Enable engine factory to be pluggable

server/src/main/java/org/elasticsearch/index/IndexModule.java

@@ -19,8 +19,8 @@
 
 package org.elasticsearch.index;
 
-import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.search.similarities.BM25Similarity;
+import org.apache.lucene.search.similarities.Similarity;
 import org.apache.lucene.util.SetOnce;
 import org.elasticsearch.Version;
 import org.elasticsearch.client.Client;
@@ -60,6 +60,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.function.BiFunction;
@@ -104,8 +105,7 @@ public final class IndexModule {
 
     private final IndexSettings indexSettings;
     private final AnalysisRegistry analysisRegistry;
-    // pkg private so tests can mock
-    final SetOnce<EngineFactory> engineFactory = new SetOnce<>();
+    private final EngineFactory engineFactory;
     private SetOnce<IndexSearcherWrapperFactory> indexSearcherWrapper = new SetOnce<>();
     private final Set<IndexEventListener> indexEventListeners = new HashSet<>();
     private final Map<String, TriFunction<Settings, Version, ScriptService, Similarity>> similarities = new HashMap<>();
@@ -115,9 +115,18 @@ public final class IndexModule {
     private final List<IndexingOperationListener> indexOperationListeners = new ArrayList<>();
     private final AtomicBoolean frozen = new AtomicBoolean(false);
 
-    public IndexModule(IndexSettings indexSettings, AnalysisRegistry analysisRegistry) {
+    /**
+     * Construct the index module for the index with the specified index settings. The index module contains extension points for plugins
+     * via {@link org.elasticsearch.plugins.PluginsService#onIndexModule(IndexModule)}.
+     *
+     * @param indexSettings    the index settings
+     * @param analysisRegistry the analysis registry
+     * @param engineFactory    the engine factory
+     */
+    public IndexModule(final IndexSettings indexSettings, final AnalysisRegistry analysisRegistry, final EngineFactory engineFactory) {
         this.indexSettings = indexSettings;
         this.analysisRegistry = analysisRegistry;
+        this.engineFactory = Objects.requireNonNull(engineFactory);
         this.searchOperationListeners.add(new SearchSlowLog(indexSettings));
         this.indexOperationListeners.add(new IndexingSlowLog(indexSettings));
     }
@@ -158,6 +167,15 @@ public Index getIndex() {
         return indexSettings.getIndex();
     }
 
+    /**
+     * The engine factory provided during construction of this index module.
+     *
+     * @return the engine factory
+     */
+    EngineFactory getEngineFactory() {
+        return engineFactory;
+    }
+
     /**
      * Adds an {@link IndexEventListener} for this index. All listeners added here
      * are maintained for the entire index lifecycle on this node. Once an index is closed or deleted these
@@ -364,7 +382,7 @@ public IndexService newIndexService(
         }
         return new IndexService(indexSettings, environment, xContentRegistry,
                 new SimilarityService(indexSettings, scriptService, similarities),
-                shardStoreDeleter, analysisRegistry, engineFactory.get(), circuitBreakerService, bigArrays, threadPool, scriptService,
+                shardStoreDeleter, analysisRegistry, engineFactory, circuitBreakerService, bigArrays, threadPool, scriptService,
                 client, queryCache, store, eventListener, searcherWrapperFactory, mapperRegistry,
                 indicesFieldDataCache, searchOperationListeners, indexOperationListeners, namedWriteableRegistry);
     }

server/src/main/java/org/elasticsearch/index/IndexService.java

@@ -139,7 +139,7 @@ public IndexService(
             SimilarityService similarityService,
             ShardStoreDeleter shardStoreDeleter,
             AnalysisRegistry registry,
-            @Nullable EngineFactory engineFactory,
+            EngineFactory engineFactory,
             CircuitBreakerService circuitBreakerService,
             BigArrays bigArrays,
             ThreadPool threadPool,
@@ -188,7 +188,7 @@ public IndexService(
         this.warmer = new IndexWarmer(indexSettings.getSettings(), threadPool, indexFieldData,
             bitsetFilterCache.createListener(threadPool));
         this.indexCache = new IndexCache(indexSettings, queryCache, bitsetFilterCache);
-        this.engineFactory = engineFactory;
+        this.engineFactory = Objects.requireNonNull(engineFactory);
         // initialize this last -- otherwise if the wrapper requires any other member to be non-null we fail with an NPE
         this.searcherWrapper = wrapperFactory.newWrapper(this);
         this.searchOperationListeners = Collections.unmodifiableList(searchOperationListeners);
@@ -681,9 +681,9 @@ public interface ShardStoreDeleter {
         void addPendingDelete(ShardId shardId, IndexSettings indexSettings);
     }
 
-    final EngineFactory getEngineFactory() {
+    public final EngineFactory getEngineFactory() {
         return engineFactory;
-    } // pkg private for testing
+    }
 
     final IndexSearcherWrapper getSearcherWrapper() {
         return searcherWrapper;

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -82,7 +82,6 @@
 import org.elasticsearch.index.engine.EngineException;
 import org.elasticsearch.index.engine.EngineFactory;
 import org.elasticsearch.index.engine.InternalEngine;
-import org.elasticsearch.index.engine.InternalEngineFactory;
 import org.elasticsearch.index.engine.RefreshFailedEngineException;
 import org.elasticsearch.index.engine.Segment;
 import org.elasticsearch.index.engine.SegmentsStats;
@@ -194,7 +193,7 @@ public class IndexShard extends AbstractIndexShardComponent implements IndicesCl
     protected volatile IndexShardState state;
     protected volatile long primaryTerm;
     protected final AtomicReference<Engine> currentEngineReference = new AtomicReference<>();
-    protected final EngineFactory engineFactory;
+    final EngineFactory engineFactory;
 
     private final IndexingOperationListener indexingOperationListeners;
     private final Runnable globalCheckpointSyncer;
@@ -267,7 +266,7 @@ public IndexShard(
         this.warmer = warmer;
         this.similarityService = similarityService;
         Objects.requireNonNull(store, "Store must be provided to the index shard");
-        this.engineFactory = engineFactory == null ? new InternalEngineFactory() : engineFactory;
+        this.engineFactory = Objects.requireNonNull(engineFactory);
         this.store = store;
         this.indexSortSupplier = indexSortSupplier;
         this.indexEventListener = indexEventListener;

server/src/main/java/org/elasticsearch/indices/IndicesModule.java

@@ -27,6 +27,8 @@
 import org.elasticsearch.common.geo.ShapesAvailability;
 import org.elasticsearch.common.inject.AbstractModule;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry.Entry;
+import org.elasticsearch.index.IndexSettings;
+import org.elasticsearch.index.engine.EngineFactory;
 import org.elasticsearch.index.mapper.BinaryFieldMapper;
 import org.elasticsearch.index.mapper.BooleanFieldMapper;
 import org.elasticsearch.index.mapper.CompletionFieldMapper;
@@ -60,10 +62,12 @@
 import org.elasticsearch.plugins.MapperPlugin;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -234,4 +238,9 @@ protected void configure() {
     public MapperRegistry getMapperRegistry() {
         return mapperRegistry;
     }
+
+    public Collection<Function<IndexSettings, Optional<EngineFactory>>> getEngineFactories() {
+        return Collections.emptyList();
+    }
+
 }

server/src/main/java/org/elasticsearch/indices/IndicesService.java

@@ -25,7 +25,6 @@
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.LockObtainFailedException;
 import org.apache.lucene.util.CollectionUtil;
-import org.elasticsearch.core.internal.io.IOUtils;
 import org.apache.lucene.util.RamUsageEstimator;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ResourceAlreadyExistsException;
@@ -45,6 +44,7 @@
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.breaker.CircuitBreaker;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.component.AbstractLifecycleComponent;
 import org.elasticsearch.common.io.FileSystemUtils;
 import org.elasticsearch.common.io.stream.BytesStreamOutput;
@@ -67,6 +67,7 @@
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.core.internal.io.IOUtils;
 import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.env.ShardLock;
 import org.elasticsearch.env.ShardLockObtainFailedException;
@@ -79,6 +80,8 @@
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.AnalysisRegistry;
 import org.elasticsearch.index.cache.request.ShardRequestCache;
+import org.elasticsearch.index.engine.EngineFactory;
+import org.elasticsearch.index.engine.InternalEngineFactory;
 import org.elasticsearch.index.fielddata.IndexFieldDataCache;
 import org.elasticsearch.index.flush.FlushStats;
 import org.elasticsearch.index.get.GetStats;
@@ -116,10 +119,14 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
@@ -172,6 +179,7 @@ public class IndicesService extends AbstractLifecycleComponent
     private final IndicesRequestCache indicesRequestCache;
     private final IndicesQueryCache indicesQueryCache;
     private final MetaStateService metaStateService;
+    private final Collection<Function<IndexSettings, Optional<EngineFactory>>> engineFactoryProviders;
 
     @Override
     protected void doStart() {
@@ -183,7 +191,8 @@ public IndicesService(Settings settings, PluginsService pluginsService, NodeEnvi
                           AnalysisRegistry analysisRegistry, IndexNameExpressionResolver indexNameExpressionResolver,
                           MapperRegistry mapperRegistry, NamedWriteableRegistry namedWriteableRegistry, ThreadPool threadPool,
                           IndexScopedSettings indexScopedSettings, CircuitBreakerService circuitBreakerService, BigArrays bigArrays,
-                          ScriptService scriptService, Client client, MetaStateService metaStateService) {
+                          ScriptService scriptService, Client client, MetaStateService metaStateService,
+                          Collection<Function<IndexSettings, Optional<EngineFactory>>> engineFactoryProviders) {
         super(settings);
         this.threadPool = threadPool;
         this.pluginsService = pluginsService;
@@ -214,6 +223,7 @@ public void onRemoval(ShardId shardId, String fieldName, boolean wasEvicted, lon
         this.cleanInterval = INDICES_CACHE_CLEAN_INTERVAL_SETTING.get(settings);
         this.cacheCleaner = new CacheCleaner(indicesFieldDataCache, indicesRequestCache,  logger, threadPool, this.cleanInterval);
         this.metaStateService = metaStateService;
+        this.engineFactoryProviders = engineFactoryProviders;
     }
 
     @Override
@@ -442,7 +452,7 @@ private synchronized IndexService createIndexService(final String reason,
             idxSettings.getNumberOfReplicas(),
             reason);
 
-        final IndexModule indexModule = new IndexModule(idxSettings, analysisRegistry);
+        final IndexModule indexModule = new IndexModule(idxSettings, analysisRegistry, getEngineFactory(idxSettings));
         for (IndexingOperationListener operationListener : indexingOperationListeners) {
             indexModule.addIndexOperationListener(operationListener);
         }
@@ -466,6 +476,34 @@ private synchronized IndexService createIndexService(final String reason,
         );
     }
 
+    private EngineFactory getEngineFactory(final IndexSettings idxSettings) {
+        final List<Optional<EngineFactory>> engineFactories =
+                engineFactoryProviders
+                        .stream()
+                        .map(engineFactoryProvider -> engineFactoryProvider.apply(idxSettings))
+                        .filter(maybe -> Objects.requireNonNull(maybe).isPresent())
+                        .collect(Collectors.toList());
+        if (engineFactories.isEmpty()) {
+            return new InternalEngineFactory();
+        } else if (engineFactories.size() == 1) {
+            assert engineFactories.get(0).isPresent();
+            return engineFactories.get(0).get();
+        } else {
+            final String message = String.format(
+                    Locale.ROOT,
+                    "multiple engine factories provided for %s: %s",
+                    idxSettings.getIndex(),
+                    engineFactories
+                            .stream()
+                            .map(t -> {
+                                assert t.isPresent();
+                                return "[" + t.get().getClass().getName() + "]";
+                            })
+                            .collect(Collectors.joining(",")));
+            throw new IllegalStateException(message);
+        }
+    }
+
     /**
      * creates a new mapper service for the given index, in order to do administrative work like mapping updates.
      * This *should not* be used for document parsing. Doing so will result in an exception.
@@ -474,7 +512,7 @@ private synchronized IndexService createIndexService(final String reason,
      */
     public synchronized MapperService createIndexMapperService(IndexMetaData indexMetaData) throws IOException {
         final IndexSettings idxSettings = new IndexSettings(indexMetaData, this.settings, indexScopedSettings);
-        final IndexModule indexModule = new IndexModule(idxSettings, analysisRegistry);
+        final IndexModule indexModule = new IndexModule(idxSettings, analysisRegistry, getEngineFactory(idxSettings));
         pluginsService.onIndexModule(indexModule);
         return indexModule.newIndexMapperService(xContentRegistry, mapperRegistry, scriptService);
     }

server/src/main/java/org/elasticsearch/node/Node.java

@@ -21,7 +21,6 @@
 
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.util.Constants;
-import org.elasticsearch.core.internal.io.IOUtils;
 import org.apache.lucene.util.SetOnce;
 import org.elasticsearch.Build;
 import org.elasticsearch.ElasticsearchException;
@@ -58,12 +57,10 @@
 import org.elasticsearch.common.StopWatch;
 import org.elasticsearch.common.component.Lifecycle;
 import org.elasticsearch.common.component.LifecycleComponent;
-import org.elasticsearch.common.inject.Binder;
 import org.elasticsearch.common.inject.Injector;
 import org.elasticsearch.common.inject.Key;
 import org.elasticsearch.common.inject.Module;
 import org.elasticsearch.common.inject.ModulesBuilder;
-import org.elasticsearch.common.inject.util.Providers;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.lease.Releasables;
 import org.elasticsearch.common.logging.DeprecationLogger;
@@ -82,6 +79,7 @@
 import org.elasticsearch.common.util.BigArrays;
 import org.elasticsearch.common.util.PageCacheRecycler;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
+import org.elasticsearch.core.internal.io.IOUtils;
 import org.elasticsearch.discovery.Discovery;
 import org.elasticsearch.discovery.DiscoveryModule;
 import org.elasticsearch.discovery.DiscoverySettings;
@@ -93,8 +91,10 @@
 import org.elasticsearch.gateway.GatewayService;
 import org.elasticsearch.gateway.MetaStateService;
 import org.elasticsearch.http.HttpServerTransport;
-import org.elasticsearch.http.HttpTransportSettings;
+import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.AnalysisRegistry;
+import org.elasticsearch.index.engine.Engine;
+import org.elasticsearch.index.engine.EngineFactory;
 import org.elasticsearch.indices.IndicesModule;
 import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.indices.analysis.AnalysisModule;
@@ -109,10 +109,15 @@
 import org.elasticsearch.ingest.IngestService;
 import org.elasticsearch.monitor.MonitorService;
 import org.elasticsearch.monitor.jvm.JvmInfo;
+import org.elasticsearch.persistent.PersistentTasksClusterService;
+import org.elasticsearch.persistent.PersistentTasksExecutor;
+import org.elasticsearch.persistent.PersistentTasksExecutorRegistry;
+import org.elasticsearch.persistent.PersistentTasksService;
 import org.elasticsearch.plugins.ActionPlugin;
 import org.elasticsearch.plugins.AnalysisPlugin;
 import org.elasticsearch.plugins.ClusterPlugin;
 import org.elasticsearch.plugins.DiscoveryPlugin;
+import org.elasticsearch.plugins.EnginePlugin;
 import org.elasticsearch.plugins.IngestPlugin;
 import org.elasticsearch.plugins.MapperPlugin;
 import org.elasticsearch.plugins.MetaDataUpgrader;
@@ -140,10 +145,6 @@
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.usage.UsageService;
 import org.elasticsearch.watcher.ResourceWatcherService;
-import org.elasticsearch.persistent.PersistentTasksClusterService;
-import org.elasticsearch.persistent.PersistentTasksExecutor;
-import org.elasticsearch.persistent.PersistentTasksExecutorRegistry;
-import org.elasticsearch.persistent.PersistentTasksService;
 
 import java.io.BufferedWriter;
 import java.io.Closeable;
@@ -161,6 +162,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -395,11 +397,21 @@ protected Node(final Environment environment, Collection<Class<? extends Plugin>
                 .flatMap(Function.identity()).collect(toList()));
             modules.add(new RepositoriesModule(this.environment, pluginsService.filterPlugins(RepositoryPlugin.class), xContentRegistry));
             final MetaStateService metaStateService = new MetaStateService(settings, nodeEnvironment, xContentRegistry);
-            final IndicesService indicesService = new IndicesService(settings, pluginsService, nodeEnvironment, xContentRegistry,
-                    analysisModule.getAnalysisRegistry(),
-                clusterModule.getIndexNameExpressionResolver(), indicesModule.getMapperRegistry(), namedWriteableRegistry,
-                threadPool, settingsModule.getIndexScopedSettings(), circuitBreakerService, bigArrays, scriptModule.getScriptService(),
-                client, metaStateService);
+
+            // collect engine factory providers from server and from plugins
+            final Collection<EnginePlugin> enginePlugins = pluginsService.filterPlugins(EnginePlugin.class);
+            final Collection<Function<IndexSettings, Optional<EngineFactory>>> engineFactoryProviders =
+                    Stream.concat(
+                            indicesModule.getEngineFactories().stream(),
+                            enginePlugins.stream().map(plugin -> plugin::getEngineFactory))
+                    .collect(Collectors.toList());
+
+            final IndicesService indicesService =
+                    new IndicesService(settings, pluginsService, nodeEnvironment, xContentRegistry, analysisModule.getAnalysisRegistry(),
+                            clusterModule.getIndexNameExpressionResolver(), indicesModule.getMapperRegistry(), namedWriteableRegistry,
+                            threadPool, settingsModule.getIndexScopedSettings(), circuitBreakerService, bigArrays,
+                            scriptModule.getScriptService(), client, metaStateService, engineFactoryProviders);
+
 
             Collection<Object> pluginComponents = pluginsService.filterPlugins(Plugin.class).stream()
                 .flatMap(p -> p.createComponents(client, clusterService, threadPool, resourceWatcherService,