OTEL span event name format

[erka]

This is no clear example in the specification of how span events should be named. I expected that the demo to provide some guidance on this topic, but unfortunately it doesn't follow the unified style for event name. Each service seems to use its own approach. For example,

• Error in Ad service
• Currencies fetched, response sent back, Conversion failed, Processing currency conversion request,... in Currency service
• error, shipped, prepared, ... in Checkout service
• Product Not Found: %s, Product Found, ... in Product Catalog service
• Fetch cart, Empty cart in Cart service if they are span events.

What is the correct format for an event name?

[julianocosta89]

Great discussion @erka!
I think it is pretty clear that we have never thought about span events on the demo.
This definitely needs some improvement.

I want to bring this reference to the discussion: https://opentelemetry.io/docs/concepts/signals/traces/#span-events

If the timestamp in which the operation completes is meaningful or relevant, attach the data to a span event.

We also have this blog post from @austinlparker: https://opentelemetry.io/blog/2025/opentelemetry-logging-and-you/

But other than those pages, I don't think we have anything that the community agree on related to span events best practices.

TBH I'm not sure if we should invest on span events, as they will eventually be deprecated:
https://github.com/open-telemetry/opentelemetry-specification/blob/main/oteps/4430-span-event-api-deprecation-plan.md

But we could do it, and then migrate to (log-based) events whenever they are usable.

@jpkrohling has been publishing a series of recommendations on the OTel blog.
Juraci, do you have anything on Span Events planned?

[erka]

@julianocosta89 Thank you for extra information.

The LogRecord also has an EventName property, and I think it would follow the guidance in the same way as a span event name.
https://github.com/open-telemetry/opentelemetry-specification/blob/v1.49.0/specification/logs/data-model.md#field-eventname

I’d greatly appreciate any advice on how to name it.