arp7 commented on a change in pull request #1130: HDDS-1827. Load Snapshot info when OM Ratis server starts. URL: https://github.com/apache/hadoop/pull/1130#discussion_r314826158
########## File path: hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/ratis/OMRatisSnapshotInfo.java ########## @@ -0,0 +1,133 @@ +/** + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.ozone.om.ratis; + +import org.apache.ratis.server.protocol.TermIndex; +import org.apache.ratis.server.storage.FileInfo; +import org.apache.ratis.statemachine.SnapshotInfo; +import org.apache.hadoop.ozone.om.OzoneManager; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.BufferedReader; +import java.io.BufferedWriter; +import java.io.File; +import java.io.FileReader; +import java.io.FileWriter; +import java.io.IOException; +import java.util.List; + +import static org.apache.hadoop.ozone.OzoneConsts.OM_RATIS_SNAPSHOT_INDEX; + +/** + * This class captures the {@link OzoneManager#snapshotIndex} and term of the + * snapshot. + * Ratis server loads the snapshotInfo during startup and updates the + * lastApplied index to this snapshotIndex. OM SnaphsotInfo does not contain + * any files. It is used only to store/ update the last applied index and term. + */ +public class OMRatisSnapshotInfo implements SnapshotInfo { + + static final Logger LOG = LoggerFactory.getLogger(OMRatisSnapshotInfo.class); + + private volatile long term = 0; + private volatile long snapshotIndex = -1; + + private final File ratisSnapshotFile; + + private final static String TERM_PREFIX = "term"; + private final static String INDEX_PREFIX = "index"; + private final static String SEPARATOR = ":"; + + public OMRatisSnapshotInfo(File ratisDir) throws IOException { + ratisSnapshotFile = new File(ratisDir, OM_RATIS_SNAPSHOT_INDEX); + loadRatisSnapshotIndex(); + } + + public void updateTerm(long newTerm) { + term = newTerm; + } + + public void updateSnapshotIndex(long newSnapshotIndex) { + snapshotIndex = newSnapshotIndex; + } + + public void updateTermIndex(long newTerm, long newIndex) { + this.term = newTerm; + this.snapshotIndex = newIndex; + } + + /** + * Load the snapshot index and term from the snapshot file on disk, + * if it exists. + * @throws IOException + */ + public void loadRatisSnapshotIndex() throws IOException { + if (ratisSnapshotFile.exists()) { + try (BufferedReader reader = new BufferedReader(new FileReader( + ratisSnapshotFile))) { + String termStr = reader.readLine(); + String indexStr = reader.readLine(); + + updateTermIndex(Long.parseLong(termStr.split(SEPARATOR)[1]), + Long.parseLong(indexStr.split(SEPARATOR)[1])); + + } catch (IOException e) { + LOG.error("Failed to load Ratis Snapshot file {}", ratisSnapshotFile); Review comment: Don't log and rethrow. Instead wrap the exception in another exception that has the log message here and then rethrow the outer exception. https://community.oracle.com/docs/DOC-983543#logAndThrow The Oracle website has some strong text - I don't think it is quite that bad of a pattern but still good to avoid. 🙂 ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
