Allow dynamic client to be set

This allows us to override the dynamic client, useful for tests or if
we want to intercept and track all the calls (for automatic dependency
tracking).

Author: justinsb

pkg/patterns/declarative/pkg/applier/applylib.go

@@ -54,9 +54,13 @@ func (a *ApplySetApplier) Apply(ctx context.Context, opt ApplierOptions) error {
 
 	patchOptions.Force = &opt.Force
 
-	dynamicClient, err := dynamic.NewForConfig(opt.RESTConfig)
-	if err != nil {
-		return fmt.Errorf("error building dynamic client: %w", err)
+	dynamicClient := opt.DynamicClient
+	if dynamicClient == nil {
+		d, err := dynamic.NewForConfig(opt.RESTConfig)
+		if err != nil {
+			return fmt.Errorf("error building dynamic client: %w", err)
+		}
+		dynamicClient = d
 	}
 
 	restMapper := opt.RESTMapper

pkg/patterns/declarative/pkg/applier/type.go

@@ -5,6 +5,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/rest"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/kubebuilder-declarative-pattern/applylib/applyset"
@@ -39,4 +40,8 @@ type ApplierOptions struct {
 
 	ParentRef applyset.Parent
 	Client    client.Client
+
+	// DynamicClient, if set, will be used for applying additional objects.
+	// If not set, a dynamic client will be built from RESTConfig.
+	DynamicClient dynamic.Interface
 }