Add flag for pretty-printing discovery JSON

internal/cmd/discoverworkload/discoverworkload.go

@@ -33,6 +33,7 @@ type config struct {
 	KubeconfigPath string
 	LabelSelector  string
 	FieldSelector  string
+	CompactOutput  bool
 }
 
 func NewCommand(ctx context.Context) *cobra.Command {
@@ -73,6 +74,10 @@ func NewCommand(ctx context.Context) *cobra.Command {
 			go discover.StartNotifier(ctx, logger, 15*time.Second, 30*time.Second)
 
 			logger.Info("starting to watch for workloads", "duration", cfg.Timeout)
+
+			opts := discover.NewManifestJSONProcessorFnOptions{
+				CompactOutput: cfg.CompactOutput,
+			}
 			err = discover.WatchForWorkloads(
 				ctx,
 				logger,
@@ -82,7 +87,7 @@ func NewCommand(ctx context.Context) *cobra.Command {
 					FieldSelector: cfg.FieldSelector,
 				},
 				k8sclient,
-				discover.NewManifestJSONProcessorFn(os.Stdout),
+				discover.NewManifestJSONProcessorFn(os.Stdout, opts),
 			)
 			if err != nil {
 				switch {
@@ -108,6 +113,7 @@ func NewCommand(ctx context.Context) *cobra.Command {
 	flags.StringVarP(&cfg.KubeconfigPath, "kubeconfig", "k", clientcmd.RecommendedHomeFile, "The kubeconfig to use for cluster access.")
 	flags.StringVarP(&cfg.LabelSelector, "selector", "l", "", "Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2). Matching objects must satisfy all of the specified label constraints.")
 	flags.StringVar(&cfg.FieldSelector, "field-selector", "", "Selector (field query) to filter on, supports '=', '==', and '!='.(e.g. --field-selector key1=value1,key2=value2). The server only supports a limited number of field queries per type.")
+	flags.BoolVarP(&cfg.CompactOutput, "compact", "c", false, "Print JSON in compact format instead of pretty-printed output")
 
 	return c
 }

internal/discover/processor.go

@@ -13,10 +13,14 @@ import (
 	"github.com/opdev/discover-workload/discovery"
 )
 
+type NewManifestJSONProcessorFnOptions struct {
+	CompactOutput bool
+}
+
 // NewManifestJSONProcessorFn produces a ProcessingFunction that will write a
 // Manifest in JSON to out. This Processor finds all images from containers,
 // initContainers, and ephemeralContainers.
-func NewManifestJSONProcessorFn(out io.Writer) ProcessingFunction {
+func NewManifestJSONProcessorFn(out io.Writer, opts NewManifestJSONProcessorFnOptions) ProcessingFunction {
 	return func(ctx context.Context, source <-chan *corev1.Pod, logger *slog.Logger) error {
 		m := discovery.Manifest{}
 
@@ -41,7 +45,14 @@ func NewManifestJSONProcessorFn(out io.Writer) ProcessingFunction {
 			return nil
 		}
 
-		manifestJSON, err := json.Marshal(m)
+		var manifestJSON []byte
+		var err error
+		if opts.CompactOutput {
+			manifestJSON, err = json.Marshal(m)
+		} else {
+			manifestJSON, err = json.MarshalIndent(m, "", "    ")
+		}
+
 		if err != nil {
 			logger.Error("unable to convert output manifest to JSON", "errMsg", err)
 			return err

internal/discover/processor_test.go

@@ -13,7 +13,7 @@ import (
 	"github.com/opdev/discover-workload/discovery"
 )
 
-func TestManifestInsert(t *testing.T) {
+func TestManifestAppend(t *testing.T) {
 	t.Parallel()
 	testcases := map[string]struct {
 		ctx      context.Context
@@ -391,6 +391,7 @@ func TestManifestJSONProcessor(t *testing.T) {
 	testcases := map[string]struct {
 		ctx      context.Context
 		input    []corev1.Pod
+		compact  bool
 		expected []byte
 	}{
 		"initContainer only": {
@@ -408,7 +409,26 @@ func TestManifestJSONProcessor(t *testing.T) {
 					},
 				},
 			},
-			expected: []byte("{\"DiscoveredImages\":[{\"Image\":\"example.com/namespace/image:0.0.1\",\"Containers\":[{\"Name\":\"init-cname\",\"Type\":\"InitContainer\",\"Pod\":{\"Name\":\"init-podname\",\"Namespace\":\"\"}}]}]}\n"),
+			compact:  false,
+			expected: []byte("{\n    \"DiscoveredImages\": [\n        {\n            \"Image\": \"example.com/namespace/image:0.0.1\",\n            \"Containers\": [\n                {\n                    \"Name\": \"init-cname\",\n                    \"Type\": \"InitContainer\",\n                    \"Pod\": {\n                        \"Name\": \"init-podname\",\n                        \"Namespace\": \"\"\n                    }\n                }\n            ]\n        }\n    ]\n}\n"),
+		},
+		"with raw printed JSON": {
+			ctx: context.TODO(),
+			input: []corev1.Pod{
+				{
+					ObjectMeta: metav1.ObjectMeta{Name: "podname"},
+					Spec: corev1.PodSpec{
+						Containers: []corev1.Container{
+							{
+								Name:  "cname",
+								Image: "example.com/namespace/image:0.0.1",
+							},
+						},
+					},
+				},
+			},
+			compact:  true,
+			expected: []byte("{\"DiscoveredImages\":[{\"Image\":\"example.com/namespace/image:0.0.1\",\"Containers\":[{\"Name\":\"cname\",\"Type\":\"Container\",\"Pod\":{\"Name\":\"podname\",\"Namespace\":\"\"}}]}]}\n"),
 		},
 	}
 
@@ -417,7 +437,10 @@ func TestManifestJSONProcessor(t *testing.T) {
 		t.Run(description, func(t *testing.T) {
 			t.Parallel()
 			buffer := bytes.NewBuffer([]byte{})
-			fn := NewManifestJSONProcessorFn(buffer)
+			opts := NewManifestJSONProcessorFnOptions{
+				CompactOutput: tc.compact,
+			}
+			fn := NewManifestJSONProcessorFn(buffer, opts)
 
 			ch := make(chan *corev1.Pod)