common.configuration.specs.base_configuration

configspec

def configspec(
    cls: Optional[Type[Any]] = None
) -> Union[Type[TAnyClass], Callable[[Type[TAnyClass]], Type[TAnyClass]]]

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Converts (via derivation) any decorated class to a Python dataclass that may be used as a spec to resolve configurations

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.

BaseConfiguration Objects

@configspec
class BaseConfiguration(MutableMapping[str, Any])

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__is_resolved__

True when all config fields were resolved and have a specified value type

__section__

Obligatory section used by config providers when searching for keys, always present in the search path

__exception__

Holds the exception that prevented the full resolution

__config_gen_annotations__

Additional annotations for config generator, currently holds a list of fields of interest that have defaults

__dataclass_fields__

Typing for dataclass fields

parse_native_representation

def parse_native_representation(native_value: Any) -> None

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Initialize the configuration fields by parsing the native_value which should be a native representation of the configuration or credentials, for example database connection string or JSON serialized GCP service credentials file.

Arguments:

• native_value Any - A native representation of the configuration

Raises:

• NotImplementedError - This configuration does not have a native representation
• ValueError - The value provided cannot be parsed as native representation

to_native_representation

def to_native_representation() -> Any

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Represents the configuration instance in its native form ie. database connection string or JSON serialized GCP service credentials file.

Raises:

• NotImplementedError - This configuration does not have a native representation

Returns:

• Any - A native representation of the configuration

get_resolvable_fields

@classmethod
def get_resolvable_fields(cls) -> Dict[str, type]

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Returns a mapping of fields to their type hints. Dunders should not be resolved and are not returned

is_partial

def is_partial() -> bool

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Returns True when any required resolvable field has its value missing.

copy

def copy() -> _T

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Returns a deep copy of the configuration instance

__iter__

def __iter__() -> Iterator[str]

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Iterator or valid key names

CredentialsConfiguration Objects

@configspec
class CredentialsConfiguration(BaseConfiguration)

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Base class for all credentials. Credentials are configurations that may be stored only by providers supporting secrets.

__init__

def __init__(init_value: Any = None) -> None

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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) a parse_native_representation method will be used to parse it. In case of a dict, the credentials object will be updated with key: values of the dict. Unexpected values in the dict will be ignored.

Credentials will be marked as resolved if all required fields are set.

to_native_credentials

def to_native_credentials() -> Any

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Returns native credentials object.

By default calls to_native_representation method.

__str__

def __str__() -> str

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Get string representation of credentials to be displayed, with all secret parts removed

CredentialsWithDefault Objects

class CredentialsWithDefault()

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A mixin for credentials that can be instantiated from default ie. from well known env variable with credentials

ContainerInjectableContext Objects

@configspec
class ContainerInjectableContext(BaseConfiguration)

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Base class for all configurations that may be injected from a Container. Injectable configuration is called a context

can_create_default

If True, Container is allowed to create default context instance, if none exists

global_affinity

If True, Container will create context that will be visible in any thread. If False, per thread context is created

add_extras

def add_extras() -> None

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Called right after context was added to the container. Benefits mostly the config provider injection context which adds extra providers using the initial ones.