refactor(backend): collector/エラーコード/worker の保守性改善とテスト補強

[yusuke0610]

概要

バックエンドのリファクタリングレビュー（report/BE_report_20260609_2152.md）の採用項目を実装。重複の集約・認可ガードの共通化・worker ディスパッチの汎用化・エラーコード推定のテスト補強を行う。

変更内容

collector の重複集約（Medium）

• services/blog/collector.py の zenn/note/qiita 3 fetcher が重複させていた 8 キー記事 dict の構築を _build_article に集約。repositories/blog.py:_apply_article_payload が期待するキー集合との契約を docstring に明記
• 日付切り出し x[:10] if x else None を _truncate_date に集約（3→1）
• verify_user_exists の 3 連 if を _VERIFY_ENDPOINTS（platform→(URL, params)）テーブル + 単一 httpx 呼び出しへ畳み込み（挙動不変）

github_link router の認可ガード共通化（Medium）

• start/retry に重複していた github_id is None → 403 AUTH_REQUIRED を require_github_user 依存へ集約

worker ディスパッチの汎用化（Low・承認のうえ実施）

• execute_task の if task_type == GITHUB_LINK ハードコード分岐を get_handler(task_type).run(...) のデータ駆動ディスパッチへ。種別追加時に execute_task 無変更、ハンドラ未登録なら早期 return するため「分岐書き忘れで黙って completed」事故を構造的に除去
• dispatch seam の patch 対象を worker._run_github_link → GitHubLinkHandler.run へ移行。guard テスト test_all_task_types_have_dispatch_branch（source grep）を test_all_task_types_have_registered_handler（レジストリ登録チェック）へ強化

テスト補強（Test Add）

• tests/test_errors.py（新規）: infer_error_code の全分岐を parametrize で固定 + messages.json 文言ドリフト結合ガード（GitHub 未検出メッセージが INTERNAL_ERROR に劣化する脆さを検知）+ async ラッパテスト

挙動変更（要周知）

• require_github_user 依存化により、未連携ユーザーの POST /api/github-link/run・/run/retry は rate limit より前に 403 を返す（認可→レート制限の自然な順序）。API レスポンス契約（403/コード/メッセージ）は不変

破壊的変更

なし（DTO・API パス・env・依存追加なし）

検証

• make lint-backend: ✅ pass
• make test-backend: ✅ 428 passed（rate_limit テスト 1 件が認可順序変更で fail → 正規ヘルパへ修正し再 pass）
• make dupe-check: 77→77（解消分は jscpd 閾値未満で件数不変）

Follow-ups

• github_link の dispatch 節（payload+try/except）抽出は 2 箇所のため Rule of Three で保留（3 例目で抽出）
• _run_github_link シムは execute_task から未使用化（直接呼び出しテスト専用）→ 将来撤去余地あり（任意・別 PR）

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes

  • Strengthened authorization enforcement for GitHub-link operations.
  • Improved error handling and error-code inference across the platform.

• Refactor

  • Consolidated blog article collection logic for consistent data handling.
  • Centralized task dispatch mechanism for more reliable GitHub operation processing.

• Tests

  • Added comprehensive error-handling regression test coverage.
  • Updated security and integration tests to reflect improved authorization checks.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: bbae3043-e440-4cb0-8fe5-07cc9d758cec

📥 Commits

Reviewing files that changed from the base of the PR and between a093c4b and d9c388e.

📒 Files selected for processing (8)

• backend/app/routers/github_link.py
• backend/app/services/blog/collector.py
• backend/app/services/tasks/worker.py
• backend/tests/security/test_rate_limit.py
• backend/tests/test_blog_collector.py
• backend/tests/test_errors.py
• backend/tests/test_retry_flow.py
• backend/tests/test_worker/test_execute_task.py

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📝 Walkthrough

Walkthrough

This PR refactors task dispatch and authorization by introducing a shared GitHub-user authorization guard (require_github_user), converting task execution to a handler-registry pattern, refactoring blog-article construction into shared helpers, and adding comprehensive error-code regression tests with updated mocking throughout the test suite.

Changes

Task Dispatch and Authorization Refactoring

Layer / File(s)	Summary
Centralized GitHub User Authorization Guard backend/app/routers/github_link.py	require_github_user dependency validates user.github_id is present; both /api/github-link/run and /api/github-link/run/retry endpoints switch from get_current_user plus inline checks to the shared guard, centralizing AUTH_REQUIRED error response.
Handler Registry-Based Task Dispatch backend/app/services/tasks/worker.py	execute_task converts from per-task-type shim calls (e.g., _run_github_link) to generic get_handler(task_type) registry dispatch; _run_github_link is retained as a direct test entry point.
Error Code Inference Regression Tests backend/tests/test_errors.py	New module adds comprehensive tests for infer_error_code, infer_async_error_code, and resolve_async_error_code, with explicit contract locks for GitHub "user not found" substring matching and status-to-code mappings.
Task Dispatch Unit Test Updates backend/tests/test_worker/test_execute_task.py	Tests switch from mocking _run_github_link to mocking GitHubLinkHandler.run; new test validates all TaskType values are registered in the handler registry; error and success paths align with the new architecture.
Integration and Rate Limit Test Updates backend/tests/test_retry_flow.py, backend/tests/security/test_rate_limit.py	test_retry_flow.py mocks GitHubLinkHandler.run via patch.object; test_rate_limit.py constructs requests with github_id header instead of database user setup, ensuring authorization does not block rate-limiter validation.

Blog Collector Service Refactoring

Layer / File(s)	Summary
Article Building and Verification Helpers backend/app/services/blog/collector.py	Introduces _VERIFY_ENDPOINTS mapping for platform-specific user-verification templates, _truncate_date for consistent ISO-date truncation, and _build_article shared helper for standardized article dict construction.
Platform-Specific Article Fetching Updates backend/app/services/blog/collector.py, backend/tests/test_blog_collector.py	fetch_zenn_articles, fetch_note_articles, and fetch_qiita_articles call _build_article with platform-extracted fields; verify_user_exists uses centralized endpoint lookup instead of per-platform request branching; test assertion updated to expect params=None in HTTP GET call.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• yusuke0610/devforge#270: Modifies retry_github_link endpoint error message construction, which shares the updated auth dependency guard introduced in this PR.

Poem

A rabbit hops through the refactor maze,
Centralizing guards that guard all days,
Handlers registry keeps tasks in line,
Blog collectors bloom in helpers' design. 🐰✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main refactoring effort across three backend components (collector/error-code/worker) with a focus on maintainability improvements and test strengthening, directly matching the PR's core objectives.
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.

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✨ 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 refactor/be-collector-errcode-worker

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