CI: move grabpl build-frontend from grabpl to grafana (#53073)

* move grabpl build-frontend

pkg/build/cmd/buildfrontend.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"log"
+	"strings"
+
+	"github.com/grafana/grafana/pkg/build/errutil"
+	"github.com/grafana/grafana/pkg/build/frontend"
+	"github.com/grafana/grafana/pkg/build/syncutil"
+	"github.com/urfave/cli/v2"
+)
+
+func BuildFrontend(c *cli.Context) error {
+	version := ""
+	if c.NArg() == 1 {
+		version = strings.TrimPrefix(c.Args().Get(0), "v")
+	}
+
+	cfg, mode, err := frontend.GetConfig(c, version)
+	if err != nil {
+		return err
+	}
+
+	p := syncutil.NewWorkerPool(cfg.NumWorkers)
+	defer p.Close()
+
+	g, _ := errutil.GroupWithContext(c.Context)
+	if err := frontend.Build(mode, frontend.GrafanaDir, p, g); err != nil {
+		return err
+	}
+	if err := g.Wait(); err != nil {
+		return err
+	}
+
+	log.Println("Successfully built Grafana front-end!")
+
+	return nil
+}

pkg/build/cmd/main.go

@@ -25,6 +25,17 @@ func main() {
 				&buildIDFlag,
 			},
 		},
+		{
+			Name:      "build-frontend",
+			Usage:     "Build front-end artifacts",
+			ArgsUsage: "[version]",
+			Action:    ArgCountWrapper(1, BuildFrontend),
+			Flags: []cli.Flag{
+				&jobsFlag,
+				&editionFlag,
+				&buildIDFlag,
+			},
+		},
 		{
 			Name:   "build-docker",
 			Usage:  "Build Grafana Docker images",