2commit

dependency-reduced-pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>org.example</groupId>
+  <artifactId>transientworker</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>17</source>
+          <target>17</target>
+        </configuration>
+      </plugin>
+      <plugin>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>3.2.4</version>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+            <configuration>
+              <transformers>
+                <transformer>
+                  <mainClass>Application</mainClass>
+                </transformer>
+              </transformers>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+  <properties>
+    <maven.compiler.target>17</maven.compiler.target>
+    <maven.compiler.source>17</maven.compiler.source>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+</project>

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>transientworker</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>17</source>
+                    <target>17</target>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.2.4</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <transformers>
+                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                                    <mainClass>Application</mainClass>
+                                </transformer>
+                            </transformers>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.zookeeper</groupId>
+            <artifactId>zookeeper</artifactId>
+            <version>3.9.1</version>
+        </dependency>
+    </dependencies>
+
+
+</project>
\ No newline at end of file

src/main/java/Application.java

+/*
+ *  MIT License
+ *
+ *  Copyright (c) 2019 Michael Pogrebinsky - Distributed Systems & Cloud Computing with Java
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in all
+ *  copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *  SOFTWARE.
+ */
+
+import org.apache.zookeeper.KeeperException;
+
+import java.io.IOException;
+
+public class Application {
+    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
+        Worker worker = new Worker();
+        worker.connectToZookeeper();
+        worker.work();
+    }
+}

src/main/java/NodeAgent.java

+import org.apache.zookeeper.*;
+import java.io.File;
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.List;
+
+public class NodeAgent implements Watcher {
+    private static final String ZOOKEEPER_ADDRESS = "192.168.144.134:2181";
+    private static final int SESSION_TIMEOUT = 3000;
+    private static final String NODES_ROOT = "/nodes";
+    private static final String WORKER_JAR_PATH = "C:\\Users\\J.N\\IdeaProjects\\auto-healer-zookeper\\transientworker\\target\\transientworker-1.0-SNAPSHOT.jar";
+
+    private ZooKeeper zooKeeper;
+    private String myTasksPath;
+
+    public void connectToZookeeper() throws IOException {
+        this.zooKeeper = new ZooKeeper(ZOOKEEPER_ADDRESS, SESSION_TIMEOUT, this);
+    }
+
+    public void registerNodeAndWatchTasks() throws KeeperException, InterruptedException, IOException {
+        ensurePath(NODES_ROOT, CreateMode.PERSISTENT);
+
+        String ipAddress = InetAddress.getLocalHost().getHostAddress();
+        String nodePath = NODES_ROOT + "/node_" + ipAddress;
+
+
+        ensurePath(nodePath, CreateMode.PERSISTENT);
+
+
+        String activePath = nodePath + "/active";
+        if (zooKeeper.exists(activePath, false) == null) {
+            zooKeeper.create(activePath, new byte[]{}, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
+        }
+
+
+        this.myTasksPath = nodePath + "/tasks";
+        ensurePath(myTasksPath, CreateMode.PERSISTENT);
+
+        System.out.println("Node Registered: " + nodePath + ". Watching tasks at: " + myTasksPath);
+        watchMyTasks();
+    }
+
+
+    private void ensurePath(String path, CreateMode mode) throws KeeperException, InterruptedException {
+        if (zooKeeper.exists(path, false) == null) {
+            zooKeeper.create(path, new byte[]{}, ZooDefs.Ids.OPEN_ACL_UNSAFE, mode);
+        }
+    }
+
+    private void watchMyTasks() throws KeeperException, InterruptedException {
+        List<String> tasks = zooKeeper.getChildren(myTasksPath, this);
+        System.out.println("Current tasks count: " + tasks.size());
+    }
+
+    @Override
+    public void process(WatchedEvent event) {
+        if (event.getType() == Event.EventType.NodeChildrenChanged && event.getPath().equals(myTasksPath)) {
+            handleNewTask();
+        } else if (event.getState() == Event.KeeperState.SyncConnected) {
+            System.out.println("Connected to Zookeeper");
+        }
+    }
+
+    private void handleNewTask() {
+        try {
+            startLocalWorker();
+            watchMyTasks(); // إعادة المراقبة
+        } catch (Exception e) { e.printStackTrace(); }
+    }
+
+    private void startLocalWorker() throws IOException {
+        File jarFile = new File(WORKER_JAR_PATH);
+        ProcessBuilder pb = new ProcessBuilder("java", "-jar", jarFile.getAbsolutePath());
+        pb.inheritIO();
+        pb.directory(jarFile.getParentFile());
+        System.out.println("New worker launched locally!");
+        pb.start();
+    }
+
+    public static void main(String[] args) throws Exception {
+        NodeAgent agent = new NodeAgent();
+        agent.connectToZookeeper();
+        agent.registerNodeAndWatchTasks();
+        synchronized (agent.zooKeeper) { agent.zooKeeper.wait(); }
+    }
+}
\ No newline at end of file

src/main/java/Worker.java

+/*
+ *  MIT License
+ *
+ *  Copyright (c) 2019 Michael Pogrebinsky - Distributed Systems & Cloud Computing with Java
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to deal
+ *  in the Software without restriction, including without limitation the rights
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *  copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in all
+ *  copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *  SOFTWARE.
+ */
+
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.ZooKeeper;
+
+import java.io.IOException;
+import java.util.Random;
+import java.util.concurrent.locks.LockSupport;
+
+public class Worker {
+    private static final String ZOOKEEPER_ADDRESS = "192.168.144.134:2181";
+    private static final int SESSION_TIMEOUT = 3000;
+
+    // Parent Znode where each worker stores an ephemeral child to indicate it is alive
+    private static final String AUTOHEALER_ZNODES_PATH = "/workers";
+
+    private static final float CHANCE_TO_FAIL = 0.1F;
+
+    private final Random random = new Random();
+    private ZooKeeper zooKeeper;
+
+    public void connectToZookeeper() throws IOException {
+        this.zooKeeper = new ZooKeeper(ZOOKEEPER_ADDRESS, SESSION_TIMEOUT, event -> {
+        });
+    }
+
+    public void work() throws KeeperException, InterruptedException {
+        addChildZnode();
+
+        while (true) {
+            System.out.println("Working...");
+            LockSupport.parkNanos(1000);
+            if (random.nextFloat() < CHANCE_TO_FAIL) {
+                System.out.println("Critical error happened");
+                throw new RuntimeException("Oops");
+            }
+        }
+    }
+
+    private void addChildZnode() throws KeeperException, InterruptedException {
+        zooKeeper.create(AUTOHEALER_ZNODES_PATH + "/worker_",
+                new byte[]{},
+                ZooDefs.Ids.OPEN_ACL_UNSAFE,
+                CreateMode.EPHEMERAL_SEQUENTIAL);
+    }
+}

target/maven-archiver/pom.properties

+artifactId=transientworker
+groupId=org.example
+version=1.0-SNAPSHOT

target/maven-status/maven-compiler-plugin/compile/default-compile/createdFiles.lst

+Application.class
+Worker.class
+NodeAgent.class

target/maven-status/maven-compiler-plugin/compile/default-compile/inputFiles.lst

+C:\Users\J.N\IdeaProjects\auto-healer-zookeper\transientworker\src\main\java\Application.java
+C:\Users\J.N\IdeaProjects\auto-healer-zookeper\transientworker\src\main\java\NodeAgent.java
+C:\Users\J.N\IdeaProjects\auto-healer-zookeper\transientworker\src\main\java\Worker.java