[API Proposal]: Extend IMemoryCache to also provide keys/provider info

[thompson-tomo]

Background and motivation

I like what has been done with #36554 however for me it is not enough to be able to implement an actuator to provide information about the cache as done in spring boot.

I would like the method to be available as part of the interface so that i have a consistent way to get the keys and the metadata regardless of the provider.

API Proposal

Interface extension

namespace System.Collections.Generic;

IEnumerable<CacheItem> GetCacheItems => new IEnumerable<CacheItem>();

new class

public class CacheItem
{
    public string ProviderName
    public string StorageType
    public object Key
}

API Usage

foreach (var item in _memoryCache.GetCacheItems.ToList())
{
    //build object as per actuator needs which includes 
}

Alternative Designs

• Default implementation throws a not implemented exception

Risks

Should be low risk as not a breaking change by providing default implementation.

[ghost]

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Issue Details

---

### Background and motivation I like what has been done with #36554 however for me it is not enough to be able to implement an actuator to provide information about the cache as done in spring boot. I would like the method to be available as part of the interface so that i have a consistent way to get the keys and the metadata regardless of the provider. ### API Proposal Interface extension ```csharp namespace System.Collections.Generic; IEnumerable GetCacheKeys => new IEnumerable(); ``` new class ```csharp public class CacheItem { public string ProviderName public string StorageType public object Key } ``` ### API Usage ```csharp foreach (var item in _memoryCache.GetCacheKeys.ToList()) { //build object as per actuator needs which includes } ``` ### Alternative Designs _No response_ ### Risks Should be low risk as not a breaking change by providing default implementation.

Author:	thompson-tomo
Assignees:	-
Labels:	`api-suggestion`, `untriaged`, `area-Extensions-Caching`
Milestone:	-

[jozkee]

Is CacheItem a view of a CacheEntry? What's ProviderName and StorageType? Can you be more specific about the extension method you are proposing here? In which static type will it live?

[dotnet-policy-service[bot]]

This issue has been marked needs-author-action and may be missing some important information.

[julealgon]

@thompson-tomo if you want to know what happens with the IMemoryCache object, why don't you just create a simple decorator for it that intercepts the calls and stores the information you need before/after each method is executed?

From your description, introspection on the calls (and callbacks) should be enough to be able to provide a "view" of the cache.

Also, instead of viewing the entire state of the cache, I believe it would be better to have metrics around the cache so that you could graph them in observability tools.

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