Java tutorial
/* * 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.nifi.toolkit.zkmigrator; import com.google.common.base.Preconditions; import com.google.common.base.Strings; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.DefaultParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Option; import org.apache.commons.cli.OptionGroup; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.nifi.toolkit.zkmigrator.ZooKeeperMigrator.AuthMode; import org.apache.zookeeper.KeeperException; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintStream; import java.nio.charset.StandardCharsets; import java.nio.file.Paths; import java.util.concurrent.ExecutionException; public class ZooKeeperMigratorMain { enum Mode { READ, WRITE } private static final String JAVA_HOME = "JAVA_HOME"; private static final String NIFI_TOOLKIT_HOME = "NIFI_TOOLKIT_HOME"; private static final String HEADER = System.lineSeparator() + "A tool for importing and exporting data from ZooKeeper." + System.lineSeparator() + System.lineSeparator(); private static final String FOOTER = System.lineSeparator() + "Java home: " + System.getenv(JAVA_HOME) + System.lineSeparator() + "NiFi Toolkit home: " + System.getenv(NIFI_TOOLKIT_HOME); private static final Option OPTION_ZK_MIGRATOR_HELP = Option.builder("h").longOpt("help") .desc("display help/usage info").build(); private static final Option OPTION_ZK_ENDPOINT = Option.builder("z").longOpt("zookeeper") .desc("ZooKeeper endpoint string (ex. host:port/path)").hasArg().argName("zookeeper-endpoint") .required().build(); private static final Option OPTION_RECEIVE = Option.builder("r").longOpt("receive") .desc("receives data from zookeeper and writes to the given filename or standard output").build(); private static final Option OPTION_SEND = Option.builder("s").longOpt("send") .desc("sends data to zookeeper read from the given filename or standard input").build(); private static final Option OPTION_ZK_AUTH_INFO = Option.builder("a").longOpt("auth") .desc("username and password for the given ZooKeeper path").hasArg().argName("username:password") .build(); private static final Option OPTION_ZK_KRB_CONF_FILE = Option.builder("k").longOpt("krb-conf") .desc("JAAS file containing Kerberos config").hasArg().argName("jaas-filename").numberOfArgs(1).build(); private static final Option OPTION_FILE = Option.builder("f").longOpt("file") .desc("file to be used for ZooKeeper data").hasArg().argName("filename").build(); private static final Option OPTION_IGNORE_SOURCE = Option.builder().longOpt("ignore-source") .desc("ignores the source ZooKeeper endpoint specified in the exported data").build(); private static Options createOptions() { final Options options = new Options(); options.addOption(OPTION_ZK_MIGRATOR_HELP); options.addOption(OPTION_ZK_ENDPOINT); options.addOption(OPTION_ZK_AUTH_INFO); options.addOption(OPTION_FILE); options.addOption(OPTION_IGNORE_SOURCE); final OptionGroup optionGroupAuth = new OptionGroup().addOption(OPTION_ZK_AUTH_INFO) .addOption(OPTION_ZK_KRB_CONF_FILE); optionGroupAuth.setRequired(false); options.addOptionGroup(optionGroupAuth); final OptionGroup optionGroupReadWrite = new OptionGroup().addOption(OPTION_RECEIVE).addOption(OPTION_SEND); optionGroupReadWrite.setRequired(true); options.addOptionGroup(optionGroupReadWrite); return options; } private static void printUsage(String errorMessage, Options options) { Preconditions.checkNotNull(options, "command line options were not specified"); if (errorMessage != null) { System.out.println(errorMessage + System.lineSeparator()); } HelpFormatter helpFormatter = new HelpFormatter(); helpFormatter.setWidth(160); helpFormatter.setDescPadding(0); helpFormatter.printHelp(ZooKeeperMigratorMain.class.getCanonicalName(), HEADER, options, FOOTER, true); } public static void main(String[] args) throws IOException { PrintStream output = System.out; System.setOut(System.err); final Options options = createOptions(); final CommandLine commandLine; try { commandLine = new DefaultParser().parse(options, args); if (commandLine.hasOption(OPTION_ZK_MIGRATOR_HELP.getLongOpt())) { printUsage(null, options); } else { final String zookeeperUri = commandLine.getOptionValue(OPTION_ZK_ENDPOINT.getOpt()); final Mode mode = commandLine.hasOption(OPTION_RECEIVE.getOpt()) ? Mode.READ : Mode.WRITE; final String filename = commandLine.getOptionValue(OPTION_FILE.getOpt()); final String auth = commandLine.getOptionValue(OPTION_ZK_AUTH_INFO.getOpt()); final String jaasFilename = commandLine.getOptionValue(OPTION_ZK_KRB_CONF_FILE.getOpt()); final boolean ignoreSource = commandLine.hasOption(OPTION_IGNORE_SOURCE.getLongOpt()); final AuthMode authMode; final byte[] authData; if (auth != null) { authMode = AuthMode.DIGEST; authData = auth.getBytes(StandardCharsets.UTF_8); } else { authData = null; if (!Strings.isNullOrEmpty(jaasFilename)) { authMode = AuthMode.SASL; System.setProperty("java.security.auth.login.config", jaasFilename); } else { authMode = AuthMode.OPEN; } } final ZooKeeperMigrator zookeeperMigrator = new ZooKeeperMigrator(zookeeperUri); if (mode.equals(Mode.READ)) { try (OutputStream zkData = filename != null ? new FileOutputStream(Paths.get(filename).toFile()) : output) { zookeeperMigrator.readZooKeeper(zkData, authMode, authData); } } else { try (InputStream zkData = filename != null ? new FileInputStream(Paths.get(filename).toFile()) : System.in) { zookeeperMigrator.writeZooKeeper(zkData, authMode, authData, ignoreSource); } } } } catch (ParseException e) { printUsage(e.getLocalizedMessage(), options); } catch (IOException | KeeperException | InterruptedException | ExecutionException e) { throw new IOException(String.format("unable to perform operation: %s", e.getLocalizedMessage()), e); } } }