Add OTel (#114)

* init otel

* deflock group

* no internal metrics

* only log errors for now

api/telemetry.ts

@@ -0,0 +1,49 @@
+import { NodeTracerProvider, BatchSpanProcessor } from '@opentelemetry/sdk-trace-node';
+import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-http';
+import { LoggerProvider, BatchLogRecordProcessor } from '@opentelemetry/sdk-logs';
+import { OTLPLogExporter } from '@opentelemetry/exporter-logs-otlp-http';
+import { MeterProvider, PeriodicExportingMetricReader } from '@opentelemetry/sdk-metrics';
+import { OTLPMetricExporter } from '@opentelemetry/exporter-metrics-otlp-http';
+import { resourceFromAttributes } from '@opentelemetry/resources';
+import { trace, metrics } from '@opentelemetry/api';
+import { logs, SeverityNumber } from '@opentelemetry/api-logs';
+
+export { SeverityNumber };
+
+const OTEL_ENDPOINT = process.env.OTEL_EXPORTER_OTLP_ENDPOINT ?? 'http://127.0.0.1:4318';
+
+const resource = resourceFromAttributes({
+  'service.name': 'deflock-api',
+  'deployment.environment': process.env.NODE_ENV ?? 'production',
+});
+
+const tracerProvider = new NodeTracerProvider({
+  resource,
+  spanProcessors: [
+    new BatchSpanProcessor(new OTLPTraceExporter({ url: `${OTEL_ENDPOINT}/v1/traces` })),
+  ],
+});
+tracerProvider.register();
+
+const loggerProvider = new LoggerProvider({
+  resource,
+  processors: [
+    new BatchLogRecordProcessor(new OTLPLogExporter({ url: `${OTEL_ENDPOINT}/v1/logs` })),
+  ],
+});
+logs.setGlobalLoggerProvider(loggerProvider);
+
+const meterProvider = new MeterProvider({
+  resource,
+  readers: [
+    new PeriodicExportingMetricReader({
+      exporter: new OTLPMetricExporter({ url: `${OTEL_ENDPOINT}/v1/metrics` }),
+      exportIntervalMillis: 10_000,
+    }),
+  ],
+});
+metrics.setGlobalMeterProvider(meterProvider);
+
+export const tracer = trace.getTracer('deflock-api', '1.0.0');
+export const otelLogger = logs.getLogger('deflock-api', '1.0.0');
+export const meter = metrics.getMeter('deflock-api', '1.0.0');