Make 0.19 brokers compatible with 0.18 router (#10091)

* Make brokers backwards compatible

In 0.19, Brokers gained the ability to serve segments. To support this change,
a `BROKER` ServerType was added to `druid.server.coordination`.

Druid nodes prior to this change do not know of this new server type and so
they would fail to deserialize this node's announcement.

This change makes it so that the broker only announces itself if the segment
cache is configured on the broker. It is expected that a Druid admin will only
configure the segment cache on the broker once the cluster has been upgraded
to a version that supports a broker using the segment cache.

* make code nicer

* Add tests

* Ignore icode coverage for nitialization classes

* Revert "Ignore icode coverage for nitialization classes"

This reverts commit aeec0c2ac2.

* code review

server/src/main/java/org/apache/druid/discovery/DataNodeService.java

@@ -20,6 +20,7 @@
 package org.apache.druid.discovery;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import org.apache.druid.server.coordination.ServerType;
 
@@ -36,6 +37,7 @@ public class DataNodeService extends DruidService
   private final long maxSize;
   private final ServerType type;
   private final int priority;
+  private final boolean isDiscoverable;
 
   @JsonCreator
   public DataNodeService(
@@ -44,11 +46,23 @@ public class DataNodeService extends DruidService
       @JsonProperty("type") ServerType type,
       @JsonProperty("priority") int priority
   )
+  {
+    this(tier, maxSize, type, priority, true);
+  }
+
+  public DataNodeService(
+      String tier,
+      long maxSize,
+      ServerType type,
+      int priority,
+      boolean isDiscoverable
+  )
   {
     this.tier = tier;
     this.maxSize = maxSize;
     this.type = type;
     this.priority = priority;
+    this.isDiscoverable = isDiscoverable;
   }
 
   @Override
@@ -81,6 +95,13 @@ public class DataNodeService extends DruidService
     return priority;
   }
 
+  @Override
+  @JsonIgnore
+  public boolean isDiscoverable()
+  {
+    return isDiscoverable;
+  }
+
   @Override
   public boolean equals(Object o)
   {

server/src/main/java/org/apache/druid/discovery/DruidService.java

@@ -19,6 +19,7 @@
 
 package org.apache.druid.discovery;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonSubTypes;
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 
@@ -34,4 +35,17 @@ import com.fasterxml.jackson.annotation.JsonTypeInfo;
 public abstract class DruidService
 {
   public abstract String getName();
+
+  /**
+   * @return Whether the service should be discoverable. The default implementation returns true.
+   *
+   * Some implementations may choose to override this so that the service is not discoverable if it has not been
+   * configured. This will not throw a fatal exception, but instead will just skip binding and log a message. This could
+   * be useful for optional configuration for the service.
+   */
+  @JsonIgnore
+  public boolean isDiscoverable()
+  {
+    return true;
+  }
 }

server/src/main/java/org/apache/druid/guice/StorageNodeModule.java

@@ -19,19 +19,23 @@
 
 package org.apache.druid.guice;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.inject.Binder;
 import com.google.inject.Module;
 import com.google.inject.Provides;
 import com.google.inject.ProvisionException;
+import com.google.inject.name.Named;
 import com.google.inject.util.Providers;
 import org.apache.druid.client.DruidServerConfig;
 import org.apache.druid.discovery.DataNodeService;
 import org.apache.druid.guice.annotations.Self;
+import org.apache.druid.java.util.emitter.EmittingLogger;
 import org.apache.druid.query.DruidProcessingConfig;
 import org.apache.druid.segment.column.ColumnConfig;
 import org.apache.druid.segment.loading.SegmentLoaderConfig;
 import org.apache.druid.server.DruidNode;
 import org.apache.druid.server.coordination.DruidServerMetadata;
+import org.apache.druid.server.coordination.ServerType;
 
 import javax.annotation.Nullable;
 
@@ -39,6 +43,10 @@ import javax.annotation.Nullable;
  */
 public class StorageNodeModule implements Module
 {
+  private static final EmittingLogger log = new EmittingLogger(StorageNodeModule.class);
+  @VisibleForTesting
+  static final String IS_SEGMENT_CACHE_CONFIGURED = "IS_SEGMENT_CACHE_CONFIGURED";
+
   @Override
   public void configure(Binder binder)
   {
@@ -74,17 +82,39 @@ public class StorageNodeModule implements Module
 
   @Provides
   @LazySingleton
-  public DataNodeService getDataNodeService(@Nullable ServerTypeConfig serverTypeConfig, DruidServerConfig config)
+  public DataNodeService getDataNodeService(
+      @Nullable ServerTypeConfig serverTypeConfig,
+      DruidServerConfig config,
+      @Named(IS_SEGMENT_CACHE_CONFIGURED) Boolean isSegmentCacheConfigured
+  )
   {
     if (serverTypeConfig == null) {
-      throw new ProvisionException("Must override the binding for ServerTypeConfig if you want a DruidServerMetadata.");
+      throw new ProvisionException("Must override the binding for ServerTypeConfig if you want a DataNodeService.");
+    }
+    if (!isSegmentCacheConfigured) {
+      log.info(
+          "Segment cache not configured on ServerType [%s]. It will not be assignable for segment placement",
+          serverTypeConfig.getServerType()
+      );
+      if (ServerType.HISTORICAL.equals(serverTypeConfig.getServerType())) {
+        throw new ProvisionException("Segment cache locations must be set on historicals.");
+      }
     }
 
     return new DataNodeService(
         config.getTier(),
         config.getMaxSize(),
         serverTypeConfig.getServerType(),
-        config.getPriority()
+        config.getPriority(),
+        isSegmentCacheConfigured
     );
   }
+
+  @Provides
+  @LazySingleton
+  @Named(IS_SEGMENT_CACHE_CONFIGURED)
+  public Boolean isSegmentCacheConfigured(SegmentLoaderConfig segmentLoaderConfig)
+  {
+    return !segmentLoaderConfig.getLocations().isEmpty();
+  }
 }

server/src/main/java/org/apache/druid/server/coordination/SegmentLoadDropHandler.java

@@ -35,7 +35,6 @@ import com.google.common.util.concurrent.SettableFuture;
 import com.google.inject.Inject;
 import org.apache.druid.guice.ManageLifecycle;
 import org.apache.druid.guice.ServerTypeConfig;
-import org.apache.druid.java.util.common.IAE;
 import org.apache.druid.java.util.common.ISE;
 import org.apache.druid.java.util.common.concurrent.Execs;
 import org.apache.druid.java.util.common.lifecycle.LifecycleStart;
@@ -143,14 +142,6 @@ public class SegmentLoadDropHandler implements DataSegmentChangeHandler
 
     this.exec = exec;
     this.segmentsToDelete = new ConcurrentSkipListSet<>();
-
-    if (config.getLocations().isEmpty()) {
-      if (ServerType.HISTORICAL.equals(serverTypeConfig.getServerType())) {
-        throw new IAE("Segment cache locations must be set on historicals.");
-      } else {
-        log.info("Not starting SegmentLoadDropHandler with empty segment cache locations.");
-      }
-    }
     requestStatuses = CacheBuilder.newBuilder().maximumSize(config.getStatusQueueMaxSize()).initialCapacity(8).build();
   }
 

server/src/test/java/org/apache/druid/guice/StorageNodeModuleTest.java

@@ -0,0 +1,196 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.guice;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import com.google.inject.Key;
+import com.google.inject.ProvisionException;
+import com.google.inject.Scopes;
+import com.google.inject.name.Names;
+import com.google.inject.util.Modules;
+import org.apache.druid.discovery.DataNodeService;
+import org.apache.druid.guice.annotations.Self;
+import org.apache.druid.query.DruidProcessingConfig;
+import org.apache.druid.segment.loading.SegmentLoaderConfig;
+import org.apache.druid.segment.loading.StorageLocationConfig;
+import org.apache.druid.server.DruidNode;
+import org.apache.druid.server.coordination.DruidServerMetadata;
+import org.apache.druid.server.coordination.ServerType;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.mockito.Answers;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import javax.validation.Validation;
+import javax.validation.Validator;
+import java.util.Collections;
+
+@RunWith(MockitoJUnitRunner.class)
+public class StorageNodeModuleTest
+{
+  private static final boolean INJECT_SERVER_TYPE_CONFIG = true;
+
+  @Rule
+  public ExpectedException exceptionRule = ExpectedException.none();
+
+  @Mock(answer = Answers.RETURNS_MOCKS)
+  private ObjectMapper mapper;
+  @Mock(answer = Answers.RETURNS_MOCKS)
+  private DruidNode self;
+  @Mock(answer = Answers.RETURNS_MOCKS)
+  private ServerTypeConfig serverTypeConfig;
+  @Mock
+  private DruidProcessingConfig druidProcessingConfig;
+  @Mock
+  private SegmentLoaderConfig segmentLoaderConfig;
+  @Mock
+  private StorageLocationConfig storageLocation;
+
+  private Injector injector;
+  private StorageNodeModule target;
+
+  @Before
+  public void setUp()
+  {
+    Mockito.when(segmentLoaderConfig.getLocations()).thenReturn(Collections.singletonList(storageLocation));
+
+    target = new StorageNodeModule();
+    injector = makeInjector(INJECT_SERVER_TYPE_CONFIG);
+  }
+
+  @Test
+  public void testIsSegmentCacheConfiguredIsInjected()
+  {
+    Boolean isSegmentCacheConfigured = injector.getInstance(
+        Key.get(Boolean.class, Names.named(StorageNodeModule.IS_SEGMENT_CACHE_CONFIGURED))
+    );
+    Assert.assertNotNull(isSegmentCacheConfigured);
+    Assert.assertTrue(isSegmentCacheConfigured);
+  }
+
+  @Test
+  public void testIsSegmentCacheConfiguredWithNoLocationsConfiguredIsInjected()
+  {
+    mockSegmentCacheNotConfigured();
+    Boolean isSegmentCacheConfigured = injector.getInstance(
+        Key.get(Boolean.class, Names.named(StorageNodeModule.IS_SEGMENT_CACHE_CONFIGURED))
+    );
+    Assert.assertNotNull(isSegmentCacheConfigured);
+    Assert.assertFalse(isSegmentCacheConfigured);
+  }
+
+  @Test
+  public void getDataNodeServiceWithNoServerTypeConfigShouldThrowProvisionException()
+  {
+    exceptionRule.expect(ProvisionException.class);
+    exceptionRule.expectMessage("Must override the binding for ServerTypeConfig if you want a DataNodeService.");
+    injector = makeInjector(!INJECT_SERVER_TYPE_CONFIG);
+    injector.getInstance(DataNodeService.class);
+  }
+
+  @Test
+  public void getDataNodeServiceWithNoSegmentCacheConfiguredThrowProvisionException()
+  {
+    exceptionRule.expect(ProvisionException.class);
+    exceptionRule.expectMessage("Segment cache locations must be set on historicals.");
+    Mockito.doReturn(ServerType.HISTORICAL).when(serverTypeConfig).getServerType();
+    mockSegmentCacheNotConfigured();
+    injector.getInstance(DataNodeService.class);
+  }
+
+  @Test
+  public void getDataNodeServiceIsInjectedAsSingleton()
+  {
+    DataNodeService dataNodeService = injector.getInstance(DataNodeService.class);
+    Assert.assertNotNull(dataNodeService);
+    DataNodeService other = injector.getInstance(DataNodeService.class);
+    Assert.assertSame(dataNodeService, other);
+  }
+
+  @Test
+  public void getDataNodeServiceIsInjectedAndDiscoverable()
+  {
+    DataNodeService dataNodeService = injector.getInstance(DataNodeService.class);
+    Assert.assertNotNull(dataNodeService);
+    Assert.assertTrue(dataNodeService.isDiscoverable());
+  }
+
+  @Test
+  public void getDataNodeServiceWithSegmentCacheNotConfiguredIsInjectedAndDiscoverable()
+  {
+    mockSegmentCacheNotConfigured();
+    DataNodeService dataNodeService = injector.getInstance(DataNodeService.class);
+    Assert.assertNotNull(dataNodeService);
+    Assert.assertFalse(dataNodeService.isDiscoverable());
+  }
+
+  @Test
+  public void testDruidServerMetadataIsInjectedAsSingleton()
+  {
+    DruidServerMetadata druidServerMetadata = injector.getInstance(DruidServerMetadata.class);
+    Assert.assertNotNull(druidServerMetadata);
+    DruidServerMetadata other = injector.getInstance(DruidServerMetadata.class);
+    Assert.assertSame(druidServerMetadata, other);
+  }
+
+  @Test
+  public void testDruidServerMetadataWithNoServerTypeConfigShouldThrowProvisionException()
+  {
+    exceptionRule.expect(ProvisionException.class);
+    exceptionRule.expectMessage("Must override the binding for ServerTypeConfig if you want a DruidServerMetadata.");
+    injector = makeInjector(!INJECT_SERVER_TYPE_CONFIG);
+    injector.getInstance(DruidServerMetadata.class);
+  }
+
+  private Injector makeInjector(boolean withServerTypeConfig)
+  {
+    return Guice.createInjector(
+        Modules.override(
+            (binder) -> {
+              binder.bind(DruidNode.class).annotatedWith(Self.class).toInstance(self);
+              binder.bind(Validator.class).toInstance(Validation.buildDefaultValidatorFactory().getValidator());
+              binder.bind(DruidProcessingConfig.class).toInstance(druidProcessingConfig);
+              binder.bindScope(LazySingleton.class, Scopes.SINGLETON);
+            },
+            target
+        ).with(
+            (binder) -> {
+              binder.bind(SegmentLoaderConfig.class).toInstance(segmentLoaderConfig);
+              if (withServerTypeConfig) {
+                binder.bind(ServerTypeConfig.class).toInstance(serverTypeConfig);
+              }
+            }
+        )
+    );
+  }
+
+  private void mockSegmentCacheNotConfigured()
+  {
+    Mockito.doReturn(Collections.emptyList()).when(segmentLoaderConfig).getLocations();
+  }
+}

server/src/test/java/org/apache/druid/server/coordination/SegmentLoadDropHandlerTest.java

@@ -25,7 +25,6 @@ import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.common.util.concurrent.ListenableFuture;
 import org.apache.druid.guice.ServerTypeConfig;
-import org.apache.druid.java.util.common.IAE;
 import org.apache.druid.java.util.common.Intervals;
 import org.apache.druid.java.util.common.concurrent.Execs;
 import org.apache.druid.java.util.common.concurrent.ScheduledExecutorFactory;
@@ -276,40 +275,6 @@ public class SegmentLoadDropHandlerTest
     segmentLoadDropHandler.stop();
   }
 
-  @Test
-  public void testSegmentLoading1BrokerWithNoLocations() throws Exception
-  {
-    SegmentLoadDropHandler segmentLoadDropHandlerBrokerWithNoLocations = new SegmentLoadDropHandler(
-        jsonMapper,
-        segmentLoaderConfigNoLocations,
-        announcer,
-        EasyMock.createNiceMock(DataSegmentServerAnnouncer.class),
-        segmentManager,
-        scheduledExecutorFactory.create(5, "SegmentLoadDropHandlerTest-brokerNoLocations-[%d]"),
-        new ServerTypeConfig(ServerType.BROKER)
-    );
-
-    segmentLoadDropHandlerBrokerWithNoLocations.start();
-    segmentLoadDropHandler.stop();
-  }
-
-  @Test
-  public void testSegmentLoading1HistoricalWithNoLocations()
-  {
-    expectedException.expect(IAE.class);
-    expectedException.expectMessage("Segment cache locations must be set on historicals.");
-
-    new SegmentLoadDropHandler(
-        jsonMapper,
-        segmentLoaderConfigNoLocations,
-        announcer,
-        EasyMock.createNiceMock(DataSegmentServerAnnouncer.class),
-        segmentManager,
-        scheduledExecutorFactory.create(5, "SegmentLoadDropHandlerTest-[%d]"),
-        new ServerTypeConfig(ServerType.HISTORICAL)
-    );
-  }
-
   /**
    * Steps:
    * 1. addSegment() succesfully loads the segment and annouces it

services/pom.xml

@@ -166,6 +166,11 @@
             <artifactId>junit</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.hamcrest</groupId>
             <artifactId>hamcrest-core</artifactId>

services/src/main/java/org/apache/druid/cli/ServerRunnable.java

@@ -19,6 +19,7 @@
 
 package org.apache.druid.cli;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.inject.Binder;
@@ -37,6 +38,7 @@ import org.apache.druid.guice.LifecycleModule;
 import org.apache.druid.guice.annotations.Self;
 import org.apache.druid.java.util.common.lifecycle.Lifecycle;
 import org.apache.druid.java.util.common.logger.Logger;
+import org.apache.druid.java.util.emitter.EmittingLogger;
 import org.apache.druid.server.DruidNode;
 
 import java.lang.annotation.Annotation;
@@ -47,6 +49,8 @@ import java.util.List;
  */
 public abstract class ServerRunnable extends GuiceRunnable
 {
+  private static final EmittingLogger log = new EmittingLogger(ServerRunnable.class);
+
   public ServerRunnable(Logger log)
   {
     super(log);
@@ -154,7 +158,11 @@ public abstract class ServerRunnable extends GuiceRunnable
 
       public DiscoverySideEffectsProvider build()
       {
-        return new DiscoverySideEffectsProvider(nodeRole, serviceClasses, useLegacyAnnouncer);
+        return new DiscoverySideEffectsProvider(
+            nodeRole,
+            serviceClasses,
+            useLegacyAnnouncer
+        );
       }
     }
 
@@ -194,15 +202,43 @@ public abstract class ServerRunnable extends GuiceRunnable
       this.useLegacyAnnouncer = useLegacyAnnouncer;
     }
 
+    @VisibleForTesting
+    DiscoverySideEffectsProvider(
+        final NodeRole nodeRole,
+        final List<Class<? extends DruidService>> serviceClasses,
+        final boolean useLegacyAnnouncer,
+        final DruidNode druidNode,
+        final DruidNodeAnnouncer announcer,
+        final ServiceAnnouncer legacyAnnouncer,
+        final Lifecycle lifecycle,
+        final Injector injector
+    )
+    {
+      this.nodeRole = nodeRole;
+      this.serviceClasses = serviceClasses;
+      this.useLegacyAnnouncer = useLegacyAnnouncer;
+      this.druidNode = druidNode;
+      this.announcer = announcer;
+      this.legacyAnnouncer = legacyAnnouncer;
+      this.lifecycle = lifecycle;
+      this.injector = injector;
+    }
+
     @Override
     public Child get()
     {
       ImmutableMap.Builder<String, DruidService> builder = new ImmutableMap.Builder<>();
       for (Class<? extends DruidService> clazz : serviceClasses) {
         DruidService service = injector.getInstance(clazz);
-        builder.put(service.getName(), service);
+        if (service.isDiscoverable()) {
+          builder.put(service.getName(), service);
+        } else {
+          log.info(
+              "Service[%s] is not discoverable. This will not be listed as a service provided by this node.",
+              service.getName()
+          );
+        }
       }
-
       DiscoveryDruidNode discoveryDruidNode = new DiscoveryDruidNode(druidNode, nodeRole, builder.build());
 
       lifecycle.addHandler(
@@ -232,7 +268,6 @@ public abstract class ServerRunnable extends GuiceRunnable
           },
           Lifecycle.Stage.ANNOUNCEMENTS
       );
-
       return new Child();
     }
   }

services/src/test/java/org/apache/druid/cli/DiscoverySideEffectsProviderTest.java

@@ -0,0 +1,142 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.cli;
+
+import com.google.common.collect.ImmutableList;
+import com.google.inject.Injector;
+import org.apache.druid.curator.discovery.ServiceAnnouncer;
+import org.apache.druid.discovery.DiscoveryDruidNode;
+import org.apache.druid.discovery.DruidNodeAnnouncer;
+import org.apache.druid.discovery.DruidService;
+import org.apache.druid.discovery.NodeRole;
+import org.apache.druid.java.util.common.lifecycle.Lifecycle;
+import org.apache.druid.server.DruidNode;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentMatchers;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@RunWith(MockitoJUnitRunner.class)
+public class DiscoverySideEffectsProviderTest
+{
+  private static final boolean USE_LEGACY_ANNOUNCER = true;
+
+  private NodeRole nodeRole;
+  @Mock
+  private DruidNode druidNode;
+  /**
+   * This announcer is mocked to fail if it tries to announce a Druid service that is not discoverable.
+   */
+  @Mock
+  private DruidNodeAnnouncer discoverableOnlyAnnouncer;
+  @Mock
+  private ServiceAnnouncer legacyAnnouncer;
+  @Mock
+  private Lifecycle lifecycle;
+  @Mock
+  private Injector injector;
+  private List<Lifecycle.Handler> lifecycleHandlers;
+
+  private ServerRunnable.DiscoverySideEffectsProvider target;
+
+  @Before
+  public void setUp()
+  {
+    nodeRole = NodeRole.HISTORICAL;
+    lifecycleHandlers = new ArrayList<>();
+    Mockito.when(injector.getInstance(DiscoverableDruidService.class)).thenReturn(new DiscoverableDruidService());
+    Mockito.when(injector.getInstance(UnDiscoverableDruidService.class)).thenReturn(new UnDiscoverableDruidService());
+    Mockito.doAnswer((invocation) -> {
+      DiscoveryDruidNode discoveryDruidNode = invocation.getArgument(0);
+      boolean isAllServicesDiscoverable =
+          discoveryDruidNode.getServices().values().stream().allMatch(DruidService::isDiscoverable);
+      Assert.assertTrue(isAllServicesDiscoverable);
+      return null;
+    }).when(discoverableOnlyAnnouncer).announce(ArgumentMatchers.any(DiscoveryDruidNode.class));
+    Mockito.doAnswer((invocation) -> lifecycleHandlers.add(invocation.getArgument(0)))
+           .when(lifecycle).addHandler(
+        ArgumentMatchers.any(Lifecycle.Handler.class),
+        ArgumentMatchers.eq(Lifecycle.Stage.ANNOUNCEMENTS)
+      );
+    target = new ServerRunnable.DiscoverySideEffectsProvider(
+        nodeRole,
+        ImmutableList.of(DiscoverableDruidService.class, UnDiscoverableDruidService.class),
+        USE_LEGACY_ANNOUNCER,
+        druidNode,
+        discoverableOnlyAnnouncer,
+        legacyAnnouncer,
+        lifecycle,
+        injector
+    );
+  }
+
+  @Test
+  public void testGetShouldAddAnnouncementsForDiscoverableServices() throws Exception
+  {
+    ServerRunnable.DiscoverySideEffectsProvider.Child child = target.get();
+    Assert.assertNotNull(child);
+    Assert.assertEquals(1, lifecycleHandlers.size());
+    // Start the lifecycle handler. This will make announcements via the announcer
+    lifecycleHandlers.get(0).start();
+  }
+
+  /**
+   * Dummy service which is discoverable.
+   */
+  private static class DiscoverableDruidService extends DruidService
+  {
+    @Override
+    public String getName()
+    {
+      return "DiscoverableDruidService";
+    }
+
+    @Override
+    public boolean isDiscoverable()
+    {
+      return true;
+    }
+  }
+
+  /**
+   * Dummy service which is not discoverable.
+   */
+  private static class UnDiscoverableDruidService extends DruidService
+  {
+    @Override
+    public String getName()
+    {
+      return "UnDiscoverableDruidService";
+    }
+
+    @Override
+    public boolean isDiscoverable()
+    {
+      return false;
+    }
+  }
+}