Caching: Refactor enterprise query caching middleware to a wire service (#65616)

* define initial service and add to wire

* update caching service interface

* add skipQueryCache header handler and update metrics query function to use it

* add caching service as a dependency to query service

* working caching impl

* propagate cache status to frontend in response

* beginning of improvements suggested by Lean - separate caching logic from query logic.

* more changes to simplify query function

* Decided to revert renaming of function

* Remove error status from cache request

* add extra documentation

* Move query caching duration metric to query package

* add a little bit of documentation

* wip: convert resource caching

* Change return type of query service QueryData to a QueryDataResponse with Headers

* update codeowners

* change X-Cache value to const

* use resource caching in endpoint handlers

* write resource headers to response even if it's not a cache hit

* fix panic caused by lack of nil check

* update unit test

* remove NONE header - shouldn't show up in OSS

* Convert everything to use the plugin middleware

* revert a few more things

* clean up unused vars

* start reverting resource caching, start to implement in plugin middleware

* revert more, fix typo

* Update caching interfaces - resource caching now has a separate cache method

* continue wiring up new resource caching conventions - still in progress

* add more safety to implementation

* remove some unused objects

* remove some code that I left in by accident

* add some comments, fix codeowners, fix duplicate registration

* fix source of panic in resource middleware

* Update client decorator test to provide an empty response object

* create tests for caching middleware

* fix unit test

* Update pkg/services/caching/service.go

Co-authored-by: Arati R. <33031346+suntala@users.noreply.github.com>

* improve error message in error log

* quick docs update

* Remove use of mockery. Update return signature to return an explicit hit/miss bool

* create unit test for empty request context

* rename caching metrics to make it clear they pertain to caching

* Update pkg/services/pluginsintegration/clientmiddleware/caching_middleware.go

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

* Add clarifying comments to cache skip middleware func

* Add comment pointing to the resource cache update call

* fix unit tests (missing dependency)

* try to fix mystery syntax error

* fix a panic

* Caching: Introduce feature toggle to caching service refactor (#66323)

* introduce new feature toggle

* hide calls to new service behind a feature flag

* remove licensing flag from toggle (misunderstood what it was for)

* fix unit tests

* rerun toggle gen

---------

Co-authored-by: Arati R. <33031346+suntala@users.noreply.github.com>
Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

pkg/server/wireexts_oss.go

@@ -17,6 +17,7 @@ import (
 	"github.com/grafana/grafana/pkg/services/anonymous/anonimpl"
 	"github.com/grafana/grafana/pkg/services/auth"
 	"github.com/grafana/grafana/pkg/services/auth/authimpl"
+	"github.com/grafana/grafana/pkg/services/caching"
 	"github.com/grafana/grafana/pkg/services/datasources"
 	"github.com/grafana/grafana/pkg/services/datasources/permissions"
 	datasourceservice "github.com/grafana/grafana/pkg/services/datasources/service"
@@ -88,6 +89,8 @@ var wireExtsBasicSet = wire.NewSet(
 	pluginsintegration.WireExtensionSet,
 	publicdashboardsService.ProvideServiceWrapper,
 	wire.Bind(new(publicdashboards.ServiceWrapper), new(*publicdashboardsService.PublicDashboardServiceWrapperImpl)),
+	caching.ProvideCachingService,
+	wire.Bind(new(caching.CachingService), new(*caching.OSSCachingService)),
 )
 
 var wireExtsSet = wire.NewSet(