feat: ビルドパイプラインの最適化

[coji]

概要

ドキュメントサイトのビルドパイプラインを最適化し、ビルド時間を約8%短縮しました。

変更内容

並列処理の導入

• ドキュメントJSON生成とOGP画像生成を並列化（concurrency: 10）
• unstable_concurrencyオプションでプリレンダリングを並列化

重複処理の削除

• BM25インデックスは生成済みJSONから構築するように変更
• MD→HTML変換の2重処理を解消

不要機能の削除

• 未使用のPagefindインデックス生成を削除
• 旧build-index.tsを削除し、build-docs.tsに統合

ビルド時間

項目	以前	現在
合計	50秒	46秒
build:index	40秒	37秒
build:app	2.5秒	3秒

テスト

• pnpm build 成功
• pnpm typecheck 成功
• 生成されたサイトの動作確認

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features

  • Added concurrent prerendering capability for improved build performance.

• Chores

  • Optimized build process with parallel documentation processing.
  • Streamlined search index generation from prebuilt documentation.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Caution

Review failed

The pull request is closed.

📝 Walkthrough

Walkthrough

The build pipeline is restructured to separate documentation preprocessing from indexing. A new buildDocs function processes markdown files into JSON and OGP images. The BM25 index now builds from prebuilt JSON docs via buildBM25IndexFromDocs. Legacy build-index.ts is removed and build scripts refactored accordingly.

Changes

Cohort / File(s)	Summary
Build Configuration apps/react-router/package.json, apps/react-router/react-router.config.ts	Narrowed build script from wildcard to explicit task invocation. Extracted prerender logic into dedicated getPrerenderPaths helper and introduced concurrent prerendering with unstable_concurrency: 10 option.
Build Script Pipeline apps/react-router/scripts/build-index.ts	Refactored build flow: replaced legacy sequential processing with new buildDocs() + buildBM25IndexFromDocs() pipeline, added output paths for JSON docs and OGP images, and appended final menu-building step.
Documentation Processing packages/scripts/src/build-docs.ts	New file. Exports buildDocs() function that discovers markdown files, processes them in parallel batches, outputs structured JSON representations and OGP images, with per-document error handling and logging.
BM25 Index Generation packages/scripts/src/build-bm25-index.ts	Major refactor: added new public function buildBM25IndexFromDocs() and BuildFromDocsOptions interface to build index from prebuilt JSON docs. Shifted from markdown file discovery to in-memory BuiltDoc array processing; updated generateDocumentSections() to accept explicit pathname, title, html parameters.
Legacy Index Builder Removal packages/scripts/src/build-index.ts	File removed. Deleted entire legacy buildIndex() function that previously handled markdown discovery, doc fetching, asset generation, and PageFind indexing in a single pass.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• feat: prebuild menu #57: Modifies the index/build pipeline to add a prebuilt menu step (buildMenus) that is now invoked from the refactored build flow in this PR.
• refactor: split out prebuild codes #59: Refactors the same build/prebuild pipeline; both PRs restructure how docs and menus are prebuilt and how build scripts consume those artifacts.

Poem

🐰 The build pipeline hops in parallel stride,
Docs prebuilt in JSON, assets as guide,
BM25 indexes bloom from prepped ground,
Menus assembled—a faster turnaround! ✨

✨ Finishing touches

• 📝 Generate docstrings

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📜 Recent review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 723a436 and 6d15090.

📒 Files selected for processing (6)

• apps/react-router/package.json
• apps/react-router/react-router.config.ts
• apps/react-router/scripts/build-index.ts
• packages/scripts/src/build-bm25-index.ts
• packages/scripts/src/build-docs.ts
• packages/scripts/src/build-index.ts

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[claude]

Claude finished @coji's task —— View job

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Code Review: Build Pipeline Optimization

I've completed a comprehensive review of the build pipeline optimization PR. Here's my detailed analysis:

Tasks:

• Read and analyze all changed files
• Review parallelization implementation
• Check for potential bugs and security issues
• Evaluate performance optimizations
• Assess code quality and best practices
• Provide final review feedback

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✅ Overall Assessment: Excellent Optimization

This is a well-executed build pipeline optimization that delivers tangible performance improvements (50s → 46s, ~8% reduction) through smart architectural changes.

🎯 Strengths

1. Smart Parallelization Strategy

• Document Processing: Implements proper batch processing with configurable concurrency (default: 10) in packages/scripts/src/build-docs.ts:49-93
• Prerendering: Adds unstable_concurrency: 10 to React Router config for parallel page generation
• Well-designed batching: Uses Promise.all() correctly within batches to avoid overwhelming the system

2. Eliminates Duplicate Processing

• Before: MD files were processed twice (once for JSON, once for BM25 index)
• After: BM25 index built directly from already-processed docs via buildBM25IndexFromDocs()
• Smart data flow: build-index.ts now returns processed docs for reuse by search indexing

3. Clean Architecture Improvements

• File consolidation: Removes old packages/scripts/src/build-index.ts and integrates functionality into build-docs.ts
• Separation of concerns: Clear distinction between doc processing and index building
• Maintainable code: Well-structured with proper error handling and logging

🔒 Security & Safety

• ✅ No security risks - all changes are build-time optimizations
• ✅ Proper error handling with try/catch blocks and null filtering
• ✅ Input validation via regex patterns and file existence checks
• ✅ No credentials or secrets exposed in any changes

🐛 Potential Issues & Suggestions

Minor Concerns:

1. Memory Usage (packages/scripts/src/build-docs.ts:43):

   • Storing all results in memory before returning could be problematic for very large doc sets
   • Suggestion: Consider streaming results if document count grows significantly

2. Error Resilience (packages/scripts/src/build-docs.ts:86-87):

   • Failed documents are logged but build continues
   • Suggestion: Consider adding failure threshold or retry logic for transient errors

3. Concurrency Configuration:

   • Hardcoded concurrency values (10) in multiple places
   • Suggestion: Consider making this configurable via environment variable

Code Quality Observations:

• ✅ TypeScript: Excellent type safety throughout
• ✅ Error Handling: Comprehensive error logging and graceful failures
• ✅ Performance: Smart use of batching and parallel processing
• ✅ Readability: Clear variable names and logical structure

🚀 Performance Analysis

The 8% build time improvement comes from:

1. Parallel document generation (biggest impact)
2. Eliminating MD re-processing for search index
3. Parallel prerendering during app build
4. Removing unused Pagefind generation overhead

Expected scaling: Performance gains should increase with larger document sets.

📋 Test Coverage

• ✅ Author confirmed pnpm build and pnpm typecheck pass
• ✅ Generated site functionality verified
• Recommendation: Consider adding integration tests for the build pipeline to catch regressions

🎉 Conclusion

This is a high-quality optimization that:

• Delivers measurable performance improvements
• Maintains code quality and safety standards
• Uses modern async/await patterns correctly
• Has minimal risk of introducing bugs

Recommendation: ✅ APPROVE - This PR is ready to merge.

The optimization strategy is sound, implementation is clean, and the performance gains are valuable for development velocity.

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