Minor fixes/improvements to the spoke submariner agent controllers

pkg/spoke/submarineragent/config_controller.go

@@ -86,7 +86,7 @@ type submarinerConfigController struct {
 	namespace            string
 	cloudProviderFactory cloud.ProviderFactory
 	onSyncDefer          func()
-	knownConfigs         map[string]*configv1alpha1.SubmarinerConfig
+	lastKnownConfig      *configv1alpha1.SubmarinerConfig
 	logger               log.Logger
 }
 
@@ -123,7 +123,6 @@ func NewSubmarinerConfigController(input *SubmarinerConfigControllerInput) facto
 		namespace:            input.Namespace,
 		cloudProviderFactory: input.CloudProviderFactory,
 		onSyncDefer:          input.OnSyncDefer,
-		knownConfigs:         make(map[string]*configv1alpha1.SubmarinerConfig),
 		logger:               log.Logger{Logger: logf.Log.WithName(name)},
 	}
 
@@ -248,8 +247,7 @@ func (c *submarinerConfigController) syncConfig(ctx context.Context, recorder ev
 
 // skipSyncingUnchangedConfig if last submariner config is known and is equal to the given config.
 func (c *submarinerConfigController) skipSyncingUnchangedConfig(config *configv1alpha1.SubmarinerConfig) bool {
-	lastConfig, known := c.knownConfigs[config.Namespace]
-	return known && reflect.DeepEqual(lastConfig.Spec, config.Spec)
+	return c.lastKnownConfig != nil && reflect.DeepEqual(c.lastKnownConfig.Spec, config.Spec)
 }
 
 func (c *submarinerConfigController) prepareForSubmariner(ctx context.Context, config *configv1alpha1.SubmarinerConfig,
@@ -343,7 +341,7 @@ func (c *submarinerConfigController) updateSubmarinerConfigStatus(ctx context.Co
 
 		// When all is well, the status is eventually updated with a "true" condition, allowing us to cache latest good known config
 		if condition.Status == metav1.ConditionTrue {
-			c.knownConfigs[config.Namespace] = config
+			c.lastKnownConfig = config
 		}
 	}
 
@@ -369,19 +367,19 @@ func (c *submarinerConfigController) ensureGateways(ctx context.Context,
 		return failedConditionf("Error retrieving nodes: %v", err), err
 	}
 
-	currentGatewayNames := []string{}
+	currentGatewayNames := make([]string, 0, len(currentGateways))
 	for _, gateway := range currentGateways {
 		currentGatewayNames = append(currentGatewayNames, gateway.Name)
 	}
 
-	updatedGatewayNames := []string{}
+	updatedGatewayNames := make([]string, 0, config.Spec.Gateways)
 
 	requiredGateways := config.Spec.Gateways - len(currentGateways)
 
 	switch {
 	case requiredGateways == 0:
 		// number of gateways unchanged, ensure that the gateways are fully labeled
-		errs := []error{}
+		errs := make([]error, 0, len(currentGateways))
 		for _, gateway := range currentGateways {
 			errs = append(errs, c.labelNode(ctx, config, gateway))
 		}
@@ -520,9 +518,9 @@ func (c *submarinerConfigController) addGateways(ctx context.Context, config *co
 		return []string{}, err
 	}
 
-	names := []string{}
+	names := make([]string, 0, len(gateways))
 
-	errs := []error{}
+	errs := make([]error, 0, len(gateways))
 	for _, gateway := range gateways {
 		errs = append(errs, c.labelNode(ctx, config, gateway))
 		names = append(names, gateway.Name)
@@ -626,7 +624,7 @@ func (c *submarinerConfigController) updateGatewayStatus(ctx context.Context, re
 		return err
 	}
 
-	gatewayNames := []string{}
+	gatewayNames := make([]string, 0, len(gateways))
 	for _, gateway := range gateways {
 		gatewayNames = append(gatewayNames, gateway.Name)
 	}