chore(js): create-llama express app example (#128)

Co-authored-by: Mikyo King <[email protected]>
Co-authored-by: Alexander Song <[email protected]>

.gitignore

@@ -20,3 +20,7 @@ sdist
 
 # version.ts file is automatically generated at compile time
 version.ts
+
+# Local caching and environment files
+.env
+.vercel

js/examples/llama-index-express/README.md

@@ -0,0 +1,18 @@
+This is a [LlamaIndex](https://www.llamaindex.ai/) project bootstrapped with [`create-llama`](https://github.com/run-llama/LlamaIndexTS/tree/main/packages/create-llama).
+
+## Getting Started
+
+First, startup the backend as described in the [backend README](./backend/README.md).
+
+Second, run the development server of the frontend as described in the [frontend README](./frontend/README.md).
+
+Open [http://localhost:3000](http://localhost:3000) with your browser to see the result.
+
+## Learn More
+
+To learn more about LlamaIndex, take a look at the following resources:
+
+- [LlamaIndex Documentation](https://docs.llamaindex.ai) - learn about LlamaIndex (Python features).
+- [LlamaIndexTS Documentation](https://ts.llamaindex.ai) - learn about LlamaIndex (Typescript features).
+
+You can check out [the LlamaIndexTS GitHub repository](https://github.com/run-llama/LlamaIndexTS) - your feedback and contributions are welcome!

js/examples/llama-index-express/backend/.eslintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "eslint:recommended"
+}

js/examples/llama-index-express/backend/.gitignore

@@ -0,0 +1 @@
+

js/examples/llama-index-express/backend/README.md

@@ -0,0 +1,50 @@
+This is a [LlamaIndex](https://www.llamaindex.ai/) project using [Express](https://expressjs.com/) bootstrapped with [`create-llama`](https://github.com/run-llama/LlamaIndexTS/tree/main/packages/create-llama).
+
+## Getting Started
+
+First, install the dependencies:
+
+```
+npm install
+```
+
+Second, run the development server:
+
+```
+npm run dev
+```
+
+Then call the express API endpoint `/api/chat` to see the result:
+
+```
+curl --location 'localhost:8000/api/chat' \
+--header 'Content-Type: text/plain' \
+--data '{ "messages": [{ "role": "user", "content": "Hello" }] }'
+```
+
+You can start editing the API by modifying `src/controllers/chat.controller.ts`. The endpoint auto-updates as you save the file.
+
+## Production
+
+First, build the project:
+
+```
+npm run build
+```
+
+You can then run the production server:
+
+```
+NODE_ENV=production npm run start
+```
+
+> Note that the `NODE_ENV` environment variable is set to `production`. This disables CORS for all origins.
+
+## Learn More
+
+To learn more about LlamaIndex, take a look at the following resources:
+
+- [LlamaIndex Documentation](https://docs.llamaindex.ai) - learn about LlamaIndex (Python features).
+- [LlamaIndexTS Documentation](https://ts.llamaindex.ai) - learn about LlamaIndex (Typescript features).
+
+You can check out [the LlamaIndexTS GitHub repository](https://github.com/run-llama/LlamaIndexTS) - your feedback and contributions are welcome!

js/examples/llama-index-express/backend/index.ts

@@ -0,0 +1,41 @@
+/* eslint-disable no-console */
+import cors from "cors";
+import "dotenv/config";
+import express, { Express, Request, Response } from "express";
+import chatRouter from "./src/routes/chat.route";
+
+const app: Express = express();
+const port = parseInt(process.env.PORT || "8000");
+
+const env = process.env["NODE_ENV"];
+const isDevelopment = !env || env === "development";
+const prodCorsOrigin = process.env["PROD_CORS_ORIGIN"];
+
+app.use(express.json());
+
+if (isDevelopment) {
+  console.warn("Running in development mode - allowing CORS for all origins");
+  app.use(cors());
+} else if (prodCorsOrigin) {
+  console.log(
+    `Running in production mode - allowing CORS for domain: ${prodCorsOrigin}`,
+  );
+  const corsOptions = {
+    origin: prodCorsOrigin, // Restrict to production domain
+  };
+  app.use(cors(corsOptions));
+} else {
+  console.warn("Production CORS origin not set, defaulting to no CORS.");
+}
+
+app.use(express.text());
+
+app.get("/", (req: Request, res: Response) => {
+  res.send("LlamaIndex Express Server");
+});
+
+app.use("/api/chat", chatRouter);
+
+app.listen(port, () => {
+  console.log(`⚡️[server]: Server is running at http://localhost:${port}`);
+});

js/examples/llama-index-express/backend/instrumentation.ts

@@ -0,0 +1,38 @@
+/* eslint-disable no-console */
+import { registerInstrumentations } from "@opentelemetry/instrumentation";
+import { OpenAIInstrumentation } from "@arizeai/openinference-instrumentation-openai";
+import {
+  ConsoleSpanExporter,
+  SimpleSpanProcessor,
+} from "@opentelemetry/sdk-trace-base";
+import { NodeTracerProvider } from "@opentelemetry/sdk-trace-node";
+import { Resource } from "@opentelemetry/resources";
+import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-proto";
+import { SemanticResourceAttributes } from "@opentelemetry/semantic-conventions";
+import { diag, DiagConsoleLogger, DiagLogLevel } from "@opentelemetry/api";
+
+// For troubleshooting, set the log level to DiagLogLevel.DEBUG
+diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.DEBUG);
+
+const provider = new NodeTracerProvider({
+  resource: new Resource({
+    [SemanticResourceAttributes.SERVICE_NAME]: "openai-service",
+  }),
+});
+
+provider.addSpanProcessor(new SimpleSpanProcessor(new ConsoleSpanExporter()));
+provider.addSpanProcessor(
+  new SimpleSpanProcessor(
+    new OTLPTraceExporter({
+      url: "http://localhost:6006/v1/traces",
+    }),
+  ),
+);
+
+registerInstrumentations({
+  instrumentations: [new OpenAIInstrumentation({})],
+});
+
+provider.register();
+
+console.log("👀 OpenInference initialized");