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在spring cloud gateway 为 2.x 的版本的时候，可以通过引入 ribbon ，在进行过滤器 LoadBalancerClientFilter 进行服务请求路由时，通过调用 choose 方法选择具体的服务实例，源码如下：
public class LoadBalancerClientFilter implements GlobalFilter, Ordered { public static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10100; private static final Log log = LogFactory.getLog(LoadBalancerClientFilter.class); protected final LoadBalancerClient loadBalancer; private LoadBalancerProperties properties; public LoadBalancerClientFilter(LoadBalancerClient loadBalancer, LoadBalancerProperties properties) { this.loadBalancer = loadBalancer; this.properties = properties; } public int getOrder() { return 10100; } public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { URI url = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR); String schemePrefix = (String)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR); if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) { ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url); if (log.isTraceEnabled()) { log.trace("LoadBalancerClientFilter url before: " + url); } ServiceInstance instance = this.choose(exchange); if (instance == null) { throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost()); } else { URI uri = exchange.getRequest().getURI(); String overrideScheme = instance.isSecure() ? "https" : "http"; if (schemePrefix != null) { overrideScheme = url.getScheme(); } URI requestUrl = this.loadBalancer.reconstructURI(new DelegatingServiceInstance(instance, overrideScheme), uri); if (log.isTraceEnabled()) { log.trace("LoadBalancerClientFilter url chosen: " + requestUrl); } exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl); return chain.filter(exchange); } } else { return chain.filter(exchange); } } protected ServiceInstance choose(ServerWebExchange exchange) { return this.loadBalancer.choose(((URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR)).getHost()); } }
在choose 方法的调用中，打断点跟进，如果服务中引入了 ribbon ，断点会进入 到 RibbonLoadBalancerClient 中
在使用 ribbon 的过程中，服务的实例是在 RibbonLoadBalancerClient.RibbonServer 类中进行了实例的封装，源码如下：
public static class RibbonServer implements ServiceInstance { private final String serviceId; private final Server server; private final boolean secure; private Map<String, String> metadata; public RibbonServer(String serviceId, Server server) { this(serviceId, server, false, Collections.emptyMap()); } public RibbonServer(String serviceId, Server server, boolean secure, Map<String, String> metadata) { this.serviceId = serviceId; this.server = server; this.secure = secure; this.metadata = metadata; } public String getInstanceId() { return this.server.getId(); } public String getServiceId() { return this.serviceId; } public String getHost() { return this.server.getHost(); } public int getPort() { return this.server.getPort(); } public boolean isSecure() { return this.secure; } public URI getUri() { return DefaultServiceInstance.getUri(this); } public Map<String, String> getMetadata() { return this.metadata; } public Server getServer() { return this.server; } public String getScheme() { return this.server.getScheme(); } public String toString() { StringBuilder sb = new StringBuilder("RibbonServer{"); sb.append("serviceId='").append(this.serviceId).append('\''); sb.append(", server=").append(this.server); sb.append(", secure=").append(this.secure); sb.append(", metadata=").append(this.metadata); sb.append('}'); return sb.toString(); } }
在 服务路由进行请求时，会根据其中的 isSecure 属性判断是否进行 https 请求，如果是 isSecure 是 true，则请求的scheme 协议为 https，反之为 http ；该值可以通过以下方式进行配置：
ribbon.isSecure=true
在 spring cloud gateway 中spring-cloud--openfeign-core为 3.x 的版本的时候，该依赖中 将 ribbon 单独的脱离了出来，此时的ribbon 配置不会生效。通过阅读源码之后会发现，该请求的协议是通过调用服务的 sslPort端口来判断是否进行https 请求，如果 sslPort端口不为空，则进行https 请求,
以使用 zookeeper 为注册中心时，查看自动发现配置的property 文件：
@ConfigurationProperties("spring.cloud.zookeeper.discovery") public class ZookeeperDiscoveryProperties { public static final String DEFAULT_URI_SPEC = "{scheme}://{address}:{port}"; private HostInfo hostInfo; private boolean enabled = true; private String root = "/services"; private String uriSpec = "{scheme}://{address}:{port}"; private String instanceId; private String instanceHost; private String instanceIpAddress; private boolean preferIpAddress = false; private Integer instancePort; private Integer instanceSslPort; private boolean register = true; private Map<String, String> metadata = new HashMap(); private String initialStatus = "UP"; private int order = 0; }
在 choose 选择路由的服务时，会 根据ServiceInstance的实例的 isSecure 属性，解析得出http 或https，而zookeeperInstance 是根据 instanceSslPort 端口是否为空进行解析出http或https。zookeeperInstance解析http与https的源码在ZookeeperServiceInstance中
如果想在服务路由时，进行https 的路由，可以进行如下的配置：
server: port: 9000 spring: application: name: my-zookeeper-registry cloud: zookeeper: connect-string: localhost:2181 discovery: register: true enabled: true root: my-registry instance-ssl-port: {{server.port}}
按照上述配置，可以实现 https 的网关路由转发。
标签: spring cloud
