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Ensure Eureka server gets iniialized with non-zero count

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The problem is pretty deep here so I hope I did something sane. Basically if
PeerAwareInstanceRegistry.openForTraffic(int) ever gets called with a 0 argument
it resets the threshold for numberOfRenewsPerMinThreshold to 0 from which
it only ever recovers if the same method is called again with a non-zero argument.
For a standalone server this means that it will never automatically expire
any leases (only when it chats to its neighbours and finds out they have
registered services will it ever switch the threshold back on).

Another problem (unsolved) is that the reset mechanism will kick back in
occasionally (resetting to 1 with this change, but that's probably also
a bad thing). And when there *are* actually peers to talk to unless they are
in AWS they will never communicate correctly about the actual number of local
services (the criteria for that are deeply connected with AWS and EIP).

Fixes gh-6
This commit is contained in:
Dave Syer
2014-09-16 18:12:03 +01:00
parent 91c9ab1d5f
commit 191bad05ec
2 changed files with 152 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

196
spring-cloud-netflix-eureka-server/src/main/java/org/springframework/cloud/netflix/eureka/server/EurekaServerInitializerConfiguration.java
View File

@@ -21,6 +21,10 @@ import java.lang.reflect.Modifier;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
@@ -31,10 +35,11 @@ import org.springframework.cloud.netflix.eureka.event.EurekaRegistryAvailableEve
import org.springframework.cloud.netflix.eureka.event.EurekaServerStartedEvent;
import org.springframework.cloud.netflix.eureka.event.LeaseManagerMessageBroker;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.SmartLifecycle;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.event.SmartApplicationListener;
import org.springframework.core.Ordered;
import org.springframework.util.ReflectionUtils;
import org.springframework.web.context.ServletContextAware;
@@ -55,6 +60,9 @@ import com.netflix.eureka.lease.LeaseManager;
public class EurekaServerInitializerConfiguration implements ServletContextAware,
SmartLifecycle, Ordered {
private static Log logger = LogFactory
.getLog(EurekaServerInitializerConfiguration.class);
@Autowired
private EurekaServerConfig eurekaServerConfig;
@@ -77,18 +85,27 @@ public class EurekaServerInitializerConfiguration implements ServletContextAware
new Thread(new Runnable() {
@Override
public void run() {
new EurekaBootStrap() {
@Override
protected void initEurekaEnvironment() {
LoggingConfiguration.getInstance().configure();
EurekaServerConfigurationManager.getInstance()
.setConfiguration(eurekaServerConfig);
//PeerAwareInstanceRegistry.getInstance();
applicationContext.publishEvent(new EurekaRegistryAvailableEvent(eurekaServerConfig));
}
}.contextInitialized(new ServletContextEvent(servletContext));
running = true;
applicationContext.publishEvent(new EurekaServerStartedEvent(eurekaServerConfig));
try {
new EurekaBootStrap() {
@Override
protected void initEurekaEnvironment() {
LoggingConfiguration.getInstance().configure();
EurekaServerConfigurationManager.getInstance()
.setConfiguration(eurekaServerConfig);
// PeerAwareInstanceRegistry.getInstance();
applicationContext
.publishEvent(new EurekaRegistryAvailableEvent(
eurekaServerConfig));
}
}.contextInitialized(new ServletContextEvent(servletContext));
running = true;
applicationContext.publishEvent(new EurekaServerStartedEvent(
eurekaServerConfig));
}
catch (Exception e) {
// Help!
logger.error("Could not initialize Eureka servlet context", e);
}
}
}).start();
}
@@ -123,41 +140,130 @@ public class EurekaServerInitializerConfiguration implements ServletContextAware
return order;
}
@Configuration
@ConditionalOnClass(PeerAwareInstanceRegistry.class)
protected static class Initializer implements
ApplicationListener<EurekaRegistryAvailableEvent> {
@Configuration
@ConditionalOnClass(PeerAwareInstanceRegistry.class)
protected static class RegistryInstanceProxyInitializer implements
SmartApplicationListener {
@Autowired
private ApplicationContext applicationContext;
@Autowired
private ApplicationContext applicationContext;
@Bean
public LeaseManagerMessageBroker leaseManagerMessageBroker() {
return new LeaseManagerMessageBroker();
}
private PeerAwareInstanceRegistry instance;
@Override
public void onApplicationEvent(EurekaRegistryAvailableEvent event) {
//wrap the instance registry...
ProxyFactory factory = new ProxyFactory(PeerAwareInstanceRegistry.getInstance());
//...with the LeaseManagerMessageBroker
factory.addAdvice(new PiggybackMethodInterceptor(leaseManagerMessageBroker(), LeaseManager.class));
factory.setProxyTargetClass(true);
@Bean
public LeaseManagerMessageBroker leaseManagerMessageBroker() {
return new LeaseManagerMessageBroker();
}
//Now replace the PeerAwareInstanceRegistry with our wrapped version
Field field = ReflectionUtils.findField(PeerAwareInstanceRegistry.class, "instance");
try {
// Awful ugly hack to work around lack of DI in eureka
field.setAccessible(true);
Field modifiersField = Field.class.getDeclaredField("modifiers");
modifiersField.setAccessible(true);
modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
ReflectionUtils.setField(field, null, factory.getProxy());
}
catch (Exception e) {
throw new IllegalStateException("Cannot modify instance registry", e);
}
}
@Override
public void onApplicationEvent(ApplicationEvent event) {
if (instance == null) {
instance = PeerAwareInstanceRegistry.getInstance();
// Our instance is the un-proxied version so we can hack it
expectRegistrations(1);
}
if (event instanceof EurekaServerStartedEvent) {
// Do it again in case this message came in late
expectRegistrations(1);
}
else {
replaceInstance(getProxyForInstance());
}
}
}
private void replaceInstance(Object proxy) {
Field field = ReflectionUtils.findField(PeerAwareInstanceRegistry.class,
"instance");
try {
// Awful ugly hack to work around lack of DI in eureka
field.setAccessible(true);
Field modifiersField = Field.class.getDeclaredField("modifiers");
modifiersField.setAccessible(true);
modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
ReflectionUtils.setField(field, null, proxy);
}
catch (Exception e) {
throw new IllegalStateException("Cannot modify instance registry", e);
}
}
private Object getProxyForInstance() {
// Wrap the instance registry...
ProxyFactory factory = new ProxyFactory(instance);
// ...with the LeaseManagerMessageBroker
factory.addAdvice(new PiggybackMethodInterceptor(leaseManagerMessageBroker(),
LeaseManager.class));
factory.addAdvice(new TrafficOpener());
factory.setProxyTargetClass(true);
return factory.getProxy();
}
private void expectRegistrations(int count) {
/*
* Setting expectedNumberOfRenewsPerMin to non-zero to ensure that even an
* isolated server can adjust its eviction policy to the number of
* registrations (when it's zero, even a successful registration won't reset
* the rate threshold in InstanceRegistry.register()).
*/
Field field = ReflectionUtils.findField(PeerAwareInstanceRegistry.class,
"expectedNumberOfRenewsPerMin");
try {
// Awful ugly hack to work around lack of DI in eureka
field.setAccessible(true);
int value = (int) ReflectionUtils.getField(field, instance);
if (value == 0 && count > 0) {
ReflectionUtils.setField(field, instance, count);
}
}
catch (Exception e) {
throw new IllegalStateException(
"Cannot modify instance registry expected renews", e);
}
}
@Override
public int getOrder() {
return 0;
}
@Override
public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
return eventType.isAssignableFrom(EurekaServerStartedEvent.class)
|| eventType.isAssignableFrom(EurekaRegistryAvailableEvent.class);
}
@Override
public boolean supportsSourceType(Class<?> sourceType) {
return true;
}
}
/**
* Additional aspect for intercepting method invocations on PeerAwareInstanceRegistry.
* If {@link PeerAwareInstanceRegistry#openForTraffic(int)} is called with a zero
* argument, it means that leases are not automatically cancelled if the instance
* hasn't sent any renewals recently. This happens for a standalone server. It seems
* like a bad default, so we set it to the smallest non-zero value we can, so that any
* instances that subsequently register can bump up the threshold.
*
* @author Dave Syer
*
*/
protected static class TrafficOpener implements MethodInterceptor {
@Override
public Object invoke(MethodInvocation invocation) throws Throwable {
if ("openForTraffic".equals(invocation.getMethod().getName())) {
int count = (int) invocation.getArguments()[0];
if (count == 0) {
ReflectionUtils.invokeMethod(invocation.getMethod(),
invocation.getThis(), 1);
return null;
}
}
return invocation.proceed();
}
}
}

2
spring-cloud-netflix-eureka-server/src/test/java/org/springframework/cloud/netflix/eureka/server/ApplicationTests.java
View File

@@ -22,7 +22,7 @@ import org.springframework.test.context.web.WebAppConfiguration;
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = Application.class)
@WebAppConfiguration
@IntegrationTest({ "server.port=0", "spring.application.name=eureka", "management.contextPath=/admin" })
@IntegrationTest({ "server.port=0", "spring.application.name=eureka", "management.contextPath=/admin", "spring.jmx.enabled=true" })
public class ApplicationTests {
@Value("${local.server.port}")