servicerd/util/clientutil.go

/**
客户端封装
*/
package util

import (
	"app.yhyue.com/BP/servicerd/proto"
	"context"
	"errors"
	"google.golang.org/grpc"
	"log"
	"time"
)

const (
	//TODO 目前实现前2中
	ERROR_ERTRY_TYPE_FIRST    = iota //1次，找到第一个服务提供者，出错即返回
	ERROR_ERTRY_TYPE_FIRST_5         //5次尝试，找到第一个服务提供者
	ERROR_ERTRY_TYPE_OVER_ALL        //尝试遍历所有服务，直至又一个提供正常返回
)

//调用
type CallFn func(conn *grpc.ClientConn, args ...interface{}) (interface{}, error)

type ClientUtil struct {
	RdServer      string
	serviceConn   *grpc.ClientConn
	serviceClient proto.ServiceClient
}

func NewClient(rdServer string) (*ClientUtil, error) {
	c := &ClientUtil{RdServer: rdServer}
	conn, err := grpc.Dial(rdServer, grpc.WithInsecure())
	if err != nil {
		return nil, err
	}
	client := proto.NewServiceClient(conn)
	c.serviceConn = conn
	c.serviceClient = client
	return c, nil
}

func (cu *ClientUtil) Run(serviceName string, errRetryTime int, fn CallFn, args ...interface{}) (interface{}, error) {
	defer func() {
		if err := recover(); err != nil {
			log.Println("捕获异常:", err)
		}
	}()
	for i := 0; i < errRetryTime; i++ {
		repl, err := cu.serviceClient.Apply(context.Background(), &proto.ApplyReqData{Name: serviceName, Balance: 0})
		if err != nil {
			log.Println("client-util", "无可用服务", err.Error())
			time.Sleep(1 * time.Second)
			continue
		}
		//TODO 业务调用
		conn, err := grpc.Dial(repl.Addr, grpc.WithInsecure())
		if err != nil {
			log.Println("client-util", "连接到服务节点失败：", repl.Addr, err.Error())
			time.Sleep(1 * time.Second)
			continue
		}
		ret, err := fn(conn, args...)
		conn.Close()
		return ret, err
	}
	return nil, errors.New("远程服务调用失败")
}