Allocate array capacity in advance (#2297)

Author: kayrus

pkg/csi/cinder/driver.go

@@ -94,7 +94,10 @@ func NewDriver(endpoint, cluster string) *Driver {
 			csi.ControllerServiceCapability_RPC_LIST_VOLUMES_PUBLISHED_NODES,
 			csi.ControllerServiceCapability_RPC_GET_VOLUME,
 		})
-	d.AddVolumeCapabilityAccessModes([]csi.VolumeCapability_AccessMode_Mode{csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER})
+	d.AddVolumeCapabilityAccessModes(
+		[]csi.VolumeCapability_AccessMode_Mode{
+			csi.VolumeCapability_AccessMode_SINGLE_NODE_WRITER,
+		})
 
 	// ignoring error, because AddNodeServiceCapabilities is public
 	// and so potentially used somewhere else.
@@ -109,7 +112,7 @@ func NewDriver(endpoint, cluster string) *Driver {
 }
 
 func (d *Driver) AddControllerServiceCapabilities(cl []csi.ControllerServiceCapability_RPC_Type) {
-	var csc []*csi.ControllerServiceCapability
+	csc := make([]*csi.ControllerServiceCapability, 0, len(cl))
 
 	for _, c := range cl {
 		klog.Infof("Enabling controller service capability: %v", c.String())
@@ -120,22 +123,28 @@ func (d *Driver) AddControllerServiceCapabilities(cl []csi.ControllerServiceCapa
 }
 
 func (d *Driver) AddVolumeCapabilityAccessModes(vc []csi.VolumeCapability_AccessMode_Mode) []*csi.VolumeCapability_AccessMode {
-	var vca []*csi.VolumeCapability_AccessMode
+	vca := make([]*csi.VolumeCapability_AccessMode, 0, len(vc))
+
 	for _, c := range vc {
 		klog.Infof("Enabling volume access mode: %v", c.String())
 		vca = append(vca, NewVolumeCapabilityAccessMode(c))
 	}
+
 	d.vcap = vca
+
 	return vca
 }
 
 func (d *Driver) AddNodeServiceCapabilities(nl []csi.NodeServiceCapability_RPC_Type) error {
-	var nsc []*csi.NodeServiceCapability
+	nsc := make([]*csi.NodeServiceCapability, 0, len(nl))
+
 	for _, n := range nl {
 		klog.Infof("Enabling node service capability: %v", n.String())
 		nsc = append(nsc, NewNodeServiceCapability(n))
 	}
+
 	d.nscap = nsc
+
 	return nil
 }
 
@@ -149,6 +158,7 @@ func (d *Driver) ValidateControllerServiceRequest(c csi.ControllerServiceCapabil
 			return nil
 		}
 	}
+
 	return status.Error(codes.InvalidArgument, c.String())
 }
 

pkg/csi/manila/driver.go

@@ -170,7 +170,7 @@ func NewDriver(o *DriverOpts) (*Driver, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to initialize proxied CSI driver: %v", err)
 	}
-	var nscaps []csi.NodeServiceCapability_RPC_Type
+	nscaps := make([]csi.NodeServiceCapability_RPC_Type, 0, len(nodeCapsMap))
 	for c := range nodeCapsMap {
 		nscaps = append(nscaps, c)
 
@@ -195,7 +195,7 @@ func (d *Driver) Run() {
 }
 
 func (d *Driver) addControllerServiceCapabilities(cs []csi.ControllerServiceCapability_RPC_Type) {
-	var caps []*csi.ControllerServiceCapability
+	caps := make([]*csi.ControllerServiceCapability, 0, len(cs))
 
 	for _, c := range cs {
 		klog.Infof("Enabling controller service capability: %v", c.String())
@@ -214,7 +214,7 @@ func (d *Driver) addControllerServiceCapabilities(cs []csi.ControllerServiceCapa
 }
 
 func (d *Driver) addVolumeCapabilityAccessModes(vs []csi.VolumeCapability_AccessMode_Mode) {
-	var caps []*csi.VolumeCapability_AccessMode
+	caps := make([]*csi.VolumeCapability_AccessMode, 0, len(vs))
 
 	for _, c := range vs {
 		klog.Infof("Enabling volume access mode: %v", c.String())
@@ -225,7 +225,7 @@ func (d *Driver) addVolumeCapabilityAccessModes(vs []csi.VolumeCapability_Access
 }
 
 func (d *Driver) addNodeServiceCapabilities(ns []csi.NodeServiceCapability_RPC_Type) {
-	var caps []*csi.NodeServiceCapability
+	caps := make([]*csi.NodeServiceCapability, 0, len(ns))
 
 	for _, c := range ns {
 		klog.Infof("Enabling node service capability: %v", c.String())

pkg/identity/keystone/authenticator.go

@@ -71,7 +71,7 @@ func (k *Keystoner) GetTokenInfo(token string) (*tokenInfo, error) {
 		return nil, fmt.Errorf("failed to extract roles information from Keystone response: %v", err)
 	}
 
-	var userRoles []string
+	userRoles := make([]string, 0, len(roles))
 	for _, role := range roles {
 		userRoles = append(userRoles, role.Name)
 	}
@@ -90,19 +90,18 @@ func (k *Keystoner) GetTokenInfo(token string) (*tokenInfo, error) {
 // revive:enable:unexported-return
 
 func (k *Keystoner) GetGroups(token string, userID string) ([]string, error) {
-	var userGroups []string
-
 	k.client.ProviderClient.SetToken(token)
 	allGroupPages, err := users.ListGroups(k.client, userID).AllPages()
 	if err != nil {
-		return userGroups, fmt.Errorf("failed to get user groups from Keystone: %v", err)
+		return nil, fmt.Errorf("failed to get user groups from Keystone: %v", err)
 	}
 
 	allGroups, err := groups.ExtractGroups(allGroupPages)
 	if err != nil {
-		return userGroups, fmt.Errorf("failed to extract user groups from Keystone response: %v", err)
+		return nil, fmt.Errorf("failed to extract user groups from Keystone response: %v", err)
 	}
 
+	userGroups := make([]string, 0, len(allGroups))
 	for _, g := range allGroups {
 		userGroups = append(userGroups, g.Name)
 	}

pkg/identity/keystone/keystone.go

@@ -337,6 +337,7 @@ func (k *Auth) authorizeToken(w http.ResponseWriter, r *http.Request, data map[s
 	attrs := authorizer.AttributesRecord{User: usr}
 
 	groups := spec["group"].([]interface{})
+	usr.Groups = make([]string, 0, len(groups))
 	for _, v := range groups {
 		usr.Groups = append(usr.Groups, v.(string))
 	}

pkg/ingress/controller/openstack/octavia.go

@@ -122,7 +122,7 @@ func NewResourceTracker(ingressName string, client *gophercloud.ServiceClient, l
 
 	logger := log.WithFields(log.Fields{"ingress": ingressName, "lbID": lbID})
 
-	var oldPoolIDs []string
+	oldPoolIDs := make([]string, 0, len(oldPoolMapping))
 	for _, poolID := range oldPoolMapping {
 		oldPoolIDs = append(oldPoolIDs, poolID)
 	}
@@ -181,7 +181,7 @@ func (rt *ResourceTracker) CreateResources() error {
 		rt.logger.WithFields(log.Fields{"poolName": pool.Name, "poolID": poolID}).Info("pool members updated ")
 	}
 
-	var curPoolIDs []string
+	curPoolIDs := make([]string, 0, len(poolMapping))
 	for _, id := range poolMapping {
 		curPoolIDs = append(curPoolIDs, id)
 	}

pkg/openstack/instances.go

@@ -633,7 +633,7 @@ func nodeAddresses(srv *servers.Server, ports []ports.Port, networkingOpts Netwo
 		return nil, err
 	}
 
-	var networks []string
+	networks := make([]string, 0, len(addresses))
 	for k := range addresses {
 		networks = append(networks, k)
 	}

pkg/openstack/routes.go

@@ -82,7 +82,7 @@ func (r *Routes) ListRoutes(ctx context.Context, clusterName string) ([]*cloudpr
 		return nil, err
 	}
 
-	var routes []*cloudprovider.Route
+	routes := make([]*cloudprovider.Route, 0, len(router.Routes))
 	for _, item := range router.Routes {
 		nodeName, foundNode := getNodeNameByAddr(item.NextHop, nodes)
 		route := cloudprovider.Route{