Development: Defer eager bean initialization and refactor services to reduce server startup time

[tobias-lippert]

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.
• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

Server

• I strictly followed the server coding and design guidelines.
• I documented the Java code using JavaDoc style.

Motivation and Context

Server startup is quite slow. Locally it takes ~40s. On production it takes multiple minutes.
Stacked on top of #10962 for easier reviewing.

Description

• enable spring.main.lazy-initialization again.
• Make all the schedule services not listen to application ready event but to our custom full startup event that fires a bit later
• Refactored different services to reduce the number of services that need to instantiated at startup.
• Implemented a deferred eager initialization of beans. To avoid that many beans need to be initialized as soon as a request is made, we trigger bean initialization as soon as the startup is complete.

Steps for Testing

For manual testing you can approve both and this PR

• Deploy this branch and click around in the application to make sure nothing broke
• Optional: Check the logs in grafana and compare the full startup time with develop

Testserver States

You can manage test servers using Helios. Check environment statuses in the environment list. To deploy to a test server, go to the CI/CD page, find your PR or branch, and trigger the deployment.

Review Progress

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Test Coverage

unchanged

[github-actions]

End-to-End (E2E) Test Results Summary

	Tests	Passed ☑️	Skipped ⚠️	Failed ❌️	Time ⏱
End-to-End (E2E) Test Report	201 ran	197 passed	3 skipped	1 failed	57m 41s 430ms

Test	Result	Time ⏱
End-to-End (E2E) Test Report
e2e/exercise/programming/ProgrammingExerciseStaticCodeAnalysis.spec.ts
ts.Static code analysis tests › Configures SCA grading and makes a successful submission with SCA errors	❌ failure	2m 17s 308ms

[github-actions]

End-to-End (E2E) Test Results Summary

	Tests	Passed ✅	Skipped ⚠️	Failed	Time ⏱
End-to-End (E2E) Test Report	201 ran	198 passed	3 skipped	0 failed	59m 2s 482ms

Test	Result	Time ⏱
No test annotations available

[github-actions]

End-to-End (E2E) Test Results Summary

	Tests	Passed ☑️	Skipped ⚠️	Failed ❌️	Time ⏱
End-to-End (E2E) Test Report	201 ran	197 passed	3 skipped	1 failed	54m 13s 583ms

Test	Result	Time ⏱
End-to-End (E2E) Test Report
e2e/exercise/quiz-exercise/QuizExerciseParticipation.spec.ts
ts.Quiz Exercise Participation › DnD Quiz participation › Student can participate in DnD Quiz	❌ failure	2m 4s 559ms

[github-actions]

End-to-End (E2E) Test Results Summary

	Tests	Passed ✅	Skipped ⚠️	Failed	Time ⏱
End-to-End (E2E) Test Report	201 ran	198 passed	3 skipped	0 failed	55m 53s 202ms

Test	Result	Time ⏱
No test annotations available

[jfr2102]

code 👍

[HawKhiem]

Tested on TS3. So far no errors found

[DenizOzturk95]

I deployed and tested this in TS2 with multiple accounts, student, instructor and admin, and different exercises, and didn't observe anything broken.
But I had a weird helios issue, where despite building the image and deploying it, helios doesn't reflect it. it's stuck in this state (for the past 15 minutes).

I don't know whether this is due to helios, a fault of my own or something in your code that breaks it. I inspected the build logs on GitHub and to see it was deployed. I assume its probably just a visual bug, since as I wrote this review it updated.