redis

name	redis
description	Implements Redis caching, session management, and distributed coordination for the Sorcha platform. Use when: Adding caching layers, token revocation, rate limiting, SignalR backplane, or distributed state.
allowed-tools	Read, Edit, Write, Glob, Grep, Bash, mcp__context7__resolve-library-id, mcp__context7__query-docs

Redis Skill

Sorcha uses Redis via StackExchange.Redis for caching, token revocation tracking, rate limiting, and distributed coordination. All services share a single Redis instance managed by .NET Aspire with circuit breaker resilience.

Quick Start

Aspire Configuration

// src/Apps/Sorcha.AppHost/AppHost.cs
var redis = builder.AddRedis("redis")
    .WithRedisCommander();

// Reference from any service
var blueprintService = builder.AddProject<Projects.Sorcha_Blueprint_Service>()
    .WithReference(redis);

Cache Store Usage

// Inject ICacheStore from Sorcha.Storage.Redis
public class MyService(ICacheStore cache)
{
    public async Task<User?> GetUserAsync(string id)
    {
        return await cache.GetAsync<User>($"user:{id}");
    }
    
    public async Task SetUserAsync(User user)
    {
        await cache.SetAsync($"user:{user.Id}", user, TimeSpan.FromMinutes(15));
    }
}

Direct IConnectionMultiplexer

// For operations beyond ICacheStore (Sets, rate limiting, etc.)
public class TokenService(IConnectionMultiplexer redis)
{
    private readonly IDatabase _db = redis.GetDatabase();
    
    public async Task TrackTokenAsync(string userId, string jti)
    {
        await _db.SetAddAsync($"auth:user_tokens:{userId}", jti);
    }
}

Key Concepts

Concept	Usage	Example
Key prefix	Namespace isolation	sorcha:, auth:
TTL	Automatic expiration	TimeSpan.FromMinutes(15)
Circuit breaker	Graceful degradation	Breaks after 5 failures
Sets	Token tracking	SetAddAsync, SetMembersAsync
Counters	Rate limiting	StringIncrementAsync

Common Patterns

Rate Limiting

When: Protecting auth endpoints from brute force.

public async Task<bool> IsRateLimitedAsync(string identifier)
{
    var key = $"auth:failed:{identifier}";
    var count = await _db.StringIncrementAsync(key);
    
    if (count == 1)
        await _db.KeyExpireAsync(key, TimeSpan.FromSeconds(60));
    
    return count >= MaxFailedAttempts;
}

Token Revocation

When: Invalidating JWTs before expiration.

public async Task RevokeTokenAsync(string jti, DateTimeOffset expiresAt)
{
    var ttl = expiresAt - DateTimeOffset.UtcNow;
    if (ttl > TimeSpan.Zero)
        await _db.StringSetAsync($"auth:revoked:{jti}", "revoked", ttl);
}

IDistributedCache is a separate registration from IConnectionMultiplexer

builder.AddRedisClient("redis") wires up IConnectionMultiplexer and IDatabase — sufficient for direct StackExchange.Redis use. It does NOT register Microsoft.Extensions.Caching.Distributed.IDistributedCache. Code that depends on IDistributedCache will throw InvalidOperationException: Unable to resolve service for type 'IDistributedCache' at the first request — not at boot.

Add the distributed-cache overlay explicitly, sharing the same connection name:

builder.AddRedisClient("redis");
builder.AddRedisDistributedCache("redis");  // adds IDistributedCache → Redis

Requires the Aspire.StackExchange.Redis.DistributedCaching package alongside the base Aspire.StackExchange.Redis.

Unit-test trap that masks this: tests that construct the SUT directly with new MemoryDistributedCache(Options.Create(new MemoryDistributedCacheOptions())) bypass the DI graph entirely. The test passes; the container fails at runtime. If a service under test depends on IDistributedCache, also add a thin DI-startup test (or an integration test against a TestHost) that asserts the registration exists — not just one that mocks past it. Feature 124 PR #697 was the cautionary tale: 6 unit tests with MemoryDistributedCache green, production 500'd on every endpoint call.

See Also

• patterns - Caching, resilience, key naming
• workflows - Setup, testing, debugging

Related Skills

• aspire - Redis resource configuration and service discovery
• jwt - Token revocation integration
• signalr - Redis backplane for scale-out
• docker - Redis container configuration

Documentation Resources

Fetch latest Redis and StackExchange.Redis documentation with Context7.

How to use Context7:

1. Use mcp__context7__resolve-library-id to search for "StackExchange.Redis" or "redis"
2. Prefer website documentation (/websites/redis_io) for concepts
3. Use /stackexchange/stackexchange.redis for .NET-specific patterns

Library IDs:

• /stackexchange/stackexchange.redis - .NET client (344 snippets)
• /websites/redis_io - Redis concepts (29k+ snippets)

Recommended Queries:

• "Connection pooling multiplexer patterns best practices"
• "Caching patterns TTL expiration strategies"
• "Pub/Sub patterns distributed systems"