文章目录
SpringCloud Alibaba Sentinel实现熔断与限流
1、Sentinel
- 为什么
一句话解释，之间我们讲解过的Hystrix
- 能干嘛
-
怎么玩：解决那些问题
服务血崩
服务降级
服务熔断
服务限流
2、安装Sentinel控制台
- sentinel组件有两部分构成：前台和后台8080
-
下载jar包并启动
-
访问页面
3、初始化演示工程
-
启动8848成功
-
建Module
1、cloudalibaba-sentinel-service8401
2、POM
<dependencies> <dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity --> <groupId>com.atguigu.springcloud</groupId> <artifactId>cloud-api-common</artifactId> <version>${project.version}</version> </dependency> <!--SpringCloud ailibaba nacos --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <!--SpringCloud ailibaba sentinel-datasource-nacos 后续做持久化用到--> <dependency> <groupId>com.alibaba.csp</groupId> <artifactId>sentinel-datasource-nacos</artifactId> </dependency> <!--SpringCloud ailibaba sentinel --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId> </dependency> <!--openfeign--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> <!-- SpringBoot整合Web组件+actuator --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <!--日常通用jar包配置--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> <optional>true</optional> </dependency> <dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-all</artifactId> <version>4.6.3</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies>3、yml
server: port: 8401 spring: application: name: cloudalibaba-sentinel-service cloud: nacos: discovery: server-addr: 192.168.149.102:1111 #Nacos服务注册中心地址 sentinel: transport: dashboard: localhost:8080 #配置Sentinel dashboard地址 port: 8719 management: endpoints: web: exposure: include: '*'4、主启动类
@EnableDiscoveryClient @SpringBootApplication public class MainApp8401 { public static void main(String[] args) { SpringApplication.run(MainApp8401.class, args); } }5、业务类FlowLimitController类
@Slf4j public class FlowLimitController { @GetMapping("/testA") public String testA() { return "------testA"; } @GetMapping("/testB") public String testB() { log.info(Thread.currentThread().getName()+"\t"+"...testB"); return "------testB"; } } -
启动sentinel8080
-
启动微服务8401
-
启动8401微服务后查看sentinel控制台
1、sentinel采用的是懒加载说明
http://localhost:8401/testA
http://localhost:8401/testB
2、效果
4、流控规则
-
基本介绍
-
流控模式
1、默认直接
直接–>快速失败
配置说明
测试
1秒钟点击1下，OK
点击超过每秒的访问量，进行流量控制
2、关联
-
是什么？
当关联的资源达到阈值时，就限流自己
当与A关联的资源B达到阈值后，就限流自己
B惹事，A挂了
-
配置A
-
postman模拟并发密集访问testB
访问testB成功
postman里新建多线程集合组
-
测试
大批量线程高并发访问B，导致A失效了
A挂了
-
流控效果
1、直接->快速失败（默认的流控处理）
直接失败，抛出异常 --> Blocked by Sentinel (flow limiting)
源码 --> com.alibaba.csp.sentinel.slots.block.flow.controller.DefaultController
2、预热
-
说明
公式：阈值除以coldFactor（默认值为3），经过预热时长后才会达到阈值
-
限流 冷启动
-
默认coldFactor为3，即请求QPS从threshold/3开始，经预热时长逐渐升至设定的QPS阈值。
-
源码
com.alibaba.csp.sentinel.slots.block.flow.controller.WarmUpController
-
Warmup配置
-
测试
多次点击http://localhost:8401/testB
刚开始不行，后续慢慢OK
-
应用场景
-
排队等待
1、匀速排队，阈值必须设置为QPS
2、官网
3、源码
com.alibaba.csp.sentinel.slots.block.flow.controller.RateLimiterController
4、测试
5、降级规则
- 基本介绍
进一步说明
Sentinel的断路器是没有半开状态的
半开的状态系统自动去检测是否请求有异常，没有异常就关闭断路器恢复使用，有异常则继续打开断路器不可用。具体可以参考Hystrix
-
降级策略实战
1、RT
- 是什么
-
测试
1、代码
@GetMapping("/testD") public String testD() { try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { e.printStackTrace(); } log.info("testD 测试RT"); return "------testD"; }2、配置
2毫秒内处理请求，否则断电，时间窗口1秒后恢复
3、jmeter
http://localhost:8401/testD
**启动**
关闭
2、异常比例
是什么
代码
@GetMapping("/testD")
public String testD()
{
log.info("testD 测试RT");
int age = 10/0;
return "------testD";
}
配置
jmeter
并发访问http://localhost:8401/testD大于5个
结论
3、异常数
是什么
异常数是按照分钟统计的
测试
-
代码
@GetMapping("/testE") public String testE() { log.info("testE 测试异常数"); int age = 10/0; return "------testE 测试异常数"; } -
配置
6、热点key限流
1、基本介绍
官网
@SentinelResource
代码
com.alibaba.csp.sentinel.slots.block.BlockException
@GetMapping("/testHotKey")
@SentinelResource(value = "testHotKey",blockHandler = "deal_testHotKey")
public String testHotKey(@RequestParam(value = "p1",required = false) String p1,
@RequestParam(value = "p2",required = false) String p2) {
//int age = 10/0;
return "------testHotKey";
}
//兜底方法
public String deal_testHotKey (String p1, String p2, BlockException exception){
return "------deal_testHotKey,o(╥﹏╥)o";
}
@SentinelResource(value = “testHotKey”)
异常打到了前台用户界面看不到，不友好
@SentinelResource(value = “testHotKey”,blockHandler = “deal_testHotKey”)@SentinelResource(value = “testHotKey”,blockHandler = “deal_testHotKey”)
方法testHostKey里面第一个参数只要QPS超过每秒1次，马上降级处理 用了我们自己定义的
配置
测试
http://localhost:8401/testHotKey?p1=abc error
http://localhost:8401/testHotKey?p1=abc&p2=33 error
http://localhost:8401/testHotKey?p2=abc right
结论
上述案例演示了第一个参数p1,当QPS超过1秒1次点击后马上被限流
2、参数例外项
-
特殊情况
超过1秒钟一个后，达到阈值1后马上被限流
我们期望p1参数当它是某个特殊值时，它的限流值和平时不一样
假如当p1的值等于5时，它的阈值可以达到200
-
配置
添加按钮不能忘
-
测试
http://localhost:8401/testHotKey?p1=5 通过
http://localhost:8401/testHotKey?p1=3 失败
当p1等于5的时候，阈值变为200
当p1不等于5的时候，阈值就是平常的1
-
前提条件
热点参数的注意点，参数必须是基本类型或者String
-
其他
7、系统规则
-
是什么
-
各项配置参数说明
-
配置全局QPS
8、@SentinelResource
1、按资源名称限流+后续处理
-
修改cloudalibaba-sentinel-service8401
-
POM
<dependency> <groupId>com.atguigu.springcloud</groupId> <artifactId>cloud-api-common</artifactId> <version>${project.version}</version> </dependency> -
yml
server: port: 8401 spring: application: name: cloudalibaba-sentinel-service cloud: nacos: discovery: server-addr: localhost:8848 sentinel: transport: dashboard: localhost:8080 port: 8719 #默认8719，假如被占用了会自动从8719开始依次+1扫描。直至找到未被占用的端口 management: endpoints: web: exposure: include: '*' -
业务类RateLimitController
@RestController public class RateLimitController { @GetMapping("/byResource") @SentinelResource(value = "byResource",blockHandler = "handleException") public CommonResult byResource() { return new CommonResult(200,"按资源名称限流测试OK",new Payment(2020L,"serial001")); } public CommonResult handleException(BlockException exception) { return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用"); } -
主启动
@EnableDiscoveryClient @SpringBootApplication public class MainApp8401 { public static void main(String[] args) { SpringApplication.run(MainApp8401.class, args); } } -
配置流控规则
配置步骤
表示1秒钟内查询次数大于1，就跑到我们自定义的处流，限流
-
测试
1秒钟点击1下，OK
超过上述问题，疯狂点击，返回了自己定义的限流处理信息，限流发送
- 额外问题
此时关闭微服务8401看看
Sentinel控制台，流控规则消失了？？？？？ 临时的
2、按照Url地址限流+后续处理
通过访问的URL来限流，会返回Sentinel自带默认的限流处理信息
业务类RateLimitController
@GetMapping("/rateLimit/byUrl")
@SentinelResource(value = "byUrl")
public CommonResult byUrl()
{
return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
}
控制台配置
测试：
疯狂点击http://localhost:8401/rateLimit/byUrl
上面兜底方法存在的问题
3、客户自定义限流处理逻辑
-
创建customerBlockHandler类用于自定义限流处理逻辑
-
自定义限流处理类
package com.atguigu.springcloud.alibaba.myhandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.springcloud.entities.*;
public class CustomerBlockHandler {
public static CommonResult handleException(BlockException exception) {
return new CommonResult(2020, "自定义限流处理信息....CustomerBlockHandler");
}
}
-
RateLimitController
@GetMapping("/rateLimit/customerBlockHandler") @SentinelResource(value = "customerBlockHandler", blockHandlerClass = CustomerBlockHandler.class, blockHandler = "handlerException2") public CommonResult customerBlockHandler() { return new CommonResult(200,"按客戶自定义",new Payment(2020L,"serial003")); } -
启动微服务后先调用一次
http://localhost:8401/rateLimit/customerBlockHandler
-
Sentinel控制台配置
- 测试
- 进一步说明
4、更多注解属性说明
- 代码配置
- 注解
-
Sentinel主要有三个核心API
SphU定义资源
Tracer定义统计
ContextUtil定义了上下文
9、服务熔断功能
sentinel整合ribbon+openFeign+fallback
Ribbon系列
1、提供者9003/9004
-
新建cloudalibaba-provider-payment9003/9004
-
POM
<dependencies> <!--SpringCloud ailibaba nacos --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity --> <groupId>com.atguigu.springcloud</groupId> <artifactId>cloud-api-commons</artifactId> <version>${project.version}</version> </dependency> <!-- SpringBoot整合Web组件 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <!--日常通用jar包配置--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> <optional>true</optional> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> -
yml
server: port: 9003 spring: application: name: nacos-payment-provider cloud: nacos: discovery: server-addr: localhost:8848 #配置Nacos地址 management: endpoints: web: exposure: include: '*' -
主启动类
@SpringBootApplication @EnableDiscoveryClient public class PaymentMain9003 { public static void main(String[] args) { SpringApplication.run(PaymentMain9003.class, args); } } -
业务类
public class PaymentController { @Value("${server.port}") private String serverPort; public static HashMap<Long, Payment> hashMap = new HashMap<>(); static{ hashMap.put(1L,new Payment(1L,"28a8c1e3bc2742d8848569891fb42181")); hashMap.put(2L,new Payment(2L,"bba8c1e3bc2742d8848569891ac32182")); hashMap.put(3L,new Payment(3L,"6ua8c1e3bc2742d8848569891xt92183")); } @GetMapping(value = "/paymentSQL/{id}") public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id){ Payment payment = hashMap.get(id); CommonResult<Payment> result = new CommonResult(200,"from mysql,serverPort: "+serverPort,payment); return result; } } -
测试地址
http://localhost:9003/paymentSQL/1
2、消费者84
-
新建cloudalibaba-consumer-nacos-order84
-
POM
<dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId> </dependency> <dependency> <groupId>com.atguigu.springcloud</groupId> <artifactId>cloud-api-commons</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> <optional>true</optional> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> -
yml
server: port: 84 spring: application: name: nacos-order-consumer cloud: nacos: discovery: server-addr: localhost:8848 sentinel: transport: dashboard: localhost:8080 port: 8719 service-url: nacos-user-service: http://nacos-payment-provider -
主启动
@EnableDiscoveryClient @SpringBootApplication @EnableFeignClients public class OrderNacosMain84 { public static void main(String[] args) { SpringApplication.run(OrderNacosMain84.class, args); } } -
业务类
ApplicationContextConfig
@Configuration public class ApplicationContextConfig { @Bean @LoadBalanced public RestTemplate getRestTemplate() { return new RestTemplate(); } }CircleBreakerController
package com.atguigu.springcloud.alibaba.controller; import com.alibaba.csp.sentinel.annotation.SentinelResource; import com.alibaba.csp.sentinel.slots.block.BlockException; import com.atguigu.springcloud.alibaba.entities.CommonResult; import com.atguigu.springcloud.alibaba.entities.Payment; import lombok.extern.slf4j.Slf4j; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.client.RestTemplate; import javax.annotation.Resource; @RestController @Slf4j public class CircleBreakerController { public static final String SERVICE_URL = "http://nacos-payment-provider"; @Resource private RestTemplate restTemplate; @RequestMapping("/consumer/fallback/{id}") //@SentinelResource(value = "fallback") //没有配置 //@SentinelResource(value = "fallback",fallback = "handlerFallback") //fallback只负责业务异常 //@SentinelResource(value = "fallback",blockHandler = "blockHandler") //blockHandler只负责sentinel控制台配置违规 @SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler", exceptionsToIgnore = {IllegalArgumentException.class}) public CommonResult<Payment> fallback(@PathVariable Long id) { CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id, CommonResult.class,id); if (id == 4) { throw new IllegalArgumentException ("IllegalArgumentException,非法参数异常...."); }else if (result.getData() == null) { throw new NullPointerException ("NullPointerException,该ID没有对应记录,空指针异常"); } return result; } //fallback public CommonResult handlerFallback(@PathVariable Long id,Throwable e) { Payment payment = new Payment(id,"null"); return new CommonResult<>(444,"兜底异常handlerFallback,exception内容 "+e.getMessage(),payment); } //blockHandler public CommonResult blockHandler(@PathVariable Long id,BlockException blockException) { Payment payment = new Payment(id,"null"); return new CommonResult<>(445,"blockHandler-sentinel限流,无此流水: blockException "+blockException.getMessage(),payment); } }没有任何配置
@RestController @Slf4j public class CircleBreakerController { public static final String SERVICE_URL = "http://nacos-payment-provider"; @Resource private RestTemplate restTemplate; @RequestMapping("/consumer/fallback/{id}") @SentinelResource(value = "fallback") public CommonResult<Payment> fallback(@PathVariable Long id) { CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id); if (id == 4) { throw new IllegalArgumentException ("IllegalArgumentException,非法参数异常...."); }else if (result.getData() == null) { throw new NullPointerException ("NullPointerException,该ID没有对应记录,空指针异常"); } return result; }
忽略属性
编码（那个业务类下面的CircleBreakerController的全部源码）
-
Feign系列
1、修改84模块
-
pom
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> -
yml
server: port: 84 spring: application: name: nacos-order-consumer cloud: nacos: discovery: server-addr: localhost:8848 sentinel: transport: dashboard: localhost:8080 port: 8719 service-url: nacos-user-service: http://nacos-payment-provider #对Feign的支持 feign: sentinel: enabled: true2、业务类
-
带@FeignClient注解的业务接口
@FeignClient(value = "nacos-payment-provider",fallback = PaymentFallbackService.class) public interface PaymentService { @GetMapping(value = "/paymentSQL/{id}") public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id); } -
fallback = PaymentFallbackService.class
-
PaymentFallbackService实现类
Component public class PaymentFallbackService implements PaymentService { @Override public CommonResult<Payment> paymentSQL(Long id) { return new CommonResult<>(44444,"服务降级返回,---PaymentFallbackService",new Payment(id,"errorSerial")); } } -
Controller
// OpenFeign @Resource private PaymentService paymentService; @GetMapping(value = "/consumer/paymentSQL/{id}") public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id) { return paymentService.paymentSQL(id); } -
主启动
添加@EnableFeignClients启动Feign的功能
@EnableDiscoveryClient @SpringBootApplication @EnableFeignClients public class OrderNacosMain84 { public static void main(String[] args) { SpringApplication.run(OrderNacosMain84.class, args); } } -
测试
http://lcoalhost:84/consumer/paymentSQL/1
测试84调用9003，此时故意关闭9003微服务提供者，看84消费侧自动降级，不会被耗死
熔断框架比较
10、规则持久化
-
是什么
一旦我们重启应用，Sentinel规则将消失，生产环境需要将配置规则进行持久化
-
怎么玩
将限流配置规则持久化进Nacos保存，只要刷新8401某个rest地址，sentinel控制台的流控规则就能看到，只要Nacos里面的配置不删除，针对8401上Sentinel上的流控规则持续有效
-
步骤
1、修改cloudalibaba-sentinel-service8401
2、pom
<dependency> <groupId>com.alibaba.csp</groupId> <artifactId>sentinel-datasource-nacos</artifactId> </dependency>3、yml
server: port: 8401 spring: application: name: cloudalibaba-sentinel-service cloud: nacos: discovery: server-addr: localhost:8848 #Nacos服务注册中心地址 sentinel: transport: dashboard: localhost:8080 #配置Sentinel dashboard地址 port: 8719 datasource: ds1: nacos: server-addr: localhost:8848 dataId: cloudalibaba-sentinel-service groupId: DEFAULT_GROUP data-type: json rule-type: flow management: endpoints: web: exposure: include: '*' feign: sentinel: enabled: true # 激活Sentinel对Feign的支持添加了数据源
spring: cloud: sentinel: datasource: ds1: nacos: server-addr:localhost:8848 dataid:${spring.application.name} groupid:DEFAULT_GROUP data-type:json rule-type:flow4、添加Nacos业务规则配置
内容解析[ { "resource": "/retaLimit/byUrl", "limitApp": "default", "grade": 1, "count": 1, "strategy": 0, "controlBehavior": 0, "clusterMode": false } ]
5、测试
启动8401后刷新sentinel发现业务规则有了
-
快速访问测试接口
http://localhost:8401/rateLimit/byUrl
-
停止8401再看sentinel
配置规则消失
-
重新启动8401再看sentinel
多次调用 http://localhost:8401/rateLimit/byUrl
重新配置出现了，持久化验证通过
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