- 背景 -
最近在github上看了soul网关的设计，突然就来了兴趣准备自己从零开始写一个高性能的网关。经过两周时间的开发，我的网关ship-gate核心功能基本都已完成，最大的缺陷就是前端功底太差没有管理后台。
- 设计 -
1、技术选型
网关是所有请求的入口，所以要求有很高的吞吐量，为了实现这点可以使用请求异步化来解决。目前一般有以下两种方案：- Tomcat/Jetty+NIO+Servlet3
Servlet3已经支持异步，这种方案使用比较多，京东，有赞和Zuul，都用的是这种方案。Netty为高并发而生，目前唯品会的网关使用这个策略，在唯品会的技术文章中在相同的情况下Netty是每秒30w+的吞吐量，Tomcat是13w+,可以看出是有一定的差距的，但是Netty需要自己处理HTTP协议，这一块比较麻烦。后面发现Soul网关是基于Spring WebFlux（底层Netty）的，不用太关心HTTP协议的处理，于是决定也用Spring WebFlux。网关的第二个特点是具备可扩展性，比如Netflix Zuul有preFilters，postFilters等在不同的阶段方便处理不同的业务，基于责任链模式将请求进行链式处理即可实现。在微服务架构下，服务都会进行多实例部署来保证高可用，请求到达网关时，网关需要根据URL找到所有可用的实例，这时就需要服务注册和发现功能，即注册中心。现在流行的注册中心有Apache的Zookeeper和阿里的Nacos两种（consul有点小众），因为之前写RPC框架时已经用过了Zookeeper，所以这次就选择了Nacos。2、需求清单
首先要明确目标，即开发一个具备哪些特性的网关，总结下后如下：可基于version的路由规则设置，路由对象包括DEFAUL,HEADER和QUERY三种，匹配方式包括=、regex、like三种。Netty本身就是一款高性能的通信框架，同时server将一些路由规则等数据缓存到JVM内存避免请求admin服务。灰度发布（又名金丝雀发布）是指在黑与白之间，能够平滑过渡的一种发布方式。在其上可以进行A/B testing，即让一部分用户继续用产品特性A，一部分用户开始用产品特性B，如果用户对B没有什么反对意见，那么逐步扩大范围，把所有用户都迁移到B上面来。通过特性一可以实现。支持多种负载均衡算法，如随机，轮询，加权轮询等。利用SPI机制可以根据配置进行动态加载。3、架构设计
在参考了一些优秀的网关Zuul,Spring Cloud Gateway,Soul后，将项目划分为以下几个模块。注意： 这张图与实际实现有点出入，Nacos push到本地缓存的那个环节没有实现，目前只有ship-sever定时轮询pull的过程。ship-admin从Nacos获取注册服务信息的过程，也改成了ServiceA启动时主动发生HTTP请求通知ship-admin。4、表结构设计
- 编码 -
1、ship-client-spring-boot-starter首先创建一个spring-boot-starter命名为ship-client-spring-boot-starter，不知道如何自定义starter的可以看我以前写的《开发自己的starter》。其核心类 AutoRegisterListener 就是在项目启动时做了两件事：2.通知ship-admin服务上线了并注册下线hook。* Created by 2YSP on 2020/12/21
*/
public class AutoRegisterListener implements ApplicationListener<ContextRefreshedEvent> {
private final static Logger LOGGER = LoggerFactory.getLogger(AutoRegisterListener.class);
private volatile AtomicBoolean registered = new AtomicBoolean(false);
private final ClientConfigProperties properties;
@NacosInjected
private NamingService namingService;
@Autowired
private RequestMappingHandlerMapping handlerMapping;
private final ExecutorService pool;
/**
* url list to ignore
*/
private static List ignoreUrlList = new LinkedList<>();
static {
ignoreUrlList.add("/error");
}
public AutoRegisterListener(ClientConfigProperties properties) {
if (!check(properties)) {
LOGGER.error("client config port,contextPath,appName adminUrl and version can't be empty!");
throw new ShipException("client config port,contextPath,appName adminUrl and version can't be empty!");
}
this.properties = properties;
pool = new ThreadPoolExecutor(1, 4, 0, TimeUnit.SECONDS, new LinkedBlockingQueue<>());
}
/**
* check the ClientConfigProperties
*
* @param properties
* @return
*/
private boolean check(ClientConfigProperties properties) {
if (properties.getPort() == null| properties.getContextPath() == null
| properties.getVersion() == null| properties.getAppName() == null
| properties.getAdminUrl() == null) {
return false;
}
return true;
}
@Override
public void onApplicationEvent(ContextRefreshedEvent event) {
if (!registered.compareAndSet(false, true)) {
return;
}
doRegister();
registerShutDownHook();
}
/**
* send unregister request to admin when jvm shutdown
*/
private void registerShutDownHook() {
final String url = "http://" + properties.getAdminUrl() + AdminConstants.UNREGISTER_PATH;
final UnregisterAppDTO unregisterAppDTO = new UnregisterAppDTO();
unregisterAppDTO.setAppName(properties.getAppName());
unregisterAppDTO.setVersion(properties.getVersion());
unregisterAppDTO.setIp(IpUtil.getLocalIpAddress());
unregisterAppDTO.setPort(properties.getPort());
Runtime.getRuntime().addShutdownHook(new Thread(() -> {
OkhttpTool.doPost(url, unregisterAppDTO);
LOGGER.info("[{}:{}] unregister from ship-admin success!", unregisterAppDTO.getAppName(), unregisterAppDTO.getVersion());
}));
}
/**
* register all interface info to register center
*/
private void doRegister() {
Instance instance = new Instance();
instance.setIp(IpUtil.getLocalIpAddress());
instance.setPort(properties.getPort());
instance.setEphemeral(true);
Map metadataMap = new HashMap<>();
metadataMap.put("version", properties.getVersion());
metadataMap.put("appName", properties.getAppName());
instance.setMetadata(metadataMap);
try {
namingService.registerInstance(properties.getAppName(), NacosConstants.APP_GROUP_NAME, instance);
} catch (NacosException e) {
LOGGER.error("register to nacos fail", e);
throw new ShipException(e.getErrCode(), e.getErrMsg());
}
LOGGER.info("register interface info to nacos success!");
// send register request to ship-admin
String url = "http://" + properties.getAdminUrl() + AdminConstants.REGISTER_PATH;
RegisterAppDTO registerAppDTO = buildRegisterAppDTO(instance);
OkhttpTool.doPost(url, registerAppDTO);
LOGGER.info("register to ship-admin success!");
}
private RegisterAppDTO buildRegisterAppDTO(Instance instance) {
RegisterAppDTO registerAppDTO = new RegisterAppDTO();
registerAppDTO.setAppName(properties.getAppName());
registerAppDTO.setContextPath(properties.getContextPath());
registerAppDTO.setIp(instance.getIp());
registerAppDTO.setPort(instance.getPort());
registerAppDTO.setVersion(properties.getVersion());
return registerAppDTO;
}
}
ship-sever项目主要包括了两个部分内容， 1.请求动态路由的主流程 2.本地缓存数据和ship-admin及nacos同步，这部分在后面3.3再讲。ship-server实现动态路由的原理是利用WebFilter拦截请求，然后将请求教给plugin chain去链式处理。PluginFilter根据URL解析出appName，然后将启用的plugin组装成plugin chain。public class PluginFilter implements WebFilter {
private ServerConfigProperties properties;
public PluginFilter(ServerConfigProperties properties) {
this.properties = properties;
}
@Override
public Mono filter(ServerWebExchange exchange, WebFilterChain chain) {
String appName = parseAppName(exchange);
if (CollectionUtils.isEmpty(ServiceCache.getAllInstances(appName))) {
throw new ShipException(ShipExceptionEnum.SERVICE_NOT_FIND);
}
PluginChain pluginChain = new PluginChain(properties, appName);
pluginChain.addPlugin(new DynamicRoutePlugin(properties));
pluginChain.addPlugin(new AuthPlugin(properties));
return pluginChain.execute(exchange, pluginChain);
}
private String parseAppName(ServerWebExchange exchange) {
RequestPath path = exchange.getRequest().getPath();
String appName = path.value().split("/")[1];
return appName;
}
}```
PluginChain继承了AbstractShipPlugin并持有所有要执行的插件。
```java
* @Author: Ship
* @Description:
* @Date: Created in 2020/12/25
*/
public class PluginChain extends AbstractShipPlugin {
/**
* the pos point to current plugin
*/
private int pos;
/**
* the plugins of chain
*/
private List plugins;
private final String appName;
public PluginChain(ServerConfigProperties properties, String appName) {
super(properties);
this.appName = appName;
}
/**
* add enabled plugin to chain
*
* @param shipPlugin
*/
public void addPlugin(ShipPlugin shipPlugin) {
if (plugins == null) {
plugins = new ArrayList<>();
}
if (!PluginCache.isEnabled(appName, shipPlugin.name())) {
return;
}
plugins.add(shipPlugin);
// order by the plugin's order
plugins.sort(Comparator.comparing(ShipPlugin::order));
}
@Override
public Integer order() {
return null;
}
@Override
public String name() {
return null;
}
@Override
public Mono execute(ServerWebExchange exchange, PluginChain pluginChain) {
if (pos == plugins.size()) {
return exchange.getResponse().setComplete();
}
return pluginChain.plugins.get(pos++).execute(exchange, pluginChain);
}
public String getAppName() {
return appName;
}
}
AbstractShipPlugin实现了ShipPlugin接口，并持有ServerConfigProperties配置对象。
public abstract class AbstractShipPlugin implements ShipPlugin {
protected ServerConfigProperties properties;
public AbstractShipPlugin(ServerConfigProperties properties) {
this.properties = properties;
}
}```
ShipPlugin接口定义了所有插件必须实现的三个方法order(),name()和execute()。
```java
public interface ShipPlugin {
/**
* lower values have higher priority
*
* @return
*/
Integer order();
/**
* return current plugin name
*
* @return
*/
String name();
Mono execute(ServerWebExchange exchange,PluginChain pluginChain);
}```
DynamicRoutePlugin继承了抽象类AbstractShipPlugin，包含了动态路由的主要业务逻辑。
```java
* @Author: Ship
* @Description:
* @Date: Created in 2020/12/25
*/
public class DynamicRoutePlugin extends AbstractShipPlugin {
private final static Logger LOGGER = LoggerFactory.getLogger(DynamicRoutePlugin.class);
private static WebClient webClient;
private static final Gson gson = new GsonBuilder().create();
static {
HttpClient httpClient = HttpClient.create()
.tcpConfiguration(client ->
client.doOnConnected(conn ->
conn.addHandlerLast(new ReadTimeoutHandler(3))
.addHandlerLast(new WriteTimeoutHandler(3)))
.option(ChannelOption.TCP_NODELAY, true)
);
webClient = WebClient.builder().clientConnector(new ReactorClientHttpConnector(httpClient))
.build();
}
public DynamicRoutePlugin(ServerConfigProperties properties) {
super(properties);
}
@Override
public Integer order() {
return ShipPluginEnum.DYNAMIC_ROUTE.getOrder();
}
@Override
public String name() {
return ShipPluginEnum.DYNAMIC_ROUTE.getName();
}
@Override
public Mono execute(ServerWebExchange exchange, PluginChain pluginChain) {
String appName = pluginChain.getAppName();
ServiceInstance serviceInstance = chooseInstance(appName, exchange.getRequest());
// LOGGER.info("selected instance is [{}]", gson.toJson(serviceInstance));
// request service
String url = buildUrl(exchange, serviceInstance);
return forward(exchange, url);
}
/**
* forward request to backend service
*
* @param exchange
* @param url
* @return
*/
private Mono forward(ServerWebExchange exchange, String url) {
ServerHttpRequest request = exchange.getRequest();
ServerHttpResponse response = exchange.getResponse();
HttpMethod method = request.getMethod();
WebClient.RequestBodySpec requestBodySpec = webClient.method(method).uri(url).headers((headers) -> {
headers.addAll(request.getHeaders());
});
WebClient.RequestHeadersSpec> reqHeadersSpec;
if (requireHttpBody(method)) {
reqHeadersSpec = requestBodySpec.body(BodyInserters.fromDataBuffers(request.getBody()));
} else {
reqHeadersSpec = requestBodySpec;
}
// nio->callback->nio
return reqHeadersSpec.exchange().timeout(Duration.ofMillis(properties.getTimeOutMillis()))
.onErrorResume(ex -> {
return Mono.defer(() -> {
String errorResultJson = "";
if (ex instanceof TimeoutException) {
errorResultJson = "{\"code\":5001,\"message\":\"network timeout\"}";
} else {
errorResultJson = "{\"code\":5000,\"message\":\"system error\"}";
}
return ShipResponseUtil.doResponse(exchange, errorResultJson);
}).then(Mono.empty());
}).flatMap(backendResponse -> {
response.setStatusCode(backendResponse.statusCode());
response.getHeaders().putAll(backendResponse.headers().asHttpHeaders());
return response.writeWith(backendResponse.bodyToFlux(DataBuffer.class));
});
}
/**
* weather the http method need http body
*
* @param method
* @return
*/
private boolean requireHttpBody(HttpMethod method) {
if (method.equals(HttpMethod.POST)| method.equals(HttpMethod.PUT)| method.equals(HttpMethod.PATCH)) {
return true;
}
return false;
}
private String buildUrl(ServerWebExchange exchange, ServiceInstance serviceInstance) {
ServerHttpRequest request = exchange.getRequest();
String query = request.getURI().getQuery();
String path = request.getPath().value().replaceFirst("/" + serviceInstance.getAppName(), "");
String url = "http://" + serviceInstance.getIp() + ":" + serviceInstance.getPort() + path;
if (!StringUtils.isEmpty(query)) {
url = url + "?" + query;
}
return url;
}
/**
* choose an ServiceInstance according to route rule config and load balancing algorithm
*
* @param appName
* @param request
* @return
*/
private ServiceInstance chooseInstance(String appName, ServerHttpRequest request) {
List serviceInstances = ServiceCache.getAllInstances(appName);
if (CollectionUtils.isEmpty(serviceInstances)) {
LOGGER.error("service instance of {} not find", appName);
throw new ShipException(ShipExceptionEnum.SERVICE_NOT_FIND);
}
String version = matchAppVersion(appName, request);
if (StringUtils.isEmpty(version)) {
throw new ShipException("match app version error");
}
// filter serviceInstances by version
List instances = serviceInstances.stream().filter(i -> i.getVersion().equals(version)).collect(Collectors.toList());
//Select an instance based on the load balancing algorithm
LoadBalance loadBalance = LoadBalanceFactory.getInstance(properties.getLoadBalance(), appName, version);
ServiceInstance serviceInstance = loadBalance.chooseOne(instances);
return serviceInstance;
}
private String matchAppVersion(String appName, ServerHttpRequest request) {
List rules = RouteRuleCache.getRules(appName);
rules.sort(Comparator.comparing(AppRuleDTO::getPriority).reversed());
for (AppRuleDTO rule : rules) {
if (match(rule, request)) {
return rule.getVersion();
}
}
return null;
}
private boolean match(AppRuleDTO rule, ServerHttpRequest request) {
String matchObject = rule.getMatchObject();
String matchKey = rule.getMatchKey();
String matchRule = rule.getMatchRule();
Byte matchMethod = rule.getMatchMethod();
if (MatchObjectEnum.DEFAULT.getCode().equals(matchObject)) {
return true;
} else if (MatchObjectEnum.QUERY.getCode().equals(matchObject)) {
String param = request.getQueryParams().getFirst(matchKey);
if (!StringUtils.isEmpty(param)) {
return StringTools.match(param, matchMethod, matchRule);
}
} else if (MatchObjectEnum.HEADER.getCode().equals(matchObject)) {
HttpHeaders headers = request.getHeaders();
String headerValue = headers.getFirst(matchKey);
if (!StringUtils.isEmpty(headerValue)) {
return StringTools.match(headerValue, matchMethod, matchRule);
}
}
return false;
}
}
3、数据同步
后台服务（如订单服务）启动时，只将服务名，版本，ip地址和端口号注册到了Nacos，并没有实例的权重和启用的插件信息怎么办？一般在线的实例权重和插件列表都是在管理界面配置，然后动态生效的，所以需要ship-admin定时更新实例的权重和插件信息到注册中心。对应代码ship-admin的NacosSyncListener：* @Author: Ship
* @Description:
* @Date: Created in 2020/12/30
*/
@Configuration
public class NacosSyncListener implements ApplicationListener<ContextRefreshedEvent> {
private static final Logger LOGGER = LoggerFactory.getLogger(NacosSyncListener.class);
private static ScheduledThreadPoolExecutor scheduledPool = new ScheduledThreadPoolExecutor(1,
new ShipThreadFactory("nacos-sync", true).create());
@NacosInjected
private NamingService namingService;
@Value("${nacos.discovery.server-addr}")
private String baseUrl;
@Resource
private AppService appService;
@Override
public void onApplicationEvent(ContextRefreshedEvent event) {
if (event.getApplicationContext().getParent() != null) {
return;
}
String url = "http://" + baseUrl + NacosConstants.INSTANCE_UPDATE_PATH;
scheduledPool.scheduleWithFixedDelay(new NacosSyncTask(namingService, url, appService), 0, 30L, TimeUnit.SECONDS);
}
class NacosSyncTask implements Runnable {
private NamingService namingService;
private String url;
private AppService appService;
private Gson gson = new GsonBuilder().create();
public NacosSyncTask(NamingService namingService, String url, AppService appService) {
this.namingService = namingService;
this.url = url;
this.appService = appService;
}
/**
* Regular update weight,enabled plugins to nacos instance
*/
@Override
public void run() {
try {
// get all app names
ListView services = namingService.getServicesOfServer(1, Integer.MAX_VALUE, NacosConstants.APP_GROUP_NAME);
if (CollectionUtils.isEmpty(services.getData())) {
return;
}
List appNames = services.getData();
List appInfos = appService.getAppInfos(appNames);
for (AppInfoDTO appInfo : appInfos) {
if (CollectionUtils.isEmpty(appInfo.getInstances())) {
continue;
}
for (ServiceInstance instance : appInfo.getInstances()) {
Map queryMap = buildQueryMap(appInfo, instance);
String resp = OkhttpTool.doPut(url, queryMap, "");
LOGGER.debug("response :{}", resp);
}
}
} catch (Exception e) {
LOGGER.error("nacos sync task error", e);
}
}
private Map buildQueryMap(AppInfoDTO appInfo, ServiceInstance instance) {
Map map = new HashMap<>();
map.put("serviceName", appInfo.getAppName());
map.put("groupName", NacosConstants.APP_GROUP_NAME);
map.put("ip", instance.getIp());
map.put("port", instance.getPort());
map.put("weight", instance.getWeight().doubleValue());
NacosMetadata metadata = new NacosMetadata();
metadata.setAppName(appInfo.getAppName());
metadata.setVersion(instance.getVersion());
metadata.setPlugins(String.join(",", appInfo.getEnabledPlugins()));
map.put("metadata", StringTools.urlEncode(gson.toJson(metadata)));
map.put("ephemeral", true);
return map;
}
}
}
ship-server再定时从Nacos拉取app数据更新到本地Map缓存。
* @Author: Ship
* @Description: sync data to local cache
* @Date: Created in 2020/12/25
*/
@Configuration
public class DataSyncTaskListener implements ApplicationListener<ContextRefreshedEvent> {
private static ScheduledThreadPoolExecutor scheduledPool = new ScheduledThreadPoolExecutor(1,
new ShipThreadFactory("service-sync", true).create());
@NacosInjected
private NamingService namingService;
@Autowired
private ServerConfigProperties properties;
@Override
public void onApplicationEvent(ContextRefreshedEvent event) {
if (event.getApplicationContext().getParent() != null) {
return;
}
scheduledPool.scheduleWithFixedDelay(new DataSyncTask(namingService)
, 0L, properties.getCacheRefreshInterval(), TimeUnit.SECONDS);
WebsocketSyncCacheServer websocketSyncCacheServer = new WebsocketSyncCacheServer(properties.getWebSocketPort());
websocketSyncCacheServer.start();
}
class DataSyncTask implements Runnable {
private NamingService namingService;
public DataSyncTask(NamingService namingService) {
this.namingService = namingService;
}
@Override
public void run() {
try {
// get all app names
ListView services = namingService.getServicesOfServer(1, Integer.MAX_VALUE, NacosConstants.APP_GROUP_NAME);
if (CollectionUtils.isEmpty(services.getData())) {
return;
}
List appNames = services.getData();
// get all instances
for (String appName : appNames) {
List instanceList = namingService.getAllInstances(appName, NacosConstants.APP_GROUP_NAME);
if (CollectionUtils.isEmpty(instanceList)) {
continue;
}
ServiceCache.add(appName, buildServiceInstances(instanceList));
List pluginNames = getEnabledPlugins(instanceList);
PluginCache.add(appName, pluginNames);
}
ServiceCache.removeExpired(appNames);
PluginCache.removeExpired(appNames);
} catch (NacosException e) {
e.printStackTrace();
}
}
private List getEnabledPlugins(List instanceList) {
Instance instance = instanceList.get(0);
Map metadata = instance.getMetadata();
// plugins: DynamicRoute,Auth
String plugins = metadata.getOrDefault("plugins", ShipPluginEnum.DYNAMIC_ROUTE.getName());
return Arrays.stream(plugins.split(",")).collect(Collectors.toList());
}
private List buildServiceInstances(List instanceList) {
List list = new LinkedList<>();
instanceList.forEach(instance -> {
Map metadata = instance.getMetadata();
ServiceInstance serviceInstance = new ServiceInstance();
serviceInstance.setAppName(metadata.get("appName"));
serviceInstance.setIp(instance.getIp());
serviceInstance.setPort(instance.getPort());
serviceInstance.setVersion(metadata.get("version"));
serviceInstance.setWeight((int) instance.getWeight());
list.add(serviceInstance);
});
return list;
}
}
}
路由规则数据同步
同时，如果用户在管理后台更新了路由规则，ship-admin需要推送规则数据到ship-server，这里参考了soul网关的做法利用websocket在第一次建立连接后进行全量同步，此后路由规则发生变更就只作增量同步。服务端WebsocketSyncCacheServer：* @Author: Ship
* @Description:
* @Date: Created in 2020/12/28
*/
public class WebsocketSyncCacheServer extends WebSocketServer {
private final static Logger LOGGER = LoggerFactory.getLogger(WebsocketSyncCacheServer.class);
private Gson gson = new GsonBuilder().create();
private MessageHandler messageHandler;
public WebsocketSyncCacheServer(Integer port) {
super(new InetSocketAddress(port));
this.messageHandler = new
