Adds --force flag to service create command (service replace) (#79)

* Adds --force flag to service create command / service replace

 Fixes #13

* Keeps the resourceVersion of service with --force flag

* Updates the tests

* Removes unnecessary comments

pkg/kn/commands/configuration_edit_flags.go

@@ -29,6 +29,7 @@ type ConfigurationEditFlags struct {
 	Image                      string
 	Env                        []string
 	RequestsFlags, LimitsFlags ResourceFlags
+	ForceCreate                bool
 }
 
 type ResourceFlags struct {
@@ -49,6 +50,7 @@ func (p *ConfigurationEditFlags) AddUpdateFlags(command *cobra.Command) {
 
 func (p *ConfigurationEditFlags) AddCreateFlags(command *cobra.Command) {
 	p.AddUpdateFlags(command)
+	command.Flags().BoolVar(&p.ForceCreate, "force", false, "Create service forcefully, replaces existing service if any.")
 	command.MarkFlagRequired("image")
 }
 

pkg/kn/commands/service_create.go

@@ -22,6 +22,7 @@ import (
 	servingv1alpha1 "github.com/knative/serving/pkg/apis/serving/v1alpha1"
 	"github.com/spf13/cobra"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
 func NewServiceCreateCommand(p *KnParams) *cobra.Command {
@@ -35,7 +36,19 @@ func NewServiceCreateCommand(p *KnParams) *cobra.Command {
   kn service create mysvc --image dev.local/ns/image:latest
 
   # Create a service with multiple environment variables
-  kn service create mysvc --env KEY1=VALUE1 --env KEY2=VALUE2 --image dev.local/ns/image:latest`,
+  kn service create mysvc --env KEY1=VALUE1 --env KEY2=VALUE2 --image dev.local/ns/image:latest
+
+  # Create or replace a service 's1' with image dev.local/ns/image:v2 using --force flag
+  # if service 's1' doesn't exist, it's just a normal create operation
+  kn service create --force s1 --image dev.local/ns/image:v2
+
+  # Create or replace environment variables of service 's1' using --force flag
+  kn service create --force s1 --env KEY1=NEW_VALUE1 --env NEW_KEY2=NEW_VALUE2 --image dev.local/ns/image:v1
+
+  # Create or replace default resources of a service 's1' using --force flag
+  # (earlier configured resource requests and limits will be replaced with default)
+  # (earlier configured environment variables will be cleared too if any)
+  kn service create --force s1 --image dev.local/ns/image:v1`,
 
 		RunE: func(cmd *cobra.Command, args []string) (err error) {
 			if len(args) != 1 {
@@ -70,11 +83,26 @@ func NewServiceCreateCommand(p *KnParams) *cobra.Command {
 			if err != nil {
 				return err
 			}
-			_, err = client.Services(namespace).Create(&service)
-			if err != nil {
-				return err
+			var serviceExists bool = false
+			if editFlags.ForceCreate {
+				existingService, err := client.Services(namespace).Get(args[0], v1.GetOptions{})
+				if err == nil {
+					serviceExists = true
+					service.ResourceVersion = existingService.ResourceVersion
+					_, err = client.Services(namespace).Update(&service)
+					if err != nil {
+						return err
+					}
+					fmt.Fprintf(cmd.OutOrStdout(), "Service '%s' successfully replaced in namespace '%s'.\n", args[0], namespace)
+				}
+			}
+			if !serviceExists {
+				_, err = client.Services(namespace).Create(&service)
+				if err != nil {
+					return err
+				}
+				fmt.Fprintf(cmd.OutOrStdout(), "Service '%s' successfully created in namespace '%s'.\n", args[0], namespace)
 			}
-			fmt.Fprintf(cmd.OutOrStdout(), "Service '%s' successfully created in namespace '%s'.\n", args[0], namespace)
 			return nil
 		},
 	}

pkg/kn/commands/service_create_test.go

@@ -290,3 +290,63 @@ func parseQuantity(t *testing.T, quantityString string) resource.Quantity {
 	}
 	return quantity
 }
+
+func TestServiceCreateImageForce(t *testing.T) {
+	_, _, _, err := fakeServiceCreate([]string{
+		"service", "create", "foo", "--image", "gcr.io/foo/bar:v1"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	action, created, output, err := fakeServiceCreate([]string{
+		"service", "create", "foo", "--force", "--image", "gcr.io/foo/bar:v2"})
+	if err != nil {
+		t.Fatal(err)
+	} else if !action.Matches("create", "services") {
+		t.Fatalf("Bad action %v", action)
+	}
+	conf, err := servinglib.GetConfiguration(created)
+	if err != nil {
+		t.Fatal(err)
+	} else if conf.RevisionTemplate.Spec.Container.Image != "gcr.io/foo/bar:v2" {
+		t.Fatalf("wrong image set: %v", conf.RevisionTemplate.Spec.Container.Image)
+	} else if !strings.Contains(output, "foo") || !strings.Contains(output, "default") {
+		t.Fatalf("wrong output: %s", output)
+	}
+}
+
+func TestServiceCreateEnvForce(t *testing.T) {
+	_, _, _, err := fakeServiceCreate([]string{
+		"service", "create", "foo", "--image", "gcr.io/foo/bar:v1", "-e", "A=DOGS", "--env", "B=WOLVES"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	action, created, output, err := fakeServiceCreate([]string{
+		"service", "create", "foo", "--force", "--image", "gcr.io/foo/bar:v2", "-e", "A=CATS", "--env", "B=LIONS"})
+
+	if err != nil {
+		t.Fatal(err)
+	} else if !action.Matches("create", "services") {
+		t.Fatalf("Bad action %v", action)
+	}
+
+	expectedEnvVars := map[string]string{
+		"A": "CATS",
+		"B": "LIONS"}
+
+	conf, err := servinglib.GetConfiguration(created)
+	actualEnvVars, err := servinglib.EnvToMap(conf.RevisionTemplate.Spec.Container.Env)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err != nil {
+		t.Fatal(err)
+	} else if conf.RevisionTemplate.Spec.Container.Image != "gcr.io/foo/bar:v2" {
+		t.Fatalf("wrong image set: %v", conf.RevisionTemplate.Spec.Container.Image)
+	} else if !reflect.DeepEqual(
+		actualEnvVars,
+		expectedEnvVars) {
+		t.Fatalf("wrong env vars:%v", conf.RevisionTemplate.Spec.Container.Env)
+	} else if !strings.Contains(output, "foo") || !strings.Contains(output, "default") {
+		t.Fatalf("wrong output: %s", output)
+	}
+}