Activate request Transaction as current span

[Hugo-C]

Hi, I am looking to add some details on what's taking time in a request.
I looked at the documentation and examples provided by sentry:

• https://docs.sentry.io/platforms/rust/tracing/instrumentation/custom-instrumentation/#retrieve-a-transaction-or-span
• https://github.com/getsentry/sentry-rust/blob/master/sentry/examples/performance-demo.rs

But for some reasons it doesn't works with the transaction created in this crate. My attempt is here.

So I propose to expose the created transaction using a Rocket guard.

The result of performance_with_customs_spans:

get_current_transaction is what's really needed, SentryGuard and wrap_in_span are just for ease of use. We can also decide to keep get_current_transaction private and only expose SentryGuard ...

[Hugo-C]

@intgr let me know when you had some time to review it

[intgr]

I am terribly sorry, I have procrastinated about this PR.

But for some reasons it doesn't works with the transaction created in this crate. My attempt is here.

But my gut feeling is that we're not doing something right with Sentry APIs, and that's why it's not working using the approach documented by upstream.

The proposed solution seems more like a work-around. We should If doing it the "upstream way" doesn't work, we should understand it better, before implementing this approach.

I suspect what's going wrong right now is that we're creating a Transaction, but we're not telling Sentry "this is the current active transaction". But I haven't looked yet in detail.

[Hugo-C]

Thank you for your reply.
Actix seems indeed to work out of the box. I'll look into it.

[Hugo-C]

The trick was simply to use Scope.set_span, to "stack" the transactions (Sentry doc). For some reasons I believed it was done by Sentry automatically 😕.
Doing it the right way allow us to have captured messages linked:

I cleaned the PR to have only relevant commits. I also recycled the get_current_transaction, it looks better to me than the akward invalid_transaction.

[intgr]

Thanks! looks good to me.

Ooooops, this took over half a year. 😅

[intgr]

For a moment I thought that we could use scope.get_span() later to retrieve the transaction & avoid needing to clone/local_cache_once!()

But it's probably a bad idea, as the user might override the span. We should still finish the original one.

[intgr]

Released as v1.0.0 https://github.com/intgr/rocket-sentry/releases/tag/v1.0.0

[Hugo-C]

Wonderful!