Plugins: Allow loading panel plugins from a CDN (#59096)

* POC: Plugins CDN reverse proxy

* CDN proxy POC: changed env var names

* Add authorization: false for /public path in frontend plugin loader

* Moved CDN settings to Cfg, add some comments

* Fix error 500 in asset fetch if plugin is not using CDN

* Fix EnterpriseLicensePath declared twice

* Fix linter complaining about whitespaces

* Plugins CDN: Skip signature verification for CDN plugins

* Plugins CDN: Skip manifest and signature check for cdn plugins

* Plugins: use IsValid() and IsInternal() rather than equality checks

* Plugins CDN: remove comment

* Plugins CDN: Fix seeker can't seek when serving plugins from local fs

* Plugins CDN: add back error codes in getLocalPluginAssets

* Plugins CDN: call asset.Close() rather than asset.readSeekCloser.Close()

* Plugins CDN: Fix panic in JsonApiErr when errorMessageCoder wraps a nil error

* Plugins CDN: Add error handling to proxyCDNPluginAsset

* Plugins CDN: replace errorMessageCoder with errutil

* Plugins CDN POC: expose cdn plugin paths to frontend for system.js

* Plugins CDN: Fix cdn plugins showing as unsigned in frontend

* WIP: Add support for formatted URL

* Fix missing cdnPluginsBaseURLs in GrafanaConfig

* Plugins CDN: Remove reverse proxy mode and reverse proxy references

* Plugins CDN: Simplify asset serving logic

* Plugins CDN: sanitize redirect path

* Plugins CDN: Removed unused pluginAsset type

* Plugins CDN: Removed system.js changes

* Plugins CDN: Return different system.js baseURL and module for cdn plugins

* Plugins CDN: Ensure CDN is disabled for non-external plugins

* lint

* Plugins CDN: serve images and screenshots from CDN, refactoring

* Lint

* Plugins CDN: Fix URLs for system.js (baseUrl and module)

* Plugins CDN: Add more tests for RelativeURLForSystemJS

* Plugins CDN: Iterate only on apps when preloading

* Plugins CDN: Refactoring

* Plugins CDN: Add comments to url_constructor.go

* Plugins CDN: Update defaultHGPluginsCDNBaseURL

* Plugins CDN: undo extract meta from system js config

* refactor(plugins): migrate systemjs css plugin to typescript

* feat(plugins): introduce systemjs cdn loader plugin

* feat(plugins): add systemjs load type

* Plugins CDN: Removed RelativeURLForSystemJS

* Plugins CDN: Log backend redirect hits along with plugin info

* Plugins CDN: Add pluginsCDNBasePath to getFrontendSettingsMap

* feat(plugins): introduce cdn loading for angular plugins

* refactor(plugins): move systemjs cache buster into systemjsplugins directory

* Plugins CDN: Rename pluginsCDNBasePath to pluginsCDNBaseURL

* refactor(plugins): introduce pluginsCDNBaseURL to the frontend

* Plugins CDN: Renamed "cdn base path" to "cdn url template" in backend

* Plugins CDN: lint

* merge with main

* Instrumentation: Add prometheus counter for backend hits, log from Info to Warn

* Config: Changed key from plugins_cdn.url to plugins.plugins_cdn_base_url

* CDN: Add backend tests

* Lint: goimports

* Default CDN URL to empty string,

* Do not use CDN in setImages and module if the url template is empty

* CDN: Backend: Add test for frontend settings

* CDN: Do not log missing module.js warn if plugin is being loaded from CDN

* CDN: Add backend test for CDN plugin loader

* Removed 'cdn' signature level, switch to 'valid'

* Fix pfs.TestParseTreeTestdata for cdn plugin testdata dir

* Fix TestLoader_Load

* Fix gocyclo complexity of loadPlugins

* Plugins CDN: Moved prometheus metric to api package, removed asset_path label

* Fix missing  in config

* Changes after review

* Add pluginscdn.Service

* Fix tests

* Refactoring

* Moved all remaining CDN checks inside pluginscdn.Service

* CDN url constructor: Renamed stringURLFor to stringPath

* CDN: Moved asset URL functionality to assetpath service

* CDN: Renamed HasCDN() to IsEnabled()

* CDN: Replace assert with require

* CDN: Changes after review

* Assetpath: Handle url.Parse error

* Fix plugin_resource_test

* CDN: Change fallback redirect from 302 to 307

* goimports

* Fix tests

* Switch to contextmodel.ReqContext in plugins.go

Co-authored-by: Will Browne <will.browne@grafana.com>
Co-authored-by: Jack Westbrook <jack.westbrook@gmail.com>

pkg/api/frontendsettings_test.go

@@ -8,6 +8,8 @@ import (
 	"testing"
 
 	"github.com/grafana/grafana/pkg/login/social"
+	"github.com/grafana/grafana/pkg/plugins/config"
+	"github.com/grafana/grafana/pkg/plugins/pluginscdn"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -58,7 +60,11 @@ func setupTestEnvironment(t *testing.T, cfg *setting.Cfg, features *featuremgmt.
 		grafanaUpdateChecker: &updatechecker.GrafanaService{},
 		AccessControl:        accesscontrolmock.New().WithDisabled(),
 		PluginSettings:       pluginSettings.ProvideService(sqlStore, secretsService),
-		SocialService:        social.ProvideService(cfg, features),
+		pluginsCDNService: pluginscdn.ProvideService(&config.Cfg{
+			PluginsCDNURLTemplate: cfg.PluginsCDNURLTemplate,
+			PluginSettings:        cfg.PluginSettings,
+		}),
+		SocialService: social.ProvideService(cfg, features),
 	}
 
 	m := web.New()
@@ -138,3 +144,53 @@ func TestHTTPServer_GetFrontendSettings_hideVersionAnonymous(t *testing.T) {
 		})
 	}
 }
+
+func TestHTTPServer_GetFrontendSettings_pluginsCDNBaseURL(t *testing.T) {
+	type settings struct {
+		PluginsCDNBaseURL string `json:"pluginsCDNBaseURL"`
+	}
+
+	tests := []struct {
+		desc      string
+		mutateCfg func(*setting.Cfg)
+		expected  settings
+	}{
+		{
+			desc: "With CDN",
+			mutateCfg: func(cfg *setting.Cfg) {
+				cfg.PluginsCDNURLTemplate = "https://cdn.example.com/{id}/{version}/public/plugins/{id}/{assetPath}"
+			},
+			expected: settings{PluginsCDNBaseURL: "https://cdn.example.com"},
+		},
+		{
+			desc: "Without CDN",
+			mutateCfg: func(cfg *setting.Cfg) {
+				cfg.PluginsCDNURLTemplate = ""
+			},
+			expected: settings{PluginsCDNBaseURL: ""},
+		},
+		{
+			desc:     "CDN is disabled by default",
+			expected: settings{PluginsCDNBaseURL: ""},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.desc, func(t *testing.T) {
+			cfg := setting.NewCfg()
+			if test.mutateCfg != nil {
+				test.mutateCfg(cfg)
+			}
+			m, _ := setupTestEnvironment(t, cfg, featuremgmt.WithFeatures())
+			req := httptest.NewRequest(http.MethodGet, "/api/frontend/settings", nil)
+
+			recorder := httptest.NewRecorder()
+			m.ServeHTTP(recorder, req)
+			var got settings
+			err := json.Unmarshal(recorder.Body.Bytes(), &got)
+			require.NoError(t, err)
+			require.Equal(t, http.StatusOK, recorder.Code)
+			require.EqualValues(t, test.expected, got)
+		})
+	}
+}