Golang gRPC错误处理方法解析

import (
    "google.golang.org/grpc/codes"
    "google.golang.org/grpc/status"
)

func (s *server) GetUser(ctx context.Context, req *GetUserRequest) (*GetUserResponse, error) {
    if req.Id == "" {
        return nil, status.Error(codes.InvalidArgument, "user ID is required")
    }
    // 模拟用户未找到
    if req.Id == "notexist" {
        return nil, status.Error(codes.NotFound, "user not found")
    }
    return &GetUserResponse{User: &User{Id: req.Id, Name: "Alice"}}, nil
}

func rpcError(err error) error {
    switch {
    case errors.Is(err, ErrUserNotFound):
        return status.Error(codes.NotFound, err.Error())
    case errors.Is(err, ErrInvalidInput):
        return status.Error(codes.InvalidArgument, err.Error())
    default:
        return status.Error(codes.Internal, "internal server error")
    }
}

user, err := s.userService.GetUser(req.Id)
if err != nil {
    return nil, rpcError(err)
}

resp, err := client.GetUser(ctx, &GetUserRequest{Id: "notexist"})
if err != nil {
    st, ok := status.FromError(err)
    if ok {
        switch st.Code() {
        case codes.NotFound:
            log.Printf("用户不存在: %v", st.Message())
        case codes.InvalidArgument:
            log.Printf("参数错误: %v", st.Message())
        default:
            log.Printf("未知错误: %v", st.Message())
        }
    } else {
        log.Printf("非gRPC错误: %v", err)
    }
    return
}
log.Printf("获取用户成功: %+v", resp.User)

st := status.New(codes.InvalidArgument, "字段校验失败")
st, _ = st.WithDetails(&errdetails.BadRequest{
    FieldViolations: []*errdetails.BadRequest_FieldViolation{
        {Field: "email", Description: "无效邮箱格式"},
    },
})
return st.Err()