allow router to override selection based on config

server/src/main/java/io/druid/server/router/PriorityTieredBrokerSelectorStrategy.java

@@ -0,0 +1,46 @@
+/*
+ * 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.server.router;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.Iterables;
+import io.druid.query.Query;
+
+/**
+ */
+public class PriorityTieredBrokerSelectorStrategy implements TieredBrokerSelectorStrategy
+{
+  @Override
+  public Optional<String> getBrokerServiceName(TieredBrokerConfig tierConfig, Query query)
+  {
+    final int priority = query.getContextPriority(0);
+
+    if (priority < 0) {
+      return Optional.of(
+          Iterables.getFirst(
+              tierConfig.getTierToBrokerMap().values(),
+              tierConfig.getDefaultBrokerServiceName()
+          )
+      );
+    }
+
+    return Optional.absent();
+  }
+}

server/src/main/java/io/druid/server/router/TieredBrokerConfig.java

@@ -54,6 +54,10 @@ public class TieredBrokerConfig
   @NotNull
   private Period pollPeriod = new Period("PT1M");
 
+  @JsonProperty
+  @NotNull
+  private String strategies = "[{\"type\":\"timeBoundary\"},{\"type\":\"priority\"}]";
+
   // tier, <bard, numThreads>
   public LinkedHashMap<String, String> getTierToBrokerMap()
   {
@@ -88,4 +92,9 @@ public class TieredBrokerConfig
   {
     return pollPeriod;
   }
+
+  public String getStrategies()
+  {
+    return strategies;
+  }
 }

server/src/main/java/io/druid/server/router/TieredBrokerHostSelector.java

@@ -19,6 +19,7 @@
 
 package io.druid.server.router;
 
+import com.google.common.base.Optional;
 import com.google.common.base.Throwables;
 import com.google.common.collect.Iterables;
 import com.google.inject.Inject;
@@ -30,7 +31,6 @@ import io.druid.client.selector.HostSelector;
 import io.druid.curator.discovery.ServerDiscoveryFactory;
 import io.druid.curator.discovery.ServerDiscoverySelector;
 import io.druid.query.Query;
-import io.druid.query.timeboundary.TimeBoundaryQuery;
 import io.druid.server.coordinator.rules.LoadRule;
 import io.druid.server.coordinator.rules.Rule;
 import org.joda.time.DateTime;
@@ -50,6 +50,7 @@ public class TieredBrokerHostSelector<T> implements HostSelector<T>
   private final TieredBrokerConfig tierConfig;
   private final ServerDiscoveryFactory serverDiscoveryFactory;
   private final ConcurrentHashMap<String, ServerDiscoverySelector> selectorMap = new ConcurrentHashMap<>();
+  private final List<TieredBrokerSelectorStrategy> strategies;
 
   private final Object lock = new Object();
 
@@ -59,12 +60,14 @@ public class TieredBrokerHostSelector<T> implements HostSelector<T>
   public TieredBrokerHostSelector(
       CoordinatorRuleManager ruleManager,
       TieredBrokerConfig tierConfig,
-      ServerDiscoveryFactory serverDiscoveryFactory
+      ServerDiscoveryFactory serverDiscoveryFactory,
+      List<TieredBrokerSelectorStrategy> strategies
   )
   {
     this.ruleManager = ruleManager;
     this.tierConfig = tierConfig;
     this.serverDiscoveryFactory = serverDiscoveryFactory;
+    this.strategies = strategies;
   }
 
   @LifecycleStart
@@ -128,12 +131,12 @@ public class TieredBrokerHostSelector<T> implements HostSelector<T>
 
     String brokerServiceName = null;
 
-    // Somewhat janky way of always selecting highest priority broker for this type of query
-    if (query instanceof TimeBoundaryQuery) {
-      brokerServiceName = Iterables.getFirst(
-          tierConfig.getTierToBrokerMap().values(),
-          tierConfig.getDefaultBrokerServiceName()
-      );
+    for (TieredBrokerSelectorStrategy strategy : strategies) {
+      final Optional<String> optionalName = strategy.getBrokerServiceName(tierConfig, query);
+      if (optionalName.isPresent()) {
+        brokerServiceName = optionalName.get();
+        break;
+      }
     }
 
     if (brokerServiceName == null) {

server/src/main/java/io/druid/server/router/TieredBrokerSelectorStrategiesProvider.java

@@ -0,0 +1,59 @@
+/*
+ * 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.server.router;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.api.client.util.Lists;
+import com.google.common.base.Throwables;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+
+import java.util.List;
+
+/**
+ */
+public class TieredBrokerSelectorStrategiesProvider implements Provider<List<TieredBrokerSelectorStrategy>>
+{
+  private final List<TieredBrokerSelectorStrategy> strategies = Lists.newArrayList();
+
+  @Inject
+  public TieredBrokerSelectorStrategiesProvider(ObjectMapper jsonMapper, TieredBrokerConfig config)
+  {
+    try {
+      this.strategies.addAll(
+          (List<TieredBrokerSelectorStrategy>) jsonMapper.readValue(
+              config.getStrategies(), new TypeReference<List<TieredBrokerSelectorStrategy>>()
+          {
+          }
+          )
+      );
+    }
+    catch (Exception e) {
+      throw Throwables.propagate(e);
+    }
+  }
+
+  @Override
+  public List<TieredBrokerSelectorStrategy> get()
+  {
+    return strategies;
+  }
+}

server/src/main/java/io/druid/server/router/TieredBrokerSelectorStrategy.java

@@ -0,0 +1,19 @@
+package io.druid.server.router;
+
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.google.common.base.Optional;
+import io.druid.query.Query;
+
+/**
+ */
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type")
+@JsonSubTypes(value = {
+    @JsonSubTypes.Type(name = "timeBoundary", value = TimeBoundaryTieredBrokerSelectorStrategy.class),
+    @JsonSubTypes.Type(name = "priority", value = PriorityTieredBrokerSelectorStrategy.class)
+})
+
+public interface TieredBrokerSelectorStrategy
+{
+  public Optional<String> getBrokerServiceName(TieredBrokerConfig config, Query query);
+}

server/src/main/java/io/druid/server/router/TimeBoundaryTieredBrokerSelectorStrategy.java

@@ -0,0 +1,46 @@
+/*
+ * 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.server.router;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.Iterables;
+import io.druid.query.Query;
+import io.druid.query.timeboundary.TimeBoundaryQuery;
+
+/**
+ */
+public class TimeBoundaryTieredBrokerSelectorStrategy implements TieredBrokerSelectorStrategy
+{
+  @Override
+  public Optional<String> getBrokerServiceName(TieredBrokerConfig tierConfig, Query query)
+  {
+    // Somewhat janky way of always selecting highest priority broker for this type of query
+    if (query instanceof TimeBoundaryQuery) {
+      return Optional.of(
+          Iterables.getFirst(
+              tierConfig.getTierToBrokerMap().values(),
+              tierConfig.getDefaultBrokerServiceName()
+          )
+      );
+    }
+
+    return Optional.absent();
+  }
+}

server/src/test/java/io/druid/server/router/TieredBrokerHostSelectorTest.java

@@ -84,7 +84,8 @@ public class TieredBrokerHostSelectorTest
             return "hotBroker";
           }
         },
-        factory
+        factory,
+        Arrays.asList(new TimeBoundaryTieredBrokerSelectorStrategy(), new PriorityTieredBrokerSelectorStrategy())
     );
     EasyMock.expect(factory.createSelector(EasyMock.<String>anyObject())).andReturn(selector).atLeastOnce();
     EasyMock.replay(factory);
@@ -196,6 +197,30 @@ public class TieredBrokerHostSelectorTest
     Assert.assertEquals("coldBroker", brokerName);
   }
 
+  @Test
+    public void testPrioritySelect() throws Exception
+    {
+      String brokerName = (String) brokerSelector.select(
+          Druids.newTimeseriesQueryBuilder()
+                .dataSource("test")
+                .aggregators(Arrays.<AggregatorFactory>asList(new CountAggregatorFactory("count")))
+                .intervals(
+                    new MultipleIntervalSegmentSpec(
+                        Arrays.<Interval>asList(
+                            new Interval("2011-08-31/2011-09-01"),
+                            new Interval("2012-08-31/2012-09-01"),
+                            new Interval("2013-08-31/2013-09-01")
+                        )
+                    )
+                )
+                .context(ImmutableMap.<String, Object>of("priority", -1))
+                .build()
+      ).lhs;
+
+      Assert.assertEquals("hotBroker", brokerName);
+    }
+
+
   private static class TestRuleManager extends CoordinatorRuleManager
   {
     public TestRuleManager(

services/src/main/java/io/druid/cli/CliRouter.java

@@ -23,6 +23,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.inject.Binder;
 import com.google.inject.Module;
 import com.google.inject.Provides;
+import com.google.inject.TypeLiteral;
 import com.metamx.common.logger.Logger;
 import io.airlift.command.Command;
 import io.druid.client.RoutingDruidClient;
@@ -42,6 +43,8 @@ import io.druid.server.router.QueryHostFinder;
 import io.druid.server.router.Router;
 import io.druid.server.router.TieredBrokerConfig;
 import io.druid.server.router.TieredBrokerHostSelector;
+import io.druid.server.router.TieredBrokerSelectorStrategiesProvider;
+import io.druid.server.router.TieredBrokerSelectorStrategy;
 import org.eclipse.jetty.server.Server;
 
 import java.util.List;
@@ -79,6 +82,10 @@ public class CliRouter extends ServerRunnable
             binder.bind(TieredBrokerHostSelector.class).in(ManageLifecycle.class);
             binder.bind(QueryHostFinder.class).in(LazySingleton.class);
             binder.bind(RoutingDruidClient.class).in(LazySingleton.class);
+            binder.bind(new TypeLiteral<List<TieredBrokerSelectorStrategy>>(){})
+                      .toProvider(TieredBrokerSelectorStrategiesProvider.class)
+                      .in(LazySingleton.class);
+
 
             binder.bind(JettyServerInitializer.class).to(RouterJettyServerInitializer.class).in(LazySingleton.class);