test: create a test app for OpenTelemetry work

packages/opentelemetry/lib/config/instrumentations.js

@@ -24,16 +24,41 @@ exports.createInstrumentationConfig = function createInstrumentationConfig() {
 	return [
 		getNodeAutoInstrumentations({
 			'@opentelemetry/instrumentation-http': {
+				startOutgoingSpanHook(request) {
+					return {
+						['net.host.name']: `set-by-instrumentation-http-start-outgoing-span-hook: ${request.path}`,
+						['peer.service']: 'test-peer-service',
+						['peer.name']: 'test-peer-name'
+					};
+				},
+				startIncomingSpanHook() {
+					return {
+						['net.host.name']:
+							'set-by-instrumentation-http-start-incoming-span-hook',
+						['peer.service']: 'test-peer-service',
+						['peer.name']: 'test-peer-name'
+					};
+				},
 				ignoreIncomingRequestHook
 			},
 			'@opentelemetry/instrumentation-fs': {
 				enabled: false
 			},
 			'@opentelemetry/instrumentation-pino': {
 				enabled: false
+			},
+			'@opentelemetry/instrumentation-undici': {
+				startSpanHook(request) {
+					return {
+						['server.address']: `set-by-instrumentation-undici-start-span-hook: ${request.path}`,
+						['peer.service']: 'test-peer-service',
+						['peer.name']: 'test-peer-name'
+					};
+				}
 			}
-		}),
-		new RuntimeNodeInstrumentation()
+		})
+		// Commented out to avoid a lot of spam when testing
+		// new RuntimeNodeInstrumentation()
 	];
 };
 

packages/opentelemetry/lib/config/metrics.js

@@ -32,11 +32,27 @@ exports.createMetricsConfig = function createMetricsConfig(options) {
 			headers['X-OTel-Key'] = options.apiGatewayKey;
 		}
 		config.metricReader = new PeriodicExportingMetricReader({
-			exporter: new OTLPMetricExporter({
-				url: options.endpoint,
-				compression: CompressionAlgorithm.GZIP,
-				headers
-			})
+			exportIntervalMillis: 5000,
+			exporter: {
+				// Test exporter to log metric names and attributes
+				export(metrics, done) {
+					metrics.scopeMetrics
+						.flatMap(({ metrics }) => metrics)
+						.map((metr) => ({
+							name: metr.descriptor.name,
+							attributes: metr.dataPoints.map((dp) => dp.attributes)
+						}))
+						.forEach((metric) => {
+							logger.info({
+								message: 'Exporting OpenTelementry metric',
+								metric
+							});
+						});
+					done({ code: 0 });
+				},
+				async forceFlush() {},
+				async shutdown() {}
+			}
 		});
 
 		logger.info({

packages/opentelemetry/lib/index.js

@@ -83,14 +83,15 @@ function setupOpenTelemetry({
 	};
 	instances.sdk.start();
 
-	// Set up host metrics if we have a metrics endpoint
-	if (metricsOptions?.endpoint) {
-		const meterProvider = /** @type {MeterProvider} */ (
-			opentelemetry.api.metrics.getMeterProvider()
-		);
-		instances.hostMetrics = new HostMetrics({ meterProvider });
-		instances.hostMetrics.start();
-	}
+	// Commented out to avoid a lot of spam when testing
+	// // Set up host metrics if we have a metrics endpoint
+	// if (metricsOptions?.endpoint) {
+	// 	const meterProvider = /** @type {MeterProvider} */ (
+	// 		opentelemetry.api.metrics.getMeterProvider()
+	// 	);
+	// 	instances.hostMetrics = new HostMetrics({ meterProvider });
+	// 	instances.hostMetrics.start();
+	// }
 
 	return instances;
 }

packages/opentelemetry/package.json

@@ -28,5 +28,10 @@
 		"@opentelemetry/instrumentation-runtime-node": "^0.7.0",
 		"@opentelemetry/sdk-node": "^0.53.0",
 		"@opentelemetry/semantic-conventions": "^1.26.0"
+	},
+	"devDependencies": {
+		"@types/express": "^4.17.21",
+		"express": "^4.21.0",
+		"node-fetch": "^2.6.7"
 	}
 }

packages/opentelemetry/test/end-to-end/fixtures/app.js

@@ -0,0 +1,31 @@
+const express = require('express');
+const nodeFetch = require('node-fetch');
+
+/**
+ * @returns {express.Application}
+ */
+exports.createTestApp = function createTestApp() {
+	const app = express();
+
+	app.get('/', async (request, response) => {
+		// Native fetch
+		const bulbasaur = await fetch(
+			'https://pokeapi.co/api/v2/pokemon/bulbasaur'
+		).then((response) => response.json());
+
+		// Node fetch
+		const squirtle = await nodeFetch(
+			'https://pokeapi.co/api/v2/pokemon/squirtle'
+		).then((response) => response.json());
+
+		response.send(
+			[
+				`Bulbasaur has the types: ${bulbasaur.types.map(({ type }) => type.name).join(', ')}`,
+				`Squirtle has the types: ${squirtle.types.map(({ type }) => type.name).join(', ')}`,
+				''
+			].join('\n')
+		);
+	});
+
+	return app;
+};

packages/opentelemetry/test/end-to-end/scripts/run-test-app.js

@@ -0,0 +1,12 @@
+const { createTestApp } = require('../fixtures/app');
+const logger = require('@dotcom-reliability-kit/logger');
+
+const app = createTestApp();
+
+const server = app.listen(4001, () => {
+	logger.info('Test app running on port 4001');
+});
+
+process.on('beforeExit', () => {
+	server.close();
+});

packages/opentelemetry/test/end-to-end/scripts/run.js

@@ -0,0 +1,22 @@
+const { fork } = require('node:child_process');
+const { join: joinPath } = require('node:path');
+
+const cwd = __dirname;
+const env = {
+	HEROKU_RELEASE_CREATED_AT: 'mock-release-date',
+	HEROKU_SLUG_COMMIT: 'mock-commit-hash',
+	LOG_LEVEL: 'debug',
+	OPENTELEMETRY_METRICS_ENDPOINT: 'http://localhost:4318/v1/metrics',
+	REGION: 'mock-region',
+	SYSTEM_CODE: 'reliability-kit/opentelemetry'
+};
+
+const app = fork(joinPath(cwd, 'run-test-app.js'), {
+	cwd,
+	env,
+	execArgv: ['--require', '@dotcom-reliability-kit/opentelemetry/setup']
+});
+
+app.on('close', (code) => {
+	process.exit(code);
+});