regular initializers for credentials (#1142)

* removes all dlt dependencies from logger

* uses dataclass_transform to generate init methods for configspec, warnings on inconsistent settings

* changes all configspecs to conform with new init methods, drops special init for credentials

* fixes setting native value None

Author: rudolfix

dlt/common/__init__.py

@@ -1,8 +1,8 @@
+from dlt.common import logger
 from dlt.common.arithmetics import Decimal
 from dlt.common.wei import Wei
 from dlt.common.pendulum import pendulum
 from dlt.common.json import json
 from dlt.common.runtime.signals import sleep
-from dlt.common.runtime import logger
 
 __all__ = ["Decimal", "Wei", "pendulum", "json", "sleep", "logger"]

dlt/common/configuration/resolve.py

@@ -76,7 +76,7 @@ def initialize_credentials(hint: Any, initial_value: Any) -> CredentialsConfigur
         first_credentials: CredentialsConfiguration = None
         for idx, spec in enumerate(specs_in_union):
             try:
-                credentials = spec(initial_value)
+                credentials = spec.from_init_value(initial_value)
                 if credentials.is_resolved():
                     return credentials
                 # keep first credentials in the union to return in case all of the match but not resolve
@@ -88,7 +88,7 @@ def initialize_credentials(hint: Any, initial_value: Any) -> CredentialsConfigur
         return first_credentials
     else:
         assert issubclass(hint, CredentialsConfiguration)
-        return hint(initial_value)  # type: ignore
+        return hint.from_init_value(initial_value)  # type: ignore
 
 
 def inject_section(

dlt/common/configuration/specs/api_credentials.py

@@ -6,9 +6,9 @@
 
 @configspec
 class OAuth2Credentials(CredentialsConfiguration):
-    client_id: str
-    client_secret: TSecretValue
-    refresh_token: Optional[TSecretValue]
+    client_id: str = None
+    client_secret: TSecretValue = None
+    refresh_token: Optional[TSecretValue] = None
     scopes: Optional[List[str]] = None
 
     token: Optional[TSecretValue] = None

dlt/common/configuration/specs/aws_credentials.py

@@ -121,3 +121,9 @@ def parse_native_representation(self, native_value: Any) -> None:
                 self.__is_resolved__ = True
         except Exception:
             raise InvalidBoto3Session(self.__class__, native_value)
+
+    @classmethod
+    def from_session(cls, botocore_session: Any) -> "AwsCredentials":
+        self = cls()
+        self.parse_native_representation(botocore_session)
+        return self

dlt/common/configuration/specs/base_configuration.py

@@ -2,6 +2,7 @@
 import inspect
 import contextlib
 import dataclasses
+import warnings
 
 from collections.abc import Mapping as C_Mapping
 from typing import (
@@ -19,7 +20,7 @@
     ClassVar,
     TypeVar,
 )
-from typing_extensions import get_args, get_origin
+from typing_extensions import get_args, get_origin, dataclass_transform
 from functools import wraps
 
 if TYPE_CHECKING:
@@ -44,6 +45,7 @@
 _F_BaseConfiguration: Any = type(object)
 _F_ContainerInjectableContext: Any = type(object)
 _T = TypeVar("_T", bound="BaseConfiguration")
+_C = TypeVar("_C", bound="CredentialsConfiguration")
 
 
 def is_base_configuration_inner_hint(inner_hint: Type[Any]) -> bool:
@@ -106,18 +108,26 @@ def is_secret_hint(hint: Type[Any]) -> bool:
 
 
 @overload
-def configspec(cls: Type[TAnyClass]) -> Type[TAnyClass]: ...
+def configspec(cls: Type[TAnyClass], init: bool = True) -> Type[TAnyClass]: ...
 
 
 @overload
-def configspec(cls: None = ...) -> Callable[[Type[TAnyClass]], Type[TAnyClass]]: ...
+def configspec(
+    cls: None = ..., init: bool = True
+) -> Callable[[Type[TAnyClass]], Type[TAnyClass]]: ...
 
 
+@dataclass_transform(eq_default=False, field_specifiers=(dataclasses.Field, dataclasses.field))
 def configspec(
-    cls: Optional[Type[Any]] = None,
+    cls: Optional[Type[Any]] = None, init: bool = True
 ) -> Union[Type[TAnyClass], Callable[[Type[TAnyClass]], Type[TAnyClass]]]:
     """Converts (via derivation) any decorated class to a Python dataclass that may be used as a spec to resolve configurations
 
+    __init__ method is synthesized by default. `init` flag is ignored if the decorated class implements custom __init__ as well as
+    when any of base classes has no synthesized __init__
+
+    All fields must have default values. This decorator will add `None` default values that miss one.
+
     In comparison the Python dataclass, a spec implements full dictionary interface for its attributes, allows instance creation from ie. strings
     or other types (parsing, deserialization) and control over configuration resolution process. See `BaseConfiguration` and CredentialsConfiguration` for
     more information.
@@ -142,6 +152,10 @@ def wrap(cls: Type[TAnyClass]) -> Type[TAnyClass]:
         # get all annotations without corresponding attributes and set them to None
         for ann in cls.__annotations__:
             if not hasattr(cls, ann) and not ann.startswith(("__", "_abc_")):
+                warnings.warn(
+                    f"Missing default value for field {ann} on {cls.__name__}. None assumed. All"
+                    " fields in configspec must have default."
+                )
                 setattr(cls, ann, None)
         # get all attributes without corresponding annotations
         for att_name, att_value in list(cls.__dict__.items()):
@@ -177,17 +191,18 @@ def default_factory(att_value=att_value):  # type: ignore[no-untyped-def]
 
         # We don't want to overwrite user's __init__ method
         # Create dataclass init only when not defined in the class
-        # (never put init on BaseConfiguration itself)
-        try:
-            is_base = cls is BaseConfiguration
-        except NameError:
-            is_base = True
-        init = False
-        base_params = getattr(cls, "__dataclass_params__", None)
-        if not is_base and (base_params and base_params.init or cls.__init__ is object.__init__):
-            init = True
+        # NOTE: any class without synthesized __init__ breaks the creation chain
+        has_default_init = super(cls, cls).__init__ == cls.__init__  # type: ignore[misc]
+        base_params = getattr(cls, "__dataclass_params__", None)  # cls.__init__ is object.__init__
+        synth_init = init and ((not base_params or base_params.init) and has_default_init)
+        if synth_init != init and has_default_init:
+            warnings.warn(
+                f"__init__ method will not be generated on {cls.__name__} because bas class didn't"
+                " synthesize __init__. Please correct `init` flag in confispec decorator. You are"
+                " probably receiving incorrect __init__ signature for type checking"
+            )
         # do not generate repr as it may contain secret values
-        return dataclasses.dataclass(cls, init=init, eq=False, repr=False)  # type: ignore
+        return dataclasses.dataclass(cls, init=synth_init, eq=False, repr=False)  # type: ignore
 
     # called with parenthesis
     if cls is None:
@@ -198,12 +213,14 @@ def default_factory(att_value=att_value):  # type: ignore[no-untyped-def]
 
 @configspec
 class BaseConfiguration(MutableMapping[str, Any]):
-    __is_resolved__: bool = dataclasses.field(default=False, init=False, repr=False)
+    __is_resolved__: bool = dataclasses.field(default=False, init=False, repr=False, compare=False)
     """True when all config fields were resolved and have a specified value type"""
-    __section__: str = dataclasses.field(default=None, init=False, repr=False)
-    """Obligatory section used by config providers when searching for keys, always present in the search path"""
-    __exception__: Exception = dataclasses.field(default=None, init=False, repr=False)
+    __exception__: Exception = dataclasses.field(
+        default=None, init=False, repr=False, compare=False
+    )
     """Holds the exception that prevented the full resolution"""
+    __section__: ClassVar[str] = None
+    """Obligatory section used by config providers when searching for keys, always present in the search path"""
     __config_gen_annotations__: ClassVar[List[str]] = []
     """Additional annotations for config generator, currently holds a list of fields of interest that have defaults"""
     __dataclass_fields__: ClassVar[Dict[str, TDtcField]]
@@ -342,9 +359,10 @@ def call_method_in_mro(config, method_name: str) -> None:
 class CredentialsConfiguration(BaseConfiguration):
     """Base class for all credentials. Credentials are configurations that may be stored only by providers supporting secrets."""
 
-    __section__: str = "credentials"
+    __section__: ClassVar[str] = "credentials"
 
-    def __init__(self, init_value: Any = None) -> None:
+    @classmethod
+    def from_init_value(cls: Type[_C], init_value: Any = None) -> _C:
         """Initializes credentials from `init_value`
 
         Init value may be a native representation of the credentials or a dict. In case of native representation (for example a connection string or JSON with service account credentials)
@@ -353,14 +371,10 @@ def __init__(self, init_value: Any = None) -> None:
 
         Credentials will be marked as resolved if all required fields are set.
         """
-        if init_value is None:
-            return
-        elif isinstance(init_value, C_Mapping):
-            self.update(init_value)
-        else:
-            self.parse_native_representation(init_value)
-        if not self.is_partial():
-            self.resolve()
+        # create an instance
+        self = cls()
+        self._apply_init_value(init_value)
+        return self
 
     def to_native_credentials(self) -> Any:
         """Returns native credentials object.
@@ -369,6 +383,16 @@ def to_native_credentials(self) -> Any:
         """
         return self.to_native_representation()
 
+    def _apply_init_value(self, init_value: Any = None) -> None:
+        if isinstance(init_value, C_Mapping):
+            self.update(init_value)
+        elif init_value is not None:
+            self.parse_native_representation(init_value)
+        else:
+            return
+        if not self.is_partial():
+            self.resolve()
+
     def __str__(self) -> str:
         """Get string representation of credentials to be displayed, with all secret parts removed"""
         return super().__str__()

dlt/common/configuration/specs/config_providers_context.py

@@ -1,4 +1,5 @@
 import contextlib
+import dataclasses
 import io
 from typing import ClassVar, List
 
@@ -28,7 +29,7 @@ class ConfigProvidersConfiguration(BaseConfiguration):
     only_toml_fragments: bool = True
 
     # always look in providers
-    __section__ = known_sections.PROVIDERS
+    __section__: ClassVar[str] = known_sections.PROVIDERS
 
 
 @configspec
@@ -37,8 +38,12 @@ class ConfigProvidersContext(ContainerInjectableContext):
 
     global_affinity: ClassVar[bool] = True
 
-    providers: List[ConfigProvider]
-    context_provider: ConfigProvider
+    providers: List[ConfigProvider] = dataclasses.field(
+        default=None, init=False, repr=False, compare=False
+    )
+    context_provider: ConfigProvider = dataclasses.field(
+        default=None, init=False, repr=False, compare=False
+    )
 
     def __init__(self) -> None:
         super().__init__()

dlt/common/configuration/specs/config_section_context.py

@@ -8,7 +8,7 @@
 class ConfigSectionContext(ContainerInjectableContext):
     TMergeFunc = Callable[["ConfigSectionContext", "ConfigSectionContext"], None]
 
-    pipeline_name: Optional[str]
+    pipeline_name: Optional[str] = None
     sections: Tuple[str, ...] = ()
     merge_style: TMergeFunc = None
     source_state_key: str = None
@@ -70,13 +70,3 @@ def __str__(self) -> str:
             super().__str__()
             + f": {self.pipeline_name} {self.sections}@{self.merge_style} state['{self.source_state_key}']"
         )
-
-    if TYPE_CHECKING:
-        # provide __init__ signature when type checking
-        def __init__(
-            self,
-            pipeline_name: str = None,
-            sections: Tuple[str, ...] = (),
-            merge_style: TMergeFunc = None,
-            source_state_key: str = None,
-        ) -> None: ...

dlt/common/configuration/specs/connection_string_credentials.py

@@ -1,14 +1,15 @@
-from typing import Any, ClassVar, Dict, List, Optional
+import dataclasses
+from typing import Any, ClassVar, Dict, List, Optional, Union
+
 from dlt.common.libs.sql_alchemy import URL, make_url
 from dlt.common.configuration.specs.exceptions import InvalidConnectionString
-
 from dlt.common.typing import TSecretValue
 from dlt.common.configuration.specs.base_configuration import CredentialsConfiguration, configspec
 
 
 @configspec
 class ConnectionStringCredentials(CredentialsConfiguration):
-    drivername: str = None
+    drivername: str = dataclasses.field(default=None, init=False, repr=False, compare=False)
     database: str = None
     password: Optional[TSecretValue] = None
     username: str = None
@@ -18,6 +19,11 @@ class ConnectionStringCredentials(CredentialsConfiguration):
 
     __config_gen_annotations__: ClassVar[List[str]] = ["port", "password", "host"]
 
+    def __init__(self, connection_string: Union[str, Dict[str, Any]] = None) -> None:
+        """Initializes the credentials from SQLAlchemy like connection string or from dict holding connection string elements"""
+        super().__init__()
+        self._apply_init_value(connection_string)
+
     def parse_native_representation(self, native_value: Any) -> None:
         if not isinstance(native_value, str):
             raise InvalidConnectionString(self.__class__, native_value, self.drivername)

dlt/common/configuration/specs/gcp_credentials.py

@@ -1,5 +1,6 @@
+import dataclasses
 import sys
-from typing import Any, Final, List, Tuple, Union, Dict
+from typing import Any, ClassVar, Final, List, Tuple, Union, Dict
 
 from dlt.common import json, pendulum
 from dlt.common.configuration.specs.api_credentials import OAuth2Credentials
@@ -22,8 +23,12 @@
 
 @configspec
 class GcpCredentials(CredentialsConfiguration):
-    token_uri: Final[str] = "https://oauth2.googleapis.com/token"
-    auth_uri: Final[str] = "https://accounts.google.com/o/oauth2/auth"
+    token_uri: Final[str] = dataclasses.field(
+        default="https://oauth2.googleapis.com/token", init=False, repr=False, compare=False
+    )
+    auth_uri: Final[str] = dataclasses.field(
+        default="https://accounts.google.com/o/oauth2/auth", init=False, repr=False, compare=False
+    )
 
     project_id: str = None
 
@@ -69,7 +74,9 @@ def to_gcs_credentials(self) -> Dict[str, Any]:
 class GcpServiceAccountCredentialsWithoutDefaults(GcpCredentials):
     private_key: TSecretValue = None
     client_email: str = None
-    type: Final[str] = "service_account"  # noqa: A003
+    type: Final[str] = dataclasses.field(  # noqa: A003
+        default="service_account", init=False, repr=False, compare=False
+    )
 
     def parse_native_representation(self, native_value: Any) -> None:
         """Accepts ServiceAccountCredentials as native value. In other case reverts to serialized services.json"""
@@ -121,8 +128,10 @@ def __str__(self) -> str:
 @configspec
 class GcpOAuthCredentialsWithoutDefaults(GcpCredentials, OAuth2Credentials):
     # only desktop app supported
-    refresh_token: TSecretValue
-    client_type: Final[str] = "installed"
+    refresh_token: TSecretValue = None
+    client_type: Final[str] = dataclasses.field(
+        default="installed", init=False, repr=False, compare=False
+    )
 
     def parse_native_representation(self, native_value: Any) -> None:
         """Accepts Google OAuth2 credentials as native value. In other case reverts to serialized oauth client secret json"""
@@ -237,7 +246,7 @@ def __str__(self) -> str:
 
 @configspec
 class GcpDefaultCredentials(CredentialsWithDefault, GcpCredentials):
-    _LAST_FAILED_DEFAULT: float = 0.0
+    _LAST_FAILED_DEFAULT: ClassVar[float] = 0.0
 
     def parse_native_representation(self, native_value: Any) -> None:
         """Accepts google credentials as native value"""

dlt/common/configuration/specs/known_sections.py

@@ -13,6 +13,9 @@
 EXTRACT = "extract"
 """extract stage of the pipeline"""
 
+SCHEMA = "schema"
+"""schema configuration, ie. normalizers"""
+
 PROVIDERS = "providers"
 """secrets and config providers"""