[FEATURE] Expose configured services, e.g. for distributed cache and backplane

[angularsen]

Problem

When using services.AddFusionCache().TryWithAutoSetup() it is not always clear which registered services are actually used by any given FusionCache instance.

For instance, in our tests we re-configure services.AddFusionCache() in order to disable Redis as distributed cache for our tests. This tripped me up when trying to write tests to create a repro for our issue, so I wanted to add some logging in .WithPostSetup(ServiceProvider, FusionCache) to log exactly what services are used, not just true/false on HasBackplane and HasDistributedCache.

Right now I just need the service type for each, but I imagine it could be useful to access the actual service object too, in order to call methods to query its config or state.

Solution

Public property accessors for the underlying service used by FusionCache, particularly for distributed cache and backplane. There are a number of services configured in FusionCacheBuilder.Build that are not publicly available in FusionCache when built.

Alternatives

Manual inspection during debugging, reflection to get internal properties, or calling sp.GetService<IDistributedCache>() and sp.GetService<IFusionCacheBackplane>() hoping the registered services are actually used and not overridden with WithBackplane() and WithDistributedCache().

[jodydonetti]

Hi @angularsen this is something I probably can do without exposing too much (in terms of future evolution): let me think about it a little and will get back to you, thanks.

[jodydonetti]

... although, that would technically be a breaking change 🤔

[jodydonetti]

Hi @angularsen , after thinking about this for some time I decided to implement the needed changes, since although changing the IFusionCache interface is a breaking change, it's a very minor one, it's in the root package and reasonably the all the implementations (meaning: FusionCache and NullFusionCache) are made - and update - by me.

You can see the related issues here and here.

Will include them in the next v2.2.0 preview so you can take a look at them.

[angularsen]

Great! Will check it out.

[jodydonetti]

Hi all, v2.2.0-preview-1 is out 🥳

[jodydonetti]

Hi @angularsen , have you been able to check this out and see if everything is looking good?

[angularsen]

Yes, this helps, thanks! ❤

It gets me to the FusionCache abstractions for logging purposes:

• ZiggyCreatures.Caching.Fusion.Backplane.StackExchangeRedis.RedisBackplane
• Microsoft.Extensions.Caching.StackExchangeRedis.RedisCacheImpl

In addition, I've found it useful to also log the StackExchange.Redis connection details and library version given by IConnectionMultiplexer.ToString(), and this was easiest to do in:

• services.AddStackExchangeRedisCache(o => o.ConnectionMultiplexerFactory = {...})
• services.AddFusionCacheStackExchangeRedisBackplane(o => o.ConnectionMultiplexerFactory = {...})

I guess I originally wanted to access the IConnectionMultiplexer via FusionCache, but since RedisCacheImpl is internal, I'd have to resort to reflection to obtain it anyway.

At any rate my logging needs are now well covered 😅

[jodydonetti]

Hi all, v2.2.0 is out 🥳
And for the corresponding LTS-only release, there's v2.0.2.