Fix retries in async mode (redis#2180)

* Avoid mutating a global retry_on_error list

* Make retries config consistent in sync and async

* Fix async retries

* Add new TestConnectionConstructorWithRetry tests

Author: elemoine

redis/asyncio/client.py

@@ -158,6 +158,7 @@ def __init__(
         encoding_errors: str = "strict",
         decode_responses: bool = False,
         retry_on_timeout: bool = False,
+        retry_on_error: Optional[list] = None,
         ssl: bool = False,
         ssl_keyfile: Optional[str] = None,
         ssl_certfile: Optional[str] = None,
@@ -176,8 +177,10 @@ def __init__(
     ):
         """
         Initialize a new Redis client.
-        To specify a retry policy, first set `retry_on_timeout` to `True`
-        then set `retry` to a valid `Retry` object
+        To specify a retry policy for specific errors, first set
+        `retry_on_error` to a list of the error/s to retry on, then set
+        `retry` to a valid `Retry` object.
+        To retry on TimeoutError, `retry_on_timeout` can also be set to `True`.
         """
         kwargs: Dict[str, Any]
         # auto_close_connection_pool only has an effect if connection_pool is
@@ -188,6 +191,10 @@ def __init__(
             auto_close_connection_pool if connection_pool is None else False
         )
         if not connection_pool:
+            if not retry_on_error:
+                retry_on_error = []
+            if retry_on_timeout is True:
+                retry_on_error.append(TimeoutError)
             kwargs = {
                 "db": db,
                 "username": username,
@@ -197,6 +204,7 @@ def __init__(
                 "encoding_errors": encoding_errors,
                 "decode_responses": decode_responses,
                 "retry_on_timeout": retry_on_timeout,
+                "retry_on_error": retry_on_error,
                 "retry": copy.deepcopy(retry),
                 "max_connections": max_connections,
                 "health_check_interval": health_check_interval,
@@ -461,7 +469,10 @@ async def _disconnect_raise(self, conn: Connection, error: Exception):
         is not a TimeoutError
         """
         await conn.disconnect()
-        if not (conn.retry_on_timeout and isinstance(error, TimeoutError)):
+        if (
+            conn.retry_on_error is None
+            or isinstance(error, tuple(conn.retry_on_error)) is False
+        ):
             raise error
 
     # COMMAND EXECUTION AND PROTOCOL PARSING

redis/asyncio/connection.py

@@ -578,6 +578,7 @@ class Connection:
         "socket_type",
         "redis_connect_func",
         "retry_on_timeout",
+        "retry_on_error",
         "health_check_interval",
         "next_health_check",
         "last_active_at",
@@ -606,6 +607,7 @@ def __init__(
         socket_keepalive_options: Optional[Mapping[int, Union[int, bytes]]] = None,
         socket_type: int = 0,
         retry_on_timeout: bool = False,
+        retry_on_error: Union[list, _Sentinel] = SENTINEL,
         encoding: str = "utf-8",
         encoding_errors: str = "strict",
         decode_responses: bool = False,
@@ -631,12 +633,19 @@ def __init__(
         self.socket_keepalive_options = socket_keepalive_options or {}
         self.socket_type = socket_type
         self.retry_on_timeout = retry_on_timeout
+        if retry_on_error is SENTINEL:
+            retry_on_error = []
         if retry_on_timeout:
+            retry_on_error.append(TimeoutError)
+        self.retry_on_error = retry_on_error
+        if retry_on_error:
             if not retry:
                 self.retry = Retry(NoBackoff(), 1)
             else:
                 # deep-copy the Retry object as it is mutable
                 self.retry = copy.deepcopy(retry)
+            # Update the retry's supported errors with the specified errors
+            self.retry.update_supported_errors(retry_on_error)
         else:
             self.retry = Retry(NoBackoff(), 0)
         self.health_check_interval = health_check_interval
@@ -1169,6 +1178,7 @@ def __init__(
         encoding_errors: str = "strict",
         decode_responses: bool = False,
         retry_on_timeout: bool = False,
+        retry_on_error: Union[list, _Sentinel] = SENTINEL,
         parser_class: Type[BaseParser] = DefaultParser,
         socket_read_size: int = 65536,
         health_check_interval: float = 0.0,
@@ -1190,12 +1200,19 @@ def __init__(
         self.socket_timeout = socket_timeout
         self.socket_connect_timeout = socket_connect_timeout or socket_timeout or None
         self.retry_on_timeout = retry_on_timeout
+        if retry_on_error is SENTINEL:
+            retry_on_error = []
         if retry_on_timeout:
+            retry_on_error.append(TimeoutError)
+        self.retry_on_error = retry_on_error
+        if retry_on_error:
             if retry is None:
                 self.retry = Retry(NoBackoff(), 1)
             else:
                 # deep-copy the Retry object as it is mutable
                 self.retry = copy.deepcopy(retry)
+            # Update the retry's supported errors with the specified errors
+            self.retry.update_supported_errors(retry_on_error)
         else:
             self.retry = Retry(NoBackoff(), 0)
         self.health_check_interval = health_check_interval

redis/asyncio/retry.py

@@ -35,6 +35,14 @@ def __init__(
         self._retries = retries
         self._supported_errors = supported_errors
 
+    def update_supported_errors(self, specified_errors: list):
+        """
+        Updates the supported errors with the specified error types
+        """
+        self._supported_errors = tuple(
+            set(self._supported_errors + tuple(specified_errors))
+        )
+
     async def call_with_retry(
         self, do: Callable[[], Awaitable[T]], fail: Callable[[RedisError], Any]
     ) -> T:

redis/client.py

@@ -914,7 +914,7 @@ def __init__(
         errors=None,
         decode_responses=False,
         retry_on_timeout=False,
-        retry_on_error=[],
+        retry_on_error=None,
         ssl=False,
         ssl_keyfile=None,
         ssl_certfile=None,
@@ -958,6 +958,8 @@ def __init__(
                     )
                 )
                 encoding_errors = errors
+            if not retry_on_error:
+                retry_on_error = []
             if retry_on_timeout is True:
                 retry_on_error.append(TimeoutError)
             kwargs = {

redis/connection.py

@@ -515,7 +515,7 @@ def __init__(
         socket_keepalive_options=None,
         socket_type=0,
         retry_on_timeout=False,
-        retry_on_error=[],
+        retry_on_error=SENTINEL,
         encoding="utf-8",
         encoding_errors="strict",
         decode_responses=False,
@@ -547,6 +547,8 @@ def __init__(
         self.socket_keepalive_options = socket_keepalive_options or {}
         self.socket_type = socket_type
         self.retry_on_timeout = retry_on_timeout
+        if retry_on_error is SENTINEL:
+            retry_on_error = []
         if retry_on_timeout:
             # Add TimeoutError to the errors list to retry on
             retry_on_error.append(TimeoutError)
@@ -1065,7 +1067,7 @@ def __init__(
         encoding_errors="strict",
         decode_responses=False,
         retry_on_timeout=False,
-        retry_on_error=[],
+        retry_on_error=SENTINEL,
         parser_class=DefaultParser,
         socket_read_size=65536,
         health_check_interval=0,
@@ -1088,6 +1090,8 @@ def __init__(
         self.password = password
         self.socket_timeout = socket_timeout
         self.retry_on_timeout = retry_on_timeout
+        if retry_on_error is SENTINEL:
+            retry_on_error = []
         if retry_on_timeout:
             # Add TimeoutError to the errors list to retry on
             retry_on_error.append(TimeoutError)

tests/test_asyncio/test_retry.py

@@ -3,7 +3,7 @@
 from redis.asyncio.connection import Connection, UnixDomainSocketConnection
 from redis.asyncio.retry import Retry
 from redis.backoff import AbstractBackoff, NoBackoff
-from redis.exceptions import ConnectionError
+from redis.exceptions import ConnectionError, TimeoutError
 
 
 class BackoffMock(AbstractBackoff):
@@ -22,23 +22,55 @@ def compute(self, failures):
 class TestConnectionConstructorWithRetry:
     "Test that the Connection constructors properly handles Retry objects"
 
+    @pytest.mark.parametrize("Class", [Connection, UnixDomainSocketConnection])
+    def test_retry_on_error_set(self, Class):
+        class CustomError(Exception):
+            pass
+
+        retry_on_error = [ConnectionError, TimeoutError, CustomError]
+        c = Class(retry_on_error=retry_on_error)
+        assert c.retry_on_error == retry_on_error
+        assert isinstance(c.retry, Retry)
+        assert c.retry._retries == 1
+        assert set(c.retry._supported_errors) == set(retry_on_error)
+
+    @pytest.mark.parametrize("Class", [Connection, UnixDomainSocketConnection])
+    def test_retry_on_error_not_set(self, Class):
+        c = Class()
+        assert c.retry_on_error == []
+        assert isinstance(c.retry, Retry)
+        assert c.retry._retries == 0
+
     @pytest.mark.parametrize("retry_on_timeout", [False, True])
     @pytest.mark.parametrize("Class", [Connection, UnixDomainSocketConnection])
-    def test_retry_on_timeout_boolean(self, Class, retry_on_timeout):
+    def test_retry_on_timeout(self, Class, retry_on_timeout):
         c = Class(retry_on_timeout=retry_on_timeout)
         assert c.retry_on_timeout == retry_on_timeout
         assert isinstance(c.retry, Retry)
         assert c.retry._retries == (1 if retry_on_timeout else 0)
 
     @pytest.mark.parametrize("retries", range(10))
     @pytest.mark.parametrize("Class", [Connection, UnixDomainSocketConnection])
-    def test_retry_on_timeout_retry(self, Class, retries: int):
+    def test_retry_with_retry_on_timeout(self, Class, retries: int):
         retry_on_timeout = retries > 0
         c = Class(retry_on_timeout=retry_on_timeout, retry=Retry(NoBackoff(), retries))
         assert c.retry_on_timeout == retry_on_timeout
         assert isinstance(c.retry, Retry)
         assert c.retry._retries == retries
 
+    @pytest.mark.parametrize("retries", range(10))
+    @pytest.mark.parametrize("Class", [Connection, UnixDomainSocketConnection])
+    def test_retry_with_retry_on_error(self, Class, retries: int):
+        class CustomError(Exception):
+            pass
+
+        retry_on_error = [ConnectionError, TimeoutError, CustomError]
+        c = Class(retry_on_error=retry_on_error, retry=Retry(NoBackoff(), retries))
+        assert c.retry_on_error == retry_on_error
+        assert isinstance(c.retry, Retry)
+        assert c.retry._retries == retries
+        assert set(c.retry._supported_errors) == set(retry_on_error)
+
 
 class TestRetry:
     "Test that Retry calls backoff and retries the expected number of times"