Add unit tests for custom item rate limiter (knative#12733)

* Add unit tests for custom item rate limiter * Remove test for already covered scenarios
cpanato · Mar 18, 2022 · f1c08d8 · f1c08d8
1 parent ed92cdd
commit f1c08d8
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Showing 3 changed files with 105 additions and 40 deletions.
diff --git a/pkg/reconciler/revision/background_test.go b/pkg/reconciler/revision/background_test.go
@@ -25,7 +25,6 @@ import (
 	"testing"
 	"time"
 
-	"go.uber.org/atomic"
 	logtesting "knative.dev/pkg/logging/testing"
 	"knative.dev/pkg/ptr"
 
@@ -199,39 +198,6 @@ func TestResolveInBackground(t *testing.T) {
 	}
 }
 
-func TestRateLimitGlobal(t *testing.T) {
-	logger := logtesting.TestLogger(t)
-
-	var resolves atomic.Int32
-	var resolver resolveFunc = func(_ context.Context, _ string, _ k8schain.Options, _ sets.String) (string, error) {
-		resolves.Inc()
-		return "", errors.New("failed")
-	}
-
-	queue := workqueue.NewRateLimitingQueue(workqueue.NewItemExponentialFailureRateLimiter(1*time.Second, 5*time.Second))
-	subject := newBackgroundResolver(logger, resolver, queue, func(types.NamespacedName) {})
-
-	stop := make(chan struct{})
-	done := subject.Start(stop, 1)
-
-	defer func() {
-		close(stop)
-		<-done
-	}()
-
-	for i := 0; i < 5; i++ {
-		name := fmt.Sprint("rev", i)
-		subject.Resolve(logger, rev(name, name+"img1", name+"img2"), k8schain.Options{ServiceAccountName: "san"}, sets.NewString("skip"), 0)
-	}
-
-	// Rate limit base rate in this test is 1 second, so this should give time for at most 1 resolve.
-	time.Sleep(500 * time.Millisecond)
-
-	if r := resolves.Load(); r > 1 {
-		t.Fatalf("Expected resolves to be rate limited, but was called %d times", r)
-	}
-}
-
 func TestRateLimitPerItem(t *testing.T) {
 	logger := logtesting.TestLogger(t)
 
@@ -244,7 +210,7 @@ func TestRateLimitPerItem(t *testing.T) {
 	}
 
 	baseDelay := 50 * time.Millisecond
-	queue := workqueue.NewRateLimitingQueue(workqueue.NewItemExponentialFailureRateLimiter(baseDelay, 5*time.Second))
+	queue := workqueue.NewRateLimitingQueue(newItemExponentialFailureRateLimiter(baseDelay, 5*time.Second))
 
 	enqueue := make(chan struct{})
 	subject := newBackgroundResolver(logger, resolver, queue, func(types.NamespacedName) {
@@ -276,7 +242,8 @@ func TestRateLimitPerItem(t *testing.T) {
 		}
 
 		latency := time.Since(start)
-		expected := time.Duration(math.Pow(2, float64(i))) * baseDelay
+		// no delay on first resolve
+		expected := (time.Duration(math.Pow(2, float64(i-1))) * baseDelay)
 		if latency < expected {
 			t.Fatalf("latency = %s, want at least %s", latency, expected)
 		}
@@ -305,7 +272,8 @@ func TestRateLimitPerItem(t *testing.T) {
 		}
 
 		<-enqueue
-		if took := time.Since(start); took > baseDelay*2*2 {
+		// no delay on first resolve
+		if took := time.Since(start); took > (baseDelay * 2) {
 			t.Fatal("Expected Forget to remove revision from rate limiter, but took", took)
 		}
 	})

diff --git a/pkg/reconciler/revision/rate_limiter.go b/pkg/reconciler/revision/rate_limiter.go
@@ -31,9 +31,6 @@ import (
 //
 // Copyright 2016 The Kubernetes Authors.
 // From: https://github.com/kubernetes/client-go/blob/master/util/workqueue/default_rate_limiters.go
-//
-// TODO - drop this file when we pick up the following upstream change
-// https://github.com/kubernetes/kubernetes/pull/108343
 type itemExponentialFailureRateLimiter struct {
 	failuresLock sync.Mutex
 	failures     map[interface{}]int

diff --git a/pkg/reconciler/revision/rate_limiter_test.go b/pkg/reconciler/revision/rate_limiter_test.go
@@ -0,0 +1,100 @@
+/*
+Copyright 2022 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package revision
+
+import (
+	"testing"
+	"time"
+)
+
+// Copyright 2016 The Kubernetes Authors.
+// From: https://github.com/kubernetes/client-go/blob/master/util/workqueue/default_rate_limiters_test.go
+
+func TestItemExponentialFailureRateLimiter(t *testing.T) {
+	limiter := newItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Second)
+
+	if e, a := 0*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 1*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 4*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 8*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	if e, a := 0*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 1*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2, limiter.NumRequeues("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	limiter.Forget("one")
+	if e, a := 0, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 0*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}
+
+func TestItemExponentialFailureRateLimiterOverFlow(t *testing.T) {
+	limiter := newItemExponentialFailureRateLimiter(1*time.Millisecond, 1000*time.Second)
+	for i := 0; i < 5; i++ {
+		limiter.When("one")
+	}
+	if e, a := 16*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	for i := 0; i < 1000; i++ {
+		limiter.When("overflow1")
+	}
+	if e, a := 1000*time.Second, limiter.When("overflow1"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	limiter = newItemExponentialFailureRateLimiter(1*time.Minute, 1000*time.Hour)
+	for i := 0; i < 2; i++ {
+		limiter.When("two")
+	}
+	if e, a := 2*time.Minute, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	for i := 0; i < 1000; i++ {
+		limiter.When("overflow2")
+	}
+	if e, a := 1000*time.Hour, limiter.When("overflow2"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}