Initial commit: import from sinmb79/Gov-chat-bot

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/services/idempotency.py

@@ -0,0 +1,28 @@
+import json
+from typing import Optional
+
+
+class IdempotencyCache:
+    def __init__(self, redis_client):
+        self.redis = redis_client
+        self.ttl = 60  # 기본 TTL (Phase 0B에서 settings로 교체 예정)
+
+    def _key(self, tenant_id: str, request_id: str) -> str:
+        return f"idempotency:{tenant_id}:{request_id}"
+
+    async def get(self, tenant_id: str, request_id: Optional[str]) -> Optional[dict]:
+        if request_id is None:
+            return None
+        raw = await self.redis.get(self._key(tenant_id, request_id))
+        if raw is None:
+            return None
+        return json.loads(raw)
+
+    async def set(self, tenant_id: str, request_id: Optional[str], result_dict: dict) -> None:
+        if request_id is None:
+            return
+        await self.redis.setex(
+            self._key(tenant_id, request_id),
+            self.ttl,
+            json.dumps(result_dict),
+        )