Repository: knative/client (go)

Issue:
Add `--scale-activation` flag to match new Serving option
<!-- If you need to report a security issue with Knative, send an email to knative-security@googlegroups.com. -->

### Feature request

Consider adding a new Ksvc flag to specify activation scale value. That represents number of replicas to be scaled from zero when service is activated.

Ref: https://github.com/knative/serving/pull/13161 (note it's an update PR to introduce new & current name of option)
https://github.com/knative/serving/pull/13136 (first PR with former name)

### UI Example



```
kn service create hello --image .../myapp --scale-activation 2
```

/kind good-first-issue

/cc @dprotaso @psschwei 
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Pull request:
Add --scale-activation flag to match new Serving option
## Description
Add --scale-activation flag to match new Serving option
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## Changes

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* Added the flag
* Added unit and e2e tests

## Reference

<!-- Please add the corresponding issue number which this pull request is about to fix -->
Fixes #1713 

**Release Note**

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additional action from users switching to the new release, include the string
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```release-note
Add `--scale-activation` flag to `service create` command options
```

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Patch:
diff --git a/docs/cmd/kn_service_apply.md b/docs/cmd/kn_service_apply.md
index 04448c46..fa816735 100644
--- a/docs/cmd/kn_service_apply.md
+++ b/docs/cmd/kn_service_apply.md
@@ -65,6 +65,7 @@ kn service apply s0 --filename my-svc.yml
       --request strings                   The resource requirement requests for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource request, append "-" to the resource name, e.g. '--request cpu-'.
       --revision-name string              The revision name to set. Must start with the service name and a dash as a prefix. Empty revision name will result in the server generating a name for the revision. Accepts golang templates, allowing {{.Service}} for the service name, {{.Generation}} for the generation, and {{.Random [n]}} for n random consonants (e.g. {{.Service}}-{{.Random 5}}-{{.Generation}})
       --scale string                      Set the Minimum and Maximum number of replicas. You can use this flag to set both to a single value, or set a range with min/max values, or set either min or max values without specifying the other. Example: --scale 5 (scale-min = 5, scale-max = 5) or --scale 1..5 (scale-min = 1, scale-max = 5) or --scale 1.. (scale-min = 1, scale-max = unchanged) or --scale ..5 (scale-min = unchanged, scale-max = 5)
+      --scale-activation int              Minimum non-zero value that a service should scale to.
       --scale-init int                    Initial number of replicas with which a service starts. Can be 0 or a positive integer.
       --scale-max int                     Maximum number of replicas.
       --scale-metric string               Set the name of the metric the PodAutoscaler should scale on. Example: --scale-metric rps (to scale on rps) or --scale-metric concurrency (to scale on concurrency). The default metric is concurrency.
diff --git a/docs/cmd/kn_service_create.md b/docs/cmd/kn_service_create.md
index 3133ec40..0221644d 100644
--- a/docs/cmd/kn_service_create.md
+++ b/docs/cmd/kn_service_create.md
@@ -90,6 +90,7 @@ kn service create NAME --image IMAGE
       --request strings                   The resource requirement requests for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource request, append "-" to the resource name, e.g. '--request cpu-'.
       --revision-name string              The revision name to set. Must start with the service name and a dash as a prefix. Empty revision name will result in the server generating a name for the revision. Accepts golang templates, allowing {{.Service}} for the service name, {{.Generation}} for the generation, and {{.Random [n]}} for n random consonants (e.g. {{.Service}}-{{.Random 5}}-{{.Generation}})
       --scale string                      Set the Minimum and Maximum number of replicas. You can use this flag to set both to a single value, or set a range with min/max values, or set either min or max values without specifying the other. Example: --scale 5 (scale-min = 5, scale-max = 5) or --scale 1..5 (scale-min = 1, scale-max = 5) or --scale 1.. (scale-min = 1, scale-max = unchanged) or --scale ..5 (scale-min = unchanged, scale-max = 5)
+      --scale-activation int              Minimum non-zero value that a service should scale to.
       --scale-init int                    Initial number of replicas with which a service starts. Can be 0 or a positive integer.
       --scale-max int                     Maximum number of replicas.
       --scale-metric string               Set the name of the metric the PodAutoscaler should scale on. Example: --scale-metric rps (to scale on rps) or --scale-metric concurrency (to scale on concurrency). The default metric is concurrency.
diff --git a/docs/cmd/kn_service_update.md b/docs/cmd/kn_service_update.md
index 42295def..89280731 100644
--- a/docs/cmd/kn_service_update.md
+++ b/docs/cmd/kn_service_update.md
@@ -77,6 +77,7 @@ kn service update NAME
       --request strings                   The resource requirement requests for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource request, append "-" to the resource name, e.g. '--request cpu-'.
       --revision-name string              The revision name to set. Must start with the service name and a dash as a prefix. Empty revision name will result in the server generating a name for the revision. Accepts golang templates, allowing {{.Service}} for the service name, {{.Generation}} for the generation, and {{.Random [n]}} for n random consonants (e.g. {{.Service}}-{{.Random 5}}-{{.Generation}})
       --scale string                      Set the Minimum and Maximum number of replicas. You can use this flag to set both to a single value, or set a range with min/max values, or set either min or max values without specifying the other. Example: --scale 5 (scale-min = 5, scale-max = 5) or --scale 1..5 (scale-min = 1, scale-max = 5) or --scale 1.. (scale-min = 1, scale-max = unchanged) or --scale ..5 (scale-min = unchanged, scale-max = 5)
+      --scale-activation int              Minimum non-zero value that a service should scale to.
       --scale-init int                    Initial number of replicas with which a service starts. Can be 0 or a positive integer.
       --scale-max int                     Maximum number of replicas.
       --scale-metric string               Set the name of the metric the PodAutoscaler should scale on. Example: --scale-metric rps (to scale on rps) or --scale-metric concurrency (to scale on concurrency). The default metric is concurrency.
diff --git a/pkg/kn/commands/service/configuration_edit_flags.go b/pkg/kn/commands/service/configuration_edit_flags.go
index b2dcbcba..17c9798a 100644
--- a/pkg/kn/commands/service/configuration_edit_flags.go
+++ b/pkg/kn/commands/service/configuration_edit_flags.go
@@ -41,6 +41,7 @@ type ConfigurationEditFlags struct {
 	Scale               string
 	MinScale            int
 	MaxScale            int
+	ScaleActivation     int
 	ScaleTarget         int
 	ScaleMetric         string
 	ConcurrencyLimit    int
@@ -94,6 +95,9 @@ func (p *ConfigurationEditFlags) addSharedFlags(command *cobra.Command) {
 	command.Flags().IntVar(&p.MaxScale, "scale-max", 0, "Maximum number of replicas.")
 	p.markFlagMakesRevision("scale-max")
 
+	command.Flags().IntVar(&p.ScaleActivation, "scale-activation", 0, "Minimum non-zero value that a service should scale to.")
+	p.markFlagMakesRevision("scale-activation")
+
 	command.Flags().StringVar(&p.ScaleMetric, "scale-metric", "", "Set the name of the metric the PodAutoscaler should scale on. "+
 		"Example: --scale-metric rps (to scale on rps) or --scale-metric concurrency (to scale on concurrency). The default metric is concurrency.")
 	p.markFlagMakesRevision("scale-metric")
@@ -358,6 +362,10 @@ func (p *ConfigurationEditFlags) Apply(
 		servinglib.UpdateScaleMetric(template, p.ScaleMetric)
 	}
 
+	if cmd.Flags().Changed("scale-activation") {
+		servinglib.UpdateScaleActivation(template, p.ScaleActivation)
+	}
+
 	if cmd.Flags().Changed("concurrency-limit") {
 		err = servinglib.UpdateConcurrencyLimit(template, int64(p.ConcurrencyLimit))
 		if err != nil {
diff --git a/pkg/serving/config_changes.go b/pkg/serving/config_changes.go
index 56847797..6e7b9a7b 100644
--- a/pkg/serving/config_changes.go
+++ b/pkg/serving/config_changes.go
@@ -77,6 +77,11 @@ func UpdateScaleTarget(template *servingv1.RevisionTemplateSpec, target int) err
 	return UpdateRevisionTemplateAnnotation(template, autoscaling.TargetAnnotationKey, strconv.Itoa(target))
 }
 
+//UpdateScaleActivation updates the scale activation annotation
+func UpdateScaleActivation(template *servingv1.RevisionTemplateSpec, activation int) error {
+	return UpdateRevisionTemplateAnnotation(template, autoscaling.ActivationScaleKey, strconv.Itoa(activation))
+}
+
 // UpdateScaleUtilization updates container target utilization percentage annotation
 func UpdateScaleUtilization(template *servingv1.RevisionTemplateSpec, target int) error {
 	return UpdateRevisionTemplateAnnotation(template, autoscaling.TargetUtilizationPercentageKey, strconv.Itoa(target))


Test patch:
diff --git a/pkg/kn/commands/service/configuration_edit_flags_test.go b/pkg/kn/commands/service/configuration_edit_flags_test.go
index e5596656..853407e8 100644
--- a/pkg/kn/commands/service/configuration_edit_flags_test.go
+++ b/pkg/kn/commands/service/configuration_edit_flags_test.go
@@ -20,6 +20,7 @@ import (
 	"gotest.tools/v3/assert"
 	"knative.dev/client/pkg/kn/commands"
 	"knative.dev/client/pkg/util"
+	"knative.dev/serving/pkg/apis/autoscaling"
 )
 
 func TestApplyPullPolicyFlag(t *testing.T) {
@@ -60,3 +61,17 @@ func TestScaleMetric(t *testing.T) {
 	err := editFlags.Apply(&svc, nil, cmd)
 	assert.NilError(t, err)
 }
+
+func TestScaleActivation(t *testing.T) {
+	var editFlags ConfigurationEditFlags
+	knParams := &commands.KnParams{}
+	cmd, _, _ := commands.CreateTestKnCommand(NewServiceCreateCommand(knParams), knParams)
+
+	editFlags.AddCreateFlags(cmd)
+	svc := createTestService("test-svc", []string{"test-svc-00001"}, goodConditions())
+	cmd.SetArgs([]string{"--scale-activation", "2"})
+	cmd.Execute()
+	err := editFlags.Apply(&svc, nil, cmd)
+	assert.NilError(t, err)
+	assert.Equal(t, svc.Spec.Template.Annotations[autoscaling.ActivationScaleKey], "2")
+}
diff --git a/test/e2e/service_options_test.go b/test/e2e/service_options_test.go
index ab11b01c..ce1962c4 100644
--- a/test/e2e/service_options_test.go
+++ b/test/e2e/service_options_test.go
@@ -231,6 +231,10 @@ func TestServiceOptions(t *testing.T) {
 	test.ServiceDelete(r, "svc17")
 	_, err = kubectl.Run("delete", "-n", it.Namespace(), "configmap", "test-cm2")
 	assert.NilError(t, err)
+
+	t.Log("create and validate a service with scale activation")
+	serviceCreateWithOptions(r, "svc18", "--scale-activation", "2")
+	validateServiceActivation(r, "svc18", 2)
 }
 
 func serviceCreateWithOptions(r *test.KnRunResultCollector, serviceName string, options ...string) {
@@ -384,3 +388,12 @@ func validateServiceEnvVariables(r *test.KnRunResultCollector, serviceName strin
 		}
 	}
 }
+
+func validateServiceActivation(r *test.KnRunResultCollector, serviceName string, activation int) {
+	out := r.KnTest().Kn().Run("service", "describe", serviceName, "-o", "json")
+	r.AssertNoError(out)
+	var svc servingv1.Service
+	json.Unmarshal([]byte(out.Stdout), &svc)
+	activationStr := strconv.Itoa(activation)
+	assert.Check(r.T(), svc.Spec.Template.Annotations[autoscaling.ActivationScaleKey] == activationStr)
+}