HDDS-12519. Generate auto-complete script for Ozone commands.

hadoop-ozone/dist/src/shell/ozone/ozone

@@ -37,6 +37,7 @@ function ozone_usage
   ozone_add_option "--validate (continue)" "validates if all jars as indicated in the corresponding OZONE_RUN_ARTIFACT_NAME classpath file are present, command execution shall continue post validation failure if 'continue' is passed"
 
   ozone_add_subcommand "classpath" client "prints the class path needed for running ozone commands"
+  ozone_add_subcommand "completion" client "generate autocompletion script for bash/zsh"
   ozone_add_subcommand "datanode" daemon "run a HDDS datanode"
   ozone_add_subcommand "envvars" client "display computed Hadoop environment variables"
   ozone_add_subcommand "daemonlog" admin "get/set the log level for each daemon"
@@ -97,6 +98,10 @@ function ozonecmd_case
         exit -1
       fi
     ;;
+    completion)
+      OZONE_CLASSNAME=org.apache.hadoop.ozone.utils.AutoCompletion;
+      OZONE_RUN_ARTIFACT_NAME="ozone-tools"
+    ;;
     datanode)
       OZONE_SUBCMD_SUPPORTDAEMONIZATION="true"
       ozone_deprecate_envvar HDDS_DN_OPTS OZONE_DATANODE_OPTS

hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/admin/OzoneAdmin.java

@@ -27,7 +27,6 @@
  * Ozone Admin Command line tool.
  */
 @CommandLine.Command(name = "ozone admin",
-    hidden = true,
     description = "Developer tools for Ozone Admin operations",
     versionProvider = HddsVersionProvider.class,
     mixinStandardHelpOptions = true)

hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/utils/AutoCompletion.java

@@ -0,0 +1,175 @@
+/*
+ * 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.ozone.utils;
+
+import java.util.Objects;
+import org.apache.hadoop.hdds.cli.GenericCli;
+import org.apache.hadoop.hdds.cli.HddsVersionProvider;
+import org.apache.ratis.util.ReflectionUtils;
+import org.reflections.Reflections;
+import picocli.AutoComplete;
+import picocli.CommandLine;
+import picocli.CommandLine.Command;
+import picocli.CommandLine.Option;
+
+/** Tool to generate auto-completion scripts for Ozone CLI. */
+@Command(name = "ozone completion",
+    header = "Generate autocompletion script for the specified shell.",
+    synopsisHeading = "%nUsage: ",
+    description = AutoCompletion.DESCRIPTION,
+    versionProvider = HddsVersionProvider.class,
+    mixinStandardHelpOptions = true)
+public final class AutoCompletion extends GenericCli {
+
+  public static final String DESCRIPTION = "%nThe generated shell code must " +
+      "be evaluated to provide interactive completion of ozone commands. " +
+      "See each sub-command's help for details on how to use the generated script.%n";
+
+  private static final String BASH_DESCRIPTION = "%nTo load completions in your current shell session: %n" +
+      "%n\t source <(ozone completion bash) %n" +
+      "%nTo load completions for every new session automatically, %n" +
+      "add this to your `~/.bash_profile`: %n" +
+      "%n\t eval \"$(ozone completion bash)\" %n";
+
+  private static final String ZSH_DESCRIPTION = "%nTo load completions in your current shell session: %n" +
+      "%n\t source <(ozone completion zsh)%n" +
+      "%nTo load completions for every new session automatically, %n" +
+      "generate a `_ozone` completion script and put it in your `$fpath`: %n" +
+      "%n\t ozone completion zsh > \"$${fpath[1]}/_ozone\" %n";
+
+  private static final String OZONE_COMMAND = "ozone ";
+  private static final int PREFIX_LENGTH = OZONE_COMMAND.length();
+  private static final String[] PACKAGES_TO_SCAN = {
+      "org.apache.hadoop.hdds",
+      "org.apache.hadoop.ozone",
+      "org.apache.ozone",
+  };
+
+  /** Generates bash auto-completion script for Ozone CLI. */
+  @Command(name = "bash",
+      header = "Generate the shell completion code for bash.",
+      synopsisHeading = "%nUsage: ",
+      description = AutoCompletion.BASH_DESCRIPTION,
+      versionProvider = HddsVersionProvider.class,
+      mixinStandardHelpOptions = true)
+  public void bashCompletion() {
+    out().println(getBashCompletion());
+  }
+
+  /** Generates zsh auto-completion script for Ozone CLI. */
+  @Command(name = "zsh",
+      header = "Generate the shell completion code for zsh.",
+      synopsisHeading = "%nUsage: ",
+      description = AutoCompletion.ZSH_DESCRIPTION,
+      versionProvider = HddsVersionProvider.class,
+      mixinStandardHelpOptions = true)
+  public void zshCompletion() {
+    bashCompletion();
+  }
+
+  private String getBashCompletion() {
+    final CommandLine ozone = new CommandLine(new Ozone());
+    for (String pkg : PACKAGES_TO_SCAN) {
+      new Reflections(pkg).getSubTypesOf(GenericCli.class).stream()
+          .map(AutoCompletion::getCommand)
+          .filter(Objects::nonNull)
+          .filter(AutoCompletion::isPublicCommand)
+          .forEach(command -> ozone.addSubcommand(getCommandName(command), command));
+    }
+    return AutoComplete.bash("ozone", ozone);
+  }
+
+  private static CommandLine getCommand(Class<? extends GenericCli> clazz) {
+    CommandLine command = null;
+    try {
+      command = ReflectionUtils.newInstance(clazz).getCmd();
+    } catch (UnsupportedOperationException ignored) {
+      // Skip the GenericCli subclasses that do not have no-args constructor.
+    }
+    return command;
+  }
+
+  private static boolean isPublicCommand(CommandLine command) {
+    final CommandLine.Model.CommandSpec spec = command.getCommandSpec();
+    return !spec.usageMessage().hidden() &&
+      !CommandLine.Model.CommandSpec.DEFAULT_COMMAND_NAME.equals(spec.name());
+  }
+
+  private static String getCommandName(CommandLine command) {
+    final CommandLine.Model.CommandSpec spec = command.getCommandSpec();
+    final String qualifiedName = spec.qualifiedName();
+    return qualifiedName.startsWith(OZONE_COMMAND) ?
+      qualifiedName.substring(PREFIX_LENGTH) : qualifiedName;
+  }
+
+  public static void main(String[] args) {
+    new AutoCompletion().run(args);
+  }
+
+  /** Ozone top level command, used only to generate auto-complete. */
+  @Command(name = "ozone",
+      description = "Ozone top level command")
+  private static final class Ozone {
+
+    @Option(names = {"--buildpaths"},
+        description = "attempt to add class files from build tree")
+    private String buildpaths;
+
+    @Option(names = {"--config"},
+        description = "Ozone config directory")
+    private String config;
+
+    @Option(names = {"--debug"},
+        description = "turn on shell script debug mode")
+    private String debug;
+
+    @Option(names = {"--daemon"},
+        description = "attempt to add class files from build tree")
+    private String daemon;
+
+    @Option(names = {"--help"},
+        description = "usage information")
+    private String help;
+
+    @Option(names = {"--hostnames"},
+        description = "hosts to use in worker mode")
+    private String hostnames;
+
+    @Option(names = {"--hosts"},
+        description = "list of hosts to use in worker mode")
+    private String hosts;
+
+    @Option(names = {"--loglevel"},
+        description = "set the log4j level for this command")
+    private String loglevel;
+
+    @Option(names = {"--workers"},
+        description = "turn on worker mode")
+    private String workers;
+
+    @Option(names = {"--jvmargs"},
+        description = "append JVM options to any existing options defined in the OZONE_OPTS environment variable. " +
+            "Any defined in OZONE_CLIENT_OPTS will be appended after these jvmargs")
+    private String jvmargs;
+
+    @Option(names = {"--validate"},
+        description = "validates if all jars as indicated in the corresponding OZONE_RUN_ARTIFACT_NAME classpath " +
+            "file are present, command execution shall continue post validation failure if 'continue' is passed")
+    private String validate;
+  }
+}