chore: refactor and coding style (#4120)

zrpc/resolver/internal/kubebuilder.go

@@ -3,7 +3,6 @@ package internal
 import (
 	"context"
 	"fmt"
-	"runtime/debug"
 	"time"
 
 	"github.com/zeromicro/go-zero/core/logx"
@@ -23,18 +22,18 @@ const (
 
 type kubeResolver struct {
 	cc     resolver.ClientConn
-	stopCh chan struct{}
 	inf    informers.SharedInformerFactory
+	stopCh chan struct{}
 }
 
+func (r *kubeResolver) ResolveNow(_ resolver.ResolveNowOptions) {}
+
 func (r *kubeResolver) start() {
 	threading.GoSafe(func() {
 		r.inf.Start(r.stopCh)
 	})
 }
 
-func (r *kubeResolver) ResolveNow(_ resolver.ResolveNowOptions) {}
-
 func (r *kubeResolver) Close() {
 	close(r.stopCh)
 }
@@ -43,8 +42,6 @@ type kubeBuilder struct{}
 
 func (b *kubeBuilder) Build(target resolver.Target, cc resolver.ClientConn,
 	_ resolver.BuildOptions) (resolver.Resolver, error) {
-	logx.Debugf("target: %s, callstack: %s, cc ptr: %p", target, string(debug.Stack()), cc)
-
 	svc, err := kube.ParseTarget(target)
 	if err != nil {
 		return nil, err
@@ -61,10 +58,13 @@ func (b *kubeBuilder) Build(target resolver.Target, cc resolver.ClientConn,
 	}
 
 	if svc.Port == 0 {
-		endpoints, err := cs.CoreV1().Endpoints(svc.Namespace).Get(context.Background(), svc.Name, v1.GetOptions{})
+		// getting endpoints is only to get the port
+		endpoints, err := cs.CoreV1().Endpoints(svc.Namespace).Get(
+			context.Background(), svc.Name, v1.GetOptions{})
 		if err != nil {
 			return nil, err
 		}
+
 		svc.Port = int(endpoints.Subsets[0].Ports[0].Port)
 	}
 
@@ -93,22 +93,24 @@ func (b *kubeBuilder) Build(target resolver.Target, cc resolver.ClientConn,
 		return nil, err
 	}
 
-	endpoints, err := cs.CoreV1().Endpoints(svc.Namespace).Get(context.Background(), svc.Name, v1.GetOptions{})
+	// get the initial endpoints, cannot use the previous endpoints,
+	// because the endpoints may be updated before/after the informer is started.
+	endpoints, err := cs.CoreV1().Endpoints(svc.Namespace).Get(
+		context.Background(), svc.Name, v1.GetOptions{})
 	if err != nil {
 		return nil, err
 	}
 
 	handler.Update(endpoints)
 
-	resolver := &kubeResolver{
+	r := &kubeResolver{
 		cc:     cc,
-		stopCh: make(chan struct{}),
 		inf:    inf,
+		stopCh: make(chan struct{}),
 	}
+	r.start()
 
-	resolver.start()
+	return r, nil
-
-	return resolver, nil
 }
 
 func (b *kubeBuilder) Scheme() string {