热点key限流
何为热点？
热点即经常访问的数据，很多时候我们希望统计或者限制某个热点数据中访问频次最高的TopN数据，并对其访问进行限流或者其它操作
兜底方法分为系统默认和客户自定义，两种
之前的case，限流出问题后，都是用sentinel系统默认的提示：Blocked by Sentinel (flow limiting)
我们能不能自定?类似hystrix，某个方法出问题了，就找对应的兜底降级方法？
结论：从HystrixCommand 到@SentinelResource
Controller中加入以下代码：
@GetMapping("/testHotKey")
@SentinelResource(value = "testHotKey",blockHandler = "dealHandler_testHotKey")
public String testHotKey(@RequestParam(value = "p1",required = false) String p1,
@RequestParam(value = "p2",required = false) String p2){
return "------testHotKey";
}
public String dealHandler_testHotKey(String p1, String p2, BlockException exception)
{
return "-----dealHandler_testHotKey";
}
使用SentinelResource，则可以替代原本默认显示的Blocked by Sentinel (flow limiting)
限流模式只支持QPS模式，固定写死了。（这才叫热点）
@SentinelResource注解的方法参数索引，0代表第一个参数，1代表第二个参数，以此类推
单机阀值以及统计窗口时长表示在此窗口时间超过阀值就限流。
上面的抓图就是第一个参数有值的话，1秒的QPS为1，超过就限流，限流后调用dealHandler_testHotKey支持方法。
输入：http://localhost:8401/testHotKey?p1=123
和 http://localhost:8401/testHotKey?p1=123&p2=123
一旦一秒超过一次点击，就会降级调用dealHandler_testHotKey
页面显示：-----dealHandler_testHotKey
但输入http://localhost:8401/testHotKey?p2=123
就无影响
有时我们需要当p1有某个特殊值的时候，限流值和平时不一样
假如p1的值为5时设阈值为200
则有：
不断重复输入http://localhost:8401/testHotKey?p1=5
发现不再降级
牢记热点参数的类型必须是基本类型或者String
@SentinelResource
处理的是Sentinel控制台配置的违规情况，有blockHandler方法配置的兜底处理；
RuntimeException
int age = 10/0,这个是java运行时报出的运行时异常RunTimeException，@SentinelResource不管
总结
@SentinelResource主管配置出错，运行出错该走异常走异常
系统规则
配置全局QPS：
按资源名称限流加后续处理
Pom中加入
<dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
<groupId>com.xs.springcloud</groupId>
<artifactId>cloud-api-commons</artifactId>
<version>${project.version}</version>
</dependency>
Controller中加入
@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");
}
}
配置：
关系：
表示1秒内查询次数大于1，则跑到我们自己定义的处理，限流
疯狂刷新网页，则会出现：{"code":444,"message":"com.alibaba.csp.sentinel.slots.block.flow.FlowException\t 服务不可用","data":null}
此时关闭当前模块，则会发现流控规则消失，并没有持久化
按照url地址限流加后续处理
Controller中加入：
@GetMapping("/rateLimit/byUrl")
@SentinelResource(value = "byUrl")
public CommonResult byUrl()
{
return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
}
配置：
疯狂刷新：http://localhost:8401/rateLimit/byUrl
则会出现默认的限流提示
出现的问题：
1 系统默认的，没有体现我们自己的业务要求。
2 依照现有条件，我们自定义的处理方法又和业务代码耦合在一块，不直观。
3 每个业务方法都添加一个兜底的，那代码膨胀加剧。
4 全局统一的处理方法没有体现。
则创建一个CustomerBlockHandler来进行处理
public class CustomerBlockHandler {
public static CommonResult handleException(BlockException exception){
return new CommonResult(2020,"自定义的限流处理信息......CustomerBlockHandler");
}
}
在controller中加入：
/**
* 自定义通用的限流处理逻辑，
blockHandlerClass = CustomerBlockHandler.class
blockHandler = handleException2
上述配置：找CustomerBlockHandler类里的handleException2方法进行兜底处理
*/
/**
* 自定义通用的限流处理逻辑
*/
@GetMapping("/rateLimit/customerBlockHandler")
@SentinelResource(value = "customerBlockHandler",
blockHandlerClass = CustomerBlockHandler.class, blockHandler = "handleException2")
public CommonResult customerBlockHandler()
{
return new CommonResult(200,"按客户自定义限流处理逻辑");
}
疯狂刷新：http://localhost:8401/rateLimit/customerBlockHandler
则出现了：{"code":2020,"message":"自定义的限流处理信息2......CustomerBlockHandler","data":null}
SentinelResource注解属性详解：
服务熔断功能
Sentinel整合了ribbon+openFeign+fallback
创建cloudalibaba-provider-payment9004/9005两个模块
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.xs.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，记得改端口号：
server:
port: 9004
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 PaymentMain9004 {
public static void main(String[] args) {
SpringApplication.run(PaymentMain9004.class, args);
}
}
Controller：
@RestController
public class PaymentController {
@Value("${server.port}")
private String serverPort;
public static HashMap<Long,Payment> hashMap = new HashMap<>();
static
{
hashMap.put(1L,new Payment(1L,"28a8c1e3bc2742d8848569891fb42181"));
hashMap.put(2L,new Payment(2L,"bba8c1e3bc2742d8848569891ac32182"));
hashMap.put(3L,new Payment(3L,"6ua8c1e3bc2742d8848569891xt92183"));
}
@GetMapping(value = "/paymentSQL/{id}")
public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id)
{
Payment payment = hashMap.get(id);
CommonResult<Payment> result = new CommonResult(200,"from mysql,serverPort: "+serverPort,payment);
return result;
}
}
输入：http://localhost:9004/paymentSQL/1
http://localhost:9005/paymentSQL/1
测试正常
接着创建cloudalibaba-consumer-nacos-order84
Pom
<dependencies>
<!--SpringCloud ailibaba nacos -->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!--SpringCloud ailibaba sentinel -->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
<dependency>
<groupId>com.xs.springcloud</groupId>
<artifactId>cloud-api-commons</artifactId>
<version>${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: 84
spring:
application:
name: nacos-order-consumer
cloud:
nacos:
discovery:
server-addr: localhost:8848
sentinel:
transport:
#配置Sentinel dashboard地址
dashboard: localhost:8080
#默认8719端口，假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口
port: 8719
#消费者将要去访问的微服务名称(注册成功进nacos的微服务提供者)
service-url:
nacos-user-service: http://nacos-payment-provider
主启动类：
@EnableDiscoveryClient
@SpringBootApplication
public class OrderNacosMain84 {
public static void main(String[] args) {
SpringApplication.run(OrderNacosMain84.class, args);
}
}
Config：
@Configuration
public class ApplicationContextConfig {
@Bean
@LoadBalanced
public RestTemplate getRestTemplate()
{
return new RestTemplate();
}
}
Controller：
@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;
}
}
访问：http://localhost:84/consumer/fallback/1
会出现错误页面，但这个页面很不好看
接着尝试先只设置fallback
修改controller：
@RequestMapping("/consumer/fallback/{id}")
@SentinelResource(value = "fallback",fallback = "handlerFallback") //fallback负责业务异常
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;
}
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);
}
结果：
http://localhost:84/consumer/fallback/1
{"code":200,"message":"from mysql,serverPort: 9004","data":{"id":1,"serial":"28a8c1e3bc2742d8848569891fb42181"}}
http://localhost:84/consumer/fallback/4
{"code":444,"message":"兜底异常handlerFallback,exception内容 IllegalArgumentException,非法参数异常....","data":{"id":4,"serial":"null"}}
http://localhost:84/consumer/fallback/5
{"code":444,"message":"兜底异常handlerFallback,exception内容 NullPointerException,该ID没有对应记录,空指针异常","data":{"id":5,"serial":"null"}}
注意：这里不需要配置Sentinel
只配置blockHandler
修改Controller
@RequestMapping("/consumer/fallback/{id}")
@SentinelResource(value = "fallback",blockHandler = "blockHandler") //blockHandler负责在sentinel里面配置的降级限流
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 ("非法参数异常....");
}else if (result.getData() == null) {
throw new NullPointerException ("NullPointerException,该ID没有对应记录");
}
return result;
}
public CommonResult handlerFallback(@PathVariable Long id,Throwable e) {
Payment payment = new Payment(id,"null");
return new CommonResult<>(444,"fallback,无此流水,exception "+e.getMessage(),payment);
}
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);
}
编辑降级规则：
疯狂刷新http://localhost:84/consumer/fallback/4
会显示{"code":445,"message":"blockHandler-sentinel限流,无此流水: blockException null","data":{"id":4,"serial":"null"}}
Fallback和blockHandler都配置
修改controller：
@RequestMapping("/consumer/fallback/{id}")
@SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler")
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 ("非法参数异常....");
}else if (result.getData() == null) {
throw new NullPointerException ("NullPointerException,该ID没有对应记录");
}
return result;
}
public CommonResult handlerFallback(@PathVariable Long id,Throwable e) {
Payment payment = new Payment(id,"null");
return new CommonResult<>(444,"fallback,无此流水,exception "+e.getMessage(),payment);
}
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);
}
新增流控规则：
疯狂刷新：http://localhost:84/consumer/fallback/4
显示：{"code":445,"message":"blockHandler-sentinel限流,无此流水: blockException null","data":{"id":4,"serial":"null"}}
可知，若 blockHandler 和 fallback 都进行了配置，则被限流降级而抛出 BlockException 时只会进入 blockHandler 处理逻辑。
忽略属性
修改controller
@RequestMapping("/consumer/fallback/{id}")
@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 ("非法参数异常....");
}else if (result.getData() == null) {
throw new NullPointerException ("NullPointerException,该ID没有对应记录");
}
return result;
}
public CommonResult handlerFallback(@PathVariable Long id,Throwable e) {
Payment payment = new Payment(id,"null");
return new CommonResult<>(444,"fallback,无此流水,exception "+e.getMessage(),payment);
}
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);
}
如果再报IllegalArgumentException，不会再有fallback方法兜底，没有降级效果
因此不需要设置sentinel
输入：http://localhost:84/consumer/fallback/4
显示：There was an unexpected error (type=Internal Server Error, status=500).
非法参数异常....
java.lang.IllegalArgumentException: 非法参数异常....
Feign模块
Feign组件一般用于消费侧
对84模块进行修改
Pom中加入：
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
Yml中加入：
management:
endpoints:
web:
exposure:
include: '*'
# 激活Sentinel对Feign的支持
feign:
sentinel:
enabled: true
service模块：
//使用 fallback 方式是无法获取异常信息的，
//如果想要获取异常信息，可以使用 fallbackFactory参数
@FeignClient(value = "nacos-payment-provider",fallback = PaymentFallBackService.class)//调用中关闭9003服务提供者
public interface PaymentService {
@GetMapping(value = "/paymentSQL/{id}")
public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id);
}
@Component
public class PaymentFallBackService implements PaymentService{
@Override
public CommonResult<Payment> paymentSQL(Long id) {
return new CommonResult<>(444,"服务降级返回,没有该流水信息",new Payment(id, "errorSerial......"));
}
}
Controller中加入：
//==================OpenFeign
@Resource
private PaymentService paymentService;
@GetMapping(value = "/consumer/openfeign/{id}")
public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id)
{
if(id == 4)
{
throw new RuntimeException("没有该id");
}
return paymentService.paymentSQL(id);
}
主启动类加入注解：@EnableFeignClients
网址输入：http://localhost:84/consumer/openfeign/1
一切正常，关闭9004和9005，可以看到降级成功：
{"code":444,"message":"服务降级返回,没有该流水信息","data":{"id":1,"serial":"errorSerial......"}}
熔断框架对比：
规则持久化
每次重启，可以看到sentinel里的规则消失，而生产环境需要将配置规则持久化
将限流规则持久化进Nacos，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里的配置不删除，针对8401上的sentinel上的流控规则持续有效
修改8401
Pom中记得加：
<!--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>
Yml：
在sentinel下
datasource:
ds1:
nacos:
server-addr: localhost:8848
dataId: cloudalibaba-sentinel-service
groupId: DEFAULT_GROUP
data-type: json
rule-type: flow
新建配置：
resource：资源名称；
limitApp：来源应用；
grade：阈值类型，0表示线程数，1表示QPS；
count：单机阈值；
strategy：流控模式，0表示直接，1表示关联，2表示链路；
controlBehavior：流控效果，0表示快速失败，1表示Warm Up，2表示排队等待；
clusterMode：是否集群。
发布完重启8401，就能看到sentinel里有这个规则了：
访问http://localhost:8401/rateLimit/byUrl
发现规则确实启用了
停止8401模块发现规则就消失了，重启后发现又出现，证明持久化有效
以上为124到137集的内容
