Pre-alloate slices for better performance

Signed-off-by: Marco Franssen <marco.franssen@gmail.com>

Author: marcofranssen

cmd/doc-gen/main.go

@@ -229,8 +229,6 @@ type Pair struct {
 type KubeTypes []Pair
 
 func ParseDocumentationFrom(src string, dl_name string, shouldSort bool) []KubeTypes {
-	var docForTypes []KubeTypes
-
 	fset := token.NewFileSet()
 	f, err := parser.ParseFile(fset, src, nil, parser.ParseComments)
 	if err != nil {
@@ -258,6 +256,7 @@ func ParseDocumentationFrom(src string, dl_name string, shouldSort bool) []KubeT
 		})
 	}
 
+	docForTypes := make([]KubeTypes, 0, len(types))
 	for _, kubType := range types {
 		structType, _ := kubType.Decl.Specs[0].(*ast.TypeSpec).Type.(*ast.StructType)
 

controllers/fluentbitconfig_controller.go

@@ -247,23 +247,24 @@ func (r *FluentBitConfigReconciler) processNamespacedFluentBitCfgs(
 	[]fluentbitv1alpha2.MultilineParserList, []fluentbitv1alpha2.ClusterMultilineParserList, []string, error,
 ) {
 	var nsCfgs fluentbitv1alpha2.FluentBitConfigList
-	var filters []fluentbitv1alpha2.FilterList
-	var outputs []fluentbitv1alpha2.OutputList
-	var parsers []fluentbitv1alpha2.ParserList
-	var clusterParsers []fluentbitv1alpha2.ClusterParserList
-	var multilineParsers []fluentbitv1alpha2.MultilineParserList
-	var clusterMultilineParsers []fluentbitv1alpha2.ClusterMultilineParserList
-	var rewriteTagConfigs []string
 	// set of rewrite_tag plugin configs to mutate tags for log records coming out of a namespace
 	selector, err := metav1.LabelSelectorAsSelector(&fb.Spec.NamespacedFluentBitCfgSelector)
 	if err != nil {
-		return filters, outputs, parsers, clusterParsers, multilineParsers, clusterMultilineParsers, nil, err
+		return nil, nil, nil, nil, nil, nil, nil, err
 	}
 
 	if err := r.List(ctx, &nsCfgs, client.MatchingLabelsSelector{Selector: selector}); err != nil {
-		return filters, outputs, parsers, clusterParsers, multilineParsers, clusterMultilineParsers, nil, err
+		return nil, nil, nil, nil, nil, nil, nil, err
 	}
 
+	filters := make([]fluentbitv1alpha2.FilterList, 0, len(nsCfgs.Items))
+	outputs := make([]fluentbitv1alpha2.OutputList, 0, len(nsCfgs.Items))
+	parsers := make([]fluentbitv1alpha2.ParserList, 0, len(nsCfgs.Items))
+	clusterParsers := make([]fluentbitv1alpha2.ClusterParserList, 0, len(nsCfgs.Items))
+	multilineParsers := make([]fluentbitv1alpha2.MultilineParserList, 0, len(nsCfgs.Items))
+	clusterMultilineParsers := make([]fluentbitv1alpha2.ClusterMultilineParserList, 0, len(nsCfgs.Items))
+	rewriteTagConfigs := make([]string, 0, len(nsCfgs.Items))
+
 	// Form a slice of list of resources per namespace
 	for _, cfg := range nsCfgs.Items {
 		filterList, outputList, parserList, clusterParserList, multilineParsersList, clusterMultilineParsersList, err := r.ListNamespacedResources(