Add indirection of ImexManager through wrapping Controller abstraction

In the future, we plan to manage multiple components from this wrapping
abstraction.

Signed-off-by: Kevin Klues <[email protected]>

Author: klueska

cmd/nvidia-dra-controller/controller.go

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2025 NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"context"
+	"fmt"
+)
+
+type Controller struct {
+	ImexManager *ImexManager
+}
+
+// StartController starts a Controller.
+func StartController(ctx context.Context, config *Config) (*Controller, error) {
+	if !config.flags.deviceClasses.Has(ImexChannelType) {
+		return nil, nil
+	}
+
+	imexManager, err := StartImexManager(ctx, config)
+	if err != nil {
+		return nil, fmt.Errorf("error starting IMEX manager: %w", err)
+	}
+
+	m := &Controller{
+		ImexManager: imexManager,
+	}
+
+	return m, nil
+}
+
+// Stop stops a running Controller.
+func (m *Controller) Stop() error {
+	if m == nil {
+		return nil
+	}
+	return m.ImexManager.Stop()
+}

cmd/nvidia-dra-controller/imex.go

@@ -64,7 +64,7 @@ type ImexManager struct {
 	driverResources               *resourceslice.DriverResources
 }
 
-func StartIMEXManager(ctx context.Context, config *Config) (*ImexManager, error) {
+func StartImexManager(ctx context.Context, config *Config) (*ImexManager, error) {
 	// Create a new set of DriverResources
 	driverResources := &resourceslice.DriverResources{
 		Pools: make(map[string]resourceslice.Pool),

cmd/nvidia-dra-controller/main.go

@@ -159,20 +159,18 @@ func newApp() *cli.App {
 			sigs := make(chan os.Signal, 1)
 			signal.Notify(sigs, syscall.SIGTERM, syscall.SIGINT)
 
-			var imexManager *ImexManager
+			var controller *Controller
 			ctx, cancel := context.WithCancel(c.Context)
 			defer func() {
 				cancel()
-				if err := imexManager.Stop(); err != nil {
-					klog.Errorf("Error stopping IMEX manager: %v", err)
+				if err := controller.Stop(); err != nil {
+					klog.Errorf("Error stopping controller: %v", err)
 				}
 			}()
 
-			if flags.deviceClasses.Has(ImexChannelType) {
-				imexManager, err = StartIMEXManager(ctx, config)
-				if err != nil {
-					return fmt.Errorf("start IMEX manager: %w", err)
-				}
+			controller, err = StartController(ctx, config)
+			if err != nil {
+				return fmt.Errorf("start controller: %w", err)
 			}
 
 			<-sigs