apiserver-runtime-gen easier to use

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/spf13/cobra v1.1.3
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.7.0
+	golang.org/x/mod v0.4.2
 	k8s.io/api v0.21.2
 	k8s.io/apimachinery v0.21.2
 	k8s.io/apiserver v0.21.2

pkg/builder/doc.go

@@ -43,7 +43,7 @@ limitations under the License.
 // Install the code generators (from your module):
 //
 //    $ go get sigs.k8s.io/apiserver-runtime/tools/apiserver-runtime-gen
-//    $ apiserver-runtime-gen --install
+//    $ apiserver-runtime-gen --install-generators
 //
 // Add the code generation tag to you main package:
 //

tools/apiserver-runtime-gen/main.go

@@ -12,6 +12,7 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
+	"golang.org/x/mod/modfile"
 )
 
 var bin, output string
@@ -166,15 +167,11 @@ func main() {
 	cmd.Flags().BoolVar(&install, "install-generators", true, "Go get the generators")
 
 	var defaultModule string
-	why := exec.Command("go", "mod", "why")
-	why.Stderr = os.Stderr
-	if m, err := why.Output(); err == nil {
-		parts := strings.Split(string(m), "\n")
-		if len(parts) > 1 {
-			defaultModule = parts[1]
+	cwd, _ := os.Getwd()
+	if modRoot := findModuleRoot(cwd); modRoot != "" {
+		if b, err := ioutil.ReadFile(path.Join(modRoot, "go.mod")); err == nil {
+			defaultModule = modfile.ModulePath(b)
 		}
-	} else {
-		fmt.Fprintf(os.Stderr, "cannot parse go module: %v\n", err)
 	}
 	cmd.Flags().StringVar(&module, "module", defaultModule, "Go module of the apiserver.")
 
@@ -226,3 +223,18 @@ func getCmd(cmd string, args ...string) *exec.Cmd {
 	e.Args = append(e.Args, args...)
 	return e
 }
+
+func findModuleRoot(dir string) string {
+	for {
+		if _, err := os.Stat(filepath.Join(dir, "go.mod")); err == nil {
+			return dir
+		}
+
+		parentDIR := path.Dir(dir)
+		if parentDIR == dir {
+			break
+		}
+		dir = parentDIR
+	}
+	return ""
+}