Realtime: Delay firehose connection until job is started.

Some firehoses (like the Kafka firehose) acquire input resources when they
connect, so it helps to delay this until after plumber.startJob() runs.

indexing-service/src/main/java/io/druid/indexing/common/task/RealtimeIndexTask.java

@@ -167,10 +167,6 @@ public class RealtimeIndexTask extends AbstractTask
 
     boolean normalExit = true;
 
-    // Set up firehose
-    final Period intermediatePersistPeriod = spec.getTuningConfig().getIntermediatePersistPeriod();
-    final Firehose firehose = spec.getIOConfig().getFirehoseFactory().connect(spec.getDataSchema().getParser());
-
     // It would be nice to get the PlumberSchool in the constructor.  Although that will need jackson injectables for
     // stuff like the ServerView, which seems kind of odd?  Perhaps revisit this when Guice has been introduced.
 
@@ -280,12 +276,19 @@ public class RealtimeIndexTask extends AbstractTask
 
     this.plumber = plumberSchool.findPlumber(dataSchema, tuningConfig, fireDepartment.getMetrics());
 
+    // Delay firehose connection to avoid claiming input resources while the plumber is starting up.
+    Firehose firehose = null;
+
     try {
       plumber.startJob();
 
       // Set up metrics emission
       toolbox.getMonitorScheduler().addMonitor(metricsMonitor);
 
+      // Set up firehose
+      final Period intermediatePersistPeriod = spec.getTuningConfig().getIntermediatePersistPeriod();
+      firehose = spec.getIOConfig().getFirehoseFactory().connect(spec.getDataSchema().getParser());
+
       // Time to read data!
       long nextFlush = new DateTime().plus(intermediatePersistPeriod).getMillis();
       while (firehose.hasMore()) {
@@ -338,6 +341,7 @@ public class RealtimeIndexTask extends AbstractTask
           log.makeAlert(e, "Failed to finish realtime task").emit();
         }
         finally {
+          // firehose will be non-null since normalExit is true
           CloseQuietly.close(firehose);
           toolbox.getMonitorScheduler().removeMonitor(metricsMonitor);
         }

server/src/main/java/io/druid/segment/realtime/RealtimeManager.java

@@ -18,9 +18,7 @@
 package io.druid.segment.realtime;
 
 
-import com.fasterxml.jackson.annotation.JacksonInject;
 import com.google.common.base.Function;
-import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Maps;
@@ -33,7 +31,6 @@ import com.metamx.common.parsers.ParseException;
 import com.metamx.emitter.EmittingLogger;
 import io.druid.data.input.Firehose;
 import io.druid.data.input.InputRow;
-import io.druid.guice.annotations.Processing;
 import io.druid.query.FinalizeResultsQueryRunner;
 import io.druid.query.NoopQueryRunner;
 import io.druid.query.Query;
@@ -58,7 +55,6 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.ExecutorService;
 
 /**
  */
@@ -68,24 +64,20 @@ public class RealtimeManager implements QuerySegmentWalker
 
   private final List<FireDepartment> fireDepartments;
   private final QueryRunnerFactoryConglomerate conglomerate;
-  private ExecutorService executorService;
 
   /**
    * key=data source name,value=FireChiefs of all partition of that data source
    */
   private final Map<String, List<FireChief>> chiefs;
 
-
   @Inject
   public RealtimeManager(
       List<FireDepartment> fireDepartments,
-      QueryRunnerFactoryConglomerate conglomerate,
-      @JacksonInject @Processing ExecutorService executorService
+      QueryRunnerFactoryConglomerate conglomerate
   )
   {
     this.fireDepartments = fireDepartments;
     this.conglomerate = conglomerate;
-    this.executorService = executorService;
 
     this.chiefs = Maps.newHashMap();
   }
@@ -112,7 +104,6 @@ public class RealtimeManager implements QuerySegmentWalker
           )
       );
       chief.setDaemon(true);
-      chief.init();
       chief.start();
     }
   }
@@ -188,8 +179,8 @@ public class RealtimeManager implements QuerySegmentWalker
   {
     private final FireDepartment fireDepartment;
     private final FireDepartmentMetrics metrics;
+    private final RealtimeTuningConfig config;
 
-    private volatile RealtimeTuningConfig config = null;
     private volatile Firehose firehose = null;
     private volatile Plumber plumber = null;
     private volatile boolean normalExit = true;
@@ -199,26 +190,42 @@ public class RealtimeManager implements QuerySegmentWalker
     )
     {
       this.fireDepartment = fireDepartment;
-
+      this.config = fireDepartment.getTuningConfig();
       this.metrics = fireDepartment.getMetrics();
     }
 
-    public void init() throws IOException
+    public Firehose initFirehose()
     {
-      config = fireDepartment.getTuningConfig();
-
       synchronized (this) {
-        try {
-          log.info("Calling the FireDepartment and getting a Firehose.");
-          firehose = fireDepartment.connect();
-          log.info("Firehose acquired!");
+        if (firehose == null) {
+          try {
+            log.info("Calling the FireDepartment and getting a Firehose.");
+            firehose = fireDepartment.connect();
+            log.info("Firehose acquired!");
+          }
+          catch (IOException e) {
+            throw Throwables.propagate(e);
+          }
+        } else {
+          log.warn("Firehose already connected, skipping initFirehose().");
+        }
+
+        return firehose;
+      }
+    }
+
+    public Plumber initPlumber()
+    {
+      synchronized (this) {
+        if (plumber == null) {
           log.info("Someone get us a plumber!");
           plumber = fireDepartment.findPlumber();
           log.info("We have our plumber!");
+        } else {
+          log.warn("Plumber already trained, skipping initPlumber().");
         }
-        catch (IOException e) {
-          throw Throwables.propagate(e);
-        }
+
+        return plumber;
       }
     }
 
@@ -230,13 +237,15 @@ public class RealtimeManager implements QuerySegmentWalker
     @Override
     public void run()
     {
-      verifyState();
-
+      plumber = initPlumber();
       final Period intermediatePersistPeriod = config.getIntermediatePersistPeriod();
 
       try {
         plumber.startJob();
 
+        // Delay firehose connection to avoid claiming input resources while the plumber is starting up.
+        firehose = initFirehose();
+
         long nextFlush = new DateTime().plus(intermediatePersistPeriod).getMillis();
         while (firehose.hasMore()) {
           InputRow inputRow = null;
@@ -310,15 +319,6 @@ public class RealtimeManager implements QuerySegmentWalker
       }
     }
 
-    private void verifyState()
-    {
-      Preconditions.checkNotNull(config, "config is null, init() must be called first.");
-      Preconditions.checkNotNull(firehose, "firehose is null, init() must be called first.");
-      Preconditions.checkNotNull(plumber, "plumber is null, init() must be called first.");
-
-      log.info("FireChief[%s] state ok.", fireDepartment.getDataSchema().getDataSource());
-    }
-
     public <T> QueryRunner<T> getQueryRunner(Query<T> query)
     {
       QueryRunnerFactory<T, Query<T>> factory = conglomerate.findFactory(query);

server/src/test/java/io/druid/segment/realtime/RealtimeManagerTest.java

@@ -118,7 +118,6 @@ public class RealtimeManagerTest
                 tuningConfig
             )
         ),
-        null,
         null
     );
   }