⚡️ Temporarily enable OTel diagnostics (#60902)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: heiskr

src/observability/lib/tracing.ts

@@ -26,12 +26,14 @@ import { ExpressInstrumentation } from '@opentelemetry/instrumentation-express'
 import { HttpInstrumentation } from '@opentelemetry/instrumentation-http'
 import { UndiciInstrumentation } from '@opentelemetry/instrumentation-undici'
 import { NodeSDK } from '@opentelemetry/sdk-node'
+import { diag, DiagConsoleLogger, DiagLogLevel } from '@opentelemetry/api'
 
-// For tracing diagnostics, uncomment these lines:
-// import { diag, DiagConsoleLogger, DiagLogLevel } from '@opentelemetry/api'
-// diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.DEBUG)
-
+// TEMPORARY: enable OTel diagnostic logging to investigate why traces aren't
+// arriving in the collector. See github/docs-engineering#6046. Revert once
+// the export pipeline is confirmed working.
 if (process.env.OTEL_EXPORTER_OTLP_TRACES_ENDPOINT) {
+  diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.INFO)
+
   const sdk = new NodeSDK({
     serviceName: process.env.OTEL_SERVICE_NAME || 'docs-internal',
     traceExporter: new OTLPTraceExporter({}),