No root span on some traces using Opentelemetry

[bradleyberwick]

Summary

I'm using Opentelemetry to send traces and metrics from my Next.js app to Grafana. For all API requests and *.json requests, the traces do no have a root span i.e. there's no span with 'parentSpanID = 0000000000000000'. This is an issue as I can't view the traces correctly in Grafana. My Opentelemetry instrumentation code is below.

Is there an issue with my instrumentation or is this an issue with Next.js?

I'm pretty new to Next.js so if there's any other helpful information which I've not included here, please let me know.

Additional information

const { NodeSDK } = require('@opentelemetry/sdk-node');
const { PeriodicExportingMetricReader, ConsoleMetricExporter } = require('@opentelemetry/sdk-metrics');
const { OTLPTraceExporter } = require('@opentelemetry/exporter-trace-otlp-grpc');
const { OTLPMetricExporter } = require('@opentelemetry/exporter-metrics-otlp-grpc');
const { getNodeAutoInstrumentations } = require('@opentelemetry/auto-instrumentations-node');

const sdk = new NodeSDK({
// Autoinstrumentation (run in App Service) - tested this and like the OTEL frontend app, it doesn't provide correct request names in traces and there's also no http.route label for http metrics
  traceExporter: new OTLPTraceExporter(), // new ConsoleSpanExporter()
  metricReader: new PeriodicExportingMetricReader({
    exporter: new OTLPMetricExporter(), // new ConsoleMetricExporter()
  }),
  instrumentations: [
    getNodeAutoInstrumentations({
      '@opentelemetry/instrumentation-fs': {
        enabled: false,
      },
      '@opentelemetry/instrumentation-http': {
          // This gives your request spans a more meaningful name than `HTTP GET`
          requestHook: (span, request) => {
            span.updateName( `${request.method} ${request.url || request.path}` );
            // The below is only working on spans with kind=client, not kind=server
            span.setAttribute('http.route', request.path);
          },
       }
    })
  ]
});

sdk.start();

Example

No response

[StephenGoodall]

@bradleyberwick did you manage to find a workaround for this issue? I think I'm coming across the same one, I get lots of spans, and they do show up as being connected to each other - but none of them are marked as root spans, which makes it hard to make sense of them.

I've tried with the vercel/otel option and the opentelemetry version (like your example) and I think it behaves the same either way.

PS. If you don't mind, I might have to borrow that requestHook! 😃