一、前言

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。

二、设计

2.1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+NIO

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。

2.2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：

自定义路由规则可基于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。
跨语言HTTP协议天生跨语言
高性能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。
高可用支持集群模式防止单节点故障，无状态。
灰度发布灰度发布（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。
接口鉴权基于责任链模式，用户开发自己的鉴权插件即可。
负载均衡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。

2.3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。

它们之间的关系如图：

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。

2.4表结构设计

三、编码

3.1 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：

1.将服务信息注册到Nacos注册中心

2.通知ship-admin服务上线了并注册下线hook。

代码如下：

/** * 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<String> 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<String, String> 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;    }}

3.2 ship-server

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，然后将请求交给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<Void> 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。

/** * @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<ShipPlugin> 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<Void> 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()。

public interface ShipPlugin {    /**     * lower values have higher priority     *     * @return     */    Integer order();     /**     * return current plugin name     *     * @return     */    String name();     Mono<Void> 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。

/** * @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<Void> 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<Void> 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<ServiceInstance> 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<ServiceInstance> 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<AppRuleDTO> 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;    } }

3.3 数据同步

app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 */@Configurationpublic 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<String> services = namingService.getServicesOfServer(1, Integer.MAX_VALUE, NacosConstants.APP_GROUP_NAME);                if (CollectionUtils.isEmpty(services.getData())) {                    return;                }                List<String> appNames = services.getData();                List<AppInfoDTO> appInfos = appService.getAppInfos(appNames);                for (AppInfoDTO appInfo : appInfos) {                    if (CollectionUtils.isEmpty(appInfo.getInstances())) {                        continue;                    }                    for (ServiceInstance instance : appInfo.getInstances()) {                        Map<String, Object> 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<String, Object> buildQueryMap(AppInfoDTO appInfo, ServiceInstance instance) {            Map<String, Object> 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 */@Configurationpublic 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<String> services = namingService.getServicesOfServer(1, Integer.MAX_VALUE, NacosConstants.APP_GROUP_NAME);                if (CollectionUtils.isEmpty(services.getData())) {                    return;                }                List<String> appNames = services.getData();                // get all instances                for (String appName : appNames) {                    List<Instance> instanceList = namingService.getAllInstances(appName, NacosConstants.APP_GROUP_NAME);                    if (CollectionUtils.isEmpty(instanceList)) {                        continue;                    }                    ServiceCache.add(appName, buildServiceInstances(instanceList));                    List<String> pluginNames = getEnabledPlugins(instanceList);                    PluginCache.add(appName, pluginNames);                }                ServiceCache.removeExpired(appNames);                PluginCache.removeExpired(appNames);             } catch (NacosException e) {                e.printStackTrace();            }        }         private List<String> getEnabledPlugins(List<Instance> instanceList) {            Instance instance = instanceList.get(0);            Map<String, String> 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<ServiceInstance> buildServiceInstances(List<Instance> instanceList) {            List<ServiceInstance> list = new LinkedList<>();            instanceList.forEach(instance -> {                Map<String, String> 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 MessageHandler();    }      @Override    public void onOpen(WebSocket webSocket, ClientHandshake clientHandshake) {        LOGGER.info("server is open");    }     @Override    public void onClose(WebSocket webSocket, int i, String s, boolean b) {        LOGGER.info("websocket server close...");    }     @Override    public void onMessage(WebSocket webSocket, String message) {        LOGGER.info("websocket server receive message:\n[{}]", message);        this.messageHandler.handler(message);    }     @Override    public void onError(WebSocket webSocket, Exception e) {     }     @Override    public void onStart() {        LOGGER.info("websocket server start...");    }      class MessageHandler {         public void handler(String message) {            RouteRuleOperationDTO operationDTO = gson.fromJson(message, RouteRuleOperationDTO.class);            if (CollectionUtils.isEmpty(operationDTO.getRuleList())) {                return;            }            Map<String, List<AppRuleDTO>> map = operationDTO.getRuleList()                    .stream().collect(Collectors.groupingBy(AppRuleDTO::getAppName));            if (OperationTypeEnum.INSERT.getCode().equals(operationDTO.getOperationType())                    || OperationTypeEnum.UPDATE.getCode().equals(operationDTO.getOperationType())) {                RouteRuleCache.add(map);            } else if (OperationTypeEnum.DELETE.getCode().equals(operationDTO.getOperationType())) {                RouteRuleCache.remove(map);            }        }    }}

客户端WebsocketSyncCacheClient：

/** * @Author: Ship * @Description: * @Date: Created in 2020/12/28 */@Componentpublic class WebsocketSyncCacheClient {     private final static Logger LOGGER = LoggerFactory.getLogger(WebsocketSyncCacheClient.class);     private WebSocketClient client;     private RuleService ruleService;     private Gson gson = new GsonBuilder().create();     public WebsocketSyncCacheClient(@Value("${ship.server-web-socket-url}") String serverWebSocketUrl,                                    RuleService ruleService) {        if (StringUtils.isEmpty(serverWebSocketUrl)) {            throw new ShipException(ShipExceptionEnum.CONFIG_ERROR);        }        this.ruleService = ruleService;        ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1,                new ShipThreadFactory("websocket-connect", true).create());        try {            client = new WebSocketClient(new URI(serverWebSocketUrl)) {                @Override                public void onOpen(ServerHandshake serverHandshake) {                    LOGGER.info("client is open");                    List<AppRuleDTO> list = ruleService.getEnabledRule();                    String msg = gson.toJson(new RouteRuleOperationDTO(OperationTypeEnum.INSERT, list));                    send(msg);                }                 @Override                public void onMessage(String s) {                }                 @Override                public void onClose(int i, String s, boolean b) {                }                 @Override                public void onError(Exception e) {                    LOGGER.error("websocket client error", e);                }            };             client.connectBlocking();            //使用调度线程池进行断线重连，30秒进行一次            executor.scheduleAtFixedRate(() -> {                if (client != null && client.isClosed()) {                    try {                        client.reconnectBlocking();                    } catch (InterruptedException e) {                        LOGGER.error("reconnect server fail", e);                    }                }            }, 10, 30, TimeUnit.SECONDS);         } catch (Exception e) {            LOGGER.error("websocket sync cache exception", e);            throw new ShipException(e.getMessage());        }    }     public <T> void send(T t) {        while (!client.getReadyState().equals(ReadyState.OPEN)) {            LOGGER.debug("connecting ...please wait");        }        client.send(gson.toJson(t));    }}

四、测试

4.1动态路由测试

本地启动nacos ,sh startup.sh -m standalone
启动ship-admin
本地启动两个ship-example实例。实例1配置：ship: http: app-name: order version: gray_1.0 context-path: /order port: 8081 admin-url: 127.0.0.1:9001 server: port: 8081 nacos: discovery: server-addr: 127.0.0.1:8848实例2配置：ship: http: app-name: order version: prod_1.0 context-path: /order port: 8082 admin-url: 127.0.0.1:9001 server: port: 8082 nacos: discovery: server-addr: 127.0.0.1:8848
在数据库添加路由规则配置，该规则表示当http header 中的name=ship是请求路由到gray_1.0版本的节点。

启动ship-server,看到以下日志时则可以进行测试了。2021-01-02 19:57:09.159 INFO 30413 --- [SocketWorker-29] cn.sp.sync.WebsocketSyncCacheServer : websocket server receive message:[{"operationType":"INSERT","ruleList":[{"id":1,"appId":5,"appName":"order","version":"gray_1.0","matchObject":"HEADER","matchKey":"name","matchMethod":1,"matchRule":"ship","priority":50}]}]
用Postman请求http://localhost:9000/order/user/add,POST方式，header设置name=ship，可以看到只有实例1有日志显示。==========add user,version:gray_1.0

4.2性能压测

压测环境：

MacBook Pro 13英寸

处理器 2.3 GHz 四核Intel Core i7

内存 16 GB 3733 MHz LPDDR4X

后端节点个数一个

压测工具：wrk

压测结果：20个线程，500个连接数，吞吐量大概每秒9400个请求。

五、总结

千里之行始于足下，开始以为写一个网关会很难，但当你实际开始行动时就会发现其实没那么难，所以迈出第一步很重要。过程中也遇到了很多问题，还在github上给soul和nacos这两个开源项目提了两个issue，后来发现是自己的问题，尴尬。

原文链接：https://www.cnblogs.com/2YSP/p/14223892.html

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如何设计一个高性能网关？