Fix/app kit integration without mcp (#17)

* refactor(plugin): conditionally apply databricks client middleware per plugin

* refactor(server): server plugin dont have env deps, already have defaults

* refactor(server): auto detect static path from common build directories

Author: ditadi

apps/dev-playground/server/.env.dist

@@ -1,8 +1,6 @@
 DATABRICKS_HOST=
 DATABRICKS_WAREHOUSE_ID=
 DATABRICKS_WORKSPACE_ID=
-DATABRICKS_APP_PORT=8000
-FLASK_RUN_HOST=0.0.0.0
 NODE_ENV='development'
 OTEL_EXPORTER_OTLP_ENDPOINT='http://localhost:4318'
 OTEL_RESOURCE_ATTRIBUTES='service.sample_attribute=dev'

packages/app-kit/src/analytics/analytics.ts

@@ -20,6 +20,7 @@ import type {
 export class AnalyticsPlugin extends Plugin {
   name = "analytics";
   envVars = [];
+  requiresDatabricksClient = true;
 
   protected static description = "Analytics plugin for data analysis";
   protected declare config: IAnalyticsConfig;

packages/app-kit/src/plugin/plugin.ts

@@ -41,6 +41,9 @@ export abstract class Plugin<
   protected telemetry: ITelemetry;
   protected abstract envVars: string[];
 
+  /** If the plugin requires the Databricks client to be set in the request context */
+  requiresDatabricksClient = false;
+
   static phase: PluginPhase = "normal";
   name: string;
 

packages/app-kit/src/plugin/tests/plugin.test.ts

@@ -571,6 +571,22 @@ describe("Plugin", () => {
     });
   });
 
+  describe("requiresDatabricksClient", () => {
+    test("should default to false", () => {
+      const plugin = new TestPlugin(config);
+      expect(plugin.requiresDatabricksClient).toBe(false);
+    });
+
+    test("should allow plugins to override to true", () => {
+      class PluginWithDatabricksClient extends TestPlugin {
+        requiresDatabricksClient = true;
+      }
+
+      const plugin = new PluginWithDatabricksClient(config);
+      expect(plugin.requiresDatabricksClient).toBe(true);
+    });
+  });
+
   describe("integration scenarios", () => {
     test("should handle complex execution flow with all interceptors", async () => {
       const plugin = new TestPlugin({

packages/app-kit/src/server/index.ts

@@ -16,14 +16,14 @@ dotenv.config({ path: path.resolve(process.cwd(), "./server/.env") });
 export class ServerPlugin extends Plugin {
   public static DEFAULT_CONFIG = {
     autoStart: true,
-    staticPath: path.resolve(process.cwd(), "client", "dist"),
+    staticPath: ServerPlugin.findDefaultStaticPath(),
     host: process.env.FLASK_RUN_HOST || "0.0.0.0",
     port: Number(process.env.DATABRICKS_APP_PORT) || 8000,
     watch: process.env.NODE_ENV === "development",
   };
 
   public name = "server" as const;
-  public envVars = ["DATABRICKS_APP_PORT", "FLASK_RUN_HOST"];
+  public envVars: string[] = [];
   private serverApplication: express.Application;
   private server: HTTPServer | null;
   private devModeManager?: DevModeManager;
@@ -65,9 +65,8 @@ export class ServerPlugin extends Plugin {
 
   async start(): Promise<express.Application> {
     this.serverApplication.use(express.json());
-    this.serverApplication.use(await databricksClientMiddleware());
 
-    this.extendRoutes();
+    await this.extendRoutes();
 
     for (const extension of this.serverExtensions) {
       extension(this.serverApplication);
@@ -156,7 +155,7 @@ export class ServerPlugin extends Plugin {
     return this;
   }
 
-  private extendRoutes() {
+  private async extendRoutes() {
     if (!this.config.plugins) return;
 
     this.serverApplication.get("/health", (_, res) => {
@@ -169,6 +168,10 @@ export class ServerPlugin extends Plugin {
       if (plugin?.injectRoutes && typeof plugin.injectRoutes === "function") {
         const router = express.Router();
 
+        // add databricks client middleware to the router if the plugin needs the request context
+        if (plugin.requiresDatabricksClient)
+          router.use(await databricksClientMiddleware());
+
         plugin.injectRoutes(router);
 
         this.serverApplication.use(`/api/${plugin.name}`, router);
@@ -222,6 +225,17 @@ export class ServerPlugin extends Plugin {
     return configObject;
   }
 
+  private static findDefaultStaticPath() {
+    const staticPaths = ["dist", "client/dist", "build", "public", "out"];
+    const cwd = process.cwd();
+    for (const p of staticPaths) {
+      if (fs.existsSync(path.resolve(cwd, p, "index.html"))) {
+        return path.resolve(cwd, p);
+      }
+    }
+    return undefined;
+  }
+
   private _gracefulShutdown() {
     console.log("Starting graceful shutdown...");
 

packages/app-kit/src/telemetry/telemetry-manager.ts

@@ -66,9 +66,6 @@ export class TelemetryManager {
     if (this.sdk) return;
 
     if (!process.env.OTEL_EXPORTER_OTLP_ENDPOINT) {
-      console.log(
-        "[Telemetry] OTEL_EXPORTER_OTLP_ENDPOINT not set; telemetry disabled",
-      );
       return;
     }