preallocating slices (#904)

* preallocated some slices when size is known

* gofmt

* gofmt

network/service/handler/handler.go

@@ -171,7 +171,7 @@ func (n *Network) Routes(ctx context.Context, req *pbNet.RoutesRequest, resp *pb
 		return errors.InternalServerError("go.micro.network", "failed to list routes: %s", err)
 	}
 
-	var respRoutes []*pbRtr.Route
+	respRoutes := make([]*pbRtr.Route, 0, len(routes))
 	for _, route := range routes {
 		respRoute := &pbRtr.Route{
 			Service: route.Service,

proxy/mucp/mucp.go

@@ -95,7 +95,7 @@ func toNodes(routes []router.Route) []string {
 }
 
 func toSlice(r map[uint64]router.Route) []router.Route {
-	var routes []router.Route
+	routes := make([]router.Route, 0, len(r))
 	for _, v := range r {
 		routes = append(routes, v)
 	}
@@ -224,7 +224,7 @@ func (p *Proxy) cacheRoutes(service string) ([]router.Route, error) {
 // refreshMetrics will refresh any metrics for our local cached routes.
 // we may not receive new watch events for these as they change.
 func (p *Proxy) refreshMetrics() {
-	var services []string
+	services := make([]string, 0, len(p.Routes))
 
 	// get a list of services to update
 	p.RLock()

registry/service/service.go

@@ -89,7 +89,7 @@ func (s *serviceRegistry) GetService(name string) ([]*registry.Service, error) {
 		return nil, err
 	}
 
-	var services []*registry.Service
+	services := make([]*registry.Service, 0, len(rsp.Services))
 	for _, service := range rsp.Services {
 		services = append(services, ToService(service))
 	}
@@ -102,7 +102,7 @@ func (s *serviceRegistry) ListServices() ([]*registry.Service, error) {
 		return nil, err
 	}
 
-	var services []*registry.Service
+	services := make([]*registry.Service, 0, len(rsp.Services))
 	for _, service := range rsp.Services {
 		services = append(services, ToService(service))
 	}

store/cloudflare/cloudflare.go

@@ -123,7 +123,7 @@ func (w *workersKV) List() ([]*store.Record, error) {
 		return nil, errors.New(messages)
 	}
 
-	var keys []string
+	keys := make([]string, 0, len(a.Result))
 
 	for _, r := range a.Result {
 		keys = append(keys, r.Name)

store/etcd/etcd.go

@@ -32,7 +32,7 @@ func (e *ekv) Read(keys ...string) ([]*store.Record, error) {
 		values = append(values, keyval.Kvs...)
 	}
 
-	var records []*store.Record
+	records := make([]*store.Record, 0, len(values))
 
 	for _, kv := range values {
 		records = append(records, &store.Record{

tunnel/default.go

@@ -1186,7 +1186,7 @@ func (t *tun) Links() []Link {
 	t.RLock()
 	defer t.RUnlock()
 
-	var links []Link
+	links := make([]Link, 0, len(t.links))
 
 	for _, link := range t.links {
 		links = append(links, link)