1 files changed, 105 insertions, 0 deletions
diff --git a/mod/designtool/designtool-web/src/main/java/org/apache/nifi/nar/DCAEAutoLoader.java b/mod/designtool/designtool-web/src/main/java/org/apache/nifi/nar/DCAEAutoLoader.java
new file mode 100644
index 0000000..ec15ba6
--- /dev/null
+++ b/mod/designtool/designtool-web/src/main/java/org/apache/nifi/nar/DCAEAutoLoader.java
@@ -0,0 +1,105 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed 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.
+ * ============LICENSE_END=========================================================
+ */
+package org.apache.nifi.nar;
+
+import org.apache.nifi.bundle.Bundle;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URL;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.Executors;
+
+/**
+ * Uses the Java executor service scheduler to continuously load new DCAE jars
+ */
+public class DCAEAutoLoader {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(DCAEAutoLoader.class);
+
+    private static final long POLL_INTERVAL_MS = 5000;
+
+    /**
+     * Runnable task that grabs list of remotely stored jars, identifies ones that haven't
+     * been processed, builds Nifi bundles for those unprocessed ones and loads them into
+     * the global extension manager.
+     */
+    private static class LoaderTask implements Runnable {
+
+        private static final Logger LOGGER = LoggerFactory.getLogger(LoaderTask.class);
+
+        private final URI indexJsonDcaeJars;
+        private final ExtensionDiscoveringManager extensionManager;
+        private final Set<URL> processed = new LinkedHashSet();
+
+        private LoaderTask(URI indexJsonDcaeJars, ExtensionDiscoveringManager extensionManager) {
+            this.indexJsonDcaeJars = indexJsonDcaeJars;
+            this.extensionManager = extensionManager;
+        }
+
+        @Override
+        public void run() {
+            try {
+                List<URL> toProcess = DCAEClassLoaders.getDCAEJarsURLs(this.indexJsonDcaeJars);
+                toProcess.removeAll(processed);
+
+                if (!toProcess.isEmpty()) {
+                    Set<Bundle> bundles = DCAEClassLoaders.createDCAEBundles(toProcess);
+                    this.extensionManager.discoverExtensions(bundles);
+                    processed.addAll(toProcess);
+
+                    LOGGER.info(String.format("#Added DCAE bundles: %d, #Total DCAE bundles: %d ",
+                        bundles.size(), processed.size()));
+                }
+            } catch (final Exception e) {
+                LOGGER.error("Error loading DCAE jars due to: " + e.getMessage(), e);
+            }
+        }
+    }
+
+    private final ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
+    private ScheduledFuture taskFuture;
+
+    public synchronized void start(URI indexJsonDcaeJars, final ExtensionDiscoveringManager extensionManager) {
+        // Restricting to a single thread
+        if (taskFuture != null && !taskFuture.isCancelled()) {
+            return;
+        }
+
+        LOGGER.info("Starting DCAE Auto-Loader: {}", new Object[]{indexJsonDcaeJars});
+
+        LoaderTask task = new LoaderTask(indexJsonDcaeJars, extensionManager);
+        this.taskFuture = executor.scheduleAtFixedRate(task, 0, POLL_INTERVAL_MS, TimeUnit.MILLISECONDS);
+        LOGGER.info("DCAE Auto-Loader started");
+    }
+
+    public synchronized void stop() {
+        if (this.taskFuture != null) {
+            this.taskFuture.cancel(true);
+            LOGGER.info("DCAE Auto-Loader stopped");
+        }
+    }
+
+}