在Akka-http中处理SIGTERM

Question

当前（10.1.3）Akka HTTP文档：

https://doc.akka.io/docs/akka-http/current/server-side/graceful-termination.html

使用以下代码示例讨论正常终止：

import akka.actor.ActorSystem
import akka.http.scaladsl.server.Directives._
import akka.http.scaladsl.server.Route
import akka.stream.ActorMaterializer
import scala.concurrent.duration._

implicit val system = ActorSystem()
implicit val dispatcher = system.dispatcher
implicit val materializer = ActorMaterializer()

val routes = get {
  complete("Hello world!")
}

val binding: Future[Http.ServerBinding] =
    Http().bindAndHandle(routes, "127.0.0.1", 8080)

// ...
// once ready to terminate the server, invoke terminate:
val onceAllConnectionsTerminated: Future[Http.HttpTerminated] =
Await.result(binding, 10.seconds)
  .terminate(hardDeadline = 3.seconds)

// once all connections are terminated,
// - you can invoke coordinated shutdown to tear down the rest of the system:
onceAllConnectionsTerminated.flatMap { _ ⇒
  system.terminate()
}

我想知道在什么时候被调用，评论指出：

// once ready to terminate the server

这到底是什么意思，即谁/什么决定服务器已准备好终止？

我是否必须将关闭代码放在某个挂钩函数中的某个位置，以便在接收到SIGTERM的Akka HTTP上调用它？

我尝试将其放入关闭挂钩：

CoordinatedShutdown(system).addCancellableJvmShutdownHook{
  // once ready to terminate the server, invoke terminate:
  val onceAllConnectionsTerminated: Future[Http.HttpTerminated] =
  Await.result(binding, 10.seconds)
    .terminate(hardDeadline = 3.seconds)

  // once all connections are terminated,
  // - you can invoke coordinated shutdown to tear down the rest of the system:
  onceAllConnectionsTerminated.flatMap { _ ⇒
    system.terminate()
  }
}

但是，进行中的请求会在发送SIGTERM（kill）后立即终止，而不是完成。

我还发现从https://github.com/akka/akka-http/issues/1210#issuecomment-338825745关闭的方式略有不同：

CoordinatedShutdown(system).addTask(
    CoordinatedShutdown.PhaseServiceUnbind, "http_shutdown") { () =>

    bind.flatMap(_.unbind).flatMap { _ =>
      Http().shutdownAllConnectionPools
    }.map { _ =>
      Done
    }
  }

也许我应该使用它来处理SIGTERM？ 我不确定..

谢谢！

Answer 1

从这里的答案中得到的解决方案：

https://discuss.lightbend.com/t/graceful-termination-on-sigterm-using-akka-http/1619

CoordinatedShutdown(system).addTask(
    CoordinatedShutdown.PhaseServiceUnbind, "http_shutdown") { () =>

    bind.flatMap(_.terminate(hardDeadline = 1.minute)).map { _ =>
      Done
    }
  }

对我而言，主要部分是增加akka.coordinated-shutdown.default-phase-timeout，因为完成请求的处理要比5秒的默认时间更长。 您也可以增加该阶段的超时。 我的日志中有以下消息：

Coordinated shutdown phase [service-unbind] timed out after 5000 milliseconds