带有 VPC 的 AWS Lambda Play Scala 项目引发 UnknownHostException

Question

我正在尝试根据示例 here 将 scala Play 应用程序作为 AWS Lambda 函数运行 该类是一个简单的函数：

 class PlayTask {

  // AWS Lambda Handler
  def exec(event: S3Event): String = WithApplication { App =>
    Play.current.configuration.getString("Play.Lambda.Greet").getOrElse("")
  }

  private def WithApplication[A](f: Application => A): A = {
    val env = Environment(new java.io.File("."), getClass.getClassLoader, Mode.Prod)
    val context = ApplicationLoader.createContext(env)
    val app = ApplicationLoader(context).load(context)
    try {
      Play.start(app)
      f(app)
    } finally {
      Play.stop(app)
    }
  }
}

jar 被加载到 S3 容器并连接到 VPC 以访问 RDS 和互联网。 但是，在连接 VPC 并运行 S3 put test 时，出现以下错误。

    at com.google.inject.internal.MembersInjectorImpl.injectMembers(MembersInjectorImpl.java:132) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl$1.call(MembersInjectorImpl.java:93) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl$1.call(MembersInjectorImpl.java:80) [task/:na] 
 at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1103) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl.injectAndNotify(MembersInjectorImpl.java:80) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl.injectMembers(MembersInjectorImpl.java:62) [task/:na] 
 at com.google.inject.internal.InjectorImpl.injectMembers(InjectorImpl.java:984) [task/:na] 
 at com.google.inject.util.Providers$GuicifiedProviderWithDependencies.initialize(Providers.java:149) [task/:na] 
 at com.google.inject.util.Providers$GuicifiedProviderWithDependencies$$FastClassByGuice$$2a7177aa.invoke(<generated>) [task/:na] 
 at com.google.inject.internal.cglib.reflect.$FastMethod.invoke(FastMethod.java:53) [task/:na] 
 at com.google.inject.internal.SingleMethodInjector$1.invoke(SingleMethodInjector.java:57) [task/:na] 
 at com.google.inject.internal.SingleMethodInjector.inject(SingleMethodInjector.java:91) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl.injectMembers(MembersInjectorImpl.java:132) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl$1.call(MembersInjectorImpl.java:93) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl$1.call(MembersInjectorImpl.java:80) [task/:na] 
 at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1092) [task/:na] 
 at com.google.inject.internal.MembersInjectorImpl.injectAndNotify(MembersInjectorImpl.java:80) [task/:na] 
 at com.google.inject.internal.Initializer$InjectableReference.get(Initializer.java:174) [task/:na] 
 at com.google.inject.internal.Initializer.injectAll(Initializer.java:108) [task/:na] 
 at com.google.inject.internal.InternalInjectorCreator.injectDynamically(InternalInjectorCreator.java:174) [task/:na] 
 at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:110) [task/:na] 
 at com.google.inject.Guice.createInjector(Guice.java:96) [task/:na] 
 at com.google.inject.Guice.createInjector(Guice.java:73) [task/:na] 
 at com.google.inject.Guice.createInjector(Guice.java:62) [task/:na] 
 at play.api.inject.guice.GuiceBuilder.injector(GuiceInjectorBuilder.scala:126) [task/:na] 
 at play.api.inject.guice.GuiceApplicationBuilder.build(GuiceApplicationBuilder.scala:93) [task/:na] 
 at play.api.inject.guice.GuiceApplicationLoader.load(GuiceApplicationLoader.scala:21) [task/:na] 
 at example.PlayTask.WithApplication(PlayTask.scala:16) [task/:na] 
 at example.PlayTask.exec(PlayTask.scala:9) [task/:na] 
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_71] 
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_71] 
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_71] 
 at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_71] 
 at lambdainternal.EventHandlerLoader$PojoMethodRequestHandler.handleRequest(EventHandlerLoader.java:439) [lambda-sandbox.jar:na] 
 at lambdainternal.EventHandlerLoader$PojoHandlerAsStreamHandler.handleRequest(EventHandlerLoader.java:370) [lambda-sandbox.jar:na] 
 at lambdainternal.EventHandlerLoader$2.call(EventHandlerLoader.java:972) [lambda-sandbox.jar:na] 
 at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:231) [lambda-sandbox.jar:na] 
 at lambdainternal.AWSLambda.<clinit>(AWSLambda.java:59) [lambda-sandbox.jar:na] 
 at java.lang.Class.forName0(Native Method) [na:1.8.0_71] 
 at java.lang.Class.forName(Class.java:348) [na:1.8.0_71] 
 at lambdainternal.LambdaRTEntry.main(LambdaRTEntry.java:93) [runtime/:na] 
Caused by: java.net.UnknownHostException: ip-10-0-77-249: unknown error 
 at java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method) ~[na:1.8.0_71] 
 at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928) ~[na:1.8.0_71] 
 at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323) ~[na:1.8.0_71] 
 at java.net.InetAddress.getLocalHost(InetAddress.java:1500) ~[na:1.8.0_71]

我从 java.net.UnknownHostException 了解到该函数无法找到 localhost 的主机名并退回到本地环回。

Answer 1

jar 被加载到 S3 容器并连接到 VPC 以访问 RDS 和互联网。

当您启用 VPC 访问时，您实际上禁用了对 VPC 外部任何内容的访问。您没有通过启用 VPC 为 Lambda 函数提供 Internet 访问权限，您实际上删除了 Internet 访问权限。此外，该函数不再有权访问 AWS API 服务器，这就是您在尝试访问 S3 时收到该错误的原因。您应该阅读this blog post announcing VPC support for Lambda 末尾的“须知”部分。

如果您希望 Lambda 函数能够访问互联网和 AWS API 以及您的 VPC 之外的所有其他内容，那么您需要将 NAT Gateway 添加到您的 VPC。

如果您只想将 S3 访问权限添加到您的 Lambda 函数，还有一个额外的选项是使用 S3 VPC Endpoint。

Answer 2

似乎错误出在 AWS 方面。在昨天 AWS 对 Lambda 函数的停机之后，错误消失了。虽然我很好奇是什么原因。