feat(cli): Support Server-Side Diff CLI

cmd/argocd/commands/app.go

@@ -39,9 +39,13 @@ import (
 	"github.com/argoproj/argo-cd/v3/cmd/argocd/commands/headless"
 	"github.com/argoproj/argo-cd/v3/cmd/argocd/commands/utils"
 	cmdutil "github.com/argoproj/argo-cd/v3/cmd/util"
+	argocommon "github.com/argoproj/argo-cd/v3/common"
 	"github.com/argoproj/argo-cd/v3/controller"
 	argocdclient "github.com/argoproj/argo-cd/v3/pkg/apiclient"
 	"github.com/argoproj/argo-cd/v3/pkg/apiclient/application"
+
+	resourceutil "github.com/argoproj/gitops-engine/pkg/sync/resource"
+
 	clusterpkg "github.com/argoproj/argo-cd/v3/pkg/apiclient/cluster"
 	projectpkg "github.com/argoproj/argo-cd/v3/pkg/apiclient/project"
 	"github.com/argoproj/argo-cd/v3/pkg/apiclient/settings"
@@ -1281,6 +1285,7 @@ func NewApplicationDiffCommand(clientOpts *argocdclient.ClientOptions) *cobra.Co
 		revision             string
 		localRepoRoot        string
 		serverSideGenerate   bool
+		serverSideDiff       bool
 		localIncludes        []string
 		appNamespace         string
 		revisions            []string
@@ -1343,6 +1348,22 @@ func NewApplicationDiffCommand(clientOpts *argocdclient.ClientOptions) *cobra.Co
 			argoSettings, err := settingsIf.Get(ctx, &settings.SettingsQuery{})
 			errors.CheckError(err)
 			diffOption := &DifferenceOption{}
+
+			hasServerSideDiffAnnotation := resourceutil.HasAnnotationOption(app, argocommon.AnnotationCompareOptions, "ServerSideDiff=true")
+
+			// Use annotation if flag not explicitly set
+			if !c.Flags().Changed("server-side-diff") {
+				serverSideDiff = hasServerSideDiffAnnotation
+			} else if serverSideDiff && !hasServerSideDiffAnnotation {
+				// Flag explicitly set to true, but app annotation is not set
+				fmt.Fprintf(os.Stderr, "Warning: Application does not have ServerSideDiff=true annotation.\n")
+			}
+
+			// Server side diff with local requires server side generate to be set as there will be a mismatch with client-generated manifests.
+			if serverSideDiff && local != "" && !serverSideGenerate {
+				log.Fatal("--server-side-diff with --local requires --server-side-generate.")
+			}
+
 			switch {
 			case app.Spec.HasMultipleSources() && len(revisions) > 0 && len(sourcePositions) > 0:
 				numOfSources := int64(len(app.Spec.GetSources()))
@@ -1398,7 +1419,8 @@ func NewApplicationDiffCommand(clientOpts *argocdclient.ClientOptions) *cobra.Co
 				}
 			}
 			proj := getProject(ctx, c, clientOpts, app.Spec.Project)
-			foundDiffs := findandPrintDiff(ctx, app, proj.Project, resources, argoSettings, diffOption, ignoreNormalizerOpts)
+
+			foundDiffs := findAndPrintDiff(ctx, app, proj.Project, resources, argoSettings, diffOption, ignoreNormalizerOpts, serverSideDiff, appIf, app.GetName(), app.GetNamespace())
 			if foundDiffs && exitCode {
 				os.Exit(diffExitCode)
 			}
@@ -1412,6 +1434,7 @@ func NewApplicationDiffCommand(clientOpts *argocdclient.ClientOptions) *cobra.Co
 	command.Flags().StringVar(&revision, "revision", "", "Compare live app to a particular revision")
 	command.Flags().StringVar(&localRepoRoot, "local-repo-root", "/", "Path to the repository root. Used together with --local allows setting the repository root")
 	command.Flags().BoolVar(&serverSideGenerate, "server-side-generate", false, "Used with --local, this will send your manifests to the server for diffing")
+	command.Flags().BoolVar(&serverSideDiff, "server-side-diff", false, "Use server-side diff to calculate the diff. This will default to true if the ServerSideDiff annotation is set on the application.")
 	command.Flags().StringArrayVar(&localIncludes, "local-include", []string{"*.yaml", "*.yml", "*.json"}, "Used with --server-side-generate, specify patterns of filenames to send. Matching is based on filename and not path.")
 	command.Flags().StringVarP(&appNamespace, "app-namespace", "N", "", "Only render the difference in namespace")
 	command.Flags().StringArrayVar(&revisions, "revisions", []string{}, "Show manifests at specific revisions for source position in source-positions")
@@ -1421,6 +1444,101 @@ func NewApplicationDiffCommand(clientOpts *argocdclient.ClientOptions) *cobra.Co
 	return command
 }
 
+// printResourceDiff prints the diff header and calls cli.PrintDiff for a resource
+func printResourceDiff(group, kind, namespace, name string, live, target *unstructured.Unstructured) {
+	fmt.Printf("\n===== %s/%s %s/%s ======\n", group, kind, namespace, name)
+	_ = cli.PrintDiff(name, live, target)
+}
+
+// findAndPrintServerSideDiff performs a server-side diff by making requests to the api server and prints the response
+func findAndPrintServerSideDiff(ctx context.Context, app *argoappv1.Application, items []objKeyLiveTarget, resources *application.ManagedResourcesResponse, appIf application.ApplicationServiceClient, appName, appNs string) bool {
+	// Process each item for server-side diff
+	foundDiffs := false
+	for _, item := range items {
+		if item.target != nil && hook.IsHook(item.target) || item.live != nil && hook.IsHook(item.live) {
+			continue
+		}
+
+		// For server-side diff, we need to create aligned arrays for this specific resource
+		var liveResource *argoappv1.ResourceDiff
+		var targetManifest string
+
+		if item.live != nil {
+			for _, res := range resources.Items {
+				if res.Group == item.key.Group && res.Kind == item.key.Kind &&
+					res.Namespace == item.key.Namespace && res.Name == item.key.Name {
+					liveResource = res
+					break
+				}
+			}
+		}
+
+		if liveResource == nil {
+			// Create empty live resource for creation case
+			liveResource = &argoappv1.ResourceDiff{
+				Group:       item.key.Group,
+				Kind:        item.key.Kind,
+				Namespace:   item.key.Namespace,
+				Name:        item.key.Name,
+				LiveState:   "",
+				TargetState: "",
+				Modified:    true,
+			}
+		}
+
+		if item.target != nil {
+			jsonBytes, err := json.Marshal(item.target)
+			if err != nil {
+				errors.CheckError(fmt.Errorf("error marshaling target object: %w", err))
+			}
+			targetManifest = string(jsonBytes)
+		}
+
+		// Call server-side diff for this individual resource
+		serverSideDiffQuery := &application.ApplicationServerSideDiffQuery{
+			AppName:         &appName,
+			AppNamespace:    &appNs,
+			Project:         &app.Spec.Project,
+			LiveResources:   []*argoappv1.ResourceDiff{liveResource},
+			TargetManifests: []string{targetManifest},
+		}
+
+		serverSideDiffRes, err := appIf.ServerSideDiff(ctx, serverSideDiffQuery)
+		if err != nil {
+			errors.CheckError(err)
+		}
+
+		// Extract diff for this resource
+		for _, resultItem := range serverSideDiffRes.Items {
+			if resultItem.Hook || (!resultItem.Modified && resultItem.TargetState != "" && resultItem.LiveState != "") {
+				continue
+			}
+
+			if resultItem.Modified || resultItem.TargetState == "" || resultItem.LiveState == "" {
+				var live, target *unstructured.Unstructured
+
+				if resultItem.TargetState != "" && resultItem.TargetState != "null" {
+					target = &unstructured.Unstructured{}
+					err = json.Unmarshal([]byte(resultItem.TargetState), target)
+					errors.CheckError(err)
+				}
+
+				if resultItem.LiveState != "" && resultItem.LiveState != "null" {
+					live = &unstructured.Unstructured{}
+					err = json.Unmarshal([]byte(resultItem.LiveState), live)
+					errors.CheckError(err)
+				}
+
+				// Print resulting diff for this resource
+				foundDiffs = true
+				printResourceDiff(resultItem.Group, resultItem.Kind, resultItem.Namespace, resultItem.Name, live, target)
+			}
+		}
+	}
+
+	return foundDiffs
+}
+
 // DifferenceOption struct to store diff options
 type DifferenceOption struct {
 	local         string
@@ -1432,47 +1550,15 @@ type DifferenceOption struct {
 	revisions     []string
 }
 
-// findandPrintDiff ... Prints difference between application current state and state stored in git or locally, returns boolean as true if difference is found else returns false
-func findandPrintDiff(ctx context.Context, app *argoappv1.Application, proj *argoappv1.AppProject, resources *application.ManagedResourcesResponse, argoSettings *settings.Settings, diffOptions *DifferenceOption, ignoreNormalizerOpts normalizers.IgnoreNormalizerOpts) bool {
+// findAndPrintDiff ... Prints difference between application current state and state stored in git or locally, returns boolean as true if difference is found else returns false
+func findAndPrintDiff(ctx context.Context, app *argoappv1.Application, proj *argoappv1.AppProject, resources *application.ManagedResourcesResponse, argoSettings *settings.Settings, diffOptions *DifferenceOption, ignoreNormalizerOpts normalizers.IgnoreNormalizerOpts, useServerSideDiff bool, appIf application.ApplicationServiceClient, appName, appNs string) bool {
 	var foundDiffs bool
-	liveObjs, err := cmdutil.LiveObjects(resources.Items)
-	errors.CheckError(err)
-	items := make([]objKeyLiveTarget, 0)
-	switch {
-	case diffOptions.local != "":
-		localObjs := groupObjsByKey(getLocalObjects(ctx, app, proj, diffOptions.local, diffOptions.localRepoRoot, argoSettings.AppLabelKey, diffOptions.cluster.Info.ServerVersion, diffOptions.cluster.Info.APIVersions, argoSettings.KustomizeOptions, argoSettings.TrackingMethod), liveObjs, app.Spec.Destination.Namespace)
-		items = groupObjsForDiff(resources, localObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace), app.Spec.Destination.Namespace)
-	case diffOptions.revision != "" || len(diffOptions.revisions) > 0:
-		var unstructureds []*unstructured.Unstructured
-		for _, mfst := range diffOptions.res.Manifests {
-			obj, err := argoappv1.UnmarshalToUnstructured(mfst)
-			errors.CheckError(err)
-			unstructureds = append(unstructureds, obj)
-		}
-		groupedObjs := groupObjsByKey(unstructureds, liveObjs, app.Spec.Destination.Namespace)
-		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace), app.Spec.Destination.Namespace)
-	case diffOptions.serversideRes != nil:
-		var unstructureds []*unstructured.Unstructured
-		for _, mfst := range diffOptions.serversideRes.Manifests {
-			obj, err := argoappv1.UnmarshalToUnstructured(mfst)
-			errors.CheckError(err)
-			unstructureds = append(unstructureds, obj)
-		}
-		groupedObjs := groupObjsByKey(unstructureds, liveObjs, app.Spec.Destination.Namespace)
-		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace), app.Spec.Destination.Namespace)
-	default:
-		for i := range resources.Items {
-			res := resources.Items[i]
-			live := &unstructured.Unstructured{}
-			err := json.Unmarshal([]byte(res.NormalizedLiveState), &live)
-			errors.CheckError(err)
 
-			target := &unstructured.Unstructured{}
-			err = json.Unmarshal([]byte(res.TargetState), &target)
-			errors.CheckError(err)
+	items, err := prepareObjectsForDiff(ctx, app, proj, resources, argoSettings, diffOptions)
+	errors.CheckError(err)
 
-			items = append(items, objKeyLiveTarget{kube.NewResourceKey(res.Group, res.Kind, res.Namespace, res.Name), live, target})
-		}
+	if useServerSideDiff {
+		return findAndPrintServerSideDiff(ctx, app, items, resources, appIf, appName, appNs)
 	}
 
 	for _, item := range items {
@@ -1499,7 +1585,6 @@ func findandPrintDiff(ctx context.Context, app *argoappv1.Application, proj *arg
 		errors.CheckError(err)
 
 		if diffRes.Modified || item.target == nil || item.live == nil {
-			fmt.Printf("\n===== %s/%s %s/%s ======\n", item.key.Group, item.key.Kind, item.key.Namespace, item.key.Name)
 			var live *unstructured.Unstructured
 			var target *unstructured.Unstructured
 			if item.target != nil && item.live != nil {
@@ -1511,10 +1596,8 @@ func findandPrintDiff(ctx context.Context, app *argoappv1.Application, proj *arg
 				live = item.live
 				target = item.target
 			}
-			if !foundDiffs {
-				foundDiffs = true
-			}
-			_ = cli.PrintDiff(item.key.Name, live, target)
+			foundDiffs = true
+			printResourceDiff(item.key.Group, item.key.Kind, item.key.Namespace, item.key.Name, live, target)
 		}
 	}
 	return foundDiffs
@@ -2296,7 +2379,11 @@ func NewApplicationSyncCommand(clientOpts *argocdclient.ClientOptions) *cobra.Co
 					fmt.Printf("====== Previewing differences between live and desired state of application %s ======\n", appQualifiedName)
 
 					proj := getProject(ctx, c, clientOpts, app.Spec.Project)
-					foundDiffs = findandPrintDiff(ctx, app, proj.Project, resources, argoSettings, diffOption, ignoreNormalizerOpts)
+
+					// Check if application has ServerSideDiff annotation
+					serverSideDiff := resourceutil.HasAnnotationOption(app, argocommon.AnnotationCompareOptions, "ServerSideDiff=true")
+
+					foundDiffs = findAndPrintDiff(ctx, app, proj.Project, resources, argoSettings, diffOption, ignoreNormalizerOpts, serverSideDiff, appIf, appName, appNs)
 					if !foundDiffs {
 						fmt.Printf("====== No Differences found ======\n")
 						// if no differences found, then no need to sync
@@ -3519,3 +3606,60 @@ func NewApplicationConfirmDeletionCommand(clientOpts *argocdclient.ClientOptions
 	command.Flags().StringVarP(&appNamespace, "app-namespace", "N", "", "Namespace of the target application where the source will be appended")
 	return command
 }
+
+// prepareObjectsForDiff prepares objects for diffing using the switch statement
+// to handle different diff options and building the objKeyLiveTarget items
+func prepareObjectsForDiff(ctx context.Context, app *argoappv1.Application, proj *argoappv1.AppProject, resources *application.ManagedResourcesResponse, argoSettings *settings.Settings, diffOptions *DifferenceOption) ([]objKeyLiveTarget, error) {
+	liveObjs, err := cmdutil.LiveObjects(resources.Items)
+	if err != nil {
+		return nil, err
+	}
+	items := make([]objKeyLiveTarget, 0)
+
+	switch {
+	case diffOptions.local != "":
+		localObjs := groupObjsByKey(getLocalObjects(ctx, app, proj, diffOptions.local, diffOptions.localRepoRoot, argoSettings.AppLabelKey, diffOptions.cluster.Info.ServerVersion, diffOptions.cluster.Info.APIVersions, argoSettings.KustomizeOptions, argoSettings.TrackingMethod), liveObjs, app.Spec.Destination.Namespace)
+		items = groupObjsForDiff(resources, localObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace), app.Spec.Destination.Namespace)
+	case diffOptions.revision != "" || len(diffOptions.revisions) > 0:
+		var unstructureds []*unstructured.Unstructured
+		for _, mfst := range diffOptions.res.Manifests {
+			obj, err := argoappv1.UnmarshalToUnstructured(mfst)
+			if err != nil {
+				return nil, err
+			}
+			unstructureds = append(unstructureds, obj)
+		}
+		groupedObjs := groupObjsByKey(unstructureds, liveObjs, app.Spec.Destination.Namespace)
+		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace), app.Spec.Destination.Namespace)
+	case diffOptions.serversideRes != nil:
+		var unstructureds []*unstructured.Unstructured
+		for _, mfst := range diffOptions.serversideRes.Manifests {
+			obj, err := argoappv1.UnmarshalToUnstructured(mfst)
+			if err != nil {
+				return nil, err
+			}
+			unstructureds = append(unstructureds, obj)
+		}
+		groupedObjs := groupObjsByKey(unstructureds, liveObjs, app.Spec.Destination.Namespace)
+		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace), app.Spec.Destination.Namespace)
+	default:
+		for i := range resources.Items {
+			res := resources.Items[i]
+			live := &unstructured.Unstructured{}
+			err := json.Unmarshal([]byte(res.NormalizedLiveState), &live)
+			if err != nil {
+				return nil, err
+			}
+
+			target := &unstructured.Unstructured{}
+			err = json.Unmarshal([]byte(res.TargetState), &target)
+			if err != nil {
+				return nil, err
+			}
+
+			items = append(items, objKeyLiveTarget{kube.NewResourceKey(res.Group, res.Kind, res.Namespace, res.Name), live, target})
+		}
+	}
+
+	return items, nil
+}