all: preallocate slices with known size

pkg/azure/api/api.go

@@ -278,7 +278,7 @@ func (c *Client) GetVpcsAndSubnets(ctx context.Context) (ipamTypes.VirtualNetwor
 // the interfaceID. The provided IPs must belong to the subnet as specified by
 // the subnet ID.
 func (c *Client) AssignPrivateIpAddresses(ctx context.Context, subnetID, interfaceID string, ips []net.IP) error {
-	var ipConfigurations []network.InterfaceIPConfiguration
+	ipConfigurations := make([]network.InterfaceIPConfiguration, 0, len(ips))
 
 	for _, ip := range ips {
 		ipString := ip.String()

pkg/checker/checker.go

@@ -105,7 +105,7 @@ func DeepAllowUnexported(vs ...interface{}) cmp.Option {
 	for _, v := range vs {
 		structTypes(reflect.ValueOf(v), m)
 	}
-	var typs []interface{}
+	typs := make([]interface{}, 0, len(m))
 	for t := range m {
 		typs = append(typs, reflect.New(t).Elem().Interface())
 	}

pkg/endpoint/restore_test.go

@@ -145,7 +145,7 @@ func (ds *EndpointSuite) TestReadEPsFromDirNames(c *C) {
 	c.Assert(len(eps), Equals, len(epsWanted))
 
 	sort.Slice(epsWanted, func(i, j int) bool { return epsWanted[i].ID < epsWanted[j].ID })
-	var restoredEPs []*Endpoint
+	restoredEPs := make([]*Endpoint, 0, len(eps))
 	for _, ep := range eps {
 		restoredEPs = append(restoredEPs, ep)
 	}

pkg/fqdn/name_manager.go

@@ -64,15 +64,12 @@ func (n *NameManager) GetModel() *models.NameManager {
 	n.Mutex.Lock()
 	defer n.Mutex.Unlock()
 
-	var (
-		namesToPoll  []string
-		allSelectors []*models.SelectorEntry
-	)
-
+	namesToPoll := make([]string, 0, len(n.namesToPoll))
 	for name := range n.namesToPoll {
 		namesToPoll = append(namesToPoll, name)
 	}
 
+	allSelectors := make([]*models.SelectorEntry, 0, len(n.allSelectors))
 	for fqdnSel, regex := range n.allSelectors {
 		pair := &models.SelectorEntry{
 			SelectorString: fqdnSel.String(),

pkg/ip/ip.go

@@ -194,7 +194,6 @@ func getNetworkPrefix(ipNet *net.IPNet) *net.IP {
 }
 
 func removeCIDR(allowCIDR, removeCIDR *net.IPNet) ([]*net.IPNet, error) {
-	var allows []*net.IPNet
 	var allowIsIpv4, removeIsIpv4 bool
 	var allowBitLen int
 
@@ -240,6 +239,7 @@ func removeCIDR(allowCIDR, removeCIDR *net.IPNet) ([]*net.IPNet, error) {
 	// Create CIDR prefixes with mask size of Y+1, Y+2 ... X where Y is the mask
 	// length of the CIDR prefix B from which we are excluding a CIDR prefix A
 	// with mask length X.
+	allows := make([]*net.IPNet, 0, removeSize-allowSize)
 	for i := (allowBitLen - allowSize - 1); i >= (allowBitLen - removeSize); i-- {
 		// The mask for each CIDR prefix is simply the ith bit flipped, and then
 		// zero'ing out all subsequent bits (the host identifier part of the

pkg/ipam/allocator/pool_allocator.go

@@ -54,7 +54,7 @@ func (s *PoolAllocator) Allocate(ip net.IP) error {
 // AllocateMany allocates multiple IP addresses. The operation succeeds if all
 // IPs can be allocated. On failure, all IPs are released again.
 func (s *PoolAllocator) AllocateMany(num int) ([]net.IP, error) {
-	var ips []net.IP
+	ips := make([]net.IP, 0, num)
 
 	for i := 0; i < num; i++ {
 		ip, err := s.allocator.AllocateNext()

pkg/ipcache/cidr.go

@@ -54,10 +54,10 @@ func AllocateCIDRsForIPs(prefixes []net.IP) ([]*identity.Identity, error) {
 
 func allocateCIDRs(prefixes []*net.IPNet) ([]*identity.Identity, error) {
 	// maintain list of used identities to undo on error
-	var usedIdentities []*identity.Identity
+	usedIdentities := make([]*identity.Identity, 0, len(prefixes))
 
 	// maintain list of newly allocated identities to update ipcache
-	allocatedIdentities := map[string]*identity.Identity{}
+	allocatedIdentities := make(map[string]*identity.Identity, len(prefixes))
 	newlyAllocatedIdentities := map[string]*identity.Identity{}
 
 	for _, prefix := range prefixes {

pkg/k8s/watchers/watcher.go

@@ -617,7 +617,7 @@ func genCartesianProduct(
 	bes *k8s.Endpoints,
 ) []loadbalancer.SVC {
 
-	var svcs []loadbalancer.SVC
+	svcs := make([]loadbalancer.SVC, 0, len(ports))
 
 	for fePortName, fePort := range ports {
 		var besValues []loadbalancer.Backend

pkg/labels/labels.go

@@ -442,7 +442,7 @@ func (l Label) FormatForKVStore() string {
 // DO NOT BREAK THE FORMAT OF THIS. THE RETURNED STRING IS USED AS KEY IN
 // THE KEY-VALUE STORE.
 func (l Labels) SortedList() []byte {
-	var keys []string
+	keys := make([]string, 0, len(l))
 	for k := range l {
 		keys = append(keys, k)
 	}

pkg/policy/visibility_test.go

@@ -34,7 +34,7 @@ func (ds *PolicyTestSuite) TestGenerateL7RulesByParser(c *C) {
 	c.Assert(m, Not(IsNil))
 	c.Assert(len(m), Equals, 1)
 
-	var l7Rules []*PerSelectorPolicy
+	l7Rules := make([]*PerSelectorPolicy, 0, len(m))
 	for _, v := range m {
 		l7Rules = append(l7Rules, v)
 	}

pkg/service/service_test.go

@@ -237,7 +237,7 @@ func (m *ManagerTestSuite) TestHealthCheckNodePort(c *C) {
 
 func (m *ManagerTestSuite) TestGetServiceNameByAddr(c *C) {
 	fe := frontend1.DeepCopy()
-	var be []lb.Backend
+	be := make([]lb.Backend, 0, len(backends1))
 	for _, backend := range backends1 {
 		be = append(be, *backend.DeepCopy())
 	}