MutableConfig 1.0.3

MutableConfig

A lightweight and extensible .NET/C# library for runtime configuration management, supporting type-safe mapping of C# classes to JSON files.

About

MutableConfig is a configuration management library for the .NET/C# environment. It is designed to allow applications to easily load, modify, and persist configuration items at runtime without needing to restart or redeploy. It supports organizing configurations into a hierarchical structure, dynamic updates, and is designed to be lightweight and extensible.

Common use cases include:

• 🔄 Runtime Configuration Updates: When you have an application and need to change certain configuration items during runtime without stopping the application.

• 🧩 C# to JSON Mapping: Map C# types to JSON files one by one, enabling strong-typed configuration access.

• 🌐 Centralized Multi-Module Management: Want to centrally manage configurations across multiple modules/environments and support features like hot updates.

Key Features

Here are some of the key features of this library:

• ⚙️ Runtime Mutable Configuration: Supports easily modifying configuration items with code during the application's runtime without needing to restart the application.

• 🧩 Configuration File Hierarchy and Typed Access:

  • Maps C# classes to JSON files one-to-one, providing strong-typed access.
  • Configuration fields can be read and modified like regular C# objects.
  • Changes are persisted to the JSON file explicitly via the SaveChanges() method, keeping the file hierarchy consistent with the type definitions.

• 💾 Persistence and Recovery Mechanism: Configuration changes can be saved persistently, allowing the previous state to be restored on the next startup.

• 🪶 Lightweight: Uses only core .NET features without relying on many external libraries, making it easy to embed and extend.

How to Use

Installation

dotnet add package MutableConfig

Add to Program.cs:

using MutableConfig;

// Configuration Data Preparation
const string configFolderName = "Config";
var basePath = Path.Join(AppContext.BaseDirectory, configFolderName);

var defaultAppSettingsConfig = new AppSettingsConfig {
    AppName = "MutableConfig Sample App", Version = "1.0.0", EnableDebug = true
};
var defaultDatabaseConfig = new DatabaseConfig {
    Host = "localhost", Port = 5432
};

/*
 * Dependency Injection
 *
 * AppSettingsConfig is a custom configuration class.
 * Once registered through dependency injection, MutableConfig will ensure that
 * an "AppSettingsConfig.json" file exists under the specified basePath.
 *
 * On the first run, if the configuration file does not exist, it will be created
 * using the default values provided through SetupDefaultConfigIfNotExists().
 *
 * Configuration objects are fully mutable at runtime, and changes made to them
 * are tracked within their corresponding ConfigContext<T>. To persist updates
 * to the underlying JSON file, you explicitly call SaveChanges() on the context.
 */
builder.Services.AddConfigContext<AppSettingsConfig>(opt =>
    opt.SetBasePath(basePath)
        .SetupDefaultConfigIfNotExists(defaultAppSettingsConfig));

Example

You can find a complete working example here:

👉 Sample Code

This sample demonstrates how to define a configuration class, bind it to a JSON file, and modify it at runtime while keeping both sides synchronized.

Main Types

The main types provided by this library are:

• ConfigContext<T> — A configuration context for a specific type. Use ConfigContext<T> for a particular configuration class.
• ConfigContextOptions<T> — Options for configuring a ConfigContext<T>.

Feedback & Contributing

MutableConfig is released as open source under the Apache-2.0 license. Bug reports and contributions are welcome at the GitHub repository.