Observability - 可観測性とトレーシング

// svelte.config.js
/** @type {import('@sveltejs/kit').Config} */
const config = {
	kit: {
		experimental: {
			tracing: {
				server: true,
			},
			instrumentation: {
				server: true,
			},
		},
	},
};

export default config;

npm install @opentelemetry/sdk-node \
  @opentelemetry/auto-instrumentations-node \
  @opentelemetry/exporter-trace-otlp-proto \
  import-in-the-middle

// src/instrumentation.server.ts
import { NodeSDK } from '@opentelemetry/sdk-node';
import { getNodeAutoInstrumentations } from '@opentelemetry/auto-instrumentations-node';
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-proto';
import { createAddHookMessageChannel } from 'import-in-the-middle';
import { register } from 'node:module';

// import-in-the-middle の設定
const { registerOptions } = createAddHookMessageChannel();
register('import-in-the-middle/hook.mjs', import.meta.url, registerOptions);

// OpenTelemetry SDK の設定
const sdk = new NodeSDK({
	serviceName: 'my-sveltekit-app',
	traceExporter: new OTLPTraceExporter(),
	instrumentations: [getNodeAutoInstrumentations()],
});

sdk.start();

console.log('OpenTelemetry tracing started');

# Docker を使用した Jaeger の起動
docker run -d --name jaeger \
  -e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \
  -e COLLECTOR_OTLP_ENABLED=true \
  -p 16686:16686 \
  -p 4317:4317 \
  -p 4318:4318 \
  jaegertracing/all-in-one:latest

# .env
OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
OTEL_SERVICE_NAME=my-sveltekit-app

// src/lib/server/auth.ts
import { getRequestEvent } from '$app/server';

export async function authenticate() {
	const event = getRequestEvent();

	// root スパン: handle フックに関連付けられたスパン
	// current スパン: 現在の load, action, または remote function のスパン

	// ユーザー情報を root スパンに追加
	const user = await getAuthenticatedUser();
	event.tracing.root.setAttribute('userId', user.id);
	event.tracing.root.setAttribute('userRole', user.role);

	return user;
}

// src/routes/api/products/+server.ts
import type { RequestHandler } from './$types';
import { getRequestEvent } from '$app/server';

export const GET: RequestHandler = async ({ url }) => {
	const event = getRequestEvent();

	// クエリパラメータを記録
	const category = url.searchParams.get('category');
	event.tracing.current.setAttribute('product.category', category || 'all');

	// パフォーマンスメトリクスを記録
	const startTime = performance.now();

	const products = await fetchProducts(category);

	const duration = performance.now() - startTime;
	event.tracing.current.setAttribute('db.query.duration', duration);
	event.tracing.current.setAttribute('product.count', products.length);

	return json(products);
};

// src/routes/dashboard/+page.server.ts
import type { PageServerLoad } from './$types';
import { getRequestEvent } from '$app/server';

export const load: PageServerLoad = async ({ locals }) => {
	const event = getRequestEvent();

	// データ取得の開始を記録
	event.tracing.current.setAttribute('dashboard.loading', true);

	const [stats, activities, notifications] = await Promise.all([
		fetchStats(locals.userId),
		fetchActivities(locals.userId),
		fetchNotifications(locals.userId),
	]);

	// 結果のサマリーを記録
	event.tracing.current.setAttribute('dashboard.stats.count', stats.length);
	event.tracing.current.setAttribute('dashboard.activities.count', activities.length);
	event.tracing.current.setAttribute('dashboard.loading', false);

	return { stats, activities, notifications };
};

npm install @vercel/otel

// src/instrumentation.server.ts
import { initOpenTelemetry } from '@vercel/otel';

initOpenTelemetry({
	serviceName: 'my-sveltekit-app',
});

// src/instrumentation.server.ts
import { NodeSDK } from '@opentelemetry/sdk-node';
import { DatadogExporter } from '@opentelemetry/exporter-datadog';

const sdk = new NodeSDK({
	serviceName: process.env.DD_SERVICE || 'my-sveltekit-app',
	traceExporter: new DatadogExporter({
		apiKey: process.env.DD_API_KEY,
	}),
});

sdk.start();

// src/instrumentation.server.ts
import { NodeSDK } from '@opentelemetry/sdk-node';
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-proto';

const sdk = new NodeSDK({
	serviceName: 'my-sveltekit-app',
	traceExporter: new OTLPTraceExporter({
		url: 'https://otlp.nr-data.net:4318/v1/traces',
		headers: {
			'api-key': process.env.NEW_RELIC_LICENSE_KEY,
		},
	}),
});

sdk.start();

// src/instrumentation.server.ts
import { NodeSDK } from '@opentelemetry/sdk-node';
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-proto';
import { dev } from '$app/environment';

// 開発環境またはプレビュー環境でのみ有効化
if (dev || process.env.ENABLE_TRACING === 'true') {
	const sdk = new NodeSDK({
		serviceName: 'my-sveltekit-app',
		traceExporter: new OTLPTraceExporter(),
	});

	sdk.start();
}

import { NodeSDK } from '@opentelemetry/sdk-node';
import { TraceIdRatioBasedSampler } from '@opentelemetry/sdk-trace-base';

const sdk = new NodeSDK({
	serviceName: 'my-sveltekit-app',
	// 10% のリクエストのみトレース
	sampler: new TraceIdRatioBasedSampler(0.1),
});

// src/routes/api/orders/+server.ts
import type { RequestHandler } from './$types';
import { getRequestEvent } from '$app/server';
import { error } from '@sveltejs/kit';

export const POST: RequestHandler = async ({ request }) => {
	const event = getRequestEvent();

	try {
		const data = await request.json();

		// 処理開始を記録
		event.tracing.current.setAttribute('order.processing', true);

		const order = await createOrder(data);

		// 成功を記録
		event.tracing.current.setAttribute('order.id', order.id);
		event.tracing.current.setAttribute('order.status', 'created');

		return json(order);
	} catch (err) {
		// エラーをスパンに記録
		event.tracing.current.setAttribute('error', true);
		event.tracing.current.setAttribute('error.message', err.message);
		event.tracing.current.setAttribute('error.type', err.name);

		throw error(500, 'Order creation failed');
	}
};

Error: Cannot find module '@opentelemetry/api'

npm install @opentelemetry/api