第三章 网关zuul搭建
前言：
1、主要功能
zuul主要提供动态路由（内置ribbon实现）和过滤（可以做统一鉴权过滤器、灰度发布过滤器、黑白名单IP过滤器、服务限流过滤器（可以配合Sentinel实现））功能；
2、和Spring Cloud GateWay的区别
属于两个不同开源组织提供的网关解决方案。spring cloud GateWay使用非阻塞API，内置限流过滤器，支持长连接（比如 websockets），在高并发和后端服务响应慢的场景下比Zuul1的表现要好；zuul无内置限流过滤器，但是可以与Sentinel（是阿里开源的一款高性能的限流框架）集成使用。
一、创建zuul服务module
参考第二章eureka的创建
二、配置文件
1、pom文件配置
XML
<?xml version="1.0"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.hq</groupId>
<artifactId>taxi-online</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>taxi-online-zuul</artifactId>
<name>taxi-online-zuul</name>
<description>personal test for zuul</description>
<url>org.apache</url>
<packaging>jar</packaging>
<dependencies>
<!-- zuul -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-zuul</artifactId>
</dependency>
<!-- eureka-client -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
</dependencies>
</project>2、application.yml文件配置
XML
#服务端口
server:
port: 9100
#服务名
spring:
application:
name: taxi-online-zuul
#服务注册
eureka:
client:
service-url:
defaultZone: http://localhost:9001/eureka/,http://localhost:9002/eureka/
enabled: true # 是否启用Eureka client
instance:
hostname: localhost
instance-id: taxi-online-zuul # 实例id3、启动类
java
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
@SpringBootApplication
@EnableZuulProxy
@EnableEurekaClient
public class StartSpringCloudZuul {
public static void main(String[] args) {
SpringApplication.run(StartSpringCloudZuul.class,args);
}
}三、zuul功能
1、动态路由
2、统一鉴权
3、过滤器
4、灰度发布
5、限流
四、底层源码
1、启动原理
类似注册中心：
1）boot启动类
boot启动类上添加@EnableZuulProxy注解；
2）EnableZuulProxy注解
EnableZuulProxy注解中导入ZuulProxyMarkerConfiguration配置类
java
@EnableCircuitBreaker
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Import(ZuulProxyMarkerConfiguration.class)
public @interface EnableZuulProxy {
}3）ZuulProxyMarkerConfiguration配置类
ZuulProxyMarkerConfiguration配置类往容器添加了一个空的Marker对象，这个对象是作为容器是否添加ZuulProxyAutoConfiguration类的条件，因为ZuulProxyAutoConfiguration类上面加了@ConditionalOnBean(ZuulProxyMarkerConfiguration.Marker.class)的注解
java
@Configuration(proxyBeanMethods = false)
public class ZuulProxyMarkerConfiguration {
@Bean
public Marker zuulProxyMarkerBean() {
return new Marker();
}
class Marker {
}
}4）spring.factories文件
zuul包下面的spring.factories文件指定了两个引入类，只要导包就会被引进去（由SpringFactoriesLoader 进行读取）--见下方截图。如果没有这个文件，boot的自动扫描不会扫描这些外部包的类。这两个引入类被注入容器的条件分别是:
@ConditionalOnBean(ZuulServerMarkerConfiguration.Marker.class)
@ConditionalOnBean(ZuulProxyMarkerConfiguration.Marker.class)
，分别可以通过在启动类上添加下面注解来引入相应的Marker类：
@EnableZuulProxy
@EnableZuulServer。
@EnableZuulServer、@EnableZuulProxy两个注解的区别：
@EnableZuulServer - 普通Zuul Server,只支持基本的route与filter功能.
@EnableZuulProxy - 普通Zuul Server+服务发现与熔断等功能的增强版,具有反向代理功能。
@EnableZuulProxy简单理解为@EnableZuulServer的增强版，当Zuul与Eureka、Ribbon等组件配合使用时，我们使用@EnableZuulProxy。所以我们做SpringCloud微服务系统一般都是使用@EnableZuulProxy。
5）ZuulServerAutoConfiguration配置类
ZuulServerAutoConfiguration配置类（源码见下方）主要做的事情有：
1、往容器注入了ZuulServlet，该类是zuul的核心类。
2、往容器注入了 一些前置过滤器和后置过滤器。
3、注入ZuulFilterInitializer类并初始化，初始化逻辑中将所有过滤器交给FilterRegistry类进行管理。FilterRegistry类源码如下：
java
/**
* @author mhawthorne
*/
public class FilterRegistry {
private static final FilterRegistry INSTANCE = new FilterRegistry();
public static final FilterRegistry instance() {
return INSTANCE;
}
private final ConcurrentHashMap<String, ZuulFilter> filters = new ConcurrentHashMap<String, ZuulFilter>();
private FilterRegistry() {
}
public ZuulFilter remove(String key) {
return this.filters.remove(key);
}
public ZuulFilter get(String key) {
return this.filters.get(key);
}
public void put(String key, ZuulFilter filter) {
this.filters.putIfAbsent(key, filter);
}
public int size() {
return this.filters.size();
}
public Collection<ZuulFilter> getAllFilters() {
return this.filters.values();
}
}ZuulServerAutoConfiguration源码如下（有删减）：
java
/**
* @author Spencer Gibb
* @author Dave Syer
* @author Biju Kunjummen
*/
@Configuration(proxyBeanMethods = false)
@EnableConfigurationProperties({ ZuulProperties.class })
@ConditionalOnClass({ ZuulServlet.class, ZuulServletFilter.class })
@ConditionalOnBean(ZuulServerMarkerConfiguration.Marker.class)
// Make sure to get the ServerProperties from the same place as a normal web app would
// FIXME @Import(ServerPropertiesAutoConfiguration.class)
public class ZuulServerAutoConfiguration {
@Bean
@ConditionalOnMissingBean(name = "zuulServlet")
@ConditionalOnProperty(name = "zuul.use-filter", havingValue = "false",
matchIfMissing = true)
public ServletRegistrationBean zuulServlet() {
ServletRegistrationBean<ZuulServlet> 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
@ConditionalOnMissingBean
public FormBodyWrapperFilter formBodyWrapperFilter() {
return new FormBodyWrapperFilter();
}
@Bean
@ConditionalOnMissingBean
public DebugFilter debugFilter() {
return new DebugFilter();
}
@Bean
@ConditionalOnMissingBean
public Servlet30WrapperFilter servlet30WrapperFilter() {
return new Servlet30WrapperFilter();
}
// post filters
@Bean
public SendResponseFilter sendResponseFilter(ZuulProperties properties) {
return new SendResponseFilter(zuulProperties);
}
@Bean
public SendErrorFilter sendErrorFilter() {
return new SendErrorFilter();
}
@Bean
public SendForwardFilter sendForwardFilter() {
return new SendForwardFilter();
}
//
@Configuration(proxyBeanMethods = false)
protected static class ZuulFilterConfiguration {
@Autowired
private Map<String, ZuulFilter> filters;
@Bean
public ZuulFilterInitializer zuulFilterInitializer(CounterFactory counterFactory,
TracerFactory tracerFactory) {
FilterLoader filterLoader = FilterLoader.getInstance();
FilterRegistry filterRegistry = FilterRegistry.instance();
return new ZuulFilterInitializer(this.filters, counterFactory, tracerFactory,
filterLoader, filterRegistry);
}
}
}6)ZuulProxyAutoConfiguration配置类
继承了ZuulServerAutoConfiguration类，是ZuulServerAutoConfiguration的增强版，在ZuulServerAutoConfiguration的基础上增加eureka、ribbon、hystrix等功能。源码如下：
java
/**
* @author Spencer Gibb
* @author Dave Syer
* @author Biju Kunjummen
*/
@Configuration(proxyBeanMethods = false)
@Import({ RibbonCommandFactoryConfiguration.RestClientRibbonConfiguration.class,
RibbonCommandFactoryConfiguration.OkHttpRibbonConfiguration.class,
RibbonCommandFactoryConfiguration.HttpClientRibbonConfiguration.class,
HttpClientConfiguration.class })
@ConditionalOnBean(ZuulProxyMarkerConfiguration.Marker.class)
public class ZuulProxyAutoConfiguration extends ZuulServerAutoConfiguration {
// pre filters
@Bean
@ConditionalOnMissingBean(PreDecorationFilter.class)
public PreDecorationFilter preDecorationFilter(RouteLocator routeLocator,
ProxyRequestHelper proxyRequestHelper) {
return new PreDecorationFilter(routeLocator,
this.server.getServlet().getContextPath(), this.zuulProperties,
proxyRequestHelper);
}
// route filters
@Bean
@ConditionalOnMissingBean(RibbonRoutingFilter.class)
public RibbonRoutingFilter ribbonRoutingFilter(ProxyRequestHelper helper,
RibbonCommandFactory<?> ribbonCommandFactory) {
RibbonRoutingFilter filter = new RibbonRoutingFilter(helper, ribbonCommandFactory,
this.requestCustomizers);
return filter;
}
@Bean
@ConditionalOnMissingBean({ SimpleHostRoutingFilter.class,
CloseableHttpClient.class })
public SimpleHostRoutingFilter simpleHostRoutingFilter(ProxyRequestHelper helper,
ZuulProperties zuulProperties,
ApacheHttpClientConnectionManagerFactory connectionManagerFactory,
ApacheHttpClientFactory httpClientFactory) {
return new SimpleHostRoutingFilter(helper, zuulProperties,
connectionManagerFactory, httpClientFactory);
}
@Bean
@ConditionalOnMissingBean({ SimpleHostRoutingFilter.class })
public SimpleHostRoutingFilter simpleHostRoutingFilter2(ProxyRequestHelper helper,
ZuulProperties zuulProperties, CloseableHttpClient httpClient) {
return new SimpleHostRoutingFilter(helper, zuulProperties, httpClient);
}
@Bean
@ConditionalOnMissingBean(ServiceRouteMapper.class)
public ServiceRouteMapper serviceRouteMapper() {
return new SimpleServiceRouteMapper();
}
@Configuration(proxyBeanMethods = false)
@ConditionalOnMissingClass("org.springframework.boot.actuate.health.Health")
protected static class NoActuatorConfiguration {
@Bean
public ProxyRequestHelper proxyRequestHelper(ZuulProperties zuulProperties) {
ProxyRequestHelper helper = new ProxyRequestHelper(zuulProperties);
return helper;
}
}
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(Health.class)
protected static class EndpointConfiguration {
@Autowired(required = false)
private HttpTraceRepository traces;
@Bean
@ConditionalOnAvailableEndpoint
public RoutesEndpoint routesEndpoint(RouteLocator routeLocator) {
return new RoutesEndpoint(routeLocator);
}
@ConditionalOnAvailableEndpoint
@Bean
public FiltersEndpoint filtersEndpoint() {
FilterRegistry filterRegistry = FilterRegistry.instance();
return new FiltersEndpoint(filterRegistry);
}
@Bean
public ProxyRequestHelper proxyRequestHelper(ZuulProperties zuulProperties) {
TraceProxyRequestHelper helper = new TraceProxyRequestHelper(zuulProperties);
if (this.traces != null) {
helper.setTraces(this.traces);
}
return helper;
}
}
}2、核心类ZuulServlet
1）作用
调度不同阶段的filters，处理异常。所有的Request都要经过ZuulServlet的处理。三个核心的方法preRoute(),route(), postRoute()，zuul对request处理逻辑都在这三个方法里。源码如下：
java
public class ZuulServlet extends HttpServlet {
private static final long serialVersionUID = -3374242278843351500L;
private ZuulRunner zuulRunner;
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
String bufferReqsStr = config.getInitParameter("buffer-requests");
boolean bufferReqs = bufferReqsStr != null && bufferReqsStr.equals("true") ? true : false;
zuulRunner = new ZuulRunner(bufferReqs);
}
@Override
public void service(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse) throws ServletException, IOException {
try {
init((HttpServletRequest) servletRequest, (HttpServletResponse) servletResponse);
// Marks this request as having passed through the "Zuul engine", as opposed to servlets
// explicitly bound in web.xml, for which requests will not have the same data attached
RequestContext context = RequestContext.getCurrentContext();
context.setZuulEngineRan();
try {
preRoute();
} catch (ZuulException e) {
error(e);
postRoute();
return;
}
try {
route();
} catch (ZuulException e) {
error(e);
postRoute();
return;
}
try {
postRoute();
} catch (ZuulException e) {
error(e);
return;
}
} catch (Throwable e) {
error(new ZuulException(e, 500, "UNHANDLED_EXCEPTION_" + e.getClass().getName()));
} finally {
RequestContext.getCurrentContext().unset();
}
}
/**
* executes "post" ZuulFilters
*
* @throws ZuulException
*/
void postRoute() throws ZuulException {
zuulRunner.postRoute();
}
/**
* executes "route" filters
*
* @throws ZuulException
*/
void route() throws ZuulException {
zuulRunner.route();
}
/**
* executes "pre" filters
*
* @throws ZuulException
*/
void preRoute() throws ZuulException {
zuulRunner.preRoute();
}
/**
* initializes request
*
* @param servletRequest
* @param servletResponse
*/
void init(HttpServletRequest servletRequest, HttpServletResponse servletResponse) {
zuulRunner.init(servletRequest, servletResponse);
}
/**
* sets error context info and executes "error" filters
*
* @param e
*/
void error(ZuulException e) {
RequestContext.getCurrentContext().setThrowable(e);
zuulRunner.error();
}
}2）调用链路：
以preRoute()为例：
1、ZuulServlet------》ZuulRunner，源码见四-2-1）；
2、ZuulRunner------》FilterProcessor，源码如下：
java
public void preRoute() throws ZuulException {
FilterProcessor.getInstance().preRoute();
}3、FilterProcessor调自己的runFilters方法，涉及调用其他类：
FilterProcessor------》FilterLoader，源码见下方4
实际执行过滤器逻辑是在调用自己processZuulFilter方法中的下方的代码逻辑。
ZuulFilterResult result = filter.runFilter();（runFilter里面调用了子类的run方法）
java
public void preRoute() throws ZuulException {
try {
runFilters("pre");
} catch (ZuulException e) {
throw e;
} catch (Throwable e) {
throw new ZuulException(e, 500, "UNCAUGHT_EXCEPTION_IN_PRE_FILTER_" + e.getClass().getName());
}
}
/**
* runs all filters of the filterType sType/ Use this method within filters to run custom filters by type
*
* @param sType the filterType.
* @return
* @throws Throwable throws up an arbitrary exception
*/
public Object runFilters(String sType) throws Throwable {
if (RequestContext.getCurrentContext().debugRouting()) {
Debug.addRoutingDebug("Invoking {" + sType + "} type filters");
}
boolean bResult = false;
List<ZuulFilter> list = FilterLoader.getInstance().getFiltersByType(sType);
if (list != null) {
for (int i = 0; i < list.size(); i++) {
ZuulFilter zuulFilter = list.get(i);
Object result = processZuulFilter(zuulFilter);
if (result != null && result instanceof Boolean) {
bResult |= ((Boolean) result);
}
}
}
return bResult;
}
public Object processZuulFilter(ZuulFilter filter) throws ZuulException {
RequestContext ctx = RequestContext.getCurrentContext();
boolean bDebug = ctx.debugRouting();
final String metricPrefix = "zuul.filter-";
long execTime = 0;
String filterName = "";
try {
long ltime = System.currentTimeMillis();
filterName = filter.getClass().getSimpleName();
RequestContext copy = null;
Object o = null;
Throwable t = null;
if (bDebug) {
Debug.addRoutingDebug("Filter " + filter.filterType() + " " + filter.filterOrder() + " " + filterName);
copy = ctx.copy();
}
ZuulFilterResult result = filter.runFilter();
ExecutionStatus s = result.getStatus();
execTime = System.currentTimeMillis() - ltime;
switch (s) {
case FAILED:
t = result.getException();
ctx.addFilterExecutionSummary(filterName, ExecutionStatus.FAILED.name(), execTime);
break;
case SUCCESS:
o = result.getResult();
ctx.addFilterExecutionSummary(filterName, ExecutionStatus.SUCCESS.name(), execTime);
if (bDebug) {
Debug.addRoutingDebug("Filter {" + filterName + " TYPE:" + filter.filterType() + " ORDER:" + filter.filterOrder() + "} Execution time = " + execTime + "ms");
Debug.compareContextState(filterName, copy);
}
break;
default:
break;
}
if (t != null) throw t;
usageNotifier.notify(filter, s);
return o;
} catch (Throwable e) {
if (bDebug) {
Debug.addRoutingDebug("Running Filter failed " + filterName + " type:" + filter.filterType() + " order:" + filter.filterOrder() + " " + e.getMessage());
}
usageNotifier.notify(filter, ExecutionStatus.FAILED);
if (e instanceof ZuulException) {
throw (ZuulException) e;
} else {
ZuulException ex = new ZuulException(e, "Filter threw Exception", 500, filter.filterType() + ":" + filterName);
ctx.addFilterExecutionSummary(filterName, ExecutionStatus.FAILED.name(), execTime);
throw ex;
}
}
}4、FilterLoader------》filterRegistry，通过filterRegistry拿到所有的过滤器并筛选返回符合要求类型的集合并按优先级排序，放入缓存。
java
/**
* Returns a list of filters by the filterType specified
*
* @param filterType
* @return a List<ZuulFilter>
*/
public List<ZuulFilter> getFiltersByType(String filterType) {
List<ZuulFilter> list = hashFiltersByType.get(filterType);
if (list != null) return list;
list = new ArrayList<ZuulFilter>();
Collection<ZuulFilter> filters = filterRegistry.getAllFilters();
for (Iterator<ZuulFilter> iterator = filters.iterator(); iterator.hasNext(); ) {
ZuulFilter filter = iterator.next();
if (filter.filterType().equals(filterType)) {
list.add(filter);
}
}
Collections.sort(list); // sort by priority
hashFiltersByType.putIfAbsent(filterType, list);
return list;
}5、FilterRegistry调用自己的getAllFilters方法返回所有的过滤器
java
private final ConcurrentHashMap<String, ZuulFilter> filters = new ConcurrentHashMap<String, ZuulFilter>();
public Collection<ZuulFilter> getAllFilters() {
return this.filters.values();
}3、顶级抽象父类ZuulFilter
所有的过滤器都应继承该抽象类，重写shouldFilter、filterType、filterOrder、run方法。
shouldFilter：该过滤器是否生效 返回true:有效；false：无效
filterType：指定过滤器类型，FilterConstants包含下面图中几种类型：
filterOrder：在过滤器链中的顺序，返回值越小越靠前；
run：过滤器的逻辑。
java
public abstract class ZuulFilter implements IZuulFilter, Comparable<ZuulFilter> {
abstract boolean shouldFilter();
abstract Object run() throws ZuulException;
abstract public String filterType();
/**
* filterOrder() must also be defined for a filter. Filters may have the same filterOrder if precedence is not
* important for a filter. filterOrders do not need to be sequential.
*
* @return the int order of a filter
*/
abstract public int filterOrder();
public int compareTo(ZuulFilter filter) {
return Integer.compare(this.filterOrder(), filter.filterOrder());
}
}4、过滤器热加载
参考下方博客：