如何用卡西巴插入演员的MongoDB？

Question

假设：

• MongoDB正在本地主机上运行:27017
• 该项目以https://github.com/sap1ens/akka-microservice为模型。如果下面没有足够的信息来帮助，请参考它。如果太混乱，我可以在必要时从其他文件中添加代码。

基于的RegistrationsService.scala问题

• 为什么它试图连接到MongoDB并在启动时插入文档，然后才将任何PostRegistrationMessage发送给RegistrationsService参与者？
• 为什么失败了？
• 如何将registrationJsValue转换为MongoDBObject并将其插入到集合中？

相关信息在build.sbt中

scalaVersion := "2.10.4"

val akkaVersion = "2.3.8"

val sprayVersion = "1.3.1"

// Main dependencies
libraryDependencies ++= Seq(
    "com.typesafe.akka" %% "akka-actor" % akkaVersion,
    "com.typesafe.akka" %% "akka-slf4j" % akkaVersion,
    "io.spray" % "spray-can" % sprayVersion,
    "io.spray" % "spray-routing" % sprayVersion,
    "io.spray" % "spray-client" % sprayVersion,
    "io.spray" %% "spray-json" % sprayVersion,
    "com.typesafe" % "config" % "1.2.1",
    "ch.qos.logback" % "logback-classic" % "1.1.2",
    "org.mongodb" %% "casbah" % "2.7.4"
)

RegistrationService.scala (类似于git中的ExampleService.scala )

package service

import akka.actor.{Props, ActorLogging, Actor}
import spray.json._
import com.mongodb.util.JSON
import com.mongodb.casbah.Imports._
import model.Registration
import model.RegistrationProtocol._

object RegistrationsService {
  case class PostRegistrationMessage(registration: Registration)

  def props(property: String) = Props(classOf[RegistrationsService], property)
}

class RegistrationsService(property: String) extends Actor with ActorLogging {
  import RegistrationsService._

  def receive = {
    case PostRegistrationMessage(registration) => {

      val registrationJsValue = registration.toJson
      val dbObject = JSON.parse(registrationJsValue.toString()).asInstanceOf[DBObject]

      val mongoClientURI = MongoClientURI("mongodb://localhost:27017/")
      val mongoClient = MongoClient(mongoClientURI)
      val someDB = mongoClient("somedb")
      val registrationsColl = someDB("registratoins")
      log.info(s"Got access to registratoins collection")

      registrationsColl.insert(MongoDBObject("hello" -> "world"))
      log.info(s"Inserted a doc to registratoins collection")

      mongoClient.close()
      log.info(s"Closed client connection to mongo")

      sender() ! registrationJsValue
    }
  }
}

sbt运行

14:01:10.655 [microservice-system-akka.actor.default-dispatcher-3] INFO  c.e.a.s.RegistrationsService - Got access to registratoins collection
14:01:11.383 [microservice-system-akka.actor.default-dispatcher-3] DEBUG spray.can.server.HttpListener - Binding to localhost/127.0.0.1:8878
14:01:11.475 [microservice-system-akka.actor.default-dispatcher-3] DEBUG akka.io.TcpListener - Successfully bound to /127.0.0.1:8878
14:01:11.480 [microservice-system-akka.actor.default-dispatcher-6] INFO  spray.can.server.HttpListener - Bound to localhost/127.0.0.1:8878
14:01:20.704 [microservice-system-akka.actor.default-dispatcher-5] ERROR akka.actor.OneForOneStrategy - Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=localhost:27017, type=Unknown, state=Connecting, exception={java.lang.NullPointerException}}]
com.mongodb.MongoTimeoutException: Timed out after 10000 ms while waiting for a server that matches AnyServerSelector{}. Client view of cluster state is {type=Unknown, servers=[{address=localhost:27017, type=Unknown, state=Connecting, exception={java.lang.NullPointerException}}]
    at com.mongodb.BaseCluster.getServer(BaseCluster.java:82) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBTCPConnector.getServer(DBTCPConnector.java:654) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBTCPConnector.access$300(DBTCPConnector.java:39) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBTCPConnector$MyPort.getConnection(DBTCPConnector.java:503) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBTCPConnector$MyPort.get(DBTCPConnector.java:451) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBTCPConnector.getPrimaryPort(DBTCPConnector.java:409) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBCollectionImpl.insert(DBCollectionImpl.java:182) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBCollectionImpl.insert(DBCollectionImpl.java:165) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.DBCollection.insert(DBCollection.java:93) ~[mongo-java-driver-2.12.4.jar:na]
    at com.mongodb.casbah.MongoCollectionBase$class.insert(MongoCollection.scala:621) ~[casbah-core_2.10-2.7.4.jar:2.7.4]
    at com.mongodb.casbah.MongoCollection.insert(MongoCollection.scala:1109) ~[casbah-core_2.10-2.7.4.jar:2.7.4]
    at service.RegistrationsService$$anonfun$receive$1.applyOrElse(RegistrationsService.scala:47) ~[classes/:na]
    at akka.actor.Actor$class.aroundReceive(Actor.scala:465) ~[akka-actor_2.10-2.3.8.jar:na]
    at service.RegistrationsService.aroundReceive(RegistrationsService.scala:20) ~[classes/:na]
    at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516) [akka-actor_2.10-2.3.8.jar:na]
    at akka.actor.ActorCell.invoke(ActorCell.scala:487) [akka-actor_2.10-2.3.8.jar:na]
    at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:254) [akka-actor_2.10-2.3.8.jar:na]
    at akka.dispatch.Mailbox.run(Mailbox.scala:221) [akka-actor_2.10-2.3.8.jar:na]
    at akka.dispatch.Mailbox.exec(Mailbox.scala:231) [akka-actor_2.10-2.3.8.jar:na]
    at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) [scala-library.jar:na]
    at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) [scala-library.jar:na]
    at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [scala-library.jar:na]
    at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [scala-library.jar:na]
^C14:01:42.231 [microservice-system-akka.actor.default-dispatcher-11] INFO  akka.actor.LocalActorRef - Message [akka.actor.Terminated] from Actor[akka://microservice-system/user/$a#1754981697] to Actor[akka://microservice-system/user/IO-HTTP/listener-0#-602059531] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
14:01:42.236 [microservice-system-akka.actor.default-dispatcher-11] DEBUG akka.event.EventStream - shutting down: StandardOutLogger started

Answer 1

不知道你说的是什么意思。

为什么它试图连接到MongoDB并在启动时插入文档，然后才将任何PostRegistrationMessage发送给RegistrationsService参与者？

在示例代码(对于RegistrationsService)中，您已经显示了所建立的唯一连接是在Actor的接收方法中。除非您(或其他代码正在发送此消息)，否则参与者将不会尝试连接到Mongo。

另外，您要在Actor的receive方法中创建一个Mongo连接吗？您应该避免在receive方法中进行任何繁重的操作。您可以在Actor之外创建一个Mongo连接，然后将它注入Actor的构造函数中，以便在接收方法中使用。

您是否编写了一个独立的程序/测试，使用casbah驱动程序连接到您的MongoDB？它应该独立于您的参与者代码，并将帮助您隔离驱动程序和连接代码中的任何问题(如果存在)。

这可能不是你的问题的答案，但我不想写在评论部分，因为篇幅和格式的限制。