ZOOKEEPER-5037: Add export and import commands to the CLI

zookeeper-docs/src/main/resources/markdown/zookeeperCLI.md

@@ -46,11 +46,13 @@ ZooKeeper -server host:port cmd args
 	deleteall path
 	delquota [-n|-b|-N|-B] path
 	exit
+	export path filepath
 	get [-s] [-w] path
 	getAcl [-s] path
 	getAllChildrenNumber path
 	getEphemerals path
 	history
+	import path filepath
 	listquota path
 	ls [-s] [-w] [-R] path
 	printwatches on|off
@@ -194,8 +196,15 @@ Delete the quota under a path
 [zkshell: 4] delquota -N /c2
 [zkshell: 5] delquota -b /c3
 [zkshell: 6] delquota -B /c4
+```
+
+## export
+Download the contents of a znode to an external file
 
+```bash
+[zkshell: 1] export /zookeeper/config path/to/config.txt
 ```
+
 ## get
 Get the data of the specific path
 
@@ -285,6 +294,13 @@ Showing the history about the recent 11 commands that you have executed
 	7 - history
 ```
 
+## import
+Upload the contents of an external file to a znode, replacing the znode's previous contents
+
+```bash
+[zkshell: 1] import /zookeeper/config path/to/config.txt
+```
+
 ## listquota
 Listing the quota of one path
 

zookeeper-server/src/main/java/org/apache/zookeeper/cli/CommandFactory.java

@@ -38,6 +38,8 @@ public enum Command {
         LS(LsCommand::new),
         GET_ACL(GetAclCommand::new),
         SET_ACL(SetAclCommand::new),
+        EXPORT(ExportCommand::new),
+        IMPORT(ImportCommand::new),
         STAT(StatCommand::new),
         SYNC(SyncCommand::new),
         SET_QUOTA(SetQuotaCommand::new),

zookeeper-server/src/main/java/org/apache/zookeeper/cli/ExportCommand.java

@@ -0,0 +1,93 @@
+/**
+ * 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.zookeeper.cli;
+
+import org.apache.commons.cli.CommandLine;
+import org.apache.commons.cli.CommandLineParser;
+import org.apache.commons.cli.DefaultParser;
+import org.apache.commons.cli.Options;
+import org.apache.commons.cli.ParseException;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.data.Stat;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+
+/**
+ * export command for cli
+ */
+public class ExportCommand extends CliCommand {
+
+    private static Options options = new Options();
+    private String args[];
+    private CommandLine cl;
+
+    static {
+        options.addOption("s", false, "stats");
+        options.addOption("w", false, "watch");
+    }
+
+    public ExportCommand() {
+        super("export", "[-s] [-w] path filepath");
+    }
+
+    @Override
+    public CliCommand parse(String[] cmdArgs) throws CliParseException {
+
+        CommandLineParser parser = new DefaultParser();
+        try {
+            cl = parser.parse(options, cmdArgs);
+        } catch (ParseException ex) {
+            throw new CliParseException(ex);
+        }
+        args = cl.getArgs();
+        if (args.length < 3) {
+            throw new CliParseException(getUsageStr());
+        }
+
+        return this;
+    }
+
+    @Override
+    public boolean exec() throws CliException {
+        boolean watch = cl.hasOption("w");
+        String path = args[1];
+        String filepath = args[2];
+        Stat stat = new Stat();
+        byte data[];
+        try {
+            data = zk.getData(path, watch, stat);
+        } catch (IllegalArgumentException ex) {
+            throw new MalformedPathException(ex.getMessage());
+        } catch (KeeperException|InterruptedException ex) {
+            throw new CliException(ex);
+        }
+        data = (data == null) ? "null".getBytes() : data;
+        try {
+            Files.write(Paths.get(filepath), data, StandardOpenOption.CREATE);
+        } catch (IOException ex) {
+            throw new CliException("Unable to write data to file \"" + filepath + "\"", ex);
+        }
+        if (cl.hasOption("s")) {
+            new StatPrinter(out).print(stat);
+        }
+        return watch;
+    }
+}

zookeeper-server/src/main/java/org/apache/zookeeper/cli/ImportCommand.java

@@ -0,0 +1,95 @@
+/**
+ * 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.zookeeper.cli;
+
+import org.apache.commons.cli.CommandLine;
+import org.apache.commons.cli.CommandLineParser;
+import org.apache.commons.cli.DefaultParser;
+import org.apache.commons.cli.Options;
+import org.apache.commons.cli.ParseException;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.data.Stat;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+/**
+ * import command for cli
+ */
+public class ImportCommand extends CliCommand {
+
+    private static Options options = new Options();
+    private String[] args;
+    private CommandLine cl;
+
+    static {
+        options.addOption("s", false, "stats");
+        options.addOption("v", true, "version");
+    }
+
+    public ImportCommand() {
+        super("import", "[-s] [-v version] path filepath");
+    }
+
+    @Override
+    public CliCommand parse(String[] cmdArgs) throws CliParseException {
+        CommandLineParser parser = new DefaultParser();
+        try {
+            cl = parser.parse(options, cmdArgs);
+        } catch (ParseException ex) {
+            throw new CliParseException(ex);
+        }
+        args = cl.getArgs();
+        if (args.length < 3) {
+            throw new CliParseException(getUsageStr());
+        }
+
+        return this;
+    }
+
+    @Override
+    public boolean exec() throws CliException {
+        String path = args[1];
+        String filepath = args[2];
+        byte[] data;
+        try {
+            data = Files.readAllBytes(Paths.get(filepath));
+        } catch (IOException ex) {
+            throw new CliException("Unable to read data from file \"" + filepath + "\"", ex);
+        }
+        int version;
+        if (cl.hasOption("v")) {
+            version = Integer.parseInt(cl.getOptionValue("v"));
+        } else {
+            version = -1;
+        }
+
+        try {
+            Stat stat = zk.setData(path, data, version);
+            if (cl.hasOption("s")) {
+                new StatPrinter(out).print(stat);
+            }
+        } catch (IllegalArgumentException ex) {
+            throw new MalformedPathException(ex.getMessage());
+        } catch (KeeperException|InterruptedException ex) {
+            throw new CliWrapperException(ex);
+        }
+        return false;
+    }
+}