skip ssl import if not available (redis#3078)

* skip `ssl` import if not available

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

* address review feedback and fix lint errors

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

* remove TYPE_CHECKING clause from ssl conditional

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

---------

Signed-off-by: Joel Dice <joel.dice@fermyon.com>
Co-authored-by: petyaslavova <petya.slavova@redis.com>

Author: dicej

redis/asyncio/client.py

@@ -2,7 +2,6 @@
 import copy
 import inspect
 import re
-import ssl
 import warnings
 from typing import (
     TYPE_CHECKING,
@@ -72,6 +71,7 @@
 from redis.typing import ChannelT, EncodableT, KeyT
 from redis.utils import (
     HIREDIS_AVAILABLE,
+    SSL_AVAILABLE,
     _set_info_logger,
     deprecated_function,
     get_lib_version,
@@ -80,6 +80,11 @@
     truncate_command_for_exception,
 )
 
+if TYPE_CHECKING and SSL_AVAILABLE:
+    from ssl import TLSVersion
+else:
+    TLSVersion = None
+
 PubSubHandler = Callable[[Dict[str, str]], Awaitable[None]]
 _KeyT = TypeVar("_KeyT", bound=KeyT)
 _ArgT = TypeVar("_ArgT", KeyT, EncodableT)
@@ -227,7 +232,7 @@ def __init__(
         ssl_ca_certs: Optional[str] = None,
         ssl_ca_data: Optional[str] = None,
         ssl_check_hostname: bool = False,
-        ssl_min_version: Optional[ssl.TLSVersion] = None,
+        ssl_min_version: Optional[TLSVersion] = None,
         ssl_ciphers: Optional[str] = None,
         max_connections: Optional[int] = None,
         single_connection_client: bool = False,

redis/asyncio/cluster.py

@@ -2,7 +2,6 @@
 import collections
 import random
 import socket
-import ssl
 import warnings
 from typing import (
     Any,
@@ -64,7 +63,19 @@
     TryAgainError,
 )
 from redis.typing import AnyKeyT, EncodableT, KeyT
-from redis.utils import deprecated_function, get_lib_version, safe_str, str_if_bytes, truncate_command_for_exception
+from redis.utils import (
+    SSL_AVAILABLE,
+    deprecated_function,
+    get_lib_version,
+    safe_str,
+    str_if_bytes,
+    truncate_command_for_exception,
+)
+
+if SSL_AVAILABLE:
+    from ssl import TLSVersion
+else:
+    TLSVersion = None
 
 TargetNodesT = TypeVar(
     "TargetNodesT", str, "ClusterNode", List["ClusterNode"], Dict[Any, "ClusterNode"]
@@ -247,7 +258,7 @@ def __init__(
         ssl_certfile: Optional[str] = None,
         ssl_check_hostname: bool = False,
         ssl_keyfile: Optional[str] = None,
-        ssl_min_version: Optional[ssl.TLSVersion] = None,
+        ssl_min_version: Optional[TLSVersion] = None,
         ssl_ciphers: Optional[str] = None,
         protocol: Optional[int] = 2,
         address_remap: Optional[Callable[[Tuple[str, int]], Tuple[str, int]]] = None,
@@ -1161,9 +1172,7 @@ def get_node(
             return self.nodes_cache.get(node_name)
         else:
             raise DataError(
-                "get_node requires one of the following: "
-                "1. node name "
-                "2. host and port"
+                "get_node requires one of the following: 1. node name 2. host and port"
             )
 
     def set_nodes(
@@ -1345,7 +1354,7 @@ async def initialize(self) -> None:
                             if len(disagreements) > 5:
                                 raise RedisClusterException(
                                     f"startup_nodes could not agree on a valid "
-                                    f'slots cache: {", ".join(disagreements)}'
+                                    f"slots cache: {', '.join(disagreements)}"
                                 )
 
             # Validate if all slots are covered or if we should try next startup node

redis/asyncio/connection.py

@@ -3,7 +3,6 @@
 import enum
 import inspect
 import socket
-import ssl
 import sys
 import warnings
 import weakref
@@ -27,6 +26,16 @@
 )
 from urllib.parse import ParseResult, parse_qs, unquote, urlparse
 
+from ..utils import SSL_AVAILABLE
+
+if SSL_AVAILABLE:
+    import ssl
+    from ssl import SSLContext, TLSVersion
+else:
+    ssl = None
+    TLSVersion = None
+    SSLContext = None
+
 from ..auth.token import TokenInterface
 from ..event import AsyncAfterConnectionReleasedEvent, EventDispatcher
 from ..utils import deprecated_args, format_error_message
@@ -763,10 +772,13 @@ def __init__(
         ssl_ca_certs: Optional[str] = None,
         ssl_ca_data: Optional[str] = None,
         ssl_check_hostname: bool = False,
-        ssl_min_version: Optional[ssl.TLSVersion] = None,
+        ssl_min_version: Optional[TLSVersion] = None,
         ssl_ciphers: Optional[str] = None,
         **kwargs,
     ):
+        if not SSL_AVAILABLE:
+            raise RedisError("Python wasn't built with SSL support")
+
         self.ssl_context: RedisSSLContext = RedisSSLContext(
             keyfile=ssl_keyfile,
             certfile=ssl_certfile,
@@ -834,9 +846,12 @@ def __init__(
         ca_certs: Optional[str] = None,
         ca_data: Optional[str] = None,
         check_hostname: bool = False,
-        min_version: Optional[ssl.TLSVersion] = None,
+        min_version: Optional[TLSVersion] = None,
         ciphers: Optional[str] = None,
     ):
+        if not SSL_AVAILABLE:
+            raise RedisError("Python wasn't built with SSL support")
+
         self.keyfile = keyfile
         self.certfile = certfile
         if cert_reqs is None:
@@ -857,9 +872,9 @@ def __init__(
         self.check_hostname = check_hostname
         self.min_version = min_version
         self.ciphers = ciphers
-        self.context: Optional[ssl.SSLContext] = None
+        self.context: Optional[SSLContext] = None
 
-    def get(self) -> ssl.SSLContext:
+    def get(self) -> SSLContext:
         if not self.context:
             context = ssl.create_default_context()
             context.check_hostname = self.check_hostname

redis/connection.py

@@ -1,7 +1,6 @@
 import copy
 import os
 import socket
-import ssl
 import sys
 import threading
 import time
@@ -49,6 +48,11 @@
     str_if_bytes,
 )
 
+if SSL_AVAILABLE:
+    import ssl
+else:
+    ssl = None
+
 if HIREDIS_AVAILABLE:
     import hiredis