add examples/errors (#1077)

* addd examples/errors

examples/errors/api/error_reason.proto

@@ -0,0 +1,17 @@
+syntax = "proto3";
+
+package errors;
+import "errors.proto";
+
+// 多语言特定包名，用于源代码引用
+option go_package = "github.com/go-kratos/kratos/examples/blog/api/v1;v1";
+option java_multiple_files = true;
+option java_package = "blog.v1.errors";
+option objc_class_prefix = "APIBlogErrors";
+
+enum ErrorReason {
+  option (errors.default_code) = 500;
+
+  USER_NOT_FOUND = 0 [(errors.code) = 404];
+  CONTENT_MISSING = 1 [(errors.code) = 400];;
+}

examples/errors/api/errors.proto

@@ -0,0 +1,18 @@
+syntax = "proto3";
+
+package errors;
+
+option go_package = "github.com/go-kratos/kratos/v2/errors;v1";
+option java_multiple_files = true;
+option java_package = "com.github.kratos.errors";
+option objc_class_prefix = "KratosErrors";
+
+import "google/protobuf/descriptor.proto";
+
+extend google.protobuf.EnumOptions {
+  int32 default_code = 1108;
+}
+
+extend google.protobuf.EnumValueOptions {
+  int32 code = 1109;
+}

examples/errors/client/main.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"context"
+	"github.com/go-kratos/kratos/examples/errors/api"
+	"github.com/go-kratos/kratos/v2/errors"
+	"log"
+
+	pb "github.com/go-kratos/kratos/examples/helloworld/helloworld"
+	transgrpc "github.com/go-kratos/kratos/v2/transport/grpc"
+	transhttp "github.com/go-kratos/kratos/v2/transport/http"
+)
+
+func main() {
+	callHTTP()
+	callGRPC()
+}
+
+func callHTTP() {
+	conn, err := transhttp.NewClient(
+		context.Background(),
+		transhttp.WithEndpoint("127.0.0.1:8000"),
+	)
+	if err != nil {
+		panic(err)
+	}
+	client := pb.NewGreeterHTTPClient(conn)
+	reply, err := client.SayHello(context.Background(), &pb.HelloRequest{Name: "empty"})
+	if err != nil {
+		if errors.Code(err) == 500 {
+			log.Println(err)
+		}
+		if api.IsUserNotFound(err) {
+			log.Println("[http] USER_NOT_FOUND_ERROR", err)
+		}
+	} else {
+		log.Printf("[http] SayHello %s\n", reply.Message)
+	}
+}
+
+func callGRPC() {
+	conn, err := transgrpc.DialInsecure(
+		context.Background(),
+		transgrpc.WithEndpoint("127.0.0.1:9000"),
+	)
+	if err != nil {
+		panic(err)
+	}
+	client := pb.NewGreeterClient(conn)
+	reply, err := client.SayHello(context.Background(), &pb.HelloRequest{Name: "kratos"})
+	if err != nil {
+		e := errors.FromError(err)
+		if e.Reason == "USER_NAME_EMPTY" && e.Code == 500 {
+			log.Println("[grpc] USER_NAME_EMPTY", err)
+		}
+		if api.IsUserNotFound(err) {
+			log.Println("[grpc] USER_NOT_FOUND_ERROR", err)
+		}
+	} else {
+		log.Printf("[grpc] SayHello %+v\n", reply)
+	}
+}

examples/errors/server/main.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"github.com/go-kratos/kratos/v2/errors"
+	"log"
+
+	"github.com/go-kratos/kratos/examples/errors/api"
+	"github.com/go-kratos/kratos/examples/helloworld/helloworld"
+	"github.com/go-kratos/kratos/v2"
+	"github.com/go-kratos/kratos/v2/transport/grpc"
+	"github.com/go-kratos/kratos/v2/transport/http"
+)
+
+// go build -ldflags "-X main.Version=x.y.z"
+var (
+	// Name is the name of the compiled software.
+	Name = "errors"
+	// Version is the version of the compiled software.
+	Version = "v1.0.0"
+)
+
+// server is used to implement helloworld.GreeterServer.
+type server struct {
+	helloworld.UnimplementedGreeterServer
+}
+
+// SayHello implements helloworld.GreeterServer
+func (s *server) SayHello(ctx context.Context, in *helloworld.HelloRequest) (*helloworld.HelloReply, error) {
+	fmt.Println(in.Name)
+	if in.Name == "empty" {
+		// Respond to errors through errors.New().
+		return nil, errors.New(500, "USER_NAME_EMPTY", "user name is empty")
+	}
+	if in.Name == "kratos" {
+		// Respond to errors with proto generated code.
+		return nil, api.ErrorUserNotFound("user %s not found", "kratos")
+	}
+	return &helloworld.HelloReply{Message: fmt.Sprintf("Hello %+v", in.Name)}, nil
+}
+
+func main() {
+	s := &server{}
+	grpcSrv := grpc.NewServer(
+		grpc.Address(":9000"),
+	)
+	httpSrv := http.NewServer(
+		http.Address(":8000"),
+	)
+	helloworld.RegisterGreeterServer(grpcSrv, s)
+	helloworld.RegisterGreeterHTTPServer(httpSrv, s)
+
+	app := kratos.New(
+		kratos.Name(Name),
+		kratos.Server(
+			httpSrv,
+			grpcSrv,
+		),
+	)
+
+	if err := app.Run(); err != nil {
+		log.Fatal(err)
+	}
+}