Spawn controller processes from a different directory on macOS (#47013)

This is the Java side of https://github.com/elastic/ml-cpp/pull/593
with a fallback so that ml-cpp bundles with either the
new or old directory structure work for the time being.
A few days after merging the C++ changes a followup to
this change will be made that removes the fallback.

distribution/build.gradle

@@ -280,8 +280,9 @@ configure(subprojects.findAll { ['archives', 'packages'].contains(it.name) }) {
     modulesFiles = { oss, platform ->
       copySpec {
         eachFile {
-          if (it.relativePath.segments[-2] == 'bin') {
+          if (it.relativePath.segments[-2] == 'bin' || (platform == 'darwin' && it.relativePath.segments[-2] == 'MacOS')) {
             // bin files, wherever they are within modules (eg platform specific) should be executable
+            // and MacOS is an alternative to bin on macOS
             it.mode = 0755
           } else {
             it.mode = 0644

distribution/tools/plugin-cli/src/main/java/org/elasticsearch/plugins/InstallPluginCommand.java

@@ -23,6 +23,7 @@ import joptsimple.OptionSet;
 import joptsimple.OptionSpec;
 import org.apache.lucene.search.spell.LevenshteinDistance;
 import org.apache.lucene.util.CollectionUtil;
+import org.apache.lucene.util.Constants;
 import org.bouncycastle.bcpg.ArmoredInputStream;
 import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider;
 import org.bouncycastle.openpgp.PGPException;
@@ -836,7 +837,10 @@ class InstallPluginCommand extends EnvironmentAwareCommand {
         Files.walkFileTree(destination, new SimpleFileVisitor<Path>() {
             @Override
             public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException {
-                if ("bin".equals(file.getParent().getFileName().toString())) {
+                final String parentDirName = file.getParent().getFileName().toString();
+                if ("bin".equals(parentDirName)
+                    // "MacOS" is an alternative to "bin" on macOS
+                    || (Constants.MAC_OS_X && "MacOS".equals(parentDirName))) {
                     setFileAttributes(file, BIN_FILES_PERMS);
                 } else {
                     setFileAttributes(file, PLUGIN_FILES_PERMS);

qa/no-bootstrap-tests/src/test/java/org/elasticsearch/bootstrap/SpawnerNoBootstrapTests.java

@@ -68,7 +68,7 @@ public class SpawnerNoBootstrapTests extends LuceneTestCase {
     /**
      * Simplest case: a module with no controller daemon.
      */
-    public void testNoControllerSpawn() throws IOException, InterruptedException {
+    public void testNoControllerSpawn() throws IOException {
         Path esHome = createTempDir().resolve("esHome");
         Settings.Builder settingsBuilder = Settings.builder();
         settingsBuilder.put(Environment.PATH_HOME_SETTING.getKey(), esHome.toString());

server/src/main/java/org/elasticsearch/bootstrap/Spawner.java

@@ -72,9 +72,13 @@ final class Spawner implements Closeable {
         List<Path> paths = PluginsService.findPluginDirs(environment.modulesFile());
         for (final Path modules : paths) {
             final PluginInfo info = PluginInfo.readFromProperties(modules);
-            final Path spawnPath = Platforms.nativeControllerPath(modules);
+            Path spawnPath = Platforms.nativeControllerPath(modules);
             if (!Files.isRegularFile(spawnPath)) {
-                continue;
+                // TODO: remove before release and just continue if the controller is not in the standard place
+                spawnPath = Platforms.fallbackNativeControllerPath(modules);
+                if (spawnPath == null || Files.isRegularFile(spawnPath) == false) {
+                    continue;
+                }
             }
             if (!info.hasNativeController()) {
                 final String message = String.format(

server/src/main/java/org/elasticsearch/plugins/Platforms.java

@@ -38,6 +38,15 @@ public class Platforms {
      * The path to the native controller for a plugin with native components.
      */
     public static Path nativeControllerPath(Path plugin) {
+        if (Constants.MAC_OS_X) {
+            return plugin
+                .resolve("platform")
+                .resolve(PLATFORM_NAME)
+                .resolve(PROGRAM_NAME + ".app")
+                .resolve("Contents")
+                .resolve("MacOS")
+                .resolve(PROGRAM_NAME);
+        }
         return plugin
                 .resolve("platform")
                 .resolve(PLATFORM_NAME)
@@ -46,7 +55,26 @@ public class Platforms {
     }
 
     /**
-     * Return the platform name based on the OS name and
+     * The fallback path to the native controller for a plugin with native
+     * components to be used if no program is found using the standard path.
+     * This is a temporary measure to allow developers not working on this
+     * functionality to continue to work with C++ bundles from before or
+     * after the change. This code should never be in a supported release.
+     * TODO: remove this method before release
+     */
+    public static Path fallbackNativeControllerPath(Path plugin) {
+        if (Constants.MAC_OS_X) {
+            return plugin
+                .resolve("platform")
+                .resolve(PLATFORM_NAME)
+                .resolve("bin")
+                .resolve(PROGRAM_NAME);
+        }
+        return null;
+    }
+
+    /**
+     * Return the platform name based on the OS name and architecture, for example:
      * - darwin-x86_64
      * - linux-x86-64
      * - windows-x86_64

server/src/test/java/org/elasticsearch/plugins/PlatformsTests.java

@@ -0,0 +1,47 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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.elasticsearch.plugins;
+
+import org.apache.lucene.util.Constants;
+import org.elasticsearch.test.ESTestCase;
+
+import java.nio.file.Path;
+
+public class PlatformsTests extends ESTestCase {
+
+    public void testNativeControllerPath() {
+
+        final Path nativeControllerPath = Platforms.nativeControllerPath(createTempDir());
+
+        // The directory structure on macOS must match Apple's .app
+        // structure or Gatekeeper may refuse to run the program
+        if (Constants.MAC_OS_X) {
+            String programName = nativeControllerPath.getFileName().toString();
+            Path binDirectory = nativeControllerPath.getParent();
+            assertEquals("MacOS", binDirectory.getFileName().toString());
+            Path contentsDirectory = binDirectory.getParent();
+            assertEquals("Contents", contentsDirectory.getFileName().toString());
+            Path appDirectory = contentsDirectory.getParent();
+            assertEquals(programName + ".app", appDirectory.getFileName().toString());
+        } else {
+            Path binDirectory = nativeControllerPath.getParent();
+            assertEquals("bin", binDirectory.getFileName().toString());
+        }
+    }
+}