ConfigHotReloadEngine 1.0.1

.NET Configuration Hot Reload Engine

A pure .NET, single-node configuration management component that supports safe runtime configuration reloading without application restarts.

This project focuses on correctness, thread safety, and clean design rather than infrastructure or UI concerns.

What Problem This Solves

Most applications load configuration once at startup. Any change requires a full restart, which is not always desirable.

This project provides a simple mechanism to:

• Load strongly typed configuration from JSON
• Keep configuration immutable and safe in memory
• Detect file changes at runtime
• Reload configuration atomically
• Notify consumers when configuration changes

All within a single .NET process, without external dependencies.

Core Concepts

The system revolves around a single idea: there is always exactly one valid configuration instance in memory.

Configuration updates are applied atomically: either the new configuration is fully valid and replaces the old one, or the old configuration remains active.

Consumers never see partial or invalid state.

Features

• Strongly typed configuration loading
• File-based configuration source (JSON)
• Automatic hot reload on file changes
• Thread-safe access to configuration
• Atomic config replacement
• Change notification for subscribers
• Graceful handling of invalid configuration files

Example Usage

1. dotnet add package ConfigHotReloadEngine

2. Create an AppConfig.json in the root of your project.

// See https://aka.ms/new-console-template for more information
using ConfigHotReloadEngine;

var provider = new ConfigurationProvider("./AppConfig.json");

provider.OnChange(config =>
{
    foreach (var kvp in config.AsObject())
    {
        Console.WriteLine($"{kvp.Key}: {kvp.Value}");
    }
    Console.WriteLine("---- Configuration Reloaded ----");
});

// Print initial config
// Print initial config
foreach (var kvp in provider.Current.AsObject())
{
    Console.WriteLine($"{kvp.Key}: {kvp.Value}");
}

await Process.Start();

ASP.NET Core example

Even though ASP.NET Core has IConfiguration and reloadOnChange: true for appsettings.json, it implements its own watcher internally.

Why? Because:

• They don’t want to restart the app
• They want thread-safe, in-memory updates
• They notify parts of the app (like DI services) when config changes

This ConfigurationProvider is essentially a simplified, custom version of that mechanism.