Refactor rekor-monitor workflow

[linus-sun]

Summary

As per the following doc, this PR refactors rekor-monitor to make running the identity monitor easier to configure through an updated input configuration, as well as adding better error handling and logic for determining what indices to run the identity monitor on in the case that the user does not input a given start or end index for the identity monitor portion of the reusable monitoring workflow.

Release Note

The identity monitor input configuration has been updated.

Documentation

The README has been updated accordingly with proper run instructions for the reusable monitoring workflow.

[codecov]

Codecov Report

Attention: Patch coverage is 2.32558% with 126 lines in your changes missing coverage. Please review.

Project coverage is 62.46%. Comparing base (d271ec7) to head (2ea93b0).
Report is 164 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/rekor_monitor/main.go	0.00%	124 Missing ⚠️
pkg/rekor/identity.go	66.66%	1 Missing ⚠️
pkg/rekor/verifier.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #526      +/-   ##
==========================================
- Coverage   64.02%   62.46%   -1.57%     
==========================================
  Files           4       17      +13     
  Lines         303     1276     +973     
==========================================
+ Hits          194      797     +603     
- Misses         78      408     +330     
- Partials       31       71      +40     

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

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[mihaimaruseac]

Looks good, I only have a set of minor comments / nits.

[haydentherapper]

We chatted offline, but I've realized that this is going to introduce a lot of duplication, especially as we add more ways to monitor the log (CT consistency, CT monitoring, tile monitoring, etc). To avoid duplication, I'd suggest we:

• Keep only one GitHub Actions workflow, reusable_monitoring.yml seems like a generic enough name.
• Keep consistency checks and monitoring under the same executable, but have a different executable for each monitored log (e.g cmd/rekor_monitor/main.go, cmd/ct_monitor/main.go)
• Keep reading the latest index from a checkpoint rather than the IdentityMetadata output. I think that file is still useful to later expand to include skipped entries though, so no need to revert any changes there.

Sorry for the pivot backwards, but hopefully this will keep the code easier to maintain.

[haydentherapper]

Looks great!

[haydentherapper]

Looks great!