new TestMessage.TestMessageDeserializer()),
			requestStats) {

		@Override
		public CompletableFuture<TestMessage> handleRequest(long requestId, TestMessage request) {
			TestMessage response = new TestMessage(getServerName() + '-' + request.getMessage());
			return CompletableFuture.completedFuture(response);
		}

		@Override
		public CompletableFuture<Void> shutdown() {
			return CompletableFuture.completedFuture(null);
		}
	};
}
 

/**
 * Tests request serialization with zero-length serialized key and namespace.
 */
@Test
public void testRequestSerializationWithZeroLengthKeyAndNamespace() throws Exception {

	long requestId = Integer.MAX_VALUE + 1337L;
	KvStateID kvStateId = new KvStateID();
	byte[] serializedKeyAndNamespace = new byte[0];

	final KvStateInternalRequest request = new KvStateInternalRequest(kvStateId, serializedKeyAndNamespace);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeRequest(alloc, requestId, request);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateInternalRequest requestDeser = serializer.deserializeRequest(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(kvStateId, requestDeser.getKvStateId());
	assertArrayEquals(serializedKeyAndNamespace, requestDeser.getSerializedKeyAndNamespace());
}
 

/**
 * Tests response serialization with zero-length serialized result.
 */
@Test
public void testResponseSerializationWithZeroLengthSerializedResult() throws Exception {
	byte[] serializedResult = new byte[0];

	final KvStateResponse response = new KvStateResponse(serializedResult);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeResponse(alloc, 72727278L, response);

	int frameLength = buf.readInt();

	assertEquals(MessageType.REQUEST_RESULT, MessageSerializer.deserializeHeader(buf));
	assertEquals(72727278L, MessageSerializer.getRequestId(buf));
	KvStateResponse responseDeser = serializer.deserializeResponse(buf);
	assertEquals(buf.readerIndex(), frameLength + 4);

	assertArrayEquals(serializedResult, responseDeser.getContent());
}
 

/**
 * Tests request serialization.
 */
@Test
public void testRequestSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 1337L;
	KvStateID kvStateId = new KvStateID();
	byte[] serializedKeyAndNamespace = randomByteArray(1024);

	final KvStateInternalRequest request = new KvStateInternalRequest(kvStateId, serializedKeyAndNamespace);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeRequest(alloc, requestId, request);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateInternalRequest requestDeser = serializer.deserializeRequest(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(kvStateId, requestDeser.getKvStateId());
	assertArrayEquals(serializedKeyAndNamespace, requestDeser.getSerializedKeyAndNamespace());
}
 

/**
 * Tests request serialization with zero-length serialized key and namespace.
 */
@Test
public void testRequestSerializationWithZeroLengthKeyAndNamespace() throws Exception {

	long requestId = Integer.MAX_VALUE + 1337L;
	KvStateID kvStateId = new KvStateID();
	byte[] serializedKeyAndNamespace = new byte[0];

	final KvStateInternalRequest request = new KvStateInternalRequest(kvStateId, serializedKeyAndNamespace);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeRequest(alloc, requestId, request);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateInternalRequest requestDeser = serializer.deserializeRequest(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(kvStateId, requestDeser.getKvStateId());
	assertArrayEquals(serializedKeyAndNamespace, requestDeser.getSerializedKeyAndNamespace());
}
 

/**
 * Tests response serialization.
 */
@Test
public void testResponseSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 72727278L;
	byte[] serializedResult = randomByteArray(1024);

	final KvStateResponse response = new KvStateResponse(serializedResult);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeResponse(alloc, requestId, response);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST_RESULT, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateResponse responseDeser = serializer.deserializeResponse(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertArrayEquals(serializedResult, responseDeser.getContent());
}
 

/**
 * Tests response serialization with zero-length serialized result.
 */
@Test
public void testResponseSerializationWithZeroLengthSerializedResult() throws Exception {
	byte[] serializedResult = new byte[0];

	final KvStateResponse response = new KvStateResponse(serializedResult);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeResponse(alloc, 72727278L, response);

	int frameLength = buf.readInt();

	assertEquals(MessageType.REQUEST_RESULT, MessageSerializer.deserializeHeader(buf));
	assertEquals(72727278L, MessageSerializer.getRequestId(buf));
	KvStateResponse responseDeser = serializer.deserializeResponse(buf);
	assertEquals(buf.readerIndex(), frameLength + 4);

	assertArrayEquals(serializedResult, responseDeser.getContent());
}
 

/**
 * Tests request failure serialization.
 */
@Test
public void testKvStateRequestFailureSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 1111222L;
	IllegalStateException cause = new IllegalStateException("Expected test");

	ByteBuf buf = MessageSerializer.serializeRequestFailure(alloc, requestId, cause);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST_FAILURE, MessageSerializer.deserializeHeader(buf));
	RequestFailure requestFailure = MessageSerializer.deserializeRequestFailure(buf);
	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(requestId, requestFailure.getRequestId());
	assertEquals(cause.getClass(), requestFailure.getCause().getClass());
	assertEquals(cause.getMessage(), requestFailure.getCause().getMessage());
}
 

/**
 * Tests request serialization.
 */
@Test
public void testRequestSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 1337L;
	KvStateID kvStateId = new KvStateID();
	byte[] serializedKeyAndNamespace = randomByteArray(1024);

	final KvStateInternalRequest request = new KvStateInternalRequest(kvStateId, serializedKeyAndNamespace);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeRequest(alloc, requestId, request);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateInternalRequest requestDeser = serializer.deserializeRequest(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(kvStateId, requestDeser.getKvStateId());
	assertArrayEquals(serializedKeyAndNamespace, requestDeser.getSerializedKeyAndNamespace());
}
 

/**
 * Tests request serialization with zero-length serialized key and namespace.
 */
@Test
public void testRequestSerializationWithZeroLengthKeyAndNamespace() throws Exception {

	long requestId = Integer.MAX_VALUE + 1337L;
	KvStateID kvStateId = new KvStateID();
	byte[] serializedKeyAndNamespace = new byte[0];

	final KvStateInternalRequest request = new KvStateInternalRequest(kvStateId, serializedKeyAndNamespace);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeRequest(alloc, requestId, request);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateInternalRequest requestDeser = serializer.deserializeRequest(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(kvStateId, requestDeser.getKvStateId());
	assertArrayEquals(serializedKeyAndNamespace, requestDeser.getSerializedKeyAndNamespace());
}
 

/**
 * Tests response serialization.
 */
@Test
public void testResponseSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 72727278L;
	byte[] serializedResult = randomByteArray(1024);

	final KvStateResponse response = new KvStateResponse(serializedResult);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeResponse(alloc, requestId, response);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST_RESULT, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateResponse responseDeser = serializer.deserializeResponse(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertArrayEquals(serializedResult, responseDeser.getContent());
}
 

@Override
public AbstractServerHandler<TestMessage, TestMessage> initializeHandler() {
	return new AbstractServerHandler<TestMessage, TestMessage>(
			this,
			new MessageSerializer<>(new TestMessage.TestMessageDeserializer(), new TestMessage.TestMessageDeserializer()),
			requestStats) {

		@Override
		public CompletableFuture<TestMessage> handleRequest(long requestId, TestMessage request) {
			TestMessage response = new TestMessage(getServerName() + '-' + request.getMessage());
			return CompletableFuture.completedFuture(response);
		}

		@Override
		public CompletableFuture<Void> shutdown() {
			return CompletableFuture.completedFuture(null);
		}
	};
}
 

@Override
public AbstractServerHandler<TestMessage, TestMessage> initializeHandler() {
	return new AbstractServerHandler<TestMessage, TestMessage>(
			this,
			new MessageSerializer<>(new TestMessage.TestMessageDeserializer(), new TestMessage.TestMessageDeserializer()),
			requestStats) {

		@Override
		public CompletableFuture<TestMessage> handleRequest(long requestId, TestMessage request) {
			TestMessage response = new TestMessage(getServerName() + '-' + request.getMessage());
			return CompletableFuture.completedFuture(response);
		}

		@Override
		public CompletableFuture<Void> shutdown() {
			return CompletableFuture.completedFuture(null);
		}
	};
}
 

/**
 * Create the Queryable State Client.
 * @param remoteAddress the {@link InetAddress address} of the {@code Client Proxy} to connect to.
 * @param remotePort the port of the proxy to connect to.
 */
public QueryableStateClient(final InetAddress remoteAddress, final int remotePort) {
	Preconditions.checkArgument(NetUtils.isValidHostPort(remotePort),
			"Remote Port " + remotePort + " is out of valid port range [0-65535].");

	this.remoteAddress = new InetSocketAddress(remoteAddress, remotePort);

	final MessageSerializer<KvStateRequest, KvStateResponse> messageSerializer =
			new MessageSerializer<>(
					new KvStateRequest.KvStateRequestDeserializer(),
					new KvStateResponse.KvStateResponseDeserializer());

	this.client = new Client<>(
			"Queryable State Client",
			1,
			messageSerializer,
			new DisabledKvStateRequestStats());
}
 

/**
 * Creates an established connection with the given channel.
 *
 * @param serverAddress Address of the server connected to
 * @param channel The actual TCP channel
 */
EstablishedConnection(
		final InetSocketAddress serverAddress,
		final MessageSerializer<REQ, RESP> serializer,
		final Channel channel) {

	this.serverAddress = Preconditions.checkNotNull(serverAddress);
	this.channel = Preconditions.checkNotNull(channel);

	// Add the client handler with the callback
	channel.pipeline().addLast(
			getClientName() + " Handler",
			new ClientHandler<>(clientName, serializer, this)
	);

	stats.reportActiveConnection();
}
 

/**
 * Creates an established connection with the given channel.
 *
 * @param serverAddress Address of the server connected to
 * @param channel The actual TCP channel
 */
EstablishedConnection(
		final InetSocketAddress serverAddress,
		final MessageSerializer<REQ, RESP> serializer,
		final Channel channel) {

	this.serverAddress = Preconditions.checkNotNull(serverAddress);
	this.channel = Preconditions.checkNotNull(channel);

	// Add the client handler with the callback
	channel.pipeline().addLast(
			getClientName() + " Handler",
			new ClientHandler<>(clientName, serializer, this)
	);

	stats.reportActiveConnection();
}
 

/**
 * Tests that the channel is closed if an Exception reaches the channel handler.
 */
@Test
public void testCloseChannelOnExceptionCaught() throws Exception {
	KvStateRegistry registry = new KvStateRegistry();
	AtomicKvStateRequestStats stats = new AtomicKvStateRequestStats();

	MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	KvStateServerHandler handler = new KvStateServerHandler(testServer, registry, serializer, stats);
	EmbeddedChannel channel = new EmbeddedChannel(handler);

	channel.pipeline().fireExceptionCaught(new RuntimeException("Expected test Exception"));

	ByteBuf buf = (ByteBuf) readInboundBlocking(channel);
	buf.skipBytes(4); // skip frame length

	// Verify the response
	assertEquals(MessageType.SERVER_FAILURE, MessageSerializer.deserializeHeader(buf));
	Throwable response = MessageSerializer.deserializeServerFailure(buf);

	assertTrue(response.getMessage().contains("Expected test Exception"));

	channel.closeFuture().await(READ_TIMEOUT_MILLIS);
	assertFalse(channel.isActive());
}
 

/**
 * Create the Queryable State Client.
 * @param remoteAddress the {@link InetAddress address} of the {@code Client Proxy} to connect to.
 * @param remotePort the port of the proxy to connect to.
 */
public QueryableStateClient(final InetAddress remoteAddress, final int remotePort) {
	Preconditions.checkArgument(remotePort >= 0 && remotePort <= 65536,
			"Remote Port " + remotePort + " is out of valid port range (0-65536).");

	this.remoteAddress = new InetSocketAddress(remoteAddress, remotePort);

	final MessageSerializer<KvStateRequest, KvStateResponse> messageSerializer =
			new MessageSerializer<>(
					new KvStateRequest.KvStateRequestDeserializer(),
					new KvStateResponse.KvStateResponseDeserializer());

	this.client = new Client<>(
			"Queryable State Client",
			1,
			messageSerializer,
			new DisabledKvStateRequestStats());
}
 

/**
 * Tests that the channel is closed if an Exception reaches the channel handler.
 */
@Test
public void testCloseChannelOnExceptionCaught() throws Exception {
	KvStateRegistry registry = new KvStateRegistry();
	AtomicKvStateRequestStats stats = new AtomicKvStateRequestStats();

	MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	KvStateServerHandler handler = new KvStateServerHandler(testServer, registry, serializer, stats);
	EmbeddedChannel channel = new EmbeddedChannel(handler);

	channel.pipeline().fireExceptionCaught(new RuntimeException("Expected test Exception"));

	ByteBuf buf = (ByteBuf) readInboundBlocking(channel);
	buf.skipBytes(4); // skip frame length

	// Verify the response
	assertEquals(MessageType.SERVER_FAILURE, MessageSerializer.deserializeHeader(buf));
	Throwable response = MessageSerializer.deserializeServerFailure(buf);

	assertTrue(response.getMessage().contains("Expected test Exception"));

	channel.closeFuture().await(READ_TIMEOUT_MILLIS);
	assertFalse(channel.isActive());
}
 

/**
 * Tests request failure serialization.
 */
@Test
public void testKvStateRequestFailureSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 1111222L;
	IllegalStateException cause = new IllegalStateException("Expected test");

	ByteBuf buf = MessageSerializer.serializeRequestFailure(alloc, requestId, cause);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST_FAILURE, MessageSerializer.deserializeHeader(buf));
	RequestFailure requestFailure = MessageSerializer.deserializeRequestFailure(buf);
	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(requestId, requestFailure.getRequestId());
	assertEquals(cause.getClass(), requestFailure.getCause().getClass());
	assertEquals(cause.getMessage(), requestFailure.getCause().getMessage());
}
 

/**
 * Tests response serialization with zero-length serialized result.
 */
@Test
public void testResponseSerializationWithZeroLengthSerializedResult() throws Exception {
	byte[] serializedResult = new byte[0];

	final KvStateResponse response = new KvStateResponse(serializedResult);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeResponse(alloc, 72727278L, response);

	int frameLength = buf.readInt();

	assertEquals(MessageType.REQUEST_RESULT, MessageSerializer.deserializeHeader(buf));
	assertEquals(72727278L, MessageSerializer.getRequestId(buf));
	KvStateResponse responseDeser = serializer.deserializeResponse(buf);
	assertEquals(buf.readerIndex(), frameLength + 4);

	assertArrayEquals(serializedResult, responseDeser.getContent());
}
 

/**
 * Tests response serialization.
 */
@Test
public void testResponseSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 72727278L;
	byte[] serializedResult = randomByteArray(1024);

	final KvStateResponse response = new KvStateResponse(serializedResult);
	final MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	ByteBuf buf = MessageSerializer.serializeResponse(alloc, requestId, response);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST_RESULT, MessageSerializer.deserializeHeader(buf));
	assertEquals(requestId, MessageSerializer.getRequestId(buf));
	KvStateResponse responseDeser = serializer.deserializeResponse(buf);

	assertEquals(buf.readerIndex(), frameLength + 4);

	assertArrayEquals(serializedResult, responseDeser.getContent());
}
 

/**
 * Tests request failure serialization.
 */
@Test
public void testKvStateRequestFailureSerialization() throws Exception {
	long requestId = Integer.MAX_VALUE + 1111222L;
	IllegalStateException cause = new IllegalStateException("Expected test");

	ByteBuf buf = MessageSerializer.serializeRequestFailure(alloc, requestId, cause);

	int frameLength = buf.readInt();
	assertEquals(MessageType.REQUEST_FAILURE, MessageSerializer.deserializeHeader(buf));
	RequestFailure requestFailure = MessageSerializer.deserializeRequestFailure(buf);
	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(requestId, requestFailure.getRequestId());
	assertEquals(cause.getClass(), requestFailure.getCause().getClass());
	assertEquals(cause.getMessage(), requestFailure.getCause().getMessage());
}
 

/**
 * Creates a pending connection to the given server.
 *
 * @param serverAddress Address of the server to connect to.
 */
private PendingConnection(
		final InetSocketAddress serverAddress,
		final MessageSerializer<REQ, RESP> serializer) {
	this.serverAddress = serverAddress;
	this.serializer = serializer;
}
 

/**
 * Tests that the channel is closed if an Exception reaches the channel handler.
 */
@Test
public void testCloseChannelOnExceptionCaught() throws Exception {
	KvStateRegistry registry = new KvStateRegistry();
	AtomicKvStateRequestStats stats = new AtomicKvStateRequestStats();

	MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	KvStateServerHandler handler = new KvStateServerHandler(testServer, registry, serializer, stats);
	EmbeddedChannel channel = new EmbeddedChannel(handler);

	channel.pipeline().fireExceptionCaught(new RuntimeException("Expected test Exception"));

	ByteBuf buf = (ByteBuf) readInboundBlocking(channel);
	buf.skipBytes(4); // skip frame length

	// Verify the response
	assertEquals(MessageType.SERVER_FAILURE, MessageSerializer.deserializeHeader(buf));
	Throwable response = MessageSerializer.deserializeServerFailure(buf);
	buf.release();

	assertTrue(response.getMessage().contains("Expected test Exception"));

	channel.closeFuture().await(READ_TIMEOUT_MILLIS);
	assertFalse(channel.isActive());
}
 

/**
 * Create the handler used by the {@link KvStateClientProxyImpl}.
 *
 * @param proxy the {@link KvStateClientProxyImpl proxy} using the handler.
 * @param queryExecutorThreads the number of threads used to process incoming requests.
 * @param serializer the {@link MessageSerializer} used to (de-) serialize the different messages.
 * @param stats server statistics collector.
 */
public KvStateClientProxyHandler(
		final KvStateClientProxyImpl proxy,
		final int queryExecutorThreads,
		final MessageSerializer<KvStateRequest, KvStateResponse> serializer,
		final KvStateRequestStats stats) {

	super(proxy, serializer, stats);
	this.proxy = Preconditions.checkNotNull(proxy);
	this.kvStateClient = createInternalClient(queryExecutorThreads);
}
 

/**
 * Tests server failure serialization.
 */
@Test
public void testServerFailureSerialization() throws Exception {
	IllegalStateException cause = new IllegalStateException("Expected test");

	ByteBuf buf = MessageSerializer.serializeServerFailure(alloc, cause);

	int frameLength = buf.readInt();
	assertEquals(MessageType.SERVER_FAILURE, MessageSerializer.deserializeHeader(buf));
	Throwable request = MessageSerializer.deserializeServerFailure(buf);
	assertEquals(buf.readerIndex(), frameLength + 4);

	assertEquals(cause.getClass(), request.getClass());
	assertEquals(cause.getMessage(), request.getMessage());
}
 

/**
 * Tests that incoming buffer instances are recycled.
 */
@Test
public void testIncomingBufferIsRecycled() throws Exception {
	KvStateRegistry registry = new KvStateRegistry();
	AtomicKvStateRequestStats stats = new AtomicKvStateRequestStats();

	MessageSerializer<KvStateInternalRequest, KvStateResponse> serializer =
			new MessageSerializer<>(new KvStateInternalRequest.KvStateInternalRequestDeserializer(), new KvStateResponse.KvStateResponseDeserializer());

	KvStateServerHandler handler = new KvStateServerHandler(testServer, registry, serializer, stats);
	EmbeddedChannel channel = new EmbeddedChannel(getFrameDecoder(), handler);

	KvStateInternalRequest request = new KvStateInternalRequest(new KvStateID(), new byte[0]);
	ByteBuf serRequest = MessageSerializer.serializeRequest(channel.alloc(), 282872L, request);

	assertEquals(1L, serRequest.refCnt());

	// Write regular request
	channel.writeInbound(serRequest);
	assertEquals("Buffer not recycled", 0L, serRequest.refCnt());

	// Write unexpected msg
	ByteBuf unexpected = channel.alloc().buffer(8);
	unexpected.writeInt(4);
	unexpected.writeInt(4);

	assertEquals(1L, unexpected.refCnt());

	channel.writeInbound(unexpected);
	assertEquals("Buffer not recycled", 0L, unexpected.refCnt());
}