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client-go/cache/testing: add ability to simulate watch disruption

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This adds ResetWatch() to the FakeControllerSource, which lets the
controller simulate a re-list-and-watch.
This commit is contained in:
Casey Callendrello 2019-12-06 22:19:42 +01:00
parent 33aa665c34
commit 5aacacbdf0
3 changed files with 83 additions and 13 deletions
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1
staging/src/k8s.io/client-go/tools/cache/testing/BUILD vendored
View File

@ -24,6 +24,7 @@ go_library(
importpath = "k8s.io/client-go/tools/cache/testing",
deps = [
"//staging/src/k8s.io/api/core/v1:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/api/meta:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",

52
staging/src/k8s.io/client-go/tools/cache/testing/fake_controller_source.go vendored
View File

@ -18,11 +18,13 @@ package framework
import (
"errors"
"fmt"
"math/rand"
"strconv"
"sync"
"k8s.io/api/core/v1"
v1 "k8s.io/api/core/v1"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/api/meta"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
@ -59,6 +61,7 @@ type FakeControllerSource struct {
Items map[nnu]runtime.Object
changes []watch.Event // one change per resourceVersion
Broadcaster *watch.Broadcaster
lastRV int
}
type FakePVControllerSource struct {
@ -75,6 +78,16 @@ type nnu struct {
uid types.UID
}
// ResetWatch simulates connection problems; creates a new Broadcaster and flushes
// the change queue so that clients have to re-list and watch.
func (f *FakeControllerSource) ResetWatch() {
f.lock.Lock()
defer f.lock.Unlock()
f.Broadcaster.Shutdown()
f.Broadcaster = watch.NewBroadcaster(100, watch.WaitIfChannelFull)
f.changes = []watch.Event{}
}
// Add adds an object to the set and sends an add event to watchers.
// obj's ResourceVersion is set.
func (f *FakeControllerSource) Add(obj runtime.Object) {
@ -129,8 +142,8 @@ func (f *FakeControllerSource) Change(e watch.Event, watchProbability float64) {
panic(err) // this is test code only
}
resourceVersion := len(f.changes) + 1
accessor.SetResourceVersion(strconv.Itoa(resourceVersion))
f.lastRV += 1
accessor.SetResourceVersion(strconv.Itoa(f.lastRV))
f.changes = append(f.changes, e)
key := f.key(accessor)
switch e.Type {
@ -173,8 +186,7 @@ func (f *FakeControllerSource) List(options metav1.ListOptions) (runtime.Object,
if err != nil {
return nil, err
}
resourceVersion := len(f.changes)
listAccessor.SetResourceVersion(strconv.Itoa(resourceVersion))
listAccessor.SetResourceVersion(strconv.Itoa(f.lastRV))
return listObj, nil
}
@ -194,8 +206,7 @@ func (f *FakePVControllerSource) List(options metav1.ListOptions) (runtime.Objec
if err != nil {
return nil, err
}
resourceVersion := len(f.changes)
listAccessor.SetResourceVersion(strconv.Itoa(resourceVersion))
listAccessor.SetResourceVersion(strconv.Itoa(f.lastRV))
return listObj, nil
}
@ -215,8 +226,7 @@ func (f *FakePVCControllerSource) List(options metav1.ListOptions) (runtime.Obje
if err != nil {
return nil, err
}
resourceVersion := len(f.changes)
listAccessor.SetResourceVersion(strconv.Itoa(resourceVersion))
listAccessor.SetResourceVersion(strconv.Itoa(f.lastRV))
return listObj, nil
}
@ -229,9 +239,27 @@ func (f *FakeControllerSource) Watch(options metav1.ListOptions) (watch.Interfac
if err != nil {
return nil, err
}
if rc < len(f.changes) {
if rc < f.lastRV {
// if the change queue was flushed...
if len(f.changes) == 0 {
return nil, apierrors.NewResourceExpired(fmt.Sprintf("too old resource version: %d (%d)", rc, f.lastRV))
}
// get the RV of the oldest object in the change queue
oldestRV, err := meta.NewAccessor().ResourceVersion(f.changes[0].Object)
if err != nil {
panic(err)
}
oldestRC, err := strconv.Atoi(oldestRV)
if err != nil {
panic(err)
}
if rc < oldestRC {
return nil, apierrors.NewResourceExpired(fmt.Sprintf("too old resource version: %d (%d)", rc, oldestRC))
}
changes := []watch.Event{}
for _, c := range f.changes[rc:] {
for _, c := range f.changes[rc-oldestRC+1:] {
// Must make a copy to allow clients to modify the
// object. Otherwise, if they make a change and write
// it back, they will inadvertently change the our
@ -240,7 +268,7 @@ func (f *FakeControllerSource) Watch(options metav1.ListOptions) (watch.Interfac
changes = append(changes, watch.Event{Type: c.Type, Object: c.Object.DeepCopyObject()})
}
return f.Broadcaster.WatchWithPrefix(changes), nil
} else if rc > len(f.changes) {
} else if rc > f.lastRV {
return nil, errors.New("resource version in the future not supported by this fake")
}
return f.Broadcaster.Watch(), nil

43
staging/src/k8s.io/client-go/tools/cache/testing/fake_controller_source_test.go vendored
View File

@ -20,7 +20,7 @@ import (
"sync"
"testing"
"k8s.io/api/core/v1"
v1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/watch"
)
@ -93,3 +93,44 @@ func TestRCNumber(t *testing.T) {
source.Shutdown()
wg.Wait()
}
// TestResetWatch validates that the FakeController correctly mocks a watch
// falling behind and ResourceVersions aging out.
func TestResetWatch(t *testing.T) {
pod := func(name string) *v1.Pod {
return &v1.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: name,
},
}
}
wg := &sync.WaitGroup{}
wg.Add(1)
source := NewFakeControllerSource()
source.Add(pod("foo")) // RV = 1
source.Modify(pod("foo")) // RV = 2
source.Modify(pod("foo")) // RV = 3
// Kill watch, delete change history
source.ResetWatch()
// This should fail, RV=1 was lost with ResetWatch
_, err := source.Watch(metav1.ListOptions{ResourceVersion: "1"})
if err == nil {
t.Fatalf("Unexpected non-error")
}
// This should succeed, RV=3 is current
w, err := source.Watch(metav1.ListOptions{ResourceVersion: "3"})
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
// Modify again, ensure the watch is still working
source.Modify(pod("foo"))
go consume(t, w, []string{"4"}, wg)
source.Shutdown()
wg.Wait()
}