MLE-25666 Deferring construction of DatabaseClient

This is just scratching the surface - next step will be to modify GenericFileLoader to accept a DatabaseClientSupplier instead of a DatabaseClient. That will allow the commands for loading modules, data, and schemas to only construct a client when necessary instead of eagerly.

Author: rjrudin

ml-app-deployer/src/main/java/com/marklogic/appdeployer/command/modules/LoadModulesCommand.java

@@ -62,16 +62,13 @@ protected void loadModulesIntoMainServer(CommandContext context) {
 		}
 
 		AppConfig config = context.getAppConfig();
-		DatabaseClient client = config.newDatabaseClient();
 
 		final List<String> pathsList = config.getModulePaths();
 		final String[] pathsArray = pathsList.toArray(new String[]{});
 
-		try {
-			logger.info("Loading modules from paths: " + pathsList);
+		try (DatabaseClient client = config.newDatabaseClient()) {
+			logger.info("Loading modules from paths: {}", pathsList);
 			modulesLoader.loadModules(client, new DefaultModulesFinder(), pathsArray);
-		} finally {
-			client.release();
 		}
 	}
 

ml-app-deployer/src/main/java/com/marklogic/appdeployer/command/plugins/InstallPluginsCommand.java

@@ -8,6 +8,7 @@
 import com.marklogic.appdeployer.command.AbstractUndoableCommand;
 import com.marklogic.appdeployer.command.CommandContext;
 import com.marklogic.appdeployer.command.SortOrderConstants;
+import com.marklogic.client.ext.helper.DatabaseClientSupplier;
 import com.marklogic.client.DatabaseClient;
 import com.marklogic.client.document.BinaryDocumentManager;
 import com.marklogic.client.eval.ServerEvaluationCall;
@@ -39,9 +40,10 @@ public void execute(CommandContext context) {
 			return;
 		}
 
-		DatabaseClient client = determineDatabaseClient(context.getAppConfig());
-		for (String path : paths) {
-			installPluginsInPath(path, context.getAppConfig(), client);
+		try (DatabaseClientSupplier clientSupplier = new DatabaseClientSupplier(() -> determineDatabaseClient(context.getAppConfig()))) {
+			for (String path : paths) {
+				installPluginsInPath(path, context.getAppConfig(), clientSupplier);
+			}
 		}
 	}
 
@@ -52,9 +54,10 @@ public void undo(CommandContext context) {
 			return;
 		}
 
-		DatabaseClient client = determineDatabaseClient(context.getAppConfig());
-		for (String path : paths) {
-			uninstallPluginsInPath(path, context.getAppConfig(), client);
+		try (DatabaseClientSupplier clientSupplier = new DatabaseClientSupplier(() -> determineDatabaseClient(context.getAppConfig()))) {
+			for (String path : paths) {
+				uninstallPluginsInPath(path, context.getAppConfig(), clientSupplier);
+			}
 		}
 	}
 
@@ -72,7 +75,7 @@ protected List<String> getPluginPaths(CommandContext context) {
 		return config.getPluginPaths();
 	}
 
-	protected void installPluginsInPath(String path, AppConfig appConfig, DatabaseClient client) {
+	protected void installPluginsInPath(String path, AppConfig appConfig, DatabaseClientSupplier clientSupplier) {
 		File pluginsDir = new File(path);
 		if (pluginsDir == null || !pluginsDir.exists()) {
 			return;
@@ -86,9 +89,9 @@ protected void installPluginsInPath(String path, AppConfig appConfig, DatabaseCl
 				}
 
 				makePlugin(dir, appConfig);
-				final String binaryUri = insertPluginZip(dir, appConfig, client);
+				final String binaryUri = insertPluginZip(dir, appConfig, clientSupplier.get());
 				if (binaryUri != null) {
-					installPlugin(binaryUri, appConfig, client);
+					installPlugin(binaryUri, appConfig, clientSupplier.get());
 				}
 			}
 		}
@@ -151,7 +154,7 @@ protected void installPlugin(String uri, AppConfig appConfig, DatabaseClient cli
 		logger.info(format("Installed plugin with scope '%s', result: %s", scope, result));
 	}
 
-	protected void uninstallPluginsInPath(String path, AppConfig appConfig, DatabaseClient client) {
+	protected void uninstallPluginsInPath(String path, AppConfig appConfig, DatabaseClientSupplier clientSupplier) {
 		File pluginsDir = new File(path);
 		if (pluginsDir == null || !pluginsDir.exists()) {
 			return;
@@ -166,15 +169,15 @@ protected void uninstallPluginsInPath(String path, AppConfig appConfig, Database
 
 				final String pluginName = getPluginName(file, appConfig);
 				if (pluginName != null) {
-					uninstallPlugin(pluginName, appConfig, client);
+					uninstallPlugin(pluginName, appConfig, clientSupplier.get());
 				}
 			}
 		}
 	}
 
 	protected String getPluginName(File dir, AppConfig appConfig) {
 		File manifestFile = new File(dir, "manifest.xml");
-		if (manifestFile == null || !manifestFile.exists()) {
+		if (!manifestFile.exists()) {
 			// Need to make the plugin so the metadata file is guaranteed to exist
 			makePlugin(dir, appConfig);
 			manifestFile = new File(dir, "manifest.xml");

ml-app-deployer/src/main/java/com/marklogic/appdeployer/command/security/InsertCertificateHostsTemplateCommand.java

@@ -37,10 +37,12 @@ public InsertCertificateHostsTemplateCommand() {
 
 	@Override
 	public void execute(CommandContext context) {
+		// A query has to be made to MarkLogic here to get the list of certificate template names, because otherwise,
+		// we don't know what template names to look for in the user's project directory.
 		List<String> templateNames = new CertificateTemplateManager(context.getManageClient()).getAsXml().getListItemNameRefs();
 		if (templateNames != null && !templateNames.isEmpty()) {
 			if (logger.isInfoEnabled()) {
-				logger.info("Looking for host certificates to insert for certificate templates: " + templateNames);
+				logger.info("Looking for host certificates to insert for certificate templates: {}", templateNames);
 			}
 			for (String templateName : templateNames) {
 				insertHostCertificatesForTemplate(context, templateName);

ml-javaclient-util/src/main/java/com/marklogic/client/ext/helper/DatabaseClientSupplier.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2015-2025 Progress Software Corporation and/or its subsidiaries or affiliates. All Rights Reserved.
+ */
+package com.marklogic.client.ext.helper;
+
+import com.marklogic.client.DatabaseClient;
+
+import java.io.Closeable;
+import java.util.function.Supplier;
+
+/**
+ * Preferred mechanism for lazy instantiation of a DatabaseClient. Will eventually deprecate DatabaseClientProvider in
+ * favor of this.
+ *
+ * @since 6.2.0
+ */
+public class DatabaseClientSupplier implements Closeable, Supplier<DatabaseClient> {
+
+	private DatabaseClient databaseClient;
+	private final Supplier<DatabaseClient> databaseClientSupplier;
+
+	/**
+	 * @param databaseClientSupplier delegates construction of the client to the given supplier. Will then hold onto
+	 *                               an instance of the client after it's created so that it's only created once.
+	 */
+	public DatabaseClientSupplier(Supplier<DatabaseClient> databaseClientSupplier) {
+		this.databaseClientSupplier = databaseClientSupplier;
+	}
+
+	public DatabaseClient get() {
+		if (databaseClient == null) {
+			databaseClient = databaseClientSupplier.get();
+		}
+		return databaseClient;
+	}
+
+	@Override
+	public void close() {
+		if (databaseClient != null) {
+			databaseClient.close();
+		}
+	}
+}