Reporting: Handle timeouts in rendering (#20415)

* Added timeout in grpc call to plugins for rendering

pkg/services/rendering/rendering.go

@@ -3,12 +3,11 @@ package rendering
 import (
 	"context"
 	"fmt"
+	plugin "github.com/hashicorp/go-plugin"
 	"net/url"
 	"os"
 	"path/filepath"
 
-	plugin "github.com/hashicorp/go-plugin"
-
 	pluginModel "github.com/grafana/grafana-plugin-model/go/renderer"
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/middleware"
@@ -93,10 +92,20 @@ func (rs *RenderingService) Run(ctx context.Context) error {
 	return err
 }
 
+func (rs *RenderingService) RenderErrorImage(err error) (*RenderResult, error) {
+	imgUrl := "public/img/rendering_error.png"
+
+	return &RenderResult{
+		FilePath:            filepath.Join(setting.HomePath, imgUrl),
+		KeepFileAfterRender: true,
+	}, nil
+}
+
 func (rs *RenderingService) Render(ctx context.Context, opts Opts) (*RenderResult, error) {
 	if rs.inProgressCount > opts.ConcurrentLimit {
 		return &RenderResult{
-			FilePath: filepath.Join(setting.HomePath, "public/img/rendering_limit.png"),
+			FilePath:            filepath.Join(setting.HomePath, "public/img/rendering_limit.png"),
+			KeepFileAfterRender: true,
 		}, nil
 	}