[Bug-3140]fix the deadlock between start and stop of ZKServer (#3141) (753ed58f) · Commits · SUMMER2020 / students / proj-2002251

dolphinscheduler-service/src/main/java/org/apache/dolphinscheduler/service/zk/ZKServer.java

+71 −48

Original line number	Diff line number	Diff line
		@@ -16,6 +16,7 @@
		*/
		package org.apache.dolphinscheduler.service.zk;

		import org.apache.dolphinscheduler.common.utils.StringUtils;
		import org.apache.zookeeper.server.ZooKeeperServer;
		import org.apache.zookeeper.server.ZooKeeperServerMain;
		import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
		@@ -34,44 +35,62 @@ import java.util.concurrent.atomic.AtomicBoolean;
		public class ZKServer {
		private static final Logger logger = LoggerFactory.getLogger(ZKServer.class);

		private static volatile PublicZooKeeperServerMain zkServer = null;

		public static final int DEFAULT_ZK_TEST_PORT = 2181;

		private static String dataDir = null;
		private final AtomicBoolean isStarted = new AtomicBoolean(false);

		private PublicZooKeeperServerMain zooKeeperServerMain = null;

		private int port;

		private static final AtomicBoolean isStarted = new AtomicBoolean(false);
		private String dataDir = null;

		private String prefix;

		public static void main(String[] args) {
		if(!isStarted()){
		ZKServer.start();
		ZKServer zkServer;
		if (args.length == 0) {
		zkServer = new ZKServer();
		} else if (args.length == 1){
		zkServer = new ZKServer(Integer.valueOf(args[0]), "");
		} else {
		zkServer = new ZKServer(Integer.valueOf(args[0]), args[1]);
		}
		zkServer.registerHook();
		zkServer.start();
		}

		public ZKServer() {
		this(DEFAULT_ZK_TEST_PORT, "");
		}

		public ZKServer(int port, String prefix) {
		this.port = port;
		if (prefix != null && prefix.contains("/")) {
		throw new IllegalArgumentException("The prefix of path may not have '/'");
		}
		this.prefix = (prefix == null ? null : prefix.trim());
		}

		private void registerHook() {
		/**
		* register hooks, which are called before the process exits
		*/
		Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
		@Override
		public void run() {
		stop();
		}
		}));
		}else{
		logger.info("zk server aleady started");
		}
		Runtime.getRuntime().addShutdownHook(new Thread(this::stop));
		}

		/**
		* start service
		*/
		public static void start() {
		public void start() {
		try {
		startLocalZkServer(DEFAULT_ZK_TEST_PORT);
		startLocalZkServer(port);
		} catch (Exception e) {
		logger.error("Failed to start ZK: " + e);
		logger.error("Failed to start ZK ", e);
		}
		}

		public static boolean isStarted(){
		public boolean isStarted(){
		return isStarted.get();
		}

		@@ -94,8 +113,12 @@ public class ZKServer {
		*
		* @param port The port to listen on
		*/
		public static void startLocalZkServer(final int port) {
		String zkDataDir = System.getProperty("user.dir") +"/zookeeper_data";
		public void startLocalZkServer(final int port) {
		String zkDataDir = System.getProperty("user.dir") + (StringUtils.isEmpty(prefix) ? StringUtils.EMPTY : ("/" + prefix)) + "/zookeeper_data";
		File file = new File(zkDataDir);
		if (file.exists()) {
		logger.warn("The path of zk server exists");
		}
		logger.info("zk server starting, data dir path:{}" , zkDataDir);
		startLocalZkServer(port, zkDataDir, ZooKeeperServer.DEFAULT_TICK_TIME,"60");
		}
		@@ -108,11 +131,9 @@ public class ZKServer {
		* @param tickTime zk tick time
		* @param maxClientCnxns zk max client connections
		*/
		private static synchronized void startLocalZkServer(final int port, final String dataDirPath,final int tickTime,String maxClientCnxns) {
		if (zkServer != null) {
		throw new RuntimeException("Zookeeper server is already started!");
		}
		zkServer = new PublicZooKeeperServerMain();
		private void startLocalZkServer(final int port, final String dataDirPath,final int tickTime,String maxClientCnxns) {
		if (isStarted.compareAndSet(false, true)) {
		zooKeeperServerMain = new PublicZooKeeperServerMain();
		logger.info("Zookeeper data path : {} ", dataDirPath);
		dataDir = dataDirPath;
		final String[] args = new String[]{Integer.toString(port), dataDirPath, Integer.toString(tickTime), maxClientCnxns};
		@@ -121,18 +142,18 @@ public class ZKServer {
		logger.info("Zookeeper server started ");
		isStarted.compareAndSet(false, true);

		zkServer.initializeAndRun(args);
		} catch (QuorumPeerConfig.ConfigException e) {
		logger.warn("Caught exception while starting ZK", e);
		} catch (IOException e) {
		zooKeeperServerMain.initializeAndRun(args);
		} catch (QuorumPeerConfig.ConfigException \| IOException e) {
		logger.warn("Caught exception while starting ZK", e);
		throw new RuntimeException(e);
		}
		}
		}

		/**
		* Stops a local Zk instance, deleting its data directory
		*/
		public static void stop() {
		public void stop() {
		try {
		stopLocalZkServer(true);
		logger.info("zk server stopped");
		@@ -147,15 +168,17 @@ public class ZKServer {
		*
		* @param deleteDataDir Whether or not to delete the data directory
		*/
		private static synchronized void stopLocalZkServer(final boolean deleteDataDir) {
		if (zkServer != null) {
		private void stopLocalZkServer(final boolean deleteDataDir) {
		if (isStarted.compareAndSet(true, false)) {
		try {
		zkServer.shutdown();
		zkServer = null;
		if (zooKeeperServerMain == null) {
		return;
		}
		zooKeeperServerMain.shutdown();
		zooKeeperServerMain = null;
		if (deleteDataDir) {
		org.apache.commons.io.FileUtils.deleteDirectory(new File(dataDir));
		}
		isStarted.compareAndSet(true, false);
		} catch (Exception e) {
		logger.warn("Caught exception while stopping ZK server", e);
		throw new RuntimeException(e);

dolphinscheduler-service/src/test/java/org/apache/dolphinscheduler/service/zk/ZKServerTest.java

+32 −6

Original line number	Diff line number	Diff line
		@@ -18,18 +18,44 @@ package org.apache.dolphinscheduler.service.zk;

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

		// ZKServer is a process, can't unit test
		public class ZKServerTest {
		import java.util.concurrent.TimeUnit;
		import java.util.concurrent.atomic.AtomicReference;

		public class ZKServerTest {
		private static final Logger log = LoggerFactory.getLogger(ZKServerTest.class);

		@Test
		public void isStarted() {
		Assert.assertEquals(false, ZKServer.isStarted());
		public void testRunWithDefaultPort() {
		AtomicReference<ZKServer> zkServer = new AtomicReference<>();
		new Thread(() -> {
		zkServer.set(new ZKServer());
		zkServer.get().start();
		}).start();
		try {
		TimeUnit.SECONDS.sleep(5);
		Assert.assertEquals(true, zkServer.get().isStarted());
		} catch (InterruptedException e) {
		log.error("Thread interrupted", e);
		}
		zkServer.get().stop();
		}

		@Test
		public void stop() {
		ZKServer.stop();
		public void testRunWithCustomPort() {
		AtomicReference<ZKServer> zkServer = new AtomicReference<>();
		new Thread(() -> {
		zkServer.set(new ZKServer(2183, null));
		zkServer.get().start();
		}).start();
		try {
		TimeUnit.SECONDS.sleep(5);
		Assert.assertEquals(true, zkServer.get().isStarted());
		} catch (InterruptedException e) {
		log.error("Thread interrupted", e);
		}
		zkServer.get().stop();
		}
		}
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