Best Practice Usage of Trace ID

[ethangodt]

• This only affects the JavaScript OpenTelemetry library
• This may affect other libraries, but I would like to get opinions here first

Hello 👋

I'm working on a JS lib for my team and seeking advice about the best way to handle trace ids. I'm new to Open Telemetry, and my understanding at this point is that trace ids are used to correlate disparate events for enhanced visibility and discoverability.

For proof of concept work, I am currently testing with this vendor library which makes use of some default @open-telemetry instrumentations.

When I integrate this code into my page I'm correctly sending traces, but I'm noticing that there is a different trace id for each instrumentation. On one hand, it makes sense that fetch/ajax tracking have their own trace id (each request is traceable uniquely through a backend system), but in the case of other events (like all core web vitals, user click events, etc.) it seems desirable to correlate these with the same trace id.

Why do the libraries in this repo default to using a unique trace id in most cases? How should I think about this concept? Am I suppose to be supplying a trace id to these instrumentations at page load? Is there meaningful definition somewhere between a trace id and a session id?

Example:

[AbhiPrasad]

@ethangodt you may want to check out https://docs.google.com/document/d/13Z9CD-JlT_HQwx1qJnkkZnGSLe6qb67qHxQ3tu_pevM/edit#.

Concepts of traces/sessions in the browser is still being figured out by the OpenTelemetry team. This is being actively discussed by the Client Instrumentation SIG. You can reach out to them on slack.

[scheler]

but in the case of other events (like all core web vitals, user click events, etc.) it seems desirable to correlate these with the same trace id.

these events could happen over a very long time period, you do want to model them as spans in a single trace. With Sessions, all the spans and events from multiple pages will get associated to a common session, but if I understand your requirement correctly, what you want is a way to associate web vitals and user interaction events to the page that emitted these events. This is a common concern outside of individual instrumentations, hence it is not present in any instrumentation. You could implement this yourself by implementing a "LogRecord Processor" that adds location.href as an attribute to these events. Adding the traceId/spanId of the documentLoad span of the page could be a bit complex but it is along these lines that you can think.