Remove sdk_config_customizer

README.md

@@ -214,7 +214,6 @@ config = (
 | `timeouts` | `TimeoutConfig` | discovery 5s, connect 5s, read 30s | Discovery and SDK per-attempt timeouts |
 | `aws_region` | `str` | `"us-east-1"` | Region placeholder required by the SDK |
 | `user_agent` | str, callable, or `None` | `alternator-client-python/<version>` | Final User-Agent; `None` omits the wire header |
-| `sdk_config_customizer` | callable | `None` | Callback for safe SDK config kwargs adjustments |
 | `active_refresh_interval_ms` | `int` | `1000` | Node refresh interval when active |
 | `idle_refresh_interval_ms` | `int` | `60000` | Node refresh interval when idle |
 
@@ -779,9 +778,13 @@ client = create_client(config)
 ```
 
 The client still owns the SDK config object, endpoint routing, and the final
-wire `User-Agent` header. Python botocore does not expose direct knobs for max
-idle connections, max idle connections per host, or idle connection timeout;
-tune `max_pool_connections`, retries, and timeouts instead.
+wire `User-Agent` header. Use typed Alternator config fields for SDK transport
+settings: `RetryConfig` for retry behavior, `TimeoutConfig` for connect/read
+timeouts, `max_pool_connections` for pool sizing, `aws_region` for the SDK
+region placeholder, and `TLS` for client certificates. Python botocore does not
+expose direct knobs for max idle connections, max idle connections per host, or
+idle connection timeout; tune `max_pool_connections`, retries, and timeouts
+instead.
 
 ## Production Recommendations
 

alternator/__init__.py

@@ -106,7 +106,6 @@
     ResponseCompression,
     RetryConfig,
     RetryMode,
-    SDKConfigCustomizer,
     TimeoutConfig,
     TlsConfig,
     TlsSessionCacheConfig,
@@ -160,7 +159,6 @@
     "NodeListPollingConfig",
     "RetryConfig",
     "RetryMode",
-    "SDKConfigCustomizer",
     "TimeoutConfig",
     "TlsConfig",
     "TlsSessionCacheConfig",

alternator/config.py

@@ -17,7 +17,6 @@
 
 logger = logging.getLogger("alternator")
 
-SDKConfigCustomizer = Callable[[dict[str, Any]], None]
 SDKClientCert = str | tuple[str, str]
 UserAgentCustomizer = Callable[[str], str]
 UserAgent = str | UserAgentCustomizer
@@ -403,7 +402,6 @@ class Config:
     # SDK settings
     aws_region: str = "us-east-1"
     user_agent: UserAgent | None = DEFAULT_USER_AGENT
-    sdk_config_customizer: SDKConfigCustomizer | None = None
 
     def __post_init__(self) -> None:
         """Validate configuration values."""
@@ -473,7 +471,6 @@ def __init__(self) -> None:
         self._timeouts = TimeoutConfig()
         self._aws_region = "us-east-1"
         self._user_agent: UserAgent | None = DEFAULT_USER_AGENT
-        self._sdk_config_customizer: SDKConfigCustomizer | None = None
 
     def with_seeds(self, *hosts: str) -> AlternatorConfigBuilder:
         """Add seed hosts for node discovery."""
@@ -628,14 +625,6 @@ def with_user_agent(
         self._user_agent = user_agent
         return self
 
-    def with_sdk_config_customizer(
-        self,
-        customizer: SDKConfigCustomizer | None,
-    ) -> AlternatorConfigBuilder:
-        """Set a callback that can adjust generated SDK config kwargs."""
-        self._sdk_config_customizer = customizer
-        return self
-
     def build(self) -> Config:
         """Build the configuration object."""
         from alternator.core.routing_scope import ClusterScope
@@ -656,7 +645,6 @@ def build(self) -> Config:
             timeouts=self._timeouts,
             aws_region=self._aws_region,
             user_agent=self._user_agent,
-            sdk_config_customizer=self._sdk_config_customizer,
         )
 
 
@@ -673,8 +661,6 @@ def build_sdk_config_kwargs(config: Config) -> dict[str, Any]:
     }
     if config.scheme == "https" and config.tls.sdk_client_cert is not None:
         kwargs["client_cert"] = config.tls.sdk_client_cert
-    if config.sdk_config_customizer is not None:
-        config.sdk_config_customizer(kwargs)
     if config.user_agent is not None:
         kwargs["user_agent"] = _resolve_user_agent(config.user_agent)
     else:

docs/CAPABILITY_MATRIX.md

@@ -20,7 +20,7 @@ and intentionally deferred behavior.
 | TLS server trust | Supported | Existing API | System CA, custom CA, hostname verification, and trust-all mode exist. |
 | TLS client certificates | Supported | [#38](https://github.com/scylladb/alternator-client-python/issues/38) | mTLS certificate/key paths are loaded into discovery SSL contexts and SDK `client_cert` config. |
 | TLS key log file | Supported | [#38](https://github.com/scylladb/alternator-client-python/issues/38) | Debug-only key log file paths are applied to SSL contexts when supported by the runtime. |
-| Transport and SDK config knobs | Supported | [#34](https://github.com/scylladb/alternator-client-python/issues/34) | Retry, pool, connect/read timeout, region, and SDK config customizer settings are wired into sync and async SDK clients. |
+| Transport and SDK config knobs | Supported | [#34](https://github.com/scylladb/alternator-client-python/issues/34), [#89](https://github.com/scylladb/alternator-client-python/issues/89) | Retry, pool, connect/read timeout, region, TLS client certificates, and User-Agent settings have typed Alternator config fields. The client does not expose raw SDK config mutation. |
 | Key route affinity | Supported | [#23](https://github.com/scylladb/alternator-client-python/issues/23) | RMW detection, single-write affinity, and BatchWriteItem preferred-node voting are implemented with fallback on missing or ambiguous routing data. |
 | Helper lifecycle facade | Supported | [#33](https://github.com/scylladb/alternator-client-python/issues/33) | `Helper` and `AsyncHelper` expose lifecycle, node inspection, topology checks, and partition-key diagnostics. |
 | Compatibility and release decisions | Supported | [#39](https://github.com/scylladb/alternator-client-python/issues/39) | Decision record lives in [docs/COMPATIBILITY_AND_RELEASE.md](COMPATIBILITY_AND_RELEASE.md). |

docs/RELEASE_NOTES.md

@@ -15,7 +15,8 @@ authority for compatibility decisions.
   `without_fallback(...)`.
 - Added topology validation helpers for configured datacenter/rack scopes.
 - Added transport configuration for SDK retries, connect/read timeouts,
-  connection pool size, region placeholder, and SDK config customization.
+  connection pool size, region placeholder, TLS client certificates, and
+  User-Agent customization.
 - Added Alternator-specific `User-Agent` control with `Config.user_agent`.
   By default, requests send the Alternator Python client identity; callers can
   pass `None` to remove the wire header, a string to set a final value, or a
@@ -51,8 +52,9 @@ authority for compatibility decisions.
   For `BatchWriteItem`, valid put/delete entries vote for their preferred node.
   Tied votes, missing partition-key metadata, unsupported key values, no active
   nodes, or no eligible votes fall back to normal routing.
-- `sdk_config_customizer` can adjust supported SDK config kwargs, but the client
-  still owns endpoint routing and reapplies auth-managed signature settings.
+- The client owns the SDK config object, endpoint routing, auth-managed
+  signature settings, TLS client certificate settings, retries, timeouts, and
+  final wire `User-Agent` handling.
 - TLS key logs contain traffic decryption material and should only be used in
   protected debugging environments.
 

tests/unit/test_boto_config.py

@@ -142,61 +142,6 @@ def test_user_agent_string_must_be_non_empty(self) -> None:
         with pytest.raises(ValueError, match="user_agent"):
             _create_boto_config(config, auth_enabled=False)
 
-    def test_sdk_config_customizer_can_adjust_safe_fields(self) -> None:
-        """SDK config customizer can adjust generated config kwargs."""
-
-        def customize(kwargs: dict[str, object]) -> None:
-            kwargs["connect_timeout"] = 9.0
-
-        config = self._make_config(sdk_config_customizer=customize)
-        boto_config = _create_boto_config(config, auth_enabled=False)
-
-        assert boto_config.connect_timeout == 9.0
-        assert boto_config.user_agent == DEFAULT_USER_AGENT
-
-    def test_user_agent_none_overrides_sdk_config_customizer(self) -> None:
-        """The typed user-agent API removes generic customizer user-agent output."""
-
-        def customize(kwargs: dict[str, object]) -> None:
-            kwargs["user_agent"] = "legacy-customizer/1.0"
-
-        config = self._make_config(
-            sdk_config_customizer=customize,
-            user_agent=None,
-        )
-        boto_config = _create_boto_config(config, auth_enabled=False)
-
-        assert boto_config.user_agent is None
-        assert "user_agent" not in boto_config._user_provided_options
-
-    def test_user_agent_callback_overrides_sdk_config_customizer(self) -> None:
-        """The typed user-agent API wins over the generic SDK customizer."""
-
-        def customize(kwargs: dict[str, object]) -> None:
-            kwargs["user_agent"] = "legacy-customizer/1.0"
-
-        config = self._make_config(
-            sdk_config_customizer=customize,
-            user_agent=lambda default: f"orders-service {default}",
-        )
-        boto_config = _create_boto_config(config, auth_enabled=False)
-
-        assert boto_config.user_agent == f"orders-service {DEFAULT_USER_AGENT}"
-
-    def test_sdk_config_customizer_cannot_override_signature(self) -> None:
-        """Auth-managed signature settings override customizer changes."""
-
-        def customize(kwargs: dict[str, object]) -> None:
-            kwargs["signature_version"] = "v4"
-
-        config = self._make_config(sdk_config_customizer=customize)
-
-        unsigned_config = _create_boto_config(config, auth_enabled=False)
-        signed_config = _create_boto_config(config, auth_enabled=True)
-
-        assert unsigned_config.signature_version is UNSIGNED
-        assert "signature_version" not in signed_config._user_provided_options
-
     def test_client_cert_propagated_for_https(self) -> None:
         """TLS client certificate settings flow into BotoConfig."""
         config = self._make_config(

tests/unit/test_config.py

@@ -94,7 +94,6 @@ def test_default_values(self) -> None:
         assert config.node_list_polling.idle_interval_ms == 60000
         assert config.aws_region == "us-east-1"
         assert config.user_agent.startswith("alternator-client-python/")
-        assert config.sdk_config_customizer is None
         assert isinstance(config.routing_scope, ClusterScope)
 
 
@@ -437,21 +436,6 @@ def test_build_with_user_agent_none(self) -> None:
         )
         assert config.user_agent is None
 
-    def test_build_with_sdk_config_customizer(self) -> None:
-        """Test building config with SDK config customizer."""
-
-        def customize(kwargs: dict[str, object]) -> None:
-            kwargs["user_agent"] = "test"
-
-        config = (
-            AlternatorConfigBuilder()
-            .with_seeds("localhost")
-            .with_port(8000)
-            .with_sdk_config_customizer(customize)
-            .build()
-        )
-        assert config.sdk_config_customizer is customize
-
 
 class TestTlsConfig:
     """Tests for TLS factory methods."""