Expressions: Add option to disable feature (#30541)

* Expressions: Add option to disable feature

* Apply suggestions from code review

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

conf/defaults.ini

@@ -893,3 +893,7 @@ use_browser_locale = false
 
 # Default timezone for user preferences. Options are 'browser' for the browser local timezone or a timezone name from IANA Time Zone database, e.g. 'UTC' or 'Europe/Amsterdam' etc.
 default_timezone = browser
+
+[expressions]
+# Disable expressions & UI features
+enabled = true

conf/sample.ini

@@ -883,3 +883,7 @@
 
 # Default timezone for user preferences. Options are 'browser' for the browser local timezone or a timezone name from IANA Time Zone database, e.g. 'UTC' or 'Europe/Amsterdam' etc.
 ;default_timezone = browser
+
+[expressions]
+# Disable expressions & UI features
+;enabled = true

docs/sources/administration/configuration.md

@@ -1505,3 +1505,8 @@ Set this to `true` to have date formats automatically derived from your browser
 ### default_timezone
 
 Used as the default time zone for user preferences. Can be either `browser` for the browser local time zone or a time zone name from the IANA Time Zone database, such as `UTC` or `Europe/Amsterdam`.
+
+## [expressions]
+>Note: This is available in Grafana v7.4 and later versions.
+### enabled
+Set this to `false` to disable expressions and hide them in the Grafana UI. Default is `true`.

packages/grafana-runtime/src/config.ts

@@ -68,6 +68,7 @@ export class GrafanaBootConfig implements GrafanaConfig {
     sampleRate: 1,
   };
   marketplaceUrl?: string;
+  expressionsEnabled = false;
 
   constructor(options: GrafanaBootConfig) {
     this.theme = options.bootData.user.lightTheme ? getTheme(GrafanaThemeType.Light) : getTheme(GrafanaThemeType.Dark);

pkg/api/frontendsettings.go

@@ -237,11 +237,12 @@ func (hs *HTTPServer) getFrontendSettingsMap(c *models.ReqContext) (map[string]i
 			"licenseUrl":      hs.License.LicenseURL(c.SignedInUser),
 			"edition":         hs.License.Edition(),
 		},
-		"featureToggles":    hs.Cfg.FeatureToggles,
-		"rendererAvailable": hs.RenderService.IsAvailable(),
-		"http2Enabled":      hs.Cfg.Protocol == setting.HTTP2Scheme,
-		"sentry":            hs.Cfg.Sentry,
-		"marketplaceUrl":    hs.Cfg.MarketplaceURL,
+		"featureToggles":     hs.Cfg.FeatureToggles,
+		"rendererAvailable":  hs.RenderService.IsAvailable(),
+		"http2Enabled":       hs.Cfg.Protocol == setting.HTTP2Scheme,
+		"sentry":             hs.Cfg.Sentry,
+		"marketplaceUrl":     hs.Cfg.MarketplaceURL,
+		"expressionsEnabled": hs.Cfg.ExpressionsEnabled,
 	}
 
 	return jsonObj, nil

pkg/api/metrics.go

@@ -121,7 +121,8 @@ func (hs *HTTPServer) handleExpressions(c *models.ReqContext, reqDTO dtos.Metric
 		})
 	}
 
-	resp, err := expr.WrapTransformData(c.Req.Context(), request)
+	exprService := expr.Service{Cfg: hs.Cfg}
+	resp, err := exprService.WrapTransformData(c.Req.Context(), request)
 	if err != nil {
 		return response.Error(500, "expression request error", err)
 	}

pkg/expr/service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/grafana/grafana/pkg/setting"
 )
 
 // DatasourceName is the string constant used as the datasource name in requests
@@ -20,6 +21,14 @@ const DatasourceUID = "-100"
 
 // Service is service representation for expression handling.
 type Service struct {
+	Cfg *setting.Cfg
+}
+
+func (s *Service) isDisabled() bool {
+	if s.Cfg == nil {
+		return true
+	}
+	return !s.Cfg.ExpressionsEnabled
 }
 
 // BuildPipeline builds a pipeline from a request.

pkg/expr/transform.go

@@ -16,7 +16,7 @@ import (
 	"google.golang.org/grpc/status"
 )
 
-func WrapTransformData(ctx context.Context, query *tsdb.TsdbQuery) (*tsdb.Response, error) {
+func (s *Service) WrapTransformData(ctx context.Context, query *tsdb.TsdbQuery) (*tsdb.Response, error) {
 	sdkReq := &backend.QueryDataRequest{
 		PluginContext: backend.PluginContext{
 			OrgID: query.User.OrgId,
@@ -41,7 +41,7 @@ func WrapTransformData(ctx context.Context, query *tsdb.TsdbQuery) (*tsdb.Respon
 			},
 		})
 	}
-	pbRes, err := TransformData(ctx, sdkReq)
+	pbRes, err := s.TransformData(ctx, sdkReq)
 	if err != nil {
 		return nil, err
 	}
@@ -69,17 +69,20 @@ func WrapTransformData(ctx context.Context, query *tsdb.TsdbQuery) (*tsdb.Respon
 
 // TransformData takes Queries which are either expressions nodes
 // or are datasource requests.
-func TransformData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
-	svc := Service{}
+func (s *Service) TransformData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
+	if s.isDisabled() {
+		return nil, status.Error(codes.PermissionDenied, "Expressions are disabled")
+	}
+
 	// Build the pipeline from the request, checking for ordering issues (e.g. loops)
 	// and parsing graph nodes from the queries.
-	pipeline, err := svc.BuildPipeline(req)
+	pipeline, err := s.BuildPipeline(req)
 	if err != nil {
 		return nil, status.Error(codes.InvalidArgument, err.Error())
 	}
 
 	// Execute the pipeline
-	responses, err := svc.ExecutePipeline(ctx, pipeline)
+	responses, err := s.ExecutePipeline(ctx, pipeline)
 	if err != nil {
 		return nil, status.Error(codes.Unknown, err.Error())
 	}

pkg/services/ngalert/api.go

@@ -39,7 +39,8 @@ func (ng *AlertNG) conditionEvalEndpoint(c *models.ReqContext, dto evalAlertCond
 		return response.Error(400, "invalid condition", err)
 	}
 
-	evalResults, err := eval.ConditionEval(&dto.Condition, timeNow())
+	evaluator := eval.Evaluator{Cfg: ng.Cfg}
+	evalResults, err := evaluator.ConditionEval(&dto.Condition, timeNow())
 	if err != nil {
 		return response.Error(400, "Failed to evaluate conditions", err)
 	}
@@ -69,7 +70,8 @@ func (ng *AlertNG) alertDefinitionEvalEndpoint(c *models.ReqContext) response.Re
 		return response.Error(400, "invalid condition", err)
 	}
 
-	evalResults, err := eval.ConditionEval(condition, timeNow())
+	evaluator := eval.Evaluator{Cfg: ng.Cfg}
+	evalResults, err := evaluator.ConditionEval(condition, timeNow())
 	if err != nil {
 		return response.Error(400, "Failed to evaluate alert", err)
 	}

pkg/services/ngalert/eval/eval.go

@@ -7,6 +7,8 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/grafana/grafana/pkg/setting"
+
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/data"
 	"github.com/grafana/grafana/pkg/expr"
@@ -14,6 +16,10 @@ import (
 
 const alertingEvaluationTimeout = 30 * time.Second
 
+type Evaluator struct {
+	Cfg *setting.Cfg
+}
+
 // invalidEvalResultFormatError is an error for invalid format of the alert definition evaluation results.
 type invalidEvalResultFormatError struct {
 	refID  string
@@ -87,7 +93,8 @@ func (c Condition) IsValid() bool {
 
 // AlertExecCtx is the context provided for executing an alert condition.
 type AlertExecCtx struct {
-	OrgID int64
+	OrgID              int64
+	ExpressionsEnabled bool
 
 	Ctx context.Context
 }
@@ -133,7 +140,8 @@ func (c *Condition) execute(ctx AlertExecCtx, now time.Time) (*ExecutionResults,
 		})
 	}
 
-	pbRes, err := expr.TransformData(ctx.Ctx, queryDataReq)
+	exprService := expr.Service{Cfg: &setting.Cfg{ExpressionsEnabled: ctx.ExpressionsEnabled}}
+	pbRes, err := exprService.TransformData(ctx.Ctx, queryDataReq)
 	if err != nil {
 		return &result, err
 	}
@@ -210,11 +218,11 @@ func (evalResults Results) AsDataFrame() data.Frame {
 }
 
 // ConditionEval executes conditions and evaluates the result.
-func ConditionEval(condition *Condition, now time.Time) (Results, error) {
+func (e *Evaluator) ConditionEval(condition *Condition, now time.Time) (Results, error) {
 	alertCtx, cancelFn := context.WithTimeout(context.Background(), alertingEvaluationTimeout)
 	defer cancelFn()
 
-	alertExecCtx := AlertExecCtx{OrgID: condition.OrgID, Ctx: alertCtx}
+	alertExecCtx := AlertExecCtx{OrgID: condition.OrgID, Ctx: alertCtx, ExpressionsEnabled: e.Cfg.ExpressionsEnabled}
 
 	execResult, err := condition.execute(alertExecCtx, now)
 	if err != nil {

pkg/services/ngalert/ngalert.go

@@ -47,7 +47,13 @@ func (ng *AlertNG) Init() error {
 	ng.log = log.New("ngalert")
 
 	ng.registerAPIEndpoints()
-	ng.schedule = newScheduler(clock.New(), baseIntervalSeconds*time.Second, ng.log, nil)
+	schedCfg := schedulerCfg{
+		c:            clock.New(),
+		baseInterval: baseIntervalSeconds * time.Second,
+		logger:       ng.log,
+		evaluator:    eval.Evaluator{Cfg: ng.Cfg},
+	}
+	ng.schedule = newScheduler(schedCfg)
 	return nil
 }
 

pkg/services/ngalert/schedule.go

@@ -47,7 +47,7 @@ func (ng *AlertNG) definitionRoutine(grafanaCtx context.Context, key alertDefini
 					OrgID:                 alertDefinition.OrgID,
 					QueriesAndExpressions: alertDefinition.Data,
 				}
-				results, err := eval.ConditionEval(&condition, ctx.now)
+				results, err := ng.schedule.evaluator.ConditionEval(&condition, ctx.now)
 				end = timeNow()
 				if err != nil {
 					// consider saving alert instance on error
@@ -118,19 +118,30 @@ type schedule struct {
 	stopApplied func(alertDefinitionKey)
 
 	log log.Logger
+
+	evaluator eval.Evaluator
+}
+
+type schedulerCfg struct {
+	c            clock.Clock
+	baseInterval time.Duration
+	logger       log.Logger
+	evalApplied  func(alertDefinitionKey, time.Time)
+	evaluator    eval.Evaluator
 }
 
 // newScheduler returns a new schedule.
-func newScheduler(c clock.Clock, baseInterval time.Duration, logger log.Logger, evalApplied func(alertDefinitionKey, time.Time)) *schedule {
-	ticker := alerting.NewTicker(c.Now(), time.Second*0, c, int64(baseInterval.Seconds()))
+func newScheduler(cfg schedulerCfg) *schedule {
+	ticker := alerting.NewTicker(cfg.c.Now(), time.Second*0, cfg.c, int64(cfg.baseInterval.Seconds()))
 	sch := schedule{
 		registry:     alertDefinitionRegistry{alertDefinitionInfo: make(map[alertDefinitionKey]alertDefinitionInfo)},
 		maxAttempts:  maxAttempts,
-		clock:        c,
-		baseInterval: baseInterval,
-		log:          logger,
+		clock:        cfg.c,
+		baseInterval: cfg.baseInterval,
+		log:          cfg.logger,
 		heartbeat:    ticker,
-		evalApplied:  evalApplied,
+		evalApplied:  cfg.evalApplied,
+		evaluator:    cfg.evaluator,
 	}
 	return &sch
 }

pkg/services/ngalert/schedule_test.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/registry"
+	"github.com/grafana/grafana/pkg/services/ngalert/eval"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -26,7 +27,13 @@ func TestAlertingTicker(t *testing.T) {
 	t.Cleanup(registry.ClearOverrides)
 
 	mockedClock := clock.NewMock()
-	ng.schedule = newScheduler(mockedClock, time.Second, log.New("ngalert.schedule.test"), nil)
+	schefCfg := schedulerCfg{
+		c:            mockedClock,
+		baseInterval: time.Second,
+		logger:       log.New("ngalert.schedule.test"),
+		evaluator:    eval.Evaluator{Cfg: ng.Cfg},
+	}
+	ng.schedule = newScheduler(schefCfg)
 
 	alerts := make([]*AlertDefinition, 0)
 

pkg/setting/setting.go

@@ -339,6 +339,9 @@ type Cfg struct {
 	AutoAssignOrg     bool
 	AutoAssignOrgId   int
 	AutoAssignOrgRole string
+
+	// ExpressionsEnabled specifies whether expressions are enabled.
+	ExpressionsEnabled bool
 }
 
 // IsLiveEnabled returns if grafana live should be enabled
@@ -482,6 +485,11 @@ func (cfg *Cfg) readAnnotationSettings() {
 	cfg.APIAnnotationCleanupSettings = newAnnotationCleanupSettings(apiIAnnotation, "max_age")
 }
 
+func (cfg *Cfg) readExpressionsSettings() {
+	expressions := cfg.Raw.Section("expressions")
+	cfg.ExpressionsEnabled = expressions.Key("enabled").MustBool(true)
+}
+
 type AnnotationCleanupSettings struct {
 	MaxAge   time.Duration
 	MaxCount int64
@@ -850,6 +858,7 @@ func (cfg *Cfg) Load(args *CommandLineArgs) error {
 	cfg.readSmtpSettings()
 	cfg.readQuotaSettings()
 	cfg.readAnnotationSettings()
+	cfg.readExpressionsSettings()
 	if err := cfg.readGrafanaEnvironmentMetrics(); err != nil {
 		return err
 	}

public/app/features/query/components/QueryGroup.tsx

@@ -315,7 +315,7 @@ export class QueryGroup extends PureComponent<Props, State> {
           </Button>
         )}
         {isAddingMixed && this.renderMixedPicker()}
-        {this.isExpressionsSupported(dsSettings) && (
+        {config.expressionsEnabled && this.isExpressionsSupported(dsSettings) && (
           <Tooltip content="Experimental feature: queries could stop working in next version" placement="right">
             <Button
               icon="plus"