tracing-dynamic

!Read this before using this library!

This is a small library to allow you to create dynamic attributes on spans.

Things to consider before using this:

It will leak memory. This happens on each instantiation of SpanFactory. You'll want to create span factories sparingly and reuse them.
I didn't test it in a real program.
It'll be slower than the tracing macros, but you came here for flexibility right?

If after reading the above you want to try it, here's how you can use it:

  let attrs = vec!["dyn_attr_1", "dyn_attr_2"];
  let span_factory = SpanFactory::new("span_name", "span_target", tracing::Level::INFO, None, None, None, &attrs);

  let subscriber = tracing_subscriber::fmt().pretty().finish();
  tracing::subscriber::with_default(subscriber, || {
      let span = span_factory.create();
      let _guard = span.enter();
      span.record("dyn_attr_1", &"dyn_attr_1");
      span.record("dyn_attr_2", &"dyn_attr_2");
      span.record("dyn_attr_4", &"dyn_attr_4"); // This attribute was not in the original metadata. It'll be ignored.
      tracing::error!("Hello world");
  });

Output

  2023-10-26T08:36:43.208049Z ERROR tracing_dynamic::span_factory::test: Hello world
    at src/span_factory.rs:60
    in span_target::span_name with dyn_attr_1: "dyn_attr_1", dyn_attr_2: "dyn_attr_2"

tracing_dynamic 0.1.0

tracing-dynamic