LevelUp.ServiceDefaults.Caching 0.3.5

LevelUp.ServiceDefaults.Caching

Opt-in caching satellite for LevelUp.ServiceDefaults. Wires FusionCache's .AsHybridCache() adapter as the application's HybridCache, giving an in-process L1 with an optional Redis L2 and a Redis backplane for cross-instance invalidation. The FusionCache/Redis dependencies are isolated here so they stay out of the AOT-safe core.

Usage

builder.AddLevelUpServiceDefaults()
       .AddLevelUpHybridCache(); // L1 always; L2 + backplane only with ConnectionStrings:cache

The L2 distributed cache and the invalidation backplane self-disable when no Redis connection resolves: the call registers an L1-only cache and does not throw, keeping the canonical shim uniform across services. At host start a log line reports the selected mode (Information for L1 + L2 + backplane, Warning for L1-only) so the disable is never silent.

Entry points

Three overloads route through one private core, so the wiring is identical across surfaces:

// 1. Host builder (returns the builder, so the fluent chain keeps compiling).
builder.AddLevelUpHybridCache(o => o.ConnectionName = "redis");

// 2. IServiceCollection + IConfiguration — resolves ConnectionStrings:{ConnectionName}.
//    Use this when caching is registered in an IServiceCollection extension.
services.AddLevelUpHybridCache(configuration, o => o.ConnectionName = "redis");

// 3. IServiceCollection + an explicit connection string (used verbatim, no lookup).
services.AddLevelUpHybridCache(redisConnectionString);

The builder overload returns TBuilder (so builder.AddLevelUpServiceDefaults().AddLevelUpHybridCache() chains); the IServiceCollection overloads return IServiceCollection.

Overload resolution: a bare null literal is ambiguous (CS0121) between the IConfiguration and string? overloads. Cast it to pick one, e.g. services.AddLevelUpHybridCache((string?)null).

Options (LevelUpCacheOptions)

Namespacing shared Redis with InstanceName

When several apps share one Redis, set InstanceName via ConfigureRedis to prefix this app's L2 keys:

services.AddLevelUpHybridCache(configuration, o =>
{
    o.ConnectionName = "redis";
    o.ConfigureRedis = redis => redis.InstanceName = "tenantA:";
});

There is no implicit key-prefix default, so the at-rest key shape is unchanged unless you opt in here.

ConfigureRedis precedence vs the shared multiplexer

The L2 and the backplane share one connect-once IConnectionMultiplexer (one connection, per FusionCache's own guidance). The opinionated defaults — including the shared-multiplexer factory and the resolved connection — are applied first; your ConfigureRedis callback runs last, so consumer values win. Note the precedence consequence: a callback that re-sets ConnectionMultiplexerFactory or Configuration replaces the shared factory and forfeits connection sharing with the backplane. Prefer tuning ConfigurationOptions/InstanceName over replacing the factory.

The L2 stays private to FusionCache

The Redis L2 is constructed inline and held by FusionCache only — the satellite registers no application-wide IDistributedCache. This is deliberate: registering a global IDistributedCache would silently re-home ASP.NET session / data-protection / output-cache onto Redis and let sibling IDistributedCache consumers write plaintext into the encrypted L2's Redis. GetService<IDistributedCache>() is therefore unaffected by AddLevelUpHybridCache. Program against the GA HybridCache abstraction the satellite registers.