private Response getInstanceResponse()

in spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-nacos-discovery/src/main/java/com/alibaba/cloud/nacos/loadbalancer/NacosLoadBalancer.java [134:184]

44 lines of code
7 McCabe index (conditional complexity)


	private Response<ServiceInstance> getInstanceResponse(Request<?> request,
			List<ServiceInstance> serviceInstances) {
		if (serviceInstances.isEmpty()) {
			log.warn("No servers available for service: {}", this.serviceId);
			return new EmptyResponse();
		}

		try {
			String clusterName = this.nacosDiscoveryProperties.getClusterName();

			List<ServiceInstance> instancesToChoose = serviceInstances;
			if (StringUtils.isNotBlank(clusterName)) {
				List<ServiceInstance> sameClusterInstances = serviceInstances.stream()
						.filter(serviceInstance -> {
							String cluster = serviceInstance.getMetadata()
									.get("nacos.cluster");
							return StringUtils.equals(cluster, clusterName);
						}).collect(Collectors.toList());
				if (!CollectionUtils.isEmpty(sameClusterInstances)) {
					instancesToChoose = sameClusterInstances;
				}
			}
			else {
				log.warn(
						"A cross-cluster call occurs，name = {}, clusterName = {}, instance = {}",
						serviceId, clusterName, serviceInstances);
			}
			instancesToChoose = this.filterInstanceByIpType(instancesToChoose);

			// Filter the service list sequentially based on the order number
			for (ServiceInstanceFilter filter : serviceInstanceFilters) {
				instancesToChoose = filter.filterInstance(request, instancesToChoose);
			}

			ServiceInstance instance;
			// Find the corresponding load balancing algorithm through the service ID and select the final service instance
			if (loadBalancerAlgorithmMap.containsKey(serviceId)) {
				instance = loadBalancerAlgorithmMap.get(serviceId).getInstance(request, instancesToChoose);
			}
			else {
				instance = loadBalancerAlgorithmMap.get(LoadBalancerAlgorithm.DEFAULT_SERVICE_ID)
						.getInstance(request, instancesToChoose);
			}

			return new DefaultResponse(instance);
		}
		catch (Exception e) {
			log.warn("NacosLoadBalancer error", e);
			return null;
		}
	}