Merge pull request #126125 from mprahl/stop-idempotent

Allow calling Stop multiple times on RetryWatcher Kubernetes-commit: fc03f3e74c3d891e62b347c518b3197b62e9532c
kubernetes · Jul 23, 2024 · dcfcc90 · dcfcc90
2 parents bad8f77 + 001900e
commit dcfcc90
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Showing 4 changed files with 16 additions and 4 deletions.
diff --git a/go.mod b/go.mod
@@ -25,7 +25,7 @@ require (
 	golang.org/x/time v0.3.0
 	google.golang.org/protobuf v1.34.2
 	gopkg.in/evanphx/json-patch.v4 v4.12.0
-	k8s.io/api v0.0.0-20240722223049-b689d905290f
+	k8s.io/api v0.0.0-20240723194852-3421a80713ae
 	k8s.io/apimachinery v0.0.0-20240720202316-95b78024e3fe
 	k8s.io/klog/v2 v2.130.1
 	k8s.io/kube-openapi v0.0.0-20240228011516-70dd3763d340

diff --git a/go.sum b/go.sum
@@ -156,8 +156,8 @@ gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-k8s.io/api v0.0.0-20240722223049-b689d905290f h1:wtqzslJEcheiQ7hXjw1yGfqUyMCb7G4j72aL64Bzpbo=
-k8s.io/api v0.0.0-20240722223049-b689d905290f/go.mod h1:ytlEzqC2wOTwYET71W7+J+k7O2V7vrDuzmNLBSpgT+k=
+k8s.io/api v0.0.0-20240723194852-3421a80713ae h1:mV43yijQh5/Wf7fwSuyATasDFY+YJxjuXs1ecY5M1Bc=
+k8s.io/api v0.0.0-20240723194852-3421a80713ae/go.mod h1:ytlEzqC2wOTwYET71W7+J+k7O2V7vrDuzmNLBSpgT+k=
 k8s.io/apimachinery v0.0.0-20240720202316-95b78024e3fe h1:V9MwpYUwbKlfLKVrhpVuKWiat/LBIhm1pGB9/xdHm5Q=
 k8s.io/apimachinery v0.0.0-20240720202316-95b78024e3fe/go.mod h1:rsPdaZJfTfLsNJSQzNHQvYoTmxhoOEofxtOsF3rtsMo=
 k8s.io/klog/v2 v2.130.1 h1:n9Xl7H1Xvksem4KFG4PYbdQCQxqc/tTUyrgXaOhHSzk=

diff --git a/tools/watch/retrywatcher.go b/tools/watch/retrywatcher.go
@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"sync"
 	"time"
 
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -53,6 +54,7 @@ type RetryWatcher struct {
 	stopChan            chan struct{}
 	doneChan            chan struct{}
 	minRestartDelay     time.Duration
+	stopChanLock        sync.Mutex
 }
 
 // NewRetryWatcher creates a new RetryWatcher.
@@ -286,7 +288,15 @@ func (rw *RetryWatcher) ResultChan() <-chan watch.Event {
 
 // Stop implements Interface.
 func (rw *RetryWatcher) Stop() {
-	close(rw.stopChan)
+	rw.stopChanLock.Lock()
+	defer rw.stopChanLock.Unlock()
+
+	// Prevent closing an already closed channel to prevent a panic
+	select {
+	case <-rw.stopChan:
+	default:
+		close(rw.stopChan)
+	}
 }
 
 // Done allows the caller to be notified when Retry watcher stops.

diff --git a/tools/watch/retrywatcher_test.go b/tools/watch/retrywatcher_test.go
@@ -585,6 +585,8 @@ func TestRetryWatcherToFinishWithUnreadEvents(t *testing.T) {
 	// Give the watcher a chance to get to sending events (blocking)
 	time.Sleep(10 * time.Millisecond)
 
+	watcher.Stop()
+	// Verify a second stop does not cause a panic
 	watcher.Stop()
 
 	maxTime := time.Second