分布式系统中，对于熔断和流控的需求是很基础的，在开源市场中我们选择并不是很多，SpringCloud 全家桶中有hystrix，不过由于hystrix已经停更了那么显然不是一个好的选择，那么比较出名的可能只有阿里开源的Sentinel可以使用了
Sentinel开源版还是阉割了很多功能的，并且二次开发比较繁琐，如果公司有这个预算的话还是建议直接去aliyun购买付费Sentinel服务，一键式傻瓜接入
Sentinel介绍：
资源
资源是 Sentinel 的关键概念。它可以是 Java 应用程序中的任何内容，例如，由应用程序提供的服务，或由应用程序调用的其它应用提供的服务，甚至可以是一段代码。在接下来的文档中，我们都会用资源来描述代码块。
只要通过 Sentinel API 定义的代码，就是资源，能够被 Sentinel 保护起来。大部分情况下，可以使用方法签名，URL，甚至服务名称作为资源名来标示资源。
规则
围绕资源的实时状态设定的规则，可以包括流量控制规则、熔断降级规则以及系统保护规则。所有规则可以动态实时调整。
Springboot2 接入 Sentinel：（上面的配置包含了gateway网关，以及普通应用接入需要的pom引入）
<alibaba.sentinel.version>1.8.0</alibaba.sentinel.version>
<alibaba.sentinel.cloud.version>2.1.2.RELEASE</alibaba.sentinel.cloud.version>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-api-gateway-adapter-common</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-dubbo-adapter</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-alibaba-sentinel-gateway</artifactId>
<version>${alibaba.sentinel.cloud.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
<version>${alibaba.sentinel.cloud.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-core</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-annotation-aspectj</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-web-servlet</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-parameter-flow-control</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>
<dependency>
<groupId>com.alibaba.csp</groupId>
<artifactId>sentinel-transport-simple-http</artifactId>
<version>${alibaba.sentinel.version}</version>
</dependency>如果需要改变Sentinel的日志记录路径，那么必须在发布的启动脚本中加上参数指名：-Dcsp.sentinel.log.dir=XXX
通过上面步骤，基本上客户端已经完成了接入Sentinel服务端的步骤，相对来说还是比较简单的，但是这些都只是基本接入，数据源的持久化以及多节点心跳检测的问题都还未优化
下面说下Sentinel管理后台的接入步骤：
1.去github上面下载sentinel源码
这部分代码copy出来稍加配置改动就可以了
Docker容器客户端多节点部署，源代码心跳检测会出现机器数量缺失部分节点，解决方案：
客户端启动时使用一个定时异步线程池，每15秒执行一次心跳检测线程就可以了
public class SentinelMachineRunnable implements Runnable {
private static final String APPNAME = System.getenv("APPNAME");
private static final String ENV = System.getenv("envID");
private static final String PODIP = System.getenv("POD_IP");
private String sentinel_address;
private static String hostName = "";
protected static final Logger log = LoggerFactory.getLogger( SentinelMachineRunnable.class );
public SentinelMachineRunnable(String sentinel_address) {
this.sentinel_address = sentinel_address;
}
@Override
public void run() {
//网关的心跳检测发送有点特殊，type值不一样，所以需要排除gateway应用做兼容
if (!Constants.ENV.equalsIgnoreCase( "local" ) && !Constants.APPNAME.contains( "gateway" )) {
if ("".equals( hostName )) {
InetAddress addr = null;
try {
addr = InetAddress.getLocalHost();
} catch (UnknownHostException e) {
log.error( "SentinelMachineRunnable is error", e );
}
hostName = addr.getHostName();
}
Map<String, Object> param = new HashMap<>();
param.put( "appType", 0 );
param.put( "hostname", hostName );
param.put( "ip", Constants.PODIP );
param.put( "port", 8719 );
param.put( "version", System.currentTimeMillis() );
param.put( "v", "1.7.2" );
Result<?> sentinelResult = null;
try {
String result = HttpClientUtil.doPost( "http://" + sentinel_address + "/registry/machine", param );
sentinelResult = JSON.parseObject( result, Result.class );
if (Optional.ofNullable( sentinelResult ).isPresent()) {
if (!sentinelResult.isSuccess()) {
log.warn( "SentinelMachineRunnable is error,result is {},sentinel_address is {},param is {},appname is {},ip is {},env is {}",
sentinelResult, sentinel_address, param, Constants.APPNAME, Constants.PODIP, Constants.ENV );
}
}
} catch (Exception e) {
log.warn( "SentinelMachineRunnable is error,result is {},sentinel_address is {},param is {},appname is {},ip is {},env is {},exception is {}",
sentinelResult, sentinel_address, param, Constants.APPNAME, Constants.PODIP, Constants.ENV, e.getMessage() );
}
}
}
}
数据源持久化解决方案：
1.官方建议持久化方案是Nacos做配置中心，但是我们才用了Apollo，如果所有配置都想持久化对Sentinel的后台二开工作量还是比较大的，原生持久化设计流程如下图
这种方式二开改造比较麻烦，还需要处理apoolo的token，部分公司可能堆token的签发还会有很多权限拦截比较麻烦
2.鉴于上面一种方式在我们公司比较难弄，我们持久化改造成下面流程了
核心代码如下：
@Configuration
public class SentinelConfigHotChange implements EnvironmentAware {
private static final String DEFAULT = "default";
private static final String SENTINEL_SIT_NAMESPACE = "仓储物流组.sit";
private static final String SENTINEL_UAT_NAMESPACE = "仓储物流组.uat";
private static final String SENTINEL_PROD_NAMESPACE = "仓储物流组.prod";
private static final String RT_EXCEPTION = "spring.cloud.sentinel.re.config";
private static final String GATEWAY_CONFIG = "spring.cloud.sentinel.gateway.config";
private static final Map<String, Config> APOLLO_SENTINEL_CONFIG_NAMESPACE = new HashMap<>();
@Value("${spring.profiles.active:local}")
private String profile;
private Binder binder;
private Environment evn; //获取配置文件的配置信息
@ApolloConfig
private Config applicationConfig;
protected static final Logger log = LoggerFactory.getLogger( SentinelConfigHotChange.class );
/**
* <p>Title:根据profile判断apollo需要监听的namespace</p>
* <p>Description:动态判断监听对象</p>
*
* @return java.lang.String
* @throws
* @author QIQI
* @params []
* @date 2019-12-11 12:33
*/
public void initApolloListenerConfig() {
if (APOLLO_SENTINEL_CONFIG_NAMESPACE.isEmpty()) {
APOLLO_SENTINEL_CONFIG_NAMESPACE.put( DEFAULT, applicationConfig );
if (profile.equalsIgnoreCase( "local" )) {
APOLLO_SENTINEL_CONFIG_NAMESPACE.put( profile, ConfigService.getConfig( SENTINEL_SIT_NAMESPACE ) );
} else if (profile.equalsIgnoreCase( "sit" )) {
APOLLO_SENTINEL_CONFIG_NAMESPACE.put( profile, ConfigService.getConfig( SENTINEL_SIT_NAMESPACE ) );
} else if (profile.equalsIgnoreCase( "uat" )) {
APOLLO_SENTINEL_CONFIG_NAMESPACE.put( profile, ConfigService.getConfig( SENTINEL_UAT_NAMESPACE ) );
} else if (profile.equalsIgnoreCase( "prod" )) {
APOLLO_SENTINEL_CONFIG_NAMESPACE.put( profile, ConfigService.getConfig( SENTINEL_PROD_NAMESPACE ) );
} else {
APOLLO_SENTINEL_CONFIG_NAMESPACE.put( profile, ConfigService.getConfig( SENTINEL_SIT_NAMESPACE ) );
}
}
}
/**
* <p>Title:采用手动注册方式监听配置</p>
* <p>Description:因为需要动态监听，不能使用注解形式</p>
*
* @return void
* @throws
* @author QIQI
* @params []
* @date 2019-12-11 13:20
*/
private void addApolloConfigChangeListener() {
applicationConfig.addChangeListener( (configChangeEvent) -> {
if (configChangeEvent.isChanged( RT_EXCEPTION ) || configChangeEvent.isChanged( GATEWAY_CONFIG )) {
try {
flushSentinelConfig();
} catch (Exception e) {
log.warn( "addApolloConfigChangeListener is error", e );
}
}
} );
APOLLO_SENTINEL_CONFIG_NAMESPACE.get( profile ).addChangeListener( (configChangeEvent) -> {
try {
if (configChangeEvent.isChanged( RT_EXCEPTION ) || configChangeEvent.isChanged( GATEWAY_CONFIG ))
flushSentinelConfig();
log.info( "addApolloConfigChangeListener SENTINEL_ADD_LISTENER ------->" );
} catch (Exception throwables) {
log.warn( "addApolloConfigChangeListener is error", throwables );
}
} );
}
/**
* <p>Title:热刷新数据源，重置shardingjdbc</p>
* <p>Description:</p>
*
* @return void
* @throws
* @author QIQI
* @params []
* @date 2020/05/27 19:54
*/
private void flushSentinelConfig() throws Exception {
log.info( "addApolloConfigChangeListener flushSentinelConfig ------->" );
Config config;
if (APOLLO_SENTINEL_CONFIG_NAMESPACE.get( DEFAULT ).getPropertyNames().contains( RT_EXCEPTION ) ||
APOLLO_SENTINEL_CONFIG_NAMESPACE.get( DEFAULT ).getPropertyNames().contains( GATEWAY_CONFIG )) {
config = APOLLO_SENTINEL_CONFIG_NAMESPACE.get( DEFAULT );
} else {
config = APOLLO_SENTINEL_CONFIG_NAMESPACE.get( profile );
}
getRtAndExceptionRule( config );
getGatewayRule( config );
}
public void initSentinelConfig() {
initApolloListenerConfig(); //初始化apollo的注入config的namespace信息
addApolloConfigChangeListener(); //手动初始化监听器
}
//网关 熔断策略规则
private void getGatewayRule(Config config) {
if (!"".equals( config.getProperty( GATEWAY_CONFIG, "" ) )) {
List<GatewayRuleConfig> gatewayRuleConfigs = JSON.parseArray( config.getProperty( GATEWAY_CONFIG, "" ), GatewayRuleConfig.class );
Set<GatewayFlowRule> rules = new HashSet<>();
for (GatewayRuleConfig gatewayRuleConfig : gatewayRuleConfigs) {
GatewayFlowRule rule = new GatewayFlowRule();
BeanUtils.copyProperties( gatewayRuleConfig,rule );
rules.add( rule );
}
log.info( "SentinelRule apolloHotChange getGatewayRule [{}]", rules );
GatewayRuleManager.loadRules( rules );
}else
GatewayRuleManager.loadRules(null);
}
//RT、EXCEPTION 熔断策略规则
private void getRtAndExceptionRule(Config config) {
if (!"".equals( config.getProperty( RT_EXCEPTION, "" ) )) {
List<ReRuleConfig> reRuleConfigs = JSON.parseArray( config.getProperty( RT_EXCEPTION, "" ), ReRuleConfig.class );
List<DegradeRule> rules = new ArrayList<>();
for (ReRuleConfig reRuleConfig : reRuleConfigs) {
DegradeRule rule = new DegradeRule();
BeanUtils.copyProperties( reRuleConfig,rule );
rule.setLimitApp( "default" );
rules.add( rule );
}
log.info( "SentinelRule apolloHotChange getRtAndExceptionRule [{}]", rules );
DegradeRuleManager.loadRules( rules );
}else
DegradeRuleManager.loadRules( null );
}
@Override
public void setEnvironment(Environment environment) {
this.evn = environment;
// 绑定配置器
binder = Binder.get( evn );
}
}@Slf4j
@Configuration
public class SentinelInitConfig {
@Autowired
private SentinelConfigHotChange sentinelConfigHotChange;
@Value("${spring.cloud.sentinel.transport.dashboard}")
private String sentinel_address;
@Value("${spring.cloud.sentinel.re.config:[]}")
private String reConfig;
@Value("${spring.cloud.sentinel.gateway.config:[]}")
private String gatewayConfig;
private static final ScheduledExecutorService SCHEDULED_EXECUTOR_SERVICE = Executors.newScheduledThreadPool( 1 );
@PostConstruct
public void initSystemConfig() {
//RT、EXCEPTION 熔断策略规则
if (!reConfig.equals( "[]" )) {
getRtAndExceptionRule();
}
//网关流控
if (!gatewayConfig.equals( "[]" )) {
getGatewayRule();
}
registerStateChangeObserver();
//心跳发送自研扩展方式
SentinelMachineRunnable sentinelMachineRunnable = new SentinelMachineRunnable( sentinel_address );
SCHEDULED_EXECUTOR_SERVICE.scheduleAtFixedRate( sentinelMachineRunnable, 1000, 10000, TimeUnit.MILLISECONDS );
sentinelConfigHotChange.initSentinelConfig();
}
/**
* <p>Title:熔断器事件监听</p>
* <p>Description:</p>
* @author QIQI
* @params []
* @return void
* @throws
* @date 2020/10/10 14:00
*/
private static void registerStateChangeObserver() {
EventObserverRegistry.getInstance().addStateChangeObserver( "logging",
(prevState, newState, rule, snapshotValue) -> {
if (newState == CircuitBreaker.State.OPEN) {
log.info( "registerStateChangeObserver:{} -> OPEN at {},snapshotValue = {},rule is {}", prevState.name(),
TimeUtil.currentTimeMillis(), snapshotValue, rule );
} else {
log.error( "registerStateChangeObserver:{} -> {} at {},rule is {}", prevState.name(), newState.name(),
TimeUtil.currentTimeMillis(), rule );
log.error( "registerStateChangeObserver:" + String.format( "%s -> %s at %d", prevState.name(), newState.name(),
TimeUtil.currentTimeMillis() ) );
}
} );
}
//RT、EXCEPTION 熔断策略规则
private void getRtAndExceptionRule() {
List<ReRuleConfig> reRuleConfigs = JSON.parseArray( reConfig, ReRuleConfig.class );
if (Optional.ofNullable( reRuleConfigs ).isPresent()) {
List<DegradeRule> rules = new ArrayList<>();
for (ReRuleConfig reRuleConfig : reRuleConfigs) {
DegradeRule rule = new DegradeRule();
BeanUtils.copyProperties( reRuleConfig,rule );
rule.setLimitApp( "default" );
rules.add( rule );
}
log.info( "SentinelRule init getRtAndExceptionRule [{}]", rules );
DegradeRuleManager.loadRules( rules );
}
}
//网关流控
private void getGatewayRule() {
List<GatewayRuleConfig> gatewayRuleConfigs = JSON.parseArray( gatewayConfig, GatewayRuleConfig.class );
if (Optional.ofNullable( gatewayRuleConfigs ).isPresent()) {
Set<GatewayFlowRule> rules = new HashSet<>();
for (GatewayRuleConfig gatewayRuleConfig : gatewayRuleConfigs) {
GatewayFlowRule rule = new GatewayFlowRule();
BeanUtils.copyProperties( gatewayRuleConfig,rule );
rules.add( rule );
}
log.info( "SentinelRule init getGatewayRule [{}]", rules );
GatewayRuleManager.loadRules( rules );
}
}
}
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