Add dry-run flag

cli/cmd/data/target.go

@@ -13,4 +13,5 @@ type TargetDetails struct {
 	Id            string
 	FileName      string
 	Alpine        bool
+	DryRun        bool
 }

cli/cmd/kubernetes/launch.go

@@ -5,12 +5,15 @@ package kubernetes
 import (
 	"context"
 	"fmt"
+	"k8s.io/apimachinery/pkg/runtime"
+	"os"
 
 	"github.com/VerizonMedia/kubectl-flame/cli/cmd/data"
 	batchv1 "k8s.io/api/batch/v1"
 	apiv1 "k8s.io/api/core/v1"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime/serializer/json"
 	"k8s.io/apimachinery/pkg/util/uuid"
 )
 
@@ -30,6 +33,10 @@ func LaunchFlameJob(targetPod *v1.Pod, targetDetails *data.TargetDetails, ctx co
 	}
 
 	job := &batchv1.Job{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "Job",
+			APIVersion: "batch/v1",
+		},
 		ObjectMeta: commonMeta,
 		Spec: batchv1.JobSpec{
 			Parallelism:             int32Ptr(1),
@@ -93,6 +100,11 @@ func LaunchFlameJob(targetPod *v1.Pod, targetDetails *data.TargetDetails, ctx co
 		},
 	}
 
+	if targetDetails.DryRun {
+		err := printJob(job)
+		return "", nil, err
+	}
+
 	createJob, err := clientSet.
 		BatchV1().
 		Jobs(targetDetails.Namespace).
@@ -105,6 +117,20 @@ func LaunchFlameJob(targetPod *v1.Pod, targetDetails *data.TargetDetails, ctx co
 	return id, createJob, nil
 }
 
+func printJob(job *batchv1.Job) error {
+	scheme := runtime.NewScheme()
+	err := metav1.AddMetaToScheme(scheme)
+	if err != nil {
+		return err
+	}
+
+	encoder := json.NewSerializerWithOptions(json.DefaultMetaFactory, scheme, scheme, json.SerializerOptions{
+		Yaml: true,
+	})
+
+	return encoder.Encode(job, os.Stdout)
+}
+
 func DeleteProfilingJob(job *batchv1.Job, targetDetails *data.TargetDetails, ctx context.Context) error {
 	deleteStrategy := metav1.DeletePropagationForeground
 	return clientSet.

cli/cmd/logic.go

@@ -17,62 +17,67 @@ import (
 
 func Flame(target *data.TargetDetails, configFlags *genericclioptions.ConfigFlags) {
 	ns, err := kubernetes.Connect(configFlags)
+	p := NewPrinter(target.DryRun)
 	if err != nil {
 		fmt.Printf("Failed connecting to kubernetes cluster: %v\n", err)
 		os.Exit(1)
 	}
 
 	target.Namespace = ns
 	ctx := context.Background()
-	fmt.Print("Verifying target pod ... ")
+	p.Print("Verifying target pod ... ")
 	pod, err := kubernetes.GetPodDetails(target.PodName, target.Namespace, ctx)
 	if err != nil {
-		PrintError()
+		p.PrintError()
 		fmt.Println(err.Error())
 		os.Exit(1)
 	}
 
 	containerName, err := validatePod(pod, target.ContainerName)
 	if err != nil {
-		PrintError()
+		p.PrintError()
 		fmt.Println(err.Error())
 		os.Exit(1)
 	}
 
 	containerId, err := kubernetes.GetContainerId(containerName, pod)
 	if err != nil {
-		PrintError()
+		p.PrintError()
 		fmt.Println(err.Error())
 		os.Exit(1)
 	}
 
-	PrintSuccess()
+	p.PrintSuccess()
 	target.ContainerName = containerName
 	target.ContainerId = containerId
-	fmt.Print("Launching profiler ... ")
+	p.Print("Launching profiler ... ")
 	profileId, job, err := kubernetes.LaunchFlameJob(pod, target, ctx)
 	if err != nil {
-		PrintError()
+		p.PrintError()
 		fmt.Print(err.Error())
 		os.Exit(1)
 	}
 
+	if target.DryRun {
+		return
+	}
+
 	target.Id = profileId
 	profilerPod, err := kubernetes.WaitForPodStart(target, ctx)
 	if err != nil {
-		PrintError()
+		p.PrintError()
 		fmt.Println(err.Error())
 		os.Exit(1)
 	}
 
-	PrintSuccess()
+	p.PrintSuccess()
 	apiHandler := &handler.ApiEventsHandler{
 		Job:    job,
 		Target: target,
 	}
 	done, err := kubernetes.GetLogsFromPod(profilerPod, apiHandler, ctx)
 	if err != nil {
-		PrintError()
+		p.PrintError()
 		fmt.Println(err.Error())
 	}
 

cli/cmd/root.go

@@ -71,6 +71,7 @@ func NewFlameCommand(streams genericclioptions.IOStreams) *cobra.Command {
 	cmd.Flags().DurationVarP(&targetDetails.Duration, "time", "t", defaultDuration, "Enter max scan Duration")
 	cmd.Flags().StringVarP(&targetDetails.FileName, "file", "f", "flamegraph.svg", "Optional file location")
 	cmd.Flags().BoolVar(&targetDetails.Alpine, "alpine", false, "Target image is based on Alpine")
+	cmd.Flags().BoolVar(&targetDetails.DryRun, "dry-run", false, "simulate profiling")
 	options.configFlags.AddFlags(cmd.Flags())
 
 	return cmd

cli/cmd/utils.go

@@ -4,10 +4,34 @@ package cmd
 
 import "fmt"
 
-func PrintSuccess() {
-	fmt.Printf("✔\n")
+type Printer interface {
+	Print(str string)
+	PrintSuccess()
+	PrintError()
 }
 
-func PrintError() {
+type dryRunPrinter struct {
+	dryRun bool
+}
+
+func (p *dryRunPrinter) Print(str string) {
+	if !p.dryRun {
+		fmt.Print(str)
+	}
+}
+
+func (p *dryRunPrinter) PrintSuccess() {
+	if !p.dryRun {
+		fmt.Printf("✔\n")
+	}
+}
+
+func (p *dryRunPrinter) PrintError() {
 	fmt.Printf("❌\n")
 }
+
+func NewPrinter(dryRun bool) Printer {
+	return &dryRunPrinter{
+		dryRun: dryRun,
+	}
+}