使用 SLF4J MDC 进行 Scala Akka 日志记录 [英] Scala Akka Logging with SLF4J MDC

问题描述

我正在配置我的 Akka 应用程序以使用此处指定的 SLF4J 记录器:

I'm configuring my Akka application to use the SLF4J logger as specified here:

http://doc.akka.io/docs/akka/2.3.4/scala/logging.html

在幕后，我依靠 Logback 进行日志记录.我正在开发一个用于日志记录的通用模块，用户可以在他们的演员系统中使用它.主要是，我正在创建一个他们可以混合的特征.

Underneath the hood, I'm depending on Logback to do the logging. I'm developing a common module for logging purposes that users can use in their actor systems. Mainly, I'm creating a trait they can mixin.

我有一个特点:

我有这样的东西:

trait ActorLogger {

    val log: DiagnosticLoggingAdapter = Logging(this);

}

我有一些额外的逻辑可以将 MDC 值添加到 DiagnosticLoggingAdapter 的 MDC.现在的问题是:如果用户想要混合到他们的非演员类中，我会完全公开一个不同的记录器.所以我可能有这样的事情:

I have some extra logic which will add MDC values to the DiagnosticLoggingAdapter's MDC. The problem is now this: I expose a different logger entirely if users want to mixin to their non-actor classes. So I might have something like this:

trait ClassLogger {

    val log = LoggerFactory getLogger getClass.getName
}

我希望将 MDC 值转移到这个记录器.例如，如果我将 MDC 值放入我的 DiagnosticAdapterLogger，我应该能够从 org.slf4j.MDC 获取这些值

I want the MDC values to carry over to this logger. So for example, if I put MDC values into my DiagnosticAdapterLogger, I should expect to be able to get those values from org.slf4j.MDC

如何以干净的方式实现这一目标?

How can this be achieved in a clean way?

谢谢！

推荐答案

如果你在 actor 系统之外的所有代码都是单线程的(即你没有产生任何额外的期货或线程)，那么有一个比那个更简单的解决方案@jasop 引用.

If all your code outside the actor system is single-threaded (i.e. you don't spawn any additional futures or threads), there's a simpler solution than the one @jasop references.

我有这个 mixin 负责填充 MDC 的内部和外部 actor:

I have this mixin that takes care of populating the MDC both inside and outside actors:

import akka.actor.DiagnosticActorLogging
import akka.contrib.pattern.ReceivePipeline
import org.slf4j.MDC
import scala.collection.JavaConverters.mapAsJavaMapConverter

trait MdcActorLogging extends DiagnosticActorLogging {
  this: ReceivePipeline =>

  /**
    * This is for logging in Akka actors.
    */
  override def mdc(message: Any): akka.event.Logging.MDC = {
    message match {
      case MyMessage(requestId) => Map("requestId" -> requestId)
      case _ => Map()
    }
  }

  /**
    * This makes the MDC accessible for logging outside of Akka actors by wrapping the actor's
    * `receive` method.
    * Implements the [[http://doc.akka.io/docs/akka/2.4/contrib/receive-pipeline.html ReceivePipeline]]
    * pattern.
    */
  pipelineOuter {
    case e @ MyMessage(requestId) =>
      val origContext = MDC.getCopyOfContextMap
      val mdcWithPath = Map("requestId" -> requestId,
        // inside actors this is already provided, but outside we have to add this manually
        "akkaSource" -> self.path.toString)
      MDC.setContextMap(mdcWithPath.asJava)
      ReceivePipeline.Inner(evt) // invoke actual actor logic
        .andAfter {
          if (origContext != null)
            MDC.setContextMap(origContext)
          else
            MDC.clear()
        }
    case e => ReceivePipeline.Inner(e) // pass through
  }
}

非演员代码可以使用任何记录器，例如混入 com.typesafe.scalalogging.LazyLogging 特性.

The non-actor code can use any logger, e.g. mix in the com.typesafe.scalalogging.LazyLogging trait.

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