SpringBoot Create a cache actuator endpoint.

Hi,

I'd like to have a /cache actuator endpoint that will list all the cache regions will all the statistics for each cache region. More specifically:

GET /cache
[{
  "id" : "simpleCMSWidgetData",
  "stats" : {
    "AverageGetTime" : 0.0,
    "CacheHitPercentage" : 77.27273,
    "CacheEvictions" : 0,
    "AverageRemoveTime" : 0.0,
    "CacheMisses" : 30,
    "AveragePutTime" : 35.89833,
    "CacheMissPercentage" : 22.727274,
    "CacheHits" : 102,
    "CacheRemovals" : 0,
    "CachePuts" : 30,
    "CacheGets" : 132
  }
}, {
  "id" : "productData",
  "stats" : {
    "AverageGetTime" : 0.0,
    "CacheHitPercentage" : 50.0,
    "CacheEvictions" : 0,
    "AverageRemoveTime" : 0.0,
    "CacheMisses" : 1,
    "AveragePutTime" : 33.119,
    "CacheMissPercentage" : 50.0,
    "CacheHits" : 1,
    "CacheRemovals" : 0,
    "CachePuts" : 1,
    "CacheGets" : 2
  }
} ]

and

GET /cache/productData
{
  "id" : "productData",
  "stats" : {
    "AverageGetTime" : 0.0,
    "CacheHitPercentage" : 50.0,
    "CacheEvictions" : 0,
    "AverageRemoveTime" : 0.0,
    "CacheMisses" : 1,
    "AveragePutTime" : 33.119,
    "CacheMissPercentage" : 50.0,
    "CacheHits" : 1,
    "CacheRemovals" : 0,
    "CachePuts" : 1,
    "CacheGets" : 2
  }
}

and

DELETE /cache

would clear all the cache

and

DELETE /cache/productData

would clear the given cache region.

Comment From: snicoll

Not all cache library exposes that level of information I guess.

I also think @olivergierke has some concerns regarding DELETE on a Collection.

Comment From: philwebb

@paranoiabla What cache library do you currently use?

Comment From: ptahchiev

@philwebb I use jcache abstraction, but underneath is hazelcast.

Comment From: snicoll

So we have added the cache metrics in the actuator as part of #2633 - As far as the management endpoint to actually clear caches, I am not sure how we would do that.

Comment From: maximede

Hello, I just created a WIP branch for the clear cache endpoint. ( see https://github.com/maximede/spring-boot/commit/77ebbd17fcd2bac5e589f6acba8fd5228861b5c7 ) It still needs a bit of work ( like showing all the cleared cache in the response, adding a few test) but I wanted to see if this was something that could be useful (it would be for me) , and if it's the correct way to do it.

I'm basically calling cache.clear() on all available caches. It should work with any cache who implement org.springframework.cache.Cache#clear

There is also an MvcEndpoint that currently respond on POST /clear_cache (should be DELETE)

A nice improvement would be to be able to choose which cache(s) we want to clear.

Let me know what you think

Comment From: maximede

Any insight about my commit ?

Comment From: snicoll

Duplicate of #12216

Comment From: cdalexndr

Missing documentation for this feature: https://docs.spring.io/spring-boot/docs/2.4.3/reference/html/production-ready-features.html#production-ready-endpoints Is it still present in recent versions?

Comment From: snicoll

I don't understand any of that. The link you provided has an entry for the cache endpoint. This section links to additional details for each endpoint including the caches endpoint: https://docs.spring.io/spring-boot/docs/2.4.3/actuator-api/htmlsingle/#caches

Comment From: cdalexndr

@snicoll I opened docs from Spring Boot Reference Documentation where is only one entry for Spring Boot Actuator so I thought it contains the whole docs for actuator. Didn't bother to read through whole docs, so I searched cache keyword and didn't found any info about this feature. It seems that there are more stacked doc pages, thanks.