narendly commented on a change in pull request #1169:
URL: https://github.com/apache/helix/pull/1169#discussion_r470080833
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File path: helix-core/src/main/java/org/apache/helix/task/TaskStateModel.java
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@@ -283,6 +287,68 @@ public void reset() {
}
}
+ /**
+ * Loads className using classLoader
+ * @param classLoader
+ * @param className
+ * @return Class className loaded by classLoader
+ */
+ private Class loadClass(URLClassLoader classLoader, String className) {
+ try {
+ return classLoader.loadClass(className);
+ } catch (ClassNotFoundException e) {
+ LOG.error("Failed to load Task class " + className + " for new task in
instance " + _manager
+ .getInstanceName() + " in cluster " + _manager.getClusterName() +
".");
+ throw new IllegalStateException("Class not found for task");
+ }
+ }
+
+ /**
+ * Loads Task and TaskFactory classes for command input from
+ * a JAR file, and registers the TaskFactory in _taskFactoryRegistry.
+ * @param command The command indicating what task to be loaded
+ */
+ private void loadNewTask(String command) {
+ // If the path for dynamic tasks doesn't exist, skip loading the task
+ if (!_manager.getHelixDataAccessor().getBaseDataAccessor()
+ .exists(TaskConstants.DYNAMICALLY_LOADED_TASK_PATH, 0)) {
+ return;
+ }
+
+ // Read DynamicTaskConfig containing task definition information.
+ DynamicTaskConfig taskConfig = new DynamicTaskConfig(
+ _manager.getHelixDataAccessor().getBaseDataAccessor()
+ .get(TaskConstants.DYNAMICALLY_LOADED_TASK_PATH + "/" + command,
null, 0));
+ if (taskConfig.getTaskConfigZNRecord() == null) {
+ LOG.error("Failed to read ZNRecord for task " + command + " for instance
" + _manager
+ .getInstanceName() + " in cluster " + _manager.getClusterName() +
".");
+ throw new IllegalArgumentException("No ZNRecord for task " + command);
+ }
+
+ // Open the JAR file containing Task(s) and TaskFactory classes.
+ JarLoader jarLoader = new LocalJarLoader();
+ URL taskJarUrl = jarLoader.loadJar(taskConfig.getJarFilePath());
+
+ // Import Task(s) class(es).
+ URLClassLoader classLoader = URLClassLoader.newInstance(new
URL[]{taskJarUrl});
+ for (String taskClass : taskConfig.getTaskClassesFqns()) {
+ loadClass(classLoader, taskClass);
+ }
+
+ try {
+ // Import and instantiate TaskFactory class.
+ TaskFactory taskFactory =
+ (TaskFactory) loadClass(classLoader,
taskConfig.getTaskFactoryFqn()).newInstance();
+
+ // Register the TaskFactory.
+ _taskFactoryRegistry.put(command, taskFactory);
Review comment:
nit: this piece of code could sit outside the try-catch?
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