Plugins: Add synchronous CDN plugin loader (#99096)

* WIP

* Run plugin validations and validation steps sequentially if feature is off

* Remove dependency between sources.Service and pluginscdn.Service

* lint

* Parallelize validation only if class is CDN

* re-generate feature toggles

* remove waitgroup usage

* PR review: Add loader concurrency limit setting

* re-generate feature toggles

* pr review feedback

* fix const name

* Skip module.js validation for cdn plugins

* do not run validation steps in parallel

* lint

* reduce diff

* re-generate feature toggles

* lint

* pr review feedback

* remove leftover config.PluginManagementCfg from sources.Service

pkg/services/featuremgmt/registry.go

@@ -1794,6 +1794,12 @@ var (
 			HideFromDocs:      true,
 			RequiresRestart:   true,
 		},
+		{
+			Name:        "pluginsCDNSyncLoader",
+			Description: "Load plugins from CDN synchronously",
+			Stage:       FeatureStageExperimental,
+			Owner:       grafanaPluginsPlatformSquad,
+		},
 	}
 )
 

pkg/services/featuremgmt/toggles_gen.csv

@@ -238,3 +238,4 @@ alertingAlertmanagerExtraDedupStage,experimental,@grafana/alerting-squad,false,t
 alertingAlertmanagerExtraDedupStageStopPipeline,experimental,@grafana/alerting-squad,false,true,false
 newLogsPanel,experimental,@grafana/observability-logs,false,false,true
 grafanaconThemes,experimental,@grafana/grafana-frontend-platform,false,true,false
+pluginsCDNSyncLoader,experimental,@grafana/plugins-platform-backend,false,false,false

pkg/services/featuremgmt/toggles_gen.go

@@ -962,4 +962,8 @@ const (
 	// FlagGrafanaconThemes
 	// Enables the temporary themes for GrafanaCon
 	FlagGrafanaconThemes = "grafanaconThemes"
+
+	// FlagPluginsCDNSyncLoader
+	// Load plugins from CDN synchronously
+	FlagPluginsCDNSyncLoader = "pluginsCDNSyncLoader"
 )

pkg/services/featuremgmt/toggles_gen.json

@@ -3034,6 +3034,18 @@
         "frontend": true
       }
     },
+    {
+      "metadata": {
+        "name": "pluginsCDNSyncLoader",
+        "resourceVersion": "1737026684018",
+        "creationTimestamp": "2025-01-16T11:24:44Z"
+      },
+      "spec": {
+        "description": "Load plugins from CDN synchronously",
+        "stage": "experimental",
+        "codeowner": "@grafana/plugins-platform-backend"
+      }
+    },
     {
       "metadata": {
         "name": "pluginsDetailsRightPanel",