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Version: 2.x

Java Platform/System Logger

Java Platform/System Logger is logging API which was introduced in Java 9.

In order to use this logging backend, we need to add the following line in our build.sbt file:

libraryDependencies += "dev.zio" %% "zio-logging-jpl" % "2.4.0"

Logger layer:

import zio.logging.backend.JPL

val logger = Runtime.removeDefaultLoggers >>> JPL.jpl

Default JPL logger setup:

  • logger name (by default) is extracted from zio.Trace
    • for example, trace zio.logging.example.JplSimpleApp.run(JplSimpleApp.scala:17) will have zio.logging.example.JplSimpleApp as logger name
    • NOTE: custom logger name may be set by zio.logging.loggerName aspect
  • all annotations (logger name annotation is excluded) are placed at the beginning of log message
  • cause is logged as throwable

See also LogFormat and LogAppender

Custom logger name set by aspect:

ZIO.logInfo("Starting user operation") @@ zio.logging.loggerName("zio.logging.example.UserOperation")

Examples​

You can find the source code here

Java Platform/System logger name and annotations​

package zio.logging.example

import zio.logging.LogAnnotation
import zio.logging.backend.JPL
import zio.{ ExitCode, Runtime, Scope, ZIO, ZIOAppDefault, _ }

import java.util.UUID

object JplSimpleApp extends ZIOAppDefault {

  override val bootstrap: ZLayer[ZIOAppArgs, Any, Any] = Runtime.removeDefaultLoggers >>> JPL.jpl

  private val users = List.fill(2)(UUID.randomUUID())

  override def run: ZIO[Scope, Any, ExitCode] =
    for {
      _       <- ZIO.logInfo("Start")
      traceId <- ZIO.succeed(UUID.randomUUID())
      _       <- ZIO.foreachPar(users) { uId =>
        {
          ZIO.logInfo("Starting user operation") *>
            ZIO.sleep(500.millis) *>
            ZIO.logInfo("Stopping user operation")
        } @@ ZIOAspect.annotated("user", uId.toString)
      } @@ LogAnnotation.TraceId(traceId) @@ zio.logging.loggerName("zio.logging.example.UserOperation")
      _       <- ZIO.logInfo("Done")
    } yield ExitCode.success

}

Expected Console Output:

Oct 28, 2022 1:47:01 PM zio.logging.backend.JPL$$anon$1 $anonfun$closeLogEntry$1
INFO: Start
Oct 28, 2022 1:47:01 PM zio.logging.backend.JPL$$anon$1 $anonfun$closeLogEntry$1
INFO: user=59c114fd-676d-4df9-a5a0-b8e132468fbf trace_id=7d3e3b84-dd3b-44ff-915a-04fb2d135e28 Starting user operation
Oct 28, 2022 1:47:01 PM zio.logging.backend.JPL$$anon$1 $anonfun$closeLogEntry$1
INFO: user=e1ebf0cc-2f61-484f-afcd-de7e20ec7829 trace_id=7d3e3b84-dd3b-44ff-915a-04fb2d135e28 Starting user operation
Oct 28, 2022 1:47:02 PM zio.logging.backend.JPL$$anon$1 $anonfun$closeLogEntry$1
INFO: user=e1ebf0cc-2f61-484f-afcd-de7e20ec7829 trace_id=7d3e3b84-dd3b-44ff-915a-04fb2d135e28 Stopping user operation
Oct 28, 2022 1:47:02 PM zio.logging.backend.JPL$$anon$1 $anonfun$closeLogEntry$1
INFO: user=59c114fd-676d-4df9-a5a0-b8e132468fbf trace_id=7d3e3b84-dd3b-44ff-915a-04fb2d135e28 Stopping user operation
Oct 28, 2022 1:47:02 PM zio.logging.backend.JPL$$anon$1 $anonfun$closeLogEntry$1
INFO: Done

Feature changes​

Version 2.2.0​

Deprecated log annotation with key jpl_logger_name (JPL.loggerNameAnnotationKey) removed, only common log annotation with key logger_name (zio.logging.loggerNameAnnotationKey) for logger name is supported now.