examples: add error_handling example; move errors to error_details (#…

…6293)

examples/examples_test.sh

@@ -57,7 +57,8 @@ EXAMPLES=(
     "features/compression"
     "features/deadline"
     "features/encryption/TLS"
-    "features/errors"
+    "features/error_details"
+    "features/error_handling"
     "features/interceptor"
     "features/load_balancing"
     "features/metadata"
@@ -109,7 +110,8 @@ declare -A EXPECTED_SERVER_OUTPUT=(
     ["features/compression"]="UnaryEcho called with message \"compress\""
     ["features/deadline"]=""
     ["features/encryption/TLS"]=""
-    ["features/errors"]=""
+    ["features/error_details"]=""
+    ["features/error_handling"]=""
     ["features/interceptor"]="unary echoing message \"hello world\""
     ["features/load_balancing"]="serving on :50051"
     ["features/metadata"]="message:\"this is examples/metadata\", sending echo"
@@ -130,7 +132,8 @@ declare -A EXPECTED_CLIENT_OUTPUT=(
     ["features/compression"]="UnaryEcho call returned \"compress\", <nil>"
     ["features/deadline"]="wanted = DeadlineExceeded, got = DeadlineExceeded"
     ["features/encryption/TLS"]="UnaryEcho:  hello world"
-    ["features/errors"]="Greeting: Hello world"
+    ["features/error_details"]="Greeting: Hello world"
+    ["features/error_handling"]="Received error"
     ["features/interceptor"]="UnaryEcho:  hello world"
     ["features/load_balancing"]="calling helloworld.Greeter/SayHello with pick_first"
     ["features/metadata"]="this is examples/metadata"

examples/features/error_handling/README.md

@@ -0,0 +1,22 @@
+# Description
+
+This example demonstrates basic RPC error handling in gRPC.
+
+# Run the sample code
+
+Run the server, which returns an error if the RPC request's `Name` field is
+empty.
+
+```sh
+$ go run ./server/main.go
+```
+
+Then run the client in another terminal, which does two requests: one with an
+empty Name field and one with it populated with the current username provided by
+os/user.
+
+```sh
+$ go run ./client/main.go
+```
+
+It should print the status codes it received from the server.

examples/features/error_handling/client/main.go

@@ -0,0 +1,70 @@
+/*
+ *
+ * Copyright 2023 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Binary client is an example client.
+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"os/user"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials/insecure"
+	pb "google.golang.org/grpc/examples/helloworld/helloworld"
+	"google.golang.org/grpc/status"
+)
+
+var addr = flag.String("addr", "localhost:50052", "the address to connect to")
+
+func main() {
+	flag.Parse()
+
+	name := "unknown"
+	if u, err := user.Current(); err == nil && u.Username != "" {
+		name = u.Username
+	}
+
+	// Set up a connection to the server.
+	conn, err := grpc.Dial(*addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		log.Fatalf("Failed to connect: %v", err)
+	}
+	defer conn.Close()
+	c := pb.NewGreeterClient(conn)
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	for _, reqName := range []string{"", name} {
+		log.Printf("Calling SayHello with Name:%q", reqName)
+		r, err := c.SayHello(ctx, &pb.HelloRequest{Name: reqName})
+		if err != nil {
+			if status.Code(err) != codes.InvalidArgument {
+				log.Printf("Received unexpected error: %v", err)
+				continue
+			}
+			log.Printf("Received error: %v", err)
+			continue
+		}
+		log.Printf("Received response: %s", r.Message)
+	}
+}

examples/features/error_handling/server/main.go

@@ -0,0 +1,65 @@
+/*
+ *
+ * Copyright 2023 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Binary server is an example server.
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	pb "google.golang.org/grpc/examples/helloworld/helloworld"
+)
+
+var port = flag.Int("port", 50052, "port number")
+
+// server is used to implement helloworld.GreeterServer.
+type server struct {
+	pb.UnimplementedGreeterServer
+}
+
+// SayHello implements helloworld.GreeterServer.
+func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
+	if in.Name == "" {
+		return nil, status.Errorf(codes.InvalidArgument, "request missing required field: Name")
+	}
+	return &pb.HelloReply{Message: "Hello " + in.Name}, nil
+}
+
+func main() {
+	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{})
+	if err := s.Serve(lis); err != nil {
+		log.Fatalf("failed to serve: %v", err)
+	}
+}