feat: Conversation sqlite 영구화 — 재시작에도 컨텍스트 유지

- db/database.py: conversation_messages 테이블 + save/load/cleanup 헬퍼
- conversation.py: write-through (memory + DB) + lazy load on first access
  - 메모리 캐시 1시간 TTL, DB 7일 보관
  - add/get/format_for_prompt가 async로 변경
- worker.py: 모든 conversation_store 호출에 await 추가
- main.py lifespan에 startup cleanup 호출 (7일 이상 정리)

서버 재시작 후 "방금 그거 더 자세히" 같은 후속 질문이 컨텍스트 유지

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

nanoclaude/db/database.py

@@ -1,4 +1,6 @@
-"""aiosqlite DB — 요청/응답 로깅 및 메트릭."""
+"""aiosqlite DB — 요청/응답 로깅 + 대화 영구화."""
+
+from time import time
 
 import aiosqlite
 
@@ -23,6 +25,17 @@ CREATE TABLE IF NOT EXISTS request_logs (
 
 CREATE INDEX IF NOT EXISTS idx_logs_job ON request_logs(job_id);
 CREATE INDEX IF NOT EXISTS idx_logs_created ON request_logs(created_at);
+
+CREATE TABLE IF NOT EXISTS conversation_messages (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id TEXT NOT NULL,
+    role TEXT NOT NULL,
+    content TEXT NOT NULL,
+    created_at REAL NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_conv_user ON conversation_messages(user_id, created_at DESC);
+CREATE INDEX IF NOT EXISTS idx_conv_created ON conversation_messages(created_at);
 """
 
 # Phase 1 → Phase 2 마이그레이션 (이미 존재하면 무시)
@@ -55,6 +68,39 @@ async def log_request(job_id: str, message: str, model: str, created_at: float):
         await db.commit()
 
 
+async def save_conversation_message(user_id: str, role: str, content: str, created_at: float):
+    """대화 메시지 저장."""
+    async with aiosqlite.connect(settings.db_path) as db:
+        await db.execute(
+            "INSERT INTO conversation_messages (user_id, role, content, created_at) VALUES (?, ?, ?, ?)",
+            (user_id, role, content, created_at),
+        )
+        await db.commit()
+
+
+async def load_conversation_messages(user_id: str, since: float, limit: int = 40) -> list[dict]:
+    """user_id의 최근 메시지 로드 (오래된 순)."""
+    async with aiosqlite.connect(settings.db_path) as db:
+        db.row_factory = aiosqlite.Row
+        cursor = await db.execute(
+            "SELECT role, content, created_at FROM conversation_messages "
+            "WHERE user_id=? AND created_at >= ? ORDER BY created_at DESC LIMIT ?",
+            (user_id, since, limit),
+        )
+        rows = await cursor.fetchall()
+        # 오래된 순으로 뒤집기
+        return [{"role": r["role"], "content": r["content"], "created_at": r["created_at"]} for r in reversed(rows)]
+
+
+async def cleanup_old_conversations(days: int = 7) -> int:
+    """N일 이상 오래된 대화 삭제. 삭제된 행 수 반환."""
+    cutoff = time() - (days * 86400)
+    async with aiosqlite.connect(settings.db_path) as db:
+        cursor = await db.execute("DELETE FROM conversation_messages WHERE created_at < ?", (cutoff,))
+        await db.commit()
+        return cursor.rowcount
+
+
 async def log_completion(
     job_id: str,
     status: str,

nanoclaude/main.py

@@ -24,6 +24,15 @@ logging.basicConfig(
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     await init_db()
+    # 7일 이상 오래된 대화 정리
+    try:
+        from db.database import cleanup_old_conversations
+        deleted = await cleanup_old_conversations(days=7)
+        if deleted:
+            import logging
+            logging.getLogger(__name__).info("Cleaned up %d old conversation messages", deleted)
+    except Exception:
+        pass
     backend_registry.init_from_settings(settings)
     backend_registry.start_health_loop(settings.health_check_interval)
     jq_module.init_queue(settings.max_concurrent_jobs)

nanoclaude/services/conversation.py

@@ -1,14 +1,18 @@
-"""Conversation — user별 최근 대화 기억."""
+"""Conversation — user별 최근 대화 기억 (메모리 캐시 + sqlite write-through)."""
 
 from __future__ import annotations
 
+import logging
 from collections import defaultdict
 from dataclasses import dataclass, field
 from time import time
 
-MAX_HISTORY = 10  # user당 최근 대화 수
-HISTORY_TTL = 3600.0  # 1시간 이후 대화 만료
+logger = logging.getLogger(__name__)
+
+MAX_HISTORY = 10  # 메모리 캐시 user당 최근 대화 수
+HISTORY_TTL = 3600.0  # 1시간 이후 메모리 만료 (DB는 7일 보관)
 DRAFT_TTL = 300.0  # pending_draft 5분 만료
+DB_LOAD_LIMIT = 40  # DB lazy load 시 최대 메시지 수
 
 
 @dataclass
@@ -21,27 +25,56 @@ class Message:
 class ConversationStore:
     def __init__(self) -> None:
         self._history: dict[str, list[Message]] = defaultdict(list)
+        self._loaded_users: set[str] = set()  # DB lazy load 완료한 user_id
         self._pending_drafts: dict[str, tuple[dict, float]] = {}  # user_id → (draft_data, created_at)
 
-    def add(self, user_id: str, role: str, content: str) -> None:
+    async def add(self, user_id: str, role: str, content: str) -> None:
+        """메모리 + DB write-through."""
+        from db.database import save_conversation_message
+        msg = Message(role=role, content=content)
+
+        # 메모리 캐시
         msgs = self._history[user_id]
-        msgs.append(Message(role=role, content=content))
-        # 최대 개수 제한
+        msgs.append(msg)
         if len(msgs) > MAX_HISTORY:
             self._history[user_id] = msgs[-MAX_HISTORY:]
 
-    def get(self, user_id: str) -> list[Message]:
-        """만료되지 않은 최근 대화 반환."""
+        # DB write-through (실패해도 메모리에는 남음)
+        try:
+            await save_conversation_message(user_id, role, content, msg.timestamp)
+        except Exception:
+            logger.warning("Failed to persist conversation for %s", user_id, exc_info=True)
+
+    async def get(self, user_id: str) -> list[Message]:
+        """만료되지 않은 최근 대화. 메모리 비어있으면 DB lazy load."""
+        from db.database import load_conversation_messages
         now = time()
+
+        # 메모리 캐시에서 fresh 한 것만
         msgs = self._history.get(user_id, [])
-        # TTL 필터
         fresh = [m for m in msgs if now - m.timestamp < HISTORY_TTL]
+
+        # 메모리 비어있고 DB lazy load 안 했으면 DB에서 가져옴
+        if not fresh and user_id not in self._loaded_users:
+            self._loaded_users.add(user_id)
+            since = now - HISTORY_TTL
+            try:
+                db_msgs = await load_conversation_messages(user_id, since, limit=DB_LOAD_LIMIT)
+                fresh = [
+                    Message(role=m["role"], content=m["content"], timestamp=m["created_at"])
+                    for m in db_msgs
+                ]
+                if fresh:
+                    logger.info("Loaded %d messages from DB for %s", len(fresh), user_id)
+            except Exception:
+                logger.warning("Failed to load conversation from DB for %s", user_id, exc_info=True)
+
         self._history[user_id] = fresh
         return fresh
 
-    def format_for_prompt(self, user_id: str) -> str:
+    async def format_for_prompt(self, user_id: str) -> str:
         """EXAONE에 전달할 대화 이력 포맷."""
-        msgs = self.get(user_id)
+        msgs = await self.get(user_id)
         lines = []
         for m in msgs[-6:]:  # 최근 6개만
             prefix = "사용자" if m.role == "user" else "이드"

nanoclaude/services/worker.py

@@ -240,7 +240,7 @@ async def run(job: Job) -> None:
             kst = timezone(timedelta(hours=9))
             now_kst = datetime.now(kst)
             now_str = now_kst.strftime("%Y년 %m월 %d일 %H:%M (%A) KST")
-            history = conversation_store.format_for_prompt(user_id)
+            history = await conversation_store.format_for_prompt(user_id)
             classify_input = f"[현재 시간]\n{now_str}\n\n"
             if history:
                 classify_input += f"[대화 이력]\n{history}\n\n"
@@ -268,7 +268,7 @@ async def run(job: Job) -> None:
         logger.info("Job %s classified as '%s'", job.id, action)
 
         # 대화 기록: 사용자 메시지
-        conversation_store.add(user_id, "user", job.message)
+        await conversation_store.add(user_id, "user", job.message)
 
         collected: list[str] = []
 
@@ -281,7 +281,7 @@ async def run(job: Job) -> None:
             status_text = await _build_system_status(force_measure=True)
             collected.append(status_text)
             await state_stream.push(job.id, "result", {"content": status_text})
-            conversation_store.add(user_id, "assistant", status_text)
+            await conversation_store.add(user_id, "assistant", status_text)
 
         elif action == "tools":
             # === TOOLS: 도구 실행 ===
@@ -299,7 +299,7 @@ async def run(job: Job) -> None:
                     response = "확인할 일정이 없습니다. 다시 요청해주세요."
                     collected.append(response)
                     await state_stream.push(job.id, "result", {"content": response})
-                    conversation_store.add(user_id, "assistant", response)
+                    await conversation_store.add(user_id, "assistant", response)
                 else:
                     try:
                         result = await asyncio.wait_for(execute_tool(tool_name, operation, draft), timeout=TOOL_TIMEOUT)
@@ -309,7 +309,7 @@ async def run(job: Job) -> None:
                     response = result.get("summary", "") if result["ok"] else result.get("error", "⚠️ 오류")
                     collected.append(response)
                     await state_stream.push(job.id, "result", {"content": response})
-                    conversation_store.add(user_id, "assistant", response)
+                    await conversation_store.add(user_id, "assistant", response)
             else:
                 # 일반 도구 실행
                 try:
@@ -355,13 +355,13 @@ async def run(job: Job) -> None:
                         collected.append(response)
                         await state_stream.push(job.id, "result", {"content": response})
 
-                conversation_store.add(user_id, "assistant", "".join(collected))
+                await conversation_store.add(user_id, "assistant", "".join(collected))
 
         elif action == "clarify":
             # === CLARIFY: 추가 질문 ===
             collected.append(response_text)
             await state_stream.push(job.id, "result", {"content": response_text})
-            conversation_store.add(user_id, "assistant", response_text)
+            await conversation_store.add(user_id, "assistant", response_text)
 
         elif action == "route" and settings.pipeline_enabled and backend_registry.is_healthy("reasoner"):
             # === ROUTE: Gemma reasoning ===
@@ -396,7 +396,7 @@ async def run(job: Job) -> None:
             reasoner_system = f"{backend_registry.reasoner.system_prompt}\n\n현재 시간: {now_kst} (한국 표준시)"
 
             # 대화 이력을 OpenAI messages 형식으로 변환 (현재 user 메시지 포함됨)
-            history_msgs = conversation_store.get(user_id)[-10:]
+            history_msgs = (await conversation_store.get(user_id))[-10:]
             reasoner_messages = [{"role": "system", "content": reasoner_system}]
             for m in history_msgs:
                 reasoner_messages.append({"role": m.role, "content": m.content})
@@ -419,7 +419,7 @@ async def run(job: Job) -> None:
                     return
 
             if collected:
-                conversation_store.add(user_id, "assistant", "".join(collected))
+                await conversation_store.add(user_id, "assistant", "".join(collected))
 
         else:
             # === DIRECT: EXAONE 직접 응답 ===
@@ -435,7 +435,7 @@ async def run(job: Job) -> None:
                     return
 
             if collected:
-                conversation_store.add(user_id, "assistant", "".join(collected))
+                await conversation_store.add(user_id, "assistant", "".join(collected))
 
         # --- Complete ---
         if not collected: