comments and things

examples/features/name_resolving/client/main.go

@@ -16,6 +16,7 @@
  *
  */
 
+// Binary client is an example client.
 package main
 
 import (
@@ -36,8 +37,6 @@ const (
 	backendAddr = "localhost:50051"
 )
 
-var addrs = []string{backendAddr}
-
 func callUnaryEcho(c ecpb.EchoClient, message string) {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
@@ -65,7 +64,7 @@ func main() {
 	}
 	defer passthroughConn.Close()
 
-	fmt.Println("--- calling helloworld.Greeter/SayHello with pick_first ---")
+	fmt.Printf("--- calling helloworld.Greeter/SayHello to \"passthrough:///%s\"\n", backendAddr)
 	makeRPCs(passthroughConn, 10)
 
 	fmt.Println()
@@ -79,27 +78,39 @@ func main() {
 	}
 	defer exampleConn.Close()
 
-	fmt.Println("--- calling helloworld.Greeter/SayHello with pick_first ---")
+	fmt.Printf("--- calling helloworld.Greeter/SayHello to \"%s:///%s\"\n", exampleScheme, exampleServiceName)
 	makeRPCs(exampleConn, 10)
 }
 
-// Following is an example name resolver implementation.
-
+// Following is an example name resolver. It includes a
+// ResolverBuilder(https://godoc.org/google.golang.org/grpc/resolver#Builder)
+// and a Resolver(https://godoc.org/google.golang.org/grpc/resolver#Resolver).
+//
+// A ResolverBuilder is registered for a scheme (in this example, "example" is
+// the scheme). When a ClientConn is created for this scheme, the
+// ResolverBuilder will be picked to build a Resolver. Note that a new Resolver
+// is built for each ClientConn. The Resolver will watch the updates for the
+// target, and send updates to the ClientConn.
+
+// exampleResolverBuilder is a
+// ResolverBuilder(https://godoc.org/google.golang.org/grpc/resolver#Builder).
 type exampleResolverBuilder struct{}
 
 func (*exampleResolverBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
 	r := &exampleResolver{
 		target: target,
 		cc:     cc,
 		addrsStore: map[string][]string{
-			exampleServiceName: addrs,
+			exampleServiceName: []string{backendAddr},
 		},
 	}
 	r.start()
 	return r, nil
 }
 func (*exampleResolverBuilder) Scheme() string { return exampleScheme }
 
+// exampleResolver is a
+// Resolver(https://godoc.org/google.golang.org/grpc/resolver#Resolver).
 type exampleResolver struct {
 	target     resolver.Target
 	cc         resolver.ClientConn
@@ -118,5 +129,7 @@ func (*exampleResolver) ResolveNow(o resolver.ResolveNowOption) {}
 func (*exampleResolver) Close()                                 {}
 
 func init() {
+	// Register the example ResolverBuilder. This is usually done in a package's
+	// init() function.
 	resolver.Register(&exampleResolverBuilder{})
 }

examples/features/name_resolving/server/main.go

@@ -16,24 +16,22 @@
  *
  */
 
+// Binary server is an example server.
 package main
 
 import (
 	"context"
 	"fmt"
 	"log"
 	"net"
-	"sync"
 
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	ecpb "google.golang.org/grpc/examples/features/proto/echo"
 	"google.golang.org/grpc/status"
 )
 
-var (
-	addrs = []string{":50051"}
-)
+const addr = "localhost:50051"
 
 type ecServer struct {
 	addr string
@@ -53,6 +51,9 @@ func (s *ecServer) BidirectionalStreamingEcho(ecpb.Echo_BidirectionalStreamingEc
 }
 
 func startServer(addr string) {
+}
+
+func main() {
 	lis, err := net.Listen("tcp", addr)
 	if err != nil {
 		log.Fatalf("failed to listen: %v", err)
@@ -64,15 +65,3 @@ func startServer(addr string) {
 		log.Fatalf("failed to serve: %v", err)
 	}
 }
-
-func main() {
-	var wg sync.WaitGroup
-	for _, addr := range addrs {
-		wg.Add(1)
-		go func(addr string) {
-			defer wg.Done()
-			startServer(addr)
-		}(addr)
-	}
-	wg.Wait()
-}