make RTR idempotent to multiple run requests for same task, because higher...

make RTR idempotent to multiple run requests for same task, because higher level things in the indexing service require this behaviour

indexing-service/src/main/java/com/metamx/druid/indexing/coordinator/RemoteTaskRunner.java

@@ -265,9 +265,6 @@ public class RemoteTaskRunner implements TaskRunner, TaskLogProvider
               task.getId(),
               new RemoteTaskRunnerWorkItem(task, SettableFuture.<TaskStatus>create())
           );
-        } else {
-          log.info("Bootstrap didn't find %s running. Running it again", task.getId());
-          run(task);
         }
       }
     }
@@ -284,8 +281,15 @@ public class RemoteTaskRunner implements TaskRunner, TaskLogProvider
   @Override
   public ListenableFuture<TaskStatus> run(final Task task)
   {
-    if (runningTasks.containsKey(task.getId()) || pendingTasks.containsKey(task.getId())) {
-      throw new ISE("Assigned a task[%s] that is already running or pending, WTF is happening?!", task.getId());
+    RemoteTaskRunnerWorkItem runningTask = runningTasks.get(task.getId());
+    if (runningTask != null) {
+      log.info("Assigned a task[%s] that is already running, not doing anything", task.getId());
+      return runningTask.getResult();
+    }
+    RemoteTaskRunnerWorkItem pendingTask = pendingTasks.get(task.getId());
+    if (pendingTask != null) {
+      log.info("Assigned a task[%s] that is already pending, not doing anything", task.getId());
+      return pendingTask.getResult();
     }
     RemoteTaskRunnerWorkItem taskRunnerWorkItem = new RemoteTaskRunnerWorkItem(
         task,
@@ -686,9 +690,12 @@ public class RemoteTaskRunner implements TaskRunner, TaskLogProvider
         }
     );
     sortedWorkers.addAll(zkWorkers.values());
+    final String configMinWorkerVer = workerSetupData.get().getMinVersion();
+    final String minWorkerVer = configMinWorkerVer == null ? config.getWorkerVersion() : configMinWorkerVer;
+
     for (ZkWorker zkWorker : sortedWorkers) {
       if (zkWorker.canRunTask(task) &&
-          zkWorker.getWorker().getVersion().compareTo(workerSetupData.get().getMinVersion()) >= 0) {
+          zkWorker.getWorker().getVersion().compareTo(minWorkerVer) >= 0) {
         return zkWorker;
       }
     }

indexing-service/src/main/java/com/metamx/druid/indexing/coordinator/config/RemoteTaskRunnerConfig.java

@@ -23,6 +23,7 @@ import com.metamx.druid.indexing.common.config.IndexerZkConfig;
 import org.joda.time.Duration;
 import org.skife.config.Config;
 import org.skife.config.Default;
+import org.skife.config.DefaultNull;
 
 /**
  */
@@ -35,4 +36,8 @@ public abstract class RemoteTaskRunnerConfig extends IndexerZkConfig
   @Config("druid.curator.compression.enable")
   @Default("false")
   public abstract boolean enableCompression();
+
+  @Config("druid.indexer.worker.version")
+  @DefaultNull
+  public abstract String getWorkerVersion();
 }

indexing-service/src/test/java/com/metamx/druid/indexing/coordinator/RemoteTaskRunnerTest.java

@@ -109,17 +109,6 @@ public class RemoteTaskRunnerTest
     remoteTaskRunner.run(task);
   }
 
-  @Test(expected = ISE.class)
-  public void testExceptionThrownWithExistingTask() throws Exception
-  {
-    doSetup();
-
-    remoteTaskRunner.run(makeTask(TaskStatus.running("task")));
-    remoteTaskRunner.run(
-        makeTask(TaskStatus.running("task"))
-    );
-  }
-
   @Test
   public void testRunTooMuchZKData() throws Exception
   {
@@ -415,5 +404,11 @@ public class RemoteTaskRunnerTest
     {
       return 1000;
     }
+
+    @Override
+    public String getWorkerVersion()
+    {
+      return "";
+    }
   }
 }