nacos+ribbon自定义ab测试路由策略

原理：通过请求头埋入指定服务的metadata标识，扩展ribbon的choose策略。

传送门

• 下载源码编译

应用集成

maven依赖

<dependency>
  <groupId>io.jmnarloch</groupId> 
  <artifactId>ribbon-discovery-filter-spring-cloud-starter</artifactId>
  <version>2.1.0</version>
</dependency>

• 应用配置

#AB测试用，网关会根据该参数路由
spring.cloud.nacos.discovery.metadata.launcher=A

• 拦截器

public class AbTestingFilter extends OncePerRequestFilter {
    private final static String SWITCH_KEY = "launcher",
            SWITCH_HEAD_KEY = "switchTag",
            DEFAULT_ENV = "B";//默认B为线上测试环境

    @Override
    protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException {
        String switchTag = httpServletRequest.getHeader(SWITCH_HEAD_KEY);
        log.info("head switch tag = {}", switchTag);
        try {
            if (DEFAULT_ENV.equals(switchTag)) {
                // 开启ribbon的灰度开关（线程级别）
                RibbonFilterContextHolder.getCurrentContext().add(SWITCH_KEY, DEFAULT_ENV);
            }
            filterChain.doFilter(httpServletRequest, httpServletResponse);
        } finally {
            if (DEFAULT_ENV.equals(switchTag))
                RibbonFilterContextHolder.getCurrentContext().remove(SWITCH_KEY);
        }
    }
}

• feign conf
  增加请求头,自定义全局的feign interceptor

    @Bean
    public RequestInterceptor newRequestInterceptor(@Value("${spring.cloud.nacos.discovery.metadata.launcher:A}") String tag) {
        return requestTemplate -> requestTemplate.header("switchTag", tag);
    }

zuul网关集成

则参考如下代码

maven依赖同上

拦截器

public class TestingAbFilter extends ZuulFilter {

    @Override
    public String filterType() {
        return FilterConstants.PRE_TYPE;
    }

    @Override
    public int filterOrder() {
        return -1;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() throws ZuulException {
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        //是否需要做AB切换
        if (request.getParameter("foo") != null) {
            //重写请求头新增AB开关透传到下游服务
            ctx.addZuulRequestHeader("switchTag", "A");
            RibbonFilterContextHolder.getCurrentContext().add("launcher", "A");
        } else {
            RibbonFilterContextHolder.getCurrentContext().add("launcher", "B");
        }
        return null;
    }
}