客户端

---

业务网关相当于gRPC客户端，各个微服务相当于gRPC服务端。我们将在控制器属性里，定义gRPC client，供后续使用。

定义client由grpcx.Client.MustNewGrpcClientConn(service, opts...)完成。

app/gateway/internal/controller/user/user_new.go

package user  
  
import (  
    "github.com/gogf/gf/contrib/rpc/grpcx/v2"  
    "proxima/app/gateway/api/user"
    v1 "proxima/app/user/api/account/v1"  
)  
  
type ControllerV1 struct {  
    AccountClient v1.AccountClient  
}  
  
func NewV1() user.IUserV1 {  
    var conn = grpcx.Client.MustNewGrpcClientConn("user")  
  
    return &ControllerV1{  
       AccountClient: v1.NewAccountClient(conn),  
    }  
}

app/gateway/internal/controller/words/words_new.go

package words  
  
import (  
    "github.com/gogf/gf/contrib/rpc/grpcx/v2"  
    "proxima/app/gateway/api/words"
    v1 "proxima/app/word/api/words/v1"  
)  
  
type ControllerV1 struct {  
    WordsClient v1.WordsClient  
}  
  
func NewV1() words.IWordsV1 {  
    var conn = grpcx.Client.MustNewGrpcClientConn("word")  
  
    return &ControllerV1{  
       WordsClient: v1.NewWordsClient(conn),  
    }  
}

拦截器

---

当前客户端没有超时处理，gRPC的默认超时时间阈值又非常大。如果gRPC服务端、etcd服务，或者网络出现异常，业务网关会无限卡死。我们来添加超时拦截器，以应对这种情况。

定义拦截器

超时机制很简单，通过Go的上下文提供。

app/gateway/utility/grpc.go

package utility  
  
import (  
    "context"  
    "time"  
    "google.golang.org/grpc"
)  
  
func GrpcClientTimeout(ctx context.Context, method string, req, reply interface{},  
    cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption,  
) error {  
    ctx, cancel := context.WithTimeout(ctx, 3*time.Second)  
    defer cancel()  
  
    err := invoker(ctx, method, req, reply, cc, opts...)  
    return err  
}

调用拦截器

app/gateway/internal/controller/user/user_new.go

package user  
  
import (  
    "github.com/gogf/gf/contrib/rpc/grpcx/v2"  
    "proxima/app/gateway/api/user"
    "proxima/app/gateway/utility"
    v1 "proxima/app/user/api/account/v1"  
)  
  
type ControllerV1 struct {  
    AccountClient v1.AccountClient  
}  
  
func NewV1() user.IUserV1 {  
    var conn = grpcx.Client.MustNewGrpcClientConn("user", grpcx.Client.ChainUnary( 
        utility.GrpcClientTimeout,  
    ))  
  
    return &ControllerV1{  
       AccountClient: v1.NewAccountClient(conn),  
    }  
}

app/gateway/internal/controller/words/words_new.go

package words  
  
import (  
    "github.com/gogf/gf/contrib/rpc/grpcx/v2"  
    "proxima/app/gateway/api/words"
    "proxima/app/gateway/utility"
    v1 "proxima/app/word/api/words/v1"  
)  
  
type ControllerV1 struct {  
    WordsClient v1.WordsClient  
}  
  
func NewV1() words.IWordsV1 {  
    var conn = grpcx.Client.MustNewGrpcClientConn("word", grpcx.Client.ChainUnary( 
        utility.GrpcClientTimeout,  
    ))
  
    return &ControllerV1{  
       WordsClient: v1.NewWordsClient(conn),  
    }  
}