be nice and close all resources on shutdown

src/main/groovy/com/github/lookout/verspaetung/KafkaPoller.groovy

@@ -79,6 +79,7 @@ class KafkaPoller extends Thread {
 
             Thread.sleep(delay.value())
         }
+        disconnectConsumers()
     }
 
     private void slower(Delay delay) {
@@ -178,7 +179,6 @@ class KafkaPoller extends Thread {
      */
     void die() {
         this.keepRunning = false
-        disconnectConsumers()
     }
 
     private void disconnectConsumers() {

src/main/groovy/com/github/lookout/verspaetung/Main.groovy

@@ -126,8 +126,9 @@ class Main {
         /* Assuming that most people aren't needing to run Storm-based watchers
          * as well
          */
+        KafkaSpoutTreeWatcher stormWatcher = null
         if (cli.hasOption('s')) {
-            KafkaSpoutTreeWatcher stormWatcher = new KafkaSpoutTreeWatcher(client,
+            stormWatcher = new KafkaSpoutTreeWatcher(client,
                                                                            watchedTopics,
                                                                            consumerOffsets)
             stormWatcher.onConsumerData << gaugeRegistrar
@@ -155,6 +156,18 @@ class Main {
         /* Start the reporter if we've got it */
         reporter?.start(delayInSeconds, TimeUnit.SECONDS)
 
+        // shutdown threads
+        Runtime.getRuntime().addShutdownHook(new Thread() {
+                                                 public void run() {
+                                                     Main.logger.info("showdown threads")
+                                                     poller.die()
+                                                     consumerWatcher.close()
+                                                     if (stormWatcher != null) {
+                                                         stormWatcher.close()
+                                                     }
+                                                     poller.join()
+                                                 }
+                                             });
         logger.info('Starting wait loop...')
         synchronized(this) {
             wait()

src/main/groovy/com/github/lookout/verspaetung/zk/AbstractTreeWatcher.groovy

@@ -47,5 +47,13 @@ abstract class AbstractTreeWatcher implements TreeCacheListener {
         return this
     }
 
+    /**
+     * Close our internal cache and return ourselves for API cleanliness
+     */
+    AbstractTreeWatcher close() {
+        this.cache?.close()
+        return this
+    }
+
     abstract void childEvent(CuratorFramework client, TreeCacheEvent event)
 }