/** * * 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.hadoop.hbase.wal; import java.io.Closeable; import java.io.IOException; import java.util.List; import java.util.OptionalLong; import java.util.concurrent.CompletableFuture; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.client.RegionInfo; import org.apache.hadoop.hbase.regionserver.wal.WALActionsListener; import org.apache.hadoop.hbase.replication.regionserver.WALFileLengthProvider; import org.apache.yetus.audience.InterfaceAudience; /** * The Write Ahead Log (WAL) stores all durable edits to the HRegion. This interface provides the * entry point for all WAL implementors. * <p> * See {@link FSHLogProvider} for an example implementation. A single WALProvider will be used for * retrieving multiple WALs in a particular region server and must be threadsafe. */ @InterfaceAudience.Private public interface WALProvider { /** * Set up the provider to create wals. will only be called once per instance. * @param factory factory that made us may not be null * @param conf may not be null * @param providerId differentiate between providers from one factory. may be null */ void init(WALFactory factory, Configuration conf, String providerId) throws IOException; /** * @param region the region which we want to get a WAL for it. Could be null. * @return a WAL for writing entries for the given region. */ WAL getWAL(RegionInfo region) throws IOException; /** * @return the List of WALs that are used by this server */ List<WAL> getWALs(); /** * persist outstanding WALs to storage and stop accepting new appends. This method serves as * shorthand for sending a sync to every WAL provided by a given implementation. Those WALs will * also stop accepting new writes. */ void shutdown() throws IOException; /** * shutdown utstanding WALs and clean up any persisted state. Call this method only when you will * not need to replay any of the edits to the WALs from this provider. After this call completes, * the underlying resources should have been reclaimed. */ void close() throws IOException; interface WriterBase extends Closeable { long getLength(); } // Writers are used internally. Users outside of the WAL should be relying on the // interface provided by WAL. interface Writer extends WriterBase { void sync(boolean forceSync) throws IOException; void append(WAL.Entry entry) throws IOException; } interface AsyncWriter extends WriterBase { CompletableFuture<Long> sync(boolean forceSync); void append(WAL.Entry entry); } /** * Get number of the log files this provider is managing */ long getNumLogFiles(); /** * Get size of the log files this provider is managing */ long getLogFileSize(); /** * Add a {@link WALActionsListener}. * <p> * Notice that you must call this method before calling {@link #getWAL(RegionInfo)} as this method * will not effect the {@link WAL} which has already been created. And as long as we can only it * when initialization, it is not thread safe. */ void addWALActionsListener(WALActionsListener listener); default WALFileLengthProvider getWALFileLengthProvider() { return path -> getWALs().stream().map(w -> w.getLogFileSizeIfBeingWritten(path)) .filter(o -> o.isPresent()).findAny().orElse(OptionalLong.empty()); } }