Nacos集群架构下服务状态变更的设计原理

前言

• 最近一直在研究Nacos开源框架的源码和执行流程原理
• 本次简单聊下AP集群架构下服务状态变动的同步原理

Nacos集群下服务状态变动同步方式

• 客户端服务实例信息在集群节点间同步任务是通过ServiceManager.init()方法，创建一个定时任务线程ServiceReporter执行。

@Component
public class ServiceManager implements RecordListener<Service> {
    
    /**
     * Map(namespace, Map(group::serviceName, Service))
     * 这个map是nacos的注册表结构
     */
    private final Map<String, Map<String, Service>> serviceMap = new ConcurrentHashMap<>();
    
    ......
    /**
     * Init service maneger.
     */
    @PostConstruct
    public void init() {
        // 客户端服务实例信息在集群节点间同步
        GlobalExecutor.scheduleServiceReporter(new ServiceReporter(), 60000, TimeUnit.MILLISECONDS);
        ......
    }
    ......
}
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• ServiceReporter类首先是获取所有客户端实例信息，再获取所有节点信息，然后依次把客户端服务信息发送到其他nacos节点。

注：发起同步的nacos节点是做心跳健康检查的节点

private class ServiceReporter implements Runnable {
    
    @Override
    public void run() {
        try {
            
            // 获取客户端实例信息
            Map<String, Set<String>> allServiceNames = getAllServiceNames();
            
            if (allServiceNames.size() <= 0) {
                //ignore
                return;
            }
            
            for (String namespaceId : allServiceNames.keySet()) {
                
                ServiceChecksum checksum = new ServiceChecksum(namespaceId);
                
                for (String serviceName : allServiceNames.get(namespaceId)) {
                    // 发起同步的节点就是做心跳健康检查的节点
                    if (!distroMapper.responsible(serviceName)) {
                        continue;
                    }
                    
                    Service service = getService(namespaceId, serviceName);
                    
                    if (service == null || service.isEmpty()) {
                        continue;
                    }
                    
                    service.recalculateChecksum();
                    
                    checksum.addItem(serviceName, service.getChecksum());
                }
                
                Message msg = new Message();
                
                msg.setData(JacksonUtils.toJson(checksum));
                
                // 获取所有的集群节点信息
                Collection<Member> sameSiteServers = memberManager.allMembers();
                
                if (sameSiteServers == null || sameSiteServers.size() <= 0) {
                    return;
                }
                
                for (Member server : sameSiteServers) {
                    if (server.getAddress().equals(NetUtils.localServer())) {
                        continue;
                    }
                    
                    // 把客户端服务信息发送到其他nacos节点
                    synchronizer.send(server.getAddress(), msg);
                }
            }
        } catch (Exception e) {
            Loggers.SRV_LOG.error("[DOMAIN-STATUS] Exception while sending service status", e);
        } finally {
            GlobalExecutor.scheduleServiceReporter(this, switchDomain.getServiceStatusSynchronizationPeriodMillis(),
                    TimeUnit.MILLISECONDS);
        }
    }
}
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• 这里的发送http请求用的是ServiceStatusSynchronizer.send()方法

public class ServiceStatusSynchronizer implements Synchronizer {
    
    @Override
    public void send(final String serverIP, Message msg) {
        if (serverIP == null) {
            return;
        }
        // 拼接参数和URL
        Map<String, String> params = new HashMap<String, String>(10);
        
        params.put("statuses", msg.getData());
        params.put("clientIP", NetUtils.localServer());
        
        String url = "http://" + serverIP + ":" + EnvUtil.getPort() + EnvUtil.getContextPath()
                + UtilsAndCommons.NACOS_NAMING_CONTEXT + "/service/status";
        
        if (IPUtil.containsPort(serverIP)) {
            url = "http://" + serverIP + EnvUtil.getContextPath() + UtilsAndCommons.NACOS_NAMING_CONTEXT
                    + "/service/status";
        }
        
        try {
            // 发送同步请求
            HttpClient.asyncHttpPostLarge(url, null, JacksonUtils.toJson(params), new Callback<String>() {
                @Override
                public void onReceive(RestResult<String> result) {
                    if (!result.ok()) {
                        Loggers.SRV_LOG.warn("[STATUS-SYNCHRONIZE] failed to request serviceStatus, remote server: {}",
                                serverIP);
        
                    }
                }
    
                @Override
                public void onError(Throwable throwable) {
                    Loggers.SRV_LOG.warn("[STATUS-SYNCHRONIZE] failed to request serviceStatus, remote server: " + serverIP, throwable);
                }
    
                @Override
                public void onCancel() {
        
                }
            });
        } catch (Exception e) {
            Loggers.SRV_LOG.warn("[STATUS-SYNCHRONIZE] failed to request serviceStatus, remote server: " + serverIP, e);
        }   
    }
}
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最后

• 虚心学习，共同进步-_-