Play Framework调用控制器导致打开的文件太多错误

Question

我们将Play Framework 2.3.4与Java和Hibernate/Spring一起使用。它在生产中运行了几天，然后突然发生了这种情况：

java.net.SocketException: Too many open files
    at java.net.Socket.createImpl(Socket.java:460)
    at java.net.Socket.getImpl(Socket.java:520)
    at java.net.Socket.setTcpNoDelay(Socket.java:980)
    at com.mysql.jdbc.StandardSocketFactory.configureSocket(StandardSocketFactory.java:134)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:205)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:297)
    ... 75 more

然后是其中一些：

java.io.FileNotFoundException: /opt/psldata-api-1.0.0/app/controllers/StatsController.java (Too many open files)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:138)
    at play.utils.PlayIO$.readFileAsString(PlayIO.scala:63)
    at play.api.Application$$anon$1$$anonfun$input$2.apply(Application.scala:302)
    at play.api.Application$$anon$1$$anonfun$input$2.apply(Application.scala:302)
    at scala.Option.map(Option.scala:145)
    at play.api.Application$$anon$1.input(Application.scala:302)
    at play.api.PlayException$ExceptionSource.interestingLines(PlayException.java:81)
    at views.html.defaultpages.devError$$anonfun$apply$1.apply(devError.template.scala:157)
    at views.html.defaultpages.devError$$anonfun$apply$1.apply(devError.template.scala:142)
    at scala.Option.map(Option.scala:145)
    at views.html.defaultpages.devError$.apply(devError.template.scala:142)
    at play.api.GlobalSettings$$anonfun$devError$1$1.apply(GlobalSettings.scala:141)
    at play.api.GlobalSettings$$anonfun$devError$1$1.apply(GlobalSettings.scala:141)
    at play.api.GlobalSettings$class.onError(GlobalSettings.scala:147)
    at play.core.j.JavaGlobalSettingsAdapter.play$core$j$JavaGlobalSettingsAdapter$$super$onError(JavaGlobalSettingsAdapter.scala:36)
    at play.core.j.JavaGlobalSettingsAdapter$$anonfun$onError$2.apply(JavaGlobalSettingsAdapter.scala:36)
    at play.core.j.JavaGlobalSettingsAdapter$$anonfun$onError$2.apply(JavaGlobalSettingsAdapter.scala:36)
    at scala.Option.getOrElse(Option.scala:120)
    at play.core.j.JavaGlobalSettingsAdapter.onError(JavaGlobalSettingsAdapter.scala:36)
    at play.api.Application$class.handleError(Application.scala:319)
    at play.api.DefaultApplication.handleError(Application.scala:402)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320)
    at scala.Option.map(Option.scala:145)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3.applyOrElse(PlayDefaultUpstreamHandler.scala:320)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3.applyOrElse(PlayDefaultUpstreamHandler.scala:316)
    at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:344)
    at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:343)
    at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
    at play.api.libs.iteratee.Execution$trampoline$.execute(Execution.scala:46)
    at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:40)
    at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:248)
    at scala.concurrent.Promise$class.complete(Promise.scala:55)
    at scala.concurrent.impl.Promise$DefaultPromise.complete(Promise.scala:153)
    at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:23)
    at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:41)

然后是其中的一些：

java.io.FileNotFoundException: /opt/psldata-api-1.0.0/app/controllers/APIController.java (Too many open files)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:138)
    at play.utils.PlayIO$.readFileAsString(PlayIO.scala:63)
    at play.api.Application$$anon$1$$anonfun$input$2.apply(Application.scala:302)
    at play.api.Application$$anon$1$$anonfun$input$2.apply(Application.scala:302)
    at scala.Option.map(Option.scala:145)
    at play.api.Application$$anon$1.input(Application.scala:302)
    at play.api.PlayException$ExceptionSource.interestingLines(PlayException.java:81)
    at views.html.defaultpages.devError$$anonfun$apply$1.apply(devError.template.scala:157)
    at views.html.defaultpages.devError$$anonfun$apply$1.apply(devError.template.scala:142)
    at scala.Option.map(Option.scala:145)
    at views.html.defaultpages.devError$.apply(devError.template.scala:142)
    at play.api.GlobalSettings$$anonfun$devError$1$1.apply(GlobalSettings.scala:141)
    at play.api.GlobalSettings$$anonfun$devError$1$1.apply(GlobalSettings.scala:141)
    at play.api.GlobalSettings$class.onError(GlobalSettings.scala:147)
    at play.core.j.JavaGlobalSettingsAdapter.play$core$j$JavaGlobalSettingsAdapter$$super$onError(JavaGlobalSettingsAdapter.scala:36)
    at play.core.j.JavaGlobalSettingsAdapter$$anonfun$onError$2.apply(JavaGlobalSettingsAdapter.scala:36)
    at play.core.j.JavaGlobalSettingsAdapter$$anonfun$onError$2.apply(JavaGlobalSettingsAdapter.scala:36)
    at scala.Option.getOrElse(Option.scala:120)
    at play.core.j.JavaGlobalSettingsAdapter.onError(JavaGlobalSettingsAdapter.scala:36)
    at play.api.Application$class.handleError(Application.scala:319)
    at play.api.DefaultApplication.handleError(Application.scala:402)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320)
    at scala.Option.map(Option.scala:145)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3.applyOrElse(PlayDefaultUpstreamHandler.scala:320)
    at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3.applyOrElse(PlayDefaultUpstreamHandler.scala:316)
    at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:344)
    at scala.concurrent.Future$$anonfun$recoverWith$1.apply(Future.scala:343)
    at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:32)
    at play.api.libs.iteratee.Execution$trampoline$.execute(Execution.scala:46)
    at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:40)
    at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:248)
    at scala.concurrent.Promise$class.complete(Promise.scala:55)
    at scala.concurrent.impl.Promise$DefaultPromise.complete(Promise.scala:153)
    at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:23)
    at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:41)

因此，基本上所有的事情都会出现这个错误，直到我重新启动应用程序。这看起来像是内存泄漏或什么东西没有正确关闭，但我不知道可能是什么。以前有人犯过这个错误吗？谢谢

Answer 1

我可以从您的文件路径中看到您使用的是Linux，它对您可以打开的文件和套接字的数量有限制，通常设置为1024。可以使用lsof命令计算打开的文件描述符的数量。你遇到的问题是你已经超过了极限。您可以运行lsof -u <playuser> | wc -l进行检查。您可以在/etc/security/limits.conf中看到当前每个用户设置的限制（至少适用于Ubuntu和RedHat）。

如果您有正当理由打开大量文件处理程序或套接字，那么您可以使用ulimit命令来增加限制（ulimit -n将限制设置为系统支持的最大数量）。但如果你没有，而且你确实有泄漏，这只会推迟不可避免的崩溃。

如果没有正当理由打开这么多文件处理程序和套接字，我会检查一下，确保您正在关闭创建的所有套接字，并确保您关闭了所有FileInputStreams。确保在"finally"块中正确关闭它们。在没有看到控制器代码的情况下，我不能确定关闭FileInputStreams是否有问题，但我建议检查它们。

这里还有一个类似的问题，关于套接字限制有更多的细节。