sijie commented on a change in pull request #266: Issue 265: Add persistable bookie status URL: https://github.com/apache/bookkeeper/pull/266#discussion_r129105288
########## File path: bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/BookieStatus.java ########## @@ -0,0 +1,246 @@ +/** + * 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.bookkeeper.bookie; + +import static com.google.common.base.Charsets.UTF_8; +import static org.apache.bookkeeper.util.BookKeeperConstants.BOOKIE_STATUS_FILENAME; + +import java.io.BufferedReader; +import java.io.BufferedWriter; +import java.io.File; +import java.io.FileInputStream; +import java.io.FileOutputStream; +import java.io.IOException; +import java.io.InputStreamReader; +import java.io.OutputStreamWriter; +import java.util.List; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * The status object represents the current status of a bookie instance. + */ +public class BookieStatus { + static Logger LOG = LoggerFactory.getLogger(BookieStatus.class); + static final int CURRENT_STATUS_LAYOUT_VERSION = 1; + + enum BookieMode { + READ_ONLY, + READ_WRITE; + } + + private final static long INVALID_UPDATE_TIME = -1; + + private int layoutVersion; + private long lastUpdateTime; + private BookieMode bookieMode; + + + BookieStatus() { + this.bookieMode = BookieMode.READ_WRITE; + this.layoutVersion = CURRENT_STATUS_LAYOUT_VERSION; + this.lastUpdateTime = INVALID_UPDATE_TIME; + } + + private synchronized BookieMode getBookieMode() { + return bookieMode; + } + + public synchronized boolean isInWritable() { + return bookieMode.equals(BookieMode.READ_WRITE); + } + + synchronized boolean setToWritableMode() { + if (!bookieMode.equals(BookieMode.READ_WRITE)) { + bookieMode = BookieMode.READ_WRITE; + this.lastUpdateTime = System.currentTimeMillis(); + return true; + } + return false; + } + + synchronized boolean isInReadOnlyMode() { + return bookieMode.equals(BookieMode.READ_ONLY); + } + + synchronized boolean setToReadOnlyMode() { + if (!bookieMode.equals(BookieMode.READ_ONLY)) { + bookieMode = BookieMode.READ_ONLY; + this.lastUpdateTime = System.currentTimeMillis(); + return true; + } + return false; + } + + /** + * Write bookie status to multiple directories in best effort + * + * @param directories list of directories to write to + * @return true if any write succeed, false if all failed + * + */ + synchronized boolean writeToDirectories(List<File> directories) { + boolean success = false; + for (File dir : directories) { + try { + File statusFile = new File(dir, BOOKIE_STATUS_FILENAME); + writeToFile(statusFile, toString()); + success = true; + } catch (IOException e) { + LOG.warn("IOException while trying to write bookie status to directory {}." + + " This is fine if not all directories are failed.", dir); + } + } + if(success){ + LOG.info("Successfully persist bookie status {}", this.bookieMode); + } else { + LOG.warn("Failed to persist bookie status {}", this.bookieMode); + } + return success; + } + + /** + * Write content to the file. If file does not exist, it will create one. + * + * @param file file that you want to write to + * @param body content to write + * @throws IOException + */ + private void writeToFile(File file, String body) throws IOException { + FileOutputStream fos = new FileOutputStream(file); + BufferedWriter bw = null; + try { + bw = new BufferedWriter(new OutputStreamWriter(fos, UTF_8)); + bw.write(body); + } finally { + if (bw != null) { + bw.close(); + } + fos.close(); + } + } + + /** + * Read bookie status from the status files, and update the bookie status if read succeed. + * If a status file is not readable or not found, it will skip and try to read from the next file. + * + * @param directories list of directories that store the status file + * @return true if successfully read from file, otherwise false. + */ + boolean readFromDirectories(List<File> directories) { + boolean success = false; + for (File dir : directories) { + File statusFile = new File(dir, BOOKIE_STATUS_FILENAME); + try { + BookieStatus status = readFromFile(statusFile); + if (null != status) { + synchronized (status) { + if (status.lastUpdateTime > this.lastUpdateTime) { + this.lastUpdateTime = status.lastUpdateTime; + this.layoutVersion = status.layoutVersion; + this.bookieMode = status.bookieMode; + success = true; + } + } + } + } catch (IOException e) { + LOG.warn("IOException while trying to read bookie status from directory {}." + + " This is fine if not all directories failed.", dir); + } catch (IllegalArgumentException e ){ + LOG.warn("IllegalArgumentException while trying to read bookie status from directory {}." + + " This is fine if not all directories failed.", dir); + } + } + if (success) { Review comment: the status with latest 'lastUpdateTime' wins. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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