Initial boilerplate for implementing the upgrade cli.

Signed-off-by: Rabi Panda <adnapibar@gmail.com>

distribution/build.gradle

@@ -268,7 +268,7 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
    *             Properties to expand when copying packaging files             *
    *****************************************************************************/
   configurations {
-    ['libs', 'libsPluginCli', 'libsKeystoreCli', 'libsSecurityCli'].each {
+    ['libs', 'libsPluginCli', 'libsKeystoreCli', 'libsSecurityCli', 'libsUpgradeCli'].each {
       create(it) {
         canBeConsumed = false
         canBeResolved = true
@@ -289,6 +289,7 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
 
     libsPluginCli project(':distribution:tools:plugin-cli')
     libsKeystoreCli project(path: ':distribution:tools:keystore-cli')
+    libsUpgradeCli project(path: ':distribution:tools:upgrade-cli')
   }
 
   project.ext {
@@ -306,6 +307,9 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
         into('tools/keystore-cli') {
           from(configurations.libsKeystoreCli)
         }
+        into('tools/upgrade-cli') {
+          from(configurations.libsUpgradeCli)
+        }
       }
     }
 

distribution/src/bin/opensearch-upgrade

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+OPENSEARCH_MAIN_CLASS=org.opensearch.upgrade.UpgradeCli \
+  OPENSEARCH_ADDITIONAL_CLASSPATH_DIRECTORIES=lib/tools/upgrade-cli \
+  "`dirname "$0"`"/opensearch-cli \
+  "$@"

distribution/src/bin/opensearch-upgrade.bat

@@ -0,0 +1,16 @@
+@echo off
+
+setlocal enabledelayedexpansion
+setlocal enableextensions
+
+set OPENSEARCH_MAIN_CLASS=org.opensearch.upgrade.UpgradeCli
+set OPENSEARCH_ADDITIONAL_CLASSPATH_DIRECTORIES=lib/tools/upgrade-cli
+call "%~dp0opensearch-cli.bat" ^
+  %%* ^
+  || goto exit
+
+
+endlocal
+endlocal
+:exit
+exit /b %ERRORLEVEL%

distribution/tools/upgrade-cli/build.gradle

@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ */
+
+apply plugin: 'opensearch.build'
+
+archivesBaseName = 'opensearch-upgrade-cli'
+
+dependencies {
+  compileOnly project(":server")
+  compileOnly project(":libs:opensearch-cli")
+  testImplementation project(":test:framework")
+  testRuntimeOnly 'com.google.guava:guava:18.0'
+}
+
+test {
+  systemProperty 'tests.security.manager', 'false'
+}

distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/UpgradeCli.java

@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.upgrade;
+
+import org.opensearch.cli.LoggingAwareMultiCommand;
+import org.opensearch.cli.Terminal;
+
+/**
+ * CLI tool for upgrading from a supported Elasticsearch version to
+ * an OpenSearch version.
+ *
+ * - It will autodetect the presence of a running ES server
+ * - If the ES Server is not running, it will need the path to the ES installation.
+ * - Copy the configurations across
+ * - Shutdown the ES server (if running)
+ * - Start the OpenSearch server
+ *
+ */
+public class UpgradeCli extends LoggingAwareMultiCommand {
+    public UpgradeCli() {
+        super("A tool for migrating from a supported Elasticsearch version to an OpenSearch version");
+        subcommands.put("upgrade", new UpgradeToOpenSearchCommand());
+    }
+
+    public static void main(String[] args) throws Exception {
+        exit(new UpgradeCli().main(args, Terminal.DEFAULT));
+    }
+}

distribution/tools/upgrade-cli/src/main/java/org/opensearch/upgrade/UpgradeToOpenSearchCommand.java

@@ -0,0 +1,39 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.upgrade;
+
+import joptsimple.OptionSet;
+import joptsimple.OptionSpec;
+import org.opensearch.cli.EnvironmentAwareCommand;
+import org.opensearch.cli.ExitCodes;
+import org.opensearch.cli.Terminal;
+import org.opensearch.cli.UserException;
+import org.opensearch.env.Environment;
+
+import java.util.List;
+
+public class UpgradeToOpenSearchCommand extends EnvironmentAwareCommand {
+    private final OptionSpec<String> arguments;
+    public UpgradeToOpenSearchCommand() {
+        super("Upgrade to OpenSearch", () -> {
+        });
+        arguments =parser.nonOptions("elasticsearch installation path");
+    }
+
+
+    @Override
+    protected void execute(Terminal terminal, OptionSet options, Environment env) throws Exception {
+        final List<String> argumentValues = arguments.values(options);
+        if (argumentValues.size() != 1) {
+            throw new UserException(ExitCodes.USAGE, "Missing elasticsearch installation location");
+        }
+        terminal.println("Thanks! we're bringing this out soon!!");
+    }
+
+}

settings.gradle

@@ -55,6 +55,7 @@ List projects = [
   'distribution:tools:launchers',
   'distribution:tools:plugin-cli',
   'distribution:tools:keystore-cli',
+  'distribution:tools:upgrade-cli',
   'server',
   'server:cli',
   'test:framework',