dataclients/kubernetes: preallocate slices (zalando#2786)

Preallocate some obvious cases found by https://github.com/alexkohler/prealloc

Signed-off-by: Alexander Yastrebov <[email protected]>

Author: AlexanderYastrebov

dataclients/kubernetes/endpoints.go

@@ -31,13 +31,11 @@ func formatEndpoint(a *address, p *port, protocol string) string {
 }
 
 func formatEndpointsForSubsetAddresses(addresses []*address, port *port, protocol string) []string {
-	var result []string
+	result := make([]string, 0, len(addresses))
 	for _, address := range addresses {
 		result = append(result, formatEndpoint(address, port, protocol))
 	}
-
 	return result
-
 }
 
 func (ep *endpoint) targetsByServicePort(protocol string, servicePort *servicePort) []string {

dataclients/kubernetes/endpointslices.go

@@ -55,11 +55,10 @@ func (eps *skipperEndpointSlice) targetsByServicePort(protocol, scheme string, s
 		port = eps.getPort(protocol, servicePort.Name, servicePort.Port)
 	}
 
-	var result []string
+	result := make([]string, 0, len(eps.Endpoints))
 	for _, ep := range eps.Endpoints {
 		result = append(result, formatEndpointString(ep.Address, scheme, port))
 	}
-
 	return result
 }
 
@@ -68,11 +67,10 @@ func (eps *skipperEndpointSlice) targetsByServiceTarget(protocol, scheme string,
 	pValue, _ := serviceTarget.Value.(int)
 	port := eps.getPort(protocol, pName, pValue)
 
-	var result []string
+	result := make([]string, 0, len(eps.Endpoints))
 	for _, ep := range eps.Endpoints {
 		result = append(result, formatEndpointString(ep.Address, scheme, port))
 	}
-
 	return result
 }
 

dataclients/kubernetes/kubernetestest/fixtures.go

@@ -142,7 +142,7 @@ func safeFileClose(t *testing.T, fd *os.File) {
 }
 
 func compileRegexps(s []string) ([]*regexp.Regexp, error) {
-	var r []*regexp.Regexp
+	r := make([]*regexp.Regexp, 0, len(s))
 	for _, si := range s {
 		ri, err := regexp.Compile(si)
 		if err != nil {