Hi! I've been trying to (in a very hacky manner) implement a PoC log

+1 This would be helpful for us as well. As a work

I added render on context that returns <code class="n

Support for structured logging about zio-logging HOT 3 CLOSED

zio commented on June 8, 2024 6

Support for structured logging

from zio-logging.

Comments (3)

miguel-vila commented on June 8, 2024 3

This would be helpful for us as well.

As a work around I created a custom slf4j Logging constructor that uses structured logging. It creates a logstash Marker from a zio LogContext. It's far from ideal because annotations need to be known beforehand, as @frekw noted:

object Slf4jWithMarkedAnnotationsLogger {

  private val tracing = Tracing(
    Tracer.globallyCached(new AkkaLineNumbersTracer),
    TracingConfig.enabled
  )

  private def classNameForLambda(lambda: => AnyRef) =
    tracing.tracer.traceLocation(() => lambda) match {
      case SourceLocation(_, clazz, _, _) => Some(clazz)
      case NoLocation(_)                  => None
    }

  private def logger(name: String) =
    ZIO.effectTotal(
      LoggerFactory.getLogger(
        name
      )
    )

  def make(logAnnotations: LogAnnotation[_]*): UIO[Logging] =
    Logging.make { (context, line) =>
      val loggerName = context.get(LogAnnotation.Name) match {
        case Nil   => classNameForLambda(line).getOrElse("ZIO.defaultLogger")
        case names => LogAnnotation.Name.render(names)
      }
      def logContextMarker = logContext2Marker(context, logAnnotations)
      logger(loggerName).map(slf4jLogger =>
        context.get(LogAnnotation.Level).level match {
          case LogLevel.Off.level => ()
          case LogLevel.Debug.level =>
            slf4jLogger.debug(logContextMarker, line)
          case LogLevel.Trace.level =>
            slf4jLogger.trace(logContextMarker, line)
          case LogLevel.Info.level =>
            slf4jLogger.info(logContextMarker, line)
          case LogLevel.Warn.level =>
            slf4jLogger.warn(logContextMarker, line)
          case LogLevel.Error.level =>
            slf4jLogger.error(logContextMarker, line)
          case LogLevel.Fatal.level =>
            slf4jLogger.error(logContextMarker, line)
      })
    }

  private def logContext2Marker(
      logContext: LogContext,
      logAnnotations: Seq[LogAnnotation[_]]): Marker = {
    import net.logstash.logback.marker.Markers._
    import scala.collection.JavaConverters._

    def fromLogAnnotation[A](logAnnotation: LogAnnotation[A]): Marker =
      append(
        logAnnotation.name,
        logAnnotation.render(logContext.get(logAnnotation))
      )

    aggregate(logAnnotations.map(l => fromLogAnnotation(l)).asJava)
  }

}