Merge pull request #46 from schemacrawler/mcpserver

Create a new plugin to start the SchemaCrawler MCP server

Author: sualeh

schemacrawler-ai-mcp/src/main/java/schemacrawler/tools/command/aichat/mcp/ConnectionService.java

@@ -0,0 +1,79 @@
+package schemacrawler.tools.command.aichat.mcp;
+
+import schemacrawler.schema.Catalog;
+
+import java.sql.Connection;
+
+import static java.util.Objects.requireNonNull;
+
+/**
+ * A singleton service that provides access to database connection resources. This class follows an
+ * initialization-on-demand pattern where the service must be explicitly initialized once before it
+ * can be used.
+ */
+public class ConnectionService {
+
+  private static final Object lock = new Object();
+  private static volatile ConnectionService connectionService;
+  private final Catalog catalog;
+  private final Connection connection;
+  private final McpServerCommandOptions options;
+
+  /**
+   * Private constructor to prevent direct instantiation. Use {@link
+   * #instantiate(McpServerCommandOptions, Catalog, Connection)} to initialize and {@link
+   * #getInstance()} to access the singleton instance.
+   */
+  private ConnectionService(
+      final McpServerCommandOptions options, final Catalog catalog, final Connection connection) {
+    this.catalog = requireNonNull(catalog, "No catalog provided");
+    this.connection = requireNonNull(connection, "No connection provided");
+    this.options = requireNonNull(options, "No options provided");
+  }
+
+  /**
+   * Initializes the ConnectionService singleton. This method should be called exactly once during
+   * application startup. Subsequent calls will throw an IllegalStateException.
+   *
+   * @param options Command options
+   * @param catalog Database schema catalog
+   * @param connection SQL connection
+   * @throws IllegalStateException if the service has already been initialized
+   */
+  public static void instantiate(
+      final McpServerCommandOptions options, final Catalog catalog, final Connection connection) {
+    synchronized (lock) {
+      if (connectionService != null) {
+        throw new IllegalStateException("ConnectionService has already been initialized");
+      }
+      connectionService = new ConnectionService(options, catalog, connection);
+    }
+  }
+
+  /**
+   * Gets the singleton instance of ConnectionService. The service must have been initialized with
+   * {@link #instantiate(McpServerCommandOptions, Catalog, Connection)} before this method is
+   * called.
+   *
+   * @return The singleton ConnectionService instance
+   * @throws IllegalStateException if the service has not been initialized
+   */
+  public static ConnectionService getInstance() {
+    if (connectionService == null) {
+      throw new IllegalStateException("ConnectionService has not been initialized yet");
+    }
+    return connectionService;
+  }
+
+  public Catalog catalog() {
+    return catalog;
+  }
+
+  public Connection connection() {
+    return connection;
+  }
+
+  public McpServerCommandOptions options() {
+    return options;
+  }
+}

schemacrawler-ai-mcp/src/main/java/schemacrawler/tools/command/aichat/mcp/McpServerCommand.java

@@ -0,0 +1,66 @@
+/*
+========================================================================
+SchemaCrawler
+http://www.schemacrawler.com
+Copyright (c) 2000-2025, Sualeh Fatehi <sualeh@hotmail.com>.
+All rights reserved.
+------------------------------------------------------------------------
+
+SchemaCrawler is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+SchemaCrawler and the accompanying materials are made available under
+the terms of the Eclipse Public License v1.0, GNU General Public License
+v3 or GNU Lesser General Public License v3.
+
+You may elect to redistribute this code under any of these licenses.
+
+The Eclipse Public License is available at:
+http://www.eclipse.org/legal/epl-v10.html
+
+The GNU General Public License v3 and the GNU Lesser General Public
+License v3 are available at:
+http://www.gnu.org/licenses/
+
+========================================================================
+*/
+
+package schemacrawler.tools.command.aichat.mcp;
+
+import schemacrawler.tools.executable.BaseSchemaCrawlerCommand;
+import us.fatehi.utility.property.PropertyName;
+
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/** SchemaCrawler command plug-in. */
+public final class McpServerCommand extends BaseSchemaCrawlerCommand<McpServerCommandOptions> {
+
+  private static final Logger LOGGER = Logger.getLogger(McpServerCommand.class.getName());
+
+  static final PropertyName COMMAND =
+      new PropertyName("mcpserver", "Allow AI agents access to your schema");
+
+  protected McpServerCommand() {
+    super(COMMAND);
+  }
+
+  @Override
+  public void checkAvailability() throws RuntimeException {
+    LOGGER.log(Level.FINE, "No checks required for MCP server");
+  }
+
+  @Override
+  public void execute() {
+    LOGGER.log(Level.FINE, "Starting MCP server");
+    ConnectionService.instantiate(commandOptions, catalog, connection);
+    SchemaCrawlerMcpServer.start();
+  }
+
+  @Override
+  public boolean usesConnection() {
+    // Support commands that use connections
+    return true;
+  }
+}

schemacrawler-ai-mcp/src/main/java/schemacrawler/tools/command/aichat/mcp/McpServerCommandOptions.java

@@ -0,0 +1,45 @@
+/*
+========================================================================
+SchemaCrawler
+http://www.schemacrawler.com
+Copyright (c) 2000-2025, Sualeh Fatehi <sualeh@hotmail.com>.
+All rights reserved.
+------------------------------------------------------------------------
+
+SchemaCrawler is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+SchemaCrawler and the accompanying materials are made available under
+the terms of the Eclipse Public License v1.0, GNU General Public License
+v3 or GNU Lesser General Public License v3.
+
+You may elect to redistribute this code under any of these licenses.
+
+The Eclipse Public License is available at:
+http://www.eclipse.org/legal/epl-v10.html
+
+The GNU General Public License v3 and the GNU Lesser General Public
+License v3 are available at:
+http://www.gnu.org/licenses/
+
+========================================================================
+*/
+
+package schemacrawler.tools.command.aichat.mcp;
+
+import schemacrawler.tools.executable.CommandOptions;
+
+
+public record McpServerCommandOptions() implements CommandOptions {
+
+  public McpServerCommandOptions {
+    // No options for this command
+  }
+
+  @Override
+  public String toString() {
+    // No options for this command
+    return this.getClass().getName();
+  }
+}

schemacrawler-ai-mcp/src/main/java/schemacrawler/tools/command/aichat/mcp/McpServerCommandOptionsBuilder.java

@@ -0,0 +1,70 @@
+/*
+========================================================================
+SchemaCrawler
+http://www.schemacrawler.com
+Copyright (c) 2000-2025, Sualeh Fatehi <sualeh@hotmail.com>.
+All rights reserved.
+------------------------------------------------------------------------
+
+SchemaCrawler is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+SchemaCrawler and the accompanying materials are made available under
+the terms of the Eclipse Public License v1.0, GNU General Public License
+v3 or GNU Lesser General Public License v3.
+
+You may elect to redistribute this code under any of these licenses.
+
+The Eclipse Public License is available at:
+http://www.eclipse.org/legal/epl-v10.html
+
+The GNU General Public License v3 and the GNU Lesser General Public
+License v3 are available at:
+http://www.gnu.org/licenses/
+
+========================================================================
+*/
+
+package schemacrawler.tools.command.aichat.mcp;
+
+import schemacrawler.schemacrawler.OptionsBuilder;
+import schemacrawler.tools.options.Config;
+import schemacrawler.tools.options.ConfigOptionsBuilder;
+
+
+public final class McpServerCommandOptionsBuilder
+    implements OptionsBuilder<McpServerCommandOptionsBuilder, McpServerCommandOptions>,
+        ConfigOptionsBuilder<McpServerCommandOptionsBuilder, McpServerCommandOptions> {
+
+  public static McpServerCommandOptionsBuilder builder() {
+    return new McpServerCommandOptionsBuilder();
+  }
+
+  private McpServerCommandOptionsBuilder() {
+    // No options for this command
+  }
+
+  @Override
+  public McpServerCommandOptionsBuilder fromConfig(final Config config) {
+    // No options for this command
+    return this;
+  }
+
+  @Override
+  public McpServerCommandOptionsBuilder fromOptions(final McpServerCommandOptions options) {
+    // No options for this command
+    return this;
+  }
+
+  @Override
+  public Config toConfig() {
+    // No options for this command
+    return new Config();
+  }
+
+  @Override
+  public McpServerCommandOptions toOptions() {
+    return new McpServerCommandOptions();
+  }
+}

schemacrawler-ai-mcp/src/main/java/schemacrawler/tools/command/aichat/mcp/McpServerCommandProvider.java

@@ -0,0 +1,73 @@
+/*
+========================================================================
+SchemaCrawler
+http://www.schemacrawler.com
+Copyright (c) 2000-2025, Sualeh Fatehi <sualeh@hotmail.com>.
+All rights reserved.
+------------------------------------------------------------------------
+
+SchemaCrawler is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+SchemaCrawler and the accompanying materials are made available under
+the terms of the Eclipse Public License v1.0, GNU General Public License
+v3 or GNU Lesser General Public License v3.
+
+You may elect to redistribute this code under any of these licenses.
+
+The Eclipse Public License is available at:
+http://www.eclipse.org/legal/epl-v10.html
+
+The GNU General Public License v3 and the GNU Lesser General Public
+License v3 are available at:
+http://www.gnu.org/licenses/
+
+========================================================================
+*/
+
+package schemacrawler.tools.command.aichat.mcp;
+
+import static schemacrawler.tools.executable.commandline.PluginCommand.newPluginCommand;
+import schemacrawler.schemacrawler.exceptions.ExecutionRuntimeException;
+import schemacrawler.tools.executable.BaseCommandProvider;
+import schemacrawler.tools.executable.commandline.PluginCommand;
+import schemacrawler.tools.options.Config;
+import schemacrawler.tools.options.OutputOptions;
+
+/** SchemaCrawler command plug-in for AI chat. */
+public final class McpServerCommandProvider extends BaseCommandProvider {
+
+  public McpServerCommandProvider() {
+    super(McpServerCommand.COMMAND);
+  }
+
+  @Override
+  public PluginCommand getCommandLineCommand() {
+    final PluginCommand pluginCommand = newPluginCommand(McpServerCommand.COMMAND);
+    return pluginCommand;
+  }
+
+  @Override
+  public McpServerCommand newSchemaCrawlerCommand(final String command, final Config config) {
+    if (!supportsCommand(command)) {
+      throw new IllegalArgumentException("Cannot support command, " + command);
+    }
+
+    try {
+      final McpServerCommandOptions options =
+          McpServerCommandOptionsBuilder.builder().fromConfig(config).toOptions();
+
+      final McpServerCommand scCommand = new McpServerCommand();
+      scCommand.configure(options);
+      return scCommand;
+    } catch (final Exception e) {
+      throw new ExecutionRuntimeException(e);
+    }
+  }
+
+  @Override
+  public boolean supportsOutputFormat(final String command, final OutputOptions outputOptions) {
+    return true;
+  }
+}

schemacrawler-ai-mcp/src/main/java/schemacrawler/tools/command/aichat/mcp/SchemaCrawlerMCPServer.java

@@ -0,0 +1,23 @@
+package schemacrawler.tools.command.aichat.mcp;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+
+
+/**
+ * Spring Boot application for the SchemaCrawler AI MCP server. This class enables the Spring AI MCP
+ * server capabilities.
+ */
+@SpringBootApplication
+public class SchemaCrawlerMcpServer {
+
+  public static void main(final String[] args) {
+    SpringAIUtility.isDryRun = true;
+    start();
+  }
+
+  public static void start() {
+    SpringApplication.run(SchemaCrawlerMcpServer.class);
+  }
+}