[WIP] opentelemetry-aware event formatter

[hawkw]

this doesn't quite work yet, but i thought it could be nice to have --- possibly @jtescher has some advice on how to handle remote parents nicely (and, if i'm missing anything that we should be logging?)

[jtescher]

Exciting! Couple of quick ideas for getting things closer to what you may have wanted

[jtescher]

This logic is a little complex currently unfortunately. Basically 3 cases here:

1. parent context with active span
2. parent context with remote span
3. set trace id in builder

So you should see the correct trace ids with something along the lines of:

span.as_ref()
    .and_then(|span| {
        let ext = span.extensions();
        let builder = ext.get::<otel::SpanBuilder>()?;

        if let Some(ref parent) = builder.parent_context {
            if parent.has_active_span() {
                return Some(parent.span().span_context().trace_id());
            }
            if let Some(remote) = parent.remote_span_context() {
                return Some(remote.trace_id());
            }
        }

        builder.trace_id
    })
    .unwrap_or_else(otel::TraceId::invalid)

[hawkw]

thanks! i was having a really hard time figuring out what the right logic here was, that's really helpful.

[jtescher]

remote_parent.trace_flags() may actually be more interesting here as it contains sampling information and is present in all spans, values from the tracestate-header are less common and often opaque to the application anyway

[hawkw]

okay, thanks! i wasn't sure which data was more likely to be useful — perhaps we would want an option to show trace flags for local spans as well, for debugging sampling?

i was hoping there was a way to get key-value data, names, etc for remote spans to display in the logs, but it seems like that's not available to us...(which does make sense; we wouldn't want to pass that data around everywhere). is there any way we can hydrate that data from span IDs, or is that not supported?

[jtescher]

okay, thanks! i wasn't sure which data was more likely to be useful — perhaps we would want an option to show trace flags for local spans as well, for debugging sampling?

Yeah I think that would make sense as an option 👍

i was hoping there was a way to get key-value data, names, etc for remote spans to display in the logs, but it seems like that's not available to us...(which does make sense; we wouldn't want to pass that data around everywhere). is there any way we can hydrate that data from span IDs, or is that not supported?

That would be interesting but I don't think that it's possible to get information about remote spans currently, you basically just work with a serialized SpanContext when injecting/extracting.

[bryangarza]

This seems useful, would love to see it get merged in the future.