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Original file line number Diff line number Diff line change
Expand Up @@ -47,9 +47,9 @@ public class ReadOnlyRequestProcessor extends ZooKeeperCriticalThread implements

private final RequestProcessor nextProcessor;

private final ZooKeeperServer zks;
private final ReadOnlyZooKeeperServer zks;

public ReadOnlyRequestProcessor(ZooKeeperServer zks, RequestProcessor nextProcessor) {
public ReadOnlyRequestProcessor(ReadOnlyZooKeeperServer zks, RequestProcessor nextProcessor) {
super("ReadOnlyRequestProcessor:" + zks.getServerId(), zks.getZooKeeperServerListener());
this.zks = zks;
this.nextProcessor = nextProcessor;
Expand All @@ -72,6 +72,11 @@ public void run() {
break;
}

// proceed to the next processor
if (nextProcessor != null) {
nextProcessor.processRequest(request);
}

// filter read requests
switch (request.type) {
case OpCode.sync:
Expand All @@ -86,21 +91,10 @@ public void run() {
case OpCode.setACL:
case OpCode.multi:
case OpCode.check:
ReplyHeader hdr = new ReplyHeader(
request.cxid,
zks.getZKDatabase().getDataTreeLastProcessedZxid(),
Code.NOTREADONLY.intValue());
try {
request.cnxn.sendResponse(hdr, null, null);
} catch (IOException e) {
LOG.error("IO exception while sending response", e);
}
continue;
}

// proceed to the next processor
if (nextProcessor != null) {
nextProcessor.processRequest(request);
zks.commitErrorRequest(request);
break;
default:
/* pass for read */
}
}
} catch (Exception e) {
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -21,15 +21,22 @@
import java.io.PrintWriter;
import java.util.Objects;
import java.util.stream.Collectors;
import org.apache.zookeeper.KeeperException.Code;
import org.apache.zookeeper.ZooDefs.OpCode;
import org.apache.zookeeper.common.Time;
import org.apache.zookeeper.jmx.MBeanRegistry;
import org.apache.zookeeper.server.DataTreeBean;
import org.apache.zookeeper.server.FinalRequestProcessor;
import org.apache.zookeeper.server.PrepRequestProcessor;
import org.apache.zookeeper.server.Request;
import org.apache.zookeeper.server.RequestProcessor;
import org.apache.zookeeper.server.ZKDatabase;
import org.apache.zookeeper.server.ZooKeeperServer;
import org.apache.zookeeper.server.ZooKeeperServerBean;
import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
import org.apache.zookeeper.server.DataTreeBean;
import org.apache.zookeeper.txn.ErrorTxn;
import org.apache.zookeeper.txn.TxnHeader;

/**
* A ZooKeeperServer which comes into play when peer is partitioned from the
Expand All @@ -43,6 +50,7 @@ public class ReadOnlyZooKeeperServer extends ZooKeeperServer {

protected final QuorumPeer self;
private volatile boolean shutdown = false;
private CommitProcessor commitProcessor;

ReadOnlyZooKeeperServer(FileTxnSnapLog logFactory, QuorumPeer self, ZKDatabase zkDb) {
super(
Expand All @@ -60,9 +68,10 @@ public class ReadOnlyZooKeeperServer extends ZooKeeperServer {
@Override
protected void setupRequestProcessors() {
RequestProcessor finalProcessor = new FinalRequestProcessor(this);
RequestProcessor prepProcessor = new PrepRequestProcessor(this, finalProcessor);
((PrepRequestProcessor) prepProcessor).start();
firstProcessor = new ReadOnlyRequestProcessor(this, prepProcessor);
commitProcessor = new CommitProcessor(finalProcessor,
Long.toString(getServerId()), true, getZooKeeperServerListener());
commitProcessor.start();
firstProcessor = new ReadOnlyRequestProcessor(this, commitProcessor);
((ReadOnlyRequestProcessor) firstProcessor).start();
}

Expand Down Expand Up @@ -187,4 +196,36 @@ protected void setState(State state) {
this.state = state;
}

/**
* Didn't throw here if we're creating or closing global session,
* will leave it to the RequstOnlyRequestProcessor to reject it
* like other update ops.
*/
@Override
protected void setLocalSessionFlag(Request si) {
switch (si.type) {
case OpCode.createSession:
if (self.areLocalSessionsEnabled()) {
si.setLocalSession(true);
}
break;
case OpCode.closeSession:
if (((UpgradeableSessionTracker) sessionTracker).isLocalSession(si.sessionId)) {
si.setLocalSession(true);
} else {
LOG.warn("Submitting global closeSession request for session " +
"0x{} in ReadOnly mode", Long.toHexString(si.sessionId));
}
break;
default:
break;
}
}

public void commitErrorRequest(final Request request) {
request.setHdr(new TxnHeader(request.sessionId, request.cxid, 0,
Time.currentWallTime(), OpCode.error));
request.setTxn(new ErrorTxn(Code.NOTREADONLY.intValue()));
commitProcessor.commit(request);
}
}
Original file line number Diff line number Diff line change
@@ -0,0 +1,253 @@
/**
* 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.io.File;
import java.io.IOException;
import java.util.Vector;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.zookeeper.PortAssignment;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.ZooKeeper.States;
import org.apache.zookeeper.AsyncCallback.DataCallback;
import org.apache.zookeeper.AsyncCallback.StatCallback;
import org.apache.zookeeper.common.X509Exception.SSLContextException;
import org.apache.zookeeper.data.Stat;
import org.apache.zookeeper.server.quorum.QuorumPeerTestBase;
import org.apache.zookeeper.test.ClientBase;
import org.apache.zookeeper.test.QuorumBase;

import org.junit.Assert;
import org.junit.Test;
import org.slf4j.LoggerFactory;

import static org.apache.zookeeper.client.FourLetterWordMain.send4LetterWord;

public class ReadOnlyZooKeeperServerTest extends QuorumPeerTestBase {
private static final org.slf4j.Logger LOG = LoggerFactory
.getLogger(ReadOnlyZooKeeperServerTest.class);

private static int CONNECTION_TIMEOUT = QuorumBase.CONNECTION_TIMEOUT;
public static int WAIT_TIMEOUT = 60000;

Vector<MainThread> servers = new Vector<MainThread>();
Vector<ServerConfig> configs = new Vector<ServerConfig>();

int[] SERVERS = { 0, 1, 2, 3 };
int[] PARTICIPANTS = { 0, 1, 2 };
int[] OBSERVER = { 3 };

int OBSERVER_ID = 3;
int OBSERVER_PORT;

/**
* Make sure the response is returned in order in RO mode.
*/
@Test
public void testResponseOrder() throws Exception {
System.setProperty("readonlymode.enabled", "true");

ClientBase.setupTestEnv();
setupServers(true);

startup(OBSERVER, false);
waitForISRO("ro", OBSERVER_PORT, 60);

final ZooKeeper rozk = new ZooKeeper("127.0.0.1:" +
OBSERVER_PORT, ClientBase.CONNECTION_TIMEOUT, this, true);
waitForOne(rozk, States.CONNECTEDREADONLY);

final int requestCount = 1000;
final AtomicInteger successGetResponseCount = new AtomicInteger();
final CountDownLatch getResponseLatch = new CountDownLatch(requestCount);
Thread getDataThread = new Thread(new Runnable() {
@Override
public void run() {
int requestIssued = 0;
while (requestIssued++ < requestCount) {
rozk.getData("/", null, new DataCallback() {
@Override
public void processResult(int rc, String path,
Object ctx, byte data[], Stat stat) {
if (rc == 0) {
successGetResponseCount.incrementAndGet();
}
getResponseLatch.countDown();
}
}, null);
}
}
});
final CountDownLatch setResponseLatch = new CountDownLatch(requestCount);
Thread setDataThread = new Thread(new Runnable() {
@Override
public void run() {
int requestIssued = 0;
while (requestIssued++ < requestCount) {
rozk.setData("/test", new byte[0], -1, new StatCallback() {
@Override
public void processResult(int rc, String path,
Object ctx, Stat stat) {
setResponseLatch.countDown();
}
}, null);
}
}
});

getDataThread.start();
setDataThread.start();

Assert.assertTrue(getResponseLatch.await(2, TimeUnit.SECONDS));
Assert.assertTrue(setResponseLatch.await(2, TimeUnit.SECONDS));
Assert.assertEquals(requestCount, successGetResponseCount.get());

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How would these three Assert verify the order of the responses?

rozk.close();
shutdown(OBSERVER);
}

/**
* Setup servers (3 participants + 1 observer)
*/
void setupServers(boolean localSessionsEnabled) throws IOException {
configs.clear();
servers.clear();
Vector<ServerConfig> ensembleConfigs = new Vector<ServerConfig>();

for (int i = 0; i < 4; i++) {
ServerConfig config = new ServerConfig(i);
configs.add(config);
if (i != OBSERVER_ID) {
ensembleConfigs.add(config);
}
}

StringBuilder hostList = new StringBuilder();
for (ServerConfig config : configs) {
hostList.append("server." + config.id + "=127.0.0.1:"
+ config.qpPort + ":" + config.lePort);
if (config.id == OBSERVER_ID) {
hostList.append(":observer");
}
hostList.append("\n");
}

String quorumCfgSection = hostList.toString();

for (ServerConfig config : configs) {
MainThread server = new MainThread(config.id, config.clientPort,
quorumCfgSection, "localSessionsEnabled=" +
Boolean.toString(localSessionsEnabled) + "\n" +
"localSessionsUpgradingEnabled=" +
Boolean.toString(localSessionsEnabled) + "\n");
if (config.id != OBSERVER_ID) {
config.confFile = server.getConfFile();
}
servers.add(server);
}

OBSERVER_PORT = configs.get(OBSERVER_ID).clientPort;
}

void startup(int[] serverIds) {
startup(serverIds, true);
}

void startup(int[] serverIds, boolean verify) {
for (int i : serverIds) {
servers.get(i).start();
}
if (verify) {
for (int i : serverIds) {
if (!ClientBase.waitForServerUp("127.0.0.1:"
+ configs.get(i).clientPort, WAIT_TIMEOUT)) {
throw new RuntimeException("Server " + i
+ " did not start up");
}
}
}
}

void shutdown(int[] serverIds) throws InterruptedException {
for (int i : serverIds) {
servers.get(i).shutdown();
}
for (int i : serverIds) {
if (!ClientBase.waitForServerDown("127.0.0.1:"
+ configs.get(i).clientPort, WAIT_TIMEOUT)) {
throw new RuntimeException("Server " + i + " did not shutdown");
}
}
}

/**
* Wait for server rw/ro state change
*
* @param mode
* "ro" or "rw"
* @param port
* @param timeout
* @return
* @throws InterruptedException
* @throws IOException
*/
boolean waitForISRO(String mode, int port, int timeout)
throws InterruptedException, IOException, SSLContextException {
for (int i = 0; i < timeout; ++i) {
Thread.sleep(1000);
String resp = send4LetterWord("127.0.0.1", port, "isro");
LOG.info("ISRO response for [" + port + "] ==" + resp + "==" + mode);
if (resp.startsWith(mode)) {
return true;
}
}
return false;
}

/**
* Store server configuration information. Backup ports are used to simulate
* partitioning between observer and participants.
*/
class ServerConfig {

int qpPort;
int lePort;
int clientPort;
int qpBackupPort;
int leBackupPort;

int id;
File confFile;

ServerConfig(int id) {
qpPort = PortAssignment.unique();
lePort = PortAssignment.unique();
clientPort = PortAssignment.unique();
this.id = id;
if (id != OBSERVER_ID) {
qpBackupPort = PortAssignment.unique();
leBackupPort = PortAssignment.unique();
}
}
}

}