SpringCloud源码解析 (Eureka-Client源码解析) (三)

文章目录

• ​​1.入口​​
• ​​2. EurekaClientAutoConfiguration​​
• ​​3.从服务端获取注册表​​

• ​​3.1 全量获取​​
• ​​3.2 增量获取​​

• ​​4.注册信息​​
• ​​5.initScheduledTasks​​

• ​​5.1 定时更新客户端注册表​​

1.入口

2. EurekaClientAutoConfiguration

RefreshableEurekaClientConfiguration()

eurekaClient() -> CloudEurekaClient cloudEurekaClient = new CloudEurekaClient()

CloudEurekaClient

DiscoveryClient

4个参数:

3个参数:

3.从服务端获取注册表

5参数中间的方法:

private boolean fetchRegistry(boolean forceFullRegistryFetch) {
        Stopwatch tracer = FETCH_REGISTRY_TIMER.start();

        try {
            // If the delta is disabled or if it is the first time, get all
            // applications
            Applications applications = getApplications();

            if (clientConfig.shouldDisableDelta()
                    || (!Strings.isNullOrEmpty(clientConfig.getRegistryRefreshSingleVipAddress()))
                    || forceFullRegistryFetch
                    || (applications == null)
                    || (applications.getRegisteredApplications().size() == 0)
                    || (applications.getVersion() == -1)) //Client application does not have latest library supporting delta
            {
                logger.info("Disable delta property : {}", clientConfig.shouldDisableDelta());
                logger.info("Single vip registry refresh property : {}", clientConfig.getRegistryRefreshSingleVipAddress());
                logger.info("Force full registry fetch : {}", forceFullRegistryFetch);
                logger.info("Application is null : {}", (applications == null));
                logger.info("Registered Applications size is zero : {}",
                        (applications.getRegisteredApplications().size() == 0));
                logger.info("Application version is -1: {}", (applications.getVersion() == -1));
                getAndStoreFullRegistry();
            } else {
                getAndUpdateDelta(applications);
            }
            applications.setAppsHashCode(applications.getReconcileHashCode());
            logTotalInstances();
        } catch (Throwable e) {
            logger.error(PREFIX + "{} - was unable to refresh its cache! status = {}", appPathIdentifier, e.getMessage(), e);
            return false;
        } finally {
            if (tracer != null) {
                tracer.stop();
            }
        }

        // Notify about cache refresh before updating the instance remote status
        onCacheRefreshed();

        // Update remote status based on refreshed data held in the cache
        updateInstanceRemoteStatus();

        // registry was fetched successfully, so return true
        return true;
    }

第一次获取为全量获取, 后面都是增量获取。

3.1 全量获取

这里是一个判断: 如果得到的VIP用户全量为空的话获取全量, 如果不为空的话获取VIP全量

AbstractJerseyEurekaHttpClient.getApplications():

最后发送的是get请求, 获取到注册表

3.2 增量获取

1. getDelta()

2. getAndStoreFullRegistry

3. updateDelta()

4.注册信息

DiscoveryClient -> registry()

boolean register() throws Throwable {
        logger.info(PREFIX + "{}: registering service...", appPathIdentifier);
        EurekaHttpResponse<Void> httpResponse;
        try {
            httpResponse = eurekaTransport.registrationClient.register(instanceInfo);
        } catch (Exception e) {
            logger.warn(PREFIX + "{} - registration failed {}", appPathIdentifier, e.getMessage(), e);
            throw e;
        }
        if (logger.isInfoEnabled()) {
            logger.info(PREFIX + "{} - registration status: {}", appPathIdentifier, httpResponse.getStatusCode());
        }
        return httpResponse.getStatusCode() == Status.NO_CONTENT.getStatusCode();
    }

发送post请求

5.initScheduledTasks

5.1 定时更新客户端注册表

if (clientConfig.shouldFetchRegistry()) {
            // registry cache refresh timer
            int registryFetchIntervalSeconds = clientConfig.getRegistryFetchIntervalSeconds();
            int expBackOffBound = clientConfig.getCacheRefreshExecutorExponentialBackOffBound();
            scheduler.schedule(
                    new TimedSupervisorTask(
                            "cacheRefresh",
                            scheduler,
                            cacheRefreshExecutor,
                            registryFetchIntervalSeconds,
                            TimeUnit.SECONDS,
                            expBackOffBound,
                            new CacheRefreshThread()
                    ),
                    registryFetchIntervalSeconds, TimeUnit.SECONDS);
        }

这里加了锁, 因为这是共享数据, 为迭代稳定性代码。

如果是全量注册的话:同上

如果是增强注册的话:同上