Directory類(lèi)繼承樹(shù)

在IndicesService的createIndexService函數(shù)中馒铃，IndicesService創(chuàng)建IndexModule實(shí)例對(duì)象痕惋，IndexModule創(chuàng)建IndexStore實(shí)例對(duì)象娃殖，IndexStore創(chuàng)建FsDirectoryService實(shí)例對(duì)象

IndicesService::createIndexService

private synchronized IndexService createIndexService(final String reason, IndexMetaData indexMetaData, IndicesQueryCache indicesQueryCache, IndicesFieldDataCache indicesFieldDataCache, List<IndexEventListener> builtInListeners, IndexingOperationListener... indexingOperationListeners) throws IOException {
    final Index index = indexMetaData.getIndex();
    final Predicate<String> indexNameMatcher = (indexExpression) -> indexNameExpressionResolver.matchesIndex(index.getName(), indexExpression, clusterService.state());
    final IndexSettings idxSettings = new IndexSettings(indexMetaData, this.settings, indexNameMatcher, indexScopeSetting);
    ...
 
    final IndexModule indexModule = new IndexModule(idxSettings, indexStoreConfig, analysisRegistry);  // 創(chuàng)建IndexModule
    ...
 
    return indexModule.newIndexService(nodeEnv, xContentRegistry, this, circuitBreakerService, bigArrays, threadPool, scriptService,
            clusterService, client, indicesQueryCache, mapperRegistry, indicesFieldDataCache);  // 托管IndexModule創(chuàng)建IndexService
}

IndexModule::newIndexService

public IndexService newIndexService(NodeEnvironment environment, NamedXContentRegistry xContentRegistry,
        IndexService.ShardStoreDeleter shardStoreDeleter, CircuitBreakerService circuitBreakerService, BigArrays bigArrays,
        ThreadPool threadPool, ScriptService scriptService,
        ClusterService clusterService, Client client, IndicesQueryCache indicesQueryCache, MapperRegistry mapperRegistry,
        IndicesFieldDataCache indicesFieldDataCache) throws IOException {
 
    ...;
    final String storeType = indexSettings.getValue(INDEX_STORE_TYPE_SETTING);
    final IndexStore store;
    if (Strings.isEmpty(storeType) || isBuiltinType(storeType)) {  // IndexModule提供了5種類(lèi)型的文件系統(tǒng)：NIOFS述寡，MMAPFS叶洞，SIMPLEFS，F(xiàn)S螟炫，DEFAULT
        store = new IndexStore(indexSettings, indexStoreConfig);
    } else {  // 也可實(shí)現(xiàn)自定義的IndexStore艺晴，通過(guò)調(diào)用addIndexStore(String type, BiFunction<IndexSettings, IndexStoreConfig, IndexStore> provider)函數(shù)去注冊(cè)自定義IndexStore
        BiFunction<IndexSettings, IndexStoreConfig, IndexStore> factory = storeTypes.get(storeType);
        if (factory == null) {
            throw new IllegalArgumentException("Unknown store type [" + storeType + "]");
        }
        store = factory.apply(indexSettings, indexStoreConfig);
        if (store == null) {
            throw new IllegalStateException("store must not be null");
        }
    }
    indexSettings.getScopedSettings().addSettingsUpdateConsumer(IndexStore.INDEX_STORE_THROTTLE_TYPE_SETTING, store::setType);  // index.store.throttle.type, 節(jié)流控制
    indexSettings.getScopedSettings().addSettingsUpdateConsumer(IndexStore.INDEX_STORE_THROTTLE_MAX_BYTES_PER_SEC_SETTING,
        store::setMaxRate);  // index.store.throttle.max_bytes_per_sec, 節(jié)流控制
    ...;
    return new IndexService(indexSettings, environment, xContentRegistry, new SimilarityService(indexSettings, similarities),
            shardStoreDeleter, analysisRegistry, engineFactory.get(), circuitBreakerService, bigArrays, threadPool, scriptService,
            clusterService, client, queryCache, store, eventListener, searcherWrapperFactory, mapperRegistry,
            indicesFieldDataCache, searchOperationListeners, indexOperationListeners);
}

IndexStore::newDirectoryService

public DirectoryService newDirectoryService(ShardPath path) {
    return new FsDirectoryService(indexSettings, this, path);
}

FsDirectoryService

FsDirectoryService創(chuàng)建目錄時(shí)主要做兩件事：獲取文件鎖封寞，以及根據(jù)指定類(lèi)型創(chuàng)建對(duì)應(yīng)類(lèi)型的目錄對(duì)象

FsDirectoryService::newDirectory

    @Override
    public Directory newDirectory() throws IOException {
        final Path location = path.resolveIndex();  // 獲取目錄位置
        final LockFactory lockFactory = indexSettings.getValue(INDEX_LOCK_FACTOR_SETTING);  // 獲取文件鎖
        Files.createDirectories(location);
        Directory wrapped = newFSDirectory(location, lockFactory);  // 根據(jù)指定類(lèi)型創(chuàng)建對(duì)應(yīng)類(lèi)型的目錄對(duì)象
        Set<String> preLoadExtensions = new HashSet<>(
                indexSettings.getValue(IndexModule.INDEX_STORE_PRE_LOAD_SETTING));
        wrapped = setPreload(wrapped, location, lockFactory, preLoadExtensions);  // MMapFS文件系統(tǒng)在將文件映射到應(yīng)用程序內(nèi)存時(shí)進(jìn)行預(yù)加載操作狈究，將數(shù)據(jù)寫(xiě)進(jìn)MappedByteBuffer
        if (indexSettings.isOnSharedFilesystem()) {
            wrapped = new SleepingLockWrapper(wrapped, 5000);
        }
        return new RateLimitedFSDirectory(wrapped, this, this) ;
    }
  
    protected Directory newFSDirectory(Path location, LockFactory lockFactory) throws IOException {
        final String storeType = indexSettings.getSettings().get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(),
            IndexModule.Type.FS.getSettingsKey());
        if (IndexModule.Type.FS.match(storeType)) {
            return FSDirectory.open(location, lockFactory); // use lucene defaults
        } else if (IndexModule.Type.DEFAULT.match(storeType)) {
            deprecationLogger.deprecated("[default] store type is deprecated, use [fs] instead");
            return FSDirectory.open(location, lockFactory); // use lucene defaults
        } else if (IndexModule.Type.SIMPLEFS.match(storeType)) {
            return new SimpleFSDirectory(location, lockFactory);
        } else if (IndexModule.Type.NIOFS.match(storeType)) {
            return new NIOFSDirectory(location, lockFactory);
        } else if (IndexModule.Type.MMAPFS.match(storeType)) {
            return new MMapDirectory(location, lockFactory);
        }
        throw new IllegalArgumentException("No directory found for type [" + storeType + "]");
    }

FSDirectoryService文件鎖

由index.store.fs.fs_lock參數(shù)指定抖锥，可選[native, simple]磅废，默認(rèn)native

FSDirectory文件類(lèi)型