zuul动态配置路由规则,从DB读取
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前面已经讲过zuul在application.yml里配置路由规则,将用户请求分发至不同微服务的例子。
zuul作为一个网关,是用户请求的入口,担当鉴权、转发的重任,理应保持高可用性和具备动态配置的能力。
我画了一个实际中可能使用的配置框架,如图。
当用户发起请求后,首先通过并发能力强、能承担更多用户请求的负载均衡器进行第一步的负载均衡,将大量的请求分发至多个网关服务。这是分布式的第一步。如果是使用docker的话,并且使用rancher进行docker管理,那么可以很简单的使用rancher自带的负载均衡,创建HaProxy,将请求分发至多个Zuul的docker容器。使用多个zuul的原因即是避免单点故障,由于网关非常重要,尽量配置多个实例。
然后在Zuul网关中,执行完自定义的网关职责后,将请求转发至另一个HaProxy负载的微服务集群,同样是避免微服务单点故障和性能瓶颈。
最后由具体的微服务处理用户请求并返回结果。
那么为什么要设置zuul的动态配置呢,因为网关其特殊性,我们不希望它重启再加载新的配置,而且如果能实时动态配置,我们就可以完成无感知的微服务迁移替换,在某种程度还可以完成服务降级的功能。
zuul的动态配置也很简单,这里我们参考http://blog.csdn.net/u013815546/article/details/68944039 并使用他的方法,从数据库读取配置信息,刷新配置。
看实现类
配置文件里我们可以不配置zuul的任何路由,全部交给数据库配置。
- package com.tianyalei.testzuul.config;
-
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- import org.springframework.beans.BeanUtils;
- import org.springframework.cloud.netflix.zuul.filters.RefreshableRouteLocator;
- import org.springframework.cloud.netflix.zuul.filters.SimpleRouteLocator;
- import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
- import org.springframework.jdbc.core.BeanPropertyRowMapper;
- import org.springframework.jdbc.core.JdbcTemplate;
- import org.springframework.util.StringUtils;
-
- import java.util.LinkedHashMap;
- import java.util.List;
- import java.util.Map;
-
- public class CustomRouteLocator extends SimpleRouteLocator implements RefreshableRouteLocator {
-
- public final static Logger logger = LoggerFactory.getLogger(CustomRouteLocator.class);
-
- private JdbcTemplate jdbcTemplate;
-
- private ZuulProperties properties;
-
- public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
- this.jdbcTemplate = jdbcTemplate;
- }
-
- public CustomRouteLocator(String servletPath, ZuulProperties properties) {
- super(servletPath, properties);
- this.properties = properties;
- logger.info("servletPath:{}", servletPath);
- }
-
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- @Override
- public void refresh() {
- doRefresh();
- }
-
- @Override
- protected Map<String, ZuulProperties.ZuulRoute> locateRoutes() {
- LinkedHashMap<String, ZuulProperties.ZuulRoute> routesMap = new LinkedHashMap<>();
-
- routesMap.putAll(super.locateRoutes());
-
- routesMap.putAll(locateRoutesFromDB());
-
- LinkedHashMap<String, ZuulProperties.ZuulRoute> values = new LinkedHashMap<>();
- for (Map.Entry<String, ZuulProperties.ZuulRoute> entry : routesMap.entrySet()) {
- String path = entry.getKey();
-
- if (!path.startsWith("/")) {
- path = "/" + path;
- }
- if (StringUtils.hasText(this.properties.getPrefix())) {
- path = this.properties.getPrefix() + path;
- if (!path.startsWith("/")) {
- path = "/" + path;
- }
- }
- values.put(path, entry.getValue());
- }
- return values;
- }
-
- private Map<String, ZuulProperties.ZuulRoute> locateRoutesFromDB() {
- Map<String, ZuulProperties.ZuulRoute> routes = new LinkedHashMap<>();
- List<ZuulRouteVO> results = jdbcTemplate.query("select * from gateway_api_define where enabled = true ", new
- BeanPropertyRowMapper<>(ZuulRouteVO.class));
- for (ZuulRouteVO result : results) {
- if (StringUtils.isEmpty(result.getPath()) ) {
- continue;
- }
- if (StringUtils.isEmpty(result.getServiceId()) && StringUtils.isEmpty(result.getUrl())) {
- continue;
- }
- ZuulProperties.ZuulRoute zuulRoute = new ZuulProperties.ZuulRoute();
- try {
- BeanUtils.copyProperties(result, zuulRoute);
- } catch (Exception e) {
- logger.error("=============load zuul route info from db with error==============", e);
- }
- routes.put(zuulRoute.getPath(), zuulRoute);
- }
- return routes;
- }
-
- public static class ZuulRouteVO {
-
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- private String id;
-
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- private String path;
-
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- private String serviceId;
-
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-
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- private String url;
-
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-
-
- private boolean stripPrefix = true;
-
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-
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- private Boolean retryable;
-
- private Boolean enabled;
-
- public String getId() {
- return id;
- }
-
- public void setId(String id) {
- this.id = id;
- }
-
- public String getPath() {
- return path;
- }
-
- public void setPath(String path) {
- this.path = path;
- }
-
- public String getServiceId() {
- return serviceId;
- }
-
- public void setServiceId(String serviceId) {
- this.serviceId = serviceId;
- }
-
- public String getUrl() {
- return url;
- }
-
- public void setUrl(String url) {
- this.url = url;
- }
-
- public boolean isStripPrefix() {
- return stripPrefix;
- }
-
- public void setStripPrefix(boolean stripPrefix) {
- this.stripPrefix = stripPrefix;
- }
-
- public Boolean getRetryable() {
- return retryable;
- }
-
- public void setRetryable(Boolean retryable) {
- this.retryable = retryable;
- }
-
- public Boolean getEnabled() {
- return enabled;
- }
-
- public void setEnabled(Boolean enabled) {
- this.enabled = enabled;
- }
- }
- }
- package com.tianyalei.testzuul.config;
-
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.boot.autoconfigure.web.ServerProperties;
- import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
- import org.springframework.context.annotation.Bean;
- import org.springframework.context.annotation.Configuration;
- import org.springframework.jdbc.core.JdbcTemplate;
-
- @Configuration
- public class CustomZuulConfig {
-
- @Autowired
- ZuulProperties zuulProperties;
- @Autowired
- ServerProperties server;
- @Autowired
- JdbcTemplate jdbcTemplate;
-
- @Bean
- public CustomRouteLocator routeLocator() {
- CustomRouteLocator routeLocator = new CustomRouteLocator(this.server.getServletPrefix(), this.zuulProperties);
- routeLocator.setJdbcTemplate(jdbcTemplate);
- return routeLocator;
- }
-
- }
下面的config类功能就是使用自定义的RouteLocator类,上面的类就是这个自定义类。里面主要是一个方法,locateRoutes方法,该方法就是zuul设置路由规则的地方,在方法里做了2件事,一是从application.yml读取配置的路由信息,二是从数据库里读取路由信息,所以数据库里需要一个各字段和ZuulProperties.ZuulRoute一样的表,存储路由信息,从数据库读取后添加到系统的Map<String, ZuulProperties.ZuulRoute>中。
在实际的路由中,zuul就是按照Map<String, ZuulProperties.ZuulRoute>里的信息进行路由转发的。
建表语句:
- create table `gateway_api_define` (
- `id` varchar(50) not null,
- `path` varchar(255) not null,
- `service_id` varchar(50) default null,
- `url` varchar(255) default null,
- `retryable` tinyint(1) default null,
- `enabled` tinyint(1) not null,
- `strip_prefix` int(11) default null,
- `api_name` varchar(255) default null,
- primary key (`id`)
- ) engine=innodb default charset=utf8
-
-
- INSERT INTO gateway_api_define (id, path, service_id, retryable, strip_prefix, url, enabled) VALUES ('user', '/user/**', null,0,1, 'http://localhost:8081', 1);
- INSERT INTO gateway_api_define (id, path, service_id, retryable, strip_prefix, url, enabled) VALUES ('club', '/club/**', null,0,1, 'http://localhost:8090', 1);
通过上面的两个类,再结合前面几篇讲过的zuul的使用,就可以自行测试一下在数据库里配置的信息能否在zuul中生效了。
数据库里的各字段分别对应原本在yml里配置的同名属性,如path,service_id,url等,等于把配置文件存到数据库里。
至于修改数据库值信息后(增删改),让zuul动态生效需要借助于下面的方法
- package com.tianyalei.testzuul.config;
-
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.cloud.netflix.zuul.RoutesRefreshedEvent;
- import org.springframework.cloud.netflix.zuul.filters.RouteLocator;
- import org.springframework.context.ApplicationEventPublisher;
- import org.springframework.stereotype.Service;
-
- @Service
- public class RefreshRouteService {
- @Autowired
- ApplicationEventPublisher publisher;
-
- @Autowired
- RouteLocator routeLocator;
-
- public void refreshRoute() {
- RoutesRefreshedEvent routesRefreshedEvent = new RoutesRefreshedEvent(routeLocator);
- publisher.publishEvent(routesRefreshedEvent);
- }
- }
可以定义一个Controller,在Controller里调用refreshRoute方法即可,zuul就会重新加载一遍路由信息,完成刷新功能。通过修改数据库,然后刷新,经测试是正常的。- @RestController
- public class RefreshController {
- @Autowired
- RefreshRouteService refreshRouteService;
- @Autowired
- ZuulHandlerMapping zuulHandlerMapping;
-
- @GetMapping("/refreshRoute")
- public String refresh() {
- refreshRouteService.refreshRoute();
- return "refresh success";
- }
-
- @RequestMapping("/watchRoute")
- public Object watchNowRoute() {
-
- Map<String, Object> handlerMap = zuulHandlerMapping.getHandlerMap();
- return handlerMap;
- }
-
- }
参考http://blog.csdn.net/u013815546/article/details/68944039,作者从源码角度讲解了动态配置的使用。