Add support for backend telemetry (tracing & metrics)

Dockerfile

@@ -19,7 +19,7 @@ RUN --mount=type=cache,target=/app/.npm \
 COPY --link --chown=1000 . .
 
 RUN --mount=type=secret,id=DOTENV_LOCAL,dst=.env.local \
-    npm run build
+        npm run build && npm run build -- --config vite.telemetry.config.ts
 
 FROM node:20-slim
 
@@ -29,4 +29,4 @@ COPY --from=builder-production /app/node_modules /app/node_modules
 COPY --link --chown=1000 package.json /app/package.json
 COPY --from=builder /app/build /app/build
 
-CMD pm2 start /app/build/index.js -i $CPU_CORES --no-daemon
+CMD pm2 start /app/build/index.js --node-args="--require /app/build/telemetry.cjs" -i $CPU_CORES --no-daemon

package.json

@@ -5,7 +5,7 @@
 	"packageManager": "[email protected]",
 	"scripts": {
 		"dev": "vite dev",
-		"build": "vite build",
+		"build": "bash scripts/clean-opentelemetry.sh && vite build",
 		"preview": "vite preview",
 		"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
 		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
@@ -53,6 +53,12 @@
 		"@huggingface/hub": "^0.5.1",
 		"@huggingface/inference": "^2.6.3",
 		"@iconify-json/bi": "^1.1.21",
+		"@opentelemetry/api": "^1.8.0",
+		"@opentelemetry/auto-instrumentations-node": "^0.44.0",
+		"@opentelemetry/exporter-metrics-otlp-proto": "^0.50.0",
+		"@opentelemetry/sdk-metrics": "^1.23.0",
+		"@opentelemetry/sdk-node": "^0.50.0",
+		"@opentelemetry/sdk-trace-node": "^1.23.0",
 		"@resvg/resvg-js": "^2.6.0",
 		"@xenova/transformers": "^2.16.1",
 		"autoprefixer": "^10.4.14",

scripts/clean-opentelemetry.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+packages="./node_modules/@opentelemetry/*/package.json"
+
+for file in ${packages}; do
+  sed -i '/"module": "build\/esm\/index\.js",/d' ${file}
+done

src/routes/conversation/+server.ts

@@ -10,6 +10,7 @@ import { defaultEmbeddingModel } from "$lib/server/embeddingModels";
 import { v4 } from "uuid";
 import { authCondition } from "$lib/server/auth";
 import { usageLimits } from "$lib/server/usageLimits";
+import { metrics } from "@opentelemetry/api";
 
 export const POST: RequestHandler = async ({ locals, request }) => {
 	const body = await request.text();
@@ -111,6 +112,15 @@ export const POST: RequestHandler = async ({ locals, request }) => {
 		...(values.fromShare ? { meta: { fromShareId: values.fromShare } } : {}),
 	});
 
+	const meter = metrics.getMeter("chat-ui");
+	const counter = meter.createCounter("chat-ui.conversations.count", {
+		description: "The number of conversations created",
+	});
+	counter.add(1, {
+		"chat-ui.model": values.model,
+		"user.email": locals.user?.email || undefined,
+	});
+
 	return new Response(
 		JSON.stringify({
 			conversationId: res.insertedId.toString(),

src/routes/conversation/[id]/+server.ts

@@ -23,6 +23,7 @@ import { addSibling } from "$lib/utils/tree/addSibling.js";
 import { preprocessMessages } from "$lib/server/preprocessMessages.js";
 import { usageLimits } from "$lib/server/usageLimits";
 import { isURLLocal } from "$lib/server/isURLLocal.js";
+import { metrics } from "@opentelemetry/api";
 
 export async function POST({ request, locals, params, getClientAddress }) {
 	const id = z.string().parse(params.id);
@@ -243,6 +244,15 @@ export async function POST({ request, locals, params, getClientAddress }) {
 			messageId
 		);
 
+		const meter = metrics.getMeter("chat-ui");
+		const counter = meter.createCounter("chat-ui.conversations.messages.count", {
+			description: "The number of user messages created",
+		});
+		counter.add(1, {
+			"chat-ui.model": "values.model",
+			"user.email": locals.user?.email || undefined,
+		});
+
 		messageToWriteToId = addChildren(
 			conv,
 			{

src/telemetry.ts

@@ -0,0 +1,77 @@
+// This file is built outside of sveltekit and cannot import from the rest of the application
+// or special imports like $env/dynamic/private.
+import { NodeSDK } from "@opentelemetry/sdk-node";
+import { getNodeAutoInstrumentations } from "@opentelemetry/auto-instrumentations-node";
+import { PeriodicExportingMetricReader } from "@opentelemetry/sdk-metrics";
+import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-proto";
+import { OTLPMetricExporter } from "@opentelemetry/exporter-metrics-otlp-proto";
+import { SEMRESATTRS_SERVICE_NAME } from "@opentelemetry/semantic-conventions";
+import { AlwaysOnSampler } from "@opentelemetry/sdk-trace-base";
+import { Resource } from "@opentelemetry/resources";
+
+const TRACE_URL =
+	process.env.OTEL_EXPORTER_OTLP_ENDPOINT + "/v1/traces" || "http://localhost:4318/v1/traces";
+const METRICS_URL =
+	process.env.OTEL_EXPORTER_OTLP_ENDPOINT + "/v1/metrics" || "http://localhost:4318/v1/metrics";
+const SERVICE_NAME = process.env.OTEL_SERVICE_NAME || "huggingface/chat-ui";
+
+const exporter = new OTLPTraceExporter({
+	url: TRACE_URL,
+	headers: {},
+});
+
+const otelNodeSdk = new NodeSDK({
+	autoDetectResources: true,
+	serviceName: SERVICE_NAME,
+	traceExporter: exporter,
+	metricReader: new PeriodicExportingMetricReader({
+		exporter: new OTLPMetricExporter({
+			url: METRICS_URL,
+			headers: {},
+		}),
+	}),
+	sampler: new AlwaysOnSampler(),
+	resource: new Resource({
+		[SEMRESATTRS_SERVICE_NAME]: SERVICE_NAME,
+	}),
+	instrumentations: [
+		getNodeAutoInstrumentations({
+			"@opentelemetry/instrumentation-http": {
+				ignoreIncomingRequestHook: (request) => {
+					// Don't trace static asset requests
+					if (
+						request.url?.endsWith(".js") ||
+						request.url?.endsWith(".svg") ||
+						request.url?.endsWith(".css")
+					) {
+						return false;
+					}
+					return true;
+				},
+			},
+		}),
+	],
+});
+
+export class Telemetry {
+	private static instance: Telemetry;
+	private initialized = false;
+
+	private constructor() {}
+
+	public static getInstance(): Telemetry {
+		if (!Telemetry.instance) {
+			Telemetry.instance = new Telemetry();
+		}
+		return Telemetry.instance;
+	}
+
+	public start() {
+		if (!this.initialized) {
+			this.initialized = true;
+			otelNodeSdk.start();
+		}
+	}
+}
+
+Telemetry.getInstance().start();

vite.telemetry.config.ts

@@ -0,0 +1,19 @@
+import { defineConfig } from "vite";
+
+export default defineConfig({
+	build: {
+		emptyOutDir: false,
+		ssr: true,
+		target: "node18",
+		outDir: "build",
+		rollupOptions: {
+			input: {
+				telemetry: "src/telemetry.ts",
+			},
+		},
+		lib: {
+			formats: ["cjs"],
+			entry: "src/telemetry.ts",
+		},
+	},
+});