Fix provider fallback circuit on symbol-scoped errors

api/price_history_fallback.py

@@ -53,6 +53,15 @@ def __init__(
         self._polygon_circuit = polygon_circuit
         self._cmc_circuit = cmc_circuit
 
+    @staticmethod
+    def _is_provider_wide_failure(status_code: int) -> bool:
+        """Return true for errors that indicate a provider outage or global access problem."""
+        if status_code in (408, 429, 401, 403):
+            return True
+        if 500 <= status_code <= 599:
+            return True
+        return False
+
     def _polygon_http_get(
         self,
         url: str,
@@ -84,7 +93,7 @@ def _polygon_http_get(
                     self.logger.warning("Polygon HTTP %s%s; retry in %.1fs", response.status_code, label, wait_s)
                     time.sleep(wait_s)
                     continue
-                if self._polygon_circuit and response.status_code != 200:
+                if self._polygon_circuit and self._is_provider_wide_failure(response.status_code):
                     self._polygon_circuit.record_failure()
                 return response
             except requests.exceptions.Timeout:
@@ -136,7 +145,7 @@ def _cmc_http_get(
                     self.logger.warning("CMC HTTP %s%s; retry in %.1fs", response.status_code, label, wait_s)
                     time.sleep(wait_s)
                     continue
-                if self._cmc_circuit and response.status_code != 200:
+                if self._cmc_circuit and self._is_provider_wide_failure(response.status_code):
                     self._cmc_circuit.record_failure()
                 return response
             except requests.exceptions.Timeout:

tests/test_price_history_fallback_circuit.py

@@ -0,0 +1,79 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+
+from api.price_history_fallback import PriceHistoryFallbackClient
+from utils.provider_circuit import ProviderCallCircuit
+
+
+class _NoWaitGate:
+    def wait(self) -> None:
+        return None
+
+
+class _Session:
+    def __init__(self, status_codes: list[int]) -> None:
+        self.status_codes = list(status_codes)
+        self.calls = 0
+
+    def get(self, url: str, params: dict, timeout: float) -> SimpleNamespace:
+        del url, params, timeout
+        self.calls += 1
+        return SimpleNamespace(status_code=self.status_codes.pop(0))
+
+
+def test_polygon_symbol_scoped_4xx_does_not_open_provider_circuit() -> None:
+    circuit = ProviderCallCircuit("polygon", failure_threshold=2, recovery_timeout=60)
+    client = PriceHistoryFallbackClient(
+        polygon_api_key="poly-key",
+        polygon_rate_gate=_NoWaitGate(),
+        polygon_circuit=circuit,
+    )
+    client.polygon_session = _Session([404, 404, 200])
+
+    assert client._polygon_http_get("https://polygon.example/missing-a", {}, timeout=1, max_retries=1).status_code == 404
+    assert client._polygon_http_get("https://polygon.example/missing-b", {}, timeout=1, max_retries=1).status_code == 404
+
+    response = client._polygon_http_get("https://polygon.example/valid", {}, timeout=1, max_retries=1)
+
+    assert response is not None
+    assert response.status_code == 200
+    assert client.polygon_session.calls == 3
+    assert circuit.failures == 0
+
+
+def test_cmc_symbol_scoped_400_does_not_open_provider_circuit() -> None:
+    circuit = ProviderCallCircuit("cmc", failure_threshold=2, recovery_timeout=60)
+    client = PriceHistoryFallbackClient(
+        cmc_api_key="cmc-key",
+        cmc_rate_gate=_NoWaitGate(),
+        cmc_circuit=circuit,
+    )
+    client.cmc_session = _Session([400, 400, 200])
+
+    assert client._cmc_http_get("https://cmc.example/missing-a", {}, timeout=1, max_retries=1).status_code == 400
+    assert client._cmc_http_get("https://cmc.example/missing-b", {}, timeout=1, max_retries=1).status_code == 400
+
+    response = client._cmc_http_get("https://cmc.example/valid", {}, timeout=1, max_retries=1)
+
+    assert response is not None
+    assert response.status_code == 200
+    assert client.cmc_session.calls == 3
+    assert circuit.failures == 0
+
+
+def test_provider_wide_errors_still_open_circuit() -> None:
+    circuit = ProviderCallCircuit("polygon", failure_threshold=2, recovery_timeout=60)
+    client = PriceHistoryFallbackClient(
+        polygon_api_key="poly-key",
+        polygon_rate_gate=_NoWaitGate(),
+        polygon_circuit=circuit,
+    )
+    client.polygon_session = _Session([500, 500, 200])
+
+    assert client._polygon_http_get("https://polygon.example/a", {}, timeout=1, max_retries=1).status_code == 500
+    assert client._polygon_http_get("https://polygon.example/b", {}, timeout=1, max_retries=1).status_code == 500
+
+    assert client._polygon_http_get("https://polygon.example/skipped", {}, timeout=1, max_retries=1) is None
+    assert client.polygon_session.calls == 2
+    assert circuit.failures == 2