From 6e9609409b38453b3a1198e849a3973d4585b17e Mon Sep 17 00:00:00 2001 From: Thomas Hartland <11710676+tghartland@users.noreply.github.com> Date: Mon, 11 Jul 2022 17:21:20 +0100 Subject: [PATCH] Use non-blocking channel send for UpdateWebhookChan (#4204) If the channel send is blocked then there is already an update queued, and there is no point waiting to queue another one. In profiling, the channel send in monitor.go has been seen to "leak" goroutines as the channel is not being read from fast enough, but the root cause is not known. Signed-off-by: Thomas Hartland --- pkg/webhookconfig/monitor.go | 8 ++++++-- pkg/webhookconfig/registration.go | 7 ++++++- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/pkg/webhookconfig/monitor.go b/pkg/webhookconfig/monitor.go index fa058eccad..e6e56ad58d 100644 --- a/pkg/webhookconfig/monitor.go +++ b/pkg/webhookconfig/monitor.go @@ -116,8 +116,12 @@ func (t *Monitor) Run(register *Register, certRenewer *tls.CertRenewer, eventGen // update namespaceSelector every 30 seconds go func() { if register.autoUpdateWebhooks { - logger.V(4).Info("updating webhook configurations for namespaceSelector with latest kyverno ConfigMap") - register.UpdateWebhookChan <- true + select { + case register.UpdateWebhookChan <- true: + logger.V(4).Info("updating webhook configurations for namespaceSelector with latest kyverno ConfigMap") + default: + logger.V(4).Info("skipped sending update webhook signal as the channel was blocking") + } } }() diff --git a/pkg/webhookconfig/registration.go b/pkg/webhookconfig/registration.go index 31f2276584..0196137e97 100644 --- a/pkg/webhookconfig/registration.go +++ b/pkg/webhookconfig/registration.go @@ -246,7 +246,12 @@ func (wrc *Register) UpdateWebhookConfigurations(configHandler config.Configurat if retry { go func() { time.Sleep(1 * time.Second) - wrc.UpdateWebhookChan <- true + select { + case wrc.UpdateWebhookChan <- true: + return + default: + return + } }() } }