Address PR comments

pkg/activator/handler/handler.go

@@ -90,14 +90,12 @@ func New(l *zap.SugaredLogger, r activator.StatsReporter, t *activator.Throttler
 	}
 }
 
-func withOrigProto(or *http.Request) prober.Option {
-	return prober.Option{
-		Prepare: func(r *http.Request) *http.Request {
-			r.Proto = or.Proto
-			r.ProtoMajor = or.ProtoMajor
-			r.ProtoMinor = or.ProtoMinor
-			return r
-		},
+func withOrigProto(or *http.Request) prober.Preparer {
+	return func(r *http.Request) *http.Request {
+		r.Proto = or.Proto
+		r.ProtoMajor = or.ProtoMajor
+		r.ProtoMinor = or.ProtoMinor
+		return r
 	}
 }
 

pkg/network/prober/prober.go

@@ -31,42 +31,37 @@ import (
 // TransportFactory is a function which returns an HTTP transport.
 type TransportFactory func() http.RoundTripper
 
-// Option provides a way for the caller to mutate the HTTP request before it goes out,
-// and to validate the HTTP response after it comes back.
-type Option struct {
-	Prepare func(r *http.Request) *http.Request
-	Validate func(r *http.Response, b []byte) (bool, error)
-}
+// Preparer is a way for the caller to modify the HTTP request before it goes out.
+type Preparer func(r *http.Request) *http.Request
+
+// Verifier is a way for the caller to validate the HTTP response after it comes back.
+type Verifier func(r *http.Response, b []byte) (bool, error)
 
 // WithHeader sets a header in the probe request.
-func WithHeader(name, value string) Option {
-	return Option{
-		Prepare: func(r *http.Request) *http.Request {
-			r.Header.Set(name, value)
-			return r
-		},
+func WithHeader(name, value string) Preparer {
+	return func(r *http.Request) *http.Request {
+		r.Header.Set(name, value)
+		return r
 	}
 }
 
 // ExpectsBody validates that the body of the probe response matches the provided string.
-func ExpectsBody(body string) Option {
-	return Option{
-		Validate: func(r *http.Response, b []byte) (bool, error) {
-			return string(b) == body, nil
-		},
+func ExpectsBody(body string) Verifier {
+	return func(r *http.Response, b []byte) (bool, error) {
+		return string(b) == body, nil
 	}
 }
 
 // Do sends a single probe to given target, e.g. `http://revision.default.svc.cluster.local:81`.
 // Do returns whether the probe was successful or not, or there was an error probing.
-func Do(ctx context.Context, transport http.RoundTripper, target string, ops ...Option) (bool, error) {
+func Do(ctx context.Context, transport http.RoundTripper, target string, ops ...interface{}) (bool, error) {
 	req, err := http.NewRequest(http.MethodGet, target, nil)
 	if err != nil {
 		return false, errors.Wrapf(err, "%s is not a valid URL", target)
 	}
 	for _, op := range ops {
-		if op.Prepare != nil {
-			req = op.Prepare(req)
+		if po, ok := op.(Preparer); ok {
+			req = po(req)
 		}
 	}
 
@@ -82,8 +77,8 @@ func Do(ctx context.Context, transport http.RoundTripper, target string, ops ...
 	}
 
 	for _, op := range ops {
-		if op.Validate != nil {
-			ok, err := op.Validate(resp, body)
+		if vo, ok := op.(Verifier); ok {
+			ok, err := vo(resp, body)
 			if err != nil || !ok {
 				return false, err
 			}
@@ -131,7 +126,7 @@ func New(cb Done, transportFactory TransportFactory) *Manager {
 // Otherwise Offer starts a goroutine that periodically executes
 // `Do`, until timeout is reached, the probe succeeds, or fails with an error.
 // In the end the callback is invoked with the provided `arg` and probing results.
-func (m *Manager) Offer(ctx context.Context, target string, arg interface{}, period, timeout time.Duration, ops ...Option) bool {
+func (m *Manager) Offer(ctx context.Context, target string, arg interface{}, period, timeout time.Duration, ops ...interface{}) bool {
 	m.mu.Lock()
 	defer m.mu.Unlock()
 	if m.keys.Has(target) {
@@ -143,7 +138,7 @@ func (m *Manager) Offer(ctx context.Context, target string, arg interface{}, per
 }
 
 // doAsync starts a go routine that probes the target with given period.
-func (m *Manager) doAsync(ctx context.Context, transportFactory TransportFactory, target string, arg interface{}, period, timeout time.Duration, ops ...Option) {
+func (m *Manager) doAsync(ctx context.Context, transportFactory TransportFactory, target string, arg interface{}, period, timeout time.Duration, ops ...interface{}) {
 	go func() {
 		defer func() {
 			m.mu.Lock()

pkg/reconciler/autoscaling/kpa/scaler.go

@@ -49,14 +49,14 @@ const (
 	reenqeuePeriod = 1 * time.Second
 )
 
-var probeOptions = []prober.Option {
+var probeOptions = []interface{} {
 	prober.WithHeader(network.ProbeHeaderName, activator.Name),
 	prober.ExpectsBody(activator.Name),
 }
 
 // for mocking in tests
 type asyncProber interface {
-	Offer(context.Context, string, interface{}, time.Duration, time.Duration, ...prober.Option) bool
+	Offer(context.Context, string, interface{}, time.Duration, time.Duration, ...interface{}) bool
 }
 
 // scaler scales the target of a kpa-class PA up or down including scaling to zero.

pkg/reconciler/autoscaling/kpa/scaler_test.go

@@ -42,12 +42,11 @@ import (
 	"github.com/knative/serving/pkg/apis/serving/v1alpha1"
 	clientset "github.com/knative/serving/pkg/client/clientset/versioned"
 	"github.com/knative/serving/pkg/network"
-	"github.com/knative/serving/pkg/network/prober"
 	"github.com/knative/serving/pkg/reconciler/autoscaling/config"
 	revisionresources "github.com/knative/serving/pkg/reconciler/revision/resources"
 	"github.com/knative/serving/pkg/reconciler/revision/resources/names"
 	presources "github.com/knative/serving/pkg/resources"
-	v1 "k8s.io/api/apps/v1"
+	"k8s.io/api/apps/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -550,7 +549,7 @@ type countingProber struct {
 	count int
 }
 
-func (c *countingProber) Offer(ctx context.Context, target string, arg interface{}, period, timeout time.Duration, ops ...prober.Option) bool {
+func (c *countingProber) Offer(ctx context.Context, target string, arg interface{}, period, timeout time.Duration, ops ...interface{}) bool {
 	c.count++
 	return true
 }