From 2da3ffefc0780a80289f7aa944840a7b14e54070 Mon Sep 17 00:00:00 2001
From: Paschalis Tsilias <tpaschalis@users.noreply.github.com>
Date: Tue, 10 Oct 2023 17:33:05 +0300
Subject: [PATCH] operator: initialise default namespaces map config (#5424)
 (#5426)

(cherry picked from commit 37c40cc530c101d993f063d1825f384738531bcd)

Co-authored-by: William Dumont <william.dumont@grafana.com>
---
 component/loki/source/kubernetes_events/event_controller.go | 4 +++-
 component/prometheus/operator/common/crdmanager.go          | 2 ++
 pkg/operator/operator.go                                    | 5 ++++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/component/loki/source/kubernetes_events/event_controller.go b/component/loki/source/kubernetes_events/event_controller.go
index d6ddd8d41833..c161f01a288f 100644
--- a/component/loki/source/kubernetes_events/event_controller.go
+++ b/component/loki/source/kubernetes_events/event_controller.go
@@ -97,7 +97,9 @@ func (ctrl *eventController) runError(ctx context.Context) error {
 	}
 
 	defaultNamespaces := map[string]cache.Config{}
-	defaultNamespaces[ctrl.task.Namespace] = cache.Config{}
+	if ctrl.task.Namespace != "" {
+		defaultNamespaces[ctrl.task.Namespace] = cache.Config{}
+	}
 	opts := cache.Options{
 		Scheme:            scheme,
 		DefaultNamespaces: defaultNamespaces,
diff --git a/component/prometheus/operator/common/crdmanager.go b/component/prometheus/operator/common/crdmanager.go
index 7ce1aa368827..fe75e5714b47 100644
--- a/component/prometheus/operator/common/crdmanager.go
+++ b/component/prometheus/operator/common/crdmanager.go
@@ -243,6 +243,8 @@ func (c *crdManager) runInformers(restConfig *rest.Config, ctx context.Context)
 		return fmt.Errorf("building label selector: %w", err)
 	}
 	for _, ns := range c.args.Namespaces {
+		// TODO: This is going down an unnecessary extra step in the cache when `c.args.Namespaces` defaults to NamespaceAll.
+		// This code path should be simplified and support a scenario when len(c.args.Namespace) == 0.
 		defaultNamespaces := map[string]cache.Config{}
 		defaultNamespaces[ns] = cache.Config{}
 		opts := cache.Options{
diff --git a/pkg/operator/operator.go b/pkg/operator/operator.go
index c1c08862473d..adad79288ec7 100644
--- a/pkg/operator/operator.go
+++ b/pkg/operator/operator.go
@@ -87,7 +87,10 @@ func (c *Config) registerFlags(f *flag.FlagSet) error {
 
 	c.Controller.WebhookServer = webhook.NewServer(webhookServerOptions)
 
-	c.Controller.Cache.DefaultNamespaces[namespace] = cache.Config{}
+	if namespace != "" {
+		c.Controller.Cache.DefaultNamespaces = map[string]cache.Config{}
+		c.Controller.Cache.DefaultNamespaces[namespace] = cache.Config{}
+	}
 
 	// Custom initial values for the endpoint names.
 	c.Controller.ReadinessEndpointName = "/-/ready"