Sprint 97 — Programmers Migration Completion: GitHub Worker + Submission MQ + AI Prompt + Tags Crawler + WCAG

Background

Final sprint of the 3-sprint Programmers migration roadmap (Sprint 95 backend infra → Sprint 96 frontend UX → Sprint 97 completion). This sprint closes all remaining carry-over items: GitHub Worker platform support, Submission MQ event sourcePlatform field, AI feedback prompt platform context injection, Programmers tags 2nd-pass crawler, and WCAG accessibility check script.

Goals

1. GitHub Worker: formatPlatform() 'programmers' → 'PROGRAMMERS' + prg_ filename prefix
2. Submission MQ event: add sourcePlatform field to RabbitMQ submission event
3. AI analysis: inject sourcePlatform into system prompt dynamically
4. Tags crawler: 2nd-pass crawl for Programmers problem detail pages (breadcrumb tags)
5. WCAG check: automated accessibility compliance verification script

Work Summary

Changes

GitHub Worker — formatPlatform()

// services/github-worker/src/utils/format-platform.ts
export function formatPlatform(raw: string): string {
  switch (raw.toLowerCase()) {
    case 'boj': return 'BOJ';
    case 'programmers': return 'PROGRAMMERS';
    default: throw new Error(`Unknown platform: ${raw}`);
  }
}

Filename prefix logic:

const prefix = sourcePlatform === 'PROGRAMMERS' ? 'prg_' : 'boj_';
const filename = `${prefix}${problemId}_${slug}.md`;

Submission MQ Event

// Before
interface SubmissionCreatedEvent {
  submissionId: string;
  problemId: string;
  userId: string;
  language: string;
}

// After
interface SubmissionCreatedEvent {
  submissionId: string;
  problemId: string;
  userId: string;
  language: string;
  sourcePlatform: 'BOJ' | 'PROGRAMMERS';  // added
}

AI analysis consumer reads sourcePlatform from the event.

AI Analysis — Dynamic Platform Context

# services/ai-analysis/src/prompts.py
def get_system_prompt(language: str, source_platform: str) -> str:
    platform_context = (
        "This problem is from Programmers (Korean competitive programming platform)."
        if source_platform == "PROGRAMMERS"
        else "This problem is from Baekjoon Online Judge (BOJ)."
    )
    return BASE_SYSTEM_PROMPT.format(
        language=language,
        platform_context=platform_context,
    )

Tags 2nd-Pass Crawler

• Crawled individual problem detail pages at programmers.co.kr/learn/courses/30/lessons/{problemId}
• Extracted category tags from breadcrumb navigation
• Updated services/gateway/data/programmers-problems.json — tags populated for 298/373 problems
• 75 problems had no breadcrumb tags (unclassified)

WCAG Check Script

• scripts/check-wcag.mjs — crawls rendered pages with axe-core via Playwright
• Checks: color contrast ratio ≥ 4.5:1, alt text for images, ARIA labels, keyboard navigation
• Run in CI as non-blocking warning (sprint 97: advisory only; hard gate in Sprint 100+)

Verification

Decisions

• prg_ prefix for Programmers files: Distinguishes Programmers solutions from BOJ (boj_) in GitHub repositories. Consistent with existing BOJ pattern.
• sourcePlatform added to MQ event (not looked up from DB): The submission event already has problemId but looking up platform requires an extra DB query in the consumer. Passing it in the event follows the "fat event" pattern — consumer is self-contained.
• Tags partial coverage accepted: 298/373 tags populated. 75 unclassified problems have no Programmers category breadcrumb. Accepted as-is; display falls back to "Unclassified" label.
• WCAG advisory-only in Sprint 97: Hard gate would block sprint completion. Advisory first, measure baseline, then enforce in Sprint 100+.

Lessons Learned

• "Fat event" pattern prevents consumer DB roundtrips: Including sourcePlatform in the MQ event means the AI analysis consumer doesn't need to query the problem service. Event consumers should be self-contained.
• Tags crawler second pass is significantly slower: Individual page crawls at 373 URLs with 300–500ms delay = ~3 minutes. Batching or parallel crawling with rate limiting is preferable for future data enrichment.
• WCAG baseline before enforcement: Measuring violations first (advisory mode) reveals the actual baseline. Enforcing without baseline data creates unpredictable CI failures.
• 3-sprint migration roadmap conclusion: Sprint 95 (infra) → 96 (frontend) → 97 (completion) pattern proved effective. Each sprint was independently deployable and had clear scope.

Migration Complete ✅

The BOJ → Programmers migration roadmap is fully closed. All services support both platforms:

• Gateway: /api/external/programmers/* and /api/external/boj/*
• Frontend: platform toggle in AddProblemModal
• GitHub Worker: prg_ prefix + formatPlatform()
• Submission: sourcePlatform in MQ events
• AI Analysis: platform-aware system prompts
• Data: 373 problems with 298 tags populated