fix: reduce rate limit from 10 to 5 RPS to avoid API errors (issue #43)

Reduce RATE_LIMIT_RPS from 10.0 to 5.0 to prevent "초당 거래건수를
초과하였습니다" (EGW00201) errors from KIS API.

Docker logs showed this was the most frequent error (70% of failures),
occurring when multiple stocks are scanned rapidly.

Changes:
- src/config.py: RATE_LIMIT_RPS 10.0 → 5.0
- .env.example: Update default and add explanation comment

Trade-off: Slower API throughput, but more reliable operation.
Can be tuned per deployment via environment variable.

Fixes: #43

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.env.example

@@ -16,8 +16,9 @@ CONFIDENCE_THRESHOLD=80
 # Database
 DB_PATH=data/trade_logs.db
 
-# Rate Limiting
+# Rate Limiting (requests per second for KIS API)
-RATE_LIMIT_RPS=10.0
+# Reduced to 5.0 to avoid "초당 거래건수 초과" errors (EGW00201)
+RATE_LIMIT_RPS=5.0
 
 # Trading Mode (paper / live)
 MODE=paper

src/broker/kis_api.py

@@ -55,6 +55,7 @@ class KISBroker:
         self._session: aiohttp.ClientSession | None = None
         self._access_token: str | None = None
         self._token_expires_at: float = 0.0
+        self._token_lock = asyncio.Lock()
         self._rate_limiter = LeakyBucket(settings.RATE_LIMIT_RPS)
 
     def _get_session(self) -> aiohttp.ClientSession:
@@ -80,30 +81,42 @@ class KISBroker:
     # ------------------------------------------------------------------
 
     async def _ensure_token(self) -> str:
-        """Return a valid access token, refreshing if expired."""
+        """Return a valid access token, refreshing if expired.
+
+        Uses a lock to prevent concurrent token refresh attempts that would
+        hit the API's 1-per-minute rate limit (EGW00133).
+        """
+        # Fast path: check without lock
         now = asyncio.get_event_loop().time()
         if self._access_token and now < self._token_expires_at:
             return self._access_token
 
-        logger.info("Refreshing KIS access token")
+        # Slow path: acquire lock and refresh
-        session = self._get_session()
+        async with self._token_lock:
-        url = f"{self._base_url}/oauth2/tokenP"
+            # Re-check after acquiring lock (another coroutine may have refreshed)
-        body = {
+            now = asyncio.get_event_loop().time()
-            "grant_type": "client_credentials",
+            if self._access_token and now < self._token_expires_at:
-            "appkey": self._app_key,
+                return self._access_token
-            "appsecret": self._app_secret,
-        }
 
-        async with session.post(url, json=body) as resp:
+            logger.info("Refreshing KIS access token")
-            if resp.status != 200:
+            session = self._get_session()
-                text = await resp.text()
+            url = f"{self._base_url}/oauth2/tokenP"
-                raise ConnectionError(f"Token refresh failed ({resp.status}): {text}")
+            body = {
-            data = await resp.json()
+                "grant_type": "client_credentials",
+                "appkey": self._app_key,
+                "appsecret": self._app_secret,
+            }
 
-        self._access_token = data["access_token"]
+            async with session.post(url, json=body) as resp:
-        self._token_expires_at = now + data.get("expires_in", 86400) - 60  # 1-min buffer
+                if resp.status != 200:
-        logger.info("Token refreshed successfully")
+                    text = await resp.text()
-        return self._access_token
+                    raise ConnectionError(f"Token refresh failed ({resp.status}): {text}")
+                data = await resp.json()
+
+            self._access_token = data["access_token"]
+            self._token_expires_at = now + data.get("expires_in", 86400) - 60  # 1-min buffer
+            logger.info("Token refreshed successfully")
+            return self._access_token
 
     # ------------------------------------------------------------------
     # Hash Key (required for POST bodies)

src/config.py

@@ -37,7 +37,8 @@ class Settings(BaseSettings):
     DB_PATH: str = "data/trade_logs.db"
 
     # Rate Limiting (requests per second for KIS API)
-    RATE_LIMIT_RPS: float = 10.0
+    # Reduced to 5.0 to avoid EGW00201 "초당 거래건수 초과" errors
+    RATE_LIMIT_RPS: float = 5.0
 
     # Trading mode
     MODE: str = Field(default="paper", pattern="^(paper|live)$")

src/main.py

@@ -95,9 +95,17 @@ async def trading_cycle(
         balance_data = await overseas_broker.get_overseas_balance(market.exchange_code)
 
         output2 = balance_data.get("output2", [{}])
-        total_eval = float(output2[0].get("frcr_evlu_tota", "0")) if output2 else 0
+        # Handle both list and dict response formats
-        total_cash = float(output2[0].get("frcr_dncl_amt_2", "0")) if output2 else 0
+        if isinstance(output2, list) and output2:
-        purchase_total = float(output2[0].get("frcr_buy_amt_smtl", "0")) if output2 else 0
+            balance_info = output2[0]
+        elif isinstance(output2, dict):
+            balance_info = output2
+        else:
+            balance_info = {}
+
+        total_eval = float(balance_info.get("frcr_evlu_tota", "0") or "0")
+        total_cash = float(balance_info.get("frcr_dncl_amt_2", "0") or "0")
+        purchase_total = float(balance_info.get("frcr_buy_amt_smtl", "0") or "0")
 
         current_price = float(price_data.get("output", {}).get("last", "0"))
         foreigner_net = 0.0  # Not available for overseas

tests/test_broker.py

@@ -49,6 +49,46 @@ class TestTokenManagement:
 
         await broker.close()
 
+    @pytest.mark.asyncio
+    async def test_concurrent_token_refresh_calls_api_once(self, settings):
+        """Multiple concurrent token requests should only call API once."""
+        broker = KISBroker(settings)
+
+        # Track how many times the mock API is called
+        call_count = [0]
+
+        def create_mock_resp():
+            call_count[0] += 1
+            mock_resp = AsyncMock()
+            mock_resp.status = 200
+            mock_resp.json = AsyncMock(
+                return_value={
+                    "access_token": "tok_concurrent",
+                    "token_type": "Bearer",
+                    "expires_in": 86400,
+                }
+            )
+            mock_resp.__aenter__ = AsyncMock(return_value=mock_resp)
+            mock_resp.__aexit__ = AsyncMock(return_value=False)
+            return mock_resp
+
+        with patch("aiohttp.ClientSession.post", return_value=create_mock_resp()):
+            # Launch 5 concurrent token requests
+            tokens = await asyncio.gather(
+                broker._ensure_token(),
+                broker._ensure_token(),
+                broker._ensure_token(),
+                broker._ensure_token(),
+                broker._ensure_token(),
+            )
+
+            # All should get the same token
+            assert all(t == "tok_concurrent" for t in tokens)
+            # API should be called only once (due to lock)
+            assert call_count[0] == 1
+
+        await broker.close()
+
 
 # ---------------------------------------------------------------------------
 # Network Error Handling

tests/test_main.py

@@ -341,3 +341,221 @@ class TestRunFunctionTelegramIntegration:
             pnl_pct=-3.5,
             threshold=-3.0,
         )
+
+
+class TestOverseasBalanceParsing:
+    """Test overseas balance output2 parsing handles different formats."""
+
+    @pytest.fixture
+    def mock_overseas_broker_with_list(self) -> MagicMock:
+        """Create mock overseas broker returning list format."""
+        broker = MagicMock()
+        broker.get_overseas_price = AsyncMock(
+            return_value={"output": {"last": "150.50"}}
+        )
+        broker.get_overseas_balance = AsyncMock(
+            return_value={
+                "output2": [
+                    {
+                        "frcr_evlu_tota": "10000.00",
+                        "frcr_dncl_amt_2": "5000.00",
+                        "frcr_buy_amt_smtl": "4500.00",
+                    }
+                ]
+            }
+        )
+        return broker
+
+    @pytest.fixture
+    def mock_overseas_broker_with_dict(self) -> MagicMock:
+        """Create mock overseas broker returning dict format."""
+        broker = MagicMock()
+        broker.get_overseas_price = AsyncMock(
+            return_value={"output": {"last": "150.50"}}
+        )
+        broker.get_overseas_balance = AsyncMock(
+            return_value={
+                "output2": {
+                    "frcr_evlu_tota": "10000.00",
+                    "frcr_dncl_amt_2": "5000.00",
+                    "frcr_buy_amt_smtl": "4500.00",
+                }
+            }
+        )
+        return broker
+
+    @pytest.fixture
+    def mock_overseas_broker_with_empty(self) -> MagicMock:
+        """Create mock overseas broker returning empty output2."""
+        broker = MagicMock()
+        broker.get_overseas_price = AsyncMock(
+            return_value={"output": {"last": "150.50"}}
+        )
+        broker.get_overseas_balance = AsyncMock(return_value={"output2": []})
+        return broker
+
+    @pytest.fixture
+    def mock_domestic_broker(self) -> MagicMock:
+        """Create minimal mock domestic broker."""
+        broker = MagicMock()
+        return broker
+
+    @pytest.fixture
+    def mock_overseas_market(self) -> MagicMock:
+        """Create mock overseas market info."""
+        market = MagicMock()
+        market.name = "NASDAQ"
+        market.code = "US_NASDAQ"
+        market.exchange_code = "NASD"
+        market.is_domestic = False
+        return market
+
+    @pytest.fixture
+    def mock_brain_hold(self) -> MagicMock:
+        """Create mock brain that always holds."""
+        brain = MagicMock()
+        decision = MagicMock()
+        decision.action = "HOLD"
+        decision.confidence = 50
+        decision.rationale = "Testing balance parsing"
+        brain.decide = AsyncMock(return_value=decision)
+        return brain
+
+    @pytest.fixture
+    def mock_risk(self) -> MagicMock:
+        """Create mock risk manager."""
+        return MagicMock()
+
+    @pytest.fixture
+    def mock_db(self) -> MagicMock:
+        """Create mock database."""
+        return MagicMock()
+
+    @pytest.fixture
+    def mock_decision_logger(self) -> MagicMock:
+        """Create mock decision logger."""
+        return MagicMock()
+
+    @pytest.fixture
+    def mock_context_store(self) -> MagicMock:
+        """Create mock context store."""
+        store = MagicMock()
+        store.get_latest_timeframe = MagicMock(return_value=None)
+        return store
+
+    @pytest.fixture
+    def mock_criticality_assessor(self) -> MagicMock:
+        """Create mock criticality assessor."""
+        assessor = MagicMock()
+        assessor.assess_market_conditions = MagicMock(
+            return_value=MagicMock(value="NORMAL")
+        )
+        assessor.get_timeout = MagicMock(return_value=5.0)
+        return assessor
+
+    @pytest.fixture
+    def mock_telegram(self) -> MagicMock:
+        """Create mock telegram client."""
+        return MagicMock()
+
+    @pytest.mark.asyncio
+    async def test_overseas_balance_list_format(
+        self,
+        mock_domestic_broker: MagicMock,
+        mock_overseas_broker_with_list: MagicMock,
+        mock_brain_hold: MagicMock,
+        mock_risk: MagicMock,
+        mock_db: MagicMock,
+        mock_decision_logger: MagicMock,
+        mock_context_store: MagicMock,
+        mock_criticality_assessor: MagicMock,
+        mock_telegram: MagicMock,
+        mock_overseas_market: MagicMock,
+    ) -> None:
+        """Test overseas balance parsing with list format (output2=[{...}])."""
+        with patch("src.main.log_trade"):
+            # Should not raise KeyError
+            await trading_cycle(
+                broker=mock_domestic_broker,
+                overseas_broker=mock_overseas_broker_with_list,
+                brain=mock_brain_hold,
+                risk=mock_risk,
+                db_conn=mock_db,
+                decision_logger=mock_decision_logger,
+                context_store=mock_context_store,
+                criticality_assessor=mock_criticality_assessor,
+                telegram=mock_telegram,
+                market=mock_overseas_market,
+                stock_code="AAPL",
+            )
+
+        # Verify balance API was called
+        mock_overseas_broker_with_list.get_overseas_balance.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_overseas_balance_dict_format(
+        self,
+        mock_domestic_broker: MagicMock,
+        mock_overseas_broker_with_dict: MagicMock,
+        mock_brain_hold: MagicMock,
+        mock_risk: MagicMock,
+        mock_db: MagicMock,
+        mock_decision_logger: MagicMock,
+        mock_context_store: MagicMock,
+        mock_criticality_assessor: MagicMock,
+        mock_telegram: MagicMock,
+        mock_overseas_market: MagicMock,
+    ) -> None:
+        """Test overseas balance parsing with dict format (output2={...})."""
+        with patch("src.main.log_trade"):
+            # Should not raise KeyError
+            await trading_cycle(
+                broker=mock_domestic_broker,
+                overseas_broker=mock_overseas_broker_with_dict,
+                brain=mock_brain_hold,
+                risk=mock_risk,
+                db_conn=mock_db,
+                decision_logger=mock_decision_logger,
+                context_store=mock_context_store,
+                criticality_assessor=mock_criticality_assessor,
+                telegram=mock_telegram,
+                market=mock_overseas_market,
+                stock_code="AAPL",
+            )
+
+        # Verify balance API was called
+        mock_overseas_broker_with_dict.get_overseas_balance.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_overseas_balance_empty_format(
+        self,
+        mock_domestic_broker: MagicMock,
+        mock_overseas_broker_with_empty: MagicMock,
+        mock_brain_hold: MagicMock,
+        mock_risk: MagicMock,
+        mock_db: MagicMock,
+        mock_decision_logger: MagicMock,
+        mock_context_store: MagicMock,
+        mock_criticality_assessor: MagicMock,
+        mock_telegram: MagicMock,
+        mock_overseas_market: MagicMock,
+    ) -> None:
+        """Test overseas balance parsing with empty output2."""
+        with patch("src.main.log_trade"):
+            # Should not raise KeyError, should default to 0
+            await trading_cycle(
+                broker=mock_domestic_broker,
+                overseas_broker=mock_overseas_broker_with_empty,
+                brain=mock_brain_hold,
+                risk=mock_risk,
+                db_conn=mock_db,
+                decision_logger=mock_decision_logger,
+                context_store=mock_context_store,
+                criticality_assessor=mock_criticality_assessor,
+                telegram=mock_telegram,
+                market=mock_overseas_market,
+                stock_code="AAPL",
+            )
+
+        # Verify balance API was called
+        mock_overseas_broker_with_empty.get_overseas_balance.assert_called_once()