Make CacheScheduler a singleton (#4293)

extensions-core/lookups-cached-global/src/main/java/io/druid/query/lookup/NamespaceLookupExtractorFactory.java

@@ -232,4 +232,10 @@ public class NamespaceLookupExtractorFactory implements LookupExtractorFactory
       readLock.unlock();
     }
   }
+
+  @VisibleForTesting
+  CacheScheduler getCacheScheduler()
+  {
+    return cacheScheduler;
+  }
 }

extensions-core/lookups-cached-global/src/main/java/io/druid/server/lookup/namespace/cache/CacheScheduler.java

@@ -24,6 +24,7 @@ import com.google.common.base.Throwables;
 import com.google.inject.Inject;
 import com.metamx.emitter.service.ServiceEmitter;
 import com.metamx.emitter.service.ServiceMetricEvent;
+import io.druid.guice.LazySingleton;
 import io.druid.java.util.common.ISE;
 import io.druid.java.util.common.logger.Logger;
 import io.druid.query.lookup.namespace.ExtractionNamespace;
@@ -60,6 +61,7 @@ import java.util.concurrent.atomic.AtomicReference;
  * entry.close(); // close the last VersionedCache and unschedule future updates
  * }</pre>
  */
+@LazySingleton
 public final class CacheScheduler
 {
   private static final Logger log = new Logger(CacheScheduler.class);

extensions-core/lookups-cached-global/src/test/java/io/druid/query/lookup/NamespaceLookupExtractorFactoryTest.java

@@ -31,7 +31,6 @@ import com.google.inject.Binder;
 import com.google.inject.Injector;
 import com.google.inject.Key;
 import com.google.inject.Module;
-
 import io.druid.guice.GuiceInjectors;
 import io.druid.guice.JsonConfigProvider;
 import io.druid.guice.annotations.Json;
@@ -42,8 +41,8 @@ import io.druid.java.util.common.ISE;
 import io.druid.query.lookup.namespace.ExtractionNamespace;
 import io.druid.query.lookup.namespace.URIExtractionNamespace;
 import io.druid.server.DruidNode;
-import io.druid.server.lookup.namespace.cache.NamespaceExtractionCacheManager;
 import io.druid.server.lookup.namespace.cache.CacheScheduler;
+import io.druid.server.lookup.namespace.cache.NamespaceExtractionCacheManager;
 import org.easymock.EasyMock;
 import org.easymock.IExpectationSetters;
 import org.joda.time.Period;
@@ -440,21 +439,7 @@ public class NamespaceLookupExtractorFactoryTest
   @Test
   public void testSerDe() throws Exception
   {
-    final Injector injector = Initialization.makeInjectorWithModules(
+    final Injector injector = makeInjector();
-        GuiceInjectors.makeStartupInjector(),
-        ImmutableList.of(
-            new Module()
-            {
-              @Override
-              public void configure(Binder binder)
-              {
-                JsonConfigProvider.bindInstance(
-                    binder, Key.get(DruidNode.class, Self.class), new DruidNode("test-inject", null, null)
-                );
-              }
-            }
-        )
-    );
     final ObjectMapper mapper = injector.getInstance(Key.get(ObjectMapper.class, Json.class));
     mapper.registerSubtypes(NamespaceLookupExtractorFactory.class);
     final String str = "{ \"type\": \"cachedNamespace\", \"extractionNamespace\": { \"type\": \"uri\", \"uriPrefix\": \"s3://bucket/prefix/\", \"fileRegex\": \"foo.*\\\\.gz\", \"namespaceParseSpec\": { \"format\": \"customJson\", \"keyFieldName\": \"someKey\", \"valueFieldName\": \"someVal\" }, \"pollPeriod\": \"PT5M\" } } }";
@@ -484,21 +469,7 @@ public class NamespaceLookupExtractorFactoryTest
   @Test
   public void testSimpleIntrospectionHandler() throws Exception
   {
-    final Injector injector = Initialization.makeInjectorWithModules(
+    final Injector injector = makeInjector();
-        GuiceInjectors.makeStartupInjector(),
-        ImmutableList.of(
-            new Module()
-            {
-              @Override
-              public void configure(Binder binder)
-              {
-                JsonConfigProvider.bindInstance(
-                    binder, Key.get(DruidNode.class, Self.class), new DruidNode("test-inject", null, null)
-                );
-              }
-            }
-        )
-    );
     final ObjectMapper mapper = injector.getInstance(Key.get(ObjectMapper.class, Json.class));
     mapper.registerSubtypes(NamespaceLookupExtractorFactory.class);
     final String str = "{ \"type\": \"cachedNamespace\", \"extractionNamespace\": { \"type\": \"staticMap\", \"map\": {\"foo\":\"bar\"} }, \"firstCacheTimeout\":10000 }";
@@ -524,6 +495,40 @@ public class NamespaceLookupExtractorFactoryTest
     }
   }
 
+  @Test
+  public void testSingletonCacheScheduler() throws Exception
+  {
+    final Injector injector = makeInjector();
+    final ObjectMapper mapper = injector.getInstance(Key.get(ObjectMapper.class, Json.class));
+    mapper.registerSubtypes(NamespaceLookupExtractorFactory.class);
+    final String str1 = "{ \"type\": \"cachedNamespace\", \"extractionNamespace\": { \"type\": \"staticMap\", \"map\": {\"foo\":\"bar\"} }, \"firstCacheTimeout\":10000 }";
+    final NamespaceLookupExtractorFactory factory1 =
+        (NamespaceLookupExtractorFactory) mapper.readValue(str1, LookupExtractorFactory.class);
+    final String str2 = "{ \"type\": \"cachedNamespace\", \"extractionNamespace\": { \"type\": \"uri\", \"uriPrefix\": \"s3://bucket/prefix/\", \"fileRegex\": \"foo.*\\\\.gz\", \"namespaceParseSpec\": { \"format\": \"customJson\", \"keyFieldName\": \"someKey\", \"valueFieldName\": \"someVal\" }, \"pollPeriod\": \"PT5M\" } } }";
+    final NamespaceLookupExtractorFactory factory2 =
+        (NamespaceLookupExtractorFactory) mapper.readValue(str2, LookupExtractorFactory.class);
+    Assert.assertTrue(factory1.getCacheScheduler() == factory2.getCacheScheduler());
+  }
+
+  private Injector makeInjector()
+  {
+    return Initialization.makeInjectorWithModules(
+        GuiceInjectors.makeStartupInjector(),
+        ImmutableList.of(
+            new Module()
+            {
+              @Override
+              public void configure(Binder binder)
+              {
+                JsonConfigProvider.bindInstance(
+                    binder, Key.get(DruidNode.class, Self.class), new DruidNode("test-inject", null, null)
+                );
+              }
+            }
+        )
+    );
+  }
+
   @Test
   public void testExceptionalIntrospectionHandler() throws Exception
   {