feat: add basic OTLP http metrics

Dockerfile

@@ -43,4 +43,4 @@ COPY . .
 RUN npm run build
 
 # Start the server using the production build
-CMD [ "node", "dist/main.js" ]
+CMD [ "node", "--require", "./otlp.js", "dist/main.js" ]

docker-compose-base.yaml

@@ -18,6 +18,12 @@ services:
       target: production
     environment:
       DATABASE_URI: mongodb://inventory-db:27017
+      OTEL_TRACES_EXPORTER: none
+      OTEL_EXPORTER_OTLP_ENDPOINT: "http://otel-collector:4318"
+      OTEL_NODE_RESOURCE_DETECTORS: env,host,os
+      OTEL_SERVICE_NAME: inventory
+      OTEL_SEMCONV_STABILITY_OPT_IN: http
+      NODE_OPTIONS: --require @opentelemetry/auto-instrumentations-node/register
     depends_on:
       - inventory-db
   inventory-db:

otlp.js

@@ -0,0 +1,23 @@
+const { NodeSDK } = require('@opentelemetry/sdk-node');
+const { OTLPMetricExporter } = require('@opentelemetry/exporter-metrics-otlp-http');
+const { PeriodicExportingMetricReader } = require('@opentelemetry/sdk-metrics');
+const { getNodeAutoInstrumentations } = require('@opentelemetry/auto-instrumentations-node');
+
+const sdk = new NodeSDK({
+  metricReader: new PeriodicExportingMetricReader({
+    exporter: new OTLPMetricExporter({ url: 'http://otel-collector:4318/v1/metrics' }),
+    exportIntervalMillis: 5000,
+  }),
+  instrumentations: [
+    getNodeAutoInstrumentations({
+      '@opentelemetry/instrumentation-http': {
+        'enabled': true,
+        'enhancedMetrics': true,
+        'tracing': false,
+      },
+    }),
+  ],
+});
+
+sdk.start();
+console.log('OpenTelemetry initialized ✅');