spring cloud gateway 和 Ribbon的整合

2020-12-09 本文已影响0人惠惠雨辰

在spring cloud gateway的源码中，我们看到会调用 RibbonLoadBalancerClient.choose(String serviceId)的方法。这个方法调用了getServer（serviceId），choose方法就是通过Ribbon获取到服务的ip。

public ServiceInstance choose(String serviceId) {

Server server = getServer(serviceId);

if (server ==null) {

return null;

}

return new RibbonServer(serviceId, server, isSecure(server, serviceId),

serverIntrospector(serviceId).getMetadata(server));

}

1.getServer(serviceId)方法这个方法调用了getLoadBalancer(serviceId)，getLoadBalancer（serviceId）这个方法就是通过工厂来获取LoadBanlancer。

protected Server getServer(String serviceId) {

return getServer(getLoadBalancer(serviceId));

}

protected Server getServer(ILoadBalancer loadBalancer) {

if (loadBalancer ==null) {

return null;

}

return loadBalancer.chooseServer("default");// TODO: better handling of key

}

protected ILoadBalancer getLoadBalancer(String serviceId) {

return this.clientFactory.getLoadBalancer(serviceId);

}

获取到服务的ip后，gateway获取到url，并且组装成调用下游的绝对路径，进行调用

URI uri = exchange.getRequest().getURI();

// if the `lb:` mechanism was used, use `` as the default,

// if the loadbalancer doesn't provide one.

String overrideScheme =null;

if (schemePrefix !=null) {

overrideScheme = url.getScheme();

}

URI requestUrl =loadBalancer.reconstructURI(new DelegatingServiceInstance(instance, overrideScheme), uri);

最后将具体的uri放到exchange上下文的GATEWAY_REQUEST_URL_ATTR中