CombiningFirehoseFactory

can be used to ingest data from multiple sources.

server/src/main/java/io/druid/guice/FirehoseModule.java

@@ -26,6 +26,7 @@ import com.google.inject.Binder;
 import io.druid.data.input.ProtoBufInputRowParser;
 import io.druid.initialization.DruidModule;
 import io.druid.segment.realtime.firehose.ClippedFirehoseFactory;
+import io.druid.segment.realtime.firehose.CombiningFirehoseFactory;
 import io.druid.segment.realtime.firehose.EventReceiverFirehoseFactory;
 import io.druid.segment.realtime.firehose.IrcFirehoseFactory;
 import io.druid.segment.realtime.firehose.LocalFirehoseFactory;
@@ -53,7 +54,8 @@ public class FirehoseModule implements DruidModule
                 new NamedType(TimedShutoffFirehoseFactory.class, "timed"),
                 new NamedType(IrcFirehoseFactory.class, "irc"),
                 new NamedType(LocalFirehoseFactory.class, "local"),
-                new NamedType(EventReceiverFirehoseFactory.class, "receiver")
+                new NamedType(EventReceiverFirehoseFactory.class, "receiver"),
+                new NamedType(CombiningFirehoseFactory.class, "combining")
             )
     );
   }

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

@@ -0,0 +1,125 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.segment.realtime.firehose;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.google.api.client.repackaged.com.google.common.base.Preconditions;
+import com.google.api.client.repackaged.com.google.common.base.Throwables;
+import io.druid.data.input.Firehose;
+import io.druid.data.input.FirehoseFactory;
+import io.druid.data.input.InputRow;
+import io.druid.data.input.impl.InputRowParser;
+
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * Creates firehose that combines data from different Firehoses. Useful for ingesting data from multiple sources.
+ */
+public class CombiningFirehoseFactory implements FirehoseFactory<InputRowParser>
+{
+  private final List<FirehoseFactory> delegateFactoryList;
+
+  @JsonCreator
+  public CombiningFirehoseFactory(
+      @JsonProperty("delegates") List<FirehoseFactory> delegateFactoryList
+  )
+  {
+    Preconditions.checkArgument(!delegateFactoryList.isEmpty());
+    this.delegateFactoryList = delegateFactoryList;
+  }
+
+  @Override
+  public Firehose connect(InputRowParser parser) throws IOException
+  {
+    return new CombiningFirehose(parser);
+  }
+
+  @Override
+  public InputRowParser getParser()
+  {
+    return delegateFactoryList.get(0).getParser();
+  }
+
+  @JsonProperty("delegates")
+  public List<FirehoseFactory> getDelegateFactoryList()
+  {
+    return delegateFactoryList;
+  }
+
+  public class CombiningFirehose implements Firehose
+  {
+    private final InputRowParser parser;
+    private final Iterator<FirehoseFactory> firehoseFactoryIterator;
+    private volatile Firehose currentFirehose;
+
+    public CombiningFirehose(InputRowParser parser) throws IOException
+    {
+      this.firehoseFactoryIterator = delegateFactoryList.iterator();
+      this.parser = parser;
+      nextFirehose();
+    }
+
+    private void nextFirehose()
+    {
+      if (firehoseFactoryIterator.hasNext()) {
+        try {
+          if (currentFirehose != null) {
+            currentFirehose.close();
+          }
+          currentFirehose = firehoseFactoryIterator.next().connect(parser);
+        }
+        catch (IOException e) {
+          Throwables.propagate(e);
+        }
+      }
+    }
+
+    @Override
+    public boolean hasMore()
+    {
+      return currentFirehose.hasMore();
+    }
+
+    @Override
+    public InputRow nextRow()
+    {
+      InputRow rv = currentFirehose.nextRow();
+      if (!currentFirehose.hasMore()) {
+        nextFirehose();
+      }
+      return rv;
+    }
+
+    @Override
+    public Runnable commit()
+    {
+      return currentFirehose.commit();
+    }
+
+    @Override
+    public void close() throws IOException
+    {
+      currentFirehose.close();
+    }
+  }
+}

server/src/test/java/io/druid/realtime/firehose/CombiningFirehoseFactoryTest.java

@@ -0,0 +1,147 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2012, 2013, 2014  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.realtime.firehose;
+
+import com.google.common.collect.Lists;
+import com.metamx.common.parsers.ParseException;
+import io.druid.data.input.Firehose;
+import io.druid.data.input.FirehoseFactory;
+import io.druid.data.input.InputRow;
+import io.druid.data.input.impl.InputRowParser;
+import io.druid.segment.realtime.firehose.CombiningFirehoseFactory;
+import io.druid.utils.Runnables;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+
+public class CombiningFirehoseFactoryTest
+{
+
+  @Test
+  public void testCombiningfirehose() throws IOException
+  {
+    List<InputRow> list1 = Arrays.asList(makeRow(1, 1), makeRow(2, 2));
+    List<InputRow> list2 = Arrays.asList(makeRow(3, 3), makeRow(4, 4));
+    FirehoseFactory combiningFactory = new CombiningFirehoseFactory(
+        Arrays.<FirehoseFactory>asList(
+            new ListFirehoseFactory(
+                list1
+            ), new ListFirehoseFactory(list2)
+        )
+    );
+    final Firehose firehose = combiningFactory.connect(null);
+    for (int i = 1; i < 5; i++) {
+      Assert.assertTrue(firehose.hasMore());
+      final InputRow inputRow = firehose.nextRow();
+      Assert.assertEquals(i, inputRow.getTimestampFromEpoch());
+      Assert.assertEquals(i, inputRow.getFloatMetric("test"), 0);
+    }
+    Assert.assertFalse(firehose.hasMore());
+  }
+
+  private InputRow makeRow(final long timestamp, final float metricValue)
+  {
+    return new InputRow()
+    {
+      @Override
+      public List<String> getDimensions()
+      {
+        return Arrays.asList("testDim");
+      }
+
+      @Override
+      public long getTimestampFromEpoch()
+      {
+        return timestamp;
+      }
+
+      @Override
+      public List<String> getDimension(String dimension)
+      {
+        return Lists.newArrayList();
+      }
+
+      @Override
+      public float getFloatMetric(String metric)
+      {
+        return metricValue;
+      }
+
+      @Override
+      public Object getRaw(String dimension)
+      {
+        return null;
+      }
+
+    };
+  }
+
+  public static class ListFirehoseFactory implements FirehoseFactory<InputRowParser>
+  {
+    private final List<InputRow> rows;
+
+    ListFirehoseFactory(List<InputRow> rows)
+    {
+      this.rows = rows;
+    }
+
+    @Override
+    public Firehose connect(InputRowParser inputRowParser) throws IOException, ParseException
+    {
+      final Iterator<InputRow> iterator = rows.iterator();
+      return new Firehose()
+      {
+        @Override
+        public boolean hasMore()
+        {
+          return iterator.hasNext();
+        }
+
+        @Override
+        public InputRow nextRow()
+        {
+          return iterator.next();
+        }
+
+        @Override
+        public Runnable commit()
+        {
+          return Runnables.getNoopRunnable();
+        }
+
+        @Override
+        public void close() throws IOException
+        {
+          //
+        }
+      };
+    }
+
+    @Override
+    public InputRowParser getParser()
+    {
+      return null;
+    }
+  }
+}