Add `otel.event.name` attribute reserved for OpenTelemetry

[pellared]

Area(s)

area:otel

What's missing?

Scenario 1: exporting event records for non-OTLP exporters

Non-OTLP exporters (e.g. a console/stdout exporter) need to emit EventName .

Scenario 2: emitting event records using logging libraries

Application developers that are already using some existing logging libraries (like log4j) may not want to additionally depend on OTel Logs API in places where they want to emit application-specific event records. Most logging libraries do not have a "event name" or "event ID" concept.

Describe the solution you'd like

Add otel.event_name attribute to the OTel attributes registry.

Scenario 1:
The non-OTLP exporters (like stdout exporter) can add otel.event_name attribute when exporting event records.

Scenario 2:
Users of non-OTel logging libraries can add otel.event_name attribute/field when emitting logs. Then the SDK or Collector can be configured with a log record processor that sets the EventName on log records that contain the otel.event_name attribute.
Prior art:

• sdk/log: Add EventNameProcessor example opentelemetry-go#7128

Other attribute keys that were considered:

• event.name - it is already deprecated. It is more probable to have collision with some attributes/fields that are already used by the end users. otel. prefix is already a convention for mapping with non-OTLP/OTel models
• otel.event_name - this was the original proposal, @trask gave feedback that having event. scopes it under "event" signal/domain

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[pellared]

@open-telemetry/specs-semconv-maintainers, I would appreciate it if we could reach an agreement on the attribute key (name) in the form of a comment on this issue, so that I can merge:

• sdk/log: Add EventNameProcessor example opentelemetry-go#7128

[lmolkova]

I assume otel. is proposed to stay consistent with other non-native things, but why not just event.name - we already have the attribute and it was used to capture exactly the same thing.

[pellared]

Other attribute keys that were considered:

• event.name - it is already deprecated. It is more probable to have collision with some attributes/fields that are already used by the end users. otel. prefix is already a convention for mapping with non-OTLP/OTel models

[lmolkova]

we can undeprecate it. If end-users set different EventName and event.name, they already have a problem, us adding otel.event.name would not really help them, would it?