kiarina-utils-common

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[!NOTE] What is this? A package providing lightweight configuration resolution, dynamic imports, and registry foundations.

Dependencies

Installation

pip install kiarina-utils-common

Features

• Implementing a Plugin System Build a plugin system that selects and dynamically creates implementations from configured import paths.
• Managing a Singleton Retain and reuse an object created from resolved configuration.

Implementing a Plugin System

ComponentRegistry can be used to build a plugin system that selects and creates implementations from configured import paths. The following example uses pydantic-settings-manager.

sample/
  hoge/
    _instances/
      hoge_registry.py
    _services/
      base_hoge.py
    _types/
      hoge.py
      hoge_name.py
      hoge_alias.py
      hoge_specifier.py
    __init__.py
    _settings.py
  hoge_impl/
    vanilla/
      _helpers/
        create_vanilla_hoge.py
      _services/
        vanilla_hoge.py
      __init__.py
      _settings.py

Define the abstraction:

# sample/hoge/_types/hoge_name.py
HogeName: TypeAlias = str

# sample/hoge/_types/hoge_alias.py
HogeAlias: TypeAlias = str

# sample/hoge/_types/hoge_specifier.py
HogeSpecifier: TypeAlias = str
"""{HogeName}[?{ConfigString}]"""

# sample/hoge/_types/hoge.py
@runtime_checkable
class Hoge(Protocol):
    name: HogeName
    def hello(self) -> None: ...

# sample/hoge/_services/base_hoge.py
class BaseHoge(Hoge):
    def __init__(self) -> None:
        self._name: HogeName | None = None

    @property
    def name(self) -> HogeName:
        if self._name is None:
            raise ValueError("name is not set")
        return self._name

    @name.setter
    def name(self, value: HogeName) -> None:
        self._name = value

# sample/hoge/_settings.py
class HogeSettings(BaseSettings):
    model_config = SettingsConfigDict(
        env_prefix="SAMPLE_HOGE_",
        extra="ignore",
    )

    default: HogeSpecifier = "vanilla"

    aliases: dict[HogeAlias, HogeName] = Field(default_factory=dict)

    presets: dict[HogeName, ImportPath] = Field(
        default_factory=lambda: {
            "vanilla": "sample.hoge_impl.vanilla:create_vanilla_hoge",
        }
    )

    customs: dict[HogeName, ImportPath] = Field(default_factory=dict)

settings_manager = SettingsManager(HogeSettings)

# sample/hoge/_instances/hoge_registry.py
def _factory_wrapper(
    factory: ComponentFactory[Hoge],
    component_name: str,
    *args: Any,
    **kwargs: Any,
) -> Hoge:
    instance = factory(*args, **kwargs)
    instance.name = component_name
    return instance

hoge_registry = ComponentRegistry[Hoge](
    expected_type=cast(type[Hoge], Hoge),
    component_label="Hoge",
    get_default=lambda: settings_manager.settings.default,
    get_aliases=lambda: settings_manager.settings.aliases,
    get_presets=lambda: settings_manager.settings.presets,
    get_customs=lambda: settings_manager.settings.customs,
    factory_wrapper=_factory_wrapper,
)

# sample/hoge/__init__.py
__all__ = [
    "BaseHoge",
    "Hoge",
    "HogeName",
    "HogeAlias",
    "HogeSpecifier",
    "settings_manager",
    "hoge_registry",
]

Define the implementation:

# sample/hoge_impl/vanilla/_settings.py
class VanillaHogeSettings(BaseSettings):
    model_config = SettingsConfigDict(
        env_prefix="SAMPLE_HOGE_VANILLA_",
        extra="ignore",
    )
    message: str = "Hello from VanillaHoge!"

settings_manager = SettingsManager(VanillaHogeSettings)

# sample/hoge_impl/vanilla/_services/vanilla_hoge.py
class VanillaHoge(BaseHoge):
    def __init__(self, settings: VanillaHogeSettings) -> None:
        super().__init__()
        self.settings: VanillaHogeSettings = settings

    def hello(self) -> None:
        print(self.settings.message)

# sample/hoge_impl/vanilla/_helpers/create_vanilla_hoge.py
def create_vanilla_hoge(**kwargs: Any) -> VanillaHoge:
    settings = settings_manager.get_settings()

    if kwargs:
        settings = VanillaHogeSettings.model_validate(
            {**settings.model_dump(), **kwargs}
        )

    return VanillaHoge(settings)

# sample/hoge_impl/vanilla/__init__.py
__all__ = ["create_vanilla_hoge", "VanillaHoge", "settings_manager"]

Usage:

hoge = hoge_registry.resolve()  # Get the default
hoge = hoge_registry.resolve("vanilla")  # Get a preset
hoge = hoge_registry.resolve("vanilla?message=Bye")  # Override with ConfigString
hoge.hello()

Managing a Singleton

ObjectRegistry can retain and reuse an object created from resolved configuration.

Define the registry:

from typing import Any

from kiarina.utils.object_registry import ObjectRegistry
from rich.console import Console


def _factory(name: str, config: dict[str, Any]) -> Console:
    return Console(**config)


console_registry = ObjectRegistry[Console, dict[str, Any]](
    expected_type=Console,
    object_label="Console",
    get_default=lambda: "default",
    get_presets=lambda: {
        "default": {"stderr": True, "highlight": False},
    },
    factory=_factory,
)

Usage:

console1 = console_registry.get()  # Get the default
console2 = console_registry.get("default")  # Get a preset
console3 = console_registry.resolve("default?highlight=True")  # Override with ConfigString

console1.print("Hello, World!")
assert console1 is console_registry.get()  # Return the same object

API Reference

kiarina.utils.common

from kiarina.utils.common import (
    ConfigString,
    ImportPath,
    download_file,
    import_object,
    parse_config_string,
)

download_file

def download_file(
    url: str,
    sha256: str,
    cache_path: os.PathLike[str] | str,
) -> Path: ...

Download a file to cache_path if it does not already exist.

The file is first written to a temporary file in the same directory, verified with SHA-256, and then atomically placed at cache_path. Existing files are reused without hash verification.

• RuntimeError: Downloading fails or the SHA-256 digest does not match

import_object

def import_object(import_path: ImportPath) -> Any: ...

Import and return an object from an import path in module_name:object_name format.

• ValueError: The import path format is invalid
• ImportError: The module cannot be imported
• AttributeError: The object does not exist in the module

parse_config_string

def parse_config_string(
    config_str: ConfigString,
    *,
    separator: str = "&",
    key_value_separator: str = "=",
    nested_separator: str = ".",
    brackets: str = "()",
) -> dict[str, Any]: ...

Convert a configuration string into a nested dictionary.

Values are automatically converted to bool, int, or float. Keys without values become None, and numeric nested keys are treated as list indices. Values enclosed by brackets may contain separator characters and are not type-converted.

parse_config_string(
    "enabled=true&ports.0=8000&ports.1=8001&plugin=(mock?delay=0.1)"
)
# {
#     "enabled": True,
#     "ports": [8000, 8001],
#     "plugin": "mock?delay=0.1",
# }

The function raises ValueError when brackets does not contain two characters, its opening and closing characters are identical, it conflicts with a separator, or brackets in the configuration string are unbalanced.

Type aliases

type ConfigString = str
ImportPath: TypeAlias = str

kiarina.utils.config_registry

from kiarina.utils.config_registry import (
    ConfigAlias,
    ConfigName,
    ConfigRegistry,
    ConfigSpecifier,
    ResolvedConfig,
)

ConfigRegistry

Manage configurations by name, alias, and default, with overrides from configuration strings or keyword arguments. Resolved configurations are deep-copied so the registered sources remain unchanged.

class ConfigRegistry(Generic[T]):
    def __init__(
        self,
        *,
        config_label: str = "Config",
        get_default: Callable[[], ConfigSpecifier | None] | None = None,
        get_aliases: Callable[[], dict[ConfigAlias, ConfigName]] | None = None,
        get_presets: Callable[[], dict[ConfigName, T]] | None = None,
        get_customs: Callable[[], dict[ConfigName, T]] | None = None,
        configure: Callable[[T, dict[str, Any]], T] | None = None,
    ) -> None: ...

    def get_default(self) -> ConfigSpecifier | None: ...

    def get_aliases(self) -> dict[ConfigAlias, ConfigName]: ...

    def list_aliases(self) -> list[ConfigAlias]: ...

    def list_names(self) -> list[ConfigName]: ...

    def register(self, config_name: ConfigName, config: T) -> None: ...

    def unregister(self, config_name: ConfigName) -> None: ...

    def is_registered(self, config_name: ConfigName) -> bool: ...

    def clear(self) -> None: ...

    def get(
        self,
        config_specifier: ConfigSpecifier | None = None,
        **kwargs: Any,
    ) -> T: ...

    def resolve(
        self,
        config_specifier: ConfigSpecifier | None = None,
        **kwargs: Any,
    ) -> ResolvedConfig[T]: ...

get() and resolve() search runtime registrations, custom configurations, and presets in that order. Without configure, overrides are supported for Pydantic BaseModel and dict values. Provide configure to override other value types.

ResolvedConfig

class ResolvedConfig(NamedTuple, Generic[T]):
    name: ConfigName
    config: T

Contains the resolved configuration name and value.

Type aliases

ConfigAlias: TypeAlias = str
ConfigName: TypeAlias = str
ConfigSpecifier: TypeAlias = str

ConfigSpecifier is a string in {ConfigName|ConfigAlias}[?{ConfigString}] format.

kiarina.utils.component_registry

from kiarina.utils.component_registry import (
    ComponentAlias,
    ComponentFactory,
    ComponentInput,
    ComponentName,
    ComponentRegistry,
    ComponentSpecifier,
)

ComponentRegistry

Manage classes and factories by name and create a new instance when needed. Preset and custom components may also be defined using import paths.

class ComponentRegistry(Generic[T]):
    def __init__(
        self,
        *,
        expected_type: object,
        component_label: str = "Component",
        get_default: Callable[[], ComponentSpecifier | None] | None = None,
        get_aliases: Callable[
            [], dict[ComponentAlias, ComponentName]
        ] | None = None,
        get_presets: Callable[
            [], dict[ComponentName, ImportPath]
        ] | None = None,
        get_customs: Callable[
            [], dict[ComponentName, ImportPath]
        ] | None = None,
        factory_wrapper: Callable[
            [ComponentFactory[T], ComponentName, Any], T
        ] | None = None,
    ) -> None: ...

    def get_default(self) -> ComponentSpecifier | None: ...

    def get_aliases(self) -> dict[ComponentAlias, ComponentName]: ...

    def list_aliases(self) -> list[ComponentAlias]: ...

    def list_names(self) -> list[ComponentName]: ...

    def register(
        self,
        component_name: ComponentName,
        factory: ComponentFactory[T],
    ) -> None: ...

    def unregister(self, component_name: ComponentName) -> None: ...

    def get(
        self,
        component_name: ComponentName,
    ) -> ComponentFactory[T] | None: ...

    def clear(self) -> None: ...

    def create(
        self,
        component_name: ComponentName,
        *args: Any,
        **kwargs: Any,
    ) -> T: ...

    def resolve(
        self,
        component_input: ComponentInput[T] | None = None,
        *args: Any,
        **kwargs: Any,
    ) -> T: ...

create() and resolve() always create a new instance and raise ValueError when it does not match expected_type. Factories are searched in runtime registrations, custom components, and presets in that order.

Type aliases

ComponentAlias: TypeAlias = str
ComponentFactory: TypeAlias = Callable[..., T]
ComponentInput: TypeAlias = T | ComponentSpecifier
ComponentName: TypeAlias = str
ComponentSpecifier: TypeAlias = str

ComponentSpecifier is a string in {ComponentName|ComponentAlias}[?{ConfigString}] format.

kiarina.utils.object_registry

from kiarina.utils.object_registry import (
    ObjectAlias,
    ObjectFactory,
    ObjectInput,
    ObjectName,
    ObjectRegistry,
    ObjectSpecifier,
)

ObjectRegistry

Resolve configurations through ConfigRegistry and create objects from them. get() retains and reuses created objects, while create() and resolve() return a new object each time.

class ObjectRegistry(Generic[TObject, TConfig]):
    def __init__(
        self,
        *,
        expected_type: type[TObject],
        object_label: str = "Object",
        get_default: Callable[[], ObjectSpecifier | None] | None = None,
        get_aliases: Callable[[], dict[ObjectAlias, ObjectName]] | None = None,
        get_presets: Callable[[], dict[ObjectName, TConfig]] | None = None,
        get_customs: Callable[[], dict[ObjectName, TConfig]] | None = None,
        configure: Callable[[TConfig, dict[str, Any]], TConfig] | None = None,
        factory: ObjectFactory[TObject, TConfig] | None = None,
    ) -> None: ...

    def get_default(self) -> ObjectSpecifier | None: ...

    def get_aliases(self) -> dict[ObjectAlias, ObjectName]: ...

    def register_config(
        self,
        object_name: ObjectName,
        config: TConfig,
    ) -> None: ...

    def unregister_config(self, object_name: ObjectName) -> None: ...

    def clear_configs(self) -> None: ...

    def is_config_registered(self, object_name: ObjectName) -> bool: ...

    def get_config(
        self,
        object_specifier: ObjectSpecifier | None = None,
    ) -> TConfig: ...

    def list_aliases(self) -> list[ObjectAlias]: ...

    def list_names(self) -> list[ObjectName]: ...

    def register(self, object_name: ObjectName, obj: TObject) -> None: ...

    def unregister(self, object_name: ObjectName) -> None: ...

    def clear(self) -> None: ...

    def is_registered(self, object_name: ObjectName) -> bool: ...

    def get(
        self,
        object_name: ObjectName | ObjectAlias | None = None,
    ) -> TObject: ...

    def create(
        self,
        object_name: ObjectName,
        **kwargs: Any,
    ) -> TObject: ...

    def resolve(
        self,
        object_input: ObjectInput[TObject] | None = None,
        **kwargs: Any,
    ) -> TObject: ...

register() and object creation validate that the value matches expected_type. get() does not accept a specifier containing a ConfigString. Use create() or resolve() to create a new object with configuration overrides.

ObjectFactory

class ObjectFactory(Protocol[TObject_co, TConfig_contra]):
    def __call__(
        self,
        object_name: ObjectName,
        config: TConfig_contra,
        /,
    ) -> TObject_co: ...

A callable that receives the object name and configuration resolved by ObjectRegistry and creates an object.

Type aliases

ObjectAlias: TypeAlias = str
ObjectInput: TypeAlias = TObject | ObjectSpecifier
ObjectName: TypeAlias = str
ObjectSpecifier: TypeAlias = str

ObjectSpecifier is a string in {ObjectName|ObjectAlias}[?{ConfigString}] format.