springcloud-ribbon客户端负载均衡

1. 注入了LoadBalanced的restTemplate

@Bean
@LoadBalanced
public RestTemplate restTemplate(){
	return new RestTemplate();
}

2. 使用restTemplate调用API是会被LoadBalancerInterceptor拦截

@Override
public  T execute(String serviceId, LoadBalancerRequest request) throws IOException {
	ILoadBalancer loadBalancer = getLoadBalancer(serviceId);
	Server server = getServer(loadBalancer);
	if (server == null) {
		throw new IllegalStateException("No instances available for " + serviceId);
	}
	RibbonServer ribbonServer = new RibbonServer(serviceId, server, isSecure(server,
			serviceId), serverIntrospector(serviceId).getMetadata(server));

	return execute(serviceId, ribbonServer, request);
}

serviceId：originalUri.getHost();

springboot自动配置RibbonAutoConfiguration，默认RibbonLoadBalancerClient

@Bean
@ConditionalOnMissingBean(LoadBalancerClient.class)
public LoadBalancerClient loadBalancerClient() {
	return new RibbonLoadBalancerClient(springClientFactory());
}

直接上主流程代码

@Override
public  T execute(String serviceId, LoadBalancerRequest request) throws IOException {
	// 获取负载均衡器
	ILoadBalancer loadBalancer = getLoadBalancer(serviceId);
	// 通过负载均衡器，依据相应策略获取服务
	Server server = getServer(loadBalancer);
	if (server == null) {
		throw new IllegalStateException("No instances available for " + serviceId);
	}
	// 封装为ribbonServer
	RibbonServer ribbonServer = new RibbonServer(serviceId, server, isSecure(server,
			serviceId), serverIntrospector(serviceId).getMetadata(server));
	// 执行服务调用
	return execute(serviceId, ribbonServer, request);
}

1. 获取loadBalancer

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// 是如何获取到的？
protected ILoadBalancer getLoadBalancer(String serviceId) {
	return this.clientFactory.getLoadBalancer(serviceId);
}

2. 获取server

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springboot自动配置RibbonAutoConfiguration，默认RibbonLoadBalancerClient

@Bean
@ConditionalOnMissingBean(LoadBalancerClient.class)
public LoadBalancerClient loadBalancerClient() {
	return new RibbonLoadBalancerClient(springClientFactory());
}

直接上主流程代码

@Override
public  T execute(String serviceId, LoadBalancerRequest request) throws IOException {
	// 获取负载均衡器
	ILoadBalancer loadBalancer = getLoadBalancer(serviceId);
	// 通过负载均衡器，依据相应策略获取服务
	Server server = getServer(loadBalancer);
	if (server == null) {
		throw new IllegalStateException("No instances available for " + serviceId);
	}
	// 封装为ribbonServer
	RibbonServer ribbonServer = new RibbonServer(serviceId, server, isSecure(server,
			serviceId), serverIntrospector(serviceId).getMetadata(server));
	// 执行服务调用
	return execute(serviceId, ribbonServer, request);
}

1. 获取loadBalancer

---

// 是如何获取到的？
// 默认提供的是ZoneAwareLoadBalancer
protected ILoadBalancer getLoadBalancer(String serviceId) {
	return this.clientFactory.getLoadBalancer(serviceId);
}

2. 获取server

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