关于eureka:Eureka-服务续约和注册

服务续约

服务续约的线程和 Eureka – 服务发现中的一样，这里不再解说，咱们间接通过 HeartbeatThread 的 run 办法看 renew 办法。

boolean renew() {
    EurekaHttpResponse<InstanceInfo> httpResponse;
    try {
        // 调用 EurekaServer 地址 +"apps/" + appName + '/' + id
        httpResponse = eurekaTransport.registrationClient.sendHeartBeat(instanceInfo.getAppName(), instanceInfo.getId(), instanceInfo, null);
        logger.debug(PREFIX + "{} - Heartbeat status: {}", appPathIdentifier, httpResponse.getStatusCode());
        if (httpResponse.getStatusCode() == Status.NOT_FOUND.getStatusCode()) {REREGISTER_COUNTER.increment();
            logger.info(PREFIX + "{} - Re-registering apps/{}", appPathIdentifier, instanceInfo.getAppName());
            long timestamp = instanceInfo.setIsDirtyWithTime();
            boolean success = register();
            if (success) {instanceInfo.unsetIsDirty(timestamp);
            }
            return success;
        }
        return httpResponse.getStatusCode() == Status.OK.getStatusCode();
    } catch (Throwable e) {logger.error(PREFIX + "{} - was unable to send heartbeat!", appPathIdentifier, e);
        return false;
    }
}

服务注册

在 Eureka – Client 服务启动中提到 initScheduledTasks 中会调用 InstanceInfoReplicator#start 办法。

public void start(int initialDelayMs) {if (started.compareAndSet(false, true)) {instanceInfo.setIsDirty();  // for initial register
        Future next = scheduler.schedule(this, initialDelayMs, TimeUnit.SECONDS);
        scheduledPeriodicRef.set(next);
    }
}

start 办法会启动一个定时工作，就会调用 InstanceInfoReplicator#run 办法。refreshInstanceInfo 会刷新数据中心信息和租约信息。

public void run() {
    try {
        // 刷新数据中心信息和租约信息。discoveryClient.refreshInstanceInfo();

        Long dirtyTimestamp = instanceInfo.isDirtyWithTime();
        // 如果信息有变动，则注册
        if (dirtyTimestamp != null) {// 注册,"apps/" + info.getAppName()
            discoveryClient.register();
            instanceInfo.unsetIsDirty(dirtyTimestamp);
        }
    } catch (Throwable t) {logger.warn("There was a problem with the instance info replicator", t);
    } finally {
        // 线程用于刷新信息以及从新注册
        Future next = scheduler.schedule(this, replicationIntervalSeconds, TimeUnit.SECONDS);
        scheduledPeriodicRef.set(next);
    }
}

完结

直至，服务注册、服务发现、服务续约，client 局部曾经讲完了。