Pino: Allow logging trace metadata under different keys

[drewcorlin1]

Is your feature request related to a problem? Please describe

The current pino instrumentation from @opentelemetry/instrumentation-pino injects 3 fields into each log, trace_id, span_id and trace_flags. These fields are useful, but the snake case naming is slightly problematic in my case, where my company has strict logging standards and we'd like to use camelCase.

Describe the solution you'd like to see

Allowing a different set of keys to be used in the config (this is assuming you are configuring the instrumentation via getNodeAutoInstrumentations from @opentelemetry/auto-instrumentations-node).

'@opentelemetry/instrumentation-pino': {
  camelCase: true
}

Describe alternatives you've considered

Reformatting the log manually, via the logHook config.

'@opentelemetry/instrumentation-pino': {
    logHook: (span, record) => {
      // Reformat the injected log fields to use camelCase, eg. trace_id -> traceId
      const context = span.spanContext();
      record.traceId = context.traceId;
      record.spanId = context.spanId;
      record.traceFlags = context.traceFlags;

      // Be extra safe, in case someone manually logged these fields, even though they shouldn't
      if (record.trace_id === context.traceId) delete record.trace_id;
      if (record.span_id === context.spanId) delete record.span_id;
      if (record.trace_flags === context.traceFlags) delete record.trace_flags;
    },
  },

Additional context

[Flarna]

I think it would be more flexible to allow to override the actual key names instead of adding just one more fixed set. e.g

'@opentelemetry/instrumentation-pino': {
  traceIdKey: 'traceId', // default is 'trace_id
  spanIdKey: 'span.id', // default is 'span_id'
  trace_flags: 'my-trace-flags'  // defaults to 'trace_flags'
}

And well, it would be nice to have the same/similar config for other log instrumentations like winston,...

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[drewcorlin1]

Not stale

[mbrevda]

This could also be useful for specific log destinations. For example. GCP requires the following format:

   const trace = `projects/${projectId}/traces/${traceId}`;
      res['logging.googleapis.com/trace'] = trace;
    }
    res['logging.googleapis.com/trace_sampled'] = traceFlags;
    res['logging.googleapis.com/spanId'] = spanId;

[trentm]

@drewcorlin1 This can be closed now, right (it was handled by #1867)?

[drewcorlin1]

@drewcorlin1 This can be closed now, right (it was handled by #1867)?

Yes!