很多新手不知道如何在阿里巴巴设置开源哨兵限流方案。为了帮助大家解决这个问题，下面小编就为大家详细讲解一下。需要的人可以从中学习，希望你能有所收获。
Sentinel是阿里开源的限流方案框架，具有以下特点：
丰富的应用场景:哨兵承担了阿里巴巴双十一近10年流量提升的核心场景，如尖峰(即突发流量控制在系统容量范围内)、消息削峰填谷、集群流量控制、下游不可用应用实时融合等。
完备的实时监控:哨兵还提供实时监控功能。可以在控制台看到单机访问应用的二级数据，甚至500台以下集群的汇总操作。
广泛的开源生态:哨兵提供了与其他开源框架/库的现成集成模块，例如与Spring Cloud、Dubbo和gRPC的集成。您只需引入相应的依赖项并简单地配置它们，就可以快速访问Sentinel。
完善的 SPI 扩展点:哨兵提供简单完善的SPI扩展接口。您可以通过实现扩展接口来快速定制逻辑。例如，定制规则管理、适配动态数据源等。
第一，搭建监控平台。
1.下载相应的jar包，地址在https://github.com/alibaba/Sentinel/releases.
2.start Java-dserver . port=8080-dcsp . sentinel . dashboard . server=localhost :8080-dpproject . name=sentinel-dashboard-jar-dsen tiel . dashboard . auth . usernam . e=sentinel-dsen tiel . dashboard . auth . password=123456 sentinel-dashboard-1 . 6 . 3 . jar
-dsen tiel . dashboard . auth . username指定登录名。
-dsen tiel . dashboard . auth . password指定登录密码。
3.访问localhost:8080并输入用户密码。
4.看到以下效果，构建成功。
第二，客户端使用。
以注释的使用为例。
1.maven依赖。
？xmlversion='1.0 '编码='UTF-8 '？
project xmlns=' http://aven . Apache . org/POM/4 . 0 . 0 '
xmlns : xsi=' http://www . w3 . org/2001/XMLSchema-instance '
xsi : schema location=' http://aven . Apache . org/POM/4 . 0 . 0http://aven . Apache . org/xsd/maven-4 . 0 . 0 . xsd '
模型版本4 . 0 . 0/模型版本
artifactIdsentinel-演示-注释-spring-aop/artifactId
父母
groupIdorg.springframework.boot/groupId
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.6.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-core</artifactId>
<version>1.6.3</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-transport-simple-http</artifactId>
<version>1.6.3</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-annotation-aspectj</artifactId>
<version>1.6.3</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
</project>
2.配置限流规则方案
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.csp.sentinel.demo.annotation.aop.config;
import com.alibaba.csp.sentinel.annotation.aspectj.SentinelResourceAspect;
import com.alibaba.csp.sentinel.slots.block.RuleConstant;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
import java.util.ArrayList;
import java.util.List;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* @author Eric Zhao
*/
@Configuration
public class AopConfiguration {
@Bean
public SentinelResourceAspect sentinelResourceAspect() {
//配置固定限流规则，每秒为20qps,真对test
List<FlowRule> rules = new ArrayList<>();
FlowRule rule = new FlowRule();
rule.setResource("test");
rule.setGrade(RuleConstant.FLOW_GRADE_QPS);
// Set limit QPS to 20.
rule.setCount(20);
rules.add(rule);
FlowRuleManager.loadRules(rules);
return new SentinelResourceAspect();
}
}
3.实际应用
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.csp.sentinel.demo.annotation.aop.service;
import org.springframework.stereotype.Service;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
/**
* @author Eric Zhao
*/
@Service
public class TestServiceImpl implements TestService {
@Override
@SentinelResource(value = "test", blockHandler = "handleException", blockHandlerClass = {ExceptionUtil.class})
public void test() {
System.out.println("Test");
}
@Override
@SentinelResource(value = "hello", fallback = "helloFallback")
public String hello(long s) {
if (s < 0) {
throw new IllegalArgumentException("invalid arg");
}
return String.format("Hello at %d", s);
}
@Override
@SentinelResource(value = "helloAnother", defaultFallback = "defaultFallback",
exceptionsToIgnore = {IllegalStateException.class})
public String helloAnother(String name) {
if (name == null || "bad".equals(name)) {
throw new IllegalArgumentException("oops");
}
if ("foo".equals(name)) {
throw new IllegalStateException("oops");
}
return "Hello, " + name;
}
public String helloFallback(long s, Throwable ex) {
// Do some log here.
ex.printStackTrace();
return "Oops, error occurred at " + s;
}
public String defaultFallback() {
System.out.println("Go to default fallback");
return "default_fallback";
}
}
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.csp.sentinel.demo.annotation.aop.controller;
import com.alibaba.csp.sentinel.demo.annotation.aop.service.TestService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
/**
* @author Eric Zhao
*/
@RestController
public class DemoController {
@Autowired
private TestService service;
@GetMapping("/foo")
public String apiFoo(@RequestParam(required = false) Long t) throws Exception {
if (t == null) {
t = System.currentTimeMillis();
}
service.test();
return service.hello(t);
}
@GetMapping("/baz/{name}")
public String apiBaz(@PathVariable("name") String name) {
return service.helloAnother(name);
}
}
4.启动应用，-Dproject.name=test -Dcsp.sentinel.dashboard.server=localhost:8080 访问接口就可以看到监控信息了
-Dproject.name=test 指定监控名称
-Dcsp.sentinel.dashboard.server 指定监控平台地址
三、简单基于注解原理分析
1.sentinel 主要的核心功能由sentinel-core 提供，基于注解的应用主要是依赖于切面的使用，具体的实现如下
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.csp.sentinel.annotation.aspectj;
import com.alibaba.csp.sentinel.Entry;
import com.alibaba.csp.sentinel.EntryType;
import com.alibaba.csp.sentinel.SphU;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import java.lang.reflect.Method;
/**
* Aspect for methods with {@link SentinelResource} annotation.
*
* @author Eric Zhao
*/
@Aspect
public class SentinelResourceAspect extends AbstractSentinelAspectSupport {
@Pointcut("@annotation(com.alibaba.csp.sentinel.annotation.SentinelResource)")
public void sentinelResourceAnnotationPointcut() {
}
@Around("sentinelResourceAnnotationPointcut()")
public Object invokeResourceWithSentinel(ProceedingJoinPoint pjp) throws Throwable {
Method originMethod = resolveMethod(pjp);
SentinelResource annotation = originMethod.getAnnotation(SentinelResource.class);
if (annotation == null) {
// Should not go through here.
throw new IllegalStateException("Wrong state for SentinelResource annotation");
}
String resourceName = getResourceName(annotation.value(), originMethod);
EntryType entryType = annotation.entryType();
int resourceType = annotation.resourceType();
Entry entry = null;
try {
entry = SphU.entry(resourceName, resourceType, entryType, pjp.getArgs());
Object result = pjp.proceed();
return result;
} catch (BlockException ex) {
return handleBlockException(pjp, annotation, ex);
} catch (Throwable ex) {
Class<? extends Throwable>[] exceptionsToIgnore = annotation.exceptionsToIgnore();
// The ignore list will be checked first.
if (exceptionsToIgnore.length > 0 && exceptionBelongsTo(ex, exceptionsToIgnore)) {
throw ex;
}
if (exceptionBelongsTo(ex, annotation.exceptionsToTrace())) {
traceException(ex, annotation);
return handleFallback(pjp, annotation, ex);
}
// No fallback function can handle the exception, so throw it out.
throw ex;
} finally {
if (entry != null) {
entry.exit(1, pjp.getArgs());
}
}
}
}
与单机的应用其实是一样的，初始化规则，调用SphU的entry方法，判断限流机制
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