preallocate lists

Author: sni

pkg/snclient/check_index.go

@@ -48,7 +48,7 @@ func (l *CheckIndex) Build() *CheckData {
 }
 
 func (l *CheckIndex) Check(_ context.Context, snc *Agent, check *CheckData, _ []Argument) (*CheckResult, error) {
-	keys := make([]string, 0)
+	keys := make([]string, 0, len(AvailableChecks)+len(snc.runSet.cmdAliases)+len(snc.runSet.cmdWraps))
 	for k := range AvailableChecks {
 		keys = append(keys, k)
 	}

pkg/snclient/check_service_linux.go

@@ -285,7 +285,7 @@ func (l *CheckService) parseSystemCtlStatus(name, output string) (listEntry map[
 	}
 	if listEntry["pid"] == "" {
 		matches := reSvcPidCgroup.FindAllStringSubmatch(output, -1)
-		pids := []string{}
+		pids := make([]string, 0, len(matches))
 		for _, m := range matches {
 			pids = append(pids, m[1])
 		}

pkg/snclient/checkdata.go

@@ -241,7 +241,7 @@ func (cd *CheckData) finalizeOutput() (*CheckResult, error) {
 }
 
 func (cd *CheckData) buildListMacros() map[string]string {
-	list := []string{}
+	list := make([]string, 0, len(cd.listData))
 	okList := make([]string, 0)
 	warnList := make([]string, 0)
 	critList := make([]string, 0)
@@ -560,8 +560,8 @@ func (cd *CheckData) sortList(listData []map[string]string, keys []string) []map
 	}
 
 	slices.SortStableFunc(listData, func(a, b map[string]string) int {
-		sortA := []string{}
-		sortB := []string{}
+		sortA := make([]string, 0, len(keys))
+		sortB := make([]string, 0, len(keys))
 		for _, k := range keys {
 			sortA = append(sortA, a[k])
 			sortB = append(sortB, b[k])
@@ -1145,7 +1145,7 @@ func (cd *CheckData) VisitAll(condList ConditionList, callback func(*Condition)
 }
 
 func (cd *CheckData) CloneThreshold(srcThreshold ConditionList) (cloned ConditionList) {
-	cloned = make(ConditionList, 0)
+	cloned = make(ConditionList, 0, len(srcThreshold))
 
 	for i := range srcThreshold {
 		cloned = append(cloned, srcThreshold[i].Clone())

pkg/snclient/checkresult.go

@@ -37,9 +37,10 @@ type CheckResult struct {
 }
 
 func (cr *CheckResult) Finalize(timezone *time.Location, macros ...map[string]string) {
-	macroSet := []map[string]string{{
+	macroSet := make([]map[string]string, 0, len(macros)+1)
+	macroSet = append(macroSet, map[string]string{
 		"status": cr.StateString(),
-	}}
+	})
 	macroSet = append(macroSet, macros...)
 
 	output, err := ReplaceTemplate(cr.Output, timezone, macroSet...)

pkg/snclient/config.go

@@ -604,7 +604,7 @@ func configParseString(val string) (string, error) {
 }
 
 func (config *Config) SectionNames() []string {
-	keys := []string{}
+	keys := make([]string, 0, len(config.sections))
 	for name := range config.sections {
 		keys = append(keys, name)
 	}

pkg/snclient/inventory.go

@@ -98,7 +98,7 @@ func (snc *Agent) buildInventory(ctx context.Context, modules []string) *Invento
 	scripts := make([]string, 0)
 	inventory := make(Inventory)
 
-	keys := make([]string, 0)
+	keys := make([]string, 0, len(AvailableChecks)+len(snc.runSet.cmdAliases)+len(snc.runSet.cmdWraps))
 	for k := range AvailableChecks {
 		keys = append(keys, k)
 	}

pkg/snclient/listen_exporterexporter.go

@@ -174,7 +174,7 @@ func (l *HandlerExporterExporter) readModules(snc *Agent, moduleDir string) (map
 }
 
 func (l *HandlerExporterExporter) JSON() []map[string]string {
-	list := []map[string]string{}
+	list := make([]map[string]string, 0, len(l.modules))
 	ssl := "0"
 	if l.listener.tlsConfig != nil {
 		ssl = "1"

pkg/snclient/snclient_windows.go

@@ -394,7 +394,8 @@ func (snc *Agent) fixPathHoles(cmdAndArgs []string) []string {
 		if err == nil {
 			// can be abs., /usr/bin/echo or %scripts%/check_xy
 			// or rel., echo, timeout, anything in $PATH
-			fixed := []string{realPath}
+			fixed := make([]string, 0, len(cmdAndArgs[pieceNo+1:])+1)
+			fixed = append(fixed, realPath)
 			fixed = append(fixed, cmdAndArgs[pieceNo+1:]...)
 
 			return fixed
@@ -407,7 +408,8 @@ func (snc *Agent) fixPathHoles(cmdAndArgs []string) []string {
 		// try a relative lookup in %scripts%
 		realPath, err = exec.LookPath(filepath.Join(scriptsPath, cmdPath))
 		if err == nil {
-			fixed := []string{realPath}
+			fixed := make([]string, 0, len(cmdAndArgs[pieceNo+1:])+1)
+			fixed = append(fixed, realPath)
 			fixed = append(fixed, cmdAndArgs[pieceNo+1:]...)
 
 			return fixed