sentinel源码分析-01客户端启动和注册

最新推荐文章于 2024-08-26 12:09:57 发布

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最新推荐文章于 2024-08-26 12:09:57 发布 · 305 阅读

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#sentinel #java

文章详细描述了在SpringBoot应用中集成Sentinel框架的启动过程，包括自动配置类的加载、SentinelFilter的设置，以及客户端通过HeartbeatSender向服务端注册心跳的机制。重点介绍了CommonFilter的过滤逻辑和HeartbeatSender的初始化和心跳发送功能。

1.客户端启动和注册

在引入sentinel组建后，启动时会通过spi机制加载spring.factories文件中的自动配置类

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.alibaba.cloud.sentinel.SentinelWebAutoConfiguration,\
com.alibaba.cloud.sentinel.SentinelWebFluxAutoConfiguration,\
com.alibaba.cloud.sentinel.endpoint.SentinelEndpointAutoConfiguration,\
com.alibaba.cloud.sentinel.custom.SentinelAutoConfiguration,\
com.alibaba.cloud.sentinel.feign.SentinelFeignAutoConfiguration

org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker=\
com.alibaba.cloud.sentinel.custom.SentinelCircuitBreakerConfiguration

SentinelWebAutoConfiguration类中声明了一个FilterRegistrationBean，在这个方法中创建了一个核心类CommonFilter，拦截所有请求

@Bean
@ConditionalOnProperty(
    name = {
   
   "spring.cloud.sentinel.filter.enabled"},
    matchIfMissing = true
)
public FilterRegistrationBean sentinelFilter() {
   
   
    FilterRegistrationBean<Filter> registration = new FilterRegistrationBean();
    com.alibaba.cloud.sentinel.SentinelProperties.Filter filterConfig = this.properties.getFilter();
    if(filterConfig.getUrlPatterns() == null || filterConfig.getUrlPatterns().isEmpty()) {
   
   
        List<String> defaultPatterns = new ArrayList();
        //拦截所有请求
        defaultPatterns.add("/*");
        filterConfig.setUrlPatterns(defaultPatterns);
    }

    registration.addUrlPatterns((String[])filterConfig.getUrlPatterns().toArray(new String[0]));
    Filter filter = new CommonFilter();
    registration.setFilter(filter);
    registration.setOrder(filterConfig.getOrder());
    registration.addInitParameter("HTTP_METHOD_SPECIFY", String.valueOf(this.properties.getHttpMethodSpecify()));
    log.info("[Sentinel Starter] register Sentinel CommonFilter with urlPatterns: {}.", filterConfig.getUrlPatterns());
    return registration;
}

查看CommonFilter.doFilter方法

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
        throws IOException, ServletException {
   
   
    //拦截过滤
    HttpServletRequest sRequest = (HttpServletRequest) request;
    Entry urlEntry = null;
    Entry httpMethodUrl