Felix：部署的包启动两次

【问题标题】：Felix: deployed bundle starts twiceFelix：部署的包启动两次
【发布时间】：2023-03-22 18:20:01
【问题描述】：

我正在使用 Maven（但与 Felix Web 控制台相同的问题）和 maven-sling-plugin 进行部署，我看到它启动了两次：

*INFO* [qtp1462409406-40] logs/access.log 127.0.0.1 - admin 25/Feb/2016:11:18:31 +0100 "POST /dev/system/console/install HTTP/1.1" 200 - "-" "Jakarta Commons-HttpClient/3.1"
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install2994913564032148892.tmp] com.as.test.content BundleEvent INSTALLED
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install2994913564032148892.tmp] com.as.test.content BundleEvent RESOLVED
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install2994913564032148892.tmp] com.as.test.content BundleEvent STARTING
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install2994913564032148892.tmp] com.as.test.content BundleEvent STARTED
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install2994913564032148892.tmp] com.as.test.content Service [com.as.test.jcr.service.NodeFinderImpl,374] ServiceEvent REGISTERED
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install2994913564032148892.tmp] com.as.test.content Service [com.as.test.jcr.service.NodeSorterImpl,375] ServiceEvent REGISTERED
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install2994913564032148892.tmp] com.as.test.content Service [com.as.test.jcr.service.UserProcessorImpl,376] ServiceEvent REGISTERED

====> Starts executing code: creates users, sets permissions and sort nodes with the JCR API
[...]
*ERROR* [pool-7-thread-1] com.as.test.content [com.as.test.jcr.service.ContentInitializerImpl(173)] Failed creating the component instance; see log for reason
*INFO* [FelixFrameworkWiring] com.as.test.content BundleEvent STOPPING
*INFO* [FelixFrameworkWiring] com.as.test.content Service [com.as.test.jcr.service.ContentInitializerImpl,383] ServiceEvent UNREGISTERING
*INFO* [FelixFrameworkWiring] com.as.test.content Service [com.as.test.jcr.service.NodeSorterImpl,375] ServiceEvent UNREGISTERING
*INFO* [FelixFrameworkWiring] com.as.test.content Service [com.as.test.jcr.service.UserProcessorImpl,376] ServiceEvent UNREGISTERING
*INFO* [FelixFrameworkWiring] com.as.test.content Service [com.as.test.jcr.service.NodeFinderImpl,374] ServiceEvent UNREGISTERING
*INFO* [FelixFrameworkWiring] com.as.test.content BundleEvent STOPPED
*INFO* [FelixFrameworkWiring] com.as.test.content BundleEvent UNRESOLVED
*INFO* [FelixFrameworkWiring] com.as.test.content BundleEvent RESOLVED
*INFO* [FelixFrameworkWiring] com.as.test.content BundleEvent STARTING
*INFO* [FelixFrameworkWiring] org.apache.sling.jcr.contentloader.internal.Loader Content of bundle already loaded com.as.test.content.
*INFO* [FelixFrameworkWiring] com.as.test.content BundleEvent STARTED
*INFO* [FelixFrameworkWiring] com.as.test.content Service [com.as.test.jcr.service.NodeFinderImpl,384] ServiceEvent REGISTERED
*INFO* [FelixFrameworkWiring] com.as.test.content Service [com.as.test.jcr.service.NodeSorterImpl,385] ServiceEvent REGISTERED
*INFO* [FelixFrameworkWiring] com.as.test.content Service [com.as.test.jcr.service.ContentInitializerImpl,387] ServiceEvent REGISTERED
*INFO* [FelixFrameworkWiring] com.as.test.jcr.service.ContentInitializerImpl Initializing Sling content
====> Starts (again) executing code: creates users, sets permissions and sort nodes with the JCR API

我在bundle的启动时执行了一些代码，它在中间停止，然后重新启动，我找不到原因。

我尝试过使用 Sling 启动板 7 和 8，分别使用 org.apache.felix.framework 4.4.1 和 5.2.0

编辑：堆栈跟踪

1. Starts from background install
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   java.lang.Thread.getAllStackTraces(Thread.java:1640)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   com.as.test.Activator.printStrackTraces(Activator.java:33)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   com.as.test.Activator.start(Activator.java:23)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:645)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.framework.Felix.activateBundle(Felix.java:2154)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.framework.Felix.startBundle(Felix.java:2072)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.framework.BundleImpl.start(BundleImpl.java:976)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.framework.BundleImpl.start(BundleImpl.java:963)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.webconsole.internal.core.InstallHelper.doRun(InstallHelper.java:67)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.webconsole.internal.core.BaseUpdateInstallHelper.doRun(    BaseUpdateInstallHelper.java:89)
*INFO* [Background Install /var/folders/v0/gh9_k3ld5vx43sn057mg6h3c0000gn/T/install3836459285044407564.tmp] com.as.test.Activator   org.apache.felix.webconsole.internal.core.BaseUpdateInstallHelper.run(    BaseUpdateInstallHelper.java:121)

2. Stops from FelixFrameworkWiring
*INFO* [FelixFrameworkWiring] com.as.test.Activator THREAD: Thread[FelixFrameworkWiring,5,main]
*INFO* [FelixFrameworkWiring] com.as.test.Activator   java.lang.Thread.dumpThreads(Native Method)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   java.lang.Thread.getAllStackTraces(Thread.java:1640)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   com.as.test.Activator.printStrackTraces(Activator.java:33)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   com.as.test.Activator.start(Activator.java:23)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:645)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix.activateBundle(Felix.java:2154)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix.startBundle(Felix.java:2072)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix$RefreshHelper.restart(Felix.java:4911)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix.refreshPackages(Felix.java:4148)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.FrameworkWiringImpl.run(FrameworkWiringImpl.java:178)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   java.lang.Thread.run(Thread.java:745)

3. Restarts from FelixFrameworkWiring
*INFO* [FelixFrameworkWiring] com.as.test.Activator THREAD: Thread[FelixFrameworkWiring,5,main]
*INFO* [FelixFrameworkWiring] com.as.test.Activator   java.lang.Thread.dumpThreads(Native Method)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   java.lang.Thread.getAllStackTraces(Thread.java:1640)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   com.as.test.Activator.printStrackTraces(Activator.java:33)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   com.as.test.Activator.start(Activator.java:23)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:645)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix.activateBundle(Felix.java:2154)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix.startBundle(Felix.java:2072)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix$RefreshHelper.restart(Felix.java:4911)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.Felix.refreshPackages(Felix.java:4148)
*INFO* [FelixFrameworkWiring] com.as.test.Activator   org.apache.felix.framework.FrameworkWiringImpl.run(FrameworkWiringImpl.java:178)

【问题讨论】：

  • 如果我是你，我会写一个 Bundle Activator，然后简单地将 start 和 stop 方法的堆栈跟踪从这些方法打印到控制台。从堆栈跟踪中，您可以找出正在发生的事情。可能是某种神奇的技术可以编织，但也可能有其他原因。
  • 我认为你的 pom.xml 有这方面的作用，你能检查一下吗？
  • 我将尝试激活器并打印堆栈跟踪。我应该在 pom 中检查什么？
  • 我已将激活器的堆栈跟踪添加到我的问题中。我真的不知道该怎么办，我看到涉及两个进程，Background installed 和 FelixFrameworkWiring 但我不知道为什么它们都启动我的包。
  • 猜猜你的bundle是先启动的，然后一些bundle被移除/安装，然后刷新被调用，因为你的bundle被重新连接到其他包。接线的不同之处可能很有趣（如果有的话）。我现在在activate函数中写出下面的结果，看看有没有变化：bundleContext.getBundle().adapt(BundleWiring.class).getRequiredWires(null);

标签： osgi apache-felix sling


【解决方案1】：

最好是让您的捆绑包为这种情况做好准备。许多事情都可能导致捆绑包多次启动，这不应该是例外情况。

【讨论】：

  • 感谢 Bertrand 的意见。我真的不知道该怎么做，因为它在我的代码执行中间重新启动（通常使用 JCR API 设置权限，就像这里所说的 stackoverflow.com/questions/21380400/…）所以突然对我的节点查找服务的引用为空，并且我不知道我应该用什么来处理这种情况。
  • 每次我使用对 API 的引用（主要是 Jackrabbit API）时，我都添加了空值检查，因此它不会抛出 NullPointerException，并且只是在没有异常的情况下重新启动，但我想知道你是否必须当您使用引用时，请始终这样做，如果这就是您所说的“为这种情况做好准备”的意思。我可能必须了解 OSGi :)
  • 您是否看到通过@Reference 获得的服务变为空？理论上这不应该发生AFAIK，你的组件应该被停用。如果您可以将示例简化为最简单的失败案例，我们或许可以解释原因。
  • 是的，当调用通过@Reference 获得的服务时，我会在某些时候出现getNullPointerException。我试图创建一个小包来重现该行为，但我无法做到。基本上，我在真正的捆绑包中所做的是查找页面类型资源，按其父资源（即文档）对它们进行分组，然后使用 JCR API 在属性上对它们进行排序。在此期间，bundle 重新启动，我用来查询 JCR 的服务变为 null，而我的代码仍在执行。
  • 将日志记录添加到组件的 deactivate 方法（或在需要时添加这样的方法）以检查它是否在引用变为 null 之前被停用可能会很有趣。理论上它应该，这将是一种让您检测到组件应该停止执行它所做的任何事情的方法。
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