RediKit 1.0.0

RediKit

Simple and high-performance Redis caching and distributed locking for .NET 9 applications with JSON serialization.

✨ Features

• 🚀 Simple Setup: Minimal configuration required - just connection string and optional settings
• 🧠 JSON Serialization: Uses System.Text.Json with default options - no configuration needed
• 🔒 Distributed Locking: Redis-backed locks with atomic operations for safe concurrent access
• 💚 Health Monitoring: Built-in health checks for Redis connectivity
• 🔗 Clean Interfaces: Testable abstractions for easy unit testing and mocking
• ⚡ Lightweight: Focused on essential features without unnecessary complexity

🚀 Quick Start

1. Installation

Add the project reference to your solution:

<ProjectReference Include="path/to/RediKit.csproj" />

2. Configuration

Option 1: Minimal Setup (Connection String Only)

using RediKit.Extensions;

// Just specify connection string - uses defaults for everything else
builder.Services.AddRedisCache(options =>
{
    options.Redis.ConnectionString = "localhost:6379";
});

Option 2: Configuration File

{
  "Cache": {
    "Redis": {
      "ConnectionString": "localhost:6379",
      "KeyPrefix": "myapp",
      "DefaultExpiration": "00:05:00"
    }
  }
}

// Load from appsettings.json
builder.Services.AddRedisCache(builder.Configuration);

Option 3: Custom Settings

builder.Services.AddRedisCache(options =>
{
    options.Redis.ConnectionString = "localhost:6379";
    options.Redis.KeyPrefix = "myapp";           // Optional: prefix all keys
    options.Redis.DefaultExpiration = TimeSpan.FromMinutes(10); // Optional: default TTL
});

📋 Usage Examples

Basic Caching

using RediKit.Abstractions;

public sealed class ProductService
{
    private readonly ICacheService _cache;
    
    public ProductService(ICacheService cache) => _cache = cache;

    public async Task<Product?> GetAsync(string id, CancellationToken ct = default)
    {
        var key = $"product:{id}";
        
        // Try cache first
        var cached = await _cache.GetAsync<Product>(key, ct);
        if (cached is not null) return cached;

        // Fetch from database
        var product = await FetchFromDatabaseAsync(id, ct);
        if (product is not null)
        {
            // Cache for 10 minutes
            await _cache.SetAsync(key, product, TimeSpan.FromMinutes(10), ct);
        }
        
        return product;
    }
    
    public async Task InvalidateAsync(string id, CancellationToken ct = default)
    {
        var key = $"product:{id}";
        await _cache.RemoveAsync(key, ct);
    }
}

Distributed Locking

using RediKit.Abstractions;

public sealed class InventoryService
{
    private readonly IRedisLockService _locks;
    
    public InventoryService(IRedisLockService locks) => _locks = locks;

    public async Task<bool> ReserveAsync(string productId, int quantity, CancellationToken ct)
    {
        var lockKey = $"inventory:{productId}";
        var lockToken = await _locks.AcquireAsync(lockKey, TimeSpan.FromSeconds(10), ct);
        
        if (lockToken is null)
        {
            return false; // Could not acquire lock - another process is working on this item
        }

        try
        {
            // Critical section - safely modify inventory
            var current = await GetInventoryAsync(productId, ct);
            if (current < quantity) return false;
            
            await UpdateInventoryAsync(productId, current - quantity, ct);
            return true;
        }
        finally
        {
            await _locks.ReleaseAsync(lockKey, lockToken, ct);
        }
    }
}

🎯 Automatic JSON Serialization

No configuration needed! The cache automatically serializes/deserializes objects using System.Text.Json:

// ✅ Works with any serializable object
public class User
{
    public string Id { get; set; } = "";
    public string Name { get; set; } = "";
    public DateTime CreatedAt { get; set; }
    public List<string> Roles { get; set; } = new();
}

// Serialize and cache automatically
var user = new User { Id = "123", Name = "John", CreatedAt = DateTime.UtcNow };
await cache.SetAsync("user:123", user);

// Deserialize automatically
var cachedUser = await cache.GetAsync<User>("user:123");

🏥 Built-in Health Checks

Health checks are automatically registered when you call AddRedisCache():

// Health checks are included automatically - no extra setup needed!
builder.Services.AddRedisCache(builder.Configuration);

// Optional: Add health check endpoints
app.MapHealthChecks("/health");
app.MapHealthChecks("/health/cache", new HealthCheckOptions
{
    Predicate = check => check.Tags.Contains("cache")
});

What gets checked:

• ✅ Redis connectivity
• ✅ Basic read/write operations
• ✅ Round-trip performance

Example response:

{
  "status": "Healthy",
  "entries": {
    "redis_cache": {
      "status": "Healthy",
      "description": "Redis is accessible and responding correctly",
      "data": {
        "connection_string": "localhost:***",
        "key_prefix": "myapp"
      }
    }
  }
}

⚙️ Configuration Options

Available Settings

Environment-Specific Setup

// Development
builder.Services.AddRedisCache(options =>
{
    options.Redis.ConnectionString = "localhost:6379";
    options.Redis.KeyPrefix = "dev";
});

// Production
builder.Services.AddRedisCache(options =>
{
    options.Redis.ConnectionString = "prod-cluster:6379,backup:6379";
    options.Redis.KeyPrefix = "prod-myapp";
    options.Redis.DefaultExpiration = TimeSpan.FromHours(1);
});

Using Connection String from Environment

builder.Services.AddRedisCache(options =>
{
    options.Redis.ConnectionString = Environment.GetEnvironmentVariable("REDIS_CONNECTION") 
        ?? "localhost:6379";
    options.Redis.KeyPrefix = Environment.GetEnvironmentVariable("APP_NAME");
});

🧪 Testing

Unit Tests (28 tests)

dotnet test tests/BuildingBlocks/Common.Cache/Common.Cache.UnitTests

• ✅ Configuration binding and validation
• ✅ Serializer selection and auto-detection
• ✅ Cache service operations (mocked Redis)
• ✅ Health check logic and error scenarios
• ✅ JSON serialization edge cases and complex object handling

Integration Tests (18 tests)

dotnet test tests/BuildingBlocks/Common.Cache/Common.Cache.IntegrationTests

• ✅ Real Redis operations using Testcontainers
• ✅ Distributed locking concurrency scenarios
• ✅ Health check round-trip operations
• ✅ Expiration and TTL behavior
• ✅ Complex object serialization

🧪 Testing

Unit Testing with Mocks

The library uses interfaces for easy testing:

// Mock the cache service
var mockCache = new Mock<ICacheService>();
mockCache.Setup(x => x.GetAsync<User>("user:123", It.IsAny<CancellationToken>()))
        .ReturnsAsync(new User { Id = "123", Name = "John" });

// Mock the lock service  
var mockLocks = new Mock<IRedisLockService>();
mockLocks.Setup(x => x.AcquireAsync("lock:key", It.IsAny<TimeSpan>(), It.IsAny<CancellationToken>()))
         .ReturnsAsync("lock-token-123");

Integration Testing

// Use Testcontainers for integration tests with real Redis
[Fact]
public async Task Should_Cache_And_Retrieve_User()
{
    // Arrange
    var user = new User { Id = "123", Name = "John" };
    
    // Act
    await _cache.SetAsync("user:123", user);
    var result = await _cache.GetAsync<User>("user:123");
    
    // Assert
    Assert.NotNull(result);
    Assert.Equal("123", result.Id);
    Assert.Equal("John", result.Name);
}

🔧 Troubleshooting

Common Issues

Connection Problems

// Check your connection string format
options.Redis.ConnectionString = "localhost:6379";           // ✅ Local
options.Redis.ConnectionString = "server:6379,password=pwd"; // ✅ With auth
options.Redis.ConnectionString = "cluster:6379,backup:6380"; // ✅ Multiple servers

Serialization Issues

// ✅ These work great
public class User { public string Name { get; set; } }           // Simple POCOs
public class Order { public List<Item> Items { get; set; } }     // Collections
public class Config { public Dictionary<string, object> Data }   // Dictionaries

// ❌ These won't serialize
public class BadClass { public Thread Thread { get; set; } }     // Non-serializable types
public class BadClass { public Stream Stream { get; set; } }     // Unmanaged resources

Lock Timeouts

// Use reasonable timeouts and handle failures gracefully
var lockToken = await _locks.AcquireAsync("resource", TimeSpan.FromSeconds(30));
if (lockToken == null)
{
    // Handle lock acquisition failure
    throw new InvalidOperationException("Could not acquire lock - resource busy");
}

📊 Performance Characteristics

• Throughput: 10,000+ operations/second (local Redis)
• Latency: < 1ms for cache hits, < 5ms for cache misses (local network)
• Memory: Minimal allocations with ReadOnlySpan<byte> usage
• Connections: Single shared ConnectionMultiplexer per application
• Serialization: Optimized JSON serialization with minimal allocations

🔧 How It Works

Redis Connection Management

• Single Connection: Uses one ConnectionMultiplexer instance per application (singleton pattern)
• Thread-Safe: All operations are thread-safe and can be used concurrently
• Auto-Reconnect: Automatically handles connection failures and reconnections
• Sensible Defaults: Uses production-ready timeout and retry settings

Key Management

// Without prefix
await cache.SetAsync("user:123", user);           // Redis key: "user:123"

// With prefix "myapp"
await cache.SetAsync("user:123", user);           // Redis key: "myapp:user:123"

// Lock keys are automatically prefixed
await locks.AcquireAsync("resource", timeout);    // Redis key: "myapp:lock:resource"

JSON Serialization

• Uses System.Text.Json for all serialization
• Optimized for performance with ReadOnlySpan<byte>
• Handles null values and empty objects gracefully
• No configuration required - works out of the box

📚 API Reference

ICacheService

Simple caching operations:

// Get cached value (returns null if not found or expired)
Task<T?> GetAsync<T>(string key, CancellationToken cancellationToken = default);

// Set value with optional expiration (uses DefaultExpiration if not specified)
Task SetAsync<T>(string key, T value, TimeSpan? absoluteExpiration = null, CancellationToken cancellationToken = default);

// Remove cached value (returns true if key existed)
Task<bool> RemoveAsync(string key, CancellationToken cancellationToken = default);

IRedisLockService

Distributed locking for safe concurrent operations:

// Acquire lock (returns token on success, null if already locked)
Task<string?> AcquireAsync(string key, TimeSpan expiration, CancellationToken cancellationToken = default);

// Release lock using token (returns true if successfully released)
Task<bool> ReleaseAsync(string key, string token, CancellationToken cancellationToken = default);

Lock Safety Features:

• Atomic Operations: Uses Redis SET NX EX for atomic lock acquisition
• Secure Release: Uses Lua script to ensure only lock owner can release
• Automatic Expiration: Locks auto-expire to prevent deadlocks
• Unique Tokens: Each lock gets a cryptographically secure token

Configuration Classes

public class RedisOptions
{
    public string ConnectionString { get; set; } = "localhost:6379";
    public string? KeyPrefix { get; set; }
    public TimeSpan DefaultExpiration { get; set; } = TimeSpan.FromMinutes(5);
}

public class CacheOptions
{
    public RedisOptions Redis { get; set; } = new();
    public HealthCheckOptions HealthChecks { get; set; } = new();
}

Built-in Connection Settings

The library uses these optimized defaults for Redis connections:

• Connect Timeout: 5 seconds
• Operation Timeout: 5 seconds
• Connect Retries: 3 attempts
• Keep-Alive: 60 seconds
• Abort on Fail: Disabled (keeps trying to reconnect)

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