Codegen: format golang code from cue (#105352)

pkg/codegen/jenny_gofmt.go

@@ -0,0 +1,29 @@
+package codegen
+
+import (
+	"go/format"
+	"path/filepath"
+
+	"golang.org/x/tools/imports"
+
+	"github.com/grafana/codejen"
+)
+
+// GoFormat applies go format to each go file
+func GoFormat() codejen.FileMapper {
+	return func(f codejen.File) (codejen.File, error) {
+		if filepath.Ext(f.RelativePath) != ".go" {
+			return f, nil
+		}
+
+		formatted, err := format.Source(f.Data)
+		if err != nil {
+			return f, err
+		}
+
+		f.Data, err = imports.Process("", formatted, &imports.Options{
+			Comments: true,
+		})
+		return f, err
+	}
+}