HSEARCH-2945 Update mass indexer monitor configuration

documentation/src/main/asciidoc/migration/index.adoc

@@ -95,6 +95,10 @@ But there are next changes:
 This was done to address the scenarios where the total number of identifiers to load is not known ahead of time.
 - Deprecated `org.hibernate.search.mapper.orm.massindexing.MassIndexingFailureHandler`, `org.hibernate.search.mapper.orm.massindexing.MassIndexingMonitor`
 interfaces are removed in this version. They have their alternatives in a `org.hibernate.search.mapper.pojo.massindexing` for a while now.
+- `org.hibernate.search.mapper.pojo.massindexing.MassIndexingMonitor#addToTotalCount(..)` gets deprecated for removal.
+Instead, we are introducing the `org.hibernate.search.mapper.pojo.massindexing.MassIndexingTypeGroupMonitor`
+that can be obtained through `org.hibernate.search.mapper.pojo.massindexing.MassIndexingMonitor#typeGroupMonitor(..)`.
+This new type group monitor has more flexibility and also allows implementors to skip total count computations if needed.
 
 [[spi]]
 == SPI

documentation/src/main/asciidoc/public/reference/_indexing-massindexer.adoc

@@ -318,6 +318,9 @@ The default, built-in monitor logs progress periodically at the `INFO` level,
 but a custom monitor can be set by implementing the `MassIndexingMonitor` interface
 and passing an instance using the `monitor` method.
 
+The built-in monitor's behaviour can be customized through `DefaultMassIndexingMonitor` builder,
+e.g. `indexer.monitor( DefaultMassIndexingMonitor.builder().countOnStart( false ).build() ) )`
+
 Implementations of `MassIndexingMonitor` must be thread-safe.
 
 |`failureHandler(MassIndexingFailureHandler)`

integrationtest/mapper/orm/src/test/java/org/hibernate/search/integrationtest/mapper/orm/massindexing/MassIndexingMonitorIT.java

@@ -167,6 +167,7 @@ public String getAuthor() {
 		}
 	}
 
+	@SuppressWarnings("removal")
 	public static class StaticCountersMonitor implements MassIndexingMonitor {
 
 		public static StaticCounters.Key ADDED = StaticCounters.createKey();

integrationtest/mapper/pojo-base/src/test/java/org/hibernate/search/integrationtest/mapper/pojo/massindexing/MassIndexingDefaultMonitorIT.java

@@ -0,0 +1,208 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.search.integrationtest.mapper.pojo.massindexing;
+
+import static org.assertj.core.api.Fail.fail;
+
+import java.lang.invoke.MethodHandles;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
+
+import org.hibernate.search.engine.backend.work.execution.DocumentCommitStrategy;
+import org.hibernate.search.engine.backend.work.execution.DocumentRefreshStrategy;
+import org.hibernate.search.integrationtest.mapper.pojo.testsupport.loading.PersistenceTypeKey;
+import org.hibernate.search.integrationtest.mapper.pojo.testsupport.loading.StubEntityLoadingBinder;
+import org.hibernate.search.integrationtest.mapper.pojo.testsupport.loading.StubLoadingContext;
+import org.hibernate.search.mapper.pojo.loading.mapping.annotation.EntityLoadingBinderRef;
+import org.hibernate.search.mapper.pojo.mapping.definition.annotation.DocumentId;
+import org.hibernate.search.mapper.pojo.mapping.definition.annotation.GenericField;
+import org.hibernate.search.mapper.pojo.mapping.definition.annotation.Indexed;
+import org.hibernate.search.mapper.pojo.mapping.definition.annotation.SearchEntity;
+import org.hibernate.search.mapper.pojo.massindexing.DefaultMassIndexingMonitor;
+import org.hibernate.search.mapper.pojo.standalone.mapping.SearchMapping;
+import org.hibernate.search.mapper.pojo.standalone.massindexing.MassIndexer;
+import org.hibernate.search.mapper.pojo.standalone.session.SearchSession;
+import org.hibernate.search.util.impl.integrationtest.common.extension.BackendMock;
+import org.hibernate.search.util.impl.integrationtest.mapper.pojo.standalone.StandalonePojoMappingSetupHelper;
+import org.hibernate.search.util.impl.test.extension.ExpectedLog4jLog;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import org.apache.logging.log4j.Level;
+
+class MassIndexingDefaultMonitorIT {
+
+	private static final int COUNT = 100;
+	@RegisterExtension
+	public final BackendMock backendMock = BackendMock.create();
+
+	@RegisterExtension
+	public final StandalonePojoMappingSetupHelper setupHelper =
+			StandalonePojoMappingSetupHelper.withBackendMock( MethodHandles.lookup(), backendMock );
+
+	@RegisterExtension
+	public ExpectedLog4jLog logged = ExpectedLog4jLog.create();
+
+	private final StubLoadingContext loadingContext = new StubLoadingContext();
+
+	@ValueSource(booleans = { true, false })
+	@ParameterizedTest
+	void countOnBeforeType(boolean doCounts) {
+		actualTest( () -> {
+			logged.expectEvent( Level.INFO, "Mass indexing complete in ", ". Indexed 100/100 entities" );
+			if ( doCounts ) {
+				logged.expectEvent( Level.INFO, "Mass indexing is going to index 100 entities" ).once();
+			}
+			else {
+				logged.expectEvent( Level.INFO, "Mass indexing is going to index 100 entities" ).never();
+			}
+		}, indexer -> indexer.monitor( DefaultMassIndexingMonitor.builder().countOnBeforeType( doCounts ).build() ) );
+	}
+
+	@ValueSource(booleans = { true, false })
+	@ParameterizedTest
+	void countOnStart(boolean doCounts) {
+		actualTest( () -> {
+			logged.expectEvent( Level.INFO, "Mass indexing complete in ", ". Indexed 100/100 entities" );
+			logged.expectEvent( Level.INFO, "Mass indexing is going to index 100 entities" ).once();
+			if ( doCounts ) {
+				logged.expectEvent( Level.INFO,
+						"Mass indexing is going to index approx. 100 entities ([ Book ]). Actual number may change once the indexing starts." )
+						.once();
+			}
+			else {
+				logged.expectEvent( Level.INFO,
+						"Mass indexing is going to index approx. 100 entities ([ Book ]). Actual number may change once the indexing starts." )
+						.never();
+			}
+		}, indexer -> indexer.monitor( DefaultMassIndexingMonitor.builder().countOnStart( doCounts ).build() ) );
+	}
+
+	@Test
+	void noCountsAtAll() {
+		actualTest( () -> {
+			logged.expectEvent( Level.INFO, "Mass indexing complete in ", ". Indexed 100/100 entities" ).once();
+			logged.expectEvent( Level.INFO, "Mass indexing is going to index 100 entities" ).never();
+			logged.expectEvent( Level.INFO,
+					"Mass indexing is going to index approx. 100 entities ([ Book ]). Actual number may change once the indexing starts." )
+					.never();
+		}, indexer -> indexer
+				.monitor( DefaultMassIndexingMonitor.builder().countOnStart( false ).countOnBeforeType( false ).build() ) );
+	}
+
+	private void actualTest(Runnable expectedLogs, Consumer<MassIndexer> massIndexerConfiguration) {
+		backendMock.expectAnySchema( Book.NAME );
+
+		SearchMapping mapping = setupHelper.start()
+				.expectCustomBeans()
+				.setup( Book.class );
+
+		backendMock.verifyExpectationsMet();
+
+		initData();
+
+		expectedLogs.run();
+
+		try ( SearchSession searchSession = mapping.createSession() ) {
+			MassIndexer indexer = searchSession.massIndexer()
+					// Simulate passing information to connect to a DB, ...
+					.context( StubLoadingContext.class, loadingContext );
+
+			CompletableFuture<?> indexingFuture = new CompletableFuture<>();
+			indexingFuture.completeExceptionally( new SimulatedFailure( "Indexing error" ) );
+
+			// add operations on indexes can follow any random order,
+			// since they are executed by different threads
+			BackendMock.DocumentWorkCallListContext expectWorks = backendMock.expectWorks(
+					Book.NAME, DocumentCommitStrategy.NONE, DocumentRefreshStrategy.NONE
+			);
+			for ( int i = 0; i < COUNT; i++ ) {
+				final String id = Integer.toString( i );
+				expectWorks
+						.add( id, b -> b
+								.field( "title", "TITLE_" + id )
+								.field( "author", "AUTHOR_" + id )
+						);
+			}
+
+			// purgeAtStart and mergeSegmentsAfterPurge are enabled by default,
+			// so we expect 1 purge, 1 mergeSegments and 1 flush calls in this order:
+			backendMock.expectIndexScaleWorks( Book.NAME, searchSession.tenantIdentifierValue() )
+					.purge()
+					.mergeSegments()
+					.flush()
+					.refresh();
+
+			try {
+				massIndexerConfiguration.accept( indexer );
+				indexer.startAndWait();
+			}
+			catch (InterruptedException e) {
+				fail( "Unexpected InterruptedException: " + e.getMessage() );
+			}
+		}
+
+		backendMock.verifyExpectationsMet();
+	}
+
+	private void initData() {
+		for ( int i = 0; i < COUNT; i++ ) {
+			persist( new Book( i, "TITLE_" + i, "AUTHOR_" + i ) );
+		}
+	}
+
+	private void persist(Book book) {
+		loadingContext.persistenceMap( Book.PERSISTENCE_KEY ).put( book.id, book );
+	}
+
+	@SearchEntity(name = Book.NAME,
+			loadingBinder = @EntityLoadingBinderRef(type = StubEntityLoadingBinder.class))
+	@Indexed(index = Book.NAME)
+	public static class Book {
+
+		public static final String NAME = "Book";
+		public static final PersistenceTypeKey<Book, Integer> PERSISTENCE_KEY =
+				new PersistenceTypeKey<>( Book.class, Integer.class );
+
+		@DocumentId
+		private Integer id;
+
+		@GenericField
+		private String title;
+
+		@GenericField
+		private String author;
+
+		public Book() {
+		}
+
+		public Book(Integer id, String title, String author) {
+			this.id = id;
+			this.title = title;
+			this.author = author;
+		}
+
+		public Integer getId() {
+			return id;
+		}
+
+		public String getTitle() {
+			return title;
+		}
+
+		public String getAuthor() {
+			return author;
+		}
+	}
+
+	private static class SimulatedFailure extends RuntimeException {
+		SimulatedFailure(String message) {
+			super( message );
+		}
+	}
+}

integrationtest/mapper/pojo-base/src/test/java/org/hibernate/search/integrationtest/mapper/pojo/massindexing/MassIndexingMonitorIT.java

@@ -22,6 +22,9 @@
 import org.hibernate.search.mapper.pojo.mapping.definition.annotation.Indexed;
 import org.hibernate.search.mapper.pojo.mapping.definition.annotation.SearchEntity;
 import org.hibernate.search.mapper.pojo.massindexing.MassIndexingMonitor;
+import org.hibernate.search.mapper.pojo.massindexing.MassIndexingTypeGroupMonitor;
+import org.hibernate.search.mapper.pojo.massindexing.MassIndexingTypeGroupMonitorContext;
+import org.hibernate.search.mapper.pojo.massindexing.MassIndexingTypeGroupMonitorCreateContext;
 import org.hibernate.search.mapper.pojo.standalone.mapping.SearchMapping;
 import org.hibernate.search.mapper.pojo.standalone.massindexing.MassIndexer;
 import org.hibernate.search.mapper.pojo.standalone.session.SearchSession;
@@ -128,6 +131,66 @@ void simple() {
 		assertThat( staticCounters.get( StaticCountersMonitor.INDEXING_COMPLETED ) ).isEqualTo( 1 );
 	}
 
+	@Test
+	void skipTotalCount() {
+		SearchMapping mapping = setup( null );
+
+		try ( SearchSession searchSession = mapping.createSession() ) {
+			MassIndexer indexer = searchSession.massIndexer()
+					// Simulate passing information to connect to a DB, ...
+					.context( StubLoadingContext.class, loadingContext );
+
+			CompletableFuture<?> indexingFuture = new CompletableFuture<>();
+			indexingFuture.completeExceptionally( new SimulatedFailure( "Indexing error" ) );
+
+			// add operations on indexes can follow any random order,
+			// since they are executed by different threads
+			backendMock.expectWorks(
+					Book.NAME, DocumentCommitStrategy.NONE, DocumentRefreshStrategy.NONE
+			)
+					.add( "1", b -> b
+							.field( "title", TITLE_1 )
+							.field( "author", AUTHOR_1 )
+					)
+					.add( "3", b -> b
+							.field( "title", TITLE_3 )
+							.field( "author", AUTHOR_3 )
+					)
+					.createAndExecuteFollowingWorks( indexingFuture )
+					.add( "2", b -> b
+							.field( "title", TITLE_2 )
+							.field( "author", AUTHOR_2 )
+					);
+
+			// purgeAtStart and mergeSegmentsAfterPurge are enabled by default,
+			// so we expect 1 purge, 1 mergeSegments and 1 flush calls in this order:
+			backendMock.expectIndexScaleWorks( Book.NAME, searchSession.tenantIdentifierValue() )
+					.purge()
+					.mergeSegments()
+					.flush()
+					.refresh();
+
+			try {
+				indexer.monitor( new StaticCountersMonitor( false ) )
+						.startAndWait();
+			}
+			catch (SearchException ignored) {
+				// Expected, but not relevant to this test
+			}
+			catch (InterruptedException e) {
+				fail( "Unexpected InterruptedException: " + e.getMessage() );
+			}
+		}
+
+		backendMock.verifyExpectationsMet();
+
+		assertThat( staticCounters.get( StaticCountersMonitor.LOADED ) ).isEqualTo( 3 );
+		assertThat( staticCounters.get( StaticCountersMonitor.BUILT ) ).isEqualTo( 3 );
+		assertThat( staticCounters.get( StaticCountersMonitor.ADDED ) ).isEqualTo( 2 );
+		assertThat( staticCounters.get( StaticCountersMonitor.TOTAL ) ).isEqualTo( 0 );
+		assertThat( staticCounters.get( StaticCountersMonitor.INDEXING_COMPLETED ) ).isEqualTo( 1 );
+	}
+
 	private void initData() {
 		persist( new Book( 1, TITLE_1, AUTHOR_1 ) );
 		persist( new Book( 2, TITLE_2, AUTHOR_2 ) );
@@ -178,6 +241,7 @@ public String getAuthor() {
 		}
 	}
 
+	@SuppressWarnings("removal")
 	public static class StaticCountersMonitor implements MassIndexingMonitor {
 
 		public static StaticCounters.Key ADDED = StaticCounters.createKey();
@@ -186,6 +250,42 @@ public static class StaticCountersMonitor implements MassIndexingMonitor {
 		public static StaticCounters.Key TOTAL = StaticCounters.createKey();
 		public static StaticCounters.Key INDEXING_COMPLETED = StaticCounters.createKey();
 
+
+		private final boolean requiresTotalCount;
+
+		public StaticCountersMonitor() {
+			this( true );
+		}
+
+		public StaticCountersMonitor(boolean requiresTotalCount) {
+			this.requiresTotalCount = requiresTotalCount;
+		}
+
+		@Override
+		public MassIndexingTypeGroupMonitor typeGroupMonitor(MassIndexingTypeGroupMonitorCreateContext context) {
+			if ( requiresTotalCount ) {
+				return MassIndexingMonitor.super.typeGroupMonitor( context );
+			}
+			else {
+				return new MassIndexingTypeGroupMonitor() {
+					@Override
+					public void documentsIndexed(long increment) {
+						// do nothing
+					}
+
+					@Override
+					public void indexingStarted(MassIndexingTypeGroupMonitorContext context) {
+						// do nothing
+					}
+
+					@Override
+					public void indexingCompleted(MassIndexingTypeGroupMonitorContext context) {
+						// do nothing
+					}
+				};
+			}
+		}
+
 		@Override
 		public void documentsAdded(long increment) {
 			StaticCounters.get().add( ADDED, (int) increment );

mapper/orm/src/main/java/org/hibernate/search/mapper/orm/massindexing/MassIndexer.java

@@ -228,7 +228,8 @@ public interface MassIndexer {
 	 * <p>
 	 * With fail-fast option enabled, the mass indexer will request cancelling all internal mass-indexing processes
 	 * right after the first error is reported to the {@link MassIndexingFailureHandler}.
-	 *
+	 * <p>
+	 * Defaults to {@code false}.
 	 * @param failFast Whether to enabled fail fast option for this mass indexer.
 	 *
 	 * @return {@code this} for method chaining

mapper/pojo-base/src/main/java/org/hibernate/search/mapper/pojo/logging/impl/Log.java

@@ -1041,4 +1041,9 @@ void indexingProgressWithRemainingTime(float estimatePercentileComplete, long do
 	@LogMessage(level = INFO)
 	@Message(id = ID_OFFSET + 168, value = "Mass indexing complete in %3$s. Indexed %1$d/%2$d entities.")
 	void indexingEntitiesCompleted(long indexed, long total, Duration indexingTime);
+
+	@LogMessage(level = INFO)
+	@Message(id = ID_OFFSET + 169,
+			value = "Mass indexing is going to index approx. %1$d entities (%2$s). Actual number may change once the indexing starts.")
+	void indexingEntitiesApprox(long count, String types);
 }