zuul动态配置路由规则,从DB读取

2017-09-11 15:34 出处:csdn 人气: 评论(0

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

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);
    }

    //父类已经提供了这个方法,这里写出来只是为了说明这一个方法很重要!!!
//    @Override
//    protected void doRefresh() {
//        super.doRefresh();
//    }


    @Override
    public void refresh() {
        doRefresh();
    }

    @Override
    protected Map<String, ZuulProperties.ZuulRoute> locateRoutes() {
        LinkedHashMap<String, ZuulProperties.ZuulRoute> routesMap = new LinkedHashMap<>();
        //从application.properties中加载路由信息
        routesMap.putAll(super.locateRoutes());
        //从db中加载路由信息
        routesMap.putAll(locateRoutesFromDB());
        //优化一下配置
        LinkedHashMap<String, ZuulProperties.ZuulRoute> values = new LinkedHashMap<>();
        for (Map.Entry<String, ZuulProperties.ZuulRoute> entry : routesMap.entrySet()) {
            String path = entry.getKey();
            // Prepend with slash if not already present.
            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()) || 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 {

        /**
         * The ID of the route (the same as its map key by default).
         */
        private String id;

        /**
         * The path (pattern) for the route, e.g. /foo/**.
         */
        private String path;

        /**
         * The service ID (if any) to map to this route. You can specify a physical URL or
         * a service, but not both.
         */
        private String serviceId;

        /**
         * A full physical URL to map to the route. An alternative is to use a service ID
         * and service discovery to find the physical address.
         */
        private String url;

        /**
         * Flag to determine whether the prefix for this route (the path, minus pattern
         * patcher) should be stripped before forwarding.
         */
        private boolean stripPrefix = true;

        /**
         * Flag to indicate that this route should be retryable (if supported). Generally
         * retry requires a service ID and ribbon.
         */
        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 ('xxxx', '/xxxx/**', 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。

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。经测试是正常的。


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。





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