在容器环境中优雅地停止登录

Question

今天我遇到permgen outofmemory错误。

分析表明，webappclassloader最近的GC根是Logback thread：

this     - value: org.apache.catalina.loader.WebappClassLoader #4
  <- contextClassLoader (thread object)     - class: java.lang.Thread, value: org.apache.catalina.loader.WebappClassLoader #4

即：

java.lang.Thread#11 - logback-1

"logback-1" daemon prio=5 tid=34 WAITING
at sun.misc.Unsafe.park(Native Method)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
at java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:458)
at java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:359)
   Local Variable: java.util.concurrent.SynchronousQueue$TransferStack$SNode#1
   Local Variable: java.util.concurrent.SynchronousQueue$TransferStack#6
at java.util.concurrent.SynchronousQueue.take(SynchronousQueue.java:925)
   Local Variable: java.util.concurrent.SynchronousQueue#6
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1068)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
   Local Variable: java.util.concurrent.ThreadPoolExecutor#34
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
   Local Variable: java.util.concurrent.ThreadPoolExecutor$Worker#11
at java.lang.Thread.run(Thread.java:745)

<Context docBase="/home/user/devel/app/src/main/webapp"
         reloadable="true">
    <Resources>
        <!-- To override application.properties and logback.xml -->
        <PreResources className="org.apache.catalina.webresources.DirResourceSet"
                       base="/home/user/devel/app/.config"
                       internalPath="/"
                       webAppMount="/WEB-INF/classes" />
    </Resources>
</Context>

<configuration debug="false" scan="true" scanPeriod="5 seconds">
    <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    ...

在/home/user/devel/app/.config/logback.xml中保存修改后，Tomcat8收到通知（我不确定用于监视fs上的更改的API是什么），然后开始重新部署应用程序。这就是permgen outofmemory之前发生的情况。

如何在容器环境中优雅地停止登录？

如何停止“logback-1”线程？

null

更新我在visualvm中玩堆转储。在从坏的logback-1线程的引用跳转级别下：

lvl1 = flatten(filter(referees(heap.findObject(0xf4c77610)), "!/WebappClassLoader/(classof(it).name)"))

lvl2 = flatten(map(lvl1, "referees(it)"))

lvl3 = flatten(map(lvl2, "referees(it)"))

它指的是

ch.qos.logback.core.util.ExecutorServiceUtil$1

通过插入executorServiceUtil的日志源，我找到了changelog条目：

Answer 1

我不完全明白我该怎么办。当前，我从项目pom.xml中删除了jul-to-SLF4J桥，并删除了以下一行：

<contextListener class="ch.qos.logback.classic.jul.LevelChangePropagator"/>

从logback.xml。即使有了这一行，应用程序也没有“logback-1”线程。

我按建议登记正式文件：

public class ShutdownCleanupListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) { }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        if (LoggerFactory.getILoggerFactory() instanceof LoggerContext) {
            ((LoggerContext) LoggerFactory.getILoggerFactory() ).stop();
        } 
    }
}

<listener>
    <listener-class>com.app.servlet.ShutdownCleanupListener</listener-class>
</listener>

要删除对以下方面的直接依赖，请执行以下操作：

import ch.qos.logback.classic.LoggerContext;

可以使用反射。

不确定我做得对不对。我将查看getpermgen outofmemory是否由于日志返回而出错。

 thread.setName("logback-" + threadNumber.getAndIncrement());

public void stop() {
  // We don't check "started" here, because the executor service uses
  // lazy initialization, rather than being created in the start method
  stopExecutorService();
  started = false;
}