pydantic-file-settings 0.1.0

Manage your application settings with Pydantic models, storing them in JSON file.

Pydantic File Settings

Manage your application settings with Pydantic models, storing them in a JSON file.

Features

• 🚀 Easy to use: Extend from FileSettings and you're good to go!
• 🔒 Type-safe: Leverage Pydantic's powerful type checking and validation
• 💾 File-based: Store your settings in a JSON file for easy management
• 💪 Flexible: Create, load, and save settings with ease

Installation

pip install pydantic-file-settings

Quick Start

Here's a simple example to get you started:

from pydantic_file_settings import FileSettings
from pydantic import Field

class MyAppSettings(FileSettings):
    app_name: str = "My Awesome App"
    debug_mode: bool = False
    max_connections: int = Field(default=100, ge=1, le=1000)

# Create settings file with default values
settings = MyAppSettings.create("./config")

# Load existing settings
settings = MyAppSettings.load("./config")

# Modify and save settings
settings.debug_mode = True
settings.save()

Usage

Defining Your Settings

Inherit from FileSettings and define your settings as class attributes:

from pydantic_file_settings import FileSettings
from pydantic import Field

class MyAppSettings(FileSettings):
    app_name: str
    debug_mode: bool = False
    max_connections: int = Field(default=100, ge=1, le=1000)

Creating Settings

To create a new settings file:

# Create settings (raises SettingsExistsError if file exists)
settings = MyAppSettings.create("./config")

# Create settings, overwriting if file already exists
settings = MyAppSettings.create("./config", exists_ok=True)

Loading Settings

To load existing settings:

# Load settings (raises SettingsNotFoundError if file doesn't exist)
settings = MyAppSettings.load("./config")

# Load settings, creating file with defaults if it doesn't exist
settings = MyAppSettings.load("./config", create_if_missing=True)

Saving Settings

After modifying settings, save them back to the file:

settings.app_name = "New App Name"
settings.save()

Checking if Settings Exist

You can check if a settings file exists:

if MyAppSettings.exists("./config"):
    print("Settings file found!")

Advanced Usage

Custom Filename

By default, settings are stored in settings.json. You can customize the filename:

class MyAppSettings(FileSettings):
    __FILENAME__ = "app_config.json"
    
    app_name: str = "My App"

Environment Variables

Pydantic File Settings supports loading values from environment variables. Use the validation_alias parameter in Field:

class MyAppSettings(FileSettings):
    api_key: str = Field(default="", validation_alias="MY_APP_API_KEY")

Validation

Leverage Pydantic's validation features:

from pydantic import Field, field_validator

class MyAppSettings(FileSettings):
    port: int = Field(default=8000, ge=1024, le=65535)
    
    @field_validator("port")
    @classmethod
    def port_must_be_even(cls, v: int) -> int:
        if v % 2 != 0:
            raise ValueError("Port must be an even number")
        return v

BaseSettings

The library also exports BaseSettings with validate_assignment=True enabled, useful when you need validation without file storage:

from pydantic_file_settings import BaseSettings

class RuntimeConfig(BaseSettings):
    debug: bool = False

Exception Reference

Exception	Raised by	When
SettingsError	—	Base exception for all settings errors
SettingsNotFoundError	load()	Settings file doesn't exist
SettingsExistsError	create()	Settings file already exists (when exists_ok=False)
ValueError	load()	Settings file contains invalid JSON or data
OSError	save()	Failed to write settings file (e.g., permission denied)

Error Handling Example

from pydantic_file_settings import (
    FileSettings,
    SettingsError,
    SettingsNotFoundError,
    SettingsExistsError,
)

# Handling load errors
try:
    settings = MyAppSettings.load("./config")
except SettingsNotFoundError:
    print("Settings file not found!")
except ValueError:
    print("Invalid settings data!")

# Handling create errors
try:
    settings = MyAppSettings.create("./config")
except SettingsExistsError:
    print("Settings file already exists!")

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgements

• Pydantic for the awesome data validation library

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Made with ❤️ by Ruslan Iskov