Fixing WATCH_NAMESPACE env variable handling for single namespace value (#2606)

Author: davidhaja

.chloggen/fix_2589-watch-single-namespace.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. operator, target allocator, github action)
+component: operator
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Fixing WATCH_NAMESPACE for a single namespace value"
+
+# One or more tracking issues related to the change
+issues: [2589]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

main.go

@@ -196,9 +196,14 @@ func main() {
 		setupLog.Error(err, "failed to autodetect config variables")
 	}
 
+	var namespaces map[string]cache.Config
 	watchNamespace, found := os.LookupEnv("WATCH_NAMESPACE")
 	if found {
 		setupLog.Info("watching namespace(s)", "namespaces", watchNamespace)
+		namespaces = map[string]cache.Config{}
+		for _, ns := range strings.Split(watchNamespace, ",") {
+			namespaces[ns] = cache.Config{}
+		}
 	} else {
 		setupLog.Info("the env var WATCH_NAMESPACE isn't set, watching all namespaces")
 	}
@@ -211,13 +216,6 @@ func main() {
 	optionsTlSOptsFuncs := []func(*tls.Config){
 		func(config *tls.Config) { tlsConfigSetting(config, tlsOpt) },
 	}
-	var namespaces map[string]cache.Config
-	if strings.Contains(watchNamespace, ",") {
-		namespaces = map[string]cache.Config{}
-		for _, ns := range strings.Split(watchNamespace, ",") {
-			namespaces[ns] = cache.Config{}
-		}
-	}
 
 	mgrOptions := ctrl.Options{
 		Scheme: scheme,