Spring Cloud Zuul实现动态路由

超、凢脫俗 2022-05-22 07:50 215阅读 0赞

大致看看 ,看个思路即可

转载:https://mp.weixin.qq.com/s/4d-epBiq5b69fZTCSkiOzA

Zuul 是Netflix 提供的一个开源组件,致力于在云平台上提供动态路由，监控，弹性，安全等边缘服务的框架。也有很多公司使用它来作为网关的重要组成部分，碰巧今年公司的架构组决定自研一个网关产品，集动态路由，动态权限，限流配额等功能为一体，为其他部门的项目提供统一的外网调用管理，最终形成产品(这方面阿里其实已经有成熟的网关产品了，但是不太适用于个性化的配置，也没有集成权限和限流降级)。

不过这里并不想介绍整个网关的架构，而是想着重于讨论其中的一个关键点，并且也是经常在交流群中听人说起的：动态路由怎么做？

再阐释什么是动态路由之前，需要介绍一下架构的设计。

传统互联网架构图

![640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1][]

上图是没有网关参与的一个最典型的互联网架构(本文中统一使用book代表应用实例，即真正提供服务的一个业务系统)

加入eureka的架构图

![640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1 1][]

book注册到eureka注册中心中，zuul本身也连接着同一个eureka，可以拉取book众多实例的列表。服务中心的注册发现一直是值得推崇的一种方式，但是不适用与网关产品。因为我们的网关是面向众多的其他部门的已有或是异构架构的系统，不应该强求其他系统都使用eureka，这样是有侵入性的设计。

最终架构图

![640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1 2][]

要强调的一点是，gateway最终也会部署多个实例，达到分布式的效果，在架构图中没有画出，请大家自行脑补。

本文示例使用最后一章架构图为例，带来动态路由的实现方式，会有具体的代码。

动态路由

动态路由需要达到可持久化配置，动态刷新的效果。如架构图所示，不仅要能满足从spring的配置文件properties加载路由信息，还需要从数据库加载我们的配置。另外一点是，路由信息在容器启动时就已经加载进入了内存，我们希望配置完成后，实施发布，动态刷新内存中的路由信息，达到不停机维护路由信息的效果。

zuul–HelloWorldDemo

项目结构

<groupId>com.sinosoft</groupId>

<artifactId>zuul-gateway-demo</artifactId>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>1.5.2.RELEASE</version>

</parent>

<module>gateway</module>

</modules>

<groupId>org.springframework.cloud</groupId>

<artifactId>spring-cloud-dependencies</artifactId>

<version>Camden.SR6</version>

<scope>import</scope>

</dependency>

</dependencies>

</dependencyManagement>

tip：springboot-1.5.2对应的springcloud的版本需要使用Camden.SR6，一开始想专门写这个demo时，只替换了springboot的版本1.4.0->1.5.2，结果启动就报错了，最后发现是版本不兼容的锅。

gateway项目：

启动类：GatewayApplication.Java

@EnableZuulProxy

@SpringBootApplication

public class GatewayApplication \{

public static void main(String\[\] args) \{

SpringApplication.run(GatewayApplication.class, args);

配置：application.properties

\#配置在配置文件中的路由信息zuul.routes.books.url=http://localhost:8090zuul.routes.books.path=/books/\*\*\#不使用注册中心,会带来侵入性ribbon.eureka.enabled=false\#网关端口server.port=8080

book项目：   
启动类：BookApplication.java

@RestController

@SpringBootApplication

public class BookApplication \{

@RequestMapping(value = "/available")

public String available() \{

System.out.println("Spring in Action");

return "Spring in Action";

@RequestMapping(value = "/checked-out")

public String checkedOut() \{

return "Spring Boot in Action";

public static void main(String\[\] args) \{

SpringApplication.run(BookApplication.class, args);

配置类：application.properties

server.port=8090

测试访问：http://localhost:8080/books/available

上述demo是一个简单的静态路由，简单看下源码，zuul是怎么做到转发，路由的。

@Configuration

@EnableConfigurationProperties(\{ZuulProperties.class

\})

@ConditionalOnClass(ZuulServlet.class)

@Import(ServerPropertiesAutoConfiguration.class)

public class ZuulConfiguration \{

@Autowired

//zuul的配置文件,对应了application.properties中的配置信息

protected ZuulProperties zuulProperties;

@Autowired

protected ServerProperties server;

@Autowired(required = false)

private ErrorController errorController;

@Bean

public HasFeatures zuulFeature() \{

return HasFeatures.namedFeature("Zuul (Simple)", ZuulConfiguration.class);

//核心类，路由定位器，最最重要

@Bean

@ConditionalOnMissingBean(RouteLocator.class)

public RouteLocator routeLocator() \{

//默认配置的实现是SimpleRouteLocator.class

return new SimpleRouteLocator(this.server.getServletPrefix(),

this.zuulProperties);

//zuul的控制器，负责处理链路调用

@Bean

public ZuulController zuulController() \{

return new ZuulController();

//MVC HandlerMapping that maps incoming request paths to remote services.

@Bean

public ZuulHandlerMapping zuulHandlerMapping(RouteLocator routes) \{

ZuulHandlerMapping mapping = new ZuulHandlerMapping(routes,

zuulController());

mapping.setErrorController(this.errorController);

return mapping;

//注册了一个路由刷新监听器，默认实现是ZuulRefreshListener.class，这个是我们动态路由的关键

@Bean

public ApplicationListener<ApplicationEvent> zuulRefreshRoutesListener() \{

return new ZuulRefreshListener();

@Bean

@ConditionalOnMissingBean(name = "zuulServlet")

public ServletRegistrationBean zuulServlet() \{

ServletRegistrationBean servlet = new ServletRegistrationBean(new ZuulServlet(),

this.zuulProperties.getServletPattern());

// The whole point of exposing this servlet is to provide a route that doesn't

// buffer requests.

servlet.addInitParameter("buffer-requests", "false");

return servlet;

// pre filters

@Bean

public ServletDetectionFilter servletDetectionFilter() \{

return new ServletDetectionFilter();

@Bean

public FormBodyWrapperFilter formBodyWrapperFilter() \{

return new FormBodyWrapperFilter();

@Bean

public DebugFilter debugFilter() \{

return new DebugFilter();

@Bean

public Servlet30WrapperFilter servlet30WrapperFilter() \{

return new Servlet30WrapperFilter();

// post filters

@Bean

public SendResponseFilter sendResponseFilter() \{

return new SendResponseFilter();

@Bean

public SendErrorFilter sendErrorFilter() \{

return new SendErrorFilter();

@Bean

public SendForwardFilter sendForwardFilter() \{

return new SendForwardFilter();

@Configuration

protected static class ZuulFilterConfiguration \{

@Autowired

private Map<String, ZuulFilter> filters;

@Bean

public ZuulFilterInitializer zuulFilterInitializer() \{

return new ZuulFilterInitializer(this.filters);

//上面提到的路由刷新监听器

private static class ZuulRefreshListener implements ApplicationListener<ApplicationEvent> \{

@Autowired

private ZuulHandlerMapping zuulHandlerMapping;

private HeartbeatMonitor heartbeatMonitor = new HeartbeatMonitor();

@Override

public void onApplicationEvent(ApplicationEvent event) \{

if (event instanceof ContextRefreshedEvent ||

event instanceof RefreshScopeRefreshedEvent                ||   event instanceof RoutesRefreshedEvent) \{

//设置为脏,下一次匹配到路径时，如果发现为脏，则会去刷新路由信息

this.zuulHandlerMapping.setDirty(true);

\} else if (event instanceof HeartbeatEvent) \{

if (this.heartbeatMonitor.update(

((HeartbeatEvent) event).getValue())) \{

this.zuulHandlerMapping.setDirty(true);

我们要解决动态路由的难题，第一步就得理解路由定位器的作用。

![640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1 3][]

很失望，因为从接口关系来看，spring考虑到了路由刷新的需求，但是默认实现的SimpleRouteLocator没有实现RefreshableRouteLocator接口，看来我们只能借鉴DiscoveryClientRouteLocator去改造SimpleRouteLocator使其具备刷新能力。

public interface RefreshableRouteLocator extends RouteLocator \{

void refresh();

DiscoveryClientRouteLocator比SimpleRouteLocator多了两个功能，第一是从DiscoveryClient（如Eureka）发现路由信息，之前的架构图已经给大家解释清楚了，我们不想使用eureka这种侵入式的网关模块，所以忽略它，第二是实现了RefreshableRouteLocator接口，能够实现动态刷新。

对SimpleRouteLocator.class的源码加一些注释，方便大家阅读：

public class SimpleRouteLocator implements RouteLocator \{

//配置文件中的路由信息配置

private ZuulProperties properties;

//路径正则配置器,即作用于path:/books/\*\*

private PathMatcher pathMatcher = new AntPathMatcher();

private String dispatcherServletPath = "/";

private String zuulServletPath;

private AtomicReference<Map<String, ZuulRoute>> routes = new AtomicReference<>();

public SimpleRouteLocator(String servletPath, ZuulProperties properties) \{

this.properties = properties;

if (servletPath != null && StringUtils.hasText(servletPath)) \{

this.dispatcherServletPath = servletPath;

this.zuulServletPath = properties.getServletPath();

//路由定位器和其他组件的交互，是最终把定位的Routes以list的方式提供出去,核心实现

@Override

public List<Route> getRoutes() \{

if (this.routes.get() == null) \{

this.routes.set(locateRoutes());

List<Route> values = new ArrayList<>();

for (String url : this.routes.get().keySet()) \{

ZuulRoute route = this.routes.get().get(url);

String path = route.getPath();

values.add(getRoute(route, path));

return values;

@Override

public Collection<String> getIgnoredPaths() \{

return this.properties.getIgnoredPatterns();

//这个方法在网关产品中也很重要，可以根据实际路径匹配到Route来进行业务逻辑的操作，进行一些加工

@Override

public Route getMatchingRoute(final String path) \{

if (log.isDebugEnabled()) \{

log.debug("Finding route for path: " + path);

if (this.routes.get() == null) \{

this.routes.set(locateRoutes());

if (log.isDebugEnabled()) \{

log.debug("servletPath=" + this.dispatcherServletPath);

log.debug("zuulServletPath=" + this.zuulServletPath);

log.debug("RequestUtils.isDispatcherServletRequest()="

+ RequestUtils.isDispatcherServletRequest());

log.debug("RequestUtils.isZuulServletRequest()="

+ RequestUtils.isZuulServletRequest());

String adjustedPath = adjustPath(path);

ZuulRoute route = null;

if (!matchesIgnoredPatterns(adjustedPath)) \{

for (Entry<String, ZuulRoute> entry : this.routes.get().entrySet()) \{

String pattern = entry.getKey();

log.debug("Matching pattern:" + pattern);

if (this.pathMatcher.match(pattern, adjustedPath)) \{

route = entry.getValue();

break;

if (log.isDebugEnabled()) \{

log.debug("route matched=" + route);

return getRoute(route, adjustedPath);

private Route getRoute(ZuulRoute route, String path) \{

if (route == null) \{

return null;

String targetPath = path;

String prefix = this.properties.getPrefix();

if (path.startsWith(prefix) && this.properties.isStripPrefix()) \{

targetPath = path.substring(prefix.length());

if (route.isStripPrefix()) \{

int index = route.getPath().indexOf("\*") - 1;

if (index > 0) \{

String routePrefix = route.getPath().substring(0, index);

targetPath = targetPath.replaceFirst(routePrefix, "");

prefix = prefix + routePrefix;

Boolean retryable = this.properties.getRetryable();

if (route.getRetryable() != null) \{

retryable = route.getRetryable();

return new Route(route.getId(), targetPath, route.getLocation(), prefix,

retryable,

route.isCustomSensitiveHeaders() ? route.getSensitiveHeaders() : null);

//注意这个类并没有实现refresh接口，但是却提供了一个protected级别的方法,旨在让子类不需要重复维护一个private AtomicReference<Map<String, ZuulRoute>> routes = new AtomicReference<>();也可以达到刷新的效果

protected void doRefresh() \{

this.routes.set(locateRoutes());

//具体就是在这儿定位路由信息的，我们之后从数据库加载路由信息，主要也是从这儿改写

/\*\*

\* Compute a map of path pattern to route. The default is just a static map from the

\* \{@link ZuulProperties\}, but subclasses can add dynamic calculations.

\*/

protected Map<String, ZuulRoute> locateRoutes() \{

LinkedHashMap<String, ZuulRoute> routesMap = new LinkedHashMap<String, ZuulRoute>();

for (ZuulRoute route : this.properties.getRoutes().values()) \{

routesMap.put(route.getPath(), route);

return routesMap;

protected boolean matchesIgnoredPatterns(String path) \{

for (String pattern : this.properties.getIgnoredPatterns()) \{

log.debug("Matching ignored pattern:" + pattern);

if (this.pathMatcher.match(pattern, path)) \{

log.debug("Path " + path + " matches ignored pattern " + pattern);

return true;

return false;

private String adjustPath(final String path) \{

String adjustedPath = path;

if (RequestUtils.isDispatcherServletRequest()

&& StringUtils.hasText(this.dispatcherServletPath)) \{

if (!this.dispatcherServletPath.equals("/")) \{

adjustedPath = path.substring(this.dispatcherServletPath.length());

log.debug("Stripped dispatcherServletPath");

else if (RequestUtils.isZuulServletRequest()) \{

if (StringUtils.hasText(this.zuulServletPath)

&& !this.zuulServletPath.equals("/")) \{

adjustedPath = path.substring(this.zuulServletPath.length());

log.debug("Stripped zuulServletPath");

else \{

// do nothing

log.debug("adjustedPath=" + path);

return adjustedPath;

重写过后的自定义路由定位器如下：

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, ZuulRoute> locateRoutes() \{

LinkedHashMap<String, ZuulRoute> routesMap = new LinkedHashMap<String, ZuulRoute>();

//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, ZuulRoute> values = new LinkedHashMap<>();

for (Map.Entry<String, 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, ZuulRoute> locateRoutesFromDB()\{

Map<String, 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(org.apache.commons.lang3.StringUtils.isBlank(result.getPath()) || org.apache.commons.lang3.StringUtils.isBlank(result.getUrl()) )\{

continue;

ZuulRoute zuulRoute = new ZuulRoute();

try \{

org.springframework.beans.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;

配置这个自定义的路由定位器：

@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;

现在容器启动时，就可以从数据库和配置文件中一起加载路由信息了，离动态路由还差最后一步，就是实时刷新，前面已经说过了，默认的ZuulConfigure已经配置了事件监听器，我们只需要发送一个事件就可以实现刷新了。

public class RefreshRouteService \{

@Autowired

ApplicationEventPublisher publisher;

@Autowired

RouteLocator routeLocator;

public void refreshRoute() \{

RoutesRefreshedEvent routesRefreshedEvent = new RoutesRefreshedEvent(routeLocator);

publisher.publishEvent(routesRefreshedEvent);

具体的刷新流程其实就是从数据库重新加载了一遍，有人可能会问，为什么不自己是手动重新加载Locator.dorefresh？非要用事件去刷新。这牵扯到内部的zuul内部组件的工作流程，不仅仅是Locator本身的一个变量，具体想要了解的还得去看源码。

到这儿我们就实现了动态路由了，所以的实例代码和建表语句我会放到github上，下载的时候记得给我star QAQ ！！！

链接：https://github.com/lexburner/zuul-gateway-demo

[640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1]: /images/20220522/e8641ce0c6634f60b812859da1a6d32d.png
[640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1 1]: /images/20220522/bacc6806a1424ce9aafce83d1d5d7191.png
[640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1 2]: /images/20220522/4a3d412c1b144bb193be5c67aad381b0.png
[640_wx_fmt_png_tp_webp_wxfrom_5_wx_lazy_1 3]: /images/20220522/62dea8624cb2475e8e11cccca3e62b4a.png