runtime: add util func for creating rest mapper

Add a new util func `NewDynamicRESTMapper(restConfig *rest.Config)` in
`runtime/client` for creating new RESTMapper objects.

Signed-off-by: Sanskar Jaiswal <jaiswalsanskar078@gmail.com>

runtime/client/client.go

@@ -20,9 +20,11 @@ import (
 	"context"
 
 	"github.com/spf13/pflag"
+	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/client-go/rest"
 	"sigs.k8s.io/cli-utils/pkg/flowcontrol"
 	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
 )
 
 const (
@@ -82,3 +84,19 @@ func GetConfigOrDie(opts Options) *rest.Config {
 	config.Burst = opts.Burst
 	return config
 }
+
+// NewDynamicRESTMapper creates a new HTTP client using the provided config.
+// It then returns a dynamic RESTMapper created using the HTTP client and
+// the config. The returned RESTMapper dynamically discovers resource types
+// at runtime.
+func NewDynamicRESTMapper(restConfig *rest.Config) (meta.RESTMapper, error) {
+	httpClient, err := rest.HTTPClientFor(restConfig)
+	if err != nil {
+		return nil, err
+	}
+	restMapper, err := apiutil.NewDynamicRESTMapper(restConfig, httpClient)
+	if err != nil {
+		return nil, err
+	}
+	return restMapper, nil
+}

runtime/client/impersonator.go

@@ -28,7 +28,6 @@ import (
 	"k8s.io/client-go/tools/clientcmd"
 	"sigs.k8s.io/cli-utils/pkg/kstatus/polling"
 	rc "sigs.k8s.io/controller-runtime/pkg/client"
-	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
 	"sigs.k8s.io/controller-runtime/pkg/client/config"
 
 	"github.com/fluxcd/pkg/apis/meta"
@@ -132,11 +131,7 @@ func (i *Impersonator) clientForServiceAccountOrDefault() (rc.Client, *polling.S
 	}
 	i.setImpersonationConfig(restConfig)
 
-	httpClient, err := rest.HTTPClientFor(restConfig)
-	if err != nil {
-		return nil, nil, err
-	}
-	restMapper, err := apiutil.NewDynamicRESTMapper(restConfig, httpClient)
+	restMapper, err := NewDynamicRESTMapper(restConfig)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -168,11 +163,7 @@ func (i *Impersonator) clientForKubeConfig(ctx context.Context) (rc.Client, *pol
 	restConfig = KubeConfig(restConfig, i.kubeConfigOpts)
 	i.setImpersonationConfig(restConfig)
 
-	httpClient, err := rest.HTTPClientFor(restConfig)
-	if err != nil {
-		return nil, nil, err
-	}
-	restMapper, err := apiutil.NewDynamicRESTMapper(restConfig, httpClient)
+	restMapper, err := NewDynamicRESTMapper(restConfig)
 	if err != nil {
 		return nil, nil, err
 	}