example: errors (#2534)

* Adds readme.

* Fills readme.

* Adds readme.

* Moves error examples.

* Adds port flag.

* Changes the flag for clients.

* Adds package comments.

Author: Can Guler

Diff for: examples/features/deadline/client/main.go

@@ -32,6 +32,8 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+var addr = flag.String("addr", "localhost:50052", "the address to connect to")
+
 func unaryCall(c pb.EchoClient, requestID int, message string, want codes.Code) {
 	// Creates a context with a one second deadline for the RPC.
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
@@ -68,11 +70,9 @@ func streamingCall(c pb.EchoClient, requestID int, message string, want codes.Co
 }
 
 func main() {
-	port := flag.Int("port", 50052, "port number")
 	flag.Parse()
 
-	target := fmt.Sprintf("localhost:%v", *port)
-	conn, err := grpc.Dial(target, grpc.WithInsecure())
+	conn, err := grpc.Dial(*addr, grpc.WithInsecure())
 	if err != nil {
 		log.Fatalf("did not connect: %v", err)
 	}

Diff for: examples/features/errors/README.md

@@ -1 +1,25 @@
-Please see [examples/rpc_errors](../../rpc_errors).
+# Description
+
+This example demonstrates the use of status details in grpc errors.
+
+# Run the sample code
+
+Run the server:
+
+```sh
+$ go run ./server/main.go
+```
+Then run the client in another terminal:
+
+```sh
+$ go run ./client/main.go
+```
+
+It should succeed and print the greeting it received from the server.
+Then run the client again:
+
+```sh
+$ go run ./client/main.go
+```
+
+This time, it should fail by printing error status details that it received from the server.

Diff for: examples/rpc_errors/client/main.go renamed to examples/features/errors/client/main.go

@@ -16,10 +16,12 @@
  *
  */
 
+// Binary client is an example client.
 package main
 
 import (
 	"context"
+	"flag"
 	"log"
 	"os"
 	"time"
@@ -30,9 +32,13 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+var addr = flag.String("addr", "localhost:50052", "the address to connect to")
+
 func main() {
+	flag.Parse()
+
 	// Set up a connection to the server.
-	conn, err := grpc.Dial("localhost:50051", grpc.WithInsecure())
+	conn, err := grpc.Dial(*addr, grpc.WithInsecure())
 	if err != nil {
 		log.Fatalf("did not connect: %v", err)
 	}

Diff for: examples/rpc_errors/server/main.go renamed to examples/features/errors/server/main.go

@@ -16,10 +16,12 @@
  *
  */
 
+// Binary server is an example server.
 package main
 
 import (
 	"context"
+	"flag"
 	"fmt"
 	"log"
 	"net"
@@ -32,9 +34,7 @@ import (
 	"google.golang.org/grpc/status"
 )
 
-const (
-	port = ":50051"
-)
+var port = flag.Int("port", 50052, "port number")
 
 // server is used to implement helloworld.GreeterServer.
 type server struct {
@@ -67,11 +67,14 @@ func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloRe
 }
 
 func main() {
-	log.Printf("server starting on port %s...", port)
-	lis, err := net.Listen("tcp", port)
+	flag.Parse()
+
+	address := fmt.Sprintf(":%v", *port)
+	lis, err := net.Listen("tcp", address)
 	if err != nil {
 		log.Fatalf("failed to listen: %v", err)
 	}
+
 	s := grpc.NewServer()
 	pb.RegisterGreeterServer(s, &server{count: make(map[string]int)})
 	if err := s.Serve(lis); err != nil {