A bit confused about tracing-log v0.2.0

[frederikhors]

I'm a bit confused about tracing-log v0.2.0.

I was using

tracing = { version = "0.1.40", default-features = false, features = ["log"] }
tracing-appender = { version = "0.2.2", default-features = false }
tracing-log = { version = "0.1.3", default-features = false }
tracing-subscriber = { version = "0.3.17", default-features = false }

like this:

use tracing_log::LogTracer;

//...

LogTracer::init().expect("tracer init");

//...

What should I do now with v0.2.0?

[davidbarsky]

You can remove LogTracer entirely and only use the tracing crate's log feature: https://github.com/tokio-rs/tracing/releases/tag/tracing-log-0.2.0.

[hawkw]

I don't think @davidbarsky's answer is correct. The API that was removed in tracing-log v0.2.0 was TraceLogger (which had been deprecated for a while), not LogTracer, which should still be present: https://docs.rs/tracing-log/latest/tracing_log/struct.LogTracer.html.

The issue here is that LogTracer API is feature flagged. Since you're depending on tracing-log with default-features = false, you need to add features = ["log-tracer"] for the API to be present. The reason that it worked with tracing-log v0.1.x is that some other crate in your dependency tree also depends on tracing-log v0.1 with that feature flag enabled, so it was enabled for you by that dependency.

[frederikhors]

@hawkw Thanks. Anyway if I remove LogTracer::init().expect("tracer init"); and tracing-log crate everything works like before.

Is this correct?

[hawkw]

Are you actually using log logs in your program? tracing-log is only necessary if you want to consume logs emitted using the log crate as part of your tracing diagnostics.

[frederikhors]

Yep. I'm using tracing::info!() along with tracing_subscriber. And it works!