Refactor ReactorUtils into its own sentry-reactor module

[lcian]

📜 Description

Refactor ReactorUtils into its own sentry-reactor module

💡 Motivation and Context

Part of #3144

💚 How did you test it?

Unit tests and manual tests with the webflux samples.

📝 Checklist

• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

Pending actions:

• merge release registry PR
• release
• .craft.yml
• merge docs PR
• add main README entry

Comments

• Do we need to add this module to the Gradle and Maven plugins?
  No, it will still be included in the Spring and Spring Boot integrations, just as a different module.
• Any extra steps required for release of the SDK and/or the plugins?
  We need to add an entry to the sentry-release-registry and then update .craft.yml (post-release)
• Do we need a major for this? Should we keep the old classes and mark them as deprecated instead, so that we can remove the old ones and swap to these on the next major?
  We will add a deprecation warning and make the old classes extend the new ones, so we don't break existing customers.
• Update the docs if needed

[lcian]

The commented out tests in SentryReactorUtilsTest are currently failing and I don't understand why.
The setup we do in the setup function should be sufficient to enable context propagation and use our SentryReactorThreadLocalAccessor.

Edit: I was not initializing the SDK :) Also the ThreadLocalAccessor can be set up with SPI instead.

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	427.45 ms	449.10 ms	21.65 ms
Size	1.58 MiB	2.21 MiB	641.11 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
c2c78de	415.28 ms	505.08 ms	89.80 ms

App size

Revision	Plain	With Sentry	Diff
c2c78de	1.58 MiB	2.21 MiB	640.27 KiB

Previous results on branch: lcian/ref/reactor-as-module

Startup times

Revision	Plain	With Sentry	Diff
7276711	444.02 ms	475.80 ms	31.78 ms
67c204c	397.52 ms	481.22 ms	83.70 ms
c320936	369.81 ms	481.23 ms	111.42 ms
74b0da5	380.19 ms	454.58 ms	74.40 ms
4bbe412	423.04 ms	466.40 ms	43.36 ms
10216d9	482.39 ms	514.26 ms	31.87 ms
3dd4220	373.60 ms	468.00 ms	94.40 ms

App size

Revision	Plain	With Sentry	Diff
7276711	1.58 MiB	2.21 MiB	640.27 KiB
67c204c	1.58 MiB	2.21 MiB	640.25 KiB
c320936	1.58 MiB	2.21 MiB	640.27 KiB
74b0da5	1.58 MiB	2.21 MiB	640.27 KiB
4bbe412	1.58 MiB	2.21 MiB	640.27 KiB
10216d9	1.58 MiB	2.21 MiB	640.25 KiB
3dd4220	1.58 MiB	2.21 MiB	640.27 KiB

[adinauer]

Not fully done with reviewing the PR, so I'm just sending the comments I have already.
Also I opened a PR to fix some things: #4160

[adinauer]

Other things that might be missing from this PR:

• .craft.yml (we can only do this once the sentry-release-registry entry exists and we released this once)
• bug_report_java.yml should allow selecting the module for bug reports
• a README in the new module would be great
• root README has a list of modules where we should add this
  • there's also some missing there, we should add those as well, e.g. sentry-opentelemetry-agentless and sentry-opentelemetry-agent-spring

We need manually add this new module to sentry-release-registry after releasing this new module but we can already prepare the PR there beforehand.

Docs would also be great.

[adinauer]

LGTM!

We shouldn't forget to update release registry, then update .craft.yml here.
Also would be great to have an entry in the root README listing this new module.

[lcian]

Thanks @adinauer . I'll add this to the README after it's released, otherwise we'll have broken links. I'll add this to the issue for v8.3.0 so we don't forget about the missing tasks.