SpringCloud源码剖析-Eureka Client服务续约

/*** Initializes all scheduled tasks.*/privatevoidinitScheduledTasks() {
//如果开启服务注册if (clientConfig.shouldRegisterWithEureka()) {
//续约心跳  30s/次intrenewalIntervalInSecs=instanceInfo.getLeaseInfo().getRenewalIntervalInSecs();
intexpBackOffBound=clientConfig.getHeartbeatExecutorExponentialBackOffBound();
logger.info("Starting heartbeat executor: "+"renew interval is: {}", renewalIntervalInSecs);
// Heartbeat timer//心跳任务scheduler.schedule(
newTimedSupervisorTask(
"heartbeat",
scheduler,
heartbeatExecutor,
renewalIntervalInSecs,
TimeUnit.SECONDS,
expBackOffBound,
newHeartbeatThread()   //HeartbeatThread心跳的线程            ),
renewalIntervalInSecs, TimeUnit.SECONDS);//心跳时间30s/次        ...省略...                    
/**//心跳任务，本身是一个线程对象* The heartbeat task that renews the lease in the given intervals.*/privateclassHeartbeatThreadimplementsRunnable {
publicvoidrun() {
//调用renew()方法续约if (renew()) {
//记录最后续约成功时间lastSuccessfulHeartbeatTimestamp=System.currentTimeMillis();
       }
    }
 }

/**使用Rest请求像Eureak进行服务续约* Renew with the eureka service by making the appropriate REST call*/booleanrenew() {
//Http相应对象EurekaHttpResponse<InstanceInfo>httpResponse;
try {
//使用eurekaTransport得到http客户端，发起心跳请求httpResponse=eurekaTransport.registrationClient.sendHeartBeat(instanceInfo.getAppName(), instanceInfo.getId(), instanceInfo, null);
logger.debug(PREFIX+"{} - Heartbeat status: {}", appPathIdentifier, httpResponse.getStatusCode());
if (httpResponse.getStatusCode() ==404) {
REREGISTER_COUNTER.increment();
logger.info(PREFIX+"{} - Re-registering apps/{}", appPathIdentifier, instanceInfo.getAppName());
longtimestamp=instanceInfo.setIsDirtyWithTime();
//如果续约返回404，尝试重新发起服务注册，并设置Dirtybooleansuccess=register();
if (success) {
instanceInfo.unsetIsDirty(timestamp);
            }
returnsuccess;
        }
returnhttpResponse.getStatusCode() ==200;
    } catch (Throwablee) {
logger.error(PREFIX+"{} - was unable to send heartbeat!", appPathIdentifier, e);
returnfalse;
    }
}

publicabstractclassEurekaHttpClientDecoratorimplementsEurekaHttpClient {
    ...省略...
//发送心跳@OverridepublicEurekaHttpResponse<InstanceInfo>sendHeartBeat(finalStringappName, //服务名finalStringid,//服务IDfinalInstanceInfoinfo,//服务注册对象finalInstanceStatusoverriddenStatus) {  //服务注册状态returnexecute(newRequestExecutor<InstanceInfo>() {
@OverridepublicEurekaHttpResponse<InstanceInfo>execute(EurekaHttpClientdelegate) {
//发送心跳returndelegate.sendHeartBeat(appName, id, info, overriddenStatus);
            }
@OverridepublicRequestTypegetRequestType() {
returnRequestType.SendHeartBeat;
            }
        });
    }

publicabstractclassAbstractJerseyEurekaHttpClientimplementsEurekaHttpClient {
@OverridepublicEurekaHttpResponse<InstanceInfo>sendHeartBeat(StringappName, Stringid, InstanceInfoinfo, InstanceStatusoverriddenStatus) {
StringurlPath="apps/"+appName+'/'+id;
ClientResponseresponse=null;
try {
//webResource是对Web请求的封装WebResourcewebResource=jerseyClient.resource(serviceUrl)
                .path(urlPath)
//服务状态 UP                .queryParam("status", info.getStatus().toString())
//最后刷新时间                .queryParam("lastDirtyTimestamp", info.getLastDirtyTimestamp().toString());
if (overriddenStatus!=null) {
webResource=webResource.queryParam("overriddenstatus", overriddenStatus.name());
            }
BuilderrequestBuilder=webResource.getRequestBuilder();
addExtraHeaders(requestBuilder);
//发送put请求response=requestBuilder.put(ClientResponse.class);
EurekaHttpResponseBuilder<InstanceInfo>eurekaResponseBuilder=anEurekaHttpResponse(response.getStatus(), InstanceInfo.class).headers(headersOf(response));
if (response.hasEntity()) {
eurekaResponseBuilder.entity(response.getEntity(InstanceInfo.class));
            }
returneurekaResponseBuilder.build();
        } finally {
if (logger.isDebugEnabled()) {
logger.debug("Jersey HTTP PUT {}/{}; statusCode={}", serviceUrl, urlPath, response==null?"N/A" : response.getStatus());
            }
if (response!=null) {
response.close();
            }
        }
    }