Merge pull request #4430 from MattGill98/CUSTCOM-76

CUSTCOM-76 WebappClassLoader Synchronisation Test

appserver/web/war-util/src/test/java/org/glassfish/web/loader/WebappClassLoaderTest.java

@@ -0,0 +1,183 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright (c) [2020] Payara Foundation and/or its affiliates. All rights reserved.
+ *
+ * The contents of this file are subject to the terms of either the GNU
+ * General Public License Version 2 only ("GPL") or the Common Development
+ * and Distribution License("CDDL") (collectively, the "License").  You
+ * may not use this file except in compliance with the License.  You can
+ * obtain a copy of the License at
+ * https://github.com/payara/Payara/blob/master/LICENSE.txt
+ * See the License for the specific
+ * language governing permissions and limitations under the License.
+ *
+ * When distributing the software, include this License Header Notice in each
+ * file and include the License file at glassfish/legal/LICENSE.txt.
+ *
+ * GPL Classpath Exception:
+ * The Payara Foundation designates this particular file as subject to the "Classpath"
+ * exception as provided by the Payara Foundation in the GPL Version 2 section of the License
+ * file that accompanied this code.
+ *
+ * Modifications:
+ * If applicable, add the following below the License Header, with the fields
+ * enclosed by brackets [] replaced by your own identifying information:
+ * "Portions Copyright [year] [name of copyright owner]"
+ *
+ * Contributor(s):
+ * If you wish your version of this file to be governed by only the CDDL or
+ * only the GPL Version 2, indicate your decision by adding "[Contributor]
+ * elects to include this software in this distribution under the [CDDL or GPL
+ * Version 2] license."  If you don't indicate a single choice of license, a
+ * recipient has the option to distribute your version of this file under
+ * either the CDDL, the GPL Version 2 or to extend the choice of license to
+ * its licensees as provided above.  However, if you add GPL Version 2 code
+ * and therefore, elected the GPL Version 2 license, then the option applies
+ * only if the new code is made subject to such option by the copyright
+ * holder.
+ */
+package org.glassfish.web.loader;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+
+import org.apache.naming.resources.FileDirContext;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class WebappClassLoaderTest {
+
+    private static final int EXECUTION_COUNT = 100;
+
+    private CountDownLatch latch;
+
+    private ExecutorService executor;
+    private File junitJarFile;
+
+    @Before
+    public void setup() throws URISyntaxException {
+        // Run 3 methods at the same time, and make the pool large enough to increase
+        // the chance of a race condition
+        executor = Executors.newFixedThreadPool(60);
+
+        // Require a minimum number of executions before completing
+        latch = new CountDownLatch(EXECUTION_COUNT);
+
+        // Fetch any JAR to use for classloading
+        junitJarFile = new File(Test.class.getProtectionDomain().getCodeSource().getLocation().toURI());
+    }
+
+    @After
+    public void shutdown() throws InterruptedException {
+        if (executor != null) {
+            executor.shutdownNow();
+            assertTrue("Executor could not shutdown. This could mean there is a deadlock.",
+                    executor.awaitTermination(10, TimeUnit.SECONDS));
+        }
+    }
+
+    @Test
+    public void check_findResourceInternalFromJars_thread_safety() throws Exception {
+        final WebappClassLoader webappClassLoader = new WebappClassLoader(getClass().getClassLoader(), null);
+        webappClassLoader.start();
+        webappClassLoader.setResources(new FileDirContext());
+
+        CompletableFuture<Void> result = new CompletableFuture<>();
+
+        // Create the tasks to run
+        Runnable lookupTask = waitAndDo(result, () -> lookup(webappClassLoader));
+        Runnable addTask = waitAndDo(result, () -> add(webappClassLoader));
+        Runnable closeTask = waitAndDo(result, () -> webappClassLoader.closeJARs(true));
+
+        try {
+            // Run the methods at the same time
+            for (int i = 0; i < EXECUTION_COUNT; i++) {
+                executor.execute(addTask);
+                executor.execute(lookupTask);
+                executor.execute(closeTask);
+            }
+
+            // Wait for tasks to execute
+            assertTrue("The tasks didn't finish in the allowed time.",
+                    latch.await(20, TimeUnit.SECONDS));
+
+            // Check to see if any tasks completed exceptionally
+            result.getNow(null);
+        } finally {
+            webappClassLoader.close();
+        }
+    }
+
+    private void add(WebappClassLoader webappClassLoader) throws IOException {
+        List<JarFile> jarFiles = findJarFiles();
+
+        for (JarFile j : jarFiles) {
+            try {
+                webappClassLoader.addJar(junitJarFile.getName(), j, junitJarFile);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
+    private void lookup(WebappClassLoader webappClassLoader) throws Exception {
+        for (JarFile jarFile : findJarFiles()) {
+            for (JarEntry entry : Collections.list(jarFile.entries())) {
+                webappClassLoader.findResource(entry.getName());
+                // System.out.println("Looked up " + resourceEntry);
+                Thread.sleep(0, 100);
+            }
+        }
+    }
+
+    private List<JarFile> findJarFiles() throws IOException {
+        List<JarFile> jarFiles = new LinkedList<>();
+        for (int i = 0; i < 10; i++) {
+            jarFiles.add(new JarFile(junitJarFile));
+        }
+        return jarFiles;
+    }
+
+    /**
+     * Generate a task that will wait on the passed cyclic barrier before running
+     * the passed task. Record the result in the passed future
+     * 
+     * @param result where to store any encountered exceptions
+     * @param task   the task to run
+     * @return a new task
+     */
+    private Runnable waitAndDo(final CompletableFuture<Void> result, final ExceptionalRunnable task) {
+        return () -> {
+            try {
+                task.run();
+            } catch (Exception ex) {
+                result.completeExceptionally(ex);
+            } finally {
+                latch.countDown();
+            }
+        };
+    }
+
+    /**
+     * A runnable interface that allows exceptions
+     */
+    @FunctionalInterface
+    private interface ExceptionalRunnable {
+        void run() throws Exception;
+    }
+}