ZOOKEEPER-1382. Zookeeper server holds onto dead/expired session ids in the watch data structures

  (Germán Blanco and Michael Morello via camille)

git-svn-id: https://svn.apache.org/repos/asf/zookeeper/branches/branch-3.4@1550220 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -179,6 +179,9 @@ BUGFIXES:
   (Raul Gutierrez Segales via michim)
 
   ZOOKEEPER-1834. Catch IOException in FileTxnLog (fpj via michim)
+  
+  ZOOKEEPER-1382. Zookeeper server holds onto dead/expired session ids in the watch data structures
+  (Germán Blanco and Michael Morello via camille)
 
 IMPROVEMENTS:
 

src/java/main/org/apache/zookeeper/server/NIOServerCnxn.java

@@ -204,9 +204,19 @@ public class NIOServerCnxn extends ServerCnxn {
         }
     }
 
+    /**
+     * Only used in order to allow testing
+     */
+    protected boolean isSocketOpen() {
+        return sock.isOpen();
+    }
+
+    /**
+     * Handles read/write IO on connection.
+     */
     void doIO(SelectionKey k) throws InterruptedException {
         try {
-            if (sock.isOpen() == false) {
+            if (isSocketOpen() == false) {
                 LOG.warn("trying to do i/o on a null socket for session:0x"
                          + Long.toHexString(sessionId));
 

src/java/main/org/apache/zookeeper/server/ZooKeeperServer.java

@@ -619,9 +619,9 @@ public class ZooKeeperServer implements SessionExpirer, ServerStats.Provider {
                         + " with negotiated timeout " + cnxn.getSessionTimeout()
                         + " for client "
                         + cnxn.getRemoteSocketAddress());
+                cnxn.enableRecv();
             }
                 
-            cnxn.enableRecv();
         } catch (Exception e) {
             LOG.warn("Exception while establishing session, closing", e);
             cnxn.close();

src/java/test/org/apache/zookeeper/MockPacket.java

+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.zookeeper;
+
+import org.apache.zookeeper.proto.RequestHeader;
+import org.apache.zookeeper.proto.ReplyHeader;
+import org.apache.jute.Record;
+import org.apache.zookeeper.ZooKeeper.WatchRegistration;
+import java.nio.ByteBuffer;
+
+public class MockPacket extends ClientCnxn.Packet {
+
+    public MockPacket(RequestHeader requestHeader, ReplyHeader replyHeader,
+               Record request, Record response,
+               WatchRegistration watchRegistration) {
+        super(requestHeader, replyHeader, request, response, watchRegistration);
+    }
+
+    public MockPacket(RequestHeader requestHeader, ReplyHeader replyHeader,
+               Record request, Record response,
+               WatchRegistration watchRegistration, boolean readOnly) {
+        super(requestHeader, replyHeader, request, response, watchRegistration, readOnly);
+    }
+
+    public ByteBuffer createAndReturnBB() {
+        createBB();
+        return this.bb;
+    }
+
+}

src/java/test/org/apache/zookeeper/server/MockNIOServerCnxn.java

+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.zookeeper.server;
+
+import java.nio.channels.SelectionKey;
+import java.nio.channels.SocketChannel;
+import java.io.IOException;
+
+public class MockNIOServerCnxn extends NIOServerCnxn {
+
+    public MockNIOServerCnxn(ZooKeeperServer zk, SocketChannel sock,
+                         SelectionKey sk, NIOServerCnxnFactory factory)
+                         throws IOException {
+        super(zk, sock, sk, factory);
+    }
+
+    /**
+     * Handles read/write IO on connection.
+     */
+    public void doIO(SelectionKey k) throws InterruptedException {
+        super.doIO(k);
+    }
+
+     @Override
+     protected boolean isSocketOpen() {
+         return true;
+     }
+
+}

src/java/test/org/apache/zookeeper/server/quorum/WatchLeakTest.java

+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to you 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 org.apache.zookeeper.server.quorum;
+
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.junit.Assert.*;
+
+import java.io.BufferedOutputStream;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.nio.ByteBuffer;
+import java.nio.channels.SelectableChannel;
+import java.nio.channels.SelectionKey;
+import java.nio.channels.Selector;
+import java.nio.channels.SocketChannel;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+
+import org.apache.jute.InputArchive;
+import org.apache.jute.OutputArchive;
+import org.apache.zookeeper.MockPacket;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.proto.ConnectRequest;
+import org.apache.zookeeper.proto.ReplyHeader;
+import org.apache.zookeeper.proto.RequestHeader;
+import org.apache.zookeeper.proto.SetWatches;
+import org.apache.zookeeper.server.MockNIOServerCnxn;
+import org.apache.zookeeper.server.NIOServerCnxnFactory;
+import org.apache.zookeeper.server.ZKDatabase;
+import org.apache.zookeeper.server.ZooTrace;
+import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
+import org.junit.Test;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Demonstrate ZOOKEEPER-1382 : Watches leak on expired session
+ */
+public class WatchLeakTest {
+
+    protected static final Logger LOG = LoggerFactory
+            .getLogger(WatchLeakTest.class);
+
+    final long SESSION_ID = 0xBABEL;
+
+    /**
+     * ZOOKEEPR-1382 test class
+     */
+    @Test
+    public void testWatchesWithClientSessionTimeout() throws Exception {
+
+        NIOServerCnxnFactory serverCnxnFactory = new NIOServerCnxnFactory();
+
+        ZKDatabase database = new ZKDatabase(null);
+        database.setlastProcessedZxid(2L);
+        QuorumPeer quorumPeer = mock(QuorumPeer.class);
+        FileTxnSnapLog logfactory = mock(FileTxnSnapLog.class);
+        // Directories are not used but we need it to avoid NPE
+        when(logfactory.getDataDir()).thenReturn(new File("/tmp"));
+        when(logfactory.getSnapDir()).thenReturn(new File("/tmp"));
+        FollowerZooKeeperServer fzks = null;
+        try {
+            fzks = new FollowerZooKeeperServer(logfactory, quorumPeer, null,
+                    database);
+            fzks.startup();
+            fzks.setServerCnxnFactory(serverCnxnFactory);
+            quorumPeer.follower = new MyFollower(quorumPeer, fzks);
+            final SelectionKey sk = new FakeSK();
+            // Simulate a socket channel between a client and a follower
+            final SocketChannel socketChannel = createClientSocketChannel();
+            // Create the NIOServerCnxn that will handle the client requests
+            final MockNIOServerCnxn nioCnxn = new MockNIOServerCnxn(fzks,
+                    socketChannel, sk, serverCnxnFactory);
+            // Send the connection request as a client do
+            nioCnxn.doIO(sk);
+            // Send the invalid session packet to the follower
+            QuorumPacket qp = createInvalidSessionPacket();
+            quorumPeer.follower.processPacket(qp);
+            // OK, now the follower knows that the session is invalid, let's try
+            // to
+            // send it the watches
+            nioCnxn.doIO(sk);
+            // wait for the the request processor to do his job
+            Thread.sleep(1000L);
+            // Session has not been re-validated !
+            // If session has not been validated, there must be NO watches
+            int watchCount = database.getDataTree().getWatchCount();
+            LOG.info("watches = " + watchCount);
+            assertEquals(0, watchCount);
+        } finally {
+            if (fzks != null) {
+                fzks.shutdown();
+            }
+        }
+    }
+
+    /**
+     * A follower with no real leader connection
+     */
+    public static class MyFollower extends Follower {
+        /**
+         * Create a follower with a mocked leader connection
+         * 
+         * @param self
+         * @param zk
+         */
+        MyFollower(QuorumPeer self, FollowerZooKeeperServer zk) {
+            super(self, zk);
+            leaderOs = mock(OutputArchive.class);
+            leaderIs = mock(InputArchive.class);
+            bufferedOutput = mock(BufferedOutputStream.class);
+        }
+    }
+
+    /**
+     * Simulate the behavior of a real selection key
+     */
+    private static class FakeSK extends SelectionKey {
+
+        @Override
+        public SelectableChannel channel() {
+            return null;
+        }
+
+        @Override
+        public Selector selector() {
+            return mock(Selector.class);
+        }
+
+        @Override
+        public boolean isValid() {
+            return true;
+        }
+
+        @Override
+        public void cancel() {
+        }
+
+        @Override
+        public int interestOps() {
+            return ops;
+        }
+
+        private int ops = OP_WRITE + OP_READ;
+
+        @Override
+        public SelectionKey interestOps(int ops) {
+            this.ops = ops;
+            return this;
+        }
+
+        @Override
+        public int readyOps() {
+            return ops;
+        }
+
+    }
+
+    /**
+     * Create a watches message with a single watch on /
+     * 
+     * @return
+     */
+    private ByteBuffer createWatchesMessage() {
+        List<String> dataWatches = new ArrayList<String>(1);
+        dataWatches.add("/");
+        List<String> existWatches = Collections.emptyList();
+        List<String> childWatches = Collections.emptyList();
+        SetWatches sw = new SetWatches(1L, dataWatches, existWatches,
+                childWatches);
+        RequestHeader h = new RequestHeader();
+        h.setType(ZooDefs.OpCode.setWatches);
+        h.setXid(-8);
+        MockPacket p = new MockPacket(h, new ReplyHeader(), sw, null, null);
+        return p.createAndReturnBB();
+    }
+
+    /**
+     * This is the secret that we use to generate passwords, for the moment it
+     * is more of a sanity check.
+     */
+    static final private long superSecret = 0XB3415C00L;
+
+    /**
+     * Create a connection request
+     * 
+     * @return
+     */
+    private ByteBuffer createConnRequest() {
+        Random r = new Random(SESSION_ID ^ superSecret);
+        byte p[] = new byte[16];
+        r.nextBytes(p);
+        ConnectRequest conReq = new ConnectRequest(0, 1L, 30000, SESSION_ID, p);
+        MockPacket packet = new MockPacket(null, null, conReq, null, null, false);
+        return packet.createAndReturnBB();
+    }
+
+    /**
+     * Mock a client channel with a connection request and a watches message
+     * inside.
+     * 
+     * @return a socket channel
+     * @throws IOException
+     */
+    private SocketChannel createClientSocketChannel() throws IOException {
+
+        SocketChannel socketChannel = mock(SocketChannel.class);
+        Socket socket = mock(Socket.class);
+        InetSocketAddress socketAddress = new InetSocketAddress(1234);
+        when(socket.getRemoteSocketAddress()).thenReturn(socketAddress);
+        when(socketChannel.socket()).thenReturn(socket);
+
+        // Send watches packet to server connection
+        final ByteBuffer connRequest = createConnRequest();
+        final ByteBuffer watchesMessage = createWatchesMessage();
+        final ByteBuffer request = ByteBuffer.allocate(connRequest.limit()
+                + watchesMessage.limit());
+        request.put(connRequest);
+        request.put(watchesMessage);
+
+        Answer<Integer> answer = new Answer<Integer>() {
+            int i = 0;
+
+            @Override
+            public Integer answer(InvocationOnMock invocation) throws Throwable {
+                Object[] args = invocation.getArguments();
+                ByteBuffer bb = (ByteBuffer) args[0];
+                for (int k = 0; k < bb.limit(); k++) {
+                    bb.put(request.get(i));
+                    i = i + 1;
+                }
+                return bb.limit();
+            }
+        };
+        when(socketChannel.read(any(ByteBuffer.class))).thenAnswer(answer);
+        return socketChannel;
+    }
+
+    /**
+     * Forge an invalid session packet as a LEADER do
+     * 
+     * @throws Exception
+     */
+    private QuorumPacket createInvalidSessionPacket() throws Exception {
+        QuorumPacket qp = createValidateSessionQuorumPacket();
+        ByteArrayInputStream bis = new ByteArrayInputStream(qp.getData());
+        DataInputStream dis = new DataInputStream(bis);
+        long id = dis.readLong();
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        DataOutputStream dos = new DataOutputStream(bos);
+        dos.writeLong(id);
+        // false means that the session has expired
+        dos.writeBoolean(false);
+        qp.setData(bos.toByteArray());
+        return qp;
+    }
+
+    /**
+     * Forge an validate session packet as a LEARNER do
+     * 
+     * @return
+     * @throws Exception
+     */
+    private QuorumPacket createValidateSessionQuorumPacket() throws Exception {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        DataOutputStream dos = new DataOutputStream(baos);
+        dos.writeLong(SESSION_ID);
+        dos.writeInt(3000);
+        dos.close();
+        QuorumPacket qp = new QuorumPacket(Leader.REVALIDATE, -1,
+                baos.toByteArray(), null);
+        if (LOG.isTraceEnabled()) {
+            ZooTrace.logTraceMessage(LOG, ZooTrace.SESSION_TRACE_MASK,
+                    "To validate session 0x" + Long.toHexString(2L));
+        }
+        return qp;
+    }
+
+}
\ No newline at end of file