extract configuration to buildNatsConfig method

internal/controller/jetstream_controller.go

@@ -25,6 +25,7 @@ type JetStreamController interface {
 
 	// ReadOnly returns true when no changes should be made by the controller.
 	ReadOnly() bool
+
 	// ValidNamespace ok if the controllers namespace restriction allows the given namespace.
 	ValidNamespace(string string) bool
 
@@ -62,16 +63,30 @@ func (c *jsController) ValidNamespace(targetNamespace string) bool {
 }
 
 func (c *jsController) WithJetStreamClient(opts *connectionOptions, op func(js jetstream.JetStream) error) error {
+
 	// Build single use client
-	// TODO(future feature): Use client-pool
-	serverUrl := strings.Join(opts.Servers, ",")
+	// TODO(future-feature): Use client-pool instead of single use client
+	cfg := c.buildNatsConfig(opts)
+
+	jsClient, closer, err := CreateJetStreamClient(cfg, true)
+	if err != nil {
+		return fmt.Errorf("create jetstream client: %w", err)
+	}
+	defer closer.Close()
+
+	return op(jsClient)
+}
+
+// buildNatsConfig uses given opts to override the base NatsConfig.
+func (c *jsController) buildNatsConfig(opts *connectionOptions) *NatsConfig {
 
-	// Build nats config from opts and controller base config.
-	// Takes opts values if present.
+	serverUrls := strings.Join(opts.Servers, ",")
+
+	// Takes opts values if present
 	cfg := &NatsConfig{
 		CRDConnect: false,
 		ClientName: c.config.ClientName,
-		ServerURL:  or(serverUrl, c.config.ServerURL),
+		ServerURL:  or(serverUrls, c.config.ServerURL),
 		TLSFirst:   c.config.TLSFirst, // TODO(review): should this value depend on any opts? There is no TLSFirst in the spec
 	}
 
@@ -95,13 +110,7 @@ func (c *jsController) WithJetStreamClient(opts *connectionOptions, op func(js j
 		cfg.Key = c.config.Key
 	}
 
-	client, closer, err := CreateJetStreamClient(cfg, true)
-	if err != nil {
-		return fmt.Errorf("create jetstream client: %w", err)
-	}
-	defer closer.Close()
-
-	return op(client)
+	return cfg
 }
 
 // or returns the value if it is not the null value. Otherwise, the fallback value is returned
@@ -112,7 +121,7 @@ func or[T comparable](v T, fallback T) T {
 	return v
 }
 
-// updateReadyCondition returns the conditions with an added or updated ready condition
+// updateReadyCondition returns the given conditions with an added or updated ready condition.
 func updateReadyCondition(conditions []api.Condition, status v1.ConditionStatus, reason string, message string) []api.Condition {
 
 	var currentStatus v1.ConditionStatus