sentry-tracing: `SentryLayer` ignores `event_filter` if `event_mapper` is set

[jinohkang-theori]

Environment

Linux x86_64

Steps to Reproduce

1. Build SentryLayer with both event_filter and event_mapper set.
   • event_filter ignores tracing events below Level::ERROR.
   • event_mapper always returns EventMapping::Event(..).
2. Emit a tracing event with Level::WARN (warn!()).

Expected Result

The warn event is discarded by the filter; the Sentry instance does not receive any events.

Actual Result

The warn event is not discarded by the filter; the Sentry instance receives the mapped event.

[Swatinem]

Yes, this is pretty much intentional. The event_mapper takes precedence over the filter, as you can also filter things in it, you just return an EventMapping::Ignore.

sentry-rust/sentry-tracing/src/layer.rs

Lines 136 to 138 in 3e7eec2

	let item = match &self.event_mapper {
	Some(mapper) => mapper(event, ctx),
	None => match (self.event_filter)(event.metadata()) {

Though I admit the docs might not fully reflect this.

[jinohkang-theori]

Yes, this is pretty much intentional. The event_mapper takes precedence over the filter, as you can also filter things in it, you just return an EventMapping::Ignore.

sentry-rust/sentry-tracing/src/layer.rs

Lines 136 to 138 in 3e7eec2

	let item = match &self.event_mapper {
	Some(mapper) => mapper(event, ctx),
	None => match (self.event_filter)(event.metadata()) {

Though I admit the docs might not fully reflect this.

Thank you for your swift response! I appreciate it, really.

I believe this behavior is part of stable API and guaranteed to stay the same in the foreseeable future. Is this correct? If this is the case, I could submit a PR to document this explicitly.

[Swatinem]

I believe this behavior is part of stable API and guaranteed to stay the same in the foreseeable future. Is this correct? If this is the case, I could submit a PR to document this explicitly.

Yes, we wouldn’t want to change this behavior suddenly. PRs to improve docs are always appreciated ❤️

[lcian]

Added this to the docs in #839