chore(config): remove config field from Reloader

[Molter73]

Description

This field is only really used at startup and then simply becomes a thing to be kept in memory with no additional value, the internal watch channels Reloader uses already has owned copies of everything in there.

Checklist

• Patch has a change log entry OR does not need one.
• Investigated and inspected CI test results
• Updated documentation accordingly

Automated testing

• Added unit tests
• Added integration tests
• Added regression tests

If any of these don't apply, please comment below.

Testing Performed

Added unit tests to config::reloader::Reloader.

The tests themselves are pretty basic, they simply:

• Create a FactConfig object.
• Turn it into a Reloader.
• Feed a new FactConfig object to the Reloader.
• Check the correspoding watch::Receiver to see the expected update.

These tests show some inconsistencies on how updating from or to
explicit versions of default values behave, some fields send an update
and some don't. We might want to address this at some point.

A new approach is also used for the added tests, instead of using an
array for defining the cases and iterating over them, the main logic is
abstracted in a macro and invoked for each set of input/expected values.
This gives a few benefits:

• Each test case gets a dedicated test name, making it easier to find
  where an error occurs.
• If one test case fails, the rest still run (the array iteration
  approach stops at the first failure).
• All test cases are run in parallel, potentially speeding up the tests
  (though the current state of tests is fast enough for now).

The downside is the number of tests bloats quite a bit, but this should
not be too much of an issue.

This new approach is properly described here: https://unterwaditzer.net/2023/rust-test-parametrization.html

Summary by CodeRabbit

• Bug Fixes

  • Improved configuration reload handling across paths, scan intervals, rate limits, endpoints, gRPC, and OpenTelemetry settings.
  • Configuration changes now propagate more reliably without unnecessary updates.
  • Hot-reload enablement remains consistent after configuration changes.

• Refactor

  • Streamlined internal pipeline setup while preserving existing runtime behavior.

• Tests

  • Added comprehensive coverage for configuration updates, defaults, changes, and no-op reloads.

[coderabbitai]

📝 Walkthrough

Walkthrough

The reloader now stores startup hotreload state and propagates field-specific configuration updates through watch channels. Pipeline setup passes BPF and runtime state through SetupArgs, and tests cover reload behavior across configuration fields.

Changes

Reloader and pipeline refactor

Layer / File(s)	Summary
Reloader state and update propagation fact/src/config/reloader/mod.rs, fact/src/config/reloader/tests.rs	Reloader stores startup hotreload enablement, propagates configuration changes through send_updates, and adds generated tests for paths, timing, endpoint, gRPC, and OTel fields.
Explicit pipeline setup arguments fact/src/lib.rs, fact/src/bpf/mod.rs	Pipeline setup bundles runtime handles and cloned BPF configuration in SetupArgs; BPF tests and initialization no longer access BPF configuration through the reloader.

Estimated code review effort: 4 (Complex) | ~45 minutes

Possibly related PRs

• stackrox/fact#1010: Adds replay-mode wiring in the same fact/src/lib.rs orchestration flow.
• stackrox/fact#1086: Adds configurable BPF program loading supported by explicit BPF configuration passing.

Suggested reviewers:stringy

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the main change: removing the stored config field from Reloader.
Description check	✅ Passed	The PR description follows the template and includes a clear summary, checklist, automated testing, and testing notes.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch mauro/chore/remove-config-from-reloader

---

_{Comment @coderabbitai help to get the list of available commands.}

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.00000% with 44 lines in your changes missing coverage. Please review.
✅ Project coverage is 35.97%. Comparing base (922750c) to head (1f2081d).

Files with missing lines	Patch %	Lines
fact/src/lib.rs	0.00%	32 Missing ⚠️
fact/src/config/reloader/mod.rs	78.57%	12 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #1293 +/- ##
==========================================
+ Coverage 32.73% 35.97% +3.24% 
==========================================
Files 22 22 Lines 3174 3180 +6 Branches 3174 3180 +6 ==========================================
+ Hits 1039 1144 +105 + Misses 2131 2033 -98 + Partials 4 3 -1 

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.