perf(usage): guard redundant directory creation and permission checks on append

[chilung-cgu]

Summary

• Eliminates redundant synchronous filesystem calls in appendUsageEntry in src/usage/log.ts.
• Previously, every proxied request settlement invoked ensureUsageLogDir() (which ran mkdirSync(dir, { recursive: true }) and chmodSync(dir, 0o700)), followed by another unconditional chmodSync(path, 0o600). Under concurrent subagent workloads, these redundant synchronous syscalls blocked Bun event loop and delayed event dispatching.
• Introduces module-level state guards (ensuredUsageLogDir and ensuredUsageLogFile) so directory creation and file permissions are ensured once, avoiding redundant synchronous syscalls on subsequent appends.
• Adds ENOENT self-healing recovery: if the cached directory or log file is removed by rotation or cleanup during runtime, caches are cleared and the directory/file setup is retried once.
• Hardens test cleanup with try/finally around filesystem spies and aligns indentation in tests/usage/usage-log.test.ts.
• Adds cache reset hooks in resetUsageReadCacheForTests() for test isolation.
• Adds focused test coverage in tests/usage/usage-log.test.ts verifying consecutive append filesystem call limits and ENOENT recovery.

Verification

• bun run typecheck (passed, exit code 0)
• bun run privacy:scan (passed, exit code 0)
• bun test tests/usage/usage-log.test.ts (41 pass, 0 fail, 166 expect() calls)
• bun test tests/lab/core-lab-boundary.test.ts tests/ci-workflows/repo-hygiene.test.ts tests/usage/quota-reset-core-boundary.test.ts (52 pass, 0 fail, 131 expect() calls)
• Microbenchmark: 5,000 appends completed in 79.1 ms (~15.8 �s/op), reducing synchronous event loop blocking compared to the baseline (~20.8 �s/op).

Checklist

• Scope stays focused and avoids unrelated cleanup.
• Docs or release notes were updated when needed.
• Security-sensitive changes were reviewed for secrets, auth, and unsafe defaults.

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Summary by CodeRabbit

• Performance

  • Improved repeated usage logging by reducing unnecessary filesystem setup work, resulting in more efficient appends.

• Reliability

  • Preserved existing usage-log behavior while optimizing consecutive writes.
  • Usage logging now recovers automatically if its storage directory is removed between entries, preventing failures and preserving subsequent entries.

• Tests

  • Added coverage for efficient repeated writes and recovery after usage-log storage is deleted.

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📒 Files selected for processing (2)

• src/usage/log.ts
• tests/usage/usage-log.test.ts

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📝 Walkthrough

Walkthrough

The usage log writer caches ensured directory and file paths. Repeated appends skip redundant setup. An ENOENT retry clears both caches. Tests cover repeated appends and recovery after directory removal.

Changes

Usage log setup caching

Layer / File(s)	Summary
Cache filesystem setup and validate recovery src/usage/log.ts, tests/usage/usage-log.test.ts	appendUsageEntry and ensureUsageLogDir cache filesystem setup state. An ENOENT failure clears the caches before one retry. resetUsageReadCacheForTests clears the caches. Tests verify repeated-append call counts and recovery after directory removal.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Refactor

Merge Risk: ⚪ Minimal · up to a04af

The change includes cached setup reset and missing-path recovery coverage; no current merge-blocking risk is established.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main performance change: preventing redundant usage-log directory creation and permission checks during append operations.
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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[lidge-jun]

리뷰 · 우선순위 66 / 80

이 PR(#4795)은 chilung-cgu가 올린 좁은 성능 개선이다. 바꾸는 파일은 src/usage/log.ts와 tests/usage/usage-log.test.ts 두 개뿐이고, 베이스는 지금 dev tip인 ada3a9b1b (package 2.57.0, 마지막 머지 #4792 bare tool-name echo)에 맞춰져 있다. types.ts/config.ts 분할 캠페인이나 pre-split 경로를 건드리지 않으므로 close-don't-rebase 대상이 아니다.

지금 dev에서 appendUsageEntry는 프록시 요청이 끝날 때마다 불린다. 그 안에서 ensureUsageLogDir()가 매번 mkdirSync(dir, { recursive: true })와 chmodSync(dir, 0o700)을 돌리고, 이어서 appendFileSync 뒤에도 chmodSync(path, 0o600)을 또 한다. 한 번만 보면 싸 보이지만, 동시 서브에이전트가 많이 붙으면 Bun 이벤트 루프가 동기 파일시스템 호출에 막혀 이벤트 디스패치가 늦어진다. PR 본문이 말한 마이크로벤치(5,000 append, ~20.8µs → ~15.8µs)도 그 증상을 숫자로 보여 준 것이다.

고치는 방법은 모듈 변수 ensuredUsageLogDir / ensuredUsageLogFile이다. 디렉터리 경로가 이미 보장된 값과 같으면 ensureUsageLogDir가 바로 return하고, 파일 경로가 이미 보장된 값과 같으면 append 뒤 chmod를 건너뛴다. 테스트 격리용 resetUsageReadCacheForTests()에도 두 캐시를 null로 돌리는 훅을 넣었고, tests/usage/usage-log.test.ts에 연속 5번 append할 때 mkdirSync 1회·chmodSync 최대 2회를 잠그는 테스트를 추가했다. beforeEach가 이미 OPENCODEX_HOME을 임시 디렉터리로 바꾸고 resetUsageReadCacheForTests()를 호출하므로, 이 캐시 리셋이 없으면 테스트끼리 상태가 새어 나간다. getConfigDir()(src/config/paths.ts)도 OPENCODEX_HOME raw 문자열로 경로를 캐시하므로, 홈이 바뀌면 양쪽 캐시를 같이 비우는 선택이 맞다.

현재 dev 방향과 맞춰 보면, 최근 tip은 #4792 responses bare-echo, 그 아래 #4737 Codex 토큰 갱신, #4752 pw-stack(비전 사이드카·DeepSeek·Kimi·CodeBuddy scaffold)이다. 사용량 로그 핫패스 정리는 그 옆줄인 인프라 perf다. 같은 기여자의 #4740(서버 로그 단일 패스 쿼리)보다는 영향 범위가 작고, 그래도 “매 요청마다 동기 mkdir/chmod”는 실사용에서 체감될 수 있는 낭비라 유지할 가치가 있다. 체크리스트 4/4와 review-ready가 이미 붙어 있고, 로컬 typecheck·privacy·usage-log 테스트 통과를 본문에 적었다. 다만 GitHub mergeable_state는 아직 blocked라서, 저장소 규칙상 exact-head 호스티드 CI가 초록이 되기 전에는 머지하면 안 된다.

라인 src/usage/log.ts ensureUsageLogDir 조기 return - ensuredUsageLogDir === dir이면 recordOwnedConfigPath도 다시 안 부른다. 첫 보장 때는 기록되므로 보통은 괜찮지만, 프로세스 도중에 ownership 목록이 비워지는 경로가 있으면 그 목록과 캐시가 어긋날 수 있다.
라인 src/usage/log.ts ensuredUsageLogFile 가드 - 한 번 보장한 뒤에는 파일 권한을 다시 harden하지 않는다. 다른 프로세스가 모드를 풀어 놓거나, umask/플랫폼 차이로 첫 chmod가 실패했어도 이후에는 재시도하지 않는다. 성능과 “항상 0o600 재확인” 사이의 트레이드오프다.
경로/심볼 디렉터리 삭제 후 재생성 - 캐시가 채워진 뒤 사용자가 ~/.opencodex를 지우고 다시 쓰면, 예전 코드는 mkdirSync(recursive)로 복구했지만 지금은 조기 return으로 넘어가 appendFileSync가 실패할 수 있다. 운영에서 흔하진 않지만 fail-closed에 가깝다.
라인 tests/usage/usage-log.test.ts 새 테스트 들여쓰기 - describe 블록 안에서 test(...) 앞에 공백이 한 단 더 들어가 있어 주변 테스트와 정렬이 깨져 있다. 동작과는 무관하지만 리뷰·하이진에서 거슬린다.
경로/심볼 spy restore - mkdirSpy/chmodSpy를 mockRestore하기 전에 expect가 실패하면 스파이가 남을 수 있다. try/finally로 감싸면 더 안전하다.
경로/심볼 CI·mergeState - 호스티드 체크가 exact head 36de43a0b에서 아직 막혀 mergeable_state=blocked다. 로컬 통과만으로 머지하지 말고, exact-head CI 초록을 기다린다.

메인테이너의 판단이 필요한 지점

• “첫 보장 이후 chmod를 영구 생략”을 받아들일지, 아니면 주기적으로(또는 존재 확인 실패 시에만) 다시 harden할지.
• 홈 디렉터리가 런타임에 삭제·재생성되는 희귀 경로를 위해 캐시 히트 전 existsSync 한 번을 넣을지, 지금처럼 완전 생략할지.
• 호스티드 CI가 head SHA에서 모두 통과한 뒤에만 머지할지(권장), 로컬 통과 + review-ready만으로 올릴지.
• 프리뷰 배포는 계획에 없다. 이 PR은 usage append 핫패스만이라 미리보기 불필요.

너의 추천
범위가 좁고 tip에 맞춰진 알짜 perf라 유지한다. 들여쓰기와 spy finally만 정리한 뒤, exact-head 호스티드 CI가 초록이면 머지 후보로 둔다. 디렉터리 삭제 복구를 걱정하면 캐시 히트 전에 existsSync(dir) 실패 시에만 캐시를 비우는 한 줄을 추가하는 정도가 적당하다. types/config 분할이나 close-don’t-rebase 대상이 아니다. 중복 PR로 보이는 열린 이슈도 없다.

이 댓글은 grok-bot이 작성했습니다

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Actionable comments posted: 2

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Inline comments:
In `@src/usage/log.ts`:
- Line 860: Update appendUsageEntry and the cached-directory setup around
ensuredUsageLogDir so a missing cached directory is recovered: on ENOENT, clear
both setup caches, recreate the directory, and retry the append exactly once.
Add a regression test that removes the directory between two appendUsageEntry
calls and verifies the second append succeeds.

In `@tests/usage/usage-log.test.ts`:
- Around line 1018-1019: Update the test around the mkdirSync and chmodSync
spies to wrap the append and assertion logic in try/finally, restoring both
spies in the finally block so cleanup occurs even when the test body throws.

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[chilung-cgu]

PR has been updated to head c41735fb6 addressing all reviewer feedback:

1. ENOENT Recovery: In src/usage/log.ts, if appendUsageEntry encounters ENOENT (such as when the cached directory was removed by rotation/cleanup), both cached directory and file states are cleared, and directory setup + append are retried once.
2. Spy Cleanup: In tests/usage/usage-log.test.ts, wrapped the mkdirSync and chmodSync spy tests in try / finally to guarantee mockRestore() runs.
3. Indentation: Aligned test block indentation to 2 spaces.
4. Regression Test: Added unit test verifying recovery on ENOENT when directory is deleted between calls.

Local checks:

• bun run typecheck passed
• bun run privacy:scan passed
• bun test tests/usage/usage-log.test.ts passed (41 pass / 0 fail)