Fix traceId discrepancy in case error in servlet web

[nkonev]

Fixes #12610

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As I see from my research, the bug happens only in the real servlet environment, supposedly because of HttpServletResponse.sendError(), I didn't manage to reproduce it via mockMvc.
Tomcat creates a new HttpServletRequest in case error, which is related to "/error" path, which will be served by ErrorController.
Fortunately, request attributes are copied from the original request to the "/error"-related one, so we can put the ObservationView into the original request in order to extract this ObservationView from "/error"-related request and create a new parent observation with a given parent ObservationView. The last ObservationView propagates TraceContext to the new Observation so we have the same traceId.

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Reproducer is here https://github.com/nkonev/trace-discrepancy-reproducer

curl -i 'http://localhost:8060/internal/profile/auth' -X GET -H 'Accept: text/plain, */*'

To check that the bug is fixed, you can run publishMavenJavaPublicationToMavenLocal in spring-security:web

./gradlew :spring-security-web:publishMavenJavaPublicationToMavenLocal --offline

or via IDE

then switch to the SNAPSHOT dependency nkonev/trace-discrepancy-reproducer@131a271

Before:

After:

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UPD:
I also checked this PR with jetty and undertow, it works fine.

[nkonev]

PTAL @jzheaux

[nkonev]

@jzheaux
When you have a chance, I’d appreciate your review or thoughts.

[nkonev]

@marcusdacoregio @jzheaux
please take a look when you have a time

[jzheaux]

Thanks for the PR and the sample application, @nkonev. I've left some feedback inline.

Also, I think we should try adding a test for it. That may mean dispatching to ERROR manually in the test.

[jzheaux]

Given that the parent observations are available through the AroundFilterObservation instance, it seems like the ATTRIBUTE attribute should be sufficient.

For example, instead of two other attributes, would this give you what you need:

AroundFilterObservation parent = (AroundFilterObservation) request.getAttribute(ATTRIBUTE);
if (parent != null) {
    beforeContext.setParentObservation(parent.before().getContext().getParentObservation());
    afterContext.setParentObservation(parent.after().getContext().getParentObservation());
}

Note that I tried this modification locally and the traceId is preserved in your project.

[nkonev]

Thank you for review @jzheaux !

That may mean dispatching to ERROR manually in the test.

Can you please explain it a bit more ? I still don't understand for what I need to write an assertion ?

May be somewhere there is a similar test which I can copy and modify for this particular issue ?

Did you mean to use MockMvc ?

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In the time when I wrote this PR I considered to make the following test:
Create request 1
then somehow fail it
then manually copy attributes to the request 2 (/error-related) -- to simulate servlet container
then assert the tracing contexts has the similar traceId

I decided it is too artificial in that time.

Do you mean to something like this ?