開啓eureka client的註解@EnableDiscoveryClient的功能類DiscoveryClient梳理圖
獲取server url位於類EndpointUtils的getServiceUrlsMapFromConfig方法上
public static Map<String, List<String>> getServiceUrlsMapFromConfig(EurekaClientConfig clientConfig, String instanceZone, boolean preferSameZone) {
Map<String, List<String>> orderedUrls = new LinkedHashMap();
//獲取regin，一個微服務應用只有一個region
String region = getRegion(clientConfig);
//獲取zone，一個微服務能夠有多個zone
String[] availZones = clientConfig.getAvailabilityZones(clientConfig.getRegion());
if (availZones == null || availZones.length == 0) {
//若是zone爲null,就設置爲default
availZones = new String[]{"default"};
}
logger.debug("The availability zone for the given region {} are {}", region, Arrays.toString(availZones));
int myZoneOffset = getZoneOffset(instanceZone, preferSameZone, availZones);
String zone = availZones[myZoneOffset];
//根據region和zone得出server url， 而且能夠配置多個server url
List<String> serviceUrls = clientConfig.getEurekaServerServiceUrls(zone);
if (serviceUrls != null) {
orderedUrls.put(zone, serviceUrls);
}
int currentOffset = myZoneOffset == availZones.length - 1 ? 0 : myZoneOffset + 1;
while(currentOffset != myZoneOffset) {
zone = availZones[currentOffset];
serviceUrls = clientConfig.getEurekaServerServiceUrls(zone);
if (serviceUrls != null) {
orderedUrls.put(zone, serviceUrls);
}
if (currentOffset == availZones.length - 1) {
currentOffset = 0;
} else {
++currentOffset;
}
}
if (orderedUrls.size() < 1) {
throw new IllegalArgumentException("DiscoveryClient: invalid serviceUrl specified!");
} else {
return orderedUrls;
}
}
服務註冊DiscoveryClient initScheduledTasks方法
private void initScheduledTasks() {
int renewalIntervalInSecs;
int expBackOffBound;
if (this.clientConfig.shouldFetchRegistry()) {
renewalIntervalInSecs = this.clientConfig.getRegistryFetchIntervalSeconds();
expBackOffBound = this.clientConfig.getCacheRefreshExecutorExponentialBackOffBound();
this.scheduler.schedule(new TimedSupervisorTask("cacheRefresh", this.scheduler, this.cacheRefreshExecutor, renewalIntervalInSecs, TimeUnit.SECONDS, expBackOffBound, new DiscoveryClient.CacheRefreshThread()), (long)renewalIntervalInSecs, TimeUnit.SECONDS);
}
//配置文件註冊服務
if (this.clientConfig.shouldRegisterWithEureka()) {
renewalIntervalInSecs = this.instanceInfo.getLeaseInfo().getRenewalIntervalInSecs();
expBackOffBound = this.clientConfig.getHeartbeatExecutorExponentialBackOffBound();
logger.info("Starting heartbeat executor: renew interval is: " + renewalIntervalInSecs);
this.scheduler.schedule(new TimedSupervisorTask("heartbeat", this.scheduler, this.heartbeatExecutor, renewalIntervalInSecs, TimeUnit.SECONDS, expBackOffBound, new DiscoveryClient.HeartbeatThread()), (long)renewalIntervalInSecs, TimeUnit.SECONDS);
this.instanceInfoReplicator = new InstanceInfoReplicator(this, this.instanceInfo, this.clientConfig.getInstanceInfoReplicationIntervalSeconds(), 2);
this.statusChangeListener = new StatusChangeListener() {
public String getId() {
return "statusChangeListener";
}
public void notify(StatusChangeEvent statusChangeEvent) {
if (InstanceStatus.DOWN != statusChangeEvent.getStatus() && InstanceStatus.DOWN != statusChangeEvent.getPreviousStatus()) {
DiscoveryClient.logger.info("Saw local status change event {}", statusChangeEvent);
} else {
DiscoveryClient.logger.warn("Saw local status change event {}", statusChangeEvent);
}
DiscoveryClient.this.instanceInfoReplicator.onDemandUpdate();
}
};
if (this.clientConfig.shouldOnDemandUpdateStatusChange()) {
this.applicationInfoManager.registerStatusChangeListener(this.statusChangeListener);
}
//開啓一個任務
this.instanceInfoReplicator.start(this.clientConfig.getInitialInstanceInfoReplicationIntervalSeconds());
} else {
logger.info("Not registering with Eureka server per configuration");
}
}
上面代碼中 this.instanceInfoReplicator.start(this.clientConfig.getInitialInstanceInfoReplicationIntervalSeconds());開啓了一個任務，該任務的代碼以下app
public void run() {
boolean var6 = false;
ScheduledFuture next;
label53: {
try {
var6 = true;
this.discoveryClient.refreshInstanceInfo();
Long dirtyTimestamp = this.instanceInfo.isDirtyWithTime();
if (dirtyTimestamp != null) {
//真正觸發了註冊
this.discoveryClient.register();
this.instanceInfo.unsetIsDirty(dirtyTimestamp);
var6 = false;
} else {
var6 = false;
}
break label53;
} catch (Throwable var7) {
logger.warn("There was a problem with the instance info replicator", var7);
var6 = false;
} finally {
if (var6) {
ScheduledFuture next = this.scheduler.schedule(this, (long)this.replicationIntervalSeconds, TimeUnit.SECONDS);
this.scheduledPeriodicRef.set(next);
}
}
next = this.scheduler.schedule(this, (long)this.replicationIntervalSeconds, TimeUnit.SECONDS);
this.scheduledPeriodicRef.set(next);
return;
}
next = this.scheduler.schedule(this, (long)this.replicationIntervalSeconds, TimeUnit.SECONDS);
this.scheduledPeriodicRef.set(next);
}
真正觸發了註冊的代碼爲this.discoveryClient.register(); 註冊的代碼爲：微服務
boolean register() throws Throwable {
logger.info("DiscoveryClient_" + this.appPathIdentifier + ": registering service...");
EurekaHttpResponse httpResponse;
try {
//經過REST請求進行註冊
httpResponse = this.eurekaTransport.registrationClient.register(this.instanceInfo);
} catch (Exception var3) {
logger.warn("{} - registration failed {}", new Object[]{"DiscoveryClient_" + this.appPathIdentifier, var3.getMessage(), var3});
throw var3;
}
if (logger.isInfoEnabled()) {
logger.info("{} - registration status: {}", "DiscoveryClient_" + this.appPathIdentifier, httpResponse.getStatusCode());
}
return httpResponse.getStatusCode() == 204;
}