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/api/plugins_test.go

@@ -30,7 +30,9 @@ import (
 	"github.com/grafana/grafana/pkg/plugins/manager/store"
 	"github.com/grafana/grafana/pkg/plugins/pluginscdn"
 	ac "github.com/grafana/grafana/pkg/services/accesscontrol"
+	"github.com/grafana/grafana/pkg/services/caching"
 	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/org"
 	"github.com/grafana/grafana/pkg/services/org/orgtest"
 	"github.com/grafana/grafana/pkg/services/pluginsintegration/pluginaccesscontrol"
@@ -371,9 +373,11 @@ func Test_GetPluginAssets(t *testing.T) {
 
 func TestMakePluginResourceRequest(t *testing.T) {
 	hs := HTTPServer{
-		Cfg:          setting.NewCfg(),
-		log:          log.New(),
-		pluginClient: &fakePluginClient{},
+		Cfg:            setting.NewCfg(),
+		log:            log.New(),
+		pluginClient:   &fakePluginClient{},
+		cachingService: &caching.OSSCachingService{},
+		Features:       &featuremgmt.FeatureManager{},
 	}
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
 
@@ -399,6 +403,8 @@ func TestMakePluginResourceRequestSetCookieNotPresent(t *testing.T) {
 		pluginClient: &fakePluginClient{
 			headers: map[string][]string{"Set-Cookie": {"monster"}},
 		},
+		cachingService: &caching.OSSCachingService{},
+		Features:       &featuremgmt.FeatureManager{},
 	}
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
 	resp := httptest.NewRecorder()
@@ -433,6 +439,8 @@ func TestMakePluginResourceRequestContentTypeUnique(t *testing.T) {
 						"x-another": {"hello"},
 					},
 				},
+				cachingService: &caching.OSSCachingService{},
+				Features:       &featuremgmt.FeatureManager{},
 			}
 			req := httptest.NewRequest(http.MethodGet, "/", nil)
 			resp := httptest.NewRecorder()
@@ -456,9 +464,11 @@ func TestMakePluginResourceRequestContentTypeEmpty(t *testing.T) {
 		statusCode: http.StatusNoContent,
 	}
 	hs := HTTPServer{
-		Cfg:          setting.NewCfg(),
-		log:          log.New(),
-		pluginClient: pluginClient,
+		Cfg:            setting.NewCfg(),
+		log:            log.New(),
+		pluginClient:   pluginClient,
+		cachingService: &caching.OSSCachingService{},
+		Features:       &featuremgmt.FeatureManager{},
 	}
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
 	resp := httptest.NewRecorder()