「Webアプリケーション[ROOT]が[com.netflix.hystrix.Hystrix $ 1]タイプのThreadLocalを作成しました」

Question

私は春のブートAPIゲートウェイでNetflixクラウドを使用しています。スタンドアロンで実行することも、Tomcatコンテナにデプロイすることもできます。 Cargo Mavenプラグインを使用してTomcatでspring-bootアプリケーションを再デプロイすると、Tomcat MemoryLeakDetectionは "Webアプリケーション[ROOT]がタイプ[com.netflix.hystrix.Hystrix $ 1]のキーを持つThreadLocalを作成しました。

私のspring-boot appを再デプロイした後、9回Tomcatがメモリ不足になりました。 Hystrix ThreadLocalを削除すると、SpringBootアプリケーションを再デプロイするたびにWebappClassLoaderインスタンスがスティックすることがなくなります。その結果、各再デプロイでHystrix ThreadLocalのためにガベージコレクションできないWebappClassLoaderのインスタンスが残りますか？ここで

は、メモリ不足のスタックトレースです：

29-Apr-2016 12:21:50.721 SEVERE [http-apr-8080-exec-38] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [my-spring-boot-app] created a ThreadLocal with key of type [com.netflix.hystrix.Hystrix$1] (value [com.netflix.hystrix.Hystrix$1@8302924]) and a value of type [java.util.LinkedL 
ist] (value [[]]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak. 
29-Apr-2016 12:22:00.484 INFO [http-apr-8080-exec-38] org.apache.catalina.startup.HostConfig.undeploy Undeploying context [/my-spring-boot-app] 
29-Apr-2016 12:22:09.353 INFO [http-apr-8080-exec-33] org.apache.catalina.startup.HostConfig.deployWAR Deploying web application archive D:\apache-tomcat-8.0.28\webapps\my-spring-boot-app.war 
12:23:08,056 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - debug attribute not set 
12:23:08,089 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - Setting ReconfigureOnChangeFilter scanning period to 30 seconds 
12:23:08,089 |-INFO in ReconfigureOnChangeFilter{invocationCounter=0} - Will scan for changes in [[D:\apache-tomcat-8.0.28\webapps\my-spring-boot-app\WEB-INF\classes\logba 
ck.xml]] every 30 seconds. 
12:23:08,089 |-INFO in ch.qos.logback.classic.joran.action.ConfigurationAction - Adding ReconfigureOnChangeFilter as a turbo filter 
12:23:08,106 |-INFO in ch.qos.logback.core.joran.action.StatusListenerAction - Added status listener of type [ch.qos.logback.core.status.OnConsoleStatusListener] 
12:23:08,118 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - About to instantiate appender of type [ch.qos.logback.core.ConsoleAppender] 
12:23:08,136 |-INFO in ch.qos.logback.core.joran.action.AppenderAction - Naming appender as [CONSOLE] 
12:23:08,176 |-INFO in ch.qos.logback.core.joran.action.NestedComplexPropertyIA - Assuming default type [ch.qos.logback.classic.encoder.PatternLayoutEncoder] for [encoder] property 
java.lang.OutOfMemoryError: Metaspace 
Dumping heap to java_pid15972.hprof ... 
Heap dump file created [206407579 bytes in 1.201 secs] 
29-Apr-2016 12:23:10.870 SEVERE [http-apr-8080-exec-33] org.apache.tomcat.util.modeler.BaseModelMBean.invoke Exception invoking method check 
java.lang.OutOfMemoryError: Metaspace 
     at java.lang.ClassLoader.defineClass1(Native Method) 
     at java.lang.ClassLoader.defineClass(ClassLoader.java:763) 
     at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) 
     at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2496) 
     at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:860) 
     at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1302) 
     at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167) 
     at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:97) 
     at org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:55) 
     at org.slf4j.LoggerFactory.bind(LoggerFactory.java:141) 
     at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:120) 
     at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:331) 
     at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:283) 
     at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:155) 
     at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:132) 
     at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:655) 
     at org.springframework.boot.context.web.SpringBootServletInitializer.onStartup(SpringBootServletInitializer.java:84) 
     at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:175) 

Answer 1

[OK]を、私はTomcatのMemoryLeakDetectionはもはやもうHystrix ThreadLocalの文句を言うように私自身の問題を解決したと思います。私がしたことは、カスタムServletContextListenerを追加し、 "contextDestroyed（）"メソッドで私はcom.netflix.hystrix.HystrixクラスからプライベートスタティックThreadLocalを強制的に削除する方法を見つけました。これは問題を解決するようです。ここに私のカスタムサーブレットリスナーからの抜粋です：

/** 
* The listener interface for receiving ServletContext events. 
* The class that is interested in processing a ServletContext 
* event implements this interface, and the object created 
* with that class is registered with a component using the 
* component's <code>addServletContextListener<code> method. When 
* the ServletContext event occurs, that object's appropriate 
* method is invoked. 
* 
* @see ServletContextEvent 
*/ 
@Component 
public class GatewayServletContextListener implements ServletContextListener{ 

    private static final Logger LOG = LoggerFactory.getLogger(GatewayServletContextListener.class); 

    @Override 
    public void contextInitialized(ServletContextEvent arg0) { 
     LOG.info("Servlet context listener observed context initialized"); 
    } 

    @Override 
    public void contextDestroyed(ServletContextEvent arg0) { 
     LOG.info("Servlet context listener observed context destroyed"); 
     cleanupThreadLocals(); 
    } 



    /** 
    * Cleanup thread locals. 
    */ 
    private void cleanupThreadLocals() { 

     try { 
       LOG.info("Cleaning up ThreadLocals ..."); 

       Field currentCommandField = ReflectionUtils.findField(Hystrix.class, "currentCommand"); 
       Preconditions.checkNotNull(currentCommandField); 

       ReflectionUtils.makeAccessible(currentCommandField); 

       @SuppressWarnings("rawtypes") 
       ThreadLocal currentCommand = (ThreadLocal)currentCommandField.get(null); 

       Preconditions.checkNotNull(currentCommand); 

       currentCommand.remove(); 

       LOG.info("Forcibly removed Hystrix 'currentCommand' ThreadLocal"); 
       LOG.info("Done cleaning up ThreadLocals"); 

      } catch(Exception e) { 
       LOG.warn(e.getMessage(), e); 
      } 

    } 

} 

そして、ここに私の春ブートアプリの再配備にTomcatのログです：

2016-05-03/10:11:08.646/PDT [http-apr-8080-exec-3] INFO x.y.z.listeners.GatewayServletContextListener - Servlet context listener observed context destroyed 
2016-05-03/10:11:08.648/PDT [http-apr-8080-exec-3] INFO x.y.z.listeners.GatewayServletContextListener - Cleaning up ThreadLocals ... 
2016-05-03/10:11:08.652/PDT [http-apr-8080-exec-3] INFO x.y.z.listeners.GatewayServletContextListener - Forcibly removed Hystrix 'currentCommand' ThreadLocal 
2016-05-03/10:11:08.654/PDT [http-apr-8080-exec-3] INFO x.y.z.listeners.GatewayServletContextListener - Done cleaning up ThreadLocals