Sentinel-Go：2.Sentinel-Go的基本使用（二）流控规则持久化

谁践踏了优雅 2023-01-13 11:59 178阅读 0赞

# 1.教程 #

在[Sentinel-Go：1.Sentinel-Go的基本使用（一）流控规则][Sentinel-Go_1.Sentinel-Go]中，已经创建好了module：sentinel-go-sample，我们继续以它为例来演示`流控规则持久化`。

## 1.1 先在Nacos配置中心添加配置文件 ##

1.  Nacos的安装部署，请参考：[Nacos：1.Nacos的基本使用（一）服务注册与发现][Nacos_1.Nacos]
2.  添加配置文件

![image][]

1.  配置文件内容示例：

sentinel-go-sample-sentinel-flow

[
        { 
            "resource": "testFlowRule",
            "tokenCalculateStrategy": 0,
            "controlBehavior": 0,
            "threshold": 2,
            "statIntervalInMs": 1000
        }
    ]

## 1.2 修改qps\_limit\_example.go ##

qps\_limit\_example.go

package main
    
    import (
    	"fmt"
    	sentinel "github.com/alibaba/sentinel-golang/api"
    	"github.com/alibaba/sentinel-golang/core/base"
    	"github.com/alibaba/sentinel-golang/core/config"
    	"github.com/alibaba/sentinel-golang/core/flow"
    	"github.com/alibaba/sentinel-golang/ext/datasource"
    	"github.com/alibaba/sentinel-golang/logging"
    	"github.com/alibaba/sentinel-golang/pkg/datasource/nacos"
    	"github.com/nacos-group/nacos-sdk-go/clients"
    	"github.com/nacos-group/nacos-sdk-go/common/constant"
    	"log"
    	"net/http"
    	"runtime"
    	"strings"
    )
    
    const flowDataIdPostfix = "-sentinel-flow" // 流控规则配置文件后缀
    const groupId = "DEFAULT_GROUP"            // 配置文件所属分组
    const namespace = ""                       // 配置文件所属命名空间
    
    const testFlowRuleUrl = "/flow"
    
    // Nacos服务配置信息
    var sc = []constant.ServerConfig{ 
    	{ 
    		ContextPath: "/nacos",
    		Port:        8848,
    		IpAddr:      "localhost",
    		Scheme:      "http",
    	},
    }
    
    // Nacos客户端配置信息
    var cc = constant.ClientConfig{ 
    	TimeoutMs: 5000,
    }
    
    func main() { 
    	initAll()
    }
    
    func initAll() { 
    	sentinelInit()
    	 创建流控规则：资源名 sayHello 阈值 2 统计间隔 1000毫秒
    	//createFlowRule("testFlowRule", 2, 1000)
    
    	// 初始化Nacos，而非手动创建规则
    	nacosInit()
    	httpInit()
    }
    
    // 初始化http，并注册接口
    func httpInit() { 
    	server := http.Server{ 
    		Addr: "127.0.0.1:8003",
    	}
    	http.HandleFunc(testFlowRuleUrl, testFlowRule)
    	server.ListenAndServe()
    }
    
    // 初始化Sentinel
    func sentinelInit() { 
    	// We should initialize Sentinel first.
    	conf := config.NewDefaultConfig()
    	// for testing, logging output to console
    	conf.Sentinel.Log.Logger = logging.NewConsoleLogger()
    	err := sentinel.InitWithConfig(conf)
    	if err != nil { 
    		log.Fatal(err)
    	}
    }
    
    // 初始化Nacos
    func nacosInit() { 
    	// 生成nacos config client(配置中心客户端)
    	client, err := clients.CreateConfigClient(map[string]interface{ }{ 
    		"serverConfigs": sc,
    		"clientConfig":  cc,
    	})
    	if err != nil { 
    		fmt.Printf("Fail to create client, err: %+v", err)
    		return
    	}
    
    	// 注册流控规则Handler
    	h := datasource.NewFlowRulesHandler(datasource.FlowRuleJsonArrayParser)
    
    	// 创建NacosDataSource数据源
    	// groupId 对应在nacos中创建配置文件的group
    	// dataId 对应在nacos中创建配置文件的dataId，一定要和Nacos配置中心中的配置文件名一致，否则无法匹配
    	dataId := "sentinel-go-sample" + flowDataIdPostfix
    	nds, err := nacos.NewNacosDataSource(client, groupId, dataId, h)
    	if err != nil { 
    		fmt.Printf("Fail to create nacos data source client, err: %+v", err)
    		return
    	}
    
    	//nacos数据源初始化
    	err = nds.Initialize()
    	if err != nil { 
    		fmt.Printf("Fail to initialize nacos data source client, err: %+v", err)
    		return
    	}
    }
    
    // 接口1：测试流控规则
    func testFlowRule(w http.ResponseWriter, r *http.Request) { 
    	resourceName := runFuncName()
    	// 埋点（流控规则方式）
    	e, b := sentinel.Entry(resourceName, sentinel.WithTrafficType(base.Inbound))
    	if b != nil { 
    		fmt.Fprintf(w, "限流！！！")
    	} else { 
    		fmt.Fprintf(w, "测试流控规则~~~")
    		e.Exit()
    	}
    }
    
    // 创建流控规则（默认基于QPS）
    // threshold 阈值
    // interval 统计间隔（毫秒）
    func createFlowRule(resourceName string, threshold float64, interval uint32) { 
    	_, err := flow.LoadRules([]*flow.Rule{ 
    		{ 
    			Resource:               resourceName,
    			TokenCalculateStrategy: flow.Direct,
    			ControlBehavior:        flow.Reject,
    			Threshold:              threshold,
    			StatIntervalInMs:       interval,
    		},
    	})
    	if err != nil { 
    		log.Fatalf("Unexpected error: %+v", err)
    		return
    	}
    }
    
    // 获取正在运行的函数名
    func runFuncName() string { 
    	pc := make([]uintptr, 1)
    	runtime.Callers(2, pc)
    	totalFuncName := runtime.FuncForPC(pc[0]).Name()
    	names := strings.Split(totalFuncName, ".")
    	return names[len(names)-1]
    }

## 1.3 等待idea下载完成依赖库后，启动项目并访问 ##

a. 访问[http://localhost:8003/flow][http_localhost_8003_flow]，查看接口是否正常工作

![image][image 1]

b. 1秒内连续访问，测试一下流控规则是否生效

![image][image 2]

--------------------

### 本文示例源码： ###

[GitHub：WangYe8613/sentinel-go-sample][GitHub_WangYe8613_sentinel-go-sample]

\[commit id：bd8e2ba8a7b3cd92d587c57007f7e509aff2973a\]

[Sentinel-Go_1.Sentinel-Go]: https://blog.csdn.net/w_y_x_y/article/details/115842279
[Nacos_1.Nacos]: https://blog.csdn.net/w_y_x_y/article/details/115558041
[image]: /images/20221022/f24c5006d6084330971fd4ad8f367499.png
[http_localhost_8003_flow]: http://localhost:8003/flow
[image 1]: /images/20221022/5b5dc2fc16d44f4ab8af6a725f00d9f8.png
[image 2]: /images/20221022/fc88f87f82404baa9953f127765b343a.png
[GitHub_WangYe8613_sentinel-go-sample]: https://github.com/WangYe8613/sentinel-go-sample.git