1.ApplicationInfoManager是一个恶汉单利模式的类
/*
* Copyright 2012 Netflix, Inc.
*f
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.netflix.appinfo;
import javax.inject.Inject;
import javax.inject.Singleton;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import com.netflix.appinfo.InstanceInfo.InstanceStatus;
import com.netflix.appinfo.providers.EurekaConfigBasedInstanceInfoProvider;
import com.netflix.discovery.StatusChangeEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The class that initializes information required for registration with
* <tt>Eureka Server</tt> and to be discovered by other components.
*
* <p>
* The information required for registration is provided by the user by passing
* the configuration defined by the contract in {@link EurekaInstanceConfig}
* }.AWS clients can either use or extend {@link CloudInstanceConfig
* }.Other non-AWS clients can use or extend either
* {@link MyDataCenterInstanceConfig} or very basic
* {@link AbstractInstanceConfig}.
* </p>
*
*
* @author Karthik Ranganathan, Greg Kim
*
*/
@Singleton
public class ApplicationInfoManager {
private static final Logger logger = LoggerFactory.getLogger(ApplicationInfoManager.class);
private static ApplicationInfoManager instance = new ApplicationInfoManager();
private InstanceInfo instanceInfo;
private EurekaInstanceConfig config;
protected Map<String, StatusChangeListener> listeners;
private ApplicationInfoManager() {
listeners = new ConcurrentHashMap<String, StatusChangeListener>();
}
/**
* public for spring DI use. This class should be in singleton scope so do not create explicitly.
* Either use DI or use getInstance().initComponent() if not using DI
*/
@Inject
public ApplicationInfoManager(EurekaInstanceConfig config, InstanceInfo instanceInfo) {
this.config = config;
this.instanceInfo = instanceInfo;
this.listeners = new ConcurrentHashMap<String, StatusChangeListener>();
// Hack to allow for getInstance() to use the DI'd ApplicationInfoManager
instance = this;
}
public ApplicationInfoManager(EurekaInstanceConfig config) {
this(config, new EurekaConfigBasedInstanceInfoProvider(config).get());
}
/**
* @deprecated please use DI instead
*/
@Deprecated
public static ApplicationInfoManager getInstance() {
return instance;
}
public void initComponent(EurekaInstanceConfig config) {
try {
this.config = config;
this.instanceInfo = new EurekaConfigBasedInstanceInfoProvider(config).get();
} catch (Throwable e) {
throw new RuntimeException("Failed to initialize ApplicationInfoManager", e);
}
}
/**
* Gets the information about this instance that is registered with eureka.
*
* @return information about this instance that is registered with eureka.
*/
public InstanceInfo getInfo() {
return instanceInfo;
}
public EurekaInstanceConfig getEurekaInstanceConfig() {
return config;
}
/**
* Register user-specific instance meta data. Application can send any other
* additional meta data that need to be accessed for other reasons.The data
* will be periodically sent to the eureka server.
*
* @param appMetadata
* application specific meta data.
*/
public void registerAppMetadata(Map<String, String> appMetadata) {
instanceInfo.registerRuntimeMetadata(appMetadata);
}
/**
* Set the status of this instance. Application can use this to indicate
* whether it is ready to receive traffic. Setting the status here also notifies all registered listeners
* of a status change event.
*
* @param status Status of the instance
*/
public synchronized void setInstanceStatus(InstanceStatus status) {
InstanceStatus prev = instanceInfo.setStatus(status);
if (prev != null) {
for (StatusChangeListener listener : listeners.values()) {
try {
listener.notify(new StatusChangeEvent(prev, status));
} catch (Exception e) {
logger.warn("failed to notify listener: {}", listener.getId(), e);
}
}
}
}
public void registerStatusChangeListener(StatusChangeListener listener) {
listeners.put(listener.getId(), listener);
}
public void unregisterStatusChangeListener(String listenerId) {
listeners.remove(listenerId);
}
/**
* Refetches the hostname to check if it has changed. If it has, the entire
* <code>DataCenterInfo</code> is refetched and passed on to the eureka
* server on next heartbeat.
*
* see {@link InstanceInfo#getHostName()} for explanation on why the hostname is used as the default address
*/
public void refreshDataCenterInfoIfRequired() {
String existingAddress = instanceInfo.getHostName();
String newAddress;
if (config instanceof CloudInstanceConfig) {
// Refresh data center info, and return up to date address
newAddress = ((CloudInstanceConfig) config).resolveDefaultAddress();
} else {
newAddress = config.getHostName(true);
}
String newIp = config.getIpAddress();
if (newAddress != null && !newAddress.equals(existingAddress)) {
logger.warn("The address changed from : {} => {}", existingAddress, newAddress);
// :( in the legacy code here the builder is acting as a mutator.
// This is hard to fix as this same instanceInfo instance is referenced elsewhere.
// We will most likely re-write the client at sometime so not fixing for now.
InstanceInfo.Builder builder = new InstanceInfo.Builder(instanceInfo);
builder.setHostName(newAddress).setIPAddr(newIp).setDataCenterInfo(config.getDataCenterInfo());
instanceInfo.setIsDirty();
}
}
public void refreshLeaseInfoIfRequired() {
LeaseInfo leaseInfo = instanceInfo.getLeaseInfo();
if (leaseInfo == null) {
return;
}
int currentLeaseDuration = config.getLeaseExpirationDurationInSeconds();
int currentLeaseRenewal = config.getLeaseRenewalIntervalInSeconds();
if (leaseInfo.getDurationInSecs() != currentLeaseDuration || leaseInfo.getRenewalIntervalInSecs() != currentLeaseRenewal) {
LeaseInfo newLeaseInfo = LeaseInfo.Builder.newBuilder()
.setRenewalIntervalInSecs(currentLeaseRenewal)
.setDurationInSecs(currentLeaseDuration)
.build();
instanceInfo.setLeaseInfo(newLeaseInfo);
instanceInfo.setIsDirty();
}
}
public static interface StatusChangeListener {
String getId();
void notify(StatusChangeEvent statusChangeEvent);
}
}
2.有两个属性instanceInfo、config，一个监听器listeners，还有一个静态内部接口StatusChangeListener
private InstanceInfo instanceInfo;
private EurekaInstanceConfig config;
protected Map<String, StatusChangeListener> listeners;
public static interface StatusChangeListener {
String getId();
void notify(StatusChangeEvent statusChangeEvent);
}
3.初始化是通过EurekaClientAutoConfiguration完成的（不一定对）
@Configuration
@EnableConfigurationProperties
@ConditionalOnClass(EurekaClientConfig.class)
@ConditionalOnProperty(value = "eureka.client.enabled", matchIfMissing = true)
@AutoConfigureBefore({
NoopDiscoveryClientAutoConfiguration.class,
CommonsClientAutoConfiguration.class })
@AutoConfigureAfter(RefreshAutoConfiguration.class)
public class EurekaClientAutoConfiguration {
@Configuration
@ConditionalOnMissingRefreshScope
protected static class EurekaClientConfiguration {
@Autowired
private ApplicationContext context;
@Autowired(required = false)
private DiscoveryClientOptionalArgs optionalArgs;
@Bean(destroyMethod = "shutdown")
@ConditionalOnMissingBean(value = EurekaClient.class, search = SearchStrategy.CURRENT)
public EurekaClient eurekaClient(ApplicationInfoManager manager,
EurekaClientConfig config) {
return new CloudEurekaClient(manager, config, this.optionalArgs, this.context);
}
@Bean
@ConditionalOnMissingBean(value = ApplicationInfoManager.class, search = SearchStrategy.CURRENT)
public ApplicationInfoManager eurekaApplicationInfoManager(
EurekaInstanceConfig config) {
InstanceInfo instanceInfo = new InstanceInfoFactory().create(config);
return new ApplicationInfoManager(config, instanceInfo);
}
}
}
4.初始化创建InstanceInfo
@CommonsLog
public class InstanceInfoFactory {
public InstanceInfo create(EurekaInstanceConfig config) {
LeaseInfo.Builder leaseInfoBuilder = LeaseInfo.Builder.newBuilder()
.setRenewalIntervalInSecs(config.getLeaseRenewalIntervalInSeconds())
.setDurationInSecs(config.getLeaseExpirationDurationInSeconds());
// Builder the instance information to be registered with eureka
// server
InstanceInfo.Builder builder = InstanceInfo.Builder.newBuilder();
String namespace = config.getNamespace();
if (!namespace.endsWith(".")) {
namespace = namespace + ".";
}
builder.setNamespace(namespace).setAppName(config.getAppname())
.setInstanceId(config.getInstanceId())
.setAppGroupName(config.getAppGroupName())
.setDataCenterInfo(config.getDataCenterInfo())
.setIPAddr(config.getIpAddress()).setHostName(config.getHostName(false))
.setPort(config.getNonSecurePort())
.enablePort(InstanceInfo.PortType.UNSECURE,
config.isNonSecurePortEnabled())
.setSecurePort(config.getSecurePort())
.enablePort(InstanceInfo.PortType.SECURE, config.getSecurePortEnabled())
.setVIPAddress(config.getVirtualHostName())
.setSecureVIPAddress(config.getSecureVirtualHostName())
.setHomePageUrl(config.getHomePageUrlPath(), config.getHomePageUrl())
.setStatusPageUrl(config.getStatusPageUrlPath(),
config.getStatusPageUrl())
.setHealthCheckUrls(config.getHealthCheckUrlPath(),
config.getHealthCheckUrl(), config.getSecureHealthCheckUrl())
.setASGName(config.getASGName());
// Start off with the STARTING state to avoid traffic
if (!config.isInstanceEnabledOnit()) {
InstanceInfo.InstanceStatus initialStatus = InstanceInfo.InstanceStatus.STARTING;
if (log.isInfoEnabled()) {
log.info("Setting initial instance status as: " + initialStatus);
}
builder.setStatus(initialStatus);
}
else {
if (log.isInfoEnabled()) {
log.info("Setting initial instance status as: "
+ InstanceInfo.InstanceStatus.UP
+ ". This may be too early for the instance to advertise itself as available. "
+ "You would instead want to control this via a healthcheck handler.");
}
}
// Add any user-specific metadata information
for (Map.Entry<String, String> mapEntry : config.getMetadataMap().entrySet()) {
String key = mapEntry.getKey();
String value = mapEntry.getValue();
builder.add(key, value);
}
InstanceInfo instanceInfo = builder.build();
instanceInfo.setLeaseInfo(leaseInfoBuilder.build());
return instanceInfo;
}
}
5.初始化StatusChangeListener，在DiscoveryClient初始化的时候赋值的
@Singleton
public class DiscoveryClient implements EurekaClient {
@Inject
DiscoveryClient(ApplicationInfoManager applicationInfoManager, EurekaClientConfig config, DiscoveryClientOptionalArgs args,
Provider<BackupRegistry> backupRegistryProvider) {
initScheduledTasks();
}
private void initScheduledTasks() {
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);
}
if (clientConfig.shouldRegisterWithEureka()) {
int renewalIntervalInSecs = instanceInfo.getLeaseInfo().getRenewalIntervalInSecs();
int expBackOffBound = clientConfig.getHeartbeatExecutorExponentialBackOffBound();
logger.info("Starting heartbeat executor: " + "renew interval is: " + renewalIntervalInSecs);
// Heartbeat timer
scheduler.schedule(
new TimedSupervisorTask(
"heartbeat",
scheduler,
heartbeatExecutor,
renewalIntervalInSecs,
TimeUnit.SECONDS,
expBackOffBound,
new HeartbeatThread()
),
renewalIntervalInSecs, TimeUnit.SECONDS);
// InstanceInfo replicator
instanceInfoReplicator = new InstanceInfoReplicator(
this,
instanceInfo,
clientConfig.getInstanceInfoReplicationIntervalSeconds(),
2); // burstSize
statusChangeListener = new ApplicationInfoManager.StatusChangeListener() {
@Override
public String getId() {
return "statusChangeListener";
}
@Override
public void notify(StatusChangeEvent statusChangeEvent) {
if (InstanceStatus.DOWN == statusChangeEvent.getStatus() ||
InstanceStatus.DOWN == statusChangeEvent.getPreviousStatus()) {
// log at warn level if DOWN was involved
logger.warn("Saw local status change event {}", statusChangeEvent);
} else {
logger.info("Saw local status change event {}", statusChangeEvent);
}
instanceInfoReplicator.onDemandUpdate();
}
};
if (clientConfig.shouldOnDemandUpdateStatusChange()) {
applicationInfoManager.registerStatusChangeListener(statusChangeListener);
}
instanceInfoReplicator.start(clientConfig.getInitialInstanceInfoReplicationIntervalSeconds());
} else {
logger.info("Not registering with Eureka server per configuration");
}
}
}
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