Add error options for rendering to return errors on failure (#48864)

pkg/services/rendering/interface.go

@@ -41,6 +41,7 @@ func getRequestTimeout(opt TimeoutOpts) time.Duration {
 type Opts struct {
 	TimeoutOpts
 	AuthOpts
+	ErrorOpts
 	Width             int
 	Height            int
 	Path              string
@@ -52,6 +53,15 @@ type Opts struct {
 	Theme             models.Theme
 }
 
+type ErrorOpts struct {
+	// ErrorConcurrentLimitReached returns an ErrConcurrentLimitReached
+	// error instead of a rendering limit exceeded image.
+	ErrorConcurrentLimitReached bool
+	// ErrorRenderUnavailable returns an ErrRunderUnavailable error
+	// instead of a rendering unavailable image.
+	ErrorRenderUnavailable bool
+}
+
 type CSVOpts struct {
 	TimeoutOpts
 	AuthOpts

pkg/services/rendering/rendering.go

@@ -235,6 +235,9 @@ func (rs *RenderingService) Render(ctx context.Context, opts Opts, session Sessi
 func (rs *RenderingService) render(ctx context.Context, opts Opts, renderKeyProvider renderKeyProvider) (*RenderResult, error) {
 	if int(atomic.LoadInt32(&rs.inProgressCount)) > opts.ConcurrentLimit {
 		rs.log.Warn("Could not render image, hit the currency limit", "concurrencyLimit", opts.ConcurrentLimit, "path", opts.Path)
+		if opts.ErrorConcurrentLimitReached {
+			return nil, ErrConcurrentLimitReached
+		}
 
 		theme := models.ThemeDark
 		if opts.Theme != "" {
@@ -250,6 +253,9 @@ func (rs *RenderingService) render(ctx context.Context, opts Opts, renderKeyProv
 		rs.log.Warn("Could not render image, no image renderer found/installed. " +
 			"For image rendering support please install the grafana-image-renderer plugin. " +
 			"Read more at https://grafana.com/docs/grafana/latest/administration/image_rendering/")
+		if opts.ErrorRenderUnavailable {
+			return nil, ErrRenderUnavailable
+		}
 		return rs.renderUnavailableImage(), nil
 	}
 

pkg/services/rendering/rendering_test.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/plugins"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -102,6 +103,22 @@ func TestRenderErrorImage(t *testing.T) {
 	})
 }
 
+type unavailableRendererManager struct{}
+
+func (m unavailableRendererManager) Renderer() *plugins.Plugin { return nil }
+
+func TestRenderUnavailableError(t *testing.T) {
+	rs := RenderingService{
+		Cfg:                   &setting.Cfg{},
+		log:                   log.New("test"),
+		RendererPluginManager: unavailableRendererManager{},
+	}
+	opts := Opts{ErrorOpts: ErrorOpts{ErrorRenderUnavailable: true}}
+	result, err := rs.Render(context.Background(), opts, nil)
+	assert.Equal(t, ErrRenderUnavailable, err)
+	assert.Nil(t, result)
+}
+
 func TestRenderLimitImage(t *testing.T) {
 	path, err := filepath.Abs("../../../")
 	require.NoError(t, err)
@@ -146,6 +163,22 @@ func TestRenderLimitImage(t *testing.T) {
 	}
 }
 
+func TestRenderLimitImageError(t *testing.T) {
+	rs := RenderingService{
+		Cfg:             &setting.Cfg{},
+		inProgressCount: 2,
+		log:             log.New("test"),
+	}
+	opts := Opts{
+		ErrorOpts:       ErrorOpts{ErrorConcurrentLimitReached: true},
+		ConcurrentLimit: 1,
+		Theme:           models.ThemeDark,
+	}
+	result, err := rs.Render(context.Background(), opts, nil)
+	assert.Equal(t, ErrConcurrentLimitReached, err)
+	assert.Nil(t, result)
+}
+
 func TestRenderingServiceGetRemotePluginVersion(t *testing.T) {
 	cfg := setting.NewCfg()
 	rs := &RenderingService{