add better messaging and error handling

docs/content/Tutorial:-Loading-Your-Data-Part-1.md

@@ -94,6 +94,7 @@ druid.db.connector.user=druid
 druid.db.connector.password=diurd
 
 druid.selectors.indexing.serviceName=overlord
+druid.indexer.queue.startDelay=PT0M
 druid.indexer.runner.javaOpts="-server -Xmx1g"
 druid.indexer.runner.startPort=8088
 druid.indexer.fork.property.druid.computation.buffer.size=268435456
@@ -246,17 +247,19 @@ Issuing a [TimeBoundaryQuery](TimeBoundaryQuery.html) should yield:
 } ]
 ```
 
-Problems?
+Console
----------
+--------
 
-If you decide to reuse the local firehose to ingest your own data and if you run into problems, you can read the individual task logs at:
+The indexing service overlord has a console located as:
 
 ```bash
-<Current working directory>/log/<task_id>.log
+localhost:8087/console.html
-
 ```
 
-One thing to note is that the log file will only exist once the task completes with either SUCCESS or FAILURE.
+On this console, you can look at statuses and logs of recently submitted and completed tasks.
+
+If you decide to reuse the local firehose to ingest your own data and if you run into problems, you can use the console to read the individual task logs.
+
 Task logs can be stored locally or uploaded to [Deep Storage](Deep-Storage.html). More information about how to configure this is [here](Configuration.html).
 
 Most common data ingestion problems are around timestamp formats and other malformed data issues.

indexing-service/src/main/java/io/druid/indexing/overlord/http/OverlordResource.java

@@ -368,6 +368,9 @@ public class OverlordResource
   @Produces("application/json")
   public Response getScalingState()
   {
+    if (!taskMaster.getResourceManagementScheduler().isPresent()) {
+      return Response.ok().build();
+    }
     return asLeaderWith(
         taskMaster.getResourceManagementScheduler(),
         new Function<ResourceManagementScheduler, Response>()

indexing-service/src/main/resources/indexer_static/console.html

@@ -59,8 +59,8 @@
     <div class="workers_loading">Loading Workers... this may take a few minutes</div>
     <table id="workerTable"></table>
 
-    <h2>Event Log</h2>
+    <h2>Autoscaling Activity</h2>
-    <div class="events_loading">Loading Event Log... this may take a few minutes</div>
+    <div class="events_loading">Loading Autoscaling Activities... this may take a few minutes</div>
     <table id="eventTable"></table>
 </div>
 </body>

server/src/main/java/io/druid/segment/realtime/firehose/LocalFirehoseFactory.java

@@ -23,6 +23,7 @@ import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.api.client.repackaged.com.google.common.base.Throwables;
 import com.google.common.collect.Lists;
+import com.metamx.common.ISE;
 import io.druid.data.input.Firehose;
 import io.druid.data.input.FirehoseFactory;
 import io.druid.data.input.impl.FileIteratingFirehose;
@@ -78,9 +79,7 @@ public class LocalFirehoseFactory implements FirehoseFactory
   @Override
   public Firehose connect() throws IOException
   {
-    final LinkedList<File> files = Lists.<File>newLinkedList(
+    File[] foundFiles = baseDir.listFiles(
-        Arrays.<File>asList(
-            baseDir.listFiles(
         new FilenameFilter()
         {
           @Override
@@ -89,10 +88,17 @@ public class LocalFirehoseFactory implements FirehoseFactory
             return name.contains(filter);
           }
         }
-            )
-        )
     );
 
+    if (foundFiles == null || foundFiles.length == 0) {
+      throw new ISE("Found no files to ingest! Check your schema.");
+    }
+
+    final LinkedList<File> files = Lists.<File>newLinkedList(
+        Arrays.asList(foundFiles)
+    );
+
+
     return new FileIteratingFirehose(
         new Iterator<LineIterator>()
         {